Zettelstore

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# zettelstore
# Zettelstore

**Zettelstore** is a software that collects and relates your notes
(“zettel”) to represent and enhance your knowledge. It helps with
many tasks of personal knowledge management by explicitly supporting the
[Zettelkasten method](https://en.wikipedia.org/wiki/Zettelkasten). The method
is based on creating many individual notes, each with one idea or information,
that are related to each other. Since knowledge is typically build up
gradually, one major focus is a long-term store of these notes, hence the name
“Zettelstore”.
A storage and service for zettel notes.

To get an initial impression, take a look at the
[manual](https://zettelstore.de/manual/). It is a live example of the
zettelstore software, running in read-only mode.

The software, including the manual, is licensed
under the [European Union Public License 1.2 (or
later)](https://zettelstore.de/home/file?name=LICENSE.txt&ci=trunk).

[Stay tuned](https://twitter.com/zettelstore)…

0.0.10
0.0.11

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

// ZettelNode is the root node of the abstract syntax tree.
// It is *not* part of the visitor pattern.
type ZettelNode struct {
	Zettel  domain.Zettel
	Zid     id.Zid      // Zettel identification.
	InhMeta *meta.Meta  // Meta data of the zettel, with inherited values.
	// Zettel  domain.Zettel
	Meta    *meta.Meta     // Original metadata
	Content domain.Content // Original content
	Zid     id.Zid         // Zettel identification.
	InhMeta *meta.Meta     // Metadata of the zettel, with inherited values.
	Title   InlineSlice // Zettel title is a sequence of inline nodes.
	Ast     BlockSlice  // Zettel abstract syntax tree is a sequence of block nodes.
	Ast     BlockSlice     // Zettel abstract syntax tree is a sequence of block nodes.
}

// Node is the interface, all nodes must implement.
type Node interface {
	Accept(v Visitor)
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

func (tn *TableNode) blockNode() {}

// Accept a visitor and visit the node.
func (tn *TableNode) Accept(v Visitor) { v.VisitTable(tn) }

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

// BLOBNode contains just binary data that must be interpreted accordung to
// BLOBNode contains just binary data that must be interpreted according to
// a syntax.
type BLOBNode struct {
	Title  string
	Syntax string
	Blob   []byte
}

func (bn *BLOBNode) blockNode() {}

// Accept a visitor and visit the node.
func (bn *BLOBNode) Accept(v Visitor) { v.VisitBLOB(bn) }

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

// VisitVerbatim has nothing to traverse.
func (t TopDownTraverser) VisitVerbatim(vn *VerbatimNode) { t.v.VisitVerbatim(vn) }

// VisitRegion traverses the content and the additional text.
func (t TopDownTraverser) VisitRegion(rn *RegionNode) {
	t.v.VisitRegion(rn)
	t.VisitBlockSlice(rn.Blocks)
	t.visitInlineSlice(rn.Inlines)
	t.VisitInlineSlice(rn.Inlines)
}

// VisitHeading traverses the heading.
func (t TopDownTraverser) VisitHeading(hn *HeadingNode) {
	t.v.VisitHeading(hn)
	t.visitInlineSlice(hn.Inlines)
	t.VisitInlineSlice(hn.Inlines)
}

// VisitHRule traverses nothing.
func (t TopDownTraverser) VisitHRule(hn *HRuleNode) { t.v.VisitHRule(hn) }

// VisitNestedList traverses all nested list elements.
func (t TopDownTraverser) VisitNestedList(ln *NestedListNode) {
	t.v.VisitNestedList(ln)
	for _, item := range ln.Items {
		t.visitItemSlice(item)
	}
}

// VisitDescriptionList traverses all description terms and their associated
// descriptions.
func (t TopDownTraverser) VisitDescriptionList(dn *DescriptionListNode) {
	t.v.VisitDescriptionList(dn)
	for _, defs := range dn.Descriptions {
		t.visitInlineSlice(defs.Term)
		t.VisitInlineSlice(defs.Term)
		for _, descr := range defs.Descriptions {
			t.visitDescriptionSlice(descr)
		}
	}
}

// VisitPara traverses the inlines of a paragraph.
func (t TopDownTraverser) VisitPara(pn *ParaNode) {
	t.v.VisitPara(pn)
	t.visitInlineSlice(pn.Inlines)
	t.VisitInlineSlice(pn.Inlines)
}

// VisitTable traverses all cells of the header and then row-wise all cells of
// the table body.
func (t TopDownTraverser) VisitTable(tn *TableNode) {
	t.v.VisitTable(tn)
	for _, col := range tn.Header {
		t.visitInlineSlice(col.Inlines)
		t.VisitInlineSlice(col.Inlines)
	}
	for _, row := range tn.Rows {
		for _, col := range row {
			t.visitInlineSlice(col.Inlines)
			t.VisitInlineSlice(col.Inlines)
		}
	}
}

// VisitBLOB traverses nothing.
func (t TopDownTraverser) VisitBLOB(bn *BLOBNode) { t.v.VisitBLOB(bn) }

// VisitBreak traverses nothing.
func (t TopDownTraverser) VisitBreak(bn *BreakNode) { t.v.VisitBreak(bn) }

// VisitLink traverses the link text.
func (t TopDownTraverser) VisitLink(ln *LinkNode) {
	t.v.VisitLink(ln)
	t.visitInlineSlice(ln.Inlines)
	t.VisitInlineSlice(ln.Inlines)
}

// VisitImage traverses the image text.
func (t TopDownTraverser) VisitImage(in *ImageNode) {
	t.v.VisitImage(in)
	t.visitInlineSlice(in.Inlines)
	t.VisitInlineSlice(in.Inlines)
}

// VisitCite traverses the cite text.
func (t TopDownTraverser) VisitCite(cn *CiteNode) {
	t.v.VisitCite(cn)
	t.visitInlineSlice(cn.Inlines)
	t.VisitInlineSlice(cn.Inlines)
}

// VisitFootnote traverses the footnote text.
func (t TopDownTraverser) VisitFootnote(fn *FootnoteNode) {
	t.v.VisitFootnote(fn)
	t.visitInlineSlice(fn.Inlines)
	t.VisitInlineSlice(fn.Inlines)
}

// VisitMark traverses nothing.
func (t TopDownTraverser) VisitMark(mn *MarkNode) { t.v.VisitMark(mn) }

// VisitFormat traverses the formatted text.
func (t TopDownTraverser) VisitFormat(fn *FormatNode) {
	t.v.VisitFormat(fn)
	t.visitInlineSlice(fn.Inlines)
	t.VisitInlineSlice(fn.Inlines)
}

// VisitLiteral traverses nothing.
func (t TopDownTraverser) VisitLiteral(ln *LiteralNode) { t.v.VisitLiteral(ln) }

// VisitBlockSlice traverses a block slice.
func (t TopDownTraverser) VisitBlockSlice(bns BlockSlice) {

func (t TopDownTraverser) visitDescriptionSlice(dns DescriptionSlice) {
	for _, dn := range dns {
		dn.Accept(t)
	}
}

// VisitInlineSlice traverses a block slice.
func (t TopDownTraverser) visitInlineSlice(ins InlineSlice) {
func (t TopDownTraverser) VisitInlineSlice(ins InlineSlice) {
	for _, in := range ins {
		in.Accept(t)
	}
}

import (
	"context"

	"zettelstore.de/z/domain"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/place"
	"zettelstore.de/z/search"
	"zettelstore.de/z/web/session"
)

// PlaceWithPolicy wraps the given place inside a policy place.
func PlaceWithPolicy(
	place place.Place,
	simpleMode bool,

	return nil, place.NewErrNotAllowed("GetMeta", user, zid)
}

func (pp *polPlace) FetchZids(ctx context.Context) (id.Set, error) {
	return nil, place.NewErrNotAllowed("fetch-zids", session.GetUser(ctx), id.Invalid)
}

func (pp *polPlace) SelectMeta(
func (pp *polPlace) SelectMeta(ctx context.Context, s *search.Search) ([]*meta.Meta, error) {
	ctx context.Context, f *place.Filter, s *place.Sorter) ([]*meta.Meta, error) {
	user := session.GetUser(ctx)
	f = place.EnsureFilter(f)
	canRead := pp.policy.CanRead
	if sel := f.Select; sel != nil {
		f.Select = func(m *meta.Meta) bool {
			return canRead(user, m) && sel(m)
		}
	} else {
		f.Select = func(m *meta.Meta) bool {
			return canRead(user, m)
	s = s.AddPreMatch(func(m *meta.Meta) bool { return canRead(user, m) })
		}
	}
	result, err := pp.place.SelectMeta(ctx, f, s)
	return pp.place.SelectMeta(ctx, s)
	return result, err
}

func (pp *polPlace) CanUpdateZettel(ctx context.Context, zettel domain.Zettel) bool {
	return pp.place.CanUpdateZettel(ctx, zettel)
}

func (pp *polPlace) UpdateZettel(ctx context.Context, zettel domain.Zettel) error {

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

package cmd

import (
	"flag"
	"fmt"
	"io/ioutil"
	"io"
	"os"

	"zettelstore.de/z/config/runtime"
	"zettelstore.de/z/domain"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"

	z := parser.ParseZettel(
		domain.Zettel{
			Meta:    meta,
			Content: domain.NewContent(inp.Src[inp.Pos:]),
		},
		runtime.GetSyntax(meta),
	)
	enc := encoder.Create(
	enc := encoder.Create(format, &encoder.Environment{Lang: runtime.GetLang(meta)})
		format,
		&encoder.StringOption{Key: "lang", Value: runtime.GetLang(meta)},
	)
	if enc == nil {
		fmt.Fprintf(os.Stderr, "Unknown format %q\n", format)
		return 2, nil
	}
	_, err = enc.WriteZettel(os.Stdout, z, format != "raw")
	if err != nil {
		return 2, err
	}
	fmt.Println()

	return 0, nil
}

func getInput(args []string) (*meta.Meta, *input.Input, error) {
	if len(args) < 1 {
		src, err := ioutil.ReadAll(os.Stdin)
		src, err := io.ReadAll(os.Stdin)
		if err != nil {
			return nil, nil, err
		}
		inp := input.NewInput(string(src))
		m := meta.NewFromInput(id.New(true), inp)
		return m, inp, nil
	}

	src, err := ioutil.ReadFile(args[0])
	src, err := os.ReadFile(args[0])
	if err != nil {
		return nil, nil, err
	}
	inp := input.NewInput(string(src))
	m := meta.NewFromInput(id.New(true), inp)

	if len(args) > 1 {
		src, err := ioutil.ReadFile(args[1])
		src, err := os.ReadFile(args[1])
		if err != nil {
			return nil, nil, err
		}
		inp = input.NewInput(string(src))
	}
	return m, inp, nil
}

package cmd

import (
	"flag"
	"fmt"
	"os"

	"golang.org/x/crypto/ssh/terminal"
	"golang.org/x/term"

	"zettelstore.de/z/auth/cred"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"
)

// ---------- Subcommand: password -------------------------------------------

		meta.KeyUserID, ident,
	)
	return 0, nil
}

func getPassword(prompt string) (string, error) {
	fmt.Fprintf(os.Stderr, "%s: ", prompt)
	password, err := terminal.ReadPassword(int(os.Stdin.Fd()))
	password, err := term.ReadPassword(int(os.Stdin.Fd()))
	fmt.Fprintln(os.Stderr)
	return string(password), err
}

	ucParseZettel := usecase.NewParseZettel(ucGetZettel)
	ucListMeta := usecase.NewListMeta(pp)
	ucListRoles := usecase.NewListRole(pp)
	ucListTags := usecase.NewListTags(pp)
	ucZettelContext := usecase.NewZettelContext(pp)

	router := router.NewRouter()
	router.Handle("/", webui.MakeGetRootHandler(pp))
	router.Handle("/", webui.MakeGetRootHandler(te, pp))
	router.AddListRoute('a', http.MethodGet, webui.MakeGetLoginHandler(te))
	router.AddListRoute('a', http.MethodPost, adapter.MakePostLoginHandler(
		api.MakePostLoginHandlerAPI(ucAuthenticate),
		webui.MakePostLoginHandlerHTML(te, ucAuthenticate)))
	router.AddListRoute('a', http.MethodPut, api.MakeRenewAuthHandler())
	router.AddZettelRoute('a', http.MethodGet, webui.MakeGetLogoutHandler())
	router.AddZettelRoute('a', http.MethodGet, webui.MakeGetLogoutHandler(te))
	if !readonlyMode {
		router.AddZettelRoute('b', http.MethodGet, webui.MakeGetRenameZettelHandler(
			te, ucGetMeta))
		router.AddZettelRoute('b', http.MethodPost, webui.MakePostRenameZettelHandler(
			usecase.NewRenameZettel(pp)))
			te, usecase.NewRenameZettel(pp)))
		router.AddZettelRoute('c', http.MethodGet, webui.MakeGetCopyZettelHandler(
			te, ucGetZettel, usecase.NewCopyZettel()))
		router.AddZettelRoute('c', http.MethodPost, webui.MakePostCreateZettelHandler(
			usecase.NewCreateZettel(pp)))
			te, usecase.NewCreateZettel(pp)))
		router.AddZettelRoute('d', http.MethodGet, webui.MakeGetDeleteZettelHandler(
			te, ucGetZettel))
		router.AddZettelRoute('d', http.MethodPost, webui.MakePostDeleteZettelHandler(
			usecase.NewDeleteZettel(pp)))
			te, usecase.NewDeleteZettel(pp)))
		router.AddZettelRoute('e', http.MethodGet, webui.MakeEditGetZettelHandler(
			te, ucGetZettel))
		router.AddZettelRoute('e', http.MethodPost, webui.MakeEditSetZettelHandler(
			usecase.NewUpdateZettel(pp)))
			te, usecase.NewUpdateZettel(pp)))
		router.AddZettelRoute('f', http.MethodGet, webui.MakeGetFolgeZettelHandler(
			te, ucGetZettel, usecase.NewFolgeZettel()))
		router.AddZettelRoute('f', http.MethodPost, webui.MakePostCreateZettelHandler(
			usecase.NewCreateZettel(pp)))
			te, usecase.NewCreateZettel(pp)))
		router.AddZettelRoute('g', http.MethodGet, webui.MakeGetNewZettelHandler(
			te, ucGetZettel, usecase.NewNewZettel()))
		router.AddZettelRoute('g', http.MethodPost, webui.MakePostCreateZettelHandler(
			usecase.NewCreateZettel(pp)))
			te, usecase.NewCreateZettel(pp)))
	}
	router.AddListRoute('f', http.MethodGet, webui.MakeSearchHandler(
		te, usecase.NewSearch(pp), ucGetMeta, ucGetZettel))
	router.AddListRoute('h', http.MethodGet, webui.MakeListHTMLMetaHandler(
		te, ucListMeta, ucListRoles, ucListTags))
	router.AddZettelRoute('h', http.MethodGet, webui.MakeGetHTMLZettelHandler(
		te, ucParseZettel, ucGetMeta))

package cmd

import (
	"context"
	"flag"
	"fmt"
	"io/ioutil"
	"os"
	"strings"

	"zettelstore.de/z/config/runtime"
	"zettelstore.de/z/config/startup"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"

func getConfig(fs *flag.FlagSet) (cfg *meta.Meta) {
	var configFile string
	if configFlag := fs.Lookup("c"); configFlag != nil {
		configFile = configFlag.Value.String()
	} else {
		configFile = defConfigfile
	}
	content, err := ioutil.ReadFile(configFile)
	content, err := os.ReadFile(configFile)
	if err != nil {
		cfg = meta.New(id.Invalid)
	} else {
		cfg = meta.NewFromInput(id.Invalid, input.NewInput(string(content)))
	}
	fs.Visit(func(flg *flag.Flag) {
		switch flg.Name {

	_ "zettelstore.de/z/parser/blob"       // Allow to use BLOB parser.
	_ "zettelstore.de/z/parser/markdown"   // Allow to use markdown parser.
	_ "zettelstore.de/z/parser/none"       // Allow to use none parser.
	_ "zettelstore.de/z/parser/plain"      // Allow to use plain parser.
	_ "zettelstore.de/z/parser/zettelmark" // Allow to use zettelmark parser.
	_ "zettelstore.de/z/place/constplace"  // Allow to use global internal place.
	_ "zettelstore.de/z/place/dirplace"    // Allow to use directory place.
	_ "zettelstore.de/z/place/fileplace"   // Allow to use file place.
	_ "zettelstore.de/z/place/memplace"    // Allow to use memory place.
)

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

// Package main is the starting point for the zettelstore command.
package main

import (
	"zettelstore.de/z/cmd"
import "zettelstore.de/z/cmd"
)

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

func main() {
	cmd.Main("Zettelstore", version)
}

		panic("configStock not set")
	}
	return configStock.GetMeta(id.ConfigurationZid)
}

// GetDefaultTitle returns the current value of the "default-title" key.
func GetDefaultTitle() string {
	if configStock != nil {
	if config := getConfigurationMeta(); config != nil {
		if title, ok := config.Get(meta.KeyDefaultTitle); ok {
			return title
		if config := getConfigurationMeta(); config != nil {
			if title, ok := config.Get(meta.KeyDefaultTitle); ok {
				return title
			}
		}
	}
	return "Untitled"
}

// GetDefaultSyntax returns the current value of the "default-syntax" key.
func GetDefaultSyntax() string {

func GetDefaultCopyright() string {
	if configStock != nil {
		if config := getConfigurationMeta(); config != nil {
			if copyright, ok := config.Get(meta.KeyDefaultCopyright); ok {
				return copyright
			}
		}
		// TODO: get owner
	}
	return ""
}

// GetDefaultLicense returns the current value of the "default-license" key.
func GetDefaultLicense() string {
	if configStock != nil {

id: 00000000000100
title: Zettelstore Runtime Configuration
role: configuration
syntax: none
default-copyright: (c) 2020-2021 by Detlef Stern <ds@zettelstore.de>
default-license: EUPL-1.2-or-later
default-visibility: public
footer-html: <hr><p><a href="/home/doc/trunk/www/impri.wiki">Imprint / Privacy</a></p>
home-zettel: 00001000000000
no-index: true
site-name: Zettelstore Manual
visibility: owner

id: 00001000000000
title: Zettelstore Manual
role: manual
tags: #manual #zettelstore
syntax: zmk

* [[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]]
* Troubleshooting
* Frequently asked questions

Licensed under the EUPL-1.2-or-later.

id: 00001004011200
title: Zettelstore places
role: manual
tags: #configuration #manual #zettelstore
syntax: zmk
role: manual

A Zettelstore must store its zettel somehow and somewhere.
In most cases you want to store your zettel as files in a directory.
Under certain circumstances you may want to store your zettel in other places.

An example are the [[predefined zettel|00001005090000]] that come with a Zettelstore.
They are stored within the software itself.
In another situation you may want to store your zettel volatilely, e.g. if you want to provide a sandbox for experimenting.
In another situation you may want to store your zettel volatile, e.g. if you want to provide a sandbox for experimenting.

