Zettelstore

0.15.0

func (pp *polBox) Refresh(ctx context.Context) error {
	user := server.GetUser(ctx)
	if pp.policy.CanRefresh(user) {
		return pp.box.Refresh(ctx)
	}
	return box.NewErrNotAllowed("Refresh", user, id.Invalid)
}
func (pp *polBox) ReIndex(ctx context.Context, zid id.Zid) error {
	user := server.GetUser(ctx)
	if pp.policy.CanRefresh(user) {
		// If a user is allowed to refresh all data, it it also allowed to re-index a zettel.
		return pp.box.ReIndex(ctx, zid)
	}
	return box.NewErrNotAllowed("ReIndex", user, zid)
}

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








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







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

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

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

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

// WriteBox is a box that can create / update zettel content.
type WriteBox interface {
	// CanCreateZettel returns true, if box could possibly create a new zettel.
	CanCreateZettel(ctx context.Context) bool

	// CreateZettel creates a new zettel.
	// Returns the new zettel id (and an error indication).
	CreateZettel(ctx context.Context, zettel zettel.Zettel) (id.Zid, error)

	// CanUpdateZettel returns true, if box could possibly update the given zettel.
	CanUpdateZettel(ctx context.Context, zettel zettel.Zettel) bool

	// UpdateZettel updates an existing zettel.
	UpdateZettel(ctx context.Context, zettel zettel.Zettel) error
}

// ZidFunc is a function that processes identifier of a zettel.
type ZidFunc func(id.Zid)

// MetaFunc is a function that processes metadata of a zettel.
type MetaFunc func(*meta.Meta)

	// Refresh the box data.
	Refresh(context.Context)
}

// Box is to be used outside the box package and its descendants.
type Box interface {
	BaseBox
	WriteBox

	// FetchZids returns the set of all zettel identifer managed by the box.
	FetchZids(ctx context.Context) (id.Set, error)

	// GetMeta returns the metadata of the zettel with the given identifier.
	GetMeta(context.Context, id.Zid) (*meta.Meta, error)

	// SelectMeta returns a list of metadata that comply to the given selection criteria.
	// If `metaSeq` is `nil`, the box assumes metadata of all available zettel.
	SelectMeta(ctx context.Context, metaSeq []*meta.Meta, q *query.Query) ([]*meta.Meta, error)

	// GetAllZettel retrieves a specific zettel from all managed boxes.
	GetAllZettel(ctx context.Context, zid id.Zid) ([]zettel.Zettel, error)

	// Refresh the data from the box and from its managed sub-boxes.
	Refresh(context.Context) error

	// ReIndex one zettel to update its index data.
	ReIndex(context.Context, id.Zid) error
}

// Stats record stattistics about a box.
type Stats struct {
	// ReadOnly indicates that boxes cannot be modified.
	ReadOnly bool

var ErrReadOnly = errors.New("read-only box")

// ErrZettelNotFound is returned if a zettel was not found in the box.
type ErrZettelNotFound struct{ Zid id.Zid }

func (eznf ErrZettelNotFound) Error() string { return "zettel not found: " + eznf.Zid.String() }



// ErrConflict is returned if a box operation detected a conflict..
// One example: if calculating a new zettel identifier takes too long.
var ErrConflict = errors.New("conflict")

// ErrCapacity is returned if a box has reached its capacity.
var ErrCapacity = errors.New("capacity exceeded")

// ErrInvalidZid is returned if the zettel id is not appropriate for the box operation.
type ErrInvalidZid struct{ Zid string }

func (err ErