0.18.0

	CanCreate(user, newMeta *meta.Meta) bool

	// User is allowed to read zettel
	CanRead(user, m *meta.Meta) bool

	// User is allowed to write zettel.
	CanWrite(user, oldMeta, newMeta *meta.Meta) bool

	// User is allowed to rename zettel
	CanRename(user, m *meta.Meta) bool

	// User is allowed to delete zettel.
	CanDelete(user, m *meta.Meta) bool

	// User is allowed to refresh box data.
	CanRefresh(user *meta.Meta) bool
}

func (ap *anonPolicy) CanRead(user, m *meta.Meta) bool {
	return ap.pre.CanRead(user, m) && ap.checkVisibility(m)
}

func (ap *anonPolicy) CanWrite(user, oldMeta, newMeta *meta.Meta) bool {
	return ap.pre.CanWrite(user, oldMeta, newMeta) && ap.checkVisibility(oldMeta)
}

func (ap *anonPolicy) CanRename(user, m *meta.Meta) bool {
	return ap.pre.CanRename(user, m) && ap.checkVisibility(m)
}

func (ap *anonPolicy) CanDelete(user, m *meta.Meta) bool {
	return ap.pre.CanDelete(user, m) && ap.checkVisibility(m)
}

func (ap *anonPolicy) CanRefresh(user *meta.Meta) bool {
	if ap.authConfig.GetExpertMode() || ap.authConfig.GetSimpleMode() {

		return err
	}
	if pp.policy.CanWrite(user, oldZettel.Meta, zettel.Meta) {
		return pp.box.UpdateZettel(ctx, zettel)
	}
	return box.NewErrNotAllowed("Write", user, zid)
}

func (pp *polBox) AllowRenameZettel(ctx context.Context, zid id.Zid) bool {
	return pp.box.AllowRenameZettel(ctx, zid)
}

func (pp *polBox) RenameZettel(ctx context.Context, curZid, newZid id.Zid) error {
	z, err := pp.box.GetZettel(ctx, curZid)
	if err != nil {
		return err
	}
	user := server.GetUser(ctx)
	if pp.policy.CanRename(user, z.Meta) {
		return pp.box.RenameZettel(ctx, curZid, newZid)
	}
	return box.NewErrNotAllowed("Rename", user, curZid)
}

func (pp *polBox) CanDeleteZettel(ctx context.Context, zid id.Zid) bool {
	return pp.box.CanDeleteZettel(ctx, zid)
}

func (pp *polBox) DeleteZettel(ctx context.Context, zid id.Zid) error {
	z, err := pp.box.GetZettel(ctx, zid)

}

func (*defaultPolicy) CanCreate(_, _ *meta.Meta) bool { return true }
func (*defaultPolicy) CanRead(_, _ *meta.Meta) bool   { return true }
func (d *defaultPolicy) CanWrite(user, oldMeta, _ *meta.Meta) bool {
	return d.canChange(user, oldMeta)
}
func (d *defaultPolicy) CanRename(user, m *meta.Meta) bool { return d.canChange(user, m) }
func (d *defaultPolicy) CanDelete(user, m *meta.Meta) bool { return d.canChange(user, m) }

func (*defaultPolicy) CanRefresh(user *meta.Meta) bool { return user != nil }

func (d *defaultPolicy) canChange(user, m *meta.Meta) bool {
	metaRo, ok := m.Get(api.KeyReadOnly)
	if !ok {

	}
	switch userRole := o.manager.GetUserRole(user); userRole {
	case meta.UserRoleReader, meta.UserRoleCreator:
		return false
	}
	return o.userCanCreate(user, newMeta)
}

func (o *ownerPolicy) CanRename(user, m *meta.Meta) bool {
	if user == nil || !o.pre.CanRename(user, m) {
		return false
	}
	if res, ok := o.checkVisibility(user, o.authConfig.GetVisibility(m)); ok {
		return res
	}
	return o.userIsOwner(user)
}

func (o *ownerPolicy) CanDelete(user, m *meta.Meta) bool {
	if user == nil || !o.pre.CanDelete(user, m) {
		return false
	}
	if res, ok := o.checkVisibility(user, o.authConfig.GetVisibility(m)); ok {
		return res

	return m != nil && p.post.CanRead(user, m)
}

func (p *prePolicy) CanWrite(user, oldMeta, newMeta *meta.Meta) bool {
	return oldMeta != nil && newMeta != nil && oldMeta.Zid == newMeta.Zid &&
		p.post.CanWrite(user, oldMeta, newMeta)
}

func (p *prePolicy) CanRename(user, m *meta.Meta) bool {
	return m != nil && p.post.CanRename(user, m)
}

func (p *prePolicy) CanDelete(user, m *meta.Meta) bool {
	return m != nil && p.post.CanDelete(user, m)
}

func (p *prePolicy) CanRefresh(user *meta.Meta) bool {
	return p.post.CanRefresh(user)

		)
		name := fmt.Sprintf("readonly=%v/withauth=%v/expert=%v/simple=%v",
			ts.readonly, ts.withAuth, ts.expert, ts.simple)
		t.Run(name, func(tt *testing.T) {
			testCreate(tt, pol, ts.withAuth, ts.readonly)
			testRead(tt, pol, ts.withAuth, ts.expert)
			testWrite(tt, pol, ts.withAuth, ts.readonly, ts.expert)
			testRename(tt, pol, ts.withAuth, ts.readonly, ts.expert)
			testDelete(tt, pol, ts.withAuth, ts.readonly, ts.expert)
			testRefresh(tt, pol, ts.withAuth, ts.expert, ts.simple)
		})
	}
}

type testAuthzManager struct {

		{writer, roTrue, roTrue, false},
		{owner, roTrue, roTrue, false},
		{owner2, roTrue, roTrue, false},
	}
	for _, tc := range testCases {
		t.Run("Write", func(tt *testing.T) {
			got := pol.CanWrite(tc.user, tc.old, tc.new)
			if tc.exp != got {
				tt.Errorf("exp=%v, but got=%v", tc.exp, got)
			}
		})
	}
}

func testRename(t *testing.T, pol auth.Policy, withAuth, readonly, expert bool) {
	t.Helper()
	anonUser := newAnon()
	creator := newCreator()
	reader := newReader()
	writer := newWriter()
	owner := newOwner()
	owner2 := newOwner2()
	zettel := newZettel()
	expertZettel := newExpertZettel()
	roFalse := newRoFalseZettel()
	roTrue := newRoTrueZettel()
	roReader := newRoReaderZettel()
	roWriter := newRoWriterZettel()
	roOwner := newRoOwnerZettel()
	notAuthNotReadonly := !withAuth && !readonly
	testCases := []struct {
		user *meta.Meta
		meta *meta.Meta
		exp  bool
	}{
		// No meta
		{anonUser, nil, false},
		{creator, nil, false},
		{reader, nil, false},
		{writer, nil, false},
		{owner, nil, false},
		{owner2, nil, false},
		// Any zettel
		{anonUser, zettel, notAuthNotReadonly},
		{creator, zettel, notAuthNotReadonly},
		{reader, zettel, notAuthNotReadonly},
		{writer, zettel, notAuthNotReadonly},
		{owner, zettel, !readonly},
		{owner2, zettel, !readonly},
		// Expert zettel
		{anonUser, expertZettel, notAuthNotReadonly && expert},
		{creator, expertZettel, notAuthNotReadonly && expert},
		{reader, expertZettel, notAuthNotReadonly && expert},
		{writer, expertZettel, notAuthNotReadonly && expert},
		{owner, expertZettel, !readonly && expert},
		{owner2, expertZettel, !readonly && expert},
		// No r/o zettel
		{anonUser, roFalse, notAuthNotReadonly},
		{creator, roFalse, notAuthNotReadonly},
		{reader, roFalse, notAuthNotReadonly},
		{writer, roFalse, notAuthNotReadonly},
		{owner, roFalse, !readonly},
		{owner2, roFalse, !readonly},
		// Reader r/o zettel
		{anonUser, roReader, false},
		{creator, roReader, false},
		{reader, roReader, false},
		{writer, roReader, notAuthNotReadonly},
		{owner, roReader, !readonly},
		{owner2, roReader, !readonly},
		// Writer r/o zettel
		{anonUser, roWriter, false},
		{creator, roWriter, false},
		{reader, roWriter, false},
		{writer, roWriter, false},
		{owner, roWriter, !readonly},
		{owner2, roWriter, !readonly},
		// Owner r/o zettel
		{anonUser, roOwner, false},
		{creator, roOwner, false},
		{reader, roOwner, false},
		{writer, roOwner, false},
		{owner, roOwner, false},
		{owner2, roOwner, false},
		// r/o = true zettel
		{anonUser, roTrue, false},
		{creator, roTrue, false},
		{reader, roTrue, false},
		{writer, roTrue, false},
		{owner, roTrue, false},
		{owner2, roTrue, false},
	}
	for _, tc := range testCases {
		t.Run("Rename", func(tt *testing.T) {
			got := pol.CanRename(tc.user, tc.meta)
			if tc.exp != got {
				tt.Errorf("exp=%v, but got=%v", tc.exp, got)
			}
		})
	}
}

import "zettelstore.de/z/zettel/meta"

type roPolicy struct{}

func (*roPolicy) CanCreate(_, _ *meta.Meta) bool   { return false }
func (*roPolicy) CanRead(_, _ *meta.Meta) bool     { return true }
func (*roPolicy) CanWrite(_, _, _ *meta.Meta) bool { return false }
func (*roPolicy) CanRename(_, _ *meta.Meta) bool   { return false }
func (*roPolicy) CanDelete(_, _ *meta.Meta) bool   { return false }
func (*roPolicy) CanRefresh(user *meta.Meta) bool  { return user != nil }

type BaseBox interface {
	// Location returns some information where the box is located.
	// Format is dependent of the box.
	Location() string

	// GetZettel retrieves a specific zettel.
	GetZettel(ctx context.Context, zid id.Zid) (zettel.Zettel, error)

	// AllowRenameZettel returns true, if box will not disallow renaming the zettel.
	AllowRenameZettel(ctx context.Context, zid id.Zid) bool

	// RenameZettel changes the current Zid to a new Zid.
	RenameZettel(ctx context.Context, curZid, newZid id.Zid) error

	// CanDeleteZettel returns true, if box could possibly delete the given zettel.
	CanDeleteZettel(ctx context.Context, zid id.Zid) bool

	// DeleteZettel removes the zettel from the box.
	DeleteZettel(ctx context.Context, zid id.Zid) error
}

type UpdateReason uint8

// Values for Reason
const (
	_        UpdateReason = iota
	OnReady               // Box is started and fully operational
	OnReload              // Box was reloaded
	OnZettel              // Something with a zettel happened

)

// UpdateInfo contains all the data about a changed zettel.
type UpdateInfo struct {
	Box    BaseBox
	Reason UpdateReason
	Zid    id.Zid
}

// UpdateFunc is a function to be called when a change is detected.
type UpdateFunc func(UpdateInfo)




// Subject is a box that notifies observers about changes.
type Subject interface {
	// RegisterObserver registers an observer that will be notified
	// if one or all zettel are found to be changed.
	RegisterObserver(UpdateFunc)
}

	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

func init() {
	manager.Register(
		" comp",
		func(u *url.URL, cdata *manager.ConnectData) (box.ManagedBox, error) {
			return getCompBox(cdata.Number, cdata.Enricher, cdata.Mapper), nil
		})
}

type compBox struct {
	log      *logger.Logger
	number   int
	enricher box.Enricher
	mapper   manager.Mapper
}

var myConfig *meta.Meta
var myZettel = map[id.Zid]struct {
	meta    func(id.Zid) *meta.Meta
	content func(context.Context, *compBox) []byte
}{

	// id.MustParse(api.ZidConsole):              {genConsoleM, genConsoleC},
	id.MustParse(api.ZidBoxManager): {genManagerM, genManagerC},
	// id.MustParse(api.ZidIndex):                {genIndexM, genIndexC},
	// id.MustParse(api.ZidQuery):                {genQueryM, genQueryC},
	id.MustParse(api.ZidMetadataKey):          {genKeysM, genKeysC},
	id.MustParse(api.ZidParser):               {genParserM, genParserC},
	id.MustParse(api.ZidStartupConfiguration): {genConfigZettelM, genConfigZettelC},
	id.MustParse(api.ZidWarnings):             {genWarningsM, genWarningsC},
	id.MustParse(api.ZidMapping):              {genMappingM, genMappingC},
}

// Get returns the one program box.
func getCompBox(boxNumber int, mf box.Enricher, mapper manager.Mapper) *compBox {
	return &compBox{
		log: kernel.Main.GetLogger(kernel.BoxService).Clone().
			Str("box", "comp").Int("boxnum", int64(boxNumber)).Child(),
		number:   boxNumber,
		enricher: mf,
		mapper:   mapper,
	}
}

// Setup remembers important values.
func Setup(cfg *meta.Meta) { myConfig = cfg.Clone() }

func (*compBox) Location() string { return "" }

				cb.enricher.Enrich(ctx, m, cb.number)
				handle(m)
			}
		}
	}
	return nil
}

func (*compBox) AllowRenameZettel(_ context.Context, zid id.Zid) bool {
	_, ok := myZettel[zid]
	return !ok
}

func (cb *compBox) RenameZettel(_ context.Context, curZid, _ id.Zid) (err error) {
	if _, ok := myZettel[curZid]; ok {
		err = box.ErrReadOnly
	} else {
		err = box.ErrZettelNotFound{Zid: curZid}
	}
	cb.log.Trace().Err(err).Msg("RenameZettel")
	return err
}

func (*compBox) CanDeleteZettel(context.Context, id.Zid) bool { return false }

func (cb *compBox) DeleteZettel(_ context.Context, zid id.Zid) (err error) {
	if _, ok := myZettel[zid]; ok {
		err = box.ErrReadOnly
	} else {

//-----------------------------------------------------------------------------
// Copyright (c) 2024-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2024-present Detlef Stern
//-----------------------------------------------------------------------------

package compbox

import (
	"bytes"
	"context"

	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

// Zettelstore Identifier Mapping.
//
// In the first stage of migration process, it is a computed zettel showing a
// hypothetical mapping. In later stages, it will be stored as a normal zettel
// that is updated when a new zettel is created or an old zettel is deleted.

func genMappingM(zid id.Zid) *meta.Meta {
	return getTitledMeta(zid, "Zettelstore Identifier Mapping")
}

func genMappingC(ctx context.Context, cb *compBox) []byte {
	var buf bytes.Buffer
	toNew, err := cb.mapper.OldToNewMapping(ctx)
	if err != nil {
		buf.WriteString("**Error while fetching: ")
		buf.WriteString(err.Error())
		buf.WriteString("**\n")
		return buf.Bytes()
	}
	oldZids := id.NewSetCap(len(toNew))
	for zidO := range toNew {
		oldZids.Add(zidO)
	}
	first := true
	oldZids.ForEach(func(zidO id.Zid) {
		if first {
			buf.WriteString("**Note**: this mapping is preliminary.\n")
			buf.WriteString("It only shows you how it could look if the migration is done.\n")
			buf.WriteString("Use this page to update your zettel if something strange is shown.\n")
			buf.WriteString("```\n")
			first = false
		}
		buf.WriteString(zidO.String())
		buf.WriteByte(' ')
		buf.WriteString(toNew[zidO].String())
		buf.WriteByte('\n')
	})
	if !first {
		buf.WriteString("```")
	}
	return buf.Bytes()
}

	var buf bytes.Buffer
	buf.WriteString("|=Name|=Value>\n")
	fmt.Fprintf(&buf, "|Page Size|%d\n", pageSize)
	fmt.Fprintf(&buf, "|Pages|%d\n", m.HeapSys/uint64(pageSize))
	fmt.Fprintf(&buf, "|Heap Objects|%d\n", m.HeapObjects)
	fmt.Fprintf(&buf, "|Heap Sys (KiB)|%d\n", m.HeapSys/1024)
	fmt.Fprintf(&buf, "|Heap Inuse (KiB)|%d\n", m.HeapInuse/1024)


	debug := kernel.Main.GetConfig(kernel.CoreService, kernel.CoreDebug).(bool)
	if debug {
		for i, bysize := range m.BySize {
			fmt.Fprintf(&buf, "|Size %2d: %d|%d - %d → %d\n",
				i, bysize.Size, bysize.Mallocs, bysize.Frees, bysize.Mallocs-bysize.Frees)
		}
	}

//-----------------------------------------------------------------------------
// Copyright (c) 2024-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2024-present Detlef Stern
//-----------------------------------------------------------------------------

package compbox

import (
	"bytes"
	"context"

	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

func genWarningsM(zid id.Zid) *meta.Meta {
	return getTitledMeta(zid, "Zettelstore Warnings")
}

func genWarningsC(ctx context.Context, cb *compBox) []byte {
	var buf bytes.Buffer
	buf.WriteString("* [[Zettel without stored creation date|query:created-missing:true]]\n")
	buf.WriteString("* [[Zettel with strange creation date|query:created<19700101000000]]\n")

	ws, err := cb.mapper.Warnings(ctx)
	if err != nil {
		buf.WriteString("**Error while fetching: ")
		buf.WriteString(err.Error())
		buf.WriteString("**\n")
		return buf.Bytes()
	}
	first := true
	ws.ForEach(func(zid id.Zid) {
		if first {
			first = false
			buf.WriteString("=== Mapper Warnings\n")
		}
		buf.WriteString("* [[")
		buf.WriteString(zid.String())
		buf.WriteString("]]\n")
	})

	return buf.Bytes()
}

 *-----------------------------------------------------------------------------
 */

*,*::before,*::after {
    box-sizing: border-box;
  }
  html {
    font-size: 1rem;
    font-family: serif;
    scroll-behavior: smooth;
    height: 100%;
  }
  body {
    margin: 0;
    min-height: 100vh;

  .zs-dropdown:hover > .zs-dropdown-content { display: block }
  main { padding: 0 1rem }
  article > * + * { margin-top: .5rem }
  article header {
    padding: 0;
    margin: 0;
  }
  h1,h2,h3,h4,h5,h6 { font-family:sans-serif; font-weight:normal }
  h1 { font-size:1.5rem;  margin:.65rem 0 }
  h2 { font-size:1.25rem; margin:.70rem 0 }
  h3 { font-size:1.15rem; margin:.75rem 0 }
  h4 { font-size:1.05rem; margin:.8rem 0; font-weight: bold }
  h5 { font-size:1.05rem; margin:.8rem 0 }
  h6 { font-size:1.05rem; margin:.8rem 0; font-weight: lighter }
  p { margin: .5rem 0 0 0 }
  p.zs-meta-zettel { margin-top: .5rem; margin-left: 0.5rem }
  li,figure,figcaption,dl { margin: 0 }
  dt { margin: .5rem 0 0 0 }
  dt+dd { margin-top: 0 }
  dd { margin: .5rem 0 0 2rem }
  dd > p:first-child { margin: 0 0 0 0 }
  blockquote {
    border-left: 0.5rem solid lightgray;
    padding-left: 1rem;
    margin-left: 1rem;
    margin-right: 2rem;
    font-style: italic;
  }
  blockquote p { margin-bottom: .5rem }
  blockquote cite { font-style: normal }
  table {
    border-collapse: collapse;
    border-spacing: 0;
    max-width: 100%;
  }

  thead>tr>td { border-bottom: 2px solid hsl(0, 0%, 70%); font-weight: bold }
  tfoot>tr>td { border-top: 2px solid hsl(0, 0%, 70%); font-weight: bold }
  td {
    text-align: left;
    padding: .25rem .5rem;
    border-bottom: 1px solid hsl(0, 0%, 85%)
  }
  main form {
    padding: 0 .5em;
    margin: .5em 0 0 0;
  }
  main form:after {
    content: ".";
    display: block;

  input.zs-secondary { float:left }
  input.zs-upload {
    padding-left: 1em;
    padding-right: 1em;
  }
  a:not([class]) { text-decoration-skip-ink: auto }
  a.broken { text-decoration: line-through }
  a.external::after { content: "➚"; display: inline-block }
  img { max-width: 100% }
  img.right { float: right }
  ol.zs-endnotes {
    padding-top: .5rem;
    border-top: 1px solid;
  }
  kbd { font-family:monospace }
  code,pre {
    font-family: monospace;
    font-size: 85%;
  }
  code {
    padding: .1rem .2rem;
    background: #f0f0f0;
    border: 1px solid #ccc;
    border-radius: .25rem;
  }
  pre {
    padding: .5rem .7rem;
    max-width: 100%;
    overflow: auto;
    border: 1px solid #ccc;
    border-radius: .5rem;
    background: #f0f0f0;
  }
  pre code {
    font-size: 95%;
    position: relative;
    padding: 0;
    border: none;
  }
  div.zs-indication {
    padding: .5rem .7rem;
    max-width: 100%;
    border-radius: .5rem;
    border: 1px solid black;
  }
  div.zs-indication p:first-child { margin-top: 0 }
  span.zs-indication {
    border: 1px solid black;
    border-radius: .25rem;
    padding: .1rem .2rem;
    font-size: 95%;
  }
  .zs-info {
    background-color: lightblue;
    padding: .5rem 1rem;
  }
  .zs-warning {
    background-color: lightyellow;
    padding: .5rem 1rem;
  }
  .zs-error {
    background-color: lightpink;
    border-style: none !important;
    font-weight: bold;
  }
  td.left { text-align:left }
  td.center { text-align:center }
  td.right { text-align:right }
  .zs-font-size-0 { font-size:75% }
  .zs-font-size-1 { font-size:83% }
  .zs-font-size-2 { font-size:100% }
  .zs-font-size-3 { font-size:117% }
  .zs-font-size-4 { font-size:150% }
  .zs-font-size-5 { font-size:200% }
  .zs-deprecated { border-style: dashed; padding: .2rem }
  .zs-meta {
    font-size:.75rem;
    color:#444;
    margin-bottom:1rem;
  }
  .zs-meta a { color:#444 }
  h1+.zs-meta { margin-top:-1rem }
  nav > details { margin-top:1rem }
  details > summary {
    width: 100%;
    background-color: #eee;
    font-family:sans-serif;
  }
  details > ul {
    margin-top:0;
    padding-left:2rem;
    background-color: #eee;
  }
  footer { padding: 0 1rem }
  @media (prefers-reduced-motion: reduce) {
    * {
      animation-duration: 0.01ms !important;
      animation-iteration-count: 1 !important;
      transition-duration: 0.01ms !important;
      scroll-behavior: auto !important;
    }
  }

	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

func init() {
	manager.Register(
		" const",
		func(u *url.URL, cdata *manager.ConnectData) (box.ManagedBox, error) {
			return &constBox{
				log: kernel.Main.GetLogger(kernel.BoxService).Clone().
					Str("box", "const").Int("boxnum", int64(cdata.Number)).Child(),
				number:   cdata.Number,
				zettel:   constZettelMap,
				enricher: cdata.Enricher,
			}, nil

			m := meta.NewWithData(zid, zettel.header)
			cb.enricher.Enrich(ctx, m, cb.number)
			handle(m)
		}
	}
	return nil
}

func (cb *constBox) AllowRenameZettel(_ context.Context, zid id.Zid) bool {
	_, ok := cb.zettel[zid]
	return !ok
}

func (cb *constBox) RenameZettel(_ context.Context, curZid, _ id.Zid) (err error) {
	if _, ok := cb.zettel[curZid]; ok {
		err = box.ErrReadOnly
	} else {
		err = box.ErrZettelNotFound{Zid: curZid}
	}
	cb.log.Trace().Err(err).Msg("RenameZettel")
	return err
}

func (*constBox) CanDeleteZettel(context.Context, id.Zid) bool { return false }

func (cb *constBox) DeleteZettel(_ context.Context, zid id.Zid) (err error) {
	if _, ok := cb.zettel[zid]; ok {
		err = box.ErrReadOnly
	} else {

		zettel.NewContent(contentLoginSxn)},
	id.ZettelTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Zettel HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20230510155300",
			api.KeyModified:   "20240219145100",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentZettelSxn)},
	id.InfoTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Info HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20200804111624",
			api.KeyModified:   "20240618170000",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentInfoSxn)},
	id.FormTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Form HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20200804111624",
			api.KeyModified:   "20240219145200",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentFormSxn)},
	id.RenameTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Rename Form HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20200804111624",
			api.KeyModified:   "20240219145200",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentRenameSxn)},
	id.DeleteTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Delete HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20200804111624",
			api.KeyModified:   "20240219145200",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentDeleteSxn)},
	id.ListTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore List Zettel HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,

		zettel.NewContent(contentStartCodeSxn)},
	id.BaseSxnZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Sxn Base Code",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20230619132800",
			api.KeyModified:   "20240618170100",
			api.KeyReadOnly:   api.ValueTrue,
			api.KeyVisibility: api.ValueVisibilityExpert,
			api.KeyPrecursor:  string(api.ZidSxnPrelude),
		},
		zettel.NewContent(contentBaseCodeSxn)},
	id.PreludeSxnZid: {
		constHeader{

		zettel.NewContent(contentPreludeSxn)},
	id.MustParse(api.ZidBaseCSS): {
		constHeader{
			api.KeyTitle:      "Zettelstore Base CSS",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxCSS,
			api.KeyCreated:    "20200804111624",
			api.KeyModified:   "20231129112800",
			api.KeyVisibility: api.ValueVisibilityPublic,
		},
		zettel.NewContent(contentBaseCSS)},
	id.MustParse(api.ZidUserCSS): {
		constHeader{
			api.KeyTitle:      "Zettelstore User CSS",
			api.KeyRole:       api.ValueRoleConfiguration,

			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxGif,
			api.KeyReadOnly:   api.ValueTrue,
			api.KeyCreated:    "20210504175807",
			api.KeyVisibility: api.ValueVisibilityPublic,
		},
		zettel.NewContent(contentEmoji)},










	id.TOCNewTemplateZid: {
		constHeader{
			api.KeyTitle:      "New Menu",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxZmk,
			api.KeyLang:       api.ValueLangEN,
			api.KeyCreated:    "20210217161829",
			api.KeyModified:   "20231129111800",
			api.KeyVisibility: api.ValueVisibilityCreator,
		},
		zettel.NewContent(contentNewTOCZettel)},
	id.MustParse(api.ZidTemplateNewZettel): {
		constHeader{
			api.KeyTitle:                 "New Zettel",
			api.KeyRole:                  api.ValueRoleConfiguration,
			api.KeySyntax:                meta.SyntaxZmk,
			api.KeyCreated:               "20201028185209",
			api.KeyModified:              "20230929132900",

		},
		zettel.NewContent(contentRoleZettel)},
	id.MustParse(api.ZidRoleConfigurationZettel): {
		constHeader{
			api.KeyTitle:      api.ValueRoleConfiguration,
			api.KeyRole:       api.ValueRoleRole,
			api.KeySyntax:     meta.SyntaxZmk,
			api.KeyCreated:    "20231129162800",
			api.KeyLang:       api.ValueLangEN,
			api.KeyVisibility: api.ValueVisibilityLogin,
		},
		zettel.NewContent(contentRoleConfiguration)},
	id.MustParse(api.ZidRoleRoleZettel): {
		constHeader{
			api.KeyTitle:      api.ValueRoleRole,

			api.KeyLang:       api.ValueLangEN,
			api.KeyCreated:    "20240703235900",
			api.KeyVisibility: api.ValueVisibilityLogin,
		},
		zettel.NewContent(nil)},
	id.DefaultHomeZid: {
		constHeader{
			api.KeyTitle:   "Home",
			api.KeyRole:    api.ValueRoleZettel,
			api.KeySyntax:  meta.SyntaxZmk,
			api.KeyLang:    api.ValueLangEN,
			api.KeyCreated: "20210210190757",

		},
		zettel.NewContent(contentHomeZettel)},
}

//go:embed license.txt
var contentLicense []byte

//go:embed info.sxn
var contentInfoSxn []byte

//go:embed form.sxn
var contentFormSxn []byte

//go:embed rename.sxn
var contentRenameSxn []byte

//go:embed delete.sxn
var contentDeleteSxn []byte

//go:embed listzettel.sxn
var contentListZettelSxn []byte

//go:embed error.sxn

//go:embed base.css
var contentBaseCSS []byte

//go:embed emoji_spin.gif
var contentEmoji []byte




//go:embed newtoc.zettel
var contentNewTOCZettel []byte

//go:embed rolezettel.zettel
var contentRoleZettel []byte

//go:embed roleconfiguration.zettel
var contentRoleConfiguration []byte

=== Thank you for using Zettelstore!

You will find the lastest information about Zettelstore at [[https://zettelstore.de]].
Check that website regulary for [[upgrades|https://zettelstore.de/home/doc/trunk/www/download.wiki]] to the latest version.
You should consult the [[change log|https://zettelstore.de/home/doc/trunk/www/changes.wiki]] before upgrading.
Sometimes, you have to edit some of your Zettelstore-related zettel before upgrading.
Since Zettelstore is currently in a development state, every upgrade might fix some of your problems.

If you have problems concerning Zettelstore,
do not hesitate to get in [[contact with the main developer|mailto:ds@zettelstore.de]].

=== Reporting errors
If you have encountered an error, please include the content of the following zettel in your mail (if possible):
* [[Zettelstore Version|00000000000001]]: {{00000000000001}}
* [[Zettelstore Operating System|00000000000003]]
* [[Zettelstore Startup Configuration|00000000000096]]
* [[Zettelstore Runtime Configuration|00000000000100]]

    (p
      (a (@ (href ,web-url)) "Web")
      (@H " · ") (a (@ (href ,context-url)) "Context")
      (@H " / ") (a (@ (href ,context-full-url)) "Full")
      ,@(if (bound? 'edit-url) `((@H " · ") (a (@ (href ,edit-url)) "Edit")))
      ,@(ROLE-DEFAULT-actions (current-binding))
      ,@(if (bound? 'reindex-url) `((@H " · ") (a (@ (href ,reindex-url)) "Reindex")))
      ,@(if (bound? 'rename-url) `((@H " · ") (a (@ (href ,rename-url)) "Rename")))
      ,@(if (bound? 'delete-url) `((@H " · ") (a (@ (href ,delete-url)) "Delete")))
    )
  )
  (h2 "Interpreted Metadata")
  (table ,@(map wui-info-meta-table-row metadata))
  (h2 "References")
  ,@(if local-links `((h3 "Local")    (ul ,@(map wui-local-link local-links)))) 

This zettel lists all zettel that should act as a template for new zettel.
These zettel will be included in the ""New"" menu of the WebUI.
* [[New Zettel|00000000090001]]
* [[New Role|00000000090004]]
* [[New Tag|00000000090003]]
* [[New User|00000000090002]]

;;;----------------------------------------------------------------------------
;;; Copyright (c) 2023-present Detlef Stern
;;;
;;; This file is part of Zettelstore.
;;;
;;; Zettelstore is licensed under the latest version of the EUPL (European
;;; Union Public License). Please see file LICENSE.txt for your rights and
;;; obligations under this license.
;;;
;;; SPDX-License-Identifier: EUPL-1.2
;;; SPDX-FileCopyrightText: 2023-present Detlef Stern
;;;----------------------------------------------------------------------------

`(article
  (header (h1 "Rename Zettel " ,zid))
  (p "Do you really want to rename this zettel?")
  ,@(if incoming
    `((div (@ (class "zs-warning"))
      (h2 "Warning!")
      (p "If you rename this zettel, incoming references from the following zettel will become invalid.")
      (ul ,@(map wui-item-link incoming))
    ))
  )
  ,@(if (and (bound? 'useless) useless)
    `((div (@ (class "zs-warning"))
      (h2 "Warning!")
      (p "Renaming this zettel will also delete the following files, so that they will not be interpreted as content for this zettel.")
      (ul ,@(map wui-item useless))
    ))
  )
  (form (@ (method "POST"))
    (input (@ (type "hidden") (id "curzid") (name "curzid") (value ,zid)))
    (div
      (label (@ (for "newzid")) "New zettel id")
      (input (@ (class "zs-input") (type "text") (inputmode "numeric") (id "newzid") (name "newzid")
                (pattern "\\d{14}")
                (title "New zettel identifier, must be unique")
                (placeholder "ZID..") (value ,zid) (autofocus))))
    (div (input (@ (class "zs-primary") (type "submit") (value "Rename"))))
  )
  ,(wui-meta-desc metapairs)
)

Zettel with role ""configuration"" are used within Zettelstore to manage and to show the current configuration of the software.

Typically, there are some public zettel that show the license of this software, its dependencies, some CSS code to make the default web user interface a litte bit nicer, and the defult image to singal a broken image.



Other zettel are only visible if an user has authenticated itself, or if there is no authentication enabled.
In this case, one additional configuration zettel is the zettel containing the version number of this software.
Other zettel are showing the supported metadata keys and supported syntax values.
Zettel that allow to configure the menu of template to create new zettel are also using the role ""configuration"".

Most important is the zettel that contains the runtime configuration.
You may change its metadata value to change the behaviour of the software.

One configuration is the ""expert mode"".
If enabled, and if you are authorized so see them, you will discover some more zettel.
For example, HTML templates to customize the default web user interface, to show the application log, to see statistics about zettel boxes, to show the host name and it operating system, and many more.

You are allowed to add your own configuration zettel, for example if you want to customize the look and feel of zettel by placing relevant data into your own zettel.

By default, user zettel (for authentification) use also the role ""configuration"".
However, you are allowed to change this.

;; wui-tdata-link taks a pair (text . url) and returns a HTML link inside
;; a table data item.
(defun wui-tdata-link (q) `(td ,(wui-link q)))

;; wui-item-popup-link is like 'wui-item-link, but the HTML link will open
;; a new tab / window.
(defun wui-item-popup-link (e)
    `(li (a (@ (href ,e) (target "_blank") (rel "noopener noreferrer")) ,e)))

;; wui-option-value returns a value for an HTML option element.
(defun wui-option-value (v) `(option (@ (value ,v))))

;; wui-datalist returns a HTML datalist with the given HTML identifier and a
;; list of values.
(defun wui-datalist (id lst)

;; ROLE-DEFAULT-actions returns the default text for actions.
(defun ROLE-DEFAULT-actions (binding)
    `(,@(let ((copy-url (binding-lookup 'copy-url binding)))
             (if (defined? copy-url) `((@H " · ") (a (@ (href ,copy-url)) "Copy"))))
      ,@(let ((version-url (binding-lookup 'version-url binding)))
             (if (defined? version-url) `((@H " · ") (a (@ (href ,version-url)) "Version"))))
      ,@(let ((child-url (binding-lookup 'child-url binding)))
             (if (defined? child-url) `((@H " · ") (a (@ (href ,child-url)) "Child"))))
      ,@(let ((folge-url (binding-lookup 'folge-url binding)))
             (if (defined? folge-url) `((@H " · ") (a (@ (href ,folge-url)) "Folge"))))
    )
)

;; ROLE-tag-actions returns an additional action "Zettel" for zettel with role "tag".
(defun ROLE-tag-actions (binding)

          ,@(if (and (bound? 'folge-role-url) (bound? 'meta-folge-role))
                `((@H " → ") (a (@ (href ,folge-role-url)) ,meta-folge-role)))
      ")"
      ,@(if tag-refs `((@H " · ") ,@tag-refs))
      ,@(ROLE-DEFAULT-actions (current-binding))
      ,@(if predecessor-refs `((br) "Predecessor: " ,predecessor-refs))
      ,@(if precursor-refs `((br) "Precursor: " ,precursor-refs))
      ,@(if superior-refs `((br) "Superior: " ,superior-refs))
      ,@(ROLE-DEFAULT-heading (current-binding))
    )
  )
  ,@content
  ,endnotes
  ,@(if (or folge-links subordinate-links back-links successor-links)
    `((nav
      ,@(if folge-links `((details (@ (,folge-open)) (summary "Folgezettel") (ul ,@(map wui-item-link folge-links)))))
      ,@(if subordinate-links `((details (@ (,subordinate-open)) (summary "Subordinates") (ul ,@(map wui-item-link subordinate-links)))))
      ,@(if back-links `((details (@ (,back-open)) (summary "Incoming") (ul ,@(map wui-item-link back-links)))))
      ,@(if successor-links `((details (@ (,successor-open)) (summary "Successors") (ul ,@(map wui-item-link successor-links)))))
     ))
  )
)

func (dp *dirBox) stopFileServices() {
	for _, c := range dp.fCmds {
		close(c)
	}
}

func (dp *dirBox) notifyChanged(zid id.Zid) {
	if chci := dp.cdata.Notify; chci != nil {
		dp.log.Trace().Zid(zid).Msg("notifyChanged")
		chci <- box.UpdateInfo{Reason: box.OnZettel, Zid: zid}
	}
}

func (dp *dirBox) getFileChan(zid id.Zid) chan fileCmd {
	// Based on https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
	sum := 2166136261 ^ uint32(zid)
	sum *= 16777619

	entry := notify.DirEntry{Zid: newZid}
	dp.updateEntryFromMetaContent(&entry, meta, zettel.Content)

	err = dp.srvSetZettel(ctx, &entry, zettel)
	if err == nil {
		err = dp.dirSrv.UpdateDirEntry(&entry)
	}
	dp.notifyChanged(meta.Zid)
	dp.log.Trace().Err(err).Zid(meta.Zid).Msg("CreateZettel")
	return meta.Zid, err
}

func (dp *dirBox) GetZettel(ctx context.Context, zid id.Zid) (zettel.Zettel, error) {
	entry := dp.dirSrv.GetDirEntry(zid)
	if !entry.IsValid() {

		// Existing zettel, but new in this box.
		entry = &notify.DirEntry{Zid: zid}
	}
	dp.updateEntryFromMetaContent(entry, meta, zettel.Content)
	dp.dirSrv.UpdateDirEntry(entry)
	err := dp.srvSetZettel(ctx, entry, zettel)
	if err == nil {
		dp.notifyChanged(zid)
	}
	dp.log.Trace().Zid(zid).Err(err).Msg("UpdateZettel")
	return err
}

func (dp *dirBox) updateEntryFromMetaContent(entry *notify.DirEntry, m *meta.Meta, content zettel.Content) {
	entry.SetupFromMetaContent(m, content, dp.cdata.Config.GetZettelFileSyntax)
}

func (dp *dirBox) AllowRenameZettel(context.Context, id.Zid) bool {
	return !dp.readonly
}

func (dp *dirBox) RenameZettel(ctx context.Context, curZid, newZid id.Zid) error {
	if curZid == newZid {
		return nil
	}
	curEntry := dp.dirSrv.GetDirEntry(curZid)
	if !curEntry.IsValid() {
		return box.ErrZettelNotFound{Zid: curZid}
	}
	if dp.readonly {
		return box.ErrReadOnly
	}

	// Check whether zettel with new ID already exists in this box.
	if dp.HasZettel(ctx, newZid) {
		return box.ErrInvalidZid{Zid: newZid.String()}
	}

	oldMeta, oldContent, err := dp.srvGetMetaContent(ctx, curEntry, curZid)
	if err != nil {
		return err
	}

	newEntry, err := dp.dirSrv.RenameDirEntry(curEntry, newZid)
	if err != nil {
		return err
	}
	oldMeta.Zid = newZid
	newZettel := zettel.Zettel{Meta: oldMeta, Content: zettel.NewContent(oldContent)}
	if err = dp.srvSetZettel(ctx, &newEntry, newZettel); err != nil {
		// "Rollback" rename. No error checking...
		dp.dirSrv.RenameDirEntry(&newEntry, curZid)
		return err
	}
	err = dp.srvDeleteZettel(ctx, curEntry, curZid)
	if err == nil {
		dp.notifyChanged(curZid)
		dp.notifyChanged(newZid)
	}
	dp.log.Trace().Zid(curZid).Zid(newZid).Err(err).Msg("RenameZettel")
	return err
}

func (dp *dirBox) CanDeleteZettel(_ context.Context, zid id.Zid) bool {
	if dp.readonly {
		return false
	}
	entry := dp.dirSrv.GetDirEntry(zid)
	return entry.IsValid()

	}
	err := dp.dirSrv.DeleteDirEntry(zid)
	if err != nil {
		return nil
	}
	err = dp.srvDeleteZettel(ctx, entry, zid)
	if err == nil {
		dp.notifyChanged(zid)
	}
	dp.log.Trace().Zid(zid).Err(err).Msg("DeleteZettel")
	return err
}

func (dp *dirBox) ReadStats(st *box.ManagedBoxStats) {
	st.ReadOnly = dp.readonly
	st.Zettel = dp.dirSrv.NumDirEntries()
	dp.log.Trace().Int("zettel", int64(st.Zettel)).Msg("ReadStats")
}

)

type zipBox struct {
	log      *logger.Logger
	number   int
	name     string
	enricher box.Enricher
	notify   chan<- box.UpdateInfo
	dirSrv   *notify.DirService
}

func (zb *zipBox) Location() string {
	if strings.HasPrefix(zb.name, "/") {
		return "file://" + zb.name
	}

			continue
		}
		zb.enricher.Enrich(ctx, m, zb.number)
		handle(m)
	}
	return nil
}

func (zb *zipBox) AllowRenameZettel(_ context.Context, zid id.Zid) bool {
	entry := zb.dirSrv.GetDirEntry(zid)
	return !entry.IsValid()
}

func (zb *zipBox) RenameZettel(_ context.Context, curZid, newZid id.Zid) error {
	err := box.ErrReadOnly
	if curZid == newZid {
		err = nil
	}
	curEntry := zb.dirSrv.GetDirEntry(curZid)
	if !curEntry.IsValid() {
		err = box.ErrZettelNotFound{Zid: curZid}
	}
	zb.log.Trace().Err(err).Msg("RenameZettel")
	return err
}

func (*zipBox) CanDeleteZettel(context.Context, id.Zid) bool { return false }

func (zb *zipBox) DeleteZettel(_ context.Context, zid id.Zid) error {
	err := box.ErrReadOnly
	entry := zb.dirSrv.GetDirEntry(zid)
	if !entry.IsValid() {

// GetQueryBool is a helper function to extract bool values from a box URI.
func GetQueryBool(u *url.URL, key string) bool {
	_, ok := u.Query()[key]
	return ok
}

// GetQueryInt is a helper function to extract int values of a specified range from a box URI.
func GetQueryInt(u *url.URL, key string, min, def, max int) int {
	sVal := u.Query().Get(key)
	if sVal == "" {
		return def
	}
	iVal, err := strconv.Atoi(sVal)
	if err != nil {
		return def
	}
	if iVal < min {
		return min
	}
	if iVal > max {
		return max
	}
	return iVal
}

	if box, isWriteBox := mgr.boxes[0].(box.WriteBox); isWriteBox {
		return box.CanCreateZettel(ctx)
	}
	return false
}

// CreateZettel creates a new zettel.
func (mgr *Manager) CreateZettel(ctx context.Context, zettel zettel.Zettel) (id.Zid, error) {
	mgr.mgrLog.Debug().Msg("CreateZettel")
	if err := mgr.checkContinue(ctx); err != nil {
		return id.Invalid, err
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	if box, isWriteBox := mgr.boxes[0].(box.WriteBox); isWriteBox {
		zettel.Meta = mgr.cleanMetaProperties(zettel.Meta)
		zid, err := box.CreateZettel(ctx, zettel)
		if err == nil {
			mgr.idxUpdateZettel(ctx, zettel)
		}
		return zid, err
	}
	return id.Invalid, box.ErrReadOnly
}

// GetZettel retrieves a specific zettel.
func (mgr *Manager) GetZettel(ctx context.Context, zid id.Zid) (zettel.Zettel, error) {
	mgr.mgrLog.Debug().Zid(zid).Msg("GetZettel")
	if err := mgr.checkContinue(ctx); err != nil {
		return zettel.Zettel{}, err
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()



	for i, p := range mgr.boxes {
		var errZNF box.ErrZettelNotFound
		if z, err := p.GetZettel(ctx, zid); !errors.As(err, &errZNF) {
			if err == nil {
				mgr.Enrich(ctx, z.Meta, i+1)
			}
			return z, err

		if err != nil {
			return nil, err
		}
	}
	return result, nil
}

func (mgr *Manager) HasZettel(ctx context.Context, zid id.Zid) bool {
	mgr.mgrLog.Debug().Zid(zid).Msg("HasZettel")
	if err := mgr.checkContinue(ctx); err != nil {
		return false
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	for _, bx := range mgr.boxes {
		if bx.HasZettel(ctx, zid) {
			return true
		}
	}
	return false
}


func (mgr *Manager) GetMeta(ctx context.Context, zid id.Zid) (*meta.Meta, error) {
	mgr.mgrLog.Debug().Zid(zid).Msg("GetMeta")
	if err := mgr.checkContinue(ctx); err != nil {
		return nil, err
	}

	m, err := mgr.idxStore.GetMeta(ctx, zid)
	if err != nil {

		return nil, err
	}
	mgr.Enrich(ctx, m, 0)
	return m, nil
}

// SelectMeta returns all zettel meta data that match the selection

// UpdateZettel updates an existing zettel.
func (mgr *Manager) UpdateZettel(ctx context.Context, zettel zettel.Zettel) error {
	mgr.mgrLog.Debug().Zid(zettel.Meta.Zid).Msg("UpdateZettel")
	if err := mgr.checkContinue(ctx); err != nil {
		return err
	}



	if box, isWriteBox := mgr.boxes[0].(box.WriteBox); isWriteBox {
		zettel.Meta = mgr.cleanMetaProperties(zettel.Meta)
		if err := box.UpdateZettel(ctx, zettel); err != nil {
			return err
		}
		mgr.idxUpdateZettel(ctx, zettel)
		return nil
	}
	return box.ErrReadOnly
}

// AllowRenameZettel returns true, if box will not disallow renaming the zettel.
func (mgr *Manager) AllowRenameZettel(ctx context.Context, zid id.Zid) bool {
	if err := mgr.checkContinue(ctx); err != nil {
		return false
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	for _, p := range mgr.boxes {
		if !p.AllowRenameZettel(ctx, zid) {
			return false
		}
	}
	return true
}

// RenameZettel changes the current zid to a new zid.
func (mgr *Manager) RenameZettel(ctx context.Context, curZid, newZid id.Zid) error {
	mgr.mgrLog.Debug().Zid(curZid).Zid(newZid).Msg("RenameZettel")
	if err := mgr.checkContinue(ctx); err != nil {
		return err
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	for i, p := range mgr.boxes {
		err := p.RenameZettel(ctx, curZid, newZid)
		var errZNF box.ErrZettelNotFound
		if err != nil && !errors.As(err, &errZNF) {
			for j := range i {
				mgr.boxes[j].RenameZettel(ctx, newZid, curZid)
			}
			return err
		}
	}
	mgr.idxRenameZettel(ctx, curZid, newZid)
	return nil
}

// CanDeleteZettel returns true, if box could possibly delete the given zettel.
func (mgr *Manager) CanDeleteZettel(ctx context.Context, zid id.Zid) bool {
	if err := mgr.checkContinue(ctx); err != nil {
		return false
	}
	mgr.mgrMx.RLock()

	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	for _, p := range mgr.boxes {
		err := p.DeleteZettel(ctx, zid)
		if err == nil {
			mgr.idxDeleteZettel(ctx, zid)
			return nil
		}
		var errZNF box.ErrZettelNotFound
		if !errors.As(err, &errZNF) && !errors.Is(err, box.ErrReadOnly) {
			return err
		}
	}
	return box.ErrZettelNotFound{Zid: zid}

	"zettelstore.de/z/box"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

// Enrich computes additional properties and updates the given metadata.
func (mgr *Manager) Enrich(ctx context.Context, m *meta.Meta, boxNumber int) {

	// Calculate computed, but stored values.
	_, hasCreated := m.Get(api.KeyCreated)
	if !hasCreated {
		m.Set(api.KeyCreated, computeCreated(m.Zid))
	}

	if box.DoEnrich(ctx) {

	}
	return true
}

func (mgr *Manager) idxUpdateZettel(ctx context.Context, zettel zettel.Zettel) {
	var cData collectData
	cData.initialize()

	collectZettelIndexData(parser.ParseZettel(ctx, zettel, "", mgr.rtConfig), &cData)


	m := zettel.Meta
	zi := store.NewZettelIndex(m)
	mgr.idxCollectFromMeta(ctx, m, zi, &cData)
	mgr.idxProcessData(ctx, zi, &cData)
	toCheck := mgr.idxStore.UpdateReferences(ctx, zi)
	mgr.idxCheckZettel(toCheck)
}





func (mgr *Manager) idxCollectFromMeta(ctx context.Context, m *meta.Meta, zi *store.ZettelIndex, cData *collectData) {
	for _, pair := range m.ComputedPairs() {
		descr := meta.GetDescription(pair.Key)
		if descr.IsProperty() {
			continue
		}
		switch descr.Type {

	} else {
		stWords.Add(value)
	}
}

func (mgr *Manager) idxProcessData(ctx context.Context, zi *store.ZettelIndex, cData *collectData) {
	cData.refs.ForEach(func(ref id.Zid) {
		if mgr.HasZettel(ctx, ref) {
			zi.AddBackRef(ref)
		} else {
			zi.AddDeadRef(ref)
		}
	})
	zi.SetWords(cData.words)
	zi.SetUrls(cData.urls)
}

func (mgr *Manager) idxUpdateValue(ctx context.Context, inverseKey, value string, zi *store.ZettelIndex) {
	zid, err := id.Parse(value)
	if err != nil {
		return
	}
	if !mgr.HasZettel(ctx, zid) {
		zi.AddDeadRef(zid)
		return
	}
	if inverseKey == "" {
		zi.AddBackRef(zid)
		return
	}
	zi.AddInverseRef(inverseKey, zid)
}

func (mgr *Manager) idxRenameZettel(ctx context.Context, curZid, newZid id.Zid) {
	toCheck := mgr.idxStore.RenameZettel(ctx, curZid, newZid)
	mgr.idxCheckZettel(toCheck)
}

func (mgr *Manager) idxDeleteZettel(ctx context.Context, zid id.Zid) {
	toCheck := mgr.idxStore.DeleteZettel(ctx, zid)
	mgr.idxCheckZettel(toCheck)
}

func (mgr *Manager) idxCheckZettel(s *id.Set) {
	s.ForEach(func(zid id.Zid) {
		mgr.idxAr.EnqueueZettel(zid)
	})
}

)

// ConnectData contains all administration related values.
type ConnectData struct {
	Number   int // number of the box, starting with 1.
	Config   config.Config
	Enricher box.Enricher
	Notify   chan<- box.UpdateInfo
	Mapper   Mapper
}

// Mapper allows to inspect the mapping between old-style and new-style zettel identifier.
type Mapper interface {
	Warnings(context.Context) (*id.Set, error) // Fetch problematic zettel identifier

	OldToNewMapping(ctx context.Context) (map[id.Zid]id.ZidN, error)
}

// Connect returns a handle to the specified box.
func Connect(u *url.URL, authManager auth.BaseManager, cdata *ConnectData) (box.ManagedBox, error) {
	if authManager.IsReadonly() {
		rawURL := u.String()
		// TODO: the following is wrong under some circumstances:

	rtConfig     config.Config
	boxes        []box.ManagedBox
	observers    []box.UpdateFunc
	mxObserver   sync.RWMutex
	done         chan struct{}
	infos        chan box.UpdateInfo
	propertyKeys strfun.Set // Set of property key names
	zidMapper    *zidMapper

	// Indexer data
	idxLog   *logger.Logger
	idxStore store.Store
	idxAr    *anteroomQueue
	idxReady chan struct{} // Signal a non-empty anteroom to background task

	// Indexer stats data
	idxMx          sync.RWMutex
	idxLastReload  time.Time
	idxDurReload   time.Duration
	idxSinceReload uint64
}

func (mgr *Manager) setState(newState box.StartState) {
	mgr.stateMx.Lock()
	mgr.state = newState
	mgr.stateMx.Unlock()
}


func (mgr *Manager) State() box.StartState {
	mgr.stateMx.RLock()
	state := mgr.state
	mgr.stateMx.RUnlock()
	return state
}

		propertyKeys: propertyKeys,

		idxLog:   boxLog.Clone().Str("box", "index").Child(),
		idxStore: createIdxStore(rtConfig),
		idxAr:    newAnteroomQueue(1000),
		idxReady: make(chan struct{}, 1),
	}
	mgr.zidMapper = NewZidMapper(mgr)

	cdata := ConnectData{Number: 1, Config: rtConfig, Enricher: mgr, Notify: mgr.infos, Mapper: mgr.zidMapper}
	boxes := make([]box.ManagedBox, 0, len(boxURIs)+2)
	for _, uri := range boxURIs {
		p, err := Connect(uri, authManager, &cdata)
		if err != nil {
			return nil, err
		}
		if p != nil {

				reason, zid := ci.Reason, ci.Zid
				mgr.mgrLog.Debug().Uint("reason", uint64(reason)).Zid(zid).Msg("notifier")
				if ignoreUpdate(cache, now, reason, zid) {
					mgr.mgrLog.Trace().Uint("reason", uint64(reason)).Zid(zid).Msg("notifier ignored")
					continue
				}


				mgr.idxEnqueue(reason, zid)
				if ci.Box == nil {
					ci.Box = mgr
				}
				if mgr.State() == box.StartStateStarted {
					mgr.notifyObserver(&ci)
				}
			}
		case <-mgr.done:
			return
		}
	}

func (mgr *Manager) idxEnqueue(reason box.UpdateReason, zid id.Zid) {
	switch reason {
	case box.OnReady:
		return
	case box.OnReload:
		mgr.idxAr.Reset()
	case box.OnZettel:


		mgr.idxAr.EnqueueZettel(zid)
	default:
		mgr.mgrLog.Error().Uint("reason", uint64(reason)).Zid(zid).Msg("Unknown notification reason")
		return
	}
	select {
	case mgr.idxReady <- struct{}{}:

	}
	mgr.idxAr.Reset() // Ensure an initial index run
	mgr.done = make(chan struct{})
	go mgr.notifier()

	mgr.waitBoxesAreStarted()
	mgr.setState(box.StartStateStarted)

	mgr.notifyObserver(&box.UpdateInfo{Box: mgr, Reason: box.OnReady})

	go mgr.idxIndexer()
	return nil
}

func (mgr *Manager) waitBoxesAreStarted() {

// ReIndex data of the given zettel.
func (mgr *Manager) ReIndex(ctx context.Context, zid id.Zid) error {
	mgr.mgrLog.Debug().Msg("ReIndex")
	if err := mgr.checkContinue(ctx); err != nil {
		return err
	}
	mgr.infos <- box.UpdateInfo{Reason: box.OnZettel, Zid: zid}
	return nil
}

// ReadStats populates st with box statistics.
func (mgr *Manager) ReadStats(st *box.Stats) {
	mgr.mgrLog.Debug().Msg("ReadStats")
	mgr.mgrMx.RLock()

func (mgr *Manager) checkContinue(ctx context.Context) error {
	if mgr.State() != box.StartStateStarted {
		return box.ErrStopped
	}
	return ctx.Err()
}

	if zi, ok := ms.idx[zid]; ok {
		return zi
	}
	zi := &zettelData{}
	ms.idx[zid] = zi
	return zi
}

func (ms *mapStore) RenameZettel(_ context.Context, curZid, newZid id.Zid) *id.Set {
	ms.mx.Lock()
	defer ms.mx.Unlock()

	curZi, curFound := ms.idx[curZid]
	_, newFound := ms.idx[newZid]
	if !curFound || newFound {
		return nil
	}
	newZi := &zettelData{
		meta:      copyMeta(curZi.meta, newZid),
		dead:      ms.copyDeadReferences(curZi.dead),
		forward:   ms.copyForward(curZi.forward, newZid),
		backward:  nil, // will be done through tocheck
		otherRefs: nil, // TODO: check if this will be done through toCheck
		words:     copyStrings(ms.words, curZi.words, newZid),
		urls:      copyStrings(ms.urls, curZi.urls, newZid),
	}

	ms.idx[newZid] = newZi
	toCheck := ms.doDeleteZettel(curZid)
	toCheck = toCheck.IUnion(ms.dead[newZid])
	delete(ms.dead, newZid)
	toCheck = toCheck.Add(newZid) // should update otherRefs
	return toCheck
}
func copyMeta(m *meta.Meta, newZid id.Zid) *meta.Meta {
	result := m.Clone()
	result.Zid = newZid
	return result
}

func (ms *mapStore) copyDeadReferences(curDead *id.Set) *id.Set {
	// Must only be called if ms.mx is write-locked!
	curDead.ForEach(func(ref id.Zid) {
		ms.dead[ref] = ms.dead[ref].Add(ref)
	})
	return curDead.Clone()
}
func (ms *mapStore) copyForward(curForward *id.Set, newZid id.Zid) *id.Set {
	// Must only be called if ms.mx is write-locked!
	curForward.ForEach(func(ref id.Zid) {
		if fzi, found := ms.idx[ref]; found {
			fzi.backward = fzi.backward.Add(newZid)
		}

	})
	return curForward.Clone()
}
func copyStrings(msStringMap stringRefs, curStrings []string, newZid id.Zid) []string {
	// Must only be called if ms.mx is write-locked!
	if l := len(curStrings); l > 0 {
		result := make([]string, l)
		for i, s := range curStrings {
			result[i] = s
			msStringMap[s] = msStringMap[s].Add(newZid)
		}
		return result
	}
	return nil
}

func (ms *mapStore) DeleteZettel(_ context.Context, zid id.Zid) *id.Set {
	ms.mx.Lock()
	defer ms.mx.Unlock()
	return ms.doDeleteZettel(zid)
}

	// Entrich metadata with data from store.
	Enrich(ctx context.Context, m *meta.Meta)

	// UpdateReferences for a specific zettel.
	// Returns set of zettel identifier that must also be checked for changes.
	UpdateReferences(context.Context, *ZettelIndex) *id.Set

	// RenameZettel changes all references of current zettel identifier to new
	// zettel identifier.
	RenameZettel(_ context.Context, curZid, newZid id.Zid) *id.Set

	// DeleteZettel removes index data for given zettel.
	// Returns set of zettel identifier that must also be checked for changes.
	DeleteZettel(context.Context, id.Zid) *id.Set

	// Optimize removes unneeded space.
	Optimize()

//-----------------------------------------------------------------------------
// Copyright (c) 2021-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2021-present Detlef Stern
//-----------------------------------------------------------------------------

package manager

import (
	"context"
	"maps"
	"sync"
	"time"

	"zettelstore.de/z/zettel/id"
)

// zidMapper transforms old-style zettel identifier (14 digits) into new one (4 alphanums).
//
// Since there are no new-style identifier defined, there is only support for old-style
// identifier by checking, whether they are suported as new-style or not.
//
// This will change in later versions.
type zidMapper struct {
	fetcher   zidfetcher
	defined   map[id.Zid]id.ZidN // predefined mapping, constant after creation
	mx        sync.RWMutex       // protect toNew ... nextZidN
	toNew     map[id.Zid]id.ZidN // working mapping old->new
	toOld     map[id.ZidN]id.Zid // working mapping new->old
	nextZidM  id.ZidN            // next zid for manual
	hadManual bool
	nextZidN  id.ZidN // next zid for normal zettel
}

type zidfetcher interface {
	fetchZids(context.Context) (*id.Set, error)
}

// NewZidMapper creates a new ZipMapper.
func NewZidMapper(fetcher zidfetcher) *zidMapper {
	defined := map[id.Zid]id.ZidN{
		id.Invalid: id.InvalidN,
		1:          id.MustParseN("0001"), // ZidVersion
		2:          id.MustParseN("0002"), // ZidHost
		3:          id.MustParseN("0003"), // ZidOperatingSystem
		4:          id.MustParseN("0004"), // ZidLicense
		5:          id.MustParseN("0005"), // ZidAuthors
		6:          id.MustParseN("0006"), // ZidDependencies
		7:          id.MustParseN("0007"), // ZidLog
		8:          id.MustParseN("0008"), // ZidMemory
		9:          id.MustParseN("0009"), // ZidSx
		10:         id.MustParseN("000a"), // ZidHTTP
		11:         id.MustParseN("000b"), // ZidAPI
		12:         id.MustParseN("000c"), // ZidWebUI
		13:         id.MustParseN("000d"), // ZidConsole
		20:         id.MustParseN("000e"), // ZidBoxManager
		21:         id.MustParseN("000f"), // ZidZettel
		22:         id.MustParseN("000g"), // ZidIndex
		23:         id.MustParseN("000h"), // ZidQuery
		90:         id.MustParseN("000i"), // ZidMetadataKey
		92:         id.MustParseN("000j"), // ZidParser
		96:         id.MustParseN("000k"), // ZidStartupConfiguration
		100:        id.MustParseN("000l"), // ZidRuntimeConfiguration
		101:        id.MustParseN("000m"), // ZidDirectory
		102:        id.MustParseN("000n"), // ZidWarnings
		10100:      id.MustParseN("000s"), // Base HTML Template
		10200:      id.MustParseN("000t"), // Login Form Template
		10300:      id.MustParseN("000u"), // List Zettel Template
		10401:      id.MustParseN("000v"), // Detail Template
		10402:      id.MustParseN("000w"), // Info Template
		10403:      id.MustParseN("000x"), // Form Template
		10404:      id.MustParseN("001z"), // Rename Form Template (will be removed in the future)
		10405:      id.MustParseN("000y"), // Delete Template
		10700:      id.MustParseN("000z"), // Error Template
		19000:      id.MustParseN("000q"), // Sxn Start Code
		19990:      id.MustParseN("000r"), // Sxn Base Code
		20001:      id.MustParseN("0010"), // Base CSS
		25001:      id.MustParseN("0011"), // User CSS
		40001:      id.MustParseN("000o"), // Generic Emoji
		59900:      id.MustParseN("000p"), // Sxn Prelude
		60010:      id.MustParseN("0012"), // zettel
		60020:      id.MustParseN("0013"), // confguration
		60030:      id.MustParseN("0014"), // role
		60040:      id.MustParseN("0015"), // tag
		90000:      id.MustParseN("0016"), // New Menu
		90001:      id.MustParseN("0017"), // New Zettel
		90002:      id.MustParseN("0018"), // New User
		90003:      id.MustParseN("0019"), // New Tag
		90004:      id.MustParseN("001a"), // New Role
		// 100000000,   // Manual               -> 0020-00yz
		9999999997:  id.MustParseN("00zx"), // ZidSession
		9999999998:  id.MustParseN("00zy"), // ZidAppDirectory
		9999999999:  id.MustParseN("00zz"), // ZidMapping
		10000000000: id.MustParseN("0100"), // ZidDefaultHome
	}
	toNew := maps.Clone(defined)
	toOld := make(map[id.ZidN]id.Zid, len(toNew))
	for o, n := range toNew {
		if _, found := toOld[n]; found {
			panic("duplicate predefined zid")
		}
		toOld[n] = o
	}

	return &zidMapper{
		fetcher:   fetcher,
		defined:   defined,
		toNew:     toNew,
		toOld:     toOld,
		nextZidM:  id.MustParseN("0020"),
		hadManual: false,
		nextZidN:  id.MustParseN("0101"),
	}
}

// isWellDefined returns true, if the given zettel identifier is predefined
// (as stated in the manual), or is part of the manual itself, or is greater than
// 19699999999999.
func (zm *zidMapper) isWellDefined(zid id.Zid) bool {
	if _, found := zm.defined[zid]; found || (1000000000 <= zid && zid <= 1099999999) {
		return true
	}
	if _, err := time.Parse("20060102150405", zid.String()); err != nil {
		return false
	}
	return 19700000000000 <= zid
}

// Warnings returns all zettel identifier with warnings.
func (zm *zidMapper) Warnings(ctx context.Context) (*id.Set, error) {
	allZids, err := zm.fetcher.fetchZids(ctx)
	if err != nil {
		return nil, err
	}
	warnings := id.NewSet()
	allZids.ForEach(func(zid id.Zid) {
		if !zm.isWellDefined(zid) {
			warnings = warnings.Add(zid)
		}
	})
	return warnings, nil
}

func (zm *zidMapper) GetZidN(zidO id.Zid) id.ZidN {
	zm.mx.RLock()
	if zidN, found := zm.toNew[zidO]; found {
		zm.mx.RUnlock()
		return zidN
	}
	zm.mx.RUnlock()

	zm.mx.Lock()
	defer zm.mx.Unlock()
	// Double check to avoid races
	if zidN, found := zm.toNew[zidO]; found {
		return zidN
	}

	if 1000000000 <= zidO && zidO <= 1099999999 {
		if zidO == 1000000000 {
			zm.hadManual = true
		}
		if zm.hadManual {
			zidN := zm.nextZidM
			zm.nextZidM++
			zm.toNew[zidO] = zidN
			zm.toOld[zidN] = zidO
			return zidN
		}
	}

	zidN := zm.nextZidN
	zm.nextZidN++
	zm.toNew[zidO] = zidN
	zm.toOld[zidN] = zidO
	return zidN
}

// OldToNewMapping returns the mapping of old format identifier to new format identifier.
func (zm *zidMapper) OldToNewMapping(ctx context.Context) (map[id.Zid]id.ZidN, error) {
	allZids, err := zm.fetcher.fetchZids(ctx)
	if err != nil {
		return nil, err
	}

	result := make(map[id.Zid]id.ZidN, allZids.Length())
	allZids.ForEach(func(zidO id.Zid) {
		zidN := zm.GetZidN(zidO)
		result[zidO] = zidN
	})
	return result, nil
}

	maxZettel int
	maxBytes  int
	mx        sync.RWMutex // Protects the following fields
	zettel    map[id.Zid]zettel.Zettel
	curBytes  int
}

func (mb *memBox) notifyChanged(zid id.Zid) {
	if chci := mb.cdata.Notify; chci != nil {
		chci <- box.UpdateInfo{Box: mb, Reason: box.OnZettel, Zid: zid}
	}
}

func (mb *memBox) Location() string {
	return mb.u.String()
}

	meta := zettel.Meta.Clone()
	meta.Zid = zid
	zettel.Meta = meta
	mb.zettel[zid] = zettel
	mb.curBytes = newBytes
	mb.mx.Unlock()

	mb.notifyChanged(zid)
	mb.log.Trace().Zid(zid).Msg("CreateZettel")
	return zid, nil
}

func (mb *memBox) GetZettel(_ context.Context, zid id.Zid) (zettel.Zettel, error) {
	mb.mx.RLock()
	z, ok := mb.zettel[zid]

		return box.ErrCapacity
	}

	zettel.Meta = m
	mb.zettel[m.Zid] = zettel
	mb.curBytes = newBytes
	mb.mx.Unlock()
	mb.notifyChanged(m.Zid)
	mb.log.Trace().Msg("UpdateZettel")
	return nil
}

func (*memBox) AllowRenameZettel(context.Context, id.Zid) bool { return true }

func (mb *memBox) RenameZettel(_ context.Context, curZid, newZid id.Zid) error {
	mb.mx.Lock()
	zettel, ok := mb.zettel[curZid]
	if !ok {
		mb.mx.Unlock()
		return box.ErrZettelNotFound{Zid: curZid}
	}

	// Check that there is no zettel with newZid
	if _, ok = mb.zettel[newZid]; ok {
		mb.mx.Unlock()
		return box.ErrInvalidZid{Zid: newZid.String()}
	}

	meta := zettel.Meta.Clone()
	meta.Zid = newZid
	zettel.Meta = meta
	mb.zettel[newZid] = zettel
	delete(mb.zettel, curZid)
	mb.mx.Unlock()
	mb.notifyChanged(curZid)
	mb.notifyChanged(newZid)
	mb.log.Trace().Msg("RenameZettel")
	return nil
}

func (mb *memBox) CanDeleteZettel(_ context.Context, zid id.Zid) bool {
	mb.mx.RLock()
	_, ok := mb.zettel[zid]
	mb.mx.RUnlock()
	return ok
}

func (mb *memBox) DeleteZettel(_ context.Context, zid id.Zid) error {
	mb.mx.Lock()
	oldZettel, found := mb.zettel[zid]
	if !found {
		mb.mx.Unlock()
		return box.ErrZettelNotFound{Zid: zid}
	}
	delete(mb.zettel, zid)
	mb.curBytes -= oldZettel.Length()
	mb.mx.Unlock()
	mb.notifyChanged(zid)
	mb.log.Trace().Msg("DeleteZettel")
	return nil
}

func (mb *memBox) ReadStats(st *box.ManagedBoxStats) {
	st.ReadOnly = false
	mb.mx.RLock()
	st.Zettel = len(mb.zettel)
	mb.mx.RUnlock()
	mb.log.Trace().Int("zettel", int64(st.Zettel)).Msg("ReadStats")
}

package notify

import (
	"errors"
	"fmt"
	"path/filepath"
	"regexp"
	"strings"
	"sync"

	"zettelstore.de/z/box"
	"zettelstore.de/z/kernel"
	"zettelstore.de/z/logger"
	"zettelstore.de/z/parser"
	"zettelstore.de/z/query"

// dsCreated --Start--> dsStarting
// dsStarting --last list notification--> dsWorking
// dsWorking --directory missing--> dsMissing
// dsMissing --last list notification--> dsWorking
// --Stop--> dsStopping
type DirServiceState uint8


const (
	DsCreated  DirServiceState = iota
	DsStarting                 // Reading inital scan
	DsWorking                  // Initial scan complete, fully operational
	DsMissing                  // Directory is missing
	DsStopping                 // Service is shut down
)

// DirService specifies a directory service for file based zettel.
type DirService struct {
	box      box.ManagedBox
	log      *logger.Logger
	dirPath  string
	notifier Notifier
	infos    chan<- box.UpdateInfo
	mx       sync.RWMutex // protects status, entries
	state    DirServiceState
	entries  entrySet
}

// ErrNoDirectory signals missing directory data.
var ErrNoDirectory = errors.New("unable to retrieve zettel directory information")

// NewDirService creates a new directory service.
func NewDirService(box box.ManagedBox, log *logger.Logger, notifier Notifier, chci chan<- box.UpdateInfo) *DirService {
	return &DirService{
		box:      box,
		log:      log,
		notifier: notifier,
		infos:    chci,
		state:    DsCreated,
	}
}

// State the current service state.
func (ds *DirService) State() DirServiceState {
	ds.mx.RLock()

	defer ds.mx.Unlock()
	if ds.entries == nil {
		return ds.logMissingEntry("update")
	}
	ds.entries[entry.Zid] = &entry
	return nil
}

// RenameDirEntry replaces an existing directory entry with a new one.
func (ds *DirService) RenameDirEntry(oldEntry *DirEntry, newZid id.Zid) (DirEntry, error) {
	ds.mx.Lock()
	defer ds.mx.Unlock()
	if ds.entries == nil {
		return DirEntry{}, ds.logMissingEntry("rename")
	}
	if _, found := ds.entries[newZid]; found {
		return DirEntry{}, box.ErrInvalidZid{Zid: newZid.String()}
	}
	oldZid := oldEntry.Zid
	newEntry := DirEntry{
		Zid:         newZid,
		MetaName:    renameFilename(oldEntry.MetaName, oldZid, newZid),
		ContentName: renameFilename(oldEntry.ContentName, oldZid, newZid),
		ContentExt:  oldEntry.ContentExt,
		// Duplicates must not be set, because duplicates will be deleted
	}
	delete(ds.entries, oldZid)
	ds.entries[newZid] = &newEntry
	return newEntry, nil
}

func renameFilename(name string, curID, newID id.Zid) string {
	if cur := curID.String(); strings.HasPrefix(name, cur) {
		name = newID.String() + name[len(cur):]
	}
	return name
}

// DeleteDirEntry removes a entry from the directory.
func (ds *DirService) DeleteDirEntry(zid id.Zid) error {
	ds.mx.Lock()
	defer ds.mx.Unlock()
	if ds.entries == nil {
		return ds.logMissingEntry("delete")

		ds.log.Error().Str("path", ds.dirPath).Msg("Zettel directory missing")
		return nil, true
	case Update:
		ds.mx.Lock()
		zid := ds.onUpdateFileEvent(ds.entries, ev.Name)
		ds.mx.Unlock()
		if zid != id.Invalid {
			ds.notifyChange(zid)
		}
	case Delete:
		ds.mx.Lock()
		zid := ds.onDeleteFileEvent(ds.entries, ev.Name)
		ds.mx.Unlock()
		if zid != id.Invalid {
			ds.notifyChange(zid)
		}
	default:
		ds.log.Error().Str("event", fmt.Sprintf("%v", ev)).Msg("Unknown zettel notification event")
	}
	return newEntries, true
}

func getNewZids(entries entrySet) id.Slice {
	zids := make(id.Slice, 0, len(entries))
	for zid := range entries {
		zids = append(zids, zid)
	}
	return zids
}

func (ds *DirService) onCreateDirectory(zids id.Slice, prevEntries entrySet) {
	for _, zid := range zids {
		ds.notifyChange(zid)
		delete(prevEntries, zid)
	}

	// These were previously stored, by are not found now.
	// Notify system that these were deleted, e.g. for updating the index.
	for zid := range prevEntries {
		ds.notifyChange(zid)
	}
}

func (ds *DirService) onDestroyDirectory() {
	ds.mx.Lock()
	entries := ds.entries
	ds.entries = nil
	ds.state = DsMissing
	ds.mx.Unlock()
	for zid := range entries {
		ds.notifyChange(zid)
	}
}

var validFileName = regexp.MustCompile(`^(\d{14})`)

func matchValidFileName(name string) []string {
	return validFileName.FindStringSubmatch(name)

	newLen := len(newExt)
	if oldLen != newLen {
		return newLen < oldLen
	}
	return newExt < oldExt
}

func (ds *DirService) notifyChange(zid id.Zid) {
	if chci := ds.infos; chci != nil {
		ds.log.Trace().Zid(zid).Msg("notifyChange")
		chci <- box.UpdateInfo{Box: ds.box, Reason: box.OnZettel, Zid: zid}
	}
}

	ucQuery.SetEvaluate(&ucEvaluate)
	ucTagZettel := usecase.NewTagZettel(protectedBoxManager, &ucQuery)
	ucRoleZettel := usecase.NewRoleZettel(protectedBoxManager, &ucQuery)
	ucListSyntax := usecase.NewListSyntax(protectedBoxManager)
	ucListRoles := usecase.NewListRoles(protectedBoxManager)
	ucDelete := usecase.NewDeleteZettel(logUc, protectedBoxManager)
	ucUpdate := usecase.NewUpdateZettel(logUc, protectedBoxManager)
	ucRename := usecase.NewRenameZettel(logUc, protectedBoxManager)
	ucRefresh := usecase.NewRefresh(logUc, protectedBoxManager)
	ucReIndex := usecase.NewReIndex(logUc, protectedBoxManager)
	ucVersion := usecase.NewVersion(kernel.Main.GetConfig(kernel.CoreService, kernel.CoreVersion).(string))

	a := api.New(
		webLog.Clone().Str("adapter", "api").Child(),
		webSrv, authManager, authManager, rtConfig, authPolicy)
	wui := webui.New(
		webLog.Clone().Str("adapter", "wui").Child(),
		webSrv, authManager, rtConfig, authManager, boxManager, authPolicy, &ucEvaluate)

	webSrv.Handle("/", wui.MakeGetRootHandler(protectedBoxManager))
	if assetDir := kern.GetConfig(kernel.WebService, kernel.WebAssetDir).(string); assetDir != "" {
		const assetPrefix = "/assets/"
		webSrv.Handle(assetPrefix, http.StripPrefix(assetPrefix, http.FileServer(http.Dir(assetDir))))
		webSrv.Handle("/favicon.ico", wui.MakeFaviconHandler(assetDir))
	}

	// Web user interface
	if !authManager.IsReadonly() {
		webSrv.AddZettelRoute('b', server.MethodGet, wui.MakeGetRenameZettelHandler(ucGetZettel))
		webSrv.AddZettelRoute('b', server.MethodPost, wui.MakePostRenameZettelHandler(&ucRename))
		webSrv.AddListRoute('c', server.MethodGet, wui.MakeGetZettelFromListHandler(&ucQuery, &ucEvaluate, ucListRoles, ucListSyntax))
		webSrv.AddListRoute('c', server.MethodPost, wui.MakePostCreateZettelHandler(&ucCreateZettel))
		webSrv.AddZettelRoute('c', server.MethodGet, wui.MakeGetCreateZettelHandler(
			ucGetZettel, &ucCreateZettel, ucListRoles, ucListSyntax))
		webSrv.AddZettelRoute('c', server.MethodPost, wui.MakePostCreateZettelHandler(&ucCreateZettel))
		webSrv.AddZettelRoute('d', server.MethodGet, wui.MakeGetDeleteZettelHandler(ucGetZettel, ucGetAllZettel))
		webSrv.AddZettelRoute('d', server.MethodPost, wui.MakePostDeleteZettelHandler(&ucDelete))

	webSrv.AddListRoute('x', server.MethodPost, a.MakePostCommandHandler(&ucIsAuth, &ucRefresh))
	webSrv.AddListRoute('z', server.MethodGet, a.MakeQueryHandler(&ucQuery, &ucTagZettel, &ucRoleZettel, &ucReIndex))
	webSrv.AddZettelRoute('z', server.MethodGet, a.MakeGetZettelHandler(ucGetZettel, ucParseZettel, ucEvaluate))
	if !authManager.IsReadonly() {
		webSrv.AddListRoute('z', server.MethodPost, a.MakePostCreateZettelHandler(&ucCreateZettel))
		webSrv.AddZettelRoute('z', server.MethodPut, a.MakeUpdateZettelHandler(&ucUpdate))
		webSrv.AddZettelRoute('z', server.MethodDelete, a.MakeDeleteZettelHandler(&ucDelete))
		webSrv.AddZettelRoute('z', server.MethodMove, a.MakeRenameZettelHandler(&ucRename))
	}

	if authManager.WithAuth() {
		webSrv.SetUserRetriever(usecase.NewGetUserByZid(boxManager))
	}
}

type getUserImpl struct{}

func (*getUserImpl) GetUser(ctx context.Context) *meta.Meta { return server.GetUser(ctx) }