To cope with these (and more) situations, you configure Zettelstore to use one or more places.
This is done via the ''place-X-uri'' keys of the [[start-up configuration|00001004010000#place-X-uri]] (X is a number).
Places are specified using special [[URIs|https://en.wikipedia.org/wiki/Uniform_Resource_Identifier]], somehow similar to web addresses.

The following place URIs are supported:

; ''dir:\//DIR''
: Specifies a directory where zettel files are stored.
  ''DIR'' is the file path.
  Although it is possible to use relative file paths, such as ''./zettel'' (→ URI is ''dir:\//.zettel''), it is preferable to use absolute file paths, e.g. ''/home/user/zettel''.

  The directory must exist before starting the Zettelstore[^There is one exception: when Zettelstore is [[started without any parameter|00001004050000]], e.g. via double-clicking its icon, an directory called ''./zettel'' will be created.].

  It is possible to [[configure|00001004011400]] a directory place.
; ''file:FILE.zip'' oder ''file:/\//path/to/file.zip''
: Specifies a ZIP file which contains files that store zettel.
  You can create such a ZIP file, if you zip a directory full of zettel files.

  This place is always read-only.
; ''mem:''
: Stores all its zettel in volatile memory.
  If you stop the Zettelstore, all changes are lost.
; ''const:''
: Is a place of predefined, essential zettel.

All places that you configure via the ''store-X-uri'' keys form a chain of places.
If a zettel should be retrieved, a search starts in the place specified with the ''place-1-uri'' key, then ''place-2-uri'' and so on.
If a zettel is created or changed, it is always stored in the place specified with the ''place-1-uri'' key.
This allows to overwrite zettel from other places, e.g. the predefined zettel.

If you did not configure the place of the predefined zettel (''const:'') they will automatically be appended as a last place.
Otherwise Zettelstore will not work in certain situations.

If you use the ''mem:'' place, where zettel are stored in volatile memory, it makes only sense if you configure it as ''place-1-uri''.
Such a place will be empty when Zettelstore starts and only the place 1 will receive updates.
You must make sure that your computer has enough RAM to store all zettel.

  If not given, the value ''default-license'' from the [[configuration zettel|00001004020000#default-license]] will be used.
; [!modified]''modified''
: Date and time when a zettel was modified through Zettelstore.
  If you edit a zettel with an editor software outside Zettelstore, you should set it manually to an appropriate value.

  This is a computed value.
  There is no need to set it via Zettelstore.
; [!new-role]''new-role''
: Used in a template zettel to specify the ''role'' of the new zettel.
; [!no-index]''no-index''
: If set to true, the zettel will not be indexed and therefore not be found in full-text searches.
; [!precursor]''precursor''
: References zettel for which this zettel is a ""Folgezettel"" / follow-up zettel.
  Basically the inverse of key [[''folge''|#folge]].
; [!published]''published''
: This property contains the timestamp of the mast modification / creation of the zettel.
  If [[''modified''|#modified]]is set, it contains the same value.
  Otherwise, if the zettel identifier contains a valid timestamp, the identifier is used.

A set is different to a list, as no duplicates are allowed.

=== Allowed values
Every tag must must begin with the number sign character (""''#''"", ''U+0023''), followed by at least one printable character.
Tags are separated by space characters.

=== Match operator
It depends of the first character of a search string how it is matched against a tag set value:
A value matches a tag set value, if the first value is equal to at least one tag in the tag set.

* If the first character of the search string is a number sign character,
  it must exactly match one of the values of a tag.
* In other cases, the search string must be the prefix of at least one tag.

Conpectually, all number sign characters are removed at the beginning of the search string
and of all tags.

=== Sorting
Sorting is done by comparing the [[String|00001006033500]] values.

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.
In fact, all identifiers of zettel initially provided by an empty Zettelstore
begin with ""000000"", except the home zettel ''00010000000000''.
The identifiers of zettel if this manual have be chosen to begin with ""000010"".
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.

The first zettel is the zettel that contains CSS for displaying the web interface.
This is to ensure that the web interface looks nice even for not authenticated users.
The other zettel is the zettel containing the [[version|00000000000001]] of the Zettelstore.

Please note: if authentication is not enabled, every user has the same rights as the owner of a Zettelstore.
This is also true, if the Zettelstore runs additionally in [[read-only mode|00001004010000#read-only-mode]].
In this case, the [[runtime configuration zettel|00001004020000]] is shown (its visibility is ""owner"").
The [[start-up configuration|00001004010000]] is not shown, because the associated computed zettel with identifier ''00000000000099'' is stored with the visibility ""expert"".
The [[start-up configuration|00001004010000]] is not shown, because the associated computed zettel with identifier ''00000000000098'' is stored with the visibility ""expert"".
If you want to show such a zettel, you must set ''expert-mode'' to true.

User-defined keys have the type ''e'' (string, possibly empty).

For example, if you want to retrieve all zettel that contain the string ""API"" in its title, your request will be:
```sh
# curl 'http://127.0.0.1:23123/z?title=API'
{"list":[{"id":"00001012921000","url":"/z/00001012921000","meta":{"title":"API: JSON structure of an access token","tags":"#api #manual #reference #zettelstore","syntax":"zmk","role":"manual"}},{"id":"00001012920500","url":"/z/00001012920500","meta":{"title":"Formats available by the API","tags":"#api #manual #reference #zettelstore","syntax":"zmk","role":"manual"}},{"id":"00001012920000","url":"/z/00001012920000","meta":{"title":"Endpoints used by the API","tags":"#api #manual #reference #zettelstore","syntax":"zmk","role":"manual"}}, ...
```

However, if you want all zettel that does //not// match a given value, you must prefix the value with the exclamation mark character (""!"", ''U+0021'').
For example, if you want to retrieve all zettel that do not contain the string ""API"" in their title, your request will be:
```sh
# curl 'http://127.0.0.1:23123/z?title=!API'
{"list":[{"id":"00010000000000","url":"/z/00010000000000","meta":{"back":"00001003000000 00001005090000","backward":"00001003000000 00001005090000","copyright":"(c) 2020-2021 by Detlef Stern <ds@zettelstore.de>","forward":"00000000000001 00000000000003 00000000000096 00000000000098 00000000000100","lang":"en","license":"EUPL-1.2-or-later","role":"zettel","syntax":"zmk","title":"Home"}},{"id":"00001014000000","url":"/z/00001014000000","meta":{"back":"00001000000000 00001004020000 00001012920510","backward":"00001000000000 00001004020000 00001012000000 00001012920510","copyright":"(c) 2020-2021 by Detlef Stern <ds@zettelstore.de>","forward":"00001012000000","lang":"en","license":"EUPL-1.2-or-later","published":"00001014000000","role":"manual","syntax":"zmk","tags":"#manual #webui #zettelstore","title":"Web user interface"}},
...
```
The empty query parameter values matches all zettel that contain the given metadata key.
Similar, if you specify just the exclamation mark character as a query parameter value, only those zettel match that does //not// contain the given metadata key.
For example ``curl 'http://localhost:23123/z?back=!&backward='`` returns all zettel that are reachable via other zettel, but also references these zettel.

=== Output only specific parts of a zettel
If you are just interested in the zettel identifier, you should add the ""''_part''"" query parameter:
```sh
# curl 'http://127.0.0.1:23123/z?title=API&_part=id'
{"list":[{"id":"00001012921000","url":"/z/00001012921000"},{"id":"00001012920500","url":"/z/00001012920500"},{"id":"00001012920000","url":"/z/00001012920000"},{"id":"00001012051800","url":"/z/00001012051800"},{"id":"00001012051600","url":"/z/00001012051600"},{"id":"00001012051400","url":"/z/00001012051400"},{"id":"00001012051200","url":"/z/00001012051200"},{"id":"00001012050600","url":"/z/00001012050600"},{"id":"00001012050400","url":"/z/00001012050400"},{"id":"00001012050200","url":"/z/00001012050200"},{"id":"00001012000000","url":"/z/00001012000000"}]}
```
If you want only those zettel that additionally must contain the string ""JSON"", you have to add an additional query parameter:
```sh

The query parameter ""''_offset''"" allows to list not only the first elements, but to begin at a specific element:
```sh
# curl 'http://192.168.17.7:23121/z?title=API&_part=id&_sort=id&_limit=2&_offset=1'
{"list":[{"id":"00001012050200","url":"/z/00001012050200"},{"id":"00001012050400","url":"/z/00001012050400"}]}
```

=== General filter
The query parameter ""''_s''"" allows to provide a string, which will be searched for in all metadata.
While searching, the [[type|00001006030000]] of each metadata key will be respected.
The query parameter ""''_s''"" allows to provide a string for a full-text search of all zettel.
The search string will be normalized according to Unicode NKFD, ignoring everything except letters and numbers.

You are allowed to specify this query parameter more than once.
All results will be intersected, i.e. a zettel will be included into the list if both of the provided values match.

This parameter loosely resembles the search box of the web user interface.

id: 00001012054000
title: API: Retrieve zettel order within an existing zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk

Some zettel act as a ""table of contents"" for other zettel.
The [[Home zettel|00010000000000]] of this manual is one example, the [[general API description|00001012000000]] is another.
The [[initial zettel|00001000000000]] of this manual is one example, the [[general API description|00001012000000]] is another.
Every zettel with a certain internal structure can act as the ""table of contents"" for others.

What is a ""table of contents""?
Basically, it is just a list of references to other zettel.

To retrieve the ""table of contents"", the software looks at first level [[list items|00001007030200]].
If an item contains a valid reference to a zettel, this reference will be interpreted as an item in the table of contents.

This applies only to first level list items (ordered or unordered list), but not to deeper levels.
Only the first reference to a valid zettel is collected for the table of contents.
Following references to zettel within such an list item are ignored.

To retrieve the zettel order of an existing zettel, use the [[endpoint|00001012920000]] ''/o/{ID}''.

````
# curl http://127.0.0.1:23123/o/00010000000000
{"id":"00010000000000","url":"/z/00010000000000","meta":{...},"list":[{"id":"00001001000000","url":"/z/00001001000000","meta":{...}},{"id":"00001002000000","url":"/z/00001002000000","meta":{...}},{"id":"00001003000000","url":"/z/00001003000000","meta":{...}},{"id":"00001004000000","url":"/z/00001004000000","meta":{...}},...,{"id":"00001014000000","url":"/z/00001014000000","meta":{...}}]}
# curl http://127.0.0.1:23123/o/00001000000000
{"id":"00001000000000","url":"/z/00001000000000","meta":{...},"list":[{"id":"00001001000000","url":"/z/00001001000000","meta":{...}},{"id":"00001002000000","url":"/z/00001002000000","meta":{...}},{"id":"00001003000000","url":"/z/00001003000000","meta":{...}},{"id":"00001004000000","url":"/z/00001004000000","meta":{...}},...,{"id":"00001014000000","url":"/z/00001014000000","meta":{...}}]}
````
Formatted, this translates into:[^Metadata (key ''meta'') are hidden to make the overall structure easier to read.]
````json
{
  "id": "00010000000000",
  "url": "/z/00010000000000",
  "id": "00001000000000",
  "url": "/z/00001000000000",
  "order": [
    {
      "id": "00001001000000",
      "url": "/z/00001001000000",
      "meta": {...}
    },
    {

id: 00001000000000
title: Zettelstore Manual
role: manual
tags: #manual #zettelstore
syntax: zmk

* [[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]]
* Troubleshooting
* Frequently asked questions

Licensed under the EUPL-1.2-or-later.

Zettelstore
===========

Zettelstore is a software that collects and relates your notes ("zettel") to
represent and enhance your knowledge. It helps with many tasks of personal
knowledge management by explicitly supporting the Zettelkasten method (see:
https://en.wikipedia.org/wiki/Zettelkasten). The method is based on creating
many individual notes, each with one idea or information, that are related to
each other. Since knowledge is typically build up gradually, one major focus is
a long-term store of these notes, hence the name "Zettelstore".

To get an impression, take a look at the manual at
https://zettelstore.de/manual/. It is a live example of the zettelstore
software, running in read-only mode. You can download it separately and it is
possible to make it directly available for your local Zettelstore.

The software, including the manual, is licensed under the European Union Public
License 1.2 (or later). See the separate file LICENSE.txt.

To get in contact with the developer, send an email to ds@zettelstore.de or
follow Zettelstore on Twitter: https://twitter.com/zettelstore.

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

// Package domain provides domain specific types, constants, and functions.
package domain

import (
	"unicode/utf8"
import "unicode/utf8"
)

// Content is just the uninterpreted content of a zettel.
type Content string

// NewContent creates a new content from a string.
func NewContent(s string) Content { return Content(s) }

	Invalid          = Zid(0) // Invalid is a Zid that will never be valid
	ConfigurationZid = Zid(100)

	// WebUI HTML templates are in the range 10000..19999
	BaseTemplateZid    = Zid(10100)
	LoginTemplateZid   = Zid(10200)
	ListTemplateZid    = Zid(10300)
	DetailTemplateZid  = Zid(10401)
	ZettelTemplateZid  = Zid(10401)
	InfoTemplateZid    = Zid(10402)
	FormTemplateZid    = Zid(10403)
	RenameTemplateZid  = Zid(10404)
	DeleteTemplateZid  = Zid(10405)
	ContextTemplateZid = Zid(10406)
	RolesTemplateZid   = Zid(10500)
	TagsTemplateZid    = Zid(10600)
	ErrorTemplateZid   = Zid(10700)

	// WebUI CSS pages are in the range 20000..29999
	BaseCSSZid = Zid(20001)

	// WebUI JS pages are in the range 30000..39999

	// Range 90000...99999 is reserved for zettel templates

	result := make(Set, c)
	for _, zid := range zids {
		result[zid] = true
	}
	return result
}

// Sort returns the set as a sorted slice of zettel identifier.
func (s Set) Sort() Slice {
// Sorted returns the set as a sorted slice of zettel identifier.
func (s Set) Sorted() Slice {
	if l := len(s); l > 0 {
		result := make(Slice, 0, l)
		for zid := range s {
			result = append(result, zid)
		}
		result.Sort()
		return result
	}
	return nil
}

// Intersect removes all zettel identifier that are not in the other set.
// Both sets can be modified by this method. One of them is the set returned.
// It contains the intersection of both.
func (s Set) Intersect(other Set) Set {
	if len(s) > len(other) {
		s, other = other, s
	}
	for zid, inSet := range s {
		if !inSet {
			delete(s, zid)
			continue
		}
		otherInSet, otherOk := other[zid]
		if !otherInSet || !otherOk {
			delete(s, zid)
		}
	}
	return s
}

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package id provides domain specific types, constants, and functions about
// zettel identifier.
package id_test

import (
	"testing"

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

func TestSetSorted(t *testing.T) {
	testcases := []struct {
		set id.Set
		exp id.Slice
	}{
		{nil, nil},
		{id.NewSet(), nil},
		{id.NewSet(9, 4, 6, 1, 7), id.Slice{1, 4, 6, 7, 9}},
	}
	for i, tc := range testcases {
		got := tc.set.Sorted()
		if !got.Equal(tc.exp) {
			t.Errorf("%d: %v.Sorted() should be %v, but got %v", i, tc.set, tc.exp, got)
		}
	}
}

func TestSetIntersection(t *testing.T) {
	testcases := []struct {
		s1, s2 id.Set
		exp    id.Slice
	}{
		{nil, nil, nil},
		{id.NewSet(), nil, nil},
		{id.NewSet(), id.NewSet(), nil},
		{id.NewSet(1), nil, nil},
		{id.NewSet(1), id.NewSet(), nil},
		{id.NewSet(1), id.NewSet(2), nil},
		{id.NewSet(1), id.NewSet(1), id.Slice{1}},
	}
	for i, tc := range testcases {
		sl1 := tc.s1.Sorted()
		sl2 := tc.s2.Sorted()
		got := tc.s1.Intersect(tc.s2).Sorted()
		if !got.Equal(tc.exp) {
			t.Errorf("%d: %v.Intersect(%v) should be %v, but got %v", i, sl1, sl2, tc.exp, got)
		}
		got = id.NewSet(sl2...).Intersect(id.NewSet(sl1...)).Sorted()
		if !got.Equal(tc.exp) {
			t.Errorf("%d: %v.Intersect(%v) should be %v, but got %v", i, sl2, sl1, tc.exp, got)
		}
	}
}

	if zs == nil {
		return nil
	}
	result := make(Slice, len(zs))
	copy(result, zs)
	return result
}

// Equal reports whether zs and other are the same length and contain the samle zettel
// identifier. A nil argument is equivalent to an empty slice.
func (zs Slice) Equal(other Slice) bool {
	if len(zs) != len(other) {
		return false
	}
	if len(zs) == 0 {
		return true
	}
	for i, e := range zs {
		if e != other[i] {
			return false
		}
	}
	return true
}

func (zs Slice) String() string {
	if len(zs) == 0 {
		return ""
	}
	var sb strings.Builder
	for i, zid := range zs {

import (
	"testing"

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

func TestSort(t *testing.T) {
func TestSliceSort(t *testing.T) {
	zs := id.Slice{9, 4, 6, 1, 7}
	zs.Sort()
	if zs[0] != 1 || zs[1] != 4 || zs[2] != 6 || zs[3] != 7 || zs[4] != 9 {
		t.Errorf("Slice.Sort did not work. Expected %v, got %v", id.Slice{1, 4, 6, 7, 9}, zs)
	exp := id.Slice{1, 4, 6, 7, 9}
	if !zs.Equal(exp) {
		t.Errorf("Slice.Sort did not work. Expected %v, got %v", exp, zs)
	}
}

func TestCopy(t *testing.T) {
	var orig id.Slice
	got := orig.Copy()
	if got != nil {
		t.Errorf("Nil copy resulted in %v", got)
	}
	orig = id.Slice{9, 4, 6, 1, 7}
	got = orig.Copy()
	if len(got) != len(orig) || got[0] != 9 || got[1] != 4 || got[2] != 6 || got[3] != 1 || got[4] != 7 {
	if !orig.Equal(got) {
		t.Errorf("Slice.Copy did not work. Expected %v, got %v", orig, got)
	}
}

func TestSliceEqual(t *testing.T) {
	testcases := []struct {
		s1, s2 id.Slice
		exp    bool
	}{
		{nil, nil, true},
		{nil, id.Slice{}, true},
		{nil, id.Slice{1}, false},
		{id.Slice{1}, id.Slice{1}, true},
		{id.Slice{1}, id.Slice{2}, false},
		{id.Slice{1, 2}, id.Slice{2, 1}, false},
		{id.Slice{1, 2}, id.Slice{1, 2}, true},
	}
	for i, tc := range testcases {
		got := tc.s1.Equal(tc.s2)
		if got != tc.exp {
			t.Errorf("%d/%v.Equal(%v)==%v, but got %v", i, tc.s1, tc.s2, tc.exp, got)
		}
		got = tc.s2.Equal(tc.s1)
		if got != tc.exp {
			t.Errorf("%d/%v.Equal(%v)==%v, but got %v", i, tc.s2, tc.s1, tc.exp, got)
		}
	}
}

func TestString(t *testing.T) {
func TestSliceString(t *testing.T) {
	testcases := []struct {
		in  id.Slice
		exp string
	}{
		{nil, ""},
		{id.Slice{}, ""},
		{id.Slice{1}, "00000000000001"},

	KeyForward           = registerKey("forward", TypeIDSet, usageProperty, "")
	KeyHomeZettel        = registerKey("home-zettel", TypeID, usageUser, "")
	KeyLang              = registerKey("lang", TypeWord, usageUser, "")
	KeyLicense           = registerKey("license", TypeEmpty, usageUser, "")
	KeyListPageSize      = registerKey("list-page-size", TypeNumber, usageUser, "")
	KeyMarkerExternal    = registerKey("marker-external", TypeEmpty, usageUser, "")
	KeyModified          = registerKey("modified", TypeTimestamp, usageComputed, "")
	KeyNoIndex           = registerKey("no-index", TypeBool, usageUser, "")
	KeyPrecursor         = registerKey("precursor", TypeIDSet, usageUser, KeyFolge)
	KeyPublished         = registerKey("published", TypeTimestamp, usageProperty, "")
	KeyReadOnly          = registerKey("read-only", TypeWord, usageUser, "")
	KeySiteName          = registerKey("site-name", TypeString, usageUser, "")
	KeyURL               = registerKey("url", TypeURL, usageUser, "")
	KeyUserID            = registerKey("user-id", TypeWord, usageUser, "")
	KeyUserRole          = registerKey("user-role", TypeWord, usageUser, "")

	"testing"

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

const testID = id.Zid(98765432101234)

func newMeta(title string, tags []string, syntax string) *Meta {
	m := New(testID)
	if title != "" {
		m.Set(KeyTitle, title)
	}
	if tags != nil {
		m.Set(KeyTags, strings.Join(tags, " "))
	}
	if syntax != "" {
		m.Set(KeySyntax, syntax)
	}
	return m
}

func TestKeyIsValid(t *testing.T) {
	validKeys := []string{"0", "a", "0-", "title", "title-----", strings.Repeat("r", 255)}
	for _, key := range validKeys {
		if !KeyIsValid(key) {
			t.Errorf("Key %q wrongly identified as invalid key", key)
		}
	}

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package encfun provides some helper function to work with encodings.
package encfun

import (
	"strings"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/parser"
)

// MetaAsInlineSlice returns the value of the given metadata key as an inlince slice.
func MetaAsInlineSlice(m *meta.Meta, key string) ast.InlineSlice {
	return parser.ParseMetadata(m.GetDefault(key, ""))
}

// MetaAsText returns the value of given metadata as text.
func MetaAsText(m *meta.Meta, key string) string {
	textEncoder := encoder.Create("text", nil)
	var sb strings.Builder
	_, err := textEncoder.WriteInlines(&sb, MetaAsInlineSlice(m, key))
	if err == nil {
		return sb.String()
	}
	return ""
}

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
)

// Encoder is an interface that allows to encode different parts of a zettel.
type Encoder interface {
	SetOption(Option)

	WriteZettel(io.Writer, *ast.ZettelNode, bool) (int, error)
	WriteMeta(io.Writer, *meta.Meta) (int, error)
	WriteContent(io.Writer, *ast.ZettelNode) (int, error)
	WriteBlocks(io.Writer, ast.BlockSlice) (int, error)
	WriteInlines(io.Writer, ast.InlineSlice) (int, error)
}

// Some errors to signal when encoder methods are not implemented.
var (
	ErrNoWriteZettel  = errors.New("method WriteZettel is not implemented")
	ErrNoWriteMeta    = errors.New("method WriteMeta is not implemented")
	ErrNoWriteContent = errors.New("method WriteContent is not implemented")
	ErrNoWriteBlocks  = errors.New("method WriteBlocks is not implemented")
	ErrNoWriteInlines = errors.New("method WriteInlines is not implemented")
)

// Option allows to configure an encoder
type Option interface {
	Name() string
}

// Create builds a new encoder with the given options.
func Create(format string, options ...Option) Encoder {
func Create(format string, env *Environment) Encoder {
	if info, ok := registry[format]; ok {
		enc := info.Create()
		for _, opt := range options {
			enc.SetOption(opt)
		}
		return enc
		return info.Create(env)
	}
	return nil
}

// Info stores some data about an encoder.
type Info struct {
	Create  func() Encoder
	Create  func(*Environment) Encoder
	Default bool
}

var registry = map[string]Info{}
var defFormat string

// Register the encoder for later retrieval.

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package encoder provides a generic interface to encode the abstract syntax
// tree into some text form.
package encoder

import "zettelstore.de/z/ast"

// Environment specifies all data and functions that affects encoding.
type Environment struct {
	// Important for many encoder.
	LinkAdapter  func(*ast.LinkNode) ast.InlineNode
	ImageAdapter func(*ast.ImageNode) ast.InlineNode
	CiteAdapter  func(*ast.CiteNode) ast.InlineNode

	// Important for HTML encoder
	Lang           string // default language
	Interactive    bool   // Encoded data will be placed in interactive content
	Xhtml          bool   // use XHTML syntax instead of HTML syntax
	MarkerExternal string // Marker after link to (external) material.
	NewWindow      bool   // open link in new window
	IgnoreMeta     map[string]bool
	footnotes      []*ast.FootnoteNode // Stores footnotes detected while encoding
}

// AdaptLink helps to call the link adapter.
func (env *Environment) AdaptLink(ln *ast.LinkNode) (*ast.LinkNode, ast.InlineNode) {
	if env == nil || env.LinkAdapter == nil {
		return ln, nil
	}
	n := env.LinkAdapter(ln)
	if n == nil {
		return ln, nil
	}
	if ln2, ok := n.(*ast.LinkNode); ok {
		return ln2, nil
	}
	return nil, n
}

// AdaptImage helps to call the link adapter.
func (env *Environment) AdaptImage(in *ast.ImageNode) (*ast.ImageNode, ast.InlineNode) {
	if env == nil || env.ImageAdapter == nil {
		return in, nil
	}
	n := env.ImageAdapter(in)
	if n == nil {
		return in, nil
	}
	if in2, ok := n.(*ast.ImageNode); ok {
		return in2, nil
	}
	return nil, n
}

// AdaptCite helps to call the link adapter.
func (env *Environment) AdaptCite(cn *ast.CiteNode) (*ast.CiteNode, ast.InlineNode) {
	if env == nil || env.CiteAdapter == nil {
		return cn, nil
	}
	n := env.CiteAdapter(cn)
	if n == nil {
		return cn, nil
	}
	if cn2, ok := n.(*ast.CiteNode); ok {
		return cn2, nil
	}
	return nil, n
}

// IsInteractive returns true, if Interactive is enabled and currently embedded
// interactive encoding will take place.
func (env *Environment) IsInteractive(inInteractive bool) bool {
	return inInteractive && env != nil && env.Interactive
}

// IsXHTML return true, if XHTML is enabled.
func (env *Environment) IsXHTML() bool {
	return env != nil && env.Xhtml
}

// HasNewWindow retruns true, if a new browser windows should be opened.
func (env *Environment) HasNewWindow() bool {
	return env != nil && env.NewWindow
}

// AddFootnote adds a footnote node to the environment and returns the number of that footnote.
func (env *Environment) AddFootnote(fn *ast.FootnoteNode) int {
	if env == nil {
		return 0
	}
	env.footnotes = append(env.footnotes, fn)
	return len(env.footnotes)
}

// GetCleanFootnotes returns the list of remembered footnote and forgets about them.
func (env *Environment) GetCleanFootnotes() []*ast.FootnoteNode {
	if env == nil {
		return nil
	}
	result := env.footnotes
	env.footnotes = nil
	return result
}

	v.b.WriteStrings("</h", strLvl, ">\n")
}

// VisitHRule writes HTML code for a horizontal rule: <hr>.
func (v *visitor) VisitHRule(hn *ast.HRuleNode) {
	v.b.WriteString("<hr")
	v.visitAttributes(hn.Attrs)
	if v.xhtml {
	if v.env.IsXHTML() {
		v.b.WriteString(" />\n")
	} else {
		v.b.WriteString(">\n")
	}
}

var listCode = map[ast.NestedListCode]string{

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

// Package htmlenc encodes the abstract syntax tree into HTML5.
package htmlenc

import (
	"fmt"
	"io"
	"strings"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/encoder/encfun"
	"zettelstore.de/z/parser"
)

func init() {
	encoder.Register("html", encoder.Info{
		Create: func() encoder.Encoder { return &htmlEncoder{} },
		Create: func(env *encoder.Environment) encoder.Encoder { return &htmlEncoder{env: env} },
	})
}

type htmlEncoder struct {
	lang           string // default language
	xhtml          bool   // use XHTML syntax instead of HTML syntax
	markerExternal string // Marker after link to (external) material.
	newWindow      bool   // open link in new window
	adaptLink      func(*ast.LinkNode) ast.InlineNode
	adaptImage     func(*ast.ImageNode) ast.InlineNode
	adaptCite      func(*ast.CiteNode) ast.InlineNode
	ignoreMeta     map[string]bool
	footnotes      []*ast.FootnoteNode
}

func (he *htmlEncoder) SetOption(option encoder.Option) {
	switch opt := option.(type) {
	case *encoder.StringOption:
		switch opt.Key {
		case "lang":
			he.lang = opt.Value
		case meta.KeyMarkerExternal:
			he.markerExternal = opt.Value
		}
	case *encoder.BoolOption:
	env *encoder.Environment
		switch opt.Key {
		case "newwindow":
			he.newWindow = opt.Value
		case "xhtml":
			he.xhtml = opt.Value
		}
}
	case *encoder.StringsOption:
		if opt.Key == "no-meta" {
			he.ignoreMeta = make(map[string]bool, len(opt.Value))
			for _, v := range opt.Value {
				he.ignoreMeta[v] = true
			}

		}
	case *encoder.AdaptLinkOption:
		he.adaptLink = opt.Adapter
	case *encoder.AdaptImageOption:
		he.adaptImage = opt.Adapter
	case *encoder.AdaptCiteOption:
		he.adaptCite = opt.Adapter
	default:
		var name string
		if option != nil {
			name = option.Name()
		}
		fmt.Println("HESO", option, name)
	}
}

// WriteZettel encodes a full zettel as HTML5.
func (he *htmlEncoder) WriteZettel(
func (he *htmlEncoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	v := newVisitor(he, w)
	if !he.xhtml {
	if !he.env.IsXHTML() {
		v.b.WriteString("<!DOCTYPE html>\n")
	}
	if env := he.env; env != nil && env.Lang == "" {
	v.b.WriteStrings("<html lang=\"", he.lang, "\">\n<head>\n<meta charset=\"utf-8\">\n")
	textEnc := encoder.Create("text")
	var sb strings.Builder
	textEnc.WriteInlines(&sb, zn.Title)
	v.b.WriteStrings("<title>", sb.String(), "</title>")
		v.b.WriteStrings("<html>\n<head>")
	} else {
		v.b.WriteStrings("<html lang=\"", env.Lang, "\">")
	}
	v.b.WriteString("\n<head>\n<meta charset=\"utf-8\">\n")
	v.b.WriteStrings("<title>", encfun.MetaAsText(zn.InhMeta, meta.KeyTitle), "</title>")
	if inhMeta {
		v.acceptMeta(zn.InhMeta, false)
		v.acceptMeta(zn.InhMeta)
	} else {
		v.acceptMeta(zn.Zettel.Meta, false)
		v.acceptMeta(zn.Meta)
	}
	v.b.WriteString("\n</head>\n<body>\n")
	v.acceptBlockSlice(zn.Ast)
	v.writeEndnotes()
	v.b.WriteString("</body>\n</html>")
	length, err := v.b.Flush()
	return length, err
}

// WriteMeta encodes meta data as HTML5.
func (he *htmlEncoder) WriteMeta(w io.Writer, m *meta.Meta) (int, error) {
	v := newVisitor(he, w)

	// Write title
	if title, ok := m.Get(meta.KeyTitle); ok {
		textEnc := encoder.Create("text", nil)
		var sb strings.Builder
		textEnc.WriteInlines(&sb, parser.ParseMetadata(title))
		v.b.WriteStrings("<meta name=\"zs-", meta.KeyTitle, "\" content=\"")
		v.writeQuotedEscaped(sb.String())
		v.b.WriteString("\">")
	}

	// Write other metadata
	v.acceptMeta(m, true)
	v.acceptMeta(m)
	length, err := v.b.Flush()
	return length, err
}

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

// WriteBlocks encodes a block slice.
func (he *htmlEncoder) WriteBlocks(w io.Writer, bs ast.BlockSlice) (int, error) {
	v := newVisitor(he, w)
	v.acceptBlockSlice(bs)
	v.writeEndnotes()
	length, err := v.b.Flush()
	return length, err
}

// WriteInlines writes an inline slice to the writer
func (he *htmlEncoder) WriteInlines(w io.Writer, is ast.InlineSlice) (int, error) {
	v := newVisitor(he, w)
	if env := he.env; env != nil {
		v.inInteractive = env.Interactive
	}
	v.acceptInlineSlice(is)
	length, err := v.b.Flush()
	return length, err
}

	v.b.WriteString("<span class=\"zettel-tag\">#")
	v.writeHTMLEscaped(tn.Tag)
	v.b.WriteString("</span>")
}

// VisitSpace emits a white space.
func (v *visitor) VisitSpace(sn *ast.SpaceNode) {
	if v.inVerse || v.xhtml {
	if v.inVerse || v.env.IsXHTML() {
		v.b.WriteString(sn.Lexeme)
	} else {
		v.b.WriteByte(' ')
	}
}

// VisitBreak writes HTML code for line breaks.
func (v *visitor) VisitBreak(bn *ast.BreakNode) {
	if bn.Hard {
		if v.xhtml {
		if v.env.IsXHTML() {
			v.b.WriteString("<br />\n")
		} else {
			v.b.WriteString("<br>\n")
		}
	} else {
		v.b.WriteByte('\n')
	}
}

// VisitLink writes HTML code for links.
func (v *visitor) VisitLink(ln *ast.LinkNode) {
	if adapt := v.enc.adaptLink; adapt != nil {
		n := adapt(ln)
	ln, n := v.env.AdaptLink(ln)
	if n != nil {
		var ok bool
		if ln, ok = n.(*ast.LinkNode); !ok {
			n.Accept(v)
			return
		n.Accept(v)
		return
		}
	}
	v.lang.push(ln.Attrs)
	defer v.lang.pop()

	switch ln.Ref.State {
	case ast.RefStateSelf, ast.RefStateFound, ast.RefStateHosted, ast.RefStateBased:
		v.writeAHref(ln.Ref, ln.Attrs, ln.Inlines)
	case ast.RefStateBroken:
		attrs := ln.Attrs.Clone()
		attrs = attrs.Set("class", "zs-broken")
		attrs = attrs.Set("title", "Zettel not found") // l10n
		v.writeAHref(ln.Ref, attrs, ln.Inlines)
	case ast.RefStateExternal:
		attrs := ln.Attrs.Clone()
		attrs = attrs.Set("class", "zs-external")
		if v.enc.newWindow {
		if v.env.HasNewWindow() {
			attrs = attrs.Set("target", "_blank").Set("rel", "noopener noreferrer")
		}
		v.writeAHref(ln.Ref, attrs, ln.Inlines)
		if v.env != nil {
		v.b.WriteString(v.enc.markerExternal)
			v.b.WriteString(v.env.MarkerExternal)
		}
	default:
		if v.env.IsInteractive(v.inInteractive) {
			v.writeSpan(ln.Inlines, ln.Attrs)
			return
		}
		v.b.WriteString("<a href=\"")
		v.writeQuotedEscaped(ln.Ref.Value)
		v.b.WriteByte('"')
		v.visitAttributes(ln.Attrs)
		v.b.WriteByte('>')
		v.inInteractive = true
		v.acceptInlineSlice(ln.Inlines)
		v.inInteractive = false
		v.b.WriteString("</a>")
	}
}

func (v *visitor) writeAHref(ref *ast.Reference, attrs *ast.Attributes, ins ast.InlineSlice) {
	if v.env.IsInteractive(v.inInteractive) {
		v.writeSpan(ins, attrs)
		return
	}
	v.b.WriteString("<a href=\"")
	v.writeReference(ref)
	v.b.WriteByte('"')
	v.visitAttributes(attrs)
	v.b.WriteByte('>')
	v.inInteractive = true
	v.acceptInlineSlice(ins)
	v.inInteractive = false
	v.b.WriteString("</a>")
}

// VisitImage writes HTML code for images.
func (v *visitor) VisitImage(in *ast.ImageNode) {
	if adapt := v.enc.adaptImage; adapt != nil {
		n := adapt(in)
	in, n := v.env.AdaptImage(in)
	if n != nil {
		var ok bool
		if in, ok = n.(*ast.ImageNode); !ok {
			n.Accept(v)
			return
		}
		n.Accept(v)
		return
	}
	}

	v.lang.push(in.Attrs)
	defer v.lang.pop()

	if in.Ref == nil {
		v.b.WriteString("<img src=\"data:image/")
		switch in.Syntax {
		case "svg":

		v.b.WriteString("<img src=\"")
		v.writeReference(in.Ref)
	}
	v.b.WriteString("\" alt=\"")
	v.acceptInlineSlice(in.Inlines)
	v.b.WriteByte('"')
	v.visitAttributes(in.Attrs)
	if v.xhtml {
	if v.env.IsXHTML() {
		v.b.WriteString(" />")
	} else {
		v.b.WriteByte('>')
	}
}

// VisitCite writes code for citations.
func (v *visitor) VisitCite(cn *ast.CiteNode) {
	if adapt := v.enc.adaptCite; adapt != nil {
		n := adapt(cn)
		if n != cn {
			n.Accept(v)
			return
		}
	cn, n := v.env.AdaptCite(cn)
	if n != nil {
		n.Accept(v)
		return
	}
	if cn == nil {
		return
	}

	v.lang.push(cn.Attrs)
	defer v.lang.pop()

	if cn != nil {
		v.b.WriteString(cn.Key)
		if len(cn.Inlines) > 0 {
			v.b.WriteString(", ")
			v.acceptInlineSlice(cn.Inlines)
	v.b.WriteString(cn.Key)
	if len(cn.Inlines) > 0 {
		v.b.WriteString(", ")
		v.acceptInlineSlice(cn.Inlines)
		}
	}
}

// VisitFootnote write HTML code for a footnote.
func (v *visitor) VisitFootnote(fn *ast.FootnoteNode) {
	v.lang.push(fn.Attrs)
	defer v.lang.pop()
	if v.env.IsInteractive(v.inInteractive) {
		return

	v.enc.footnotes = append(v.enc.footnotes, fn)
	n := strconv.Itoa(len(v.enc.footnotes))
	}

	n := strconv.Itoa(v.env.AddFootnote(fn))
	v.b.WriteStrings("<sup id=\"fnref:", n, "\"><a href=\"#fn:", n, "\" class=\"zs-footnote-ref\" role=\"doc-noteref\">", n, "</a></sup>")
	// TODO: what to do with Attrs?
}