	}
}

const (
	keyAdminPort         = "admin-port"
	keyAssetDir          = "asset-dir"
	keyBaseURL           = "base-url"

	keyDebug             = "debug-mode"
	keyDefaultDirBoxType = "default-dir-box-type"
	keyInsecureCookie    = "insecure-cookie"
	keyInsecureHTML      = "insecure-html"
	keyListenAddr        = "listen-addr"
	keyLogLevel          = "log-level"
	keyMaxRequestSize    = "max-request-size"
	keyOwner             = "owner"
	keyPersistentCookie  = "persistent-cookie"
	keyBoxOneURI         = kernel.BoxURIs + "1"
	keyReadOnly          = "read-only-mode"

	keyTokenLifetimeHTML = "token-lifetime-html"
	keyTokenLifetimeAPI  = "token-lifetime-api"
	keyURLPrefix         = "url-prefix"
	keyVerbose           = "verbose-mode"
)

func setServiceConfig(cfg *meta.Meta) bool {

		val, found := cfg.Get(key)
		if !found {
			break
		}
		err = setConfigValue(err, kernel.BoxService, key, val)
	}


	err = setConfigValue(err, kernel.ConfigService, kernel.ConfigInsecureHTML, cfg.GetDefault(keyInsecureHTML, kernel.ConfigSecureHTML))


	err = setConfigValue(err, kernel.WebService, kernel.WebListenAddress, cfg.GetDefault(keyListenAddr, "127.0.0.1:23123"))
	if val, found := cfg.Get(keyBaseURL); found {
		err = setConfigValue(err, kernel.WebService, kernel.WebBaseURL, val)
	}
	if val, found := cfg.Get(keyURLPrefix); found {
		err = setConfigValue(err, kernel.WebService, kernel.WebURLPrefix, val)
	}
	err = setConfigValue(err, kernel.WebService, kernel.WebSecureCookie, !cfg.GetBool(keyInsecureCookie))
	err = setConfigValue(err, kernel.WebService, kernel.WebPersistentCookie, cfg.GetBool(keyPersistentCookie))
	if val, found := cfg.Get(keyMaxRequestSize); found {
		err = setConfigValue(err, kernel.WebService, kernel.WebMaxRequestSize, val)
	}
	err = setConfigValue(
		err, kernel.WebService, kernel.WebTokenLifetimeAPI, cfg.GetDefault(keyTokenLifetimeAPI, ""))
	err = setConfigValue(
		err, kernel.WebService, kernel.WebTokenLifetimeHTML, cfg.GetDefault(keyTokenLifetimeHTML, ""))

	if val, found := cfg.Get(keyAssetDir); found {
		err = setConfigValue(err, kernel.WebService, kernel.WebAssetDir, val)
	}
	return err == nil
}

func setConfigValue(err error, subsys kernel.Service, key string, val any) error {

import (
	"os"

	"zettelstore.de/z/cmd"
)

// Version variable. Will be filled by build process.
var version string = ""

func main() {
	exitCode := cmd.Main("Zettelstore", version)
	os.Exit(exitCode)
}

//-----------------------------------------------------------------------------

// Package collect provides functions to collect items from a syntax tree.
package collect

import "zettelstore.de/z/ast"

// Order of internal reference within the given zettel.
func Order(zn *ast.ZettelNode) (result []*ast.Reference) {
	for _, bn := range zn.Ast {
		ln, ok := bn.(*ast.NestedListNode)
		if !ok {
			continue
		}
		switch ln.Kind {
		case ast.NestedListOrdered, ast.NestedListUnordered:
			for _, is := range ln.Items {
				if ref := firstItemZettelReference(is); ref != nil {
					result = append(result, ref)
				}
			}
		}
	}
	return result
}

func firstItemZettelReference(is ast.ItemSlice) *ast.Reference {
	for _, in := range is {
		if pn, ok := in.(*ast.ParaNode); ok {
			if ref := firstInlineZettelReference(pn.Inlines); ref != nil {
				return ref
			}
		}
	}
	return nil
}

func firstInlineZettelReference(is ast.InlineSlice) (result *ast.Reference) {
	for _, inl := range is {
		switch in := inl.(type) {
		case *ast.LinkNode:
			if ref := in.Ref; ref.IsZettel() {
				return ref
			}
			result = firstInlineZettelReference(in.Inlines)
		case *ast.EmbedRefNode:
			result = firstInlineZettelReference(in.Inlines)
		case *ast.EmbedBLOBNode:
			result = firstInlineZettelReference(in.Inlines)
		case *ast.CiteNode:
			result = firstInlineZettelReference(in.Inlines)
		case *ast.FootnoteNode:
			// Ignore references in footnotes
			continue
		case *ast.FormatNode:
			result = firstInlineZettelReference(in.Inlines)
		default:
			continue
		}
		if result != nil {
			return result
		}
	}

	"context"

	"zettelstore.de/z/zettel/meta"
)

// Key values that are supported by Config.Get
const (
	KeyFooterZettel         = "footer-zettel"
	KeyHomeZettel           = "home-zettel"
	KeyShowBackLinks        = "show-back-links"
	KeyShowFolgeLinks       = "show-folge-links"
	KeyShowSubordinateLinks = "show-subordinate-links"
	KeyShowSuccessorLinks   = "show-successor-links"
	// api.KeyLang
)

// Config allows to retrieve all defined configuration values that can be changed during runtime.
type Config interface {
	AuthConfig

id: 20210916193200
title: Required Software
role: zettel
syntax: zmk
created: 20210916193200
modified: 20231213194509

The following software must be installed:

* A current, supported [[release of Go|https://go.dev/doc/devel/release]],
* [[Fossil|https://fossil-scm.org/]],
* [[Git|https://git-scm.org/]] (most dependencies are accessible via Git only).

Make sure that the software is in your path, e.g. via:
```sh
export PATH=$PATH:/usr/local/go/bin
export PATH=$PATH:$(go env GOPATH)/bin
```

The internal build tool need the following software.
It can be installed / updated via the build tool itself: ``go run tools/devtools/devtools.go``.

Otherwise you can install the software by hand:

* [[shadow|https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/shadow]] via ``go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow@latest``,
* [[staticcheck|https://staticcheck.io/]] via ``go install honnef.co/go/tools/cmd/staticcheck@latest``,
* [[unparam|https://mvdan.cc/unparam]][^[[GitHub|https://github.com/mvdan/unparam]]] via ``go install mvdan.cc/unparam@latest``,

* [[govulncheck|https://golang.org/x/vuln/cmd/govulncheck]] via ``go install golang.org/x/vuln/cmd/govulncheck@latest``,

id: 20210916194900
title: Checklist for Release
role: zettel
syntax: zmk
created: 20210916194900
modified: 20231213194631

# Sync with the official repository
#* ``fossil sync -u``
# Make sure that there is no workspace defined.
#* ``ls ..`` must not have a file ''go.work'', in no parent folder.
# Make sure that all dependencies are up-to-date.
#* ``cat go.mod``
# Clean up your Go workspace:
#* ``go run tools/clean/clean.go`` (alternatively: ``make clean``).
# All internal tests must succeed:
#* ``go run tools/check/check.go -r`` (alternatively: ``make relcheck``).
# The API tests must succeed on every development platform:
#* ``go run tools/testapi/testapi.go`` (alternatively: ``make api``).
# Run [[linkchecker|https://linkchecker.github.io/linkchecker/]] with the manual:
#* ``go run -race cmd/zettelstore/main.go run -d docs/manual``
#* ``linkchecker http://127.0.0.1:23123 2>&1 | tee lc.txt``
#* Check all ""Error: 404 Not Found""
#* Check all ""Error: 403 Forbidden"": allowed for endpoint ''/p'' with encoding ''html'' for those zettel that are accessible only in ''expert-mode''.
#* Try to resolve other error messages and warnings
#* Warnings about empty content can be ignored
# On every development platform, the box with 10.000 zettel must run, with ''-race'' enabled:
#* ``go run -race cmd/zettelstore/main.go run -d DIR``.
# Create a development release:
#* ``go run tools/build.go release`` (alternatively: ``make release``).
# On every platform (esp. macOS), the box with 10.000 zettel must run properly:
#* ``./zettelstore -d DIR``
# Update files in directory ''www''
#* index.wiki
#* download.wiki
#* changes.wiki
#* plan.wiki
# Set file ''VERSION'' to the new release version.
  It _must_ consist of three digits: MAJOR.MINOR.PATCH, even if PATCH is zero
# Disable Fossil autosync mode:
#* ``fossil setting autosync off``
# Commit the new release version:
#* ``fossil commit --tag release --tag vVERSION -m "Version VERSION"``
#* **Important:** the tag must follow the given pattern, e.g. ''v0.0.15''.
   Otherwise client will not be able to import ''zettelkasten.de/z''.
# Clean up your Go workspace:
#* ``go run tools/clean/clean.go`` (alternatively: ``make clean``).
# Create the release:
#* ``go run tools/build/build.go release`` (alternatively: ``make release``).
# Remove previous executables:
#* ``fossil uv remove --glob '*-PREVVERSION*'``
# Add executables for release:
#* ``cd releases``
#* ``fossil uv add *.zip``
#* ``cd ..``
#* Synchronize with main repository:

This list is used to check the generated HTML code (''ZID'' is the paceholder for the zettel identification):

* Check all zettel HTML encodings, via the path ''/z/ZID?enc=html&part=zettel''
* Check all zettel web views, via the path ''/h/ZID''
* The info page of all zettel is checked, via path ''/i/ZID''
* A subset of max. 100 zettel will be checked for the validity of their edit page, via ''/e/ZID''
* 10 random zettel are checked for a valid create form, via ''/c/ZID''
* The zettel rename form will be checked for 100 zettel, via ''/b/ZID''
* A maximum of 200 random zettel are checked for a valid delete dialog, via ''/d/ZID''

Depending on the selected Zettelstore, the command might take a long time.

You can shorten the time, if you disable any zettel query in the footer.

=== Build

id: 00001000000000
title: Zettelstore Manual
role: manual
tags: #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20231125185455
show-back-links: false

* [[Introduction|00001001000000]]
* [[Design goals|00001002000000]]
* [[Installation|00001003000000]]
* [[Configuration|00001004000000]]
* [[Structure of Zettelstore|00001005000000]]
* [[Layout of a zettel|00001006000000]]
* [[Zettelmarkup|00001007000000]]
* [[Other markup languages|00001008000000]]
* [[Security|00001010000000]]
* [[API|00001012000000]]
* [[Web user interface|00001014000000]]
* [[Tips and Tricks|00001017000000]]
* [[Troubleshooting|00001018000000]]
* Frequently asked questions

Version: {{00001000000001}}.

Licensed under the EUPL-1.2-or-later.

id: 00001003000000
title: Installation of the Zettelstore software
role: manual
tags: #installation #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20220119145756

=== The curious user
You just want to check out the Zettelstore software

* Grab the appropriate executable and copy it into any directory
* Start the Zettelstore software, e.g. with a double click[^On Windows and macOS, the operating system tries to protect you from possible malicious software. If you encounter problem, please take a look on the [[Troubleshooting|00001018000000]] page.]

* A sub-directory ""zettel"" will be created in the directory where you put the executable.
  It will contain your future zettel.
* Open the URI [[http://localhost:23123]] with your web browser.
  It will present you a mostly empty Zettelstore.
  There will be a zettel titled ""[[Home|00010000000000]]"" that contains some helpful information.
* Please read the instructions for the [[web-based user interface|00001014000000]] and learn about the various ways to write zettel.
* If you restart your device, please make sure to start your Zettelstore again.

id: 00001003305000
title: Enable Zettelstore to start automatically on Windows
role: manual
tags: #installation #manual #zettelstore
syntax: zmk
created: 20211125191727
modified: 20220218125541

Windows is a complicated beast. There are several ways to automatically start Zettelstore.

=== Startup folder

One way is to use the [[autostart folder|https://support.microsoft.com/en-us/windows/add-an-app-to-run-automatically-at-startup-in-windows-10-150da165-dcd9-7230-517b-cf3c295d89dd]].
Open the folder where you have placed in the Explorer.

=== Task scheduler

The Windows Task scheduler allows you to start Zettelstore as an background task.

This is both an advantage and a disadvantage.

On the plus side, Zettelstore runs in the background, and it does not disturbs you.
All you have to do is to open your web browser, enter the appropriate URL, and there you go.

On the negative side, you will not be notified when you enter the wrong data in the Task scheduler and Zettelstore fails to start.
This can be mitigated by first using the command line prompt to start Zettelstore with the appropriate options.
Once everything works, you can register Zettelstore to be automatically started by the task scheduler.
There you should make sure that you have followed the first steps as described on the [[parent page|00001003300000]].

Create a new action.

{{00001003305112}}

The next steps are the trickiest.

If you did not created a startup configuration file, then create an action that starts a program.
Enter the file path where you placed the Zettelstore executable.
The ""Browse ..."" button helps you with that.[^I store my Zettelstore executable in the sub-directory ''bin'' of my home directory.]

It is essential that you also enter a directory, which serves as the environment for your zettelstore.
The (sub-) directory ''zettel'', which will contain your zettel, will be placed in this directory.
If you leave the field ""Start in (optional)"" empty, the directory will be an internal Windows system directory (most likely: ''C:\\Windows\\System32'').

id: 00001004010000
title: Zettelstore startup configuration
role: manual
tags: #configuration #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240710183532

The configuration file, specified by the ''-c CONFIGFILE'' [[command line option|00001004051000]], allows you to specify some startup options.
These cannot be stored in a [[configuration zettel|00001004020000]] because they are needed before Zettelstore can start or because of security reasons.
For example, Zettelstore needs to know in advance on which network address it must listen or where zettel are stored.
An attacker that is able to change the owner can do anything.
Therefore, only the owner of the computer on which Zettelstore runs can change this information.

: Specifies a [[box|00001004011200]] where zettel are stored.
  During startup, __X__ is incremented, starting with one, until no key is found.
  This allows to configuring than one box.

  If no ''box-uri-1'' key is given, the overall effect will be the same as if only ''box-uri-1'' was specified with the value ""dir://.zettel"".
  In this case, even a key ''box-uri-2'' will be ignored.
; [!debug-mode|''debug-mode'']
: If set to [[true|00001006030500]], allows to debug the Zettelstore software (mostly used by the developers).
  Disables any timeout values of the internal web server and does not send some security-related data.
  Sets [[''log-level''|#log-level]] to ""debug"".


  Do not enable it for a production server.

  Default: ""false""
; [!default-dir-box-type|''default-dir-box-type'']
: Specifies the default value for the (sub-)type of [[directory boxes|00001004011400#type]], in which Zettel are typically stored.

  Default: ""false""
; [!read-only-mode|''read-only-mode'']
: If set to a [[true value|00001006030500]] the Zettelstore service puts into a read-only mode.
  No changes are possible.

  Default: ""false"".





; [!secret|''secret'']
: A string value to make the communication with external clients strong enough so that sessions of the [[web user interface|00001014000000]] or [[API access token|00001010040700]] cannot be altered by some external unfriendly party.
  The string must have a length of at least 16 bytes.

  This value is only needed to be set if [[authentication is enabled|00001010040100]] by setting the key [[''owner''|#owner]] to some user identification value.
; [!token-lifetime-api|''token-lifetime-api''], [!token-lifetime-html|''token-lifetime-html'']
: Define lifetime of access tokens in minutes.

id: 00001004020000
title: Configure the running Zettelstore
role: manual
tags: #configuration #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20231126180829
show-back-links: false

You can configure a running Zettelstore by modifying the special zettel with the ID [[00000000000100]].
This zettel is called __configuration zettel__.
The following metadata keys change the appearance / behavior of Zettelstore.
Some of them can be overwritten in an [[user zettel|00001010040200]], a subset of those may be overwritten in zettel that is currently used.
See the full list of [[metadata that may be overwritten|00001004020200]].

  Use values according to the language definition of [[RFC-5646|https://tools.ietf.org/html/rfc5646]].
; [!max-transclusions|''max-transclusions'']
: Maximum number of indirect transclusion.
  This is used to avoid an exploding ""transclusion bomb"", a form of a [[billion laughs attack|https://en.wikipedia.org/wiki/Billion_laughs_attack]].

  Default: ""1024"".
; [!show-back-links|''show-back-links''], [!show-folge-links|''show-folge-links''], [!show-subordinate-links|''show-subordinate-links''], [!show-successor-links|''show-successor-links'']
: When displaying a zettel in the web user interface, references to other zettel are normally shown below the content of the zettel.
  This affects the metadata keys [[''back''|00001006020000#back]], [[''folge''|00001006020000#folge]], [[''subordinates''|00001006020000#subordinates]], and  [[''successors''|00001006020000#successors]].

  These configuration keys may be used to show, not to show, or to close the list of referenced zettel.

  Allowed values are: ""false"" (will not show the list), ""close"" (will show the list closed), and ""open"" / """" (will show the list).

  Default: """".

id: 00001004020200
title: Runtime configuration data that may be user specific or zettel specific
role: manual
tags: #configuration #manual #zettelstore
syntax: zmk
created: 20221205155521
modified: 20231126180752

Some metadata of the [[runtime configuration|00001004020000]] may be overwritten in an [[user zettel|00001010040200]].
A subset of those may be overwritten in zettel that is currently used.
This allows to specify user specific or zettel specific behavior.

The following metadata keys are supported to provide a more specific behavior:

|=Key|User:|Zettel:|Remarks
|[[''footer-zettel''|00001004020000#footer-zettel]]|Y|N|
|[[''home-zettel''|00001004020000#home-zettel]]|Y|N|
|[[''lang''|00001004020000#lang]]|Y|Y|Making it user-specific could make zettel for other user less useful
|[[''show-back-links''|00001004020000#show-back-links]]|Y|Y|
|[[''show-folge-links''|00001004020000#show-folge-links]]|Y|Y|
|[[''show-subordinate-links''|00001004020000#show-subordinate-links]]|Y|Y|
|[[''show-successor-links''|00001004020000#show-successor-links]]|Y|Y|

id: 00001005000000
title: Structure of Zettelstore
role: manual
tags: #design #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240710173506

Zettelstore is a software that manages your zettel.
Since every zettel must be readable without any special tool, most zettel has to be stored as ordinary files within specific directories.
Typically, file names and file content must comply to specific rules so that Zettelstore can manage them.
If you add, delete, or change zettel files with other tools, e.g. a text editor, Zettelstore will monitor these actions.

Zettelstore provides additional services to the user.
Via the builtin [[web user interface|00001014000000]] you can work with zettel in various ways.
For example, you are able to list zettel, to create new zettel, to edit them, or to delete them.
You can view zettel details and relations between zettel.

In addition, Zettelstore provides an ""application programming interface"" ([[API|00001012000000]]) that allows other software to communicate with the Zettelstore.
Zettelstore becomes extensible by external software.
For example, a more sophisticated user interface could be build, or an application for your mobile device that allows you to send content to your Zettelstore as new zettel.

=== Where zettel are stored

Your zettel are stored typically as files in a specific directory.
If you have not explicitly specified the directory, a default directory will be used.
The directory has to be specified at [[startup time|00001004010000]].
Nested directories are not supported (yet).

Every file in this directory that should be monitored by Zettelstore must have a file name that begins with 14 digits (0-9), the [[zettel identifier|00001006050000]].
If you create a new zettel via the [[web user interface|00001014000000]] or via the [[API|00001012053200]], the zettel identifier will be the timestamp of the current date and time (format is ''YYYYMMDDhhmmss'').
This allows zettel to be sorted naturally by creation time.[^Zettel identifier format will be migrated to a new format after version 0.19, without reference to the creation date. See [[Alphanumeric Zettel Identifier|00001006050200]] for some details.]

Since the only restriction on zettel identifiers are the 14 digits, you are free to use other digit sequences.[^Zettel identifier format will be migrated to a new format after version 0.19, without reference to the creation date.]
The [[configuration zettel|00001004020000]] is one prominent example, as well as these manual zettel.
You can create these special zettel identifiers either with the __rename__[^Renaming is deprecated als will be removed in version 0.19 or after.] function of Zettelstore or by manually renaming the underlying zettel files.

It is allowed that the file name contains other characters after the 14 digits.
These are ignored by Zettelstore.

Two filename extensions are used by Zettelstore:
# ''.zettel'' is a format that stores metadata and content together in one file,
# the empty file extension is used, when the content must be stored in its own file, e.g. image data;
  in this case, the filename just the 14 digits of the zettel identifier, and optional characters except the period ''"."''.  
Other filename extensions are used to determine the ""syntax"" of a zettel.
This allows to use other content within the Zettelstore, e.g. images or HTML templates.

For example, you want to store an important figure in the Zettelstore that is encoded as a ''.png'' file.
Since each zettel contains some metadata, e.g. the title of the figure, the question arises where these data should be stores.
The solution is a meta-file with the same zettel identifier, but without a filename extension.
Zettelstore recognizes this situation and reads in both files for the one zettel containing the figure.
It maintains this relationship as long as theses files exists.

In case of some textual zettel content you do not want to store the metadata and the zettel content in two different files.
Here the ''.zettel'' extension will signal that the metadata and the zettel content will be put in the same file, separated by an empty line or a line with three dashes (""''-\-\-''"", also known as ""YAML separator"").

=== Predefined zettel

Zettelstore contains some [[predefined zettel|00001005090000]] to work properly.

To allow changing predefined zettel, both the file store and the internal zettel store are internally chained together.
If you change a zettel, it will be always stored as a file.
If a zettel is requested, Zettelstore will first try to read that zettel from a file.
If such a file was not found, the internal zettel store is searched secondly.

Therefore, the file store ""shadows"" the internal zettel store.
If you want to read the original zettel, you either have to delete the zettel (which removes it from the file directory), or you have to rename[^Renaming is deprecated als will be removed in version 0.19 or after.] it to another zettel identifier.
Now we have two places where zettel are stored: in the specific directory and within the Zettelstore software.

* [[List of predefined zettel|00001005090000]]

=== Boxes: alternative ways to store zettel
As described above, a zettel may be stored as a file inside a directory or inside the Zettelstore software itself.
Zettelstore allows other ways to store zettel by providing an abstraction called __box__.[^Formerly, zettel were stored physically in boxes, often made of wood.]

id: 00001005090000
title: List of predefined zettel
role: manual
tags: #manual #reference #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240709180005

The following table lists all predefined zettel with their purpose.[^Zettel identifier format will be migrated to a new format after version 0.19.]





|= Identifier :|= Title | Purpose
| [[00000000000001]] | Zettelstore Version | Contains the version string of the running Zettelstore
| [[00000000000002]] | Zettelstore Host | Contains the name of the computer running the Zettelstore
| [[00000000000003]] | Zettelstore Operating System | Contains the operating system and CPU architecture of the computer running the Zettelstore
| [[00000000000004]] | Zettelstore License | Lists the license of Zettelstore
| [[00000000000005]] | Zettelstore Contributors | Lists all contributors of Zettelstore
| [[00000000000006]] | Zettelstore Dependencies | Lists all licensed content
| [[00000000000007]] | Zettelstore Log | Lists the last 8192 log messages
| [[00000000000008]] | Zettelstore Memory | Some statistics about main memory usage
| [[00000000000009]] | Zettelstore Sx Engine | Statistics about the [[Sx|https://t73f.de/r/sx]] engine, which interprets symbolic expressions
| [[00000000000020]] | Zettelstore Box Manager | Contains some statistics about zettel boxes and the the index process
| [[00000000000090]] | Zettelstore Supported Metadata Keys | Contains all supported metadata keys, their [[types|00001006030000]], and more
| [[00000000000092]] | Zettelstore Supported Parser | Lists all supported values for metadata [[syntax|00001006020000#syntax]] that are recognized by Zettelstore
| [[00000000000096]] | Zettelstore Startup Configuration | Contains the effective values of the [[startup configuration|00001004010000]]
| [[00000000000100]] | Zettelstore Runtime Configuration | Allows to [[configure Zettelstore at runtime|00001004020000]]
| [[00000000000102]] | Zettelstore Warnings | Warnings about potential problematic zettel identifier
| [[00000000010100]] | Zettelstore Base HTML Template | Contains the general layout of the HTML view
| [[00000000010200]] | Zettelstore Login Form HTML Template | Layout of the login form, when authentication is [[enabled|00001010040100]]
| [[00000000010300]] | Zettelstore List Zettel HTML Template | Used when displaying a list of zettel
| [[00000000010401]] | Zettelstore Detail HTML Template | Layout for the HTML detail view of one zettel
| [[00000000010402]] | Zettelstore Info HTML Template | Layout for the information view of a specific zettel
| [[00000000010403]] | Zettelstore Form HTML Template | Form that is used to create a new or to change an existing zettel that contains text
| [[00000000010404]] | Zettelstore Rename Form HTML Template | View that is displayed to change the [[zettel identifier|00001006050000]]
| [[00000000010405]] | Zettelstore Delete HTML Template | View to confirm the deletion of a zettel
| [[00000000010700]] | Zettelstore Error HTML Template | View to show an error message
| [[00000000019000]] | Zettelstore Sxn Start Code | Starting point of sxn functions to build the templates
| [[00000000019990]] | Zettelstore Sxn Base Code | Base sxn functions to build the templates
| [[00000000020001]] | Zettelstore Base CSS | System-defined CSS file that is included by the [[Base HTML Template|00000000010100]]
| [[00000000025001]] | Zettelstore User CSS | User-defined CSS file that is included by the [[Base HTML Template|00000000010100]]
| [[00000000040001]] | Generic Emoji | Image that is shown if [[original image reference|00001007040322]] is invalid
| [[00000000060010]] | zettel | [[Role zettel|00001012051800]] for the role ""[[zettel|00001006020100#zettel]]""
| [[00000000060020]] | confguration | [[Role zettel|00001012051800]] for the role ""[[confguration|00001006020100#confguration]]""
| [[00000000060030]] | role | [[Role zettel|00001012051800]] for the role ""[[role|00001006020100#role]]""
| [[00000000060040]] | tag | [[Role zettel|00001012051800]] for the role ""[[tag|00001006020100#tag]]""

| [[00000000090000]] | New Menu | Contains items that should be in the zettel template menu
| [[00000000090001]] | New Zettel | Template for a new zettel with role ""[[zettel|00001006020100#zettel]]""
| [[00000000090002]] | New User | Template for a new [[user zettel|00001010040200]]
| [[00000000090003]] | New Tag | Template for a new [[tag zettel|00001006020100#tag]]
| [[00000000090004]] | New Role | Template for a new [[role zettel|00001006020100#role]]
| [[00009999999998]] | Zettelstore Application Directory | Maps application name to application specific zettel
| [[00010000000000]] | Home | Default home zettel, contains some welcome information

If a zettel is not linked, it is not accessible for the current user.
In most cases, you must at least enable [[''expert-mode''|00001004020000#expert-mode]].