// VisitMark writes HTML code to mark a position.
func (v *visitor) VisitMark(mn *ast.MarkNode) {
	if v.env.IsInteractive(v.inInteractive) {
		return
	}
	if len(mn.Text) > 0 {
		v.b.WriteStrings("<a id=\"", mn.Text, "\"></a>")
	}
}

// VisitFormat write HTML code for formatting text.
func (v *visitor) VisitFormat(fn *ast.FormatNode) {

	case ast.FormatSub:
		code = "sub"
	case ast.FormatQuotation:
		code = "q"
	case ast.FormatSmall:
		code = "small"
	case ast.FormatSpan:
		code = "span"
		attrs = processSpanAttributes(attrs)
		v.writeSpan(fn.Inlines, processSpanAttributes(attrs))
		return
	case ast.FormatMonospace:
		code = "span"
		attrs = attrs.Set("style", "font-family:monospace")
	case ast.FormatQuote:
		v.visitQuotes(fn)
		return
	default:
		panic(fmt.Sprintf("Unknown format code %v", fn.Code))
	}
	v.b.WriteStrings("<", code)
	v.visitAttributes(attrs)
	v.b.WriteByte('>')
	v.acceptInlineSlice(fn.Inlines)
	v.b.WriteStrings("</", code, ">")
}

func (v *visitor) writeSpan(ins ast.InlineSlice, attrs *ast.Attributes) {
	v.b.WriteString("<span")
	v.visitAttributes(attrs)
	v.b.WriteByte('>')
	v.acceptInlineSlice(ins)
	v.b.WriteString("</span>")

}

var langQuotes = map[string][2]string{
	"en": {"&ldquo;", "&rdquo;"},
	"de": {"&bdquo;", "&ldquo;"},
	"fr": {"&laquo;&nbsp;", "&nbsp;&raquo;"},
}

	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/strfun"
)

// visitor writes the abstract syntax tree to an io.Writer.
type visitor struct {
	enc          *htmlEncoder
	b            encoder.BufWriter
	visibleSpace bool // Show space character in raw text
	inVerse      bool // In verse block
	xhtml        bool // copied from enc.xhtml
	lang         langStack
	env           *encoder.Environment
	b             encoder.BufWriter
	visibleSpace  bool // Show space character in raw text
	inVerse       bool // In verse block
	inInteractive bool // Rendered interactive HTML code
	lang          langStack
}

func newVisitor(he *htmlEncoder, w io.Writer) *visitor {
	var lang string
	if he.env != nil {
		lang = he.env.Lang
	}
	return &visitor{
		enc:   he,
		b:     encoder.NewBufWriter(w),
		env:  he.env,
		b:    encoder.NewBufWriter(w),
		xhtml: he.xhtml,
		lang:  newLangStack(he.lang),
		lang: newLangStack(lang),
	}
}

var mapMetaKey = map[string]string{
	meta.KeyCopyright: "copyright",
	meta.KeyLicense:   "license",
}

func (v *visitor) acceptMeta(m *meta.Meta, withTitle bool) {
	for i, pair := range m.Pairs(true) {
		if v.enc.ignoreMeta[pair.Key] {
func (v *visitor) acceptMeta(m *meta.Meta) {
	for _, pair := range m.Pairs(true) {
		if env := v.env; env != nil && env.IgnoreMeta[pair.Key] {
			continue
		}
		if i == 0 { // "title" is number 0...
			if withTitle {
		if pair.Key == meta.KeyTitle {
				// TODO: title value may contain zmk elements
				v.b.WriteStrings("<meta name=\"zs-", pair.Key, "\" content=\"")
				v.writeQuotedEscaped(pair.Value)
				v.b.WriteString("\">")
			}
			continue
		}
		if pair.Key == meta.KeyTags {
			v.writeTags(pair.Value)
		} else if key, ok := mapMetaKey[pair.Key]; ok {
			v.writeMeta("", key, pair.Value)
		} else {

func (v *visitor) acceptInlineSlice(ins ast.InlineSlice) {
	for _, in := range ins {
		in.Accept(v)
	}
}

func (v *visitor) writeEndnotes() {
	footnotes := v.env.GetCleanFootnotes()
	if len(v.enc.footnotes) > 0 {
	if len(footnotes) > 0 {
		v.b.WriteString("<ol class=\"zs-endnotes\">\n")
		for i := 0; i < len(v.enc.footnotes); i++ {
		for i := 0; i < len(footnotes); i++ {
			// Do not use a range loop above, because a footnote may contain
			// a footnote. Therefore v.enc.footnote may grow during the loop.
			fn := v.enc.footnotes[i]
			fn := footnotes[i]
			n := strconv.Itoa(i + 1)
			v.b.WriteStrings("<li id=\"fn:", n, "\" role=\"doc-endnote\">")
			v.acceptInlineSlice(fn.Inlines)
			v.b.WriteStrings(
				" <a href=\"#fnref:",
				n,
				"\" class=\"zs-footnote-backref\" role=\"doc-backlink\">&#x21a9;&#xfe0e;</a></li>\n")

	"io"
	"sort"
	"strconv"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/encoder/encfun"
)

func init() {
	encoder.Register("djson", encoder.Info{
		Create: func() encoder.Encoder { return &jsonDetailEncoder{} },
		Create: func(env *encoder.Environment) encoder.Encoder { return &jsonDetailEncoder{env: env} },
	})
}

type jsonDetailEncoder struct {
	adaptLink  func(*ast.LinkNode) ast.InlineNode
	adaptImage func(*ast.ImageNode) ast.InlineNode
	title      ast.InlineSlice
}

// SetOption sets an option for the encoder
func (je *jsonDetailEncoder) SetOption(option encoder.Option) {
	switch opt := option.(type) {
	case *encoder.TitleOption:
	env *encoder.Environment
		je.title = opt.Inline
	case *encoder.AdaptLinkOption:
		je.adaptLink = opt.Adapter
	case *encoder.AdaptImageOption:
		je.adaptImage = opt.Adapter
	}
}

// WriteZettel writes the encoded zettel to the writer.
func (je *jsonDetailEncoder) WriteZettel(
func (je *jsonDetailEncoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	v := newDetailVisitor(w, je)
	v.b.WriteString("{\"meta\":{\"title\":")
	v.acceptInlineSlice(zn.Title)
	v.acceptInlineSlice(encfun.MetaAsInlineSlice(zn.InhMeta, meta.KeyTitle))
	if inhMeta {
		v.writeMeta(zn.InhMeta, false)
		v.writeMeta(zn.InhMeta)
	} else {
		v.writeMeta(zn.Zettel.Meta, false)
		v.writeMeta(zn.Meta)
	}
	v.b.WriteByte('}')
	v.b.WriteString(",\"content\":")
	v.acceptBlockSlice(zn.Ast)
	v.b.WriteByte('}')
	length, err := v.b.Flush()
	return length, err
}

// WriteMeta encodes meta data as JSON.
func (je *jsonDetailEncoder) WriteMeta(w io.Writer, m *meta.Meta) (int, error) {
	v := newDetailVisitor(w, je)
	v.b.WriteByte('{')
	if je.title == nil {
		v.writeMeta(m, true)
	} else {
		v.b.WriteString("\"title\":")
		v.acceptInlineSlice(je.title)
		v.writeMeta(m, false)
	v.b.WriteString("{\"title\":")
	v.acceptInlineSlice(encfun.MetaAsInlineSlice(m, meta.KeyTitle))
	v.writeMeta(m)
	}
	v.b.WriteByte('}')
	length, err := v.b.Flush()
	return length, err
}

func (je *jsonDetailEncoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	return je.WriteBlocks(w, zn.Ast)

	length, err := v.b.Flush()
	return length, err
}

// detailVisitor writes the abstract syntax tree to an io.Writer.
type detailVisitor struct {
	b   encoder.BufWriter
	enc *jsonDetailEncoder
	env *encoder.Environment
}

func newDetailVisitor(w io.Writer, je *jsonDetailEncoder) *detailVisitor {
	return &detailVisitor{b: encoder.NewBufWriter(w), enc: je}
	return &detailVisitor{b: encoder.NewBufWriter(w), env: je.env}
}

// VisitPara emits JSON code for a paragraph.
func (v *detailVisitor) VisitPara(pn *ast.ParaNode) {
	v.writeNodeStart("Para")
	v.writeContentStart('i')
	v.acceptInlineSlice(pn.Inlines)

	ast.RefStateHosted:   "local",
	ast.RefStateBased:    "based",
	ast.RefStateExternal: "external",
}

// VisitLink writes JSON code for links.
func (v *detailVisitor) VisitLink(ln *ast.LinkNode) {
	if adapt := v.enc.adaptLink; adapt != nil {
		n := adapt(ln)
	ln, n := v.env.AdaptLink(ln)
	if n != nil {
		var ok bool
		if ln, ok = n.(*ast.LinkNode); !ok {
			n.Accept(v)
			return
		n.Accept(v)
		return
		}
	}
	v.writeNodeStart("Link")
	v.visitAttributes(ln.Attrs)
	v.writeContentStart('q')
	writeEscaped(&v.b, mapRefState[ln.Ref.State])
	v.writeContentStart('s')
	writeEscaped(&v.b, ln.Ref.String())
	v.writeContentStart('i')
	v.acceptInlineSlice(ln.Inlines)
	v.b.WriteByte('}')
}

// VisitImage writes JSON code for images.
func (v *detailVisitor) VisitImage(in *ast.ImageNode) {
	if adapt := v.enc.adaptImage; adapt != nil {
		n := adapt(in)
	in, n := v.env.AdaptImage(in)
	if n != nil {
		var ok bool
		if in, ok = n.(*ast.ImageNode); !ok {
			n.Accept(v)
			return
		n.Accept(v)
		return
		}
	}
	v.writeNodeStart("Image")
	v.visitAttributes(in.Attrs)
	if in.Ref == nil {
		v.writeContentStart('j')
		v.b.WriteString("\"s\":")
		writeEscaped(&v.b, in.Syntax)

	if b, ok := contentCode[code]; ok {
		v.b.Write(b)
		return
	}
	panic("Unknown content code " + strconv.Itoa(int(code)))
}

func (v *detailVisitor) writeMeta(m *meta.Meta, withTitle bool) {
func (v *detailVisitor) writeMeta(m *meta.Meta) {
	first := withTitle
	for _, p := range m.Pairs(true) {
		if p.Key == "title" && !withTitle {
		if p.Key == meta.KeyTitle {
			continue
		}
		if first {
			v.b.WriteByte('"')
			first = false
		} else {
			v.b.WriteString(",\"")
		v.b.WriteString(",\"")
		}
		v.b.Write(Escape(p.Key))
		v.b.WriteString("\":")
		if m.Type(p.Key).IsSet {
			v.writeSetValue(p.Value)
		} else {
			v.b.WriteByte('"')
			v.b.Write(Escape(p.Value))

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

func init() {
	encoder.Register("json", encoder.Info{
		Create:  func() encoder.Encoder { return &jsonEncoder{} },
		Create:  func(*encoder.Environment) encoder.Encoder { return &jsonEncoder{} },
		Default: true,
	})
}

// jsonEncoder is just a stub. It is not implemented. The real implementation
// is in file web/adapter/json.go
type jsonEncoder struct{}

// SetOption does nothing because this encoder does not recognize any option.
func (je *jsonEncoder) SetOption(option encoder.Option) {}

// WriteZettel writes the encoded zettel to the writer.
func (je *jsonEncoder) WriteZettel(
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	return 0, encoder.ErrNoWriteZettel
}

// WriteMeta encodes meta data as HTML5.

	"io"
	"sort"
	"strconv"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/encoder/encfun"
	"zettelstore.de/z/parser"
)

func init() {
	encoder.Register("native", encoder.Info{
		Create: func() encoder.Encoder { return &nativeEncoder{} },
		Create: func(env *encoder.Environment) encoder.Encoder { return &nativeEncoder{env: env} },
	})
}

type nativeEncoder struct {
	adaptLink  func(*ast.LinkNode) ast.InlineNode
	adaptImage func(*ast.ImageNode) ast.InlineNode
}

// SetOption sets one option for this encoder.
func (ne *nativeEncoder) SetOption(option encoder.Option) {
	switch opt := option.(type) {
	case *encoder.AdaptLinkOption:
	env *encoder.Environment
		ne.adaptLink = opt.Adapter
	case *encoder.AdaptImageOption:
		ne.adaptImage = opt.Adapter
	}
}

// WriteZettel encodes the zettel to the writer.
func (ne *nativeEncoder) WriteZettel(
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	v := newVisitor(w, ne)
	v.b.WriteString("[Title ")
	v.acceptInlineSlice(zn.Title)
	v.acceptInlineSlice(encfun.MetaAsInlineSlice(zn.InhMeta, meta.KeyTitle))
	v.b.WriteByte(']')
	if inhMeta {
		v.acceptMeta(zn.InhMeta, false)
	} else {
		v.acceptMeta(zn.Zettel.Meta, false)
		v.acceptMeta(zn.Meta, false)
	}
	v.b.WriteByte('\n')
	v.acceptBlockSlice(zn.Ast)
	length, err := v.b.Flush()
	return length, err
}

// WriteMeta encodes meta data as HTML5.
// WriteMeta encodes meta data in native format.
func (ne *nativeEncoder) WriteMeta(w io.Writer, m *meta.Meta) (int, error) {
	v := newVisitor(w, ne)
	v.acceptMeta(m, true)
	length, err := v.b.Flush()
	return length, err
}

	return length, err
}

// visitor writes the abstract syntax tree to an io.Writer.
type visitor struct {
	b     encoder.BufWriter
	level int
	enc   *nativeEncoder
	env   *encoder.Environment
}

func newVisitor(w io.Writer, enc *nativeEncoder) *visitor {
	return &visitor{b: encoder.NewBufWriter(w), enc: enc}
	return &visitor{b: encoder.NewBufWriter(w), env: enc.env}
}

var (
	rawBackslash   = []byte{'\\', '\\'}
	rawDoubleQuote = []byte{'\\', '"'}
	rawNewline     = []byte{'\\', 'n'}
)

func (v *visitor) acceptMeta(m *meta.Meta, withTitle bool) {
	if withTitle {
		v.b.WriteString("[Title \"")
		v.writeEscaped(m.GetDefault(meta.KeyTitle, ""))
		v.b.WriteString("\"]")
		v.b.WriteString("[Title ")
		v.acceptInlineSlice(parser.ParseMetadata(m.GetDefault(meta.KeyTitle, "")))
		v.b.WriteByte(']')
	}
	v.writeMetaString(m, meta.KeyRole, "Role")
	v.writeMetaList(m, meta.KeyTags, "Tags")
	v.writeMetaString(m, meta.KeySyntax, "Syntax")
	if pairs := m.PairsRest(true); len(pairs) > 0 {
		v.b.WriteString("\n[Header")
	pairs := m.PairsRest(true)
	if len(pairs) == 0 {
		return
	}
	v.b.WriteString("\n[Header")
		first := true
		v.level++
		for _, p := range pairs {
			if !first {
				v.b.WriteByte(',')
			}
			v.writeNewLine()
			v.b.WriteByte('[')
			v.b.WriteStrings(p.Key, " \"")
			v.writeEscaped(p.Value)
			v.b.WriteString("\"]")
	v.level++
	for i, p := range pairs {
		if i > 0 {
			v.b.WriteByte(',')
		}
		v.writeNewLine()
		v.b.WriteByte('[')
		v.b.WriteStrings(p.Key, " \"")
		v.writeEscaped(p.Value)
		v.b.WriteString("\"]")
			first = false
		}
		v.level--
		v.b.WriteByte(']')
	}
	v.level--
	v.b.WriteByte(']')
	}
}

func (v *visitor) writeMetaString(m *meta.Meta, key, native string) {
	if val, ok := m.Get(key); ok && len(val) > 0 {
		v.b.WriteStrings("\n[", native, " \"", val, "\"]")
	}
}

	ast.RefStateHosted:   "LOCAL",
	ast.RefStateBased:    "BASED",
	ast.RefStateExternal: "EXTERNAL",
}

// VisitLink writes native code for links.
func (v *visitor) VisitLink(ln *ast.LinkNode) {
	if adapt := v.enc.adaptLink; adapt != nil {
		n := adapt(ln)
	ln, n := v.env.AdaptLink(ln)
	if n != nil {
		var ok bool
		if ln, ok = n.(*ast.LinkNode); !ok {
			n.Accept(v)
			return
		n.Accept(v)
		return
		}
	}
	v.b.WriteString("Link")
	v.visitAttributes(ln.Attrs)
	v.b.WriteByte(' ')
	v.b.WriteString(mapRefState[ln.Ref.State])
	v.b.WriteString(" \"")
	v.writeEscaped(ln.Ref.String())
	v.b.WriteString("\" [")
	if !ln.OnlyRef {
		v.acceptInlineSlice(ln.Inlines)
	}
	v.b.WriteByte(']')
}

// VisitImage writes native code for images.
func (v *visitor) VisitImage(in *ast.ImageNode) {
	if adapt := v.enc.adaptImage; adapt != nil {
		n := adapt(in)
	in, n := v.env.AdaptImage(in)
	if n != nil {
		var ok bool
		if in, ok = n.(*ast.ImageNode); !ok {
			n.Accept(v)
			return
		n.Accept(v)
		return
		}
	}
	v.b.WriteString("Image")
	v.visitAttributes(in.Attrs)
	if in.Ref == nil {
		v.b.WriteStrings(" {\"", in.Syntax, "\" \"")
		switch in.Syntax {
		case "svg":

//-----------------------------------------------------------------------------
// Copyright (c) 2020 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.
//-----------------------------------------------------------------------------

// Package encoder provides a generic interface to encode the abstract syntax
// tree into some text form.
package encoder

import (
	"zettelstore.de/z/ast"
)

// StringOption is an option with a string value
type StringOption struct {
	Key   string
	Value string
}

// Name returns the visible name of this option.
func (so *StringOption) Name() string { return so.Key }

// BoolOption is an option with a boolean value.
type BoolOption struct {
	Key   string
	Value bool
}

// Name returns the visible name of this option.
func (bo *BoolOption) Name() string { return bo.Key }

// TitleOption is an option to give the title as a AST inline slice
type TitleOption struct {
	Inline ast.InlineSlice
}

// Name returns the visible name of this option.
func (mo *TitleOption) Name() string { return "title" }

// StringsOption is an option that have a sequence of strings as the value.
type StringsOption struct {
	Key   string
	Value []string
}

// Name returns the visible name of this option.
func (so *StringsOption) Name() string { return so.Key }

// AdaptLinkOption specifies a link adapter.
type AdaptLinkOption struct {
	Adapter func(*ast.LinkNode) ast.InlineNode
}

// Name returns the visible name of this option.
func (al *AdaptLinkOption) Name() string { return "AdaptLinkOption" }

// AdaptImageOption specifies an image adapter.
type AdaptImageOption struct {
	Adapter func(*ast.ImageNode) ast.InlineNode
}

// Name returns the visible name of this option.
func (al *AdaptImageOption) Name() string { return "AdaptImageOption" }

// AdaptCiteOption specifies a citation adapter.
type AdaptCiteOption struct {
	Adapter func(*ast.CiteNode) ast.InlineNode
}

// Name returns the visible name of this option.
func (al *AdaptCiteOption) Name() string { return "AdaptCiteOption" }

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

func init() {
	encoder.Register("raw", encoder.Info{
		Create: func() encoder.Encoder { return &rawEncoder{} },
		Create: func(*encoder.Environment) encoder.Encoder { return &rawEncoder{} },
	})
}

type rawEncoder struct{}

// SetOption does nothing because this encoder does not recognize any option.
func (re *rawEncoder) SetOption(option encoder.Option) {}

// WriteZettel writes the encoded zettel to the writer.
func (re *rawEncoder) WriteZettel(
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	b := encoder.NewBufWriter(w)
	if inhMeta {
		zn.InhMeta.Write(&b, true)
	} else {
		zn.Zettel.Meta.Write(&b, true)
		zn.Meta.Write(&b, true)
	}
	b.WriteByte('\n')
	b.WriteString(zn.Zettel.Content.AsString())
	b.WriteString(zn.Content.AsString())
	length, err := b.Flush()
	return length, err
}

// WriteMeta encodes meta data as HTML5.
func (re *rawEncoder) WriteMeta(w io.Writer, m *meta.Meta) (int, error) {
	b := encoder.NewBufWriter(w)
	m.Write(&b, true)
	length, err := b.Flush()
	return length, err
}

func (re *rawEncoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {
	b := encoder.NewBufWriter(w)
	b.WriteString(zn.Zettel.Content.AsString())
	b.WriteString(zn.Content.AsString())
	length, err := b.Flush()
	return length, err
}

// WriteBlocks writes a block slice to the writer
func (re *rawEncoder) WriteBlocks(w io.Writer, bs ast.BlockSlice) (int, error) {
	return 0, encoder.ErrNoWriteBlocks
}

// WriteInlines writes an inline slice to the writer
func (re *rawEncoder) WriteInlines(w io.Writer, is ast.InlineSlice) (int, error) {
	return 0, encoder.ErrNoWriteInlines
}

import (
	"io"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/parser"
)

func init() {
	encoder.Register("text", encoder.Info{
		Create: func() encoder.Encoder { return &textEncoder{} },
		Create: func(*encoder.Environment) encoder.Encoder { return &textEncoder{} },
	})
}

type textEncoder struct{}

// SetOption does nothing because this encoder does not recognize any option.
func (te *textEncoder) SetOption(option encoder.Option) {}

// WriteZettel does nothing.
func (te *textEncoder) WriteZettel(
// WriteZettel writes metadata and content.
func (te *textEncoder) WriteZettel(w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	v := newVisitor(w)
	if inhMeta {
		te.WriteMeta(&v.b, zn.InhMeta)
	} else {
		te.WriteMeta(&v.b, zn.Zettel.Meta)
		te.WriteMeta(&v.b, zn.Meta)
	}
	v.acceptBlockSlice(zn.Ast)
	length, err := v.b.Flush()
	return length, err
}

// WriteMeta encodes meta data as text.
// WriteMeta encodes metadata as text.
func (te *textEncoder) WriteMeta(w io.Writer, m *meta.Meta) (int, error) {
	b := encoder.NewBufWriter(w)
	for _, pair := range m.Pairs(true) {
		switch meta.Type(pair.Key) {
		case meta.TypeBool:
			if meta.BoolValue(pair.Value) {
				b.WriteString("true")
			} else {
				b.WriteString("false")
			}
		case meta.TypeTagSet:
			for i, tag := range meta.ListFromValue(pair.Value) {
				if i > 0 {
					b.WriteByte(' ')
				}
				b.WriteString(meta.CleanTag(tag))
			}
		case meta.TypeZettelmarkup:
			te.WriteInlines(w, parser.ParseMetadata(pair.Value))
		default:
		b.WriteString(pair.Value)
			b.WriteString(pair.Value)
		}
		b.WriteByte('\n')
	}
	length, err := b.Flush()
	return length, err
}

func (te *textEncoder) WriteContent(w io.Writer, zn *ast.ZettelNode) (int, error) {

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

func init() {
	encoder.Register("zmk", encoder.Info{
		Create: func() encoder.Encoder { return &zmkEncoder{} },
		Create: func(*encoder.Environment) encoder.Encoder { return &zmkEncoder{} },
	})
}

type zmkEncoder struct{}

// SetOption does nothing because this encoder does not recognize any option.
func (ze *zmkEncoder) SetOption(option encoder.Option) {}

// WriteZettel writes the encoded zettel to the writer.
func (ze *zmkEncoder) WriteZettel(
	w io.Writer, zn *ast.ZettelNode, inhMeta bool) (int, error) {
	v := newVisitor(w, ze)
	if inhMeta {
		zn.InhMeta.WriteAsHeader(&v.b, true)
	} else {
		zn.Zettel.Meta.WriteAsHeader(&v.b, true)
		zn.Meta.WriteAsHeader(&v.b, true)
	}
	v.acceptBlockSlice(zn.Ast)
	length, err := v.b.Flush()
	return length, err
}

// WriteMeta encodes meta data as zmk.

module zettelstore.de/z

go 1.15
go 1.16

require (
	github.com/fsnotify/fsnotify v1.4.9
	github.com/pascaldekloe/jwt v1.10.0
	github.com/yuin/goldmark v1.3.2
	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
	golang.org/x/text v0.3.0
	github.com/yuin/goldmark v1.3.3
	golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83
	golang.org/x/term v0.0.0-20201117132131-f5c789dd3221
	golang.org/x/text v0.3.6
)

github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=
github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
github.com/pascaldekloe/jwt v1.10.0 h1:ktcIUV4TPvh404R5dIBEnPCsSwj0sqi3/0+XafE5gJs=
github.com/pascaldekloe/jwt v1.10.0/go.mod h1:TKhllgThT7TOP5rGr2zMLKEDZRAgJfBbtKyVeRsNB9A=
github.com/yuin/goldmark v1.3.2 h1:YjHC5TgyMmHpicTgEqDN0Q96Xo8K6tLXPnmNOHXCgs0=
github.com/yuin/goldmark v1.3.2/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
github.com/yuin/goldmark v1.3.3 h1:37BdQwPx8VOSic8eDSWee6QL9mRpZRm9VJp/QugNrW0=
github.com/yuin/goldmark v1.3.3/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a h1:vclmkQCjlDX5OydZ9wv8rBCcS0QyQY66Mpf/7BZbInM=
golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83 h1:/ZScEX8SfEmUGRHs0gxpqteO5nfNW6axyZbBdw9A12g=
golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9 h1:L2auWcuQIvxz9xSEqzESnV/QN/gNRXNApHi3fYwl2w0=
golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 h1:YyJpGZS1sBuBCzLAR1VEpK193GlqGZbnPFnPV/5Rsb4=
golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/term v0.0.0-20201117132131-f5c789dd3221 h1:/ZHdbVpdR/jk3g30/d4yUL0JU9kksj8+F/bnQUVLGDM=
golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.6 h1:aRYxNxv6iGQlyVaZmk6ZgYEDa+Jg18DxebPSrd6bg1M=
golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

	"context"
	"io"
	"time"

	"zettelstore.de/z/domain"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/place"
	"zettelstore.de/z/place/change"
)

// Enricher is used to update metadata by adding new properties.
type Enricher interface {
	// Enrich computes additional properties and updates the given metadata.
	// It is typically called by zettel reading methods.
	Enrich(ctx context.Context, m *meta.Meta)
}

// Selector is used to select zettel identifier based on selection criteria.
type Selector interface {
	// Select all zettel that contains the given exact word.
	// The word must be normalized through Unicode NKFD.
	Select(word string) id.Set

	// Select all zettel that have a word with the given prefix.
	// The prefix must be normalized through Unicode NKFD.
	SelectPrefix(prefix string) id.Set

	// Select all zettel that contains the given string.
	// The string must be normalized through Unicode NKFD.
	SelectContains(s string) id.Set
}

// NoEnrichContext will signal an enricher that nothing has to be done.
// This is useful for an Indexer, but also for some place.Place calls, when
// just the plain metadata is needed.
func NoEnrichContext(ctx context.Context) context.Context {
	return context.WithValue(ctx, ctxNoEnrichKey, &ctxNoEnrichKey)
}

type ctxNoEnrichType struct{}

var ctxNoEnrichKey ctxNoEnrichType

// DoNotEnrich determines if the context is marked to not enrich metadata.
func DoNotEnrich(ctx context.Context) bool {
	_, ok := ctx.Value(ctxNoEnrichKey).(*ctxNoEnrichType)
	return ok
}

// Port contains all the used functions to access zettel to be indexed.
type Port interface {
	RegisterObserver(func(place.ChangeInfo))
	RegisterObserver(change.Func)
	FetchZids(context.Context) (id.Set, error)
	GetMeta(context.Context, id.Zid) (*meta.Meta, error)
	GetZettel(context.Context, id.Zid) (domain.Zettel, error)
}

// Indexer contains all the functions of an index.
type Indexer interface {
	Enricher
	Selector

	// Start the index. It will read all zettel and store index data for later retrieval.
	Start(Port)

	// Stop the index. No zettel are read any more, but the current index data
	// can stil be retrieved.
	Stop()

	Store StoreStats
}

// Store all relevant zettel data. There may be multiple implementations, i.e.
// memory-based, file-based, based on SQLite, ...
type Store interface {
	Enricher
	Selector

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

	// DeleteZettel removes index data for given zettel.
	// Returns set of zettel identifier that must also be checked for changes.

// StoreStats records statistics about the store.
type StoreStats struct {
	// Zettel is the number of zettel managed by the indexer.
	Zettel int

	// Updates count the number of metadata updates.
	Updates uint64
}

	// Words count the different words stored in the store.
	Words uint64
}

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package indexer allows to search for metadata and content.
package indexer

import (
	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/index"
	"zettelstore.de/z/strfun"
)

func collectZettelIndexData(zn *ast.ZettelNode, refs id.Set, words index.WordSet) {
	ixv := ixVisitor{refs: refs, words: words}
	ast.NewTopDownTraverser(&ixv).VisitBlockSlice(zn.Ast)
}

func collectInlineIndexData(ins ast.InlineSlice, refs id.Set, words index.WordSet) {
	ixv := ixVisitor{refs: refs, words: words}
	ast.NewTopDownTraverser(&ixv).VisitInlineSlice(ins)
}

type ixVisitor struct {
	refs  id.Set
	words index.WordSet
}

// VisitVerbatim collects the verbatim text in the word set.
func (lv *ixVisitor) VisitVerbatim(vn *ast.VerbatimNode) {
	for _, line := range vn.Lines {
		lv.addText(line)
	}
}

// VisitRegion does nothing.
func (lv *ixVisitor) VisitRegion(rn *ast.RegionNode) {}

// VisitHeading does nothing.
func (lv *ixVisitor) VisitHeading(hn *ast.HeadingNode) {}

// VisitHRule does nothing.
func (lv *ixVisitor) VisitHRule(hn *ast.HRuleNode) {}

// VisitList does nothing.
func (lv *ixVisitor) VisitNestedList(ln *ast.NestedListNode) {}

// VisitDescriptionList does nothing.
func (lv *ixVisitor) VisitDescriptionList(dn *ast.DescriptionListNode) {}

// VisitPara does nothing.
func (lv *ixVisitor) VisitPara(pn *ast.ParaNode) {}

// VisitTable does nothing.
func (lv *ixVisitor) VisitTable(tn *ast.TableNode) {}

// VisitBLOB does nothing.
func (lv *ixVisitor) VisitBLOB(bn *ast.BLOBNode) {}

// VisitText collects the text in the word set.
func (lv *ixVisitor) VisitText(tn *ast.TextNode) {
	lv.addText(tn.Text)
}

// VisitTag collects the tag name in the word set.
func (lv *ixVisitor) VisitTag(tn *ast.TagNode) {
	lv.addText(tn.Tag)
}

// VisitSpace does nothing.
func (lv *ixVisitor) VisitSpace(sn *ast.SpaceNode) {}

// VisitBreak does nothing.
func (lv *ixVisitor) VisitBreak(bn *ast.BreakNode) {}

// VisitLink collects the given link as a reference.
func (lv *ixVisitor) VisitLink(ln *ast.LinkNode) {
	ref := ln.Ref
	if ref == nil || !ref.IsZettel() {
		return
	}
	if zid, err := id.Parse(ref.URL.Path); err == nil {
		lv.refs[zid] = true
	}
}

// VisitImage collects the image links as a reference.
func (lv *ixVisitor) VisitImage(in *ast.ImageNode) {
	ref := in.Ref
	if ref == nil || !ref.IsZettel() {
		return
	}
	if zid, err := id.Parse(ref.URL.Path); err == nil {
		lv.refs[zid] = true
	}
}

// VisitCite does nothing.
func (lv *ixVisitor) VisitCite(cn *ast.CiteNode) {}

// VisitFootnote does nothing.
func (lv *ixVisitor) VisitFootnote(fn *ast.FootnoteNode) {}

// VisitMark does nothing.
func (lv *ixVisitor) VisitMark(mn *ast.MarkNode) {}

// VisitFormat does nothing.
func (lv *ixVisitor) VisitFormat(fn *ast.FormatNode) {}

// VisitLiteral collects the literal words in the word set.
func (lv *ixVisitor) VisitLiteral(ln *ast.LiteralNode) {
	lv.addText(ln.Text)
}

func (lv *ixVisitor) addText(s string) {
	for _, word := range strfun.NormalizeWords(s) {
		lv.words[word] = lv.words[word] + 1
	}
}

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

// Package indexer allows to search for metadata and content.
package indexer

import (
	"context"
	"log"
	"runtime/debug"
	"sync"
	"time"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/collect"
	"zettelstore.de/z/domain"
	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/index"
	"zettelstore.de/z/index/memstore"
	"zettelstore.de/z/parser"
	"zettelstore.de/z/place"
	"zettelstore.de/z/place/change"
	"zettelstore.de/z/strfun"
)

type indexer struct {
	store   index.Store
	ar      *anterooms
	ready   chan struct{} // Signal a non-empty anteroom to background task
	done    chan struct{} // Stop background task

	return &indexer{
		store: memstore.New(),
		ar:    newAnterooms(10),
		ready: make(chan struct{}, 1),
	}
}

func (idx *indexer) observer(ci place.ChangeInfo) {
func (idx *indexer) observer(ci change.Info) {
	switch ci.Reason {
	case place.OnReload:
	case change.OnReload:
		idx.ar.Reset()
	case place.OnUpdate:
	case change.OnUpdate:
		idx.ar.Enqueue(ci.Zid, arUpdate)
	case place.OnDelete:
	case change.OnDelete:
		idx.ar.Enqueue(ci.Zid, arDelete)
	default:
		return
	}
	select {
	case idx.ready <- struct{}{}:
	default:

		// Enrich is called indirectly via indexer or enrichment is not requested
		// because of other reasons -> ignore this call, do not update meta data
		return
	}
	idx.store.Enrich(ctx, m)
}

// Select all zettel that contains the given exact word.
// The word must be normalized through Unicode NKFD.
func (idx *indexer) Select(word string) id.Set {
	return idx.store.Select(word)
}

// Select all zettel that have a word with the given prefix.
// The prefix must be normalized through Unicode NKFD.
func (idx *indexer) SelectPrefix(prefix string) id.Set {
	return idx.store.SelectPrefix(prefix)
}

// Select all zettel that contains the given string.
// The string must be normalized through Unicode NKFD.
func (idx *indexer) SelectContains(s string) id.Set {
	return idx.store.SelectContains(s)
}

// ReadStats populates st with indexer statistics.
func (idx *indexer) ReadStats(st *index.IndexerStats) {
	idx.mx.RLock()
	st.LastReload = idx.lastReload
	st.IndexesSinceReload = idx.sinceReload
	st.DurLastIndex = idx.durLastIndex
	idx.mx.RUnlock()
	idx.store.ReadStats(&st.Store)
}

type indexerPort interface {
	getMetaPort
	FetchZids(ctx context.Context) (id.Set, error)
	GetZettel(ctx context.Context, zid id.Zid) (domain.Zettel, error)
}

// indexer runs in the background and updates the index data structures.
// This is the main service of the indexer.
func (idx *indexer) indexer(p indexerPort) {
	// Something may panic. Ensure a running indexer.
	defer func() {
		if err := recover(); err != nil {
		if r := recover(); r != nil {
			log.Println("recovered from:", r)
			debug.PrintStack()
			go idx.indexer(p)
		}
	}()

	timerDuration := 15 * time.Second
	timer := time.NewTimer(timerDuration)
	ctx := index.NoEnrichContext(context.Background())

type getMetaPort interface {
	GetMeta(ctx context.Context, zid id.Zid) (*meta.Meta, error)
}

func (idx *indexer) updateZettel(ctx context.Context, zettel domain.Zettel, p getMetaPort) {
	m := zettel.Meta
	if m.GetBool(meta.KeyNoIndex) {
		// Zettel maybe in index
		toCheck := idx.store.DeleteZettel(ctx, m.Zid)
		idx.checkZettel(toCheck)
		return
	}
	refs := id.NewSet()
	words := make(index.WordSet)
	collectZettelIndexData(parser.ParseZettel(zettel, ""), refs, words)
	zi := index.NewZettelIndex(m.Zid)
	for _, pair := range m.PairsRest(false) {
	for _, pair := range m.Pairs(false) {
		descr := meta.GetDescription(pair.Key)
		if descr.IsComputed() {
			continue
		}
		switch descr.Type {
		case meta.TypeID:
			updateValue(ctx, descr.Inverse, pair.Value, p, zi)
		case meta.TypeIDSet:
			for _, val := range meta.ListFromValue(pair.Value) {
				updateValue(ctx, descr.Inverse, val, p, zi)
			}
		case meta.TypeZettelmarkup:
			collectInlineIndexData(parser.ParseMetadata(pair.Value), refs, words)
		default:
			for _, word := range strfun.NormalizeWords(pair.Value) {
				words[word] = words[word] + 1
		}
	}
	zn := parser.ParseZettel(zettel, "")
			}
		}
	}
	for ref := range refs {
	refs := collect.References(zn)
	updateReferences(ctx, refs.Links, p, zi)
	updateReferences(ctx, refs.Images, p, zi)
		if _, err := p.GetMeta(ctx, ref); err == nil {
			zi.AddBackRef(ref)
		} else {
			zi.AddDeadRef(ref)
		}
	}
	zi.SetWords(words)
	toCheck := idx.store.UpdateReferences(ctx, zi)
	idx.checkZettel(toCheck)
}

func updateValue(ctx context.Context, inverse string, value string, p getMetaPort, zi *index.ZettelIndex) {
	zid, err := id.Parse(value)
	if err != nil {
		return
	}
	if _, err := p.GetMeta(ctx, zid); err != nil {
		zi.AddDeadRef(zid)
		return
	}
	if inverse == "" {
		zi.AddBackRef(zid)
		return
	}
	zi.AddMetaRef(inverse, zid)
}

func updateReferences(ctx context.Context, refs []*ast.Reference, p getMetaPort, zi *index.ZettelIndex) {
	zrefs, _, _ := collect.DivideReferences(refs, false)
	for _, ref := range zrefs {
		updateReference(ctx, ref.URL.Path, p, zi)
	}
}

func updateReference(ctx context.Context, value string, p getMetaPort, zi *index.ZettelIndex) {
	zid, err := id.Parse(value)
	if err != nil {
		return
	}
	if _, err := p.GetMeta(ctx, zid); err != nil {
		zi.AddDeadRef(zid)
		return
	}
	zi.AddBackRef(zid)
}

func (idx *indexer) deleteZettel(zid id.Zid) {
	toCheck := idx.store.DeleteZettel(context.Background(), zid)
	idx.checkZettel(toCheck)
}

func (idx *indexer) checkZettel(s id.Set) {
	for zid := range s {
		idx.ar.Enqueue(zid, arUpdate)
	}
}