**Important:** All identifier may change until a stable version of the software is released.

id: 00001006020000
title: Supported Metadata Keys
role: manual
tags: #manual #meta #reference #zettel #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240708154737

Although you are free to define your own metadata, by using any key (according to the [[syntax|00001006010000]]), some keys have a special meaning that is enforced by Zettelstore.
See the [[computed list of supported metadata keys|00000000000090]] for details.

Most keys conform to a [[type|00001006030000]].

; [!author|''author'']

; [!precursor|''precursor'']
: References zettel for which this zettel is a ""Folgezettel"" / follow-up zettel.
  Basically the inverse of key [[''folge''|#folge]].
; [!predecessor|''predecessor'']
: References the zettel that contains a previous version of the content.
  In contrast to [[''precursor''|#precurso]] / [[''folge''|#folge]], this is a reference because of technical reasons, not because of content-related reasons.
  Basically the inverse of key [[''successors''|#successors]].



; [!published|''published'']
: This property contains the timestamp of the mast modification / creation of the zettel.
  If [[''modified''|#modified]] is set with a valid timestamp, it contains the its value.
  Otherwise, if [[''created''|#created]] is set with a valid timestamp, it contains the its value.
  Otherwise, if the zettel identifier contains a valid timestamp, the identifier is used.
  In all other cases, this property is not set.

: Marks a zettel as read-only.
  The interpretation of [[supported values|00001006020400]] for this key depends, whether authentication is [[enabled|00001010040100]] or not.
; [!role|''role'']
: Defines the role of the zettel.
  Can be used for selecting zettel.
  See [[supported zettel roles|00001006020100]].
  If not given, it is ignored.
; [!subordinates|''subordinates'']
: Is a property that contains identifier of all zettel that reference this zettel through the [[''superior''|#superior]] value.
; [!successors|''successors'']
: Is a property that contains identifier of all zettel that reference this zettel through the [[''predecessor''|#predecessor]] value.
  Therefore, it references all zettel that contain a new version of the content and/or metadata.
  In contrast to [[''folge''|#folge]], these are references because of technical reasons, not because of content-related reasons.
  In most cases, zettel referencing the current zettel should be updated to reference a successor zettel.
  The [[query reference|00001007040310]] [[query:backward? successors?]] lists all such zettel.
; [!summary|''summary'']
: Summarizes the content of the zettel.
  You may use all [[inline-structued elements|00001007040000]] of Zettelmarkup.
; [!superior|''superior'']
: Specifies a zettel that is conceptually a superior zettel.
  This might be a more abstract zettel, or a zettel that should be higher in a hierarchy.
; [!syntax|''syntax'']
: Specifies the syntax that should be used for interpreting the zettel.
  The zettel about [[other markup languages|00001008000000]] defines supported values.
  If it is not given, it defaults to ''plain''.
; [!tags|''tags'']
: Contains a space separated list of tags to describe the zettel further.
  Each Tag must begin with the number sign character (""''#''"", U+0023).
; [!title|''title'']
: Specifies the title of the zettel.
  If not given, the value of [[''id''|#id]] will be used.
; [!url|''url'']
: Defines an URL / URI for this zettel that possibly references external material.
  One use case is to specify the document that the current zettel comments on.
  The URL will be rendered special in the [[web user interface|00001014000000]] if you use the default template.
; [!useless-files|''useless-files'']
: Contains the file names that are rejected to serve the content of a zettel.
  Is used for [[directory boxes|00001004011400]] and [[file boxes|00001004011200#file]].
  If a zettel is renamed[^Renaming a zettel is deprecated. This feature will be removed in version 0.19 or later.] or deleted, these files will be deleted.
; [!user-id|''user-id'']
: Provides some unique user identification for an [[user zettel|00001010040200]].
  It is used as a user name for authentication.

  It is only used for zettel with a ''role'' value of ""user"".
; [!user-role|''user-role'']
: Defines the basic privileges of an authenticated user, e.g. reading / changing zettel.

id: 00001006050000
title: Zettel identifier
role: manual
tags: #design #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240708154551

Each zettel is given a unique identifier.
To some degree, the zettel identifier is part of the metadata.
Basically, the identifier is given by the [[Zettelstore|00001005000000]] software.

=== Timestamp-based identifier

Every zettel identifier consists of 14 digits.
They resemble a timestamp: the first four digits could represent the year, the
next two represent the month, following by day, hour, minute, and second.[^Zettel identifier format will be migrated to a new format after version 0.19, without reference to the creation date.]

This allows to order zettel chronologically in a canonical way.

In most cases the zettel identifier is the timestamp when the zettel was created.

However, the Zettelstore software just checks for exactly 14 digits.
Anybody is free to assign a ""non-timestamp"" identifier to a zettel, e.g. with
a month part of ""35"" or with ""99"" as the last two digits.

Some zettel identifier are [[reserved|00001006055000]] and should not be used otherwise.
All identifiers of zettel initially provided by an empty Zettelstore begin with ""000000"", except the home zettel ''00010000000000''.
Zettel identifier of this manual have be chosen to begin with ""000010"".

A zettel can have any identifier that contains 14 digits and that is not in use
by another zettel managed by the same Zettelstore.

=== Identifiers with four alphanumeric characters
In the future, above identifier format will change.
The migration to the new format starts with Zettelstore version 0.18 and will last approximately until version 0.22.

Above described format of 14 digits will be changed to four alphanumeric characters, i.e. the digits ''0'' to ''9'', and the letters ''a'' to ''z''.
You might note that using 14 digits you are allowed a little less than 10^^14^^ Zettel, i.e. more than 999 trillion zettel, while the new scheme only allows you to create 36^^4^^-1 zettel (1679615 zettel, to be exact).
Since Zettelstore is a single-user system, more than a million zettel should be enough.
However, there must be a way to replace an identifier with 14 digits by an identifier with four characters.

As a first step, the list of [[reserved zettel identifier|00001006055000]] is updated, as well as ways of client software to use predefined identifier.

id: 00001006050200
title: Alphanumeric Zettel Identifier
role: manual
tags: #design #manual #zettelstore
syntax: zmk
created: 20240705200557
modified: 20240710173133
precursor: 00001006050000

Timestamp-based zettel identifier (14 digits) will be migrated to a new format.
Instead of using the current date and time of zettel creation, the new format is based in incrementing zettel identifier.
When creating a new zettel, its identifier is calculated by adding one to the current maximum zettel identifier.
The external representation if the new format identifier is a sequence of four alphanumeric characters, i.e. the 36
characters ''0'' … ''9'', and ''a'' … ''z''.
The external representation is basically a ""base-36"" encoding of the number.

The characters ''A'' … ''Z'' are mapped to the lower-case ''a'' … ''z''.

=== Migration process
Please note: the following is just a plan.
Plans tend to be revised if they get in contact with reality.

; Version 0.18
: Provides some tools to check your own zettelstore for problematic zettel identifier.
  For example, zettel without metadata key ''created'' should be updated by the user, especially if the zettel identifier is below ''19700101000000''.
  Most likely, this is the case for zettel created before version 0.7 (2022-08-17).

  Zettel [[Zettelstore Warnings|00000000000102]] (''00000000000102'') lists these problematic zettel identifier.[^Only visible in [[expert mode|00001004020000#expert-mode]].]
  You should update your zettel to remove these warnings to ensure a smooth migration.

  If you have developed an application, that defines a specific zettel identifier to be used as application configuration, you should must the new zettel [[Zettelstore Application Directory|00009999999998]] (''00009999999998'').

  There is an explicit, but preliminary mapping of the old format to the new one, and vice versa.
  This mapping will be calculated with the order of the identifier in the old format.
  The zettel [[Zettelstore Identifier Mapping|00009999999999]] (''00009999999999'') will show this mapping.[^Only visible in [[expert mode|00001004020000#expert-mode]].]

; Version 0.19
: The new identifier format will be used initially internal.
  The old format with 14 digits is still used to create URIs and to link zettel.

  You will have some time to update your zettel data if you detect some issues.

  Operation to rename a zettel, i.e. assigning a new identifier to a zettel, is remove permanently.
; Version 0.20
: The internal search index is based on the new format identifier.
; Version 0.21
: The new format is used to calculate URIs and to form links.
; Version 0.22
: Old format identifier are full legacy.

id: 00001006055000
title: Reserved zettel identifier
role: manual
tags: #design #manual #zettelstore
syntax: zmk
created: 20210721105704
modified: 20240708154858

[[Zettel identifier|00001006050000]] are typically created by examine the current date and time.
By renaming[^The rename operation id deprecated and will be removed in version 0.19 or later.] a zettel, you are able to provide any sequence of 14 digits[^Zettel identifier format will be migrated to a new format after version 0.19.].
If no other zettel has the same identifier, you are allowed to rename a zettel.

To make things easier, you must not use zettel identifier that begin with four zeroes (''0000'').

All zettel provided by an empty zettelstore begin with six zeroes[^Exception: the predefined home zettel ''00010000000000''. But you can [[configure|00001004020000#home-zettel]] another zettel with another identifier as the new home zettel.].
Zettel identifier of this manual have be chosen to begin with ''000010''.

However, some external applications may need at least one defined zettel identifier to work properly.
Zettel [[Zettelstore Application Directory|00009999999998]] (''00009999999998'') can be used to associate a name to a zettel identifier.
For example, if your application is named ""app"", you create a metadata key ''app-zid''.
Its value is the zettel identifier of the zettel that configures your application.

=== Reserved Zettel Identifier

|= From | To | Description
| 00000000000000 | 0000000000000 | This is an invalid zettel identifier
| 00000000000001 | 0000099999999 | [[Predefined zettel|00001005090000]]
| 00001000000000 | 0000109999999 | This [[Zettelstore manual|00001000000000]]
| 00001100000000 | 0000899999999 | Reserved, do not use.
| 00009000000000 | 0000999999999 | Reserved for applications (legacy)

Since the format of zettel identifier will change in the near future, no external application is allowed to use the range ''00000000000001'' … ''0000999999999''.

==== External Applications (Legacy)
|= From | To | Description
| 00009000001000 | 00009000001999 | [[Zettel Presenter|https://zettelstore.de/contrib]], an application to display zettel as a HTML-based slideshow

id: 00001007000000
title: Zettelmarkup
role: manual
tags: #manual #zettelmarkup #zettelstore
syntax: zmk
created: 20210126175322
modified: 20221209192105

Zettelmarkup is a rich plain-text based markup language for writing zettel content.
Besides the zettel content, Zettelmarkup is also used for specifying the title of a zettel, regardless of the syntax of a zettel.

Zettelmarkup supports the longevity of stored notes by providing a syntax that any person can easily read, as well as a computer.
Zettelmarkup can be much easier parsed / consumed by a software compared to other markup languages.
Writing a parser for [[Markdown|https://daringfireball.net/projects/markdown/syntax]] is quite challenging.
[[CommonMark|00001008010500]] is an attempt to make it simpler by providing a comprehensive specification, combined with an extra chapter to give hints for the implementation.
Zettelmarkup follows some simple principles that anybody who knows to ho write software should be able understand to create an implementation.

Zettelmarkup is a markup language on its own.
This is in contrast to Markdown, which is basically a super-set of HTML: every HTML document is a valid Markdown document.[^To be precise: the content of the ``<body>`` of each HTML document is a valid Markdown document.]
While HTML is a markup language that will probably last for a long time, it cannot be easily translated to other formats, such as PDF, JSON, or LaTeX.
Additionally, it is allowed to embed other languages into HTML, such as CSS or even JavaScript.
This could create problems with longevity as well as security problems.

id: 00001007010000
title: Zettelmarkup: General Principles
role: manual
tags: #manual #zettelmarkup #zettelstore
syntax: zmk
created: 20210126175322
modified: 20211124175047

Any document can be thought as a sequence of paragraphs and other [[block-structured elements|00001007030000]] (""blocks""), such as [[headings|00001007030300]], [[lists|00001007030200]], quotations, and code blocks.
Some of these blocks can contain other blocks, for example lists may contain other lists or paragraphs.
Other blocks contain [[inline-structured elements|00001007040000]] (""inlines""), such as text, [[links|00001007040310]], emphasized text, and images.

With the exception of lists and tables, the markup for blocks always begins at the first position of a line with three or more identical characters.
List blocks also begin at the first position of a line, but may need one or more identical character, plus a space character.

Many block and inline elements can be refined by additional [[attributes|00001007050000]].
Attributes resemble roughly HTML attributes and are put near the corresponding elements by using the syntax ``{...}``{=zmk}.
One example is to make space characters visible inside a inline literal element: ``1 + 2 = 3``{-} was specified by using the default attribute: ``\`\`1 + 2 = 3\`\`{-}``.

To summarize:

* With some exceptions, blocks-structural elements begins at the for position of a line with three identical characters.
* The most important exception to this rule is the specification of lists.
* If no block element is found, a paragraph with inline elements is assumed.
* With some exceptions, inline-structural elements begins with two characters, quite often the same two characters.
* The most important exceptions are links.
* The backslash character can help to resolve possible ambiguities.
* Attributes refine some block and inline elements.
* Block elements have a higher priority than inline elements.

These principles makes automatic recognizing zettelmarkup an (relatively) easy task.
By looking at the reference implementation, a moderately skilled software developer should be able to create a appropriate software in a different programming language.

id: 00001007030000
title: Zettelmarkup: Block-Structured Elements
role: manual
tags: #manual #zettelmarkup #zettelstore
syntax: zmk
created: 20210126175322
modified: 20220311181036

Every markup for blocks-structured elements (""blocks"") begins at the very first position of a line.

There are five kinds of blocks: lists, one-line blocks, line-range blocks, tables, and paragraphs.

=== Lists

:::example
= Heading
Some text follows.
:::
This is because headings need at least three equal sign character.

A paragraph is essentially a sequence of [[inline-structured elements|00001007040000]].
Inline-structured elements cam span more than one line.
Paragraphs are separated by empty lines.

If you want to specify a second paragraph inside a list item, or if you want to continue a paragraph on a second and more line within a list item, you must begin the paragraph with a certain number of space characters.
The number of space characters depends on the kind of a list and the relevant nesting level.

A line that begins with a space character and which is outside of a list or does not contain the right number of space characters is considered to be part of a paragraph.

id: 00001007030200
title: Zettelmarkup: Nested Lists
role: manual
tags: #manual #zettelmarkup #zettelstore
syntax: zmk
created: 20210126175322
modified: 20220218133902

There are thee kinds of lists that can be nested: ordered lists, unordered lists, and quotation lists.

Ordered lists are specified with the number sign (""''#''"", U+0023), unordered lists use the asterisk (""''*''"", U+002A), and quotation lists are specified with the greater-than sing (""''>''"", U+003E).
Let's call these three characters __list characters__.

Any nested list item is specified by a non-empty sequence of list characters, followed by a space character and a sequence of [[inline elements|00001007040000]].
In case of a quotation list as the last list character, the space character followed by a sequence of inline elements is optional.
The number / count of list characters gives the nesting of the lists.
If the following lines should also be part of the list item, exactly the same number of spaces must be given at the beginning of each of the following lines as it is the lists are nested, plus one additional space character.
In other words: the inline elements must begin at the same column as it was on the previous line.

The resulting sequence on inline elements is merged into a paragraph.
Appropriately indented paragraphs can specified after the first one.
Since each blocks-structured element has to be specified at the first position of a line, none of the nested list items may contain anything else than paragraphs.

Some examples:
```zmk
# One
# Two
# Three

id: 00001007031000
title: Zettelmarkup: Tables
role: manual
tags: #manual #zettelmarkup #zettelstore
syntax: zmk
created: 20210126175322
modified: 20220218131107

Tables are used to show some data in a two-dimensional fashion.
In zettelmarkup, table are not specified explicitly, but by entering __table rows__.
Therefore, a table can be seen as a sequence of table rows.
A table row is nothing as a sequence of __table cells__.
The length of a table is the number of table rows, the width of a table is the maximum length of its rows.

The first cell of a row must begin with the vertical bar character (""''|''"", U+007C) at the first position of a line.
The other cells of a row begin with the same vertical bar character at later positions in that line.
A cell is delimited by the vertical bar character of the next cell or by the end of the current line.
A vertical bar character as the last character of a line will not result in a table cell.
It will be ignored.

id: 00001007031140
title: Zettelmarkup: Query Transclusion
role: manual
tags: #manual #search #zettelmarkup #zettelstore
syntax: zmk
created: 20220809132350
modified: 20240219161800

A query transclusion is specified by the following sequence, starting at the first position in a line: ''{{{query:query-expression}}}''.
The line must literally start with the sequence ''{{{query:''.
Everything after this prefix is interpreted as a [[query expression|00001007700000]].

When evaluated, the query expression is evaluated, often resulting in a list of [[links|00001007040310]] to zettel, matching the query expression.
The result replaces the query transclusion element.

: The resulting list will be a numbered list.
; ''MINn'' (parameter)
: Emit only those values with at least __n__ aggregated values.
  __n__ must be a positive integer, ''MIN'' must be given in upper-case letters.
; ''MAXn'' (parameter)
: Emit only those values with at most __n__ aggregated values.
  __n__ must be a positive integer, ''MAX'' must be given in upper-case letters.
; ''TITLE'' (parameter)
: All words following ''TITLE'' are joined together to form a title.
  It is used for the ''ATOM'' and ''RSS'' action.
; ''ATOM'' (aggregate)
: Transform the zettel list into an [[Atom 1.0|https://www.rfc-editor.org/rfc/rfc4287]]-conformant document / feed.
  The document is embedded into the referencing zettel.
; ''RSS'' (aggregate)
: Transform the zettel list into a [[RSS 2.0|https://www.rssboard.org/rss-specification]]-conformant document / feed.
  The document is embedded into the referencing zettel.
; ''KEYS'' (aggregate)
: Emit a list of all metadata keys, together with the number of zettel having the key.
; ''REDIRECT'', ''REINDEX'' (aggregate)
: Will be ignored.
  These actions may have been copied from an existing [[API query call|00001012051400]] (or from a WebUI query), but are here superfluous (and possibly harmful).
; Any [[metadata key|00001006020000]] of type [[Word|00001006035500]] or of type [[TagSet|00001006034000]] (aggregates)
: Emit an aggregate of the given metadata key.

id: 00001007040322
title: Zettelmarkup: Image Embedding
role: manual
tags: #manual #zettelmarkup #zettelstore
syntax: zmk
created: 20210811154251
modified: 20221112111054

Image content is assumed, if an URL is used or if the referenced zettel contains an image.

Supported formats are:

* Portable Network Graphics (""PNG""), as defined by [[RFC\ 2083|https://tools.ietf.org/html/rfc2083]].
* Graphics Interchange Format (""GIF"), as defined by [[https://www.w3.org/Graphics/GIF/spec-gif89a.txt]].
* JPEG / JPG, defined by the __Joint Photographic Experts Group__.
* Scalable Vector Graphics (SVG), defined by [[https://www.w3.org/Graphics/SVG/]]
* WebP, defined by [[Google|https://developers.google.com/speed/webp]]

If the text is given, it will be interpreted as an alternative textual representation, to help persons with some visual disabilities.

[[Attributes|00001007050000]] are supported.
They must follow the last right curly bracket character immediately.
One prominent example is to specify an explicit title attribute that is shown on certain web browsers when the zettel is rendered in HTML:

Examples:
* [!spin|``{{Spinning Emoji|00000000040001}}{title=Emoji width=30}``] is rendered as ::{{Spinning Emoji|00000000040001}}{title=Emoji width=30}::{=example}.
* The above image is also the placeholder for a non-existent zettel:

** ``{{00000000009999}}`` will be rendered as ::{{00000000009999}}::{=example}.

id: 00001007720300
title: Query: Context Directive
role: manual
tags: #manual #search #zettelstore
syntax: zmk
created: 20230707204706
modified: 20240209191045

A context directive calculates the __context__ of a list of zettel identifier.
It starts with the keyword ''CONTEXT''.

Optionally you may specify some context details, after the keyword ''CONTEXT'', separated by space characters.
These are:
* ''FULL'': additionally search for zettel with the same tags,
* ''BACKWARD'': search for context only though backward links,
* ''FORWARD'': search for context only through forward links,
* ''COST'': one or more space characters, and a positive integer: set the maximum __cost__ (default: 17),
* ''MAX'': one or more space characters, and a positive integer: set the maximum number of context zettel (default: 200).

If no ''BACKWARD'' and ''FORWARD'' is specified, a search for context zettel will be done though backward and forward links.

The cost of a context zettel is calculated iteratively:
* Each of the specified zettel hast a cost of one.
* A zettel found as a single folge zettel or single precursor zettel has the cost of the originating zettel, plus one.
* A zettel found as a single subordinate zettel or single superior zettel has the cost of the originating zettel, plus 1.2.
* A zettel found as a single successor zettel or single predecessor zettel has the cost of the originating zettel, plus seven.
* A zettel found via another link without being part of a [[set of zettel identifier|00001006032500]], has the cost of the originating zettel, plus two.
* A zettel which is part of a set of zettel identifier, has the cost of the originating zettel, plus one of the four choices above and multiplied with roughly a linear-logarithmic value based on the size of the set.
* A zettel with the same tag, has the cost of the originating zettel, plus a linear-logarithmic number based on the number of zettel with this tag.
  If a zettel belongs to more than one tag compared with the current zettel, there is a discount of 90% per additional tag.
  This only applies if the ''FULL'' directive was specified.

id: 00001007780000
title: Formal syntax of query expressions
role: manual
tags: #manual #reference #search #zettelstore
syntax: zmk
created: 20220810144539
modified: 20240219155949

```
QueryExpression   := ZettelList? QueryDirective* SearchExpression ActionExpression?
ZettelList        := (ZID (SPACE+ ZID)*).
ZID               := '0'+ ('1' .. '9'') DIGIT*
                   | ('1' .. '9') DIGIT*.
QueryDirective    := ContextDirective

                   | ('!')? ('~' | ':' | '[' | '}').
ExistOperator     := '?'
                   | '!' '?'.
PosInt            := '0'
                   | ('1' .. '9') DIGIT*.
ActionExpression  := '|' (Word (SPACE+ Word)*)?
Action            := Word
                   | 'ATOM'
                   | 'KEYS'
                   | 'N' NO-SPACE*
                   | 'MAX' PosInt
                   | 'MIN' PosInt
                   | 'REDIRECT'
                   | 'REINDEX'
                   | 'RSS'
                   | 'TITLE' (SPACE Word)* .
Word              := NO-SPACE NO-SPACE*
```

id: 00001007800000
title: Zettelmarkup: Summary of Formatting Characters
role: manual
tags: #manual #reference #zettelmarkup #zettelstore
syntax: zmk
created: 20210126175322
modified: 20231113191330

The following table gives an overview about the use of all characters that begin a markup element.

|= Character :|= [[Blocks|00001007030000]] <|= [[Inlines|00001007040000]] <
| ''!''  | (free) | (free)
| ''"''  | [[Verse block|00001007030700]] | [[Short inline quote|00001007040100]]
| ''#''  | [[Ordered list|00001007030200]] | [[marked / highlighted text|00001007040100]]
| ''$''  | (reserved) | (reserved)
| ''%''  | [[Comment block|00001007030900]] | [[Comment|00001007040000]]
| ''&''  | (free) | [[Entity|00001007040000]]
| ''\'''  | (free)  | [[Computer input|00001007040200]]
| ''(''  | (free) | (free)
| '')''  | (free) | (free)
| ''*''  | [[Unordered list|00001007030200]] | [[strongly emphasized text|00001007040100]]
| ''+''  | (free) | (free)
| '',''  | (free) | [[Sub-scripted text|00001007040100]]
| ''-''  | [[Horizontal rule|00001007030400]] | ""[[en-dash|00001007040000]]""
| ''.''  | (free) | (free)
| ''/''  | (free) | (free)
| '':''  | [[Region block|00001007030800]] / [[description text|00001007030100]] | [[Inline region|00001007040100]]
| '';''  | [[Description term|00001007030100]] | (free)
| ''<''  | [[Quotation block|00001007030600]] | (free)

id: 00001010000000
title: Security
role: manual
tags: #configuration #manual #security #zettelstore
syntax: zmk
created: 20210126175322
modified: 20221018123622

Your zettel could contain sensitive content.
You probably want to ensure that only authorized person can read and/or modify them.
Zettelstore ensures this in various ways.

=== Local first
The Zettelstore is designed to run on your local computer.
If you do not configure it in other ways, no person from another computer can connect to your Zettelstore.
You must explicitly configure it to allow access from other computers.

In the case that you own multiple computers, you do not have to access the Zettelstore remotely.
You could install Zettelstore on each computer and set-up some software to synchronize your zettel.
Since zettel are stored as ordinary files, this task could be done in various ways.

=== Read-only
You can start the Zettelstore in an read-only mode.
Nobody, not even you as the owner of the Zettelstore, can change something via its interfaces[^However, as an owner, you have access to the files that store the zettel. If you modify the files, these changes will be reflected via its interfaces.].

You enable read-only mode through the key ''readonly'' in the [[startup configuration zettel|00001004010000#readonly]] or with the ''-r'' option of the ``zettelstore run`` sub-command.

=== Authentication
The Zettelstore can be configured that a user must authenticate itself to gain access to the content.

* [[How to enable authentication|00001010040100]]
* [[How to add a new user|00001010040200]]
* [[How users are authenticated|00001010040400]] (some technical background)
* [[Authenticated sessions|00001010040700]]

=== Authorization

id: 00001010040700
title: Access token
role: manual
tags: #authentication #configuration #manual #security #zettelstore
syntax: zmk
created: 20210126175322
modified: 20211202120950

If an user is authenticated, an ""access token"" is created that must be sent with every request to prove the identity of the caller.
Otherwise the user will not be recognized by Zettelstore.

If the user was authenticated via the [[web user interface|00001014000000]], the access token is stored in a [[""session cookie""|https://en.wikipedia.org/wiki/HTTP_cookie#Session_cookie]].
When the web browser is closed, theses cookies are not saved.
If you want web browser to store the cookie as long as lifetime of that token, the owner must set ''persistent-cookie'' of the [[startup configuration|00001004010000]] to ''true''.

If the web browser remains inactive for a period, the user will be automatically logged off, because each access token has a limited lifetime.
The maximum length of this period is specified by the ''token-lifetime-html'' value of the startup configuration.
Every time a web page is displayed, a fresh token is created and stored inside the cookie.

If the user was authenticated via the API, the access token will be returned as the content of the response.
Typically, the lifetime of this token is more short term, e.g. 10 minutes.
It is specified by the ''token-lifetime-api'' value of the startup configuration.
If you need more time, you can either [[re-authenticate|00001012050200]] the user or use an API call to [[renew the access token|00001012050400]].

If you remotely access your Zettelstore via HTTP (not via HTTPS, which allows encrypted communication), your must set the ''insecure-cookie'' value of the startup configuration to ''true''.
In most cases, such a scenario is not recommended, because user name and password will be transferred as plain text.
You could make use of such scenario if you know all parties that access the local network where you access the Zettelstore.

id: 00001010070600
title: Access rules
role: manual
tags: #authorization #configuration #manual #security #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240708154954

Whether an operation of the Zettelstore is allowed or rejected, depends on various factors.

The following rules are checked first, in this order:

# In read-only mode, every operation except the ""Read"" operation is rejected.
# If there is no owner, authentication is disabled and every operation is allowed for everybody.

** If the zettel is the [[user zettel|00001010040200]] of the authenticated user, proceed as follows:
*** If some sensitive meta values are changed (e.g. user identifier, zettel role, user role, but not hashed password), reject the access
*** Since the user just updates some uncritical values, grant the access
   In other words: a user is allowed to change its user zettel, even if s/he has no writer privilege and if only uncritical data is changed.
** If the ''user-role'' of the user is ""reader"", reject the access.
** If the user is not allowed to create a new zettel, reject the access.
** Otherwise grant the access.
* Rename a zettel[^Renaming is deprecated. This operation will be removed in version 0.19 or later.]
** Reject the access.
   Only the owner of the Zettelstore is currently allowed to give a new identifier for a zettel.
* Delete a zettel
** Reject the access.
   Only the owner of the Zettelstore is allowed to delete a zettel.
   This may change in the future.

id: 00001012000000
title: API
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240708154140

The API (short for ""**A**pplication **P**rogramming **I**nterface"") is the primary way to communicate with a running Zettelstore.
Most integration with other systems and services is done through the API.
The [[web user interface|00001014000000]] is just an alternative, secondary way of interacting with a Zettelstore.

=== Background
The API is HTTP-based and uses plain text and [[symbolic expressions|00001012930000]] as its main encoding formats for exchanging messages between a Zettelstore and its client software.

=== Working with zettel
* [[Create a new zettel|00001012053200]]
* [[Retrieve metadata and content of an existing zettel|00001012053300]]
* [[Retrieve metadata of an existing zettel|00001012053400]]
* [[Retrieve evaluated metadata and content of an existing zettel in various encodings|00001012053500]]
* [[Retrieve parsed metadata and content of an existing zettel in various encodings|00001012053600]]
* [[Update metadata and content of a zettel|00001012054200]]
* [[Rename a zettel|00001012054400]] (deprecated)
* [[Delete a zettel|00001012054600]]

=== Various helper methods
* [[Retrieve administrative data|00001012070500]]
* [[Execute some commands|00001012080100]]
** [[Check for authentication|00001012080200]]
** [[Refresh internal data|00001012080500]]

id: 00001012051200
title: API: List all zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20230807170810

To list all zettel just send a HTTP GET request to the [[endpoint|00001012920000]] ''/z''[^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header].
Always use the endpoint ''/z'' to work with a list of zettel.

Without further specifications, a plain text document is returned, with one line per zettel.
Each line contains in the first 14 characters the [[zettel identifier|00001006050000]].
Separated by a space character, the title of the zettel follows:

```sh

id: 00001012051400
title: API: Query the list of all zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20220912111111
modified: 20240711161320
precursor: 00001012051200

The [[endpoint|00001012920000]] ''/z'' also allows you to filter the list of all zettel[^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header] and optionally to provide some actions.

A [[query|00001007700000]] is an optional [[search expression|00001007700000#search-expression]], together with an optional [[list of actions|00001007700000#action-list]] (described below).
An empty search expression will select all zettel.
An empty list of action, or no valid action, returns the list of all selected zettel metadata.

Search expression and action list are separated by a vertical bar character (""''|''"", U+007C), and must be given with the query parameter ''q''.

id: 00001012053300
title: API: Retrieve metadata and content of an existing zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20211004093206
modified: 20230807170259

The [[endpoint|00001012920000]] to work with metadata and content of a specific zettel is ''/z/{ID}'', where ''{ID}'' is a placeholder for the [[zettel identifier|00001006050000]].

For example, to retrieve some data about this zettel you are currently viewing, just send a HTTP GET request to the endpoint ''/z/00001012053300''[^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header].

````sh
# curl 'http://127.0.0.1:23123/z/00001012053300'
The [[endpoint|00001012920000]] to work with metadata and content of a specific zettel is ''/z/{ID}'', where ''{ID}'' is a placeholder for the [[zettel identifier|00001006050000]].

For example, to retrieve some data about this zettel you are currently viewing, just send a HTTP GET request to the endpoint ''/z/00001012053300''[^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header].

```sh
...
````

Optionally, you may provide which parts of the zettel you are requesting.
In this case, add an additional query parameter ''part=PART''.

id: 00001012053400
title: API: Retrieve metadata of an existing zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20210726174524
modified: 20230807170155

The [[endpoint|00001012920000]] to work with metadata of a specific zettel is ''/z/{ID}'', where ''{ID}'' is a placeholder for the [[zettel identifier|00001006050000]][^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header].

To retrieve the plain metadata of a zettel, use the query parameter ''part=meta''

````sh
# curl 'http://127.0.0.1:23123/z/00001012053400?part=meta'
title: API: Retrieve metadata of an existing zettel
role: manual

id: 00001012053500
title: API: Retrieve evaluated metadata and content of an existing zettel in various encodings
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20210726174524
modified: 20240620171057

The [[endpoint|00001012920000]] to work with evaluated metadata and content of a specific zettel is ''/z/{ID}'', where ''{ID}'' is a placeholder for the [[zettel identifier|00001006050000]].

For example, to retrieve some evaluated data about this zettel you are currently viewing in [[Sz encoding|00001012920516]], just send a HTTP GET request to the endpoint ''/z/00001012053500''[^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header] with the query parameter ''enc=sz''.
If successful, the output is a symbolic expression value:
```sh
# curl 'http://127.0.0.1:23123/z/00001012053500?enc=sz'
(BLOCK (PARA (TEXT "The ") (LINK-ZETTEL () "00001012920000" (TEXT "endpoint")) (TEXT " to work with parsed metadata and content of a specific zettel is ") (LITERAL-INPUT () "/z/{ID}") (TEXT ", where ") (LITERAL-INPUT () "{ID}") (TEXT " is a placeholder for the ") ...
```

To select another encoding, you must provide the query parameter ''enc=ENCODING''.

id: 00001012053600
title: API: Retrieve parsed metadata and content of an existing zettel in various encodings
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240620170909

The [[endpoint|00001012920000]] to work with parsed metadata and content of a specific zettel is ''/z/{ID}'', where ''{ID}'' is a placeholder for the [[zettel identifier|00001006050000]].

A __parsed__ zettel is basically an [[unevaluated|00001012053500]] zettel: the zettel is read and analyzed, but its content is not __evaluated__.
By using this endpoint, you are able to retrieve the structure of a zettel before it is evaluated.

For example, to retrieve some data about this zettel you are currently viewing, just send a HTTP GET request to the endpoint ''/z/00001012053600''[^If [[authentication is enabled|00001010040100]], you must include the a valid [[access token|00001012050200]] in the ''Authorization'' header] with the query parameter ''parseonly'' (and other appropriate query parameter).
For example:
```sh
# curl 'http://127.0.0.1:23123/z/00001012053600?enc=sz&parseonly'
(BLOCK (PARA (TEXT "The ") (LINK-ZETTEL () "00001012920000" (TEXT "endpoint")) (TEXT " to work with parsed metadata and content of a specific zettel is ") (LITERAL-INPUT () "/z/{ID}") (TEXT ", where ") ...
```

Similar to [[retrieving an encoded zettel|00001012053500]], you can specify an [[encoding|00001012920500]] and state which [[part|00001012920800]] of a zettel you are interested in.

id: 00001012054400
title: API: Rename a zettel
role: manual
tags: #api #manual #zettelstore #deprecated
syntax: zmk
created: 20210713150005
modified: 20240708154151

**Note:** this operation is deprecated and will be removed in version 0.19 (or later).
Do not use it anymore.

If your client application depends on this operation, please get in contact with the [[author/maintainer|00000000000005]] of Zettelstore to find a solution.

---
**Deprecated**

Renaming a zettel is effectively just specifying a new identifier for the zettel.
Since more than one [[box|00001004011200]] might contain a zettel with the old identifier, the rename operation must success in every relevant box to be overall successful.
If the rename operation fails in one box, Zettelstore tries to rollback previous successful operations.

As a consequence, you cannot rename a zettel when its identifier is used in a read-only box.
This applies to all [[predefined zettel|00001005090000]], for example.

The [[endpoint|00001012920000]] to rename a zettel is ''/z/{ID}'', where ''{ID}'' is a placeholder for the [[zettel identifier|00001006050000]].
You must send a HTTP MOVE request to this endpoint, and you must specify the new zettel identifier as an URL, placed under the HTTP request header key ''Destination''.
```
# curl -X MOVE -H "Destination: 10000000000001" http://127.0.0.1:23123/z/00001000000000
```

Only the last 14 characters of the value of ''Destination'' are taken into account and those must form an unused [[zettel identifier|00001006050000]].
If the value contains less than 14 characters that do not form an unused zettel identifier, the response will contain a HTTP status code ''400''.
All other characters, besides those 14 digits, are effectively ignored.
However, the value should form a valid URL that could be used later to [[read the content|00001012053300]] of the freshly renamed zettel.

=== HTTP Status codes
; ''204''
: Rename was successful, there is no body in the response.
; ''400''
: Request was not valid.
  For example, the HTTP header did not contain a valid ''Destination'' key, or the new identifier is already in use.
; ''403''
: You are not allowed to delete the given zettel.
  In most cases you have either not enough [[access rights|00001010070600]] or at least one box containing the given identifier operates in read-only mode.
; ''404''
: Zettel not found.
  You probably used a zettel identifier that is not used in the Zettelstore.

=== Rationale for the MOVE method
HTTP [[standardizes|https://www.rfc-editor.org/rfc/rfc7231.txt]] eight methods.
None of them is conceptually close to a rename operation.

Everyone is free to ""invent"" some new method to be used in HTTP.
To avoid a divergency, there is a [[methods registry|https://www.iana.org/assignments/http-methods/]] that tracks those extensions.
The [[HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)|https://www.rfc-editor.org/rfc/rfc4918.txt]] defines the method MOVE that is quite close to the desired rename operation.
In fact, some command line tools use a ""move"" method for renaming files.

Therefore, Zettelstore adopts somehow WebDAV's MOVE method and its use of the ''Destination'' HTTP header key.

id: 00001012080200
title: API: Check for authentication
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20220103224858
modified: 20220908163156

API clients typically wants to know, whether [[authentication is enabled|00001010040100]] or not.
If authentication is enabled, they present some form of user interface to get user name and password for the actual authentication.
Then they try to [[obtain an access token|00001012050200]].
If authentication is disabled, these steps are not needed.