// Package memstore stored the index in main memory.
package memstore

import (
	"context"
	"fmt"
	"io"
	"strings"
	"sync"

	"zettelstore.de/z/domain/id"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/index"
)

type metaRefs struct {
	forward  id.Slice
	backward id.Slice
}

type zettelIndex struct {
	dead     id.Slice
	forward  id.Slice
	backward id.Slice
	meta     map[string]metaRefs
	words    []string
}

func (zi *zettelIndex) isEmpty() bool {
	if len(zi.forward) > 0 || len(zi.backward) > 0 || len(zi.dead) > 0 {
	if len(zi.forward) > 0 || len(zi.backward) > 0 || len(zi.dead) > 0 || len(zi.words) > 0 {
		return false
	}
	return zi.meta == nil || len(zi.meta) == 0
}

type memStore struct {
	mx   sync.RWMutex
	idx  map[id.Zid]*zettelIndex
	dead map[id.Zid]id.Slice // map dead refs where they occur
	mx    sync.RWMutex
	idx   map[id.Zid]*zettelIndex
	dead  map[id.Zid]id.Slice // map dead refs where they occur
	words map[string]id.Slice

	// Stats
	updates uint64
}

// New returns a new memory-based index store.
func New() index.Store {
	return &memStore{
		idx:  make(map[id.Zid]*zettelIndex),
		dead: make(map[id.Zid]id.Slice),
		idx:   make(map[id.Zid]*zettelIndex),
		dead:  make(map[id.Zid]id.Slice),
		words: make(map[string]id.Slice),
	}
}

func (ms *memStore) Enrich(ctx context.Context, m *meta.Meta) {
	if ms.doEnrich(ctx, m) {
		ms.mx.Lock()
		ms.updates++
		ms.mx.Unlock()
	}
}

func (ms *memStore) doEnrich(ctx context.Context, m *meta.Meta) bool {
	ms.mx.RLock()
	defer ms.mx.RUnlock()
	zi, ok := ms.idx[m.Zid]
	if !ok {
		return
		return false
	}
	var updated bool
	if len(zi.dead) > 0 {
		m.Set(meta.KeyDead, zi.dead.String())
		updated = true
	}
	back := removeOtherMetaRefs(m, zi.backward.Copy())

			}
		}
	}
	if len(back) > 0 {
		m.Set(meta.KeyBack, back.String())
		updated = true
	}
	if updated {
		ms.updates++
	return updated
}

// Select all zettel that contains the given exact word.
// The word must be normalized through Unicode NKFD.
func (ms *memStore) Select(word string) id.Set {
	ms.mx.RLock()
	defer ms.mx.RUnlock()
	if refs, ok := ms.words[word]; ok {
		return id.NewSet(refs...)
	}
	return nil
}

// Select all zettel that have a word with the given prefix.
// The prefix must be normalized through Unicode NKFD.
func (ms *memStore) SelectPrefix(prefix string) id.Set {
	ms.mx.RLock()
	defer ms.mx.RUnlock()
	return ms.selectWithPred(prefix, strings.HasPrefix)
}

// Select all zettel that contains the given string.
// The string must be normalized through Unicode NKFD.
func (ms *memStore) SelectContains(s string) id.Set {
	ms.mx.RLock()
	defer ms.mx.RUnlock()
	return ms.selectWithPred(s, strings.Contains)
}

func (ms *memStore) selectWithPred(s string, pred func(string, string) bool) id.Set {
	result := id.NewSet()
	for word, refs := range ms.words {
		if !pred(word, s) {
			continue
		}
		for _, ref := range refs {
			result[ref] = true
		}
	}
	return result
}

func removeOtherMetaRefs(m *meta.Meta, back id.Slice) id.Slice {
	for _, p := range m.PairsRest(false) {
		switch meta.Type(p.Key) {
		case meta.TypeID:
			if zid, err := id.Parse(p.Value); err == nil {

		toCheck = id.NewSet(refs...)
		delete(ms.dead, zidx.Zid)
	}

	ms.updateDeadReferences(zidx, zi)
	ms.updateForwardBackwardReferences(zidx, zi)
	ms.updateMetadataReferences(zidx, zi)
	ms.updateWords(zidx, zi)

	// Check if zi must be inserted into ms.idx
	if !ziExist && !zi.isEmpty() {
		ms.idx[zidx.Zid] = zi
	}

	return toCheck

			bmr := bzi.meta[key]
			bmr.backward = addRef(bmr.backward, zidx.Zid)
			bzi.meta[key] = bmr
		}
		ms.removeInverseMeta(zidx.Zid, key, remRefs)
	}
}

func (ms *memStore) updateWords(zidx *index.ZettelIndex, zi *zettelIndex) {
	// Must only be called if ms.mx is write-locked!
	words := zidx.GetWords()
	newWords, removeWords := words.Diff(zi.words)
	for _, word := range newWords {
		if refs, ok := ms.words[word]; ok {
			ms.words[word] = addRef(refs, zidx.Zid)
			continue
		}
		ms.words[word] = id.Slice{zidx.Zid}
	}
	for _, word := range removeWords {
		refs, ok := ms.words[word]
		if !ok {
			continue
		}
		refs2 := remRef(refs, zidx.Zid)
		if len(refs2) == 0 {
			delete(ms.words, word)
			continue
		}
		ms.words[word] = refs2
	}
	zi.words = words.Words()
}

func (ms *memStore) getEntry(zid id.Zid) *zettelIndex {
	// Must only be called if ms.mx is write-locked!
	if zi, ok := ms.idx[zid]; ok {
		return zi
	}
	zi := &zettelIndex{}

	ms.deleteDeadSources(zid, zi)
	toCheck := ms.deleteForwardBackward(zid, zi)
	if len(zi.meta) > 0 {
		for key, mrefs := range zi.meta {
			ms.removeInverseMeta(zid, key, mrefs.forward)
		}
	}
	ms.deleteWords(zid, zi.words)
	delete(ms.idx, zid)
	return toCheck
}

func (ms *memStore) deleteDeadSources(zid id.Zid, zi *zettelIndex) {
	// Must only be called if ms.mx is write-locked!
	for _, ref := range zi.dead {

			delete(bzi.meta, key)
			if len(bzi.meta) == 0 {
				bzi.meta = nil
			}
		}
	}
}

func (ms *memStore) deleteWords(zid id.Zid, words []string) {
	// Must only be called if ms.mx is write-locked!
	for _, word := range words {
		refs, ok := ms.words[word]
		if !ok {
			continue
		}
		refs2 := remRef(refs, zid)
		if len(refs2) == 0 {
			delete(ms.words, word)
			continue
		}
		ms.words[word] = refs2
	}
}

func (ms *memStore) ReadStats(st *index.StoreStats) {
	ms.mx.RLock()
	st.Zettel = len(ms.idx)
	st.Updates = ms.updates
	st.Words = uint64(len(ms.words))
	ms.mx.RUnlock()
}

func (ms *memStore) Write(w io.Writer) {
	ms.mx.RLock()
	defer ms.mx.RUnlock()

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package index allows to search for metadata and content.
package index

// WordSet contains the set of all words, with the count of their occurrences.
type WordSet map[string]int

// Words gives the slice of all words in the set.
func (ws WordSet) Words() []string {
	if len(ws) == 0 {
		return nil
	}
	words := make([]string, 0, len(ws))
	for w := range ws {
		words = append(words, w)
	}
	return words
}

// Diff calculates the word slice to be added and to be removed from oldWords
// to get the given word set.
func (ws WordSet) Diff(oldWords []string) (newWords, removeWords []string) {
	if len(ws) == 0 {
		return nil, oldWords
	}
	if len(oldWords) == 0 {
		return ws.Words(), nil
	}
	oldSet := make(WordSet, len(oldWords))
	for _, ow := range oldWords {
		if _, ok := ws[ow]; ok {
			oldSet[ow] = 1
			continue
		}
		removeWords = append(removeWords, ow)
	}
	for w := range ws {
		if _, ok := oldSet[w]; ok {
			continue
		}
		newWords = append(newWords, w)
	}
	return newWords, removeWords
}

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package index allows to search for metadata and content.
package index_test

import (
	"sort"
	"testing"

	"zettelstore.de/z/index"
)

func equalWordList(exp, got []string) bool {
	if len(exp) != len(got) {
		return false
	}
	if len(got) == 0 {
		return len(exp) == 0
	}
	sort.Strings(got)
	for i, w := range exp {
		if w != got[i] {
			return false
		}
	}
	return true
}

func TestWordsWords(t *testing.T) {
	testcases := []struct {
		words index.WordSet
		exp   []string
	}{
		{nil, nil},
		{index.WordSet{}, nil},
		{index.WordSet{"a": 1, "b": 2}, []string{"a", "b"}},
	}
	for i, tc := range testcases {
		got := tc.words.Words()
		if !equalWordList(tc.exp, got) {
			t.Errorf("%d: %v.Words() == %v, but got %v", i, tc.words, tc.exp, got)
		}
	}
}

func TestWordsDiff(t *testing.T) {
	testcases := []struct {
		cur        index.WordSet
		old        []string
		expN, expR []string
	}{
		{nil, nil, nil, nil},
		{index.WordSet{}, []string{}, nil, nil},
		{index.WordSet{"a": 1}, []string{}, []string{"a"}, nil},
		{index.WordSet{"a": 1}, []string{"b"}, []string{"a"}, []string{"b"}},
		{index.WordSet{}, []string{"b"}, nil, []string{"b"}},
		{index.WordSet{"a": 1}, []string{"a"}, nil, nil},
	}
	for i, tc := range testcases {
		gotN, gotR := tc.cur.Diff(tc.old)
		if !equalWordList(tc.expN, gotN) {
			t.Errorf("%d: %v.Diff(%v)->new %v, but got %v", i, tc.cur, tc.old, tc.expN, gotN)
		}
		if !equalWordList(tc.expR, gotR) {
			t.Errorf("%d: %v.Diff(%v)->rem %v, but got %v", i, tc.cur, tc.old, tc.expR, gotR)
		}
	}
}

// ZettelIndex contains all index data of a zettel.
type ZettelIndex struct {
	Zid      id.Zid            // zid of the indexed zettel
	backrefs id.Set            // set of back references
	metarefs map[string]id.Set // references to inverse keys
	deadrefs id.Set            // set of dead references
	words    WordSet
}

// NewZettelIndex creates a new zettel index.
func NewZettelIndex(zid id.Zid) *ZettelIndex {
	return &ZettelIndex{
		Zid:      zid,
		backrefs: id.NewSet(),

}

// AddDeadRef adds a dead reference to a zettel.
func (zi *ZettelIndex) AddDeadRef(zid id.Zid) {
	zi.deadrefs[zid] = true
}

// SetWords sets the words to the given value.
func (zi *ZettelIndex) SetWords(words WordSet) { zi.words = words }

// GetDeadRefs returns all dead references as a sorted list.
func (zi *ZettelIndex) GetDeadRefs() id.Slice {
	return zi.deadrefs.Sort()
	return zi.deadrefs.Sorted()
}

// GetBackRefs returns all back references as a sorted list.
func (zi *ZettelIndex) GetBackRefs() id.Slice {
	return zi.backrefs.Sort()
	return zi.backrefs.Sorted()
}

// GetMetaRefs returns all meta references as a map of strings to a sorted list of references
func (zi *ZettelIndex) GetMetaRefs() map[string]id.Slice {
	if len(zi.metarefs) == 0 {
		return nil
	}
	result := make(map[string]id.Slice, len(zi.metarefs))
	for key, refs := range zi.metarefs {
		result[key] = refs.Sort()
		result[key] = refs.Sorted()
	}
	return result
}

// GetWords returns a reference to the WordSet. It must not be modified.
func (zi *ZettelIndex) GetWords() WordSet { return zi.words }

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

		if r == '\t' {
			return ' '
		}
		return r
	}
	return EOS
}

// IsEOLEOS returns true if char is either EOS or EOL.
func IsEOLEOS(ch rune) bool {
	switch ch {
	case EOS, '\n', '\r':
		return true
	}
	return false
}

// EatEOL transforms both "\r" and "\r\n" into "\n".
func (inp *Input) EatEOL() {
	switch inp.Ch {
	case '\r':
		if inp.Peek() == '\n' {
			inp.Next()

func (inp *Input) ScanEntity() (res string, success bool) {
	if inp.Ch != '&' {
		return "", false
	}
	pos := inp.Pos
	inp.Next()
	if inp.Ch == '#' {
		code := 0
		inp.Next()
		if inp.Ch == 'x' || inp.Ch == 'X' {
			return inp.scanEntityBase16()
		}
		return inp.scanEntityBase10()
	}
	return inp.scanEntityNamed(pos)
}
			// Base 16 code
			inp.Next()
			if inp.Ch == ';' {
				return "", false
			}
			for {
				switch ch := inp.Ch; ch {
				case ';':
					inp.Next()
					return string(rune(code)), true
				case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
					code = 16*code + int(ch-'0')
				case 'a', 'b', 'c', 'd', 'e', 'f':
					code = 16*code + int(ch-'a'+10)
				case 'A', 'B', 'C', 'D', 'E', 'F':
					code = 16*code + int(ch-'A'+10)
				default:
					return "", false
				}
				if code > unicode.MaxRune {
					return "", false
				}
				inp.Next()
			}
		}

func (inp *Input) scanEntityBase16() (string, bool) {
	inp.Next()
	if inp.Ch == ';' {
		return "", false
	}
	code := 0
	for {
		switch ch := inp.Ch; ch {
		case ';':
			inp.Next()
			return string(rune(code)), true
		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
			code = 16*code + int(ch-'0')
		case 'a', 'b', 'c', 'd', 'e', 'f':
			code = 16*code + int(ch-'a'+10)
		case 'A', 'B', 'C', 'D', 'E', 'F':
			code = 16*code + int(ch-'A'+10)
		default:
			return "", false
		}
		if code > unicode.MaxRune {
			return "", false
		}
		inp.Next()
	}
}

func (inp *Input) scanEntityBase10() (string, bool) {
		// Base 10 code
		if inp.Ch == ';' {
			return "", false
		}
		for {
			switch ch := inp.Ch; ch {
			case ';':
				inp.Next()
				return string(rune(code)), true
			case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
				code = 10*code + int(ch-'0')
			default:
				return "", false
			}
			if code > unicode.MaxRune {
				return "", false
			}
			inp.Next()
		}
	}

	// Base 10 code
	if inp.Ch == ';' {
		return "", false
	}
	code := 0
	for {
		switch ch := inp.Ch; ch {
		case ';':
			inp.Next()
			return string(rune(code)), true
		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
			code = 10*code + int(ch-'0')
		default:
			return "", false
		}
		if code > unicode.MaxRune {
			return "", false
		}
		inp.Next()
	}
}
func (inp *Input) scanEntityNamed(pos int) (string, bool) {
	for {
		switch inp.Ch {
		case EOS, '\n', '\r':
			return "", false
		case ';':
			inp.Next()
			es := inp.Src[pos:inp.Pos]

//-----------------------------------------------------------------------------
// Copyright (c) 2020 Detlef Stern
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

// Package cleaner provides funxtions to clean up the parsed AST.
package cleaner

import (
	"strconv"
	"strings"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/strfun"
)

// CleanupBlockSlice cleans the given block slice.
func CleanupBlockSlice(bs ast.BlockSlice) {
	cv := &cleanupVisitor{
		textEnc: encoder.Create("text", nil),
		doMark:  false,
	}
	t := ast.NewTopDownTraverser(cv)
	t.VisitBlockSlice(bs)
	if cv.hasMark {
		cv.doMark = true
		t.VisitBlockSlice(bs)
	}
}

type cleanupVisitor struct {
	textEnc encoder.Encoder
	ids     map[string]ast.Node
	hasMark bool
	doMark  bool
}

// VisitVerbatim does nothing.
func (cv *cleanupVisitor) VisitVerbatim(vn *ast.VerbatimNode) {}

// VisitRegion does nothing.
func (cv *cleanupVisitor) VisitRegion(rn *ast.RegionNode) {}

// VisitHeading calculates the heading slug.
func (cv *cleanupVisitor) VisitHeading(hn *ast.HeadingNode) {
	if cv.doMark || hn == nil || hn.Inlines == nil {
		return
	}
	var sb strings.Builder
	_, err := cv.textEnc.WriteInlines(&sb, hn.Inlines)
	if err != nil {
		return
	}
	s := strfun.Slugify(sb.String())
	if len(s) > 0 {
		hn.Slug = cv.addIdentifier(s, hn)
	}
}

// VisitHRule does nothing.
func (cv *cleanupVisitor) VisitHRule(hn *ast.HRuleNode) {}

// VisitList does nothing.
func (cv *cleanupVisitor) VisitNestedList(ln *ast.NestedListNode) {}

// VisitDescriptionList does nothing.
func (cv *cleanupVisitor) VisitDescriptionList(dn *ast.DescriptionListNode) {}

// VisitPara does nothing.
func (cv *cleanupVisitor) VisitPara(pn *ast.ParaNode) {}

// VisitTable does nothing.
func (cv *cleanupVisitor) VisitTable(tn *ast.TableNode) {}

// VisitBLOB does nothing.
func (cv *cleanupVisitor) VisitBLOB(bn *ast.BLOBNode) {}

// VisitText does nothing.
func (cv *cleanupVisitor) VisitText(tn *ast.TextNode) {}

// VisitTag does nothing.
func (cv *cleanupVisitor) VisitTag(tn *ast.TagNode) {}

// VisitSpace does nothing.
func (cv *cleanupVisitor) VisitSpace(sn *ast.SpaceNode) {}

// VisitBreak does nothing.
func (cv *cleanupVisitor) VisitBreak(bn *ast.BreakNode) {}

// VisitLink collects the given link as a reference.
func (cv *cleanupVisitor) VisitLink(ln *ast.LinkNode) {}

// VisitImage collects the image links as a reference.
func (cv *cleanupVisitor) VisitImage(in *ast.ImageNode) {}

// VisitCite does nothing.
func (cv *cleanupVisitor) VisitCite(cn *ast.CiteNode) {}

// VisitFootnote does nothing.
func (cv *cleanupVisitor) VisitFootnote(fn *ast.FootnoteNode) {}

// VisitMark checks for duplicate marks and changes them.
func (cv *cleanupVisitor) VisitMark(mn *ast.MarkNode) {
	if mn == nil {
		return
	}
	if !cv.doMark {
		cv.hasMark = true
		return
	}
	if mn.Text == "" {
		mn.Text = cv.addIdentifier("*", mn)
		return
	}
	mn.Text = cv.addIdentifier(mn.Text, mn)
}

// VisitFormat does nothing.
func (cv *cleanupVisitor) VisitFormat(fn *ast.FormatNode) {}

// VisitLiteral does nothing.
func (cv *cleanupVisitor) VisitLiteral(ln *ast.LiteralNode) {}

func (cv *cleanupVisitor) addIdentifier(id string, node ast.Node) string {
	if cv.ids == nil {
		cv.ids = map[string]ast.Node{id: node}
		return id
	}
	if n, ok := cv.ids[id]; ok && n != node {
		prefix := id + "-"
		for count := 1; ; count++ {
			newID := prefix + strconv.Itoa(count)
			if n, ok := cv.ids[newID]; !ok || n == node {
				cv.ids[newID] = node
				return newID
			}
		}
	}
	cv.ids[id] = node
	return id
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020-2021 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.
//-----------------------------------------------------------------------------

// Package parser provides a generic interface to a range of different parsers.
package parser

import (
	"strconv"
	"strings"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/encoder"
	"zettelstore.de/z/strfun"

	// Ensure that the text encoder is available
	_ "zettelstore.de/z/encoder/textenc"
)

func cleanupBlockSlice(bs ast.BlockSlice) {
	cv := &cleanupVisitor{
		textEnc: encoder.Create("text"),
		doMark:  false,
	}
	t := ast.NewTopDownTraverser(cv)
	t.VisitBlockSlice(bs)
	if cv.hasMark {
		cv.doMark = true
		t.VisitBlockSlice(bs)
	}
}

type cleanupVisitor struct {
	textEnc encoder.Encoder
	ids     map[string]ast.Node
	hasMark bool
	doMark  bool
}

// VisitVerbatim does nothing.
func (cv *cleanupVisitor) VisitVerbatim(vn *ast.VerbatimNode) {}

// VisitRegion does nothing.
func (cv *cleanupVisitor) VisitRegion(rn *ast.RegionNode) {}

// VisitHeading calculates the heading slug.
func (cv *cleanupVisitor) VisitHeading(hn *ast.HeadingNode) {
	if cv.doMark || hn == nil || hn.Inlines == nil {
		return
	}
	var sb strings.Builder
	_, err := cv.textEnc.WriteInlines(&sb, hn.Inlines)
	if err != nil {
		return
	}
	s := strfun.Slugify(sb.String())
	if len(s) > 0 {
		hn.Slug = cv.addIdentifier(s, hn)
	}
}

// VisitHRule does nothing.
func (cv *cleanupVisitor) VisitHRule(hn *ast.HRuleNode) {}

// VisitList does nothing.
func (cv *cleanupVisitor) VisitNestedList(ln *ast.NestedListNode) {}

// VisitDescriptionList does nothing.
func (cv *cleanupVisitor) VisitDescriptionList(dn *ast.DescriptionListNode) {}

// VisitPara does nothing.
func (cv *cleanupVisitor) VisitPara(pn *ast.ParaNode) {}

// VisitTable does nothing.
func (cv *cleanupVisitor) VisitTable(tn *ast.TableNode) {}

// VisitBLOB does nothing.
func (cv *cleanupVisitor) VisitBLOB(bn *ast.BLOBNode) {}

// VisitText does nothing.
func (cv *cleanupVisitor) VisitText(tn *ast.TextNode) {}

// VisitTag does nothing.
func (cv *cleanupVisitor) VisitTag(tn *ast.TagNode) {}

// VisitSpace does nothing.
func (cv *cleanupVisitor) VisitSpace(sn *ast.SpaceNode) {}

// VisitBreak does nothing.
func (cv *cleanupVisitor) VisitBreak(bn *ast.BreakNode) {}

// VisitLink collects the given link as a reference.
func (cv *cleanupVisitor) VisitLink(ln *ast.LinkNode) {}

// VisitImage collects the image links as a reference.
func (cv *cleanupVisitor) VisitImage(in *ast.ImageNode) {}

// VisitCite does nothing.
func (cv *cleanupVisitor) VisitCite(cn *ast.CiteNode) {}

// VisitFootnote does nothing.
func (cv *cleanupVisitor) VisitFootnote(fn *ast.FootnoteNode) {}

// VisitMark checks for duplicate marks and changes them.
func (cv *cleanupVisitor) VisitMark(mn *ast.MarkNode) {
	if mn == nil {
		return
	}
	if !cv.doMark {
		cv.hasMark = true
		return
	}
	if mn.Text == "" {
		mn.Text = cv.addIdentifier("*", mn)
		return
	}
	mn.Text = cv.addIdentifier(mn.Text, mn)
}

// VisitFormat does nothing.
func (cv *cleanupVisitor) VisitFormat(fn *ast.FormatNode) {}

// VisitLiteral does nothing.
func (cv *cleanupVisitor) VisitLiteral(ln *ast.LiteralNode) {}

func (cv *cleanupVisitor) addIdentifier(id string, node ast.Node) string {
	if cv.ids == nil {
		cv.ids = map[string]ast.Node{id: node}
		return id
	}
	if n, ok := cv.ids[id]; ok && n != node {
		prefix := id + "-"
		for count := 1; ; count++ {
			newID := prefix + strconv.Itoa(count)
			if n, ok := cv.ids[newID]; !ok || n == node {
				cv.ids[newID] = node
				return newID
			}
		}
	}
	cv.ids[id] = node
	return id
}

	panic("markdown.parseInline not yet implemented")
}

func parseMarkdown(inp *input.Input) *mdP {
	source := []byte(inp.Src[inp.Pos:])
	parser := gm.DefaultParser()
	node := parser.Parse(gmText.NewReader(source))
	textEnc := encoder.Create("text")
	textEnc := encoder.Create("text", nil)
	return &mdP{source: source, docNode: node, textEnc: textEnc}
}

type mdP struct {
	source  []byte
	docNode gmAst.Node
	textEnc encoder.Encoder

	case 2:
		result = append(result, &ast.SpaceNode{Lexeme: text[lastPos:]})
	default:
		panic(fmt.Sprintf("Unexpected state %v", state))
	}
	return result
}

var ignoreAfterBS = map[byte]bool{
	'!': true, '"': true, '#': true, '$': true, '%': true, '&': true,
	'\'': true, '(': true, ')': true, '*': true, '+': true, ',': true,
	'-': true, '.': true, '/': true, ':': true, ';': true, '<': true,
	'=': true, '>': true, '?': true, '@': true, '[': true, '\\': true,
	']': true, '^': true, '_': true, '`': true, '{': true, '|': true,
	'}': true, '~': true,
}

// cleanText removes backslashes from TextNodes and expands entities
func cleanText(text string, cleanBS bool) string {
	if text == "" {
		return ""
	}
	lastPos := 0
	var sb strings.Builder
	for pos, ch := range text {
		if pos < lastPos {
			continue
		}
		if ch == '&' {
			inp := input.NewInput(text[pos:])
			if s, ok := inp.ScanEntity(); ok {
				sb.WriteString(text[lastPos:pos])
				sb.WriteString(s)
				lastPos = pos + inp.Pos
			}
			continue
		}
		if cleanBS && ch == '\\' && pos < len(text)-1 {
		if cleanBS && ch == '\\' && pos < len(text)-1 && ignoreAfterBS[text[pos+1]] {
			switch b := text[pos+1]; b {
			case '!', '"', '#', '$', '%', '&', '\'', '(', ')', '*', '+',
				',', '-', '.', '/', ':', ';', '<', '=', '>', '?', '@',
				'[', '\\', ']', '^', '_', '`', '{', '|', '}', '~':
				sb.WriteString(text[lastPos:pos])
				sb.WriteByte(b)
				lastPos = pos + 2
			sb.WriteString(text[lastPos:pos])
			sb.WriteByte(text[pos+1])
			lastPos = pos + 2
			}
		}
	}
	if lastPos == 0 {
		return text
	}
	if lastPos < len(text) {
		sb.WriteString(text[lastPos:])

	"log"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/config/runtime"
	"zettelstore.de/z/domain"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/input"
	"zettelstore.de/z/parser/cleaner"
)

// Info describes a single parser.
//
// Before ParseBlocks() or ParseInlines() is called, ensure the input stream to
// be valid. This can ce achieved on calling inp.Next() after the input stream
// was created.

	log.Printf("No parser for %q found", name)
	panic("No default parser registered")
}

// ParseBlocks parses some input and returns a slice of block nodes.
func ParseBlocks(inp *input.Input, m *meta.Meta, syntax string) ast.BlockSlice {
	bs := Get(syntax).ParseBlocks(inp, m, syntax)
	cleanupBlockSlice(bs)
	cleaner.CleanupBlockSlice(bs)
	return bs
}

// ParseInlines parses some input and returns a slice of inline nodes.
func ParseInlines(inp *input.Input, syntax string) ast.InlineSlice {
	return Get(syntax).ParseInlines(inp, syntax)
}

// ParseMetadata parses a string as Zettelmarkup, resulting in an inline slice.
// ParseTitle parses the title of a zettel, always as Zettelmarkup
func ParseTitle(title string) ast.InlineSlice {
// Typically used to parse the title or other metadata of type Zettelmarkup.
func ParseMetadata(title string) ast.InlineSlice {
	return ParseInlines(input.NewInput(title), meta.ValueSyntaxZmk)
}

// ParseZettel parses the zettel based on the syntax.
func ParseZettel(zettel domain.Zettel, syntax string) *ast.ZettelNode {
	m := zettel.Meta
	inhMeta := runtime.AddDefaultValues(zettel.Meta)
	inhMeta := runtime.AddDefaultValues(m)
	if syntax == "" {
		syntax, _ = inhMeta.Get(meta.KeySyntax)
	}
	title, _ := inhMeta.Get(meta.KeyTitle)
	parseMeta := inhMeta
	if syntax == meta.ValueSyntaxNone {
		parseMeta = m
	}
	return &ast.ZettelNode{
		Meta:    m,
		Zettel:  zettel,
		Content: zettel.Content,
		Zid:     m.Zid,
		InhMeta: inhMeta,
		Title:   ParseTitle(title),
		Ast:     ParseBlocks(input.NewInput(zettel.Content.AsString()), parseMeta, syntax),
	}
}

		success := false

		switch inp.Ch {
		case input.EOS:
			return nil, false
		case '\n', '\r':
			inp.EatEOL()
			for _, l := range cp.lists {
			cp.cleanupListsAfterEOL()
				if lits := len(l.Items); lits > 0 {
					l.Items[lits-1] = append(l.Items[lits-1], &nullItemNode{})
				}
			}
			if cp.descrl != nil {
				defPos := len(cp.descrl.Descriptions) - 1
				if ldds := len(cp.descrl.Descriptions[defPos].Descriptions); ldds > 0 {
					cp.descrl.Descriptions[defPos].Descriptions[ldds-1] = append(
						cp.descrl.Descriptions[defPos].Descriptions[ldds-1], &nullDescriptionNode{})
				}
			}
			return nil, false
		case ':':
			bn, success = cp.parseColon()
		case '`', runeModGrave, '%':
			cp.clearStacked()
			bn, success = cp.parseVerbatim()
		case '"', '<':

	pn := cp.parsePara()
	if lastPara != nil {
		lastPara.Inlines = append(lastPara.Inlines, pn.Inlines...)
		return nil, true
	}
	return pn, false
}

func (cp *zmkP) cleanupListsAfterEOL() {
	for _, l := range cp.lists {
		if lits := len(l.Items); lits > 0 {
			l.Items[lits-1] = append(l.Items[lits-1], &nullItemNode{})
		}
	}
	if cp.descrl != nil {
		defPos := len(cp.descrl.Descriptions) - 1
		if ldds := len(cp.descrl.Descriptions[defPos].Descriptions); ldds > 0 {
			cp.descrl.Descriptions[defPos].Descriptions[ldds-1] = append(
				cp.descrl.Descriptions[defPos].Descriptions[ldds-1], &nullDescriptionNode{})
		}
	}
}

// parseColon determines which element should be parsed.
func (cp *zmkP) parseColon() (ast.BlockNode, bool) {
	inp := cp.inp
	if inp.PeekN(1) == ':' {
		cp.clearStacked()
		return cp.parseRegion()

	var lastPara *ast.ParaNode
	inp.EatEOL()
	for {
		posL := inp.Pos
		switch inp.Ch {
		case fch:
			if cp.countDelim(fch) >= cnt {
				cp.clearStacked() // remove any lists defined in the region
				for inp.Ch == ' ' {
					inp.Next()
				}
				for {
					switch inp.Ch {
					case input.EOS, '\n', '\r':
						return rn, true
					}
					in := cp.parseInline()
				cp.parseRegionLastLine(rn)
					if in == nil {
						return rn, true
				return rn, true
					}
					rn.Inlines = append(rn.Inlines, in)
				}
			}
			inp.SetPos(posL)
		case input.EOS:
			return nil, false
		}
		bn, cont := cp.parseBlock(lastPara)
		if bn != nil {
			rn.Blocks = append(rn.Blocks, bn)
		}
		if !cont {
			lastPara, _ = bn.(*ast.ParaNode)
		}
	}
}

func (cp *zmkP) parseRegionLastLine(rn *ast.RegionNode) {
	cp.clearStacked() // remove any lists defined in the region
	cp.skipSpace()
	for {
		switch cp.inp.Ch {
		case input.EOS, '\n', '\r':
			return
		}
		in := cp.parseInline()
		if in == nil {
			return
		}
		rn.Inlines = append(rn.Inlines, in)
	}

}

// parseHeading parses a head line.
func (cp *zmkP) parseHeading() (hn *ast.HeadingNode, success bool) {
	inp := cp.inp
	lvl := cp.countDelim(inp.Ch)
	if lvl < 3 {
		return nil, false
	}
	if lvl > 7 {
		lvl = 7
	}
	if inp.Ch != ' ' {
		return nil, false
	}
	inp.Next()
	for inp.Ch == ' ' {
		inp.Next()
	cp.skipSpace()
	}
	hn = &ast.HeadingNode{Level: lvl - 1}
	for {
		switch inp.Ch {
		case input.EOS, '\n', '\r':
		if input.IsEOLEOS(inp.Ch) {
			return hn, true
		}
		in := cp.parseInline()
		if in == nil {
			return hn, true
		}
		if inp.Ch == '{' {

var mapRuneNestedList = map[rune]ast.NestedListCode{
	'*': ast.NestedListUnordered,
	'#': ast.NestedListOrdered,
	'>': ast.NestedListQuote,
}

// parseList parses a list.
// parseNestedList parses a list.
func (cp *zmkP) parseNestedList() (res ast.BlockNode, success bool) {
	inp := cp.inp
	codes := []ast.NestedListCode{}
loopInit:
	codes := cp.parseNestedListCodes()
	if codes == nil {
		return nil, false
	}
	cp.skipSpace()
	if codes[len(codes)-1] != ast.NestedListQuote && input.IsEOLEOS(inp.Ch) {
		return nil, false
	}

	if len(codes) < len(cp.lists) {
		cp.lists = cp.lists[:len(codes)]
	}
	ln, newLnCount := cp.buildNestedList(codes)
	ln.Items = append(ln.Items, ast.ItemSlice{cp.parseLinePara()})
	return cp.cleanupParsedNestedList(newLnCount)
}

func (cp *zmkP) parseNestedListCodes() []ast.NestedListCode {
	inp := cp.inp
	codes := make([]ast.NestedListCode, 0, 4)
	for {
		code, ok := mapRuneNestedList[inp.Ch]
		if !ok {
			panic(fmt.Sprintf("%q is not a region char", inp.Ch))
		}
		codes = append(codes, code)
		inp.Next()
		switch inp.Ch {
		case '*', '#', '>':
		case ' ', input.EOS, '\n', '\r':
			break loopInit
			return codes
		default:
			return nil, false
			return nil
		}
	}
	for inp.Ch == ' ' {
		inp.Next()
	}
	if codes[len(codes)-1] != ast.NestedListQuote {
		switch inp.Ch {
		case input.EOS, '\n', '\r':
			return nil, false
		}
	}

	if len(codes) < len(cp.lists) {
		cp.lists = cp.lists[:len(codes)]
	}
	var ln *ast.NestedListNode
	newLnCount := 0
}

func (cp *zmkP) buildNestedList(codes []ast.NestedListCode) (ln *ast.NestedListNode, newLnCount int) {
	for i, code := range codes {
		if i < len(cp.lists) {
			if cp.lists[i].Code != code {
				ln = &ast.NestedListNode{Code: code}
				newLnCount++
				cp.lists[i] = ln
				cp.lists = cp.lists[:i+1]
			} else {
				ln = cp.lists[i]
			}
		} else {
			ln = &ast.NestedListNode{Code: code}
			newLnCount++
			cp.lists = append(cp.lists, ln)
		}
	}
	return ln, newLnCount
}
	ln.Items = append(ln.Items, ast.ItemSlice{cp.parseLinePara()})

func (cp *zmkP) cleanupParsedNestedList(newLnCount int) (res ast.BlockNode, success bool) {
	listDepth := len(cp.lists)
	for i := 0; i < newLnCount; i++ {
		childPos := listDepth - i - 1
		parentPos := childPos - 1
		if parentPos < 0 {
			return cp.lists[0], true
		}
		if prevItems := cp.lists[parentPos].Items; len(prevItems) > 0 {
			lastItem := len(prevItems) - 1
			prevItems[lastItem] = append(prevItems[lastItem], cp.lists[childPos])
		} else {
			cp.lists[parentPos].Items = []ast.ItemSlice{{cp.lists[childPos]}}
		}
	}
	return nil, true

}

// parseDefTerm parses a term of a definition list.
func (cp *zmkP) parseDefTerm() (res ast.BlockNode, success bool) {
	inp := cp.inp
	inp.Next()
	if inp.Ch != ' ' {
		return nil, false
	}
	inp.Next()
	for inp.Ch == ' ' {
		inp.Next()
	cp.skipSpace()
	}
	descrl := cp.descrl
	if descrl == nil {
		descrl = &ast.DescriptionListNode{}
		cp.descrl = descrl
	}
	descrl.Descriptions = append(descrl.Descriptions, ast.Description{})
	defPos := len(descrl.Descriptions) - 1

func (cp *zmkP) parseDefDescr() (res ast.BlockNode, success bool) {
	inp := cp.inp
	inp.Next()
	if inp.Ch != ' ' {
		return nil, false
	}
	inp.Next()
	for inp.Ch == ' ' {
		inp.Next()
	cp.skipSpace()
	}
	descrl := cp.descrl
	if descrl == nil || len(descrl.Descriptions) == 0 {
		return nil, false
	}
	defPos := len(descrl.Descriptions) - 1
	if descrl.Descriptions[defPos].Term == nil {
		return nil, false