To check for enabled authentication, you must send a HTTP POST request to the [[endpoint|00001012920000]] ''/x'' and you must specify the query parameter ''cmd=authenticated''.

```sh

id: 00001012080500
title: API: Refresh internal data
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20211230230441
modified: 20220923104836

Zettelstore maintains some internal data to allow faster operations.

One example is the [[content search|00001012051400]] for a term: Zettelstore does not need to scan all zettel to find all occurrences for the term.
Instead, all word are stored internally, with a list of zettel where they occur.

Another example is the way to determine which zettel are stored in a [[ZIP file|00001004011200]].
Scanning a ZIP file is a lengthy operation, therefore Zettelstore maintains a directory of zettel for each ZIP file.

All these internal data may become stale.
This should not happen, but when it comes e.g. to file handling, every operating systems behaves differently in very subtle ways.

id: 00001012920000
title: Endpoints used by the API
role: manual
tags: #api #manual #reference #zettelstore
syntax: zmk
created: 20210126175322
modified: 20240708155042

All API endpoints conform to the pattern ''[PREFIX]LETTER[/ZETTEL-ID]'', where:
; ''PREFIX''
: is the URL prefix (default: ""/""), configured via the ''url-prefix'' [[startup configuration|00001004010000]],
; ''LETTER''
: is a single letter that specifies the resource type,
; ''ZETTEL-ID''
: is an optional 14 digits string that uniquely [[identify a zettel|00001006050000]].

The following letters are currently in use:

|= Letter:| Without zettel identifier | With [[zettel identifier|00001006050000]] | Mnemonic
| ''a'' | POST: [[client authentication|00001012050200]] | | **A**uthenticate
|       | PUT: [[renew access token|00001012050400]] |
| ''x'' | GET: [[retrieve administrative data|00001012070500]] | | E**x**ecute
|       | POST: [[execute command|00001012080100]]
| ''z'' | GET: [[list zettel|00001012051200]]/[[query zettel|00001012051400]] | GET: [[retrieve zettel|00001012053300]] | **Z**ettel
|       | POST: [[create new zettel|00001012053200]] | PUT: [[update zettel|00001012054200]]
|       |  | DELETE: [[delete zettel|00001012054600]]
|       |  | MOVE: [[rename zettel|00001012054400]][^Renaming a zettel is deprecated and will be removed in version 0.19 or later.]

The full URL will contain either the ""http"" oder ""https"" scheme, a host name, and an optional port number.

The API examples will assume the ""http"" schema, the local host ""127.0.0.1"", the default port ""23123"", and the default empty ''PREFIX'' ""/"".
Therefore, all URLs in the API documentation will begin with ""http://127.0.0.1:23123/"".

id: 00001012921200
title: API: Encoding of Zettel Access Rights
role: manual
tags: #api #manual #reference #zettelstore
syntax: zmk
created: 20220201173115
modified: 20240708155122

Various API calls return a symbolic expression list ''(rights N)'', with ''N'' as a number, that encodes the access rights the user currently has.
''N'' is an integer number between 0 and 62.[^Not all values in this range are used.]

The value ""0"" signals that something went wrong internally while determining the access rights.

A value of ""1"" says, that the current user has no access right for the given zettel.
In most cases, this value will not occur, because only zettel are presented, which are at least readable by the current user.

Values ""2"" to ""62"" are binary encoded values, where each bit signals a special right.

|=Bit number:|Bit value:|Meaning
| 1 |  2 | User is allowed to create a new zettel
| 2 |  4 | User is allowed to read the zettel
| 3 |  8 | User is allowed to update the zettel
| 4 | 16 | User is allowed to rename the zettel[^Renaming a zettel is deprecated and will be removed in version 0.19 or later.]
| 5 | 32 | User is allowed to delete the zettel

The algorithm to calculate the actual access rights from the value is relatively simple:
# Search for the biggest bit value that is less than the rights value.
  This is an access right for the current user.
# Subtract the bit value from the rights value.
  Remember the difference as the new rights value.

id: 00001012931400
title: Encoding of Sz Block Elements
role: manual
tags: #api #manual #reference #zettelstore
syntax: zmk
created: 20230403161803
modified: 20240123120132

=== ''PARA''
:::syntax
__Paragraph__ **=** ''(PARA'' [[__InlineElement__|00001012931600]] … '')''.
:::
A paragraph is just a list of inline elements.

:::
A list element is either a block or an inline.
If it is a block, it may contain a nested list.
=== ''DESCRIPTION''
:::syntax
__Description__ **=** ''(DESCRIPTION'' __DescriptionTerm__ __DescriptionValues__ __DescriptionTerm__ __DescriptionValues__ … '')''.
:::
A description is a sequence of one ore more terms and values.

:::syntax
__DescriptionTerm__ **=** ''('' [[__InlineElement__|00001012931600]] … '')''.
:::
A description term is just an inline-structured value.

:::syntax

Attributes may further specify the quotation.
The inline typically describes author / source of the quotation.

:::syntax
__VerseRegion__ **=** ''(REGION-VERSE'' [[__Attributes__|00001012931000#attribute]] ''('' [[__BlockElement__|00001012931400]] … '')'' [[__InlineElement__|00001012931600]] … '')''.
:::
A block region just treats the block to contain a verse.
Soft line break are transformed into hard line breaks to save the structure of the verse / poem.
Attributes may further specify something.
The inline typically describes author / source of the verse.

=== ''VERBATIM-*''
The following lists specifies some literal text of more than one line.
The structure is always the same, the initial symbol denotes the actual usage.
The content is encoded as a string, most likely to contain control characters that signals the end of a line.

id: 00001012931600
title: Encoding of Sz Inline Elements
role: manual
tags: #api #manual #reference #zettelstore
syntax: zmk
created: 20230403161845
modified: 20240620170546

=== ''TEXT''
:::syntax
__Text__ **=** ''(TEXT'' String '')''.
:::
Specifies the string as some text content, including white space characters.

=== ''EMBED-BLOB''
:::syntax
__EmbedBLOB__ **=** ''(EMBED-BLOB'' [[__Attributes__|00001012931000#attribute]] String,,1,, String,,2,, '')''.
:::
If used if some processed image has to be embedded inside some inline material.
The first string specifies the syntax of the image content.
The second string contains the image content.
If the syntax is ""SVG"", the image content is not further encoded.
Otherwise a base64 encoding is used.

=== ''CITE''
:::syntax
__CiteBLOB__ **=** ''(CITE'' [[__Attributes__|00001012931000#attribute]] String [[__InlineElement__|00001012931600]] … '')''.
:::
The string contains the citation key.

__InsertFormat__ **=** ''(FORMAT-INSERT'' [[__Attributes__|00001012931000#attribute]] [[__InlineElement__|00001012931600]] … '')''.
:::
The inline text should be treated as inserted.

:::syntax
__MarkFormat__ **=** ''(FORMAT-MARK'' [[__Attributes__|00001012931000#attribute]] [[__InlineElement__|00001012931600]] … '')''.
:::
The inline text should be treated as highlighted for the reader (but was not important fto the original author).

:::syntax
__QuoteFormat__ **=** ''(FORMAT-QUOTE'' [[__Attributes__|00001012931000#attribute]] [[__InlineElement__|00001012931600]] … '')''.
:::
The inline text should be treated as quoted text.

:::syntax

id: 00001017000000
title: Tips and Tricks
role: manual
tags: #manual #zettelstore
syntax: zmk
created: 20220803170112
modified: 20231012154803

=== Welcome Zettel
* **Problem:** You want to put your Zettelstore into the public and need a starting zettel for your users.
  In addition, you still want a ""home zettel"", with all your references to internal, non-public zettel.
  Zettelstore only allows to specify one [[''home-zettel''|00001004020000#home-zettel]].
* **Solution 1:**
*# Create a new zettel with all your references to internal, non-public zettel.

* **Solution 2:** If you typically start your Zettelstore on the command line, you could use the ''-d DIR'' option for the [[''run''|00001004051000#d]] sub-command.
  In this case you are allowed to use the character ""''~''"".

  ''zettelstore run -d ~/Library/Mobile\\ Documents/com\\~apple\\~CloudDocs/zettel''

  (The ""''\\''"" is needed by the command line processor to mask the following character to be processed in unintended ways.)
* **Discussion:** Zettel files are synchronized between your computers via iCloud.
  Is does not matter, if one of your computer is offline / switched off.
  iCloud will synchronize the zettel files if it later comes online.

  However, if you use more than one computer simultaneously, you must be aware that synchronization takes some time.
  It might take several seconds, maybe longer, that new new version of a zettel appears on the other computer.
  If you update the same zettel on multiple computers at nearly the same time, iCloud will not be able to synchronize the different versions in a safe manner.
  Zettelstore is intentionally not aware of any synchronization within its zettel boxes.

  If Zettelstore behaves strangely after a synchronization took place, the page about [[Troubleshooting|00001018000000#working-with-files]] might contain some useful information.

id: 00001018000000
title: Troubleshooting
role: manual
tags: #manual #zettelstore
syntax: zmk
created: 20211027105921
modified: 20240221134749

This page lists some problems and their solutions that may occur when using your Zettelstore.

=== Installation
* **Problem:** When you double-click on the Zettelstore executable icon, macOS complains that Zettelstore is an application from an unknown developer.
  Therefore, it will not start Zettelstore.
** **Solution:** Press the ''Ctrl'' key while opening the context menu of the Zettelstore executable with a right-click.
   A dialog is then opened where you can acknowledge that you understand the possible risks when you start Zettelstore.
   This dialog is only resented once for a given Zettelstore executable.
* **Problem:** When you double-click on the Zettelstore executable icon, Windows complains that Zettelstore is an application from an unknown developer.
** **Solution:** Windows displays a dialog where you can acknowledge possible risks and allows to start Zettelstore.

=== Authentication
* **Problem:** [[Authentication is enabled|00001010040100]] for a local running Zettelstore and there is a valid [[user zettel|00001010040200]] for the owner.
  But entering user name and password at the [[web user interface|00001014000000]] seems to be ignored, while entering a wrong password will result in an error message.
** **Explanation:** A local running Zettelstore typically means, that you are accessing the Zettelstore using an URL with schema ''http://'', and not ''https://'', for example ''http://localhost:23123''.
   The difference between these two is the missing encryption of user name / password and for the answer of the Zettelstore if you use the ''http://'' schema.
   To be secure by default, the Zettelstore will not work in an insecure environment.

** **Solution 3:** If you have an enabled [[Administrator Console|00001004100000]] you can use the command [[''refresh''|00001004101000#refresh]] to make your changes visible.
** **Solution 4:** You configure the zettel box as [[""simple""|00001004011400]].

=== HTML content is not shown
* **Problem:** You have entered some HTML code as content for your Zettelstore, but this content is not shown on the Web User Interface.

  You may have entered a Zettel with syntax [[""html""|00001008000000#html]], or you have used an [[inline-zettel block|00001007031200]] with syntax ""html"", or you entered a Zettel with syntax [[""markdown""|00001008000000#markdown]] (or ""md"") and used some HTML code fragments.
** **Explanation:** Working with HTML code from unknown sources may lead so severe security problems.
   The HTML code may force web browsers to load more content from external server, it may contain malicious JavaScript code, it may reference to CSS artifacts that itself load from external servers and may contains malicious software.
   Zettelstore tries to do its best to ignore problematic HTML code, but it may fail.
   Either because of unknown bugs or because of yet unknown changes in the future.

   Zettelstore sets a restrictive [[Content Security Policy|https://www.w3.org/TR/CSP/]], but this depends on web browsers to implement them correctly and on users to not disable it.
   Zettelstore will not display any HTML code, which contains a ``<script>>`` or an ``<iframe>`` tag.
   But attackers may find other ways to deploy their malicious code.

   Therefore, Zettelstore disallows any HTML content as a default.
   If you know what you are doing, e.g. because you will never copy HTML code you do not understand, you can relax this default.
** **Solution 1:** If you want zettel with syntax ""html"" not to be ignored, you set the startup configuration key [[''insecure-html''|00001004010000#insecure-html]] to the value ""html"".
** **Solution 2:** If you want zettel with syntax ""html"" not to be ignored, **and** want to allow HTML in Markdown, you set the startup configuration key [[''insecure-html''|00001004010000#insecure-html]] to the value ""markdown"".
** **Solution 3:** If you want zettel with syntax ""html"" not to be ignored, **and** want to allow HTML in Markdown, **and** want to use HTML code within Zettelmarkup, you set the startup configuration key [[''insecure-html''|00001004010000#insecure-html]] to the value ""zettelmarkup"".

		},
	},
	{
		descr: "Quote Block with multiple paragraphs",
		zmk:   "<<<\nToBeOr\n\nNotToBe\n<<< Romeo",
		expect: expectMap{
			encoderHTML:  "<blockquote><p>ToBeOr</p><p>NotToBe</p><cite>Romeo</cite></blockquote>",
			encoderMD:    "> ToBeOr\n\n> NotToBe",
			encoderSz:    `(BLOCK (REGION-QUOTE () ((PARA (TEXT "ToBeOr")) (PARA (TEXT "NotToBe"))) (TEXT "Romeo")))`,
			encoderSHTML: `((blockquote (p "ToBeOr") (p "NotToBe") (cite "Romeo")))`,
			encoderText:  "ToBeOr\nNotToBe\nRomeo",
			encoderZmk:   useZmk,
		},
	},
	{

	{
		descr: "Table with alignment and comment",
		zmk: `|h1>|=h2|h3:|
|%--+---+---+
|<c1|c2|:c3|
|f1|f2|=f3`,
		expect: expectMap{
			encoderHTML:  `<table><thead><tr><td class="right">h1</td><td>h2</td><td class="center">h3</td></tr></thead><tbody><tr><td class="left">c1</td><td>c2</td><td class="center">c3</td></tr><tr><td class="right">f1</td><td>f2</td><td class="center">=f3</td></tr></tbody></table>`,
			encoderMD:    "",
			encoderSz:    `(BLOCK (TABLE ((CELL-RIGHT (TEXT "h1")) (CELL (TEXT "h2")) (CELL-CENTER (TEXT "h3"))) ((CELL-LEFT (TEXT "c1")) (CELL (TEXT "c2")) (CELL-CENTER (TEXT "c3"))) ((CELL-RIGHT (TEXT "f1")) (CELL (TEXT "f2")) (CELL-CENTER (TEXT "=f3")))))`,
			encoderSHTML: `((table (thead (tr (td (@ (class . "right")) "h1") (td "h2") (td (@ (class . "center")) "h3"))) (tbody (tr (td (@ (class . "left")) "c1") (td "c2") (td (@ (class . "center")) "c3")) (tr (td (@ (class . "right")) "f1") (td "f2") (td (@ (class . "center")) "=f3")))))`,
			encoderText:  "h1 h2 h3\nc1 c2 c3\nf1 f2 =f3",
			encoderZmk: `|=h1>|=h2|=h3:
|<c1|c2|c3
|f1|f2|=f3`,
		},
	},
	{

		},
	},
	{
		descr: "Quotes formatting",
		zmk:   `""quotes""`,
		expect: expectMap{
			encoderHTML:  "“quotes”",
			encoderMD:    "<q>quotes</q>",
			encoderSz:    `(INLINE (FORMAT-QUOTE () (TEXT "quotes")))`,
			encoderSHTML: `((@L (@H "&ldquo;") "quotes" (@H "&rdquo;")))`,
			encoderText:  `quotes`,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Quotes formatting (german)",
		zmk:   `""quotes""{lang=de}`,
		expect: expectMap{
			encoderHTML:  `<span lang="de">&bdquo;quotes&ldquo;</span>`,
			encoderMD:    "<q>quotes</q>",
			encoderSz:    `(INLINE (FORMAT-QUOTE (("lang" . "de")) (TEXT "quotes")))`,
			encoderSHTML: `((span (@ (lang . "de")) (@H "&bdquo;") "quotes" (@H "&ldquo;")))`,
			encoderText:  `quotes`,
			encoderZmk:   `""quotes""{lang="de"}`,
		},
	},
	{
		descr: "Empty quotes (default)",
		zmk:   `""""`,
		expect: expectMap{
			encoderHTML:  `&ldquo;&rdquo;`,
			encoderMD:    "<q></q>",
			encoderSz:    `(INLINE (FORMAT-QUOTE ()))`,
			encoderSHTML: `((@L (@H "&ldquo;" "&rdquo;")))`,
			encoderText:  ``,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Empty quotes (unknown)",
		zmk:   `""""{lang=unknown}`,
		expect: expectMap{
			encoderHTML:  `<span lang="unknown">&quot;&quot;</span>`,
			encoderMD:    "<q></q>",
			encoderSz:    `(INLINE (FORMAT-QUOTE (("lang" . "unknown"))))`,
			encoderSHTML: `((span (@ (lang . "unknown")) (@H "&quot;" "&quot;")))`,
			encoderText:  ``,
			encoderZmk:   `""""{lang="unknown"}`,
		},
	},
	{
		descr: "Nested quotes (default)",
		zmk:   `""say: ::""yes, ::""or?""::""::""`,
		expect: expectMap{
			encoderHTML:  `&ldquo;say: <span>&lsquo;yes, <span>&ldquo;or?&rdquo;</span>&rsquo;</span>&rdquo;`,
			encoderMD:    "<q>say: <q>yes, <q>or?</q></q></q>",
			encoderSz:    `(INLINE (FORMAT-QUOTE () (TEXT "say: ") (FORMAT-SPAN () (FORMAT-QUOTE () (TEXT "yes, ") (FORMAT-SPAN () (FORMAT-QUOTE () (TEXT "or?")))))))`,
			encoderSHTML: `((@L (@H "&ldquo;") "say: " (span (@L (@H "&lsquo;") "yes, " (span (@L (@H "&ldquo;") "or?" (@H "&rdquo;"))) (@H "&rsquo;"))) (@H "&rdquo;")))`,
			encoderText:  `say: yes, or?`,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Two quotes",
		zmk:   `""yes"" or ""no""`,
		expect: expectMap{
			encoderHTML:  `&ldquo;yes&rdquo; or &ldquo;no&rdquo;`,
			encoderMD:    "<q>yes</q> or <q>no</q>",
			encoderSz:    `(INLINE (FORMAT-QUOTE () (TEXT "yes")) (TEXT " or ") (FORMAT-QUOTE () (TEXT "no")))`,
			encoderSHTML: `((@L (@H "&ldquo;") "yes" (@H "&rdquo;")) " or " (@L (@H "&ldquo;") "no" (@H "&rdquo;")))`,
			encoderText:  `yes or no`,
			encoderZmk:   useZmk,
		},
	},
	{

		},
	},
	{
		descr: "Input formatting",
		zmk:   `''input''`,
		expect: expectMap{
			encoderHTML:  `<kbd>input</kbd>`,
			encoderMD:    "input",
			encoderSz:    `(INLINE (LITERAL-INPUT () "input"))`,
			encoderSHTML: `((kbd "input"))`,
			encoderText:  `input`,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Output formatting",
		zmk:   `==output==`,
		expect: expectMap{
			encoderHTML:  `<samp>output</samp>`,
			encoderMD:    "output",
			encoderSz:    `(INLINE (LITERAL-OUTPUT () "output"))`,
			encoderSHTML: `((samp "output"))`,
			encoderText:  `output`,
			encoderZmk:   useZmk,
		},
	},
	{

		},
	},
	{
		descr: "Nested Span Quote formatting",
		zmk:   `::""abc""::{lang=fr}`,
		expect: expectMap{
			encoderHTML:  `<span lang="fr">&laquo;&nbsp;abc&nbsp;&raquo;</span>`,
			encoderMD:    "<q>abc</q>",
			encoderSz:    `(INLINE (FORMAT-SPAN (("lang" . "fr")) (FORMAT-QUOTE () (TEXT "abc"))))`,
			encoderSHTML: `((span (@ (lang . "fr")) (@L (@H "&laquo;" "&nbsp;") "abc" (@H "&nbsp;" "&raquo;"))))`,
			encoderText:  `abc`,
			encoderZmk:   `::""abc""::{lang="fr"}`,
		},
	},
	{

			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Dummy Link",
		zmk:   `[[abc]]`,
		expect: expectMap{
			encoderHTML:  `<a class="external" href="abc">abc</a>`,
			encoderMD:    "[abc](abc)",
			encoderSz:    `(INLINE (LINK-EXTERNAL () "abc"))`,
			encoderSHTML: `((a (@ (class . "external") (href . "abc")) "abc"))`,
			encoderText:  ``,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Simple URL",
		zmk:   `[[https://zettelstore.de]]`,
		expect: expectMap{
			encoderHTML:  `<a class="external" href="https://zettelstore.de">https://zettelstore.de</a>`,
			encoderMD:    "<https://zettelstore.de>",
			encoderSz:    `(INLINE (LINK-EXTERNAL () "https://zettelstore.de"))`,
			encoderSHTML: `((a (@ (class . "external") (href . "https://zettelstore.de")) "https://zettelstore.de"))`,
			encoderText:  ``,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "URL with Text",
		zmk:   `[[Home|https://zettelstore.de]]`,
		expect: expectMap{
			encoderHTML:  `<a class="external" href="https://zettelstore.de">Home</a>`,
			encoderMD:    "[Home](https://zettelstore.de)",
			encoderSz:    `(INLINE (LINK-EXTERNAL () "https://zettelstore.de" (TEXT "Home")))`,
			encoderSHTML: `((a (@ (class . "external") (href . "https://zettelstore.de")) "Home"))`,
			encoderText:  `Home`,
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Simple Zettel ID",
		zmk:   `[[00000000000100]]`,

	"zettelstore.de/z/encoder/szenc"
	"zettelstore.de/z/encoder/textenc"
	"zettelstore.de/z/parser"
	"zettelstore.de/z/zettel/meta"
)

func init() {


	encoder.Register(api.EncoderHTML, func(params *encoder.CreateParameter) encoder.Encoder { return Create(params) })

}

// Create an encoder.
func Create(params *encoder.CreateParameter) *Encoder {
	// We need a new transformer every time, because tx.inVerse must be unique.
	// If we can refactor it out, the transformer can be created only once.
	return &Encoder{
		tx:      szenc.NewTransformer(),
		th:      shtml.NewEvaluator(1),
		lang:    params.Lang,
		textEnc: textenc.Create(),
	}
}


type Encoder struct {
	tx      *szenc.Transformer
	th      *shtml.Evaluator
	lang    string
	textEnc *textenc.Encoder
}

	}

	xast := he.tx.GetSz(&zn.Ast)
	hast, err := he.th.Evaluate(xast, &env)
	if err != nil {
		return 0, err
	}
	hen := he.th.Endnotes(&env)

	var head sx.ListBuilder
	head.Add(shtml.SymHead)
	head.Add(sx.Nil().Cons(sx.Nil().Cons(sx.Cons(sx.MakeSymbol("charset"), sx.MakeString("utf-8"))).Cons(sxhtml.SymAttr)).Cons(shtml.SymMeta))
	head.ExtendBang(hm)
	var sb strings.Builder
	if hasTitle {

	if hen != nil {
		body.Add(sx.Cons(shtml.SymHR, nil))
		body.Add(hen)
	}

	doc := sx.MakeList(
		sxhtml.SymDoctype,
		sx.MakeList(shtml.SymHtml, head.List(), body.List()),
	)

	gen := sxhtml.NewGenerator().SetNewline()
	return gen.WriteHTML(w, doc)
}

// WriteMeta encodes meta data as HTML5.
func (he *Encoder) WriteMeta(w io.Writer, m *meta.Meta, evalMeta encoder.EvalMetaFunc) (int, error) {
	env := shtml.MakeEnvironment(he.lang)
	hm, err := he.th.Evaluate(he.tx.GetMeta(m, evalMeta), &env)
	if err != nil {
		return 0, err
	}
	gen := sxhtml.NewGenerator().SetNewline()
	return gen.WriteListHTML(w, hm)
}


func (he *Encoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return he.WriteBlocks(w, &zn.Ast)
}

// WriteBlocks encodes a block slice.
func (he *Encoder) WriteBlocks(w io.Writer, bs *ast.BlockSlice) (int, error) {
	env := shtml.MakeEnvironment(he.lang)
	hobj, err := he.th.Evaluate(he.tx.GetSz(bs), &env)
	if err == nil {
		gen := sxhtml.NewGenerator()
		length, err2 := gen.WriteListHTML(w, hobj)
		if err2 != nil {
			return length, err2
		}

		l, err2 := gen.WriteHTML(w, he.th.Endnotes(&env))
		length += l
		return length, err2
	}
	return 0, err
}

// WriteInlines writes an inline slice to the writer

// Package mdenc encodes the abstract syntax tree back into Markdown.
package mdenc

import (
	"io"

	"t73f.de/r/zsc/api"


	"zettelstore.de/z/ast"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/zettel/meta"
)

func init() {


	encoder.Register(api.EncoderMD, func(*encoder.CreateParameter) encoder.Encoder { return Create() })

}

// Create an encoder.
func Create() *Encoder { return &myME }




type Encoder struct{}


var myME Encoder

// WriteZettel writes the encoded zettel to the writer.
func (*Encoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, evalMeta encoder.EvalMetaFunc) (int, error) {
	v := newVisitor(w)
	v.acceptMeta(zn.InhMeta, evalMeta)
	if zn.InhMeta.YamlSep {
		v.b.WriteString("---\n")
	} else {
		v.b.WriteByte('\n')
	}
	ast.Walk(v, &zn.Ast)
	length, err := v.b.Flush()
	return length, err
}

// WriteMeta encodes meta data as markdown.
func (*Encoder) WriteMeta(w io.Writer, m *meta.Meta, evalMeta encoder.EvalMetaFunc) (int, error) {
	v := newVisitor(w)
	v.acceptMeta(m, evalMeta)
	length, err := v.b.Flush()
	return length, err
}

func (v *visitor) acceptMeta(m *meta.Meta, evalMeta encoder.EvalMetaFunc) {
	for _, p := range m.ComputedPairs() {
		key := p.Key
		v.b.WriteStrings(key, ": ")
		if meta.Type(key) == meta.TypeZettelmarkup {
			is := evalMeta(p.Value)
			ast.Walk(v, &is)
		} else {
			v.b.WriteString(p.Value)
		}
		v.b.WriteByte('\n')
	}
}


func (ze *Encoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return ze.WriteBlocks(w, &zn.Ast)
}

// WriteBlocks writes the content of a block slice to the writer.
func (*Encoder) WriteBlocks(w io.Writer, bs *ast.BlockSlice) (int, error) {
	v := newVisitor(w)
	ast.Walk(v, bs)
	length, err := v.b.Flush()
	return length, err
}

// WriteInlines writes an inline slice to the writer
func (*Encoder) WriteInlines(w io.Writer, is *ast.InlineSlice) (int, error) {
	v := newVisitor(w)
	ast.Walk(v, is)
	length, err := v.b.Flush()
	return length, err
}

// visitor writes the abstract syntax tree to an EncWriter.
type visitor struct {
	b          encoder.EncWriter
	listInfo   []int
	listPrefix string


}

func newVisitor(w io.Writer) *visitor {
	return &visitor{b: encoder.NewEncWriter(w)}





















}

func (v *visitor) Visit(node ast.Node) ast.Visitor {
	switch n := node.(type) {
	case *ast.BlockSlice:
		v.visitBlockSlice(n)
	case *ast.VerbatimNode:

	}
}

func (v *visitor) visitRegion(rn *ast.RegionNode) {
	if rn.Kind != ast.RegionQuote {
		return
	}



	first := true
	for _, bn := range rn.Blocks {
		pn, ok := bn.(*ast.ParaNode)
		if !ok {
			continue
		}
		if !first {
			v.b.WriteString("\n\n")
		}
		first = false
		v.b.WriteString("> ")
		ast.Walk(v, &pn.Inlines)
	}
}

func (v *visitor) visitHeading(hn *ast.HeadingNode) {



	const headingSigns = "###### "
	v.b.WriteString(headingSigns[len(headingSigns)-hn.Level-1:])
	ast.Walk(v, &hn.Inlines)
}

func (v *visitor) visitNestedList(ln *ast.NestedListNode) {
	switch ln.Kind {

			v.writeSpaces(4*l - 4)
			v.b.WriteString(v.listPrefix)
		}
	}
}

func (v *visitor) visitLink(ln *ast.LinkNode) {



	v.writeReference(ln.Ref, ln.Inlines)
}

func (v *visitor) visitEmbedRef(en *ast.EmbedRefNode) {



	v.b.WriteByte('!')
	v.writeReference(en.Ref, en.Inlines)
}

func (v *visitor) writeReference(ref *ast.Reference, is ast.InlineSlice) {
	if ref.State == ast.RefStateQuery {
		ast.Walk(v, &is)

	if ref.State != ast.RefStateExternal || ref.URL == nil {
		return false
	}
	return ref.URL.Scheme != ""
}

func (v *visitor) visitFormat(fn *ast.FormatNode) {



	switch fn.Kind {
	case ast.FormatEmph:
		v.b.WriteByte('*')
		ast.Walk(v, &fn.Inlines)
		v.b.WriteByte('*')
	case ast.FormatStrong:
		v.b.WriteString("__")
		ast.Walk(v, &fn.Inlines)
		v.b.WriteString("__")
	case ast.FormatQuote:
		v.b.WriteString("<q>")
		ast.Walk(v, &fn.Inlines)
		v.b.WriteString("</q>")
	case ast.FormatMark:
		v.b.WriteString("<mark>")
		ast.Walk(v, &fn.Inlines)
		v.b.WriteString("</mark>")
	default:
		ast.Walk(v, &fn.Inlines)
	}
}
















func (v *visitor) visitLiteral(ln *ast.LiteralNode) {
	switch ln.Kind {
	case ast.LiteralProg:
		v.b.WriteByte('`')
		v.b.Write(ln.Content)
		v.b.WriteByte('`')
	case ast.LiteralComment, ast.LiteralHTML: // ignore everything
	default:
		v.b.Write(ln.Content)
	}

	return &Encoder{
		tx:   szenc.NewTransformer(),
		th:   shtml.NewEvaluator(1),
		lang: params.Lang,
	}
}


type Encoder struct {
	tx   *szenc.Transformer
	th   *shtml.Evaluator
	lang string
}

// WriteZettel writes the encoded zettel to the writer.

	metaSHTML, err := enc.th.Evaluate(enc.tx.GetMeta(m, evalMeta), &env)
	if err != nil {
		return 0, err
	}
	return sx.Print(w, metaSHTML)
}


func (enc *Encoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return enc.WriteBlocks(w, &zn.Ast)
}

// WriteBlocks writes a block slice to the writer
func (enc *Encoder) WriteBlocks(w io.Writer, bs *ast.BlockSlice) (int, error) {
	env := shtml.MakeEnvironment(enc.lang)

// Create a S-expr encoder
func Create() *Encoder {
	// We need a new transformer every time, because trans.inVerse must be unique.
	// If we can refactor it out, the transformer can be created only once.
	return &Encoder{trans: NewTransformer()}
}


type Encoder struct {
	trans *Transformer
}

// WriteZettel writes the encoded zettel to the writer.
func (enc *Encoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, evalMeta encoder.EvalMetaFunc) (int, error) {
	content := enc.trans.GetSz(&zn.Ast)
	meta := enc.trans.GetMeta(zn.InhMeta, evalMeta)
	return sx.MakeList(meta, content).Print(w)
}

// WriteMeta encodes meta data as s-expression.
func (enc *Encoder) WriteMeta(w io.Writer, m *meta.Meta, evalMeta encoder.EvalMetaFunc) (int, error) {
	return enc.trans.GetMeta(m, evalMeta).Print(w)
}


func (enc *Encoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return enc.WriteBlocks(w, &zn.Ast)
}

// WriteBlocks writes a block slice to the writer
func (enc *Encoder) WriteBlocks(w io.Writer, bs *ast.BlockSlice) (int, error) {
	return enc.trans.GetSz(bs).Print(w)
}

// WriteInlines writes an inline slice to the writer
func (enc *Encoder) WriteInlines(w io.Writer, is *ast.InlineSlice) (int, error) {
	return enc.trans.GetSz(is).Print(w)
}

// NewTransformer returns a new transformer to create s-expressions from AST nodes.
func NewTransformer() *Transformer {
	t := Transformer{}
	return &t
}


type Transformer struct {
	inVerse bool
}


func (t *Transformer) GetSz(node ast.Node) *sx.Pair {
	switch n := node.(type) {
	case *ast.BlockSlice:
		return t.getBlockList(n).Cons(sz.SymBlock)
	case *ast.InlineSlice:
		return t.getInlineList(*n).Cons(sz.SymInline)
	case *ast.ParaNode:

	meta.TypeTagSet:       sz.SymTypeTagSet,
	meta.TypeTimestamp:    sz.SymTypeTimestamp,
	meta.TypeURL:          sz.SymTypeURL,
	meta.TypeWord:         sz.SymTypeWord,
	meta.TypeZettelmarkup: sz.SymTypeZettelmarkup,
}


func (t *Transformer) GetMeta(m *meta.Meta, evalMeta encoder.EvalMetaFunc) *sx.Pair {
	pairs := m.ComputedPairs()
	objs := make(sx.Vector, 0, len(pairs))
	for _, p := range pairs {
		key := p.Key
		ty := m.Type(key)
		symType := mapGetS(mapMetaTypeS, ty)

func init() {
	encoder.Register(api.EncoderText, func(*encoder.CreateParameter) encoder.Encoder { return Create() })
}

// Create an encoder.
func Create() *Encoder { return &myTE }


type Encoder struct{}

var myTE Encoder // Only a singleton is required.

// WriteZettel writes metadata and content.
func (te *Encoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, evalMeta encoder.EvalMetaFunc) (int, error) {
	v := newVisitor(w)

			buf.WriteByte(' ')
		}
		buf.WriteString(meta.CleanTag(tag))
	}

}


func (te *Encoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return te.WriteBlocks(w, &zn.Ast)
}

// WriteBlocks writes the content of a block slice to the writer.
func (*Encoder) WriteBlocks(w io.Writer, bs *ast.BlockSlice) (int, error) {
	v := newVisitor(w)

func init() {
	encoder.Register(api.EncoderZmk, func(*encoder.CreateParameter) encoder.Encoder { return Create() })
}

// Create an encoder.
func Create() *Encoder { return &myZE }


type Encoder struct{}

var myZE Encoder

// WriteZettel writes the encoded zettel to the writer.
func (*Encoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, evalMeta encoder.EvalMetaFunc) (int, error) {
	v := newVisitor(w)

		} else {
			v.b.WriteString(p.Value)
		}
		v.b.WriteByte('\n')
	}
}


func (ze *Encoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return ze.WriteBlocks(w, &zn.Ast)
}

// WriteBlocks writes the content of a block slice to the writer.
func (*Encoder) WriteBlocks(w io.Writer, bs *ast.BlockSlice) (int, error) {
	v := newVisitor(w)

//-----------------------------------------------------------------------------
// Copyright (c) 2022-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2022-present Detlef Stern
//-----------------------------------------------------------------------------

// Package atom provides an Atom encoding.
package atom

import (
	"bytes"
	"time"

	"t73f.de/r/zsc/api"
	"zettelstore.de/z/config"
	"zettelstore.de/z/encoding"
	"zettelstore.de/z/encoding/xml"
	"zettelstore.de/z/kernel"
	"zettelstore.de/z/query"
	"zettelstore.de/z/strfun"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

const ContentType = "application/atom+xml"

type Configuration struct {
	Title            string
	Generator        string
	NewURLBuilderAbs func() *api.URLBuilder
}

func (c *Configuration) Setup(cfg config.Config) {
	baseURL := kernel.Main.GetConfig(kernel.WebService, kernel.WebBaseURL).(string)

	c.Title = cfg.GetSiteName()
	c.Generator = (kernel.Main.GetConfig(kernel.CoreService, kernel.CoreProgname).(string) +
		" " +
		kernel.Main.GetConfig(kernel.CoreService, kernel.CoreVersion).(string))
	c.NewURLBuilderAbs = func() *api.URLBuilder { return api.NewURLBuilder(baseURL, 'h') }
}

func (c *Configuration) Marshal(q *query.Query, ml []*meta.Meta) []byte {
	atomUpdated := encoding.LastUpdated(ml, time.RFC3339)
	feedLink := c.NewURLBuilderAbs().String()

	var buf bytes.Buffer
	buf.WriteString(`<feed xmlns="http://www.w3.org/2005/Atom">` + "\n")
	xml.WriteTag(&buf, "  ", "title", c.Title)
	xml.WriteTag(&buf, "  ", "id", feedLink)
	buf.WriteString(`  <link rel="self" href="`)
	if s := q.String(); s != "" {
		strfun.XMLEscape(&buf, c.NewURLBuilderAbs().AppendQuery(s).String())
	} else {
		strfun.XMLEscape(&buf, feedLink)
	}
	buf.WriteString(`"/>` + "\n")
	if atomUpdated != "" {
		xml.WriteTag(&buf, "  ", "updated", atomUpdated)
	}
	xml.WriteTag(&buf, "  ", "generator", c.Generator)
	buf.WriteString("  <author><name>Unknown</name></author>\n")

	for _, m := range ml {
		c.marshalMeta(&buf, m)
	}

	buf.WriteString("</feed>")
	return buf.Bytes()
}

func (c *Configuration) marshalMeta(buf *bytes.Buffer, m *meta.Meta) {
	entryUpdated := ""
	if val, found := m.Get(api.KeyPublished); found {
		if published, err := time.ParseInLocation(id.TimestampLayout, val, time.Local); err == nil {
			entryUpdated = published.UTC().Format(time.RFC3339)
		}
	}

	link := c.NewURLBuilderAbs().SetZid(m.Zid.ZettelID()).String()

	buf.WriteString("  <entry>\n")
	xml.WriteTag(buf, "    ", "title", encoding.TitleAsText(m))
	xml.WriteTag(buf, "    ", "id", link)
	buf.WriteString(`    <link rel="self" href="`)
	strfun.XMLEscape(buf, link)
	buf.WriteString(`"/>` + "\n")
	buf.WriteString(`    <link rel="alternate" type="text/html" href="`)
	strfun.XMLEscape(buf, link)
	buf.WriteString(`"/>` + "\n")

	if entryUpdated != "" {
		xml.WriteTag(buf, "    ", "updated", entryUpdated)
	}
	marshalTags(buf, m)
	buf.WriteString("  </entry>\n")
}

func marshalTags(buf *bytes.Buffer, m *meta.Meta) {
	if tags, found := m.GetList(api.KeyTags); found && len(tags) > 0 {
		for _, tag := range tags {
			for len(tag) > 0 && tag[0] == '#' {
				tag = tag[1:]
			}
			if tag != "" {
				buf.WriteString(`    <category term="`)
				strfun.XMLEscape(buf, tag)
				buf.WriteString("\"/>\n")
			}
		}
	}
}

//-----------------------------------------------------------------------------
// Copyright (c) 2022-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2022-present Detlef Stern
//-----------------------------------------------------------------------------

// Package encoding provides helper functions for encodings.
package encoding

import (
	"time"

	"t73f.de/r/zsc/api"
	"zettelstore.de/z/parser"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

// LastUpdated returns the formated time of the zettel which was updated at the latest time.
func LastUpdated(ml []*meta.Meta, timeFormat string) string {
	maxPublished := time.Date(1, time.January, 1, 0, 0, 0, 0, time.Local)
	for _, m := range ml {
		if val, found := m.Get(api.KeyPublished); found {
			if published, err := time.ParseInLocation(id.TimestampLayout, val, time.Local); err == nil {
				if maxPublished.Before(published) {
					maxPublished = published
				}
			}
		}
	}
	if maxPublished.Year() > 1 {
		return maxPublished.UTC().Format(timeFormat)
	}
	return ""
}

// TitleAsText returns the title of a zettel as plain text
func TitleAsText(m *meta.Meta) string { return parser.NormalizedSpacedText(m.GetTitle()) }

//-----------------------------------------------------------------------------
// Copyright (c) 2022-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2022-present Detlef Stern
//-----------------------------------------------------------------------------

// Package rss provides a RSS encoding.
package rss

import (
	"bytes"
	"context"
	"time"

	"t73f.de/r/zsc/api"
	"zettelstore.de/z/config"
	"zettelstore.de/z/encoding"
	"zettelstore.de/z/encoding/xml"
	"zettelstore.de/z/kernel"
	"zettelstore.de/z/query"
	"zettelstore.de/z/strfun"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

const ContentType = "application/rss+xml"

type Configuration struct {
	Title            string
	Language         string
	Copyright        string
	Generator        string
	NewURLBuilderAbs func() *api.URLBuilder
}

func (c *Configuration) Setup(ctx context.Context, cfg config.Config) {
	baseURL := kernel.Main.GetConfig(kernel.WebService, kernel.WebBaseURL).(string)
	defVals := cfg.AddDefaultValues(ctx, &meta.Meta{})

	c.Title = cfg.GetSiteName()
	c.Language = defVals.GetDefault(api.KeyLang, "")
	c.Copyright = defVals.GetDefault(api.KeyCopyright, "")
	c.Generator = (kernel.Main.GetConfig(kernel.CoreService, kernel.CoreProgname).(string) +
		" " +
		kernel.Main.GetConfig(kernel.CoreService, kernel.CoreVersion).(string))
	c.NewURLBuilderAbs = func() *api.URLBuilder { return api.NewURLBuilder(baseURL, 'h') }
}

func (c *Configuration) Marshal(q *query.Query, ml []*meta.Meta) []byte {
	rssPublished := encoding.LastUpdated(ml, time.RFC1123Z)

	atomLink := ""
	if s := q.String(); s != "" {
		atomLink = c.NewURLBuilderAbs().AppendQuery(s).String()
	}
	var buf bytes.Buffer
	buf.WriteString(`<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">` + "\n<channel>\n")
	xml.WriteTag(&buf, "  ", "title", c.Title)
	xml.WriteTag(&buf, "  ", "link", c.NewURLBuilderAbs().String())
	xml.WriteTag(&buf, "  ", "description", "")
	xml.WriteTag(&buf, "  ", "language", c.Language)
	xml.WriteTag(&buf, "  ", "copyright", c.Copyright)
	if rssPublished != "" {
		xml.WriteTag(&buf, "  ", "pubDate", rssPublished)
		xml.WriteTag(&buf, "  ", "lastBuildDate", rssPublished)
	}
	xml.WriteTag(&buf, "  ", "generator", c.Generator)
	buf.WriteString("  <docs>https://www.rssboard.org/rss-specification</docs>\n")
	if atomLink != "" {
		buf.WriteString(`  <atom:link href="`)
		strfun.XMLEscape(&buf, atomLink)
		buf.WriteString(`" rel="self" type="application/rss+xml"></atom:link>` + "\n")
	}
	for _, m := range ml {
		c.marshalMeta(&buf, m)
	}

	buf.WriteString("</channel>\n</rss>")
	return buf.Bytes()
}

func (c *Configuration) marshalMeta(buf *bytes.Buffer, m *meta.Meta) {
	itemPublished := ""
	if val, found := m.Get(api.KeyPublished); found {
		if published, err := time.ParseInLocation(id.TimestampLayout, val, time.Local); err == nil {
			itemPublished = published.UTC().Format(time.RFC1123Z)
		}
	}

	link := c.NewURLBuilderAbs().SetZid(m.Zid.ZettelID()).String()

	buf.WriteString("  <item>\n")
	xml.WriteTag(buf, "    ", "title", encoding.TitleAsText(m))
	xml.WriteTag(buf, "    ", "link", link)
	xml.WriteTag(buf, "    ", "guid", link)
	if itemPublished != "" {
		xml.WriteTag(buf, "    ", "pubDate", itemPublished)
	}
	marshalTags(buf, m)
	buf.WriteString("  </item>\n")
}

func marshalTags(buf *bytes.Buffer, m *meta.Meta) {
	if tags, found := m.GetList(api.KeyTags); found && len(tags) > 0 {
		for _, tag := range tags {
			for len(tag) > 0 && tag[0] == '#' {
				tag = tag[1:]
			}
			if tag != "" {
				xml.WriteTag(buf, "    ", "category", tag)
			}
		}
	}
}

//-----------------------------------------------------------------------------
// Copyright (c) 2022-present Detlef Stern
//
// This file is part of Zettelstore.
//
// Zettelstore is licensed under the latest version of the EUPL (European Union
// Public License). Please see file LICENSE.txt for your rights and obligations
// under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2022-present Detlef Stern
//-----------------------------------------------------------------------------

// Package xml provides helper for a XML-based encoding.
package xml

import (
	"bytes"

	"zettelstore.de/z/strfun"
)

// Header contains the string that should start all XML documents.
const Header = `<?xml version="1.0" encoding="UTF-8"?>` + "\n"

// WriteTag writes a simple XML tag with a given prefix and a specific value.
func WriteTag(buf *bytes.Buffer, prefix, tag, value string) {
	buf.WriteString(prefix)
	buf.WriteByte('<')
	buf.WriteString(tag)
	buf.WriteByte('>')
	strfun.XMLEscape(buf, value)
	buf.WriteString("</")
	buf.WriteString(tag)
	buf.WriteString(">\n")
}

	ml, err := e.port.QueryMeta(e.ctx, q)
	if err != nil {
		if errors.Is(err, &box.ErrNotAllowed{}) {
			return nil
		}
		return makeBlockNode(createInlineErrorText(nil, "Unable", "to", "search", "zettel"))
	}
	result, _ := QueryAction(e.ctx, q, ml, e.rtConfig)
	if result != nil {
		ast.Walk(e, result)
	}
	return result
}

func (e *evaluator) checkMaxTransclusions(ref *ast.Reference) ast.InlineNode {

	"slices"
	"strconv"
	"strings"

	"t73f.de/r/zsc/api"
	"t73f.de/r/zsc/attrs"
	"zettelstore.de/z/ast"
	"zettelstore.de/z/config"
	"zettelstore.de/z/encoding/atom"
	"zettelstore.de/z/encoding/rss"
	"zettelstore.de/z/parser"
	"zettelstore.de/z/query"
	"zettelstore.de/z/zettel/meta"
)

// QueryAction transforms a list of metadata according to query actions into a AST nested list.
func QueryAction(ctx context.Context, q *query.Query, ml []*meta.Meta, rtConfig config.Config) (ast.BlockNode, int) {
	ap := actionPara{
		ctx:   ctx,
		q:     q,
		ml:    ml,
		kind:  ast.NestedListUnordered,
		min:   -1,
		max:   -1,
		title: rtConfig.GetSiteName(),
	}
	actions := q.Actions()
	if len(actions) == 0 {
		return ap.createBlockNodeMeta("")
	}

	acts := make([]string, 0, len(actions))
	for i, act := range actions {
		if strings.HasPrefix(act, api.NumberedAction[0:1]) {
			ap.kind = ast.NestedListOrdered
			continue
		}
		if strings.HasPrefix(act, api.MinAction) {
			if num, err := strconv.Atoi(act[3:]); err == nil && num > 0 {
				ap.min = num
				continue
			}
		}
		if strings.HasPrefix(act, api.MaxAction) {
			if num, err := strconv.Atoi(act[3:]); err == nil && num > 0 {
				ap.max = num
				continue
			}
		}
		if act == api.TitleAction && i+1 < len(actions) {
			ap.title = strings.Join(actions[i+1:], " ")
			break
		}
		if act == api.ReIndexAction {
			continue
		}
		acts = append(acts, act)
	}
	var firstUnknowAct string
	for _, act := range acts {
		switch act {
		case api.AtomAction:
			return ap.createBlockNodeAtom(rtConfig)
		case api.RSSAction:
			return ap.createBlockNodeRSS(rtConfig)
		case api.KeysAction:
			return ap.createBlockNodeMetaKeys()
		}
		key := strings.ToLower(act)
		switch meta.Type(key) {
		case meta.TypeWord:
			return ap.createBlockNodeWord(key)

	if bn != nil && numItems == 0 && firstUnknowAct == strings.ToUpper(firstUnknowAct) {
		bn, numItems = ap.createBlockNodeMeta("")
	}
	return bn, numItems
}

type actionPara struct {
	ctx   context.Context
	q     *query.Query
	ml    []*meta.Meta
	kind  ast.NestedListKind
	min   int
	max   int
	title string
}

func (ap *actionPara) createBlockNodeWord(key string) (ast.BlockNode, int) {
	var buf bytes.Buffer
	ccs, bufLen := ap.prepareCatAction(key, &buf)
	if len(ccs) == 0 {
		return nil, 0

		)
		buf.Truncate(bufLen)
	}
	return &ast.ParaNode{Inlines: para}, len(ccs)
}

func (ap *actionPara) limitTags(ccs meta.CountedCategories) meta.CountedCategories {
	if min, max := ap.min, ap.max; min > 0 || max > 0 {
		if min < 0 {
			min = ccs[len(ccs)-1].Count
		}
		if max < 0 {
			max = ccs[0].Count
		}
		if ccs[len(ccs)-1].Count < min || max < ccs[0].Count {
			temp := make(meta.CountedCategories, 0, len(ccs))
			for _, cat := range ccs {
				if min <= cat.Count && cat.Count <= max {
					temp = append(temp, cat)
				}
			}
			return temp
		}
	}
	return ccs

			}
		}
	}
	return result
}

func calcBudget(total, curSize float64) float64 { return math.Round(total / (fontSizes64 - curSize)) }

func (ap *actionPara) createBlockNodeRSS(cfg config.Config) (ast.BlockNode, int) {
	var rssConfig rss.Configuration
	rssConfig.Setup(ap.ctx, cfg)
	rssConfig.Title = ap.title
	data := rssConfig.Marshal(ap.q, ap.ml)

	return &ast.VerbatimNode{
		Kind:    ast.VerbatimProg,
		Attrs:   attrs.Attributes{"lang": "xml"},
		Content: data,
	}, len(ap.ml)
}

func (ap *actionPara) createBlockNodeAtom(cfg config.Config) (ast.BlockNode, int) {
	var atomConfig atom.Configuration
	atomConfig.Setup(cfg)
	atomConfig.Title = ap.title
	data := atomConfig.Marshal(ap.q, ap.ml)

	return &ast.VerbatimNode{
		Kind:    ast.VerbatimProg,
		Attrs:   attrs.Attributes{"lang": "xml"},
		Content: data,
	}, len(ap.ml)
}

module zettelstore.de/z

go 1.22

require (
	github.com/fsnotify/fsnotify v1.7.0
	github.com/yuin/goldmark v1.7.4
	golang.org/x/crypto v0.25.0
	golang.org/x/term v0.22.0
	golang.org/x/text v0.16.0
	t73f.de/r/sx v0.0.0-20240513163553-ec4fcc6539ca
	t73f.de/r/sxwebs v0.0.0-20240613142113-66fc5a284245
	t73f.de/r/zsc v0.0.0-20240711144034-b141c81ad9b7
)

require (
	golang.org/x/sys v0.22.0 // indirect
	t73f.de/r/webs v0.0.0-20240617100047-8730e9917915 // indirect
)

github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
github.com/yuin/goldmark v1.7.4 h1:BDXOHExt+A7gwPCJgPIIq7ENvceR7we7rOS9TNoLZeg=
github.com/yuin/goldmark v1.7.4/go.mod h1:uzxRWxtg69N339t3louHJ7+O03ezfj6PlliRlaOzY1E=
golang.org/x/crypto v0.25.0 h1:ypSNr+bnYL2YhwoMt2zPxHFmbAN1KZs/njMG3hxUp30=
golang.org/x/crypto v0.25.0/go.mod h1:T+wALwcMOSE0kXgUAnPAHqTLW+XHgcELELW8VaDgm/M=
golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
golang.org/x/term v0.22.0 h1:BbsgPEJULsl2fV/AT3v15Mjva5yXKQDyKf+TbDz7QJk=
golang.org/x/term v0.22.0/go.mod h1:F3qCibpT5AMpCRfhfT53vVJwhLtIVHhB9XDjfFvnMI4=
golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
t73f.de/r/sx v0.0.0-20240513163553-ec4fcc6539ca h1:vvDqiuUfBLf+t/gpiSyqIFAdvZ7FLigOH38bqMY+v8k=
t73f.de/r/sx v0.0.0-20240513163553-ec4fcc6539ca/go.mod h1:G9pD1j2R6y9ZkPBb81mSnmwaAvTOg7r6jKp/OF7WeFA=
t73f.de/r/sxwebs v0.0.0-20240613142113-66fc5a284245 h1:raE7KUgoGsp2DzXOko9dDXEsSJ/VvoXCDYeICx7i6uo=
t73f.de/r/sxwebs v0.0.0-20240613142113-66fc5a284245/go.mod h1:ErPBVUyE2fOktL/8M7lp/PR93wP/o9RawMajB1uSqj8=
t73f.de/r/webs v0.0.0-20240617100047-8730e9917915 h1:rwUaPBIH3shrUIkmw51f4RyCplsCU+ISZHailsLiHTE=
t73f.de/r/webs v0.0.0-20240617100047-8730e9917915/go.mod h1:UGAAtul0TK5ACeZ6zTS3SX6GqwMFXxlUpHiV8oqNq5w=
t73f.de/r/zsc v0.0.0-20240711144034-b141c81ad9b7 h1:Ysb9nud8uhB4N1hUMW3GmFvWabo1r6UlcG/DhhubyCQ=
t73f.de/r/zsc v0.0.0-20240711144034-b141c81ad9b7/go.mod h1:FH9nouOzCHoR0Nbk6gBK31gGJqQI8dGVXoyGI45yHkM=

		keySiteName:         {"Site name", parseString, true},
		keyYAMLHeader:       {"YAML header", parseBool, true},
		keyZettelFileSyntax: {
			"Zettel file syntax",
			func(val string) (any, error) { return strings.Fields(val), nil },
			true,
		},
		kernel.ConfigSimpleMode:        {"Simple mode", cs.noFrozen(parseBool), true},
		config.KeyShowBackLinks:        {"Show back links", parseString, true},
		config.KeyShowFolgeLinks:       {"Show folge links", parseString, true},
		config.KeyShowSubordinateLinks: {"Show subordinate links", parseString, true},
		config.KeyShowSuccessorLinks:   {"Show successor links", parseString, true},
	}
	cs.next = interfaceMap{
		keyDefaultCopyright:            "",
		keyDefaultLicense:              "",
		keyDefaultVisibility:           meta.VisibilityLogin,
		keyExpertMode:                  false,
		config.KeyFooterZettel:         id.Invalid,
		config.KeyHomeZettel:           id.DefaultHomeZid,
		kernel.ConfigInsecureHTML:      config.NoHTML,
		api.KeyLang:                    api.ValueLangEN,
		keyMaxTransclusions:            int64(1024),
		keySiteName:                    "Zettelstore",
		keyYAMLHeader:                  false,
		keyZettelFileSyntax:            nil,
		kernel.ConfigSimpleMode:        false,
		config.KeyShowBackLinks:        "",
		config.KeyShowFolgeLinks:       "",
		config.KeyShowSubordinateLinks: "",
		config.KeyShowSuccessorLinks:   "",
	}
}
func (cs *configService) GetLogger() *logger.Logger { return cs.logger }

func (cs *configService) Start(*myKernel) error {
	cs.logger.Info().Msg("Start Service")
	data := meta.New(id.ConfigurationZid)

	}
	cs.mxService.Unlock()
	cs.SwitchNextToCur() // Poor man's restart
	return nil
}

func (cs *configService) observe(ci box.UpdateInfo) {
	if ci.Reason != box.OnZettel || ci.Zid == id.ConfigurationZid {
		cs.logger.Debug().Uint("reason", uint64(ci.Reason)).Zid(ci.Zid).Msg("observe")
		go func() {
			cs.mxService.RLock()
			mgr := cs.manager
			cs.mxService.RUnlock()
			if mgr != nil {
				cs.doUpdate(mgr)

	"bye": {
		"end this session",
		func(*cmdSession, string, []string) bool { return false },
	},
	"config": {"show configuration keys", cmdConfig},
	"crlf": {
		"toggle crlf mode",
		func(sess *cmdSession, cmd string, args []string) bool {
			if len(sess.eol) == 1 {
				sess.eol = []byte{'\r', '\n'}
				sess.println("crlf is on")
			} else {
				sess.eol = []byte{'\n'}
				sess.println("crlf is off")
			}
			return true
		},
	},
	"dump-index":   {"writes the content of the index", cmdDumpIndex},
	"dump-recover": {"show data of last recovery", cmdDumpRecover},
	"echo": {
		"toggle echo mode",
		func(sess *cmdSession, cmd string, args []string) bool {
			sess.echo = !sess.echo
			if sess.echo {
				sess.println("echo is on")
			} else {
				sess.println("echo is off")
			}
			return true
		},
	},
	"end-profile": {"stop profiling", cmdEndProfile},
	"env":         {"show environment values", cmdEnvironment},
	"get-config":  {"show current configuration data", cmdGetConfig},
	"header": {
		"toggle table header",
		func(sess *cmdSession, cmd string, args []string) bool {
			sess.header = !sess.header
			if sess.header {
				sess.println("header are on")
			} else {
				sess.println("header are off")
			}
			return true
		},
	},
	"log-level":   {"get/set log level", cmdLogLevel},
	"metrics":     {"show Go runtime metrics", cmdMetrics},
	"next-config": {"show next configuration data", cmdNextConfig},
	"profile":     {"start profiling", cmdProfile},
	"refresh":     {"refresh box data", cmdRefresh},
	"restart":     {"restart service", cmdRestart},
	"services":    {"show available services", cmdServices},
	"set-config":  {"set next configuration data", cmdSetConfig},
	"shutdown": {
		"shutdown Zettelstore",
		func(sess *cmdSession, cmd string, args []string) bool { sess.kern.Shutdown(false); return false },
	},
	"start": {"start service", cmdStart},
	"stat":  {"show service statistics", cmdStat},
	"stop":  {"stop service", cmdStop},
}

func cmdHelp(sess *cmdSession, _ string, _ []string) bool {

	if err != nil {
		sess.println(err.Error())
	}
	return true
}

func cmdStop(sess *cmdSession, cmd string, args []string) bool {
	srvnum, ok := lookupService(sess, cmd, args)
	if !ok {
		return true
	}
	err := sess.kern.doStopService(srvnum)
	if err != nil {
		sess.println(err.Error())
	}
	return true
}

func cmdStat(sess *cmdSession, cmd string, args []string) bool {
	if len(args) == 0 {
		sess.usage(cmd, "SERVICE")

	case '0', 'f', 'F', 'n', 'N':
		return false, nil
	}
	return true, nil
}

func parseInt64(val string) (any, error) {
	if u64, err := strconv.ParseInt(val, 10, 64); err == nil {

		return u64, nil
	} else {
		return nil, err
	}
}

func parseZid(val string) (any, error) {
	if zid, err := id.Parse(val); err == nil {

		return zid, nil
	} else {
		return id.Invalid, err
	}
}

func parseInvalidZid(val string) (any, error) {
	zid, _ := id.Parse(val)
	return zid, nil
}

			return err
		}
		srv.SwitchNextToCur()
	}
	return nil
}

func (kern *myKernel) StopService(srvnum kernel.Service) error {
	kern.mx.Lock()
	defer kern.mx.Unlock()
	return kern.doStopService(srvnum)
}

func (kern *myKernel) doStopService(srvnum kernel.Service) error {
	for _, srv := range kern.sortDependency(srvnum, kern.depStop, false) {
		srv.Stop(kern)
	}
	return nil
}

func (kern *myKernel) sortDependency(
	srvnum kernel.Service,
	srvdeps serviceDependency,
	isStarted bool,
) []service {

// --- The kernel as a service -------------------------------------------

type kernelService struct {
	kernel *myKernel
}

func (*kernelService) Initialize(*logger.Logger)                        {}
func (ks *kernelService) GetLogger() *logger.Logger                     { return ks.kernel.logger }
func (*kernelService) ConfigDescriptions() []serviceConfigDescription   { return nil }
func (*kernelService) SetConfig(key, value string) error                { return errAlreadyFrozen }
func (*kernelService) GetCurConfig(key string) interface{}              { return nil }
func (*kernelService) GetNextConfig(key string) interface{}             { return nil }
func (*kernelService) GetCurConfigList(all bool) []kernel.KeyDescrValue { return nil }
func (*kernelService) GetNextConfigList() []kernel.KeyDescrValue        { return nil }
func (*kernelService) GetStatistics() []kernel.KeyValue                 { return nil }
func (*kernelService) Freeze()                                          {}
func (*kernelService) Start(*myKernel) error                            { return nil }
func (*kernelService) SwitchNextToCur()                                 {}
func (*kernelService) IsStarted() bool                                  { return true }
func (*kernelService) Stop(*myKernel)                                   {}

func (ws *webService) Initialize(logger *logger.Logger) {
	ws.logger = logger
	ws.descr = descriptionMap{
		kernel.WebAssetDir: {
			"Asset file  directory",
			func(val string) (any, error) {
				val = filepath.Clean(val)

				if finfo, err := os.Stat(val); err == nil && finfo.IsDir() {
					return val, nil
				} else {
					return nil, err
				}
			},
			true,
		},
		kernel.WebBaseURL: {
			"Base URL",
			func(val string) (any, error) {
				if _, err := url.Parse(val); err != nil {

					return "", err
				}
				return ap.String(), nil
			},
			true},
		kernel.WebMaxRequestSize:   {"Max Request Size", parseInt64, true},
		kernel.WebPersistentCookie: {"Persistent cookie", parseBool, true},

		kernel.WebSecureCookie:     {"Secure cookie", parseBool, true},
		kernel.WebTokenLifetimeAPI: {
			"Token lifetime API",
			makeDurationParser(10*time.Minute, 0, 1*time.Hour),
			true,
		},
		kernel.WebTokenLifetimeHTML: {

	ws.next = interfaceMap{
		kernel.WebAssetDir:          "",
		kernel.WebBaseURL:           "http://127.0.0.1:23123/",
		kernel.WebListenAddress:     "127.0.0.1:23123",
		kernel.WebMaxRequestSize:    int64(16 * 1024 * 1024),
		kernel.WebPersistentCookie:  false,
		kernel.WebSecureCookie:      true,

		kernel.WebTokenLifetimeAPI:  1 * time.Hour,
		kernel.WebTokenLifetimeHTML: 10 * time.Minute,
		kernel.WebURLPrefix:         "/",
	}
}

func makeDurationParser(defDur, minDur, maxDur time.Duration) parseFunc {

func (ws *webService) Start(kern *myKernel) error {
	baseURL := ws.GetNextConfig(kernel.WebBaseURL).(string)
	listenAddr := ws.GetNextConfig(kernel.WebListenAddress).(string)
	urlPrefix := ws.GetNextConfig(kernel.WebURLPrefix).(string)
	persistentCookie := ws.GetNextConfig(kernel.WebPersistentCookie).(bool)
	secureCookie := ws.GetNextConfig(kernel.WebSecureCookie).(bool)

	maxRequestSize := ws.GetNextConfig(kernel.WebMaxRequestSize).(int64)
	if maxRequestSize < 1024 {
		maxRequestSize = 1024
	}

	if !strings.HasSuffix(baseURL, urlPrefix) {
		ws.logger.Error().Str("base-url", baseURL).Str("url-prefix", urlPrefix).Msg(
			"url-prefix is not a suffix of base-url")
		return errWrongBasePrefix
	}

	if lap := netip.MustParseAddrPort(listenAddr); !kern.auth.manager.WithAuth() && !lap.Addr().IsLoopback() {
		ws.logger.Info().Str("listen", listenAddr).Msg("service may be reached from outside, but authentication is not enabled")
	}












	srvw := impl.New(ws.logger, listenAddr, baseURL, urlPrefix, persistentCookie, secureCookie, maxRequestSize, kern.auth.manager)
	err := kern.web.setupServer(srvw, kern.box.manager, kern.auth.manager, &kern.cfg)
	if err != nil {
		ws.logger.Error().Err(err).Msg("Unable to create")
		return err
	}
	if kern.core.GetNextConfig(kernel.CoreDebug).(bool) {
		srvw.SetDebug()

	// StartService start the given service.
	StartService(Service) error

	// RestartService stops and restarts the given service, while maintaining service dependencies.
	RestartService(Service) error

	// StopService stop the given service.
	StopService(Service) error

	// GetServiceStatistics returns a key/value list with statistical data.
	GetServiceStatistics(Service) []KeyValue

	// DumpIndex writes some data about the internal index into a writer.
	DumpIndex(io.Writer)

// Constants for web service keys.
const (
	WebAssetDir          = "asset-dir"
	WebBaseURL           = "base-url"
	WebListenAddress     = "listen"
	WebPersistentCookie  = "persistent"

	WebMaxRequestSize    = "max-request-size"
	WebSecureCookie      = "secure"
	WebTokenLifetimeAPI  = "api-lifetime"
	WebTokenLifetimeHTML = "html-lifetime"
	WebURLPrefix         = "prefix"
)

	if lastPos < len(text) {
		sb.Write(text[lastPos:])
	}
	return sb.String()
}

func (p *mdP) acceptCodeSpan(node *gmAst.CodeSpan) ast.InlineSlice {


























	return ast.InlineSlice{
		&ast.LiteralNode{
			Kind:    ast.LiteralProg,
			Attrs:   nil, //TODO
			Content: cleanCodeSpan(node.Text(p.source)),
		},
	}
}

func cleanCodeSpan(text []byte) []byte {
	if len(text) == 0 {
		return nil
	}
	lastPos := 0
	var buf bytes.Buffer
	for pos, ch := range text {
		if ch == '\n' {
			buf.Write(text[lastPos:pos])
			if pos < len(text)-1 {
				buf.WriteByte(' ')
			}
			lastPos = pos + 1
		}
	}
	buf.Write(text[lastPos:])
	return buf.Bytes()
}

func (p *mdP) acceptEmphasis(node *gmAst.Emphasis) ast.InlineSlice {
	kind := ast.FormatEmph
	if node.Level == 2 {
		kind = ast.FormatStrong
	}
	return ast.InlineSlice{

//-----------------------------------------------------------------------------

// Package plain provides a parser for plain text data.
package plain

import (
	"bytes"
	"strings"

	"t73f.de/r/sx/sxreader"
	"t73f.de/r/zsc/attrs"
	"t73f.de/r/zsc/input"
	"zettelstore.de/z/ast"
	"zettelstore.de/z/parser"
	"zettelstore.de/z/zettel/meta"

	return ast.InlineSlice{&ast.EmbedBLOBNode{
		Blob:   []byte(svgSrc),
		Syntax: syntax,
	}}
}

func scanSVG(inp *input.Input) string {
	for input.IsSpace(inp.Ch) {
		inp.Next()
	}
	svgSrc := string(inp.Src[inp.Pos:])
	if !strings.HasPrefix(svgSrc, "<svg ") {
		return ""
	}


	// TODO: check proper end </svg>


	return svgSrc
}

func parseSxnBlocks(inp *input.Input, _ *meta.Meta, syntax string) ast.BlockSlice {
	rd := sxreader.MakeReader(bytes.NewReader(inp.Src))
	_, err := rd.ReadAll()
	result := ast.BlockSlice{
		&ast.VerbatimNode{