}

// parseCell parses one single cell of a table row.
func (cp *zmkP) parseCell() *ast.TableCell {
	inp := cp.inp
	var slice ast.InlineSlice
	for {
		switch inp.Ch {
		case input.EOS, '\n', '\r':
		if input.IsEOLEOS(inp.Ch) {
			if len(slice) == 0 {
				return nil
			}
			fallthrough
		case '|':
			return &ast.TableCell{Inlines: slice}
		}
		if inp.Ch == '|' {
			return &ast.TableCell{Inlines: slice}
		}
		slice = append(slice, cp.parseInline())
	}
}

	default:
		return cp.parseBackslashRest()
	}
}

func (cp *zmkP) parseBackslashRest() *ast.TextNode {
	inp := cp.inp
	switch inp.Ch {
	case input.EOS, '\n', '\r':
	if input.IsEOLEOS(inp.Ch) {
		return &ast.TextNode{Text: "\\"}
	}
	case ' ':
	if inp.Ch == ' ' {
		inp.Next()
		return &ast.TextNode{Text: "\u00a0"}
	}
	pos := inp.Pos
	inp.Next()
	return &ast.TextNode{Text: inp.Src[pos:inp.Pos]}
}

	}
	return nil, false
}

func (cp *zmkP) parseReference(closeCh rune) (ref string, ins ast.InlineSlice, ok bool) {
	inp := cp.inp
	inp.Next()
	for inp.Ch == ' ' {
		inp.Next()
	}
	hasSpace := false
	cp.skipSpace()
	pos := inp.Pos
	hasSpace, ok := cp.readReferenceToSep(closeCh)
loop:
	if !ok {
	for {
		switch inp.Ch {
		case input.EOS:
			return "", nil, false
		return "", nil, false
		case '\n', '\r', ' ':
			hasSpace = true
		case '|', closeCh:
			break loop
		}
		inp.Next()
	}
	if inp.Ch == '|' { // First part must be inline text
		if pos == inp.Pos { // [[| or {{|
			return "", nil, false
		}
		inp.SetPos(pos)
	loop1:
		for {
			switch inp.Ch {
			case input.EOS, '|':
				break loop1
			}
			in := cp.parseInline()
		ins = cp.parseReferenceInline()
			ins = append(ins, in)
		}
		inp.Next()
		pos = inp.Pos
	} else if hasSpace {
		return "", nil, false
	}

	inp.SetPos(pos)
	for inp.Ch == ' ' {
		inp.Next()
		pos = inp.Pos
	cp.skipSpace()
	pos = inp.Pos
	}
loop2:
	for {
		switch inp.Ch {
		case input.EOS, '\n', '\r', ' ':
			return "", nil, false
	if !cp.readReferenceToClose(closeCh) {
		return "", nil, false
		case closeCh:
			break loop2
		}
		inp.Next()
	}
	ref = inp.Src[pos:inp.Pos]
	inp.Next()
	if inp.Ch != closeCh {
		return "", nil, false
	}
	inp.Next()
	return ref, ins, true
}

func (cp *zmkP) readReferenceToSep(closeCh rune) (bool, bool) {
	hasSpace := false
	inp := cp.inp
	for {
		switch inp.Ch {
		case input.EOS:
			return false, false
		case '\n', '\r', ' ':
			hasSpace = true
		case '|', closeCh:
			return hasSpace, true
		}
		inp.Next()
	}
}

func (cp *zmkP) parseReferenceInline() (ins ast.InlineSlice) {
	for {
		switch cp.inp.Ch {
		case input.EOS, '|':
			return ins
		}
		in := cp.parseInline()
		ins = append(ins, in)
	}
}

func (cp *zmkP) readReferenceToClose(closeCh rune) bool {
	inp := cp.inp
	for {
		switch inp.Ch {
		case input.EOS, '\n', '\r', ' ':
			return false
		case closeCh:
			return true
		}
		inp.Next()
	}
}

func (cp *zmkP) parseCite() (*ast.CiteNode, bool) {
	inp := cp.inp
	inp.Next()
	switch inp.Ch {
	case ' ', ',', '|', ']', '\n', '\r':
		return nil, false

		return nil, false
	}
	attrs := cp.parseAttributes(false)
	return &ast.FootnoteNode{Inlines: ins, Attrs: attrs}, true
}

func (cp *zmkP) parseLinkLikeRest() (ast.InlineSlice, bool) {
	inp := cp.inp
	cp.skipSpace()
	for inp.Ch == ' ' {
		inp.Next()
	}
	var ins ast.InlineSlice
	inp := cp.inp
	for inp.Ch != ']' {
		in := cp.parseInline()
		if in == nil {
			return nil, false
		}
		ins = append(ins, in)
		if _, ok := in.(*ast.BreakNode); ok {
		if _, ok := in.(*ast.BreakNode); ok && input.IsEOLEOS(inp.Ch) {
			ch := cp.inp.Ch
			switch ch {
			case input.EOS, '\n', '\r':
				return nil, false
			return nil, false
			}
		}
	}
	inp.Next()
	return ins, true
}

func (cp *zmkP) parseImage() (ast.InlineNode, bool) {

	inp.Next()
	if inp.Ch != '%' {
		return nil, false
	}
	for inp.Ch == '%' {
		inp.Next()
	}
	for inp.Ch == ' ' {
		inp.Next()
	cp.skipSpace()
	}
	pos := inp.Pos
	for {
		switch inp.Ch {
		case input.EOS, '\n', '\r':
		if input.IsEOLEOS(inp.Ch) {
			return &ast.LiteralNode{Code: ast.LiteralComment, Text: inp.Src[pos:inp.Pos]}, true
		}
		inp.Next()
	}
}

var mapRuneFormat = map[rune]ast.FormatCode{

	if !ok {
		panic(fmt.Sprintf("%q is not a formatting char", fch))
	}
	inp.Next() // read 2nd formatting character
	if inp.Ch != fch {
		return nil, false
	}
	fn := &ast.FormatNode{Code: code}
	inp.Next()
	fn := &ast.FormatNode{Code: code}
	for {
		if inp.Ch == input.EOS {
			return nil, false
		}
		if inp.Ch == fch {
			inp.Next()
			if inp.Ch == fch {
				inp.Next()
				fn.Attrs = cp.parseAttributes(false)
				return fn, true
			}
			fn.Inlines = append(fn.Inlines, &ast.TextNode{Text: string(fch)})
		} else if in := cp.parseInline(); in != nil {
			if _, ok := in.(*ast.BreakNode); ok {
			if _, ok := in.(*ast.BreakNode); ok && input.IsEOLEOS(inp.Ch) {
				switch inp.Ch {
				case input.EOS, '\n', '\r':
					return nil, false
				return nil, false
				}
			}
			fn.Inlines = append(fn.Inlines, in)
		}
	}
}

var mapRuneLiteral = map[rune]ast.LiteralCode{

		}
	}
}

// VisitTable post-processes a table.
func (pp *postProcessor) VisitTable(tn *ast.TableNode) {
	width := tableWidth(tn)
	tn.Align = make([]ast.Alignment, 0, width)
	tn.Align = make([]ast.Alignment, width)
	for i := 0; i < width; i++ {
		tn.Align = append(tn.Align, ast.AlignDefault)
		tn.Align[i] = ast.AlignDefault
	}
	if len(tn.Rows) > 0 && isHeaderRow(tn.Rows[0]) {
		tn.Header = tn.Rows[0]
		tn.Rows = tn.Rows[1:]
		for pos, cell := range tn.Header {
		pp.visitTableHeader(tn)
			if inlines := cell.Inlines; len(inlines) > 0 {
				if textNode, ok := inlines[0].(*ast.TextNode); ok {
					textNode.Text = strings.TrimPrefix(textNode.Text, "=")
				}
				if textNode, ok := inlines[len(inlines)-1].(*ast.TextNode); ok {
					if tnl := len(textNode.Text); tnl > 0 {
						if align := getAlignment(textNode.Text[tnl-1]); align != ast.AlignDefault {
							tn.Align[pos] = align
							textNode.Text = textNode.Text[0 : tnl-1]
						}
					}
				}
			}
		}
	}
	if len(tn.Header) > 0 {
		tn.Header = appendCells(tn.Header, width, tn.Align)
		for i, cell := range tn.Header {
			pp.processCell(cell, tn.Align[i])
		}
	}
	pp.visitTableRows(tn, width)
}

func (pp *postProcessor) visitTableHeader(tn *ast.TableNode) {
	for pos, cell := range tn.Header {
		inlines := cell.Inlines
		if len(inlines) == 0 {
			continue
		}
		if textNode, ok := inlines[0].(*ast.TextNode); ok {
			textNode.Text = strings.TrimPrefix(textNode.Text, "=")
		}
		if textNode, ok := inlines[len(inlines)-1].(*ast.TextNode); ok {
			if tnl := len(textNode.Text); tnl > 0 {
				if align := getAlignment(textNode.Text[tnl-1]); align != ast.AlignDefault {
					tn.Align[pos] = align
					textNode.Text = textNode.Text[0 : tnl-1]
				}
			}
		}
	}
}

func (pp *postProcessor) visitTableRows(tn *ast.TableNode, width int) {
	for i, row := range tn.Rows {
		tn.Rows[i] = appendCells(row, width, tn.Align)
		row = tn.Rows[i]
		for i, cell := range row {
			pp.processCell(cell, tn.Align[i])
		}
	}

}

func tableWidth(tn *ast.TableNode) int {
	width := 0
	for _, row := range tn.Rows {
		if width < len(row) {
			width = len(row)

//
// Two text nodes are merged into one.
//
// Two spaces following a break are merged into a hard break.
func (pp *postProcessor) processInlineSliceCopy(ins ast.InlineSlice) int {
	maxPos := len(ins)
	for {
		again := false
		fromPos, toPos := 0, 0
		again, toPos := pp.processInlineSliceCopyLoop(ins, maxPos)
		for fromPos < maxPos {
			ins[toPos] = ins[fromPos]
			fromPos++
			switch in := ins[toPos].(type) {
			case *ast.TextNode:
				for fromPos < maxPos {
					if tn, ok := ins[fromPos].(*ast.TextNode); ok {
						in.Text = in.Text + tn.Text
						fromPos++
					} else {
						break
					}
				}
			case *ast.SpaceNode:
				if fromPos < maxPos {
					switch nn := ins[fromPos].(type) {
					case *ast.BreakNode:
						if len(in.Lexeme) > 1 {
							nn.Hard = true
							ins[toPos] = nn
							fromPos++
						}
					case *ast.TextNode:
						if pp.inVerse {
							ins[toPos] = &ast.TextNode{Text: strings.Repeat("\u00a0", len(in.Lexeme)) + nn.Text}
							fromPos++
							again = true
						}
					}
				}
			case *ast.BreakNode:
				if pp.inVerse {
					in.Hard = true
				}
			}
			toPos++
		}
		for pos := toPos; pos < maxPos; pos++ {
			ins[pos] = nil // Allow excess nodes to be garbage collected.
		}
		if !again {
			return toPos
		}
		maxPos = toPos
	}
}

func (pp *postProcessor) processInlineSliceCopyLoop(
	ins ast.InlineSlice, maxPos int) (bool, int) {

	again := false
	fromPos, toPos := 0, 0
	for fromPos < maxPos {
		ins[toPos] = ins[fromPos]
		fromPos++
		switch in := ins[toPos].(type) {
		case *ast.TextNode:
			for fromPos < maxPos {
				if tn, ok := ins[fromPos].(*ast.TextNode); ok {
					in.Text = in.Text + tn.Text
					fromPos++
				} else {
					break
				}
			}
		case *ast.SpaceNode:
			if fromPos < maxPos {
				switch nn := ins[fromPos].(type) {
				case *ast.BreakNode:
					if len(in.Lexeme) > 1 {
						nn.Hard = true
						ins[toPos] = nn
						fromPos++
					}
				case *ast.TextNode:
					if pp.inVerse {
						ins[toPos] = &ast.TextNode{Text: strings.Repeat("\u00a0", len(in.Lexeme)) + nn.Text}
						fromPos++
						again = true
					}
				}
			}
		case *ast.BreakNode:
			if pp.inVerse {
				in.Hard = true
			}
		}
		toPos++
	}
	return again, toPos
}

// processInlineSliceTail removes empty text nodes, breaks and spaces at the end.
func (pp *postProcessor) processInlineSliceTail(ins ast.InlineSlice, toPos int) int {
	for toPos > 0 {
		switch n := ins[toPos-1].(type) {
		case *ast.TextNode:
			if len(n.Text) > 0 {

		return false
	}
	key := string(inp.Src[posK:inp.Pos])
	if inp.Ch != '=' {
		attrs[key] = ""
		return true
	}
	if sameLine {
	if sameLine && input.IsEOLEOS(inp.Ch) {
		switch inp.Ch {
		case input.EOS, '\n', '\r':
			return false
		return false
		}
	}
	return cp.parseAttributeValue(key, attrs, sameLine)
}

func (cp *zmkP) parseAttributeValue(
	key string, attrs map[string]string, sameLine bool) bool {
	inp := cp.inp
	inp.Next()
	if inp.Ch == '"' {
		inp.Next()
		var val string
		for {
			switch inp.Ch {
			case input.EOS:
				return false
		return cp.parseQuotedAttributeValue(key, attrs, sameLine)
			case '"':
				updateAttrs(attrs, key, val)
				inp.Next()
				return true
			case '\n', '\r':
				if sameLine {
					return false
				}
				inp.EatEOL()
				val += " "
			case '\\':
				inp.Next()
				switch inp.Ch {
				case input.EOS, '\n', '\r':
					return false
				}
				fallthrough
			default:
				val += string(inp.Ch)
				inp.Next()
			}
		}
	}
	posV := inp.Pos
	for {
		switch inp.Ch {
		case input.EOS:
			return false
		case '\n', '\r':
			if sameLine {
				return false
			}
			fallthrough
		case ' ', '}':
			updateAttrs(attrs, key, inp.Src[posV:inp.Pos])
			return true
		}
		inp.Next()
	}
}

func (cp *zmkP) parseQuotedAttributeValue(key string, attrs map[string]string, sameLine bool) bool {
	inp := cp.inp
	inp.Next()
	var val string
	for {
		switch inp.Ch {
		case input.EOS:
			return false
		case '"':
			updateAttrs(attrs, key, val)
			inp.Next()
			return true
		case '\n', '\r':
			if sameLine {
				return false
			}
			inp.EatEOL()
			val += " "
		case '\\':
			inp.Next()
			switch inp.Ch {
			case input.EOS, '\n', '\r':
				return false
			}
			fallthrough
		default:
			val += string(inp.Ch)
			inp.Next()
		}
	}

}

func updateAttrs(attrs map[string]string, key, val string) {
	if prevVal := attrs[key]; len(prevVal) > 0 {
		attrs[key] = prevVal + " " + val
	} else {
		attrs[key] = val

			inp.Next()
		}
		if pos < inp.Pos {
			return &ast.Attributes{Attrs: map[string]string{"": inp.Src[pos:inp.Pos]}}
		}

		// No immediate name: skip spaces
		cp.skipSpace(!sameLine)
		cp.skipSpace()
	}

	pos := inp.Pos
	attrs, success := cp.doParseAttributes(sameLine)
	if sameLine || success {
		return attrs
	}
	inp.SetPos(pos)
	return nil
}

func (cp *zmkP) doParseAttributes(sameLine bool) (res *ast.Attributes, success bool) {
	inp := cp.inp
	if inp.Ch != '{' {
		return nil, false
	}
	inp.Next()
	attrs := map[string]string{}
	if !cp.parseAttributeValues(sameLine, attrs) {
		return nil, false
	}
	inp.Next()
	return &ast.Attributes{Attrs: attrs}, true
}
loop:

func (cp *zmkP) parseAttributeValues(sameLine bool, attrs map[string]string) bool {
	inp := cp.inp
	for {
		cp.skipSpace(!sameLine)
		cp.skipSpaceLine(sameLine)
		switch inp.Ch {
		case input.EOS:
			return nil, false
			return false
		case '}':
			break loop
			return true
		case '.':
			inp.Next()
			posC := inp.Pos
			for isNameRune(inp.Ch) {
				inp.Next()
			}
			if posC == inp.Pos {
				return nil, false
				return false
			}
			updateAttrs(attrs, "class", inp.Src[posC:inp.Pos])
		case '=':
			delete(attrs, "")
			if !cp.parseAttributeValue("", attrs, sameLine) {
				return nil, false
				return false
			}
		default:
			if !cp.parseNormalAttribute(attrs, sameLine) {
				return nil, false
				return false
			}
		}

		switch inp.Ch {
		case '}':
			break loop
			return true
		case '\n', '\r':
			if sameLine {
				return nil, false
				return false
			}
		case ' ', ',':
			inp.Next()
		default:
			return nil, false
			return false
		}
	}
	inp.Next()
	return &ast.Attributes{Attrs: attrs}, true
}

func (cp *zmkP) skipSpace(eolIsSpace bool) {
	inp := cp.inp
	if eolIsSpace {
		for {
			switch inp.Ch {
			case ' ':
				inp.Next()
			case '\n', '\r':
				inp.EatEOL()
			default:
				return
			}
		}
	}
	for inp.Ch == ' ' {
func (cp *zmkP) skipSpaceLine(sameLine bool) {
	if sameLine {
		cp.skipSpace()
		return
	}
	for inp := cp.inp; ; {
		switch inp.Ch {
		case ' ':
			inp.Next()
		case '\n', '\r':
			inp.EatEOL()
		default:
			return
		}
	}
}

func (cp *zmkP) skipSpace() {
	for inp := cp.inp; inp.Ch == ' '; {
		inp.Next()
	}
}

func isNameRune(ch rune) bool {
	return unicode.IsLetter(ch) || unicode.IsDigit(ch) || ch == '-' || ch == '_'
}

	"strings"
	"testing"

	"zettelstore.de/z/ast"
	"zettelstore.de/z/domain/meta"
	"zettelstore.de/z/input"
	"zettelstore.de/z/parser"

	// Ensure that the text encoder is available.
	// Needed by parser/cleanup.go
	_ "zettelstore.de/z/encoder/textenc"
)

type TestCase struct{ source, want string }
type TestCases []TestCase

func replace(s string, tcs TestCases) TestCases {
	var testCases TestCases

//-----------------------------------------------------------------------------
// Copyright (c) 2021 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.
//-----------------------------------------------------------------------------

// Package change provides definition for place changes.
package change

import (
	"zettelstore.de/z/domain/id"
)

// Reason gives an indication, why the ObserverFunc was called.
type Reason int

// Values for Reason
const (
	_        Reason = iota
	OnReload        // Place was reloaded
	OnUpdate        // A zettel was created or changed
	OnDelete        // A zettel was removed
)

// Info contains all the data about a changed zettel.
type Info struct {
	Reason Reason
	Zid    id.Zid
}

// Func is a function to be called when a change is detected.
type Func func(Info)

// Subject is a place 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(Func)
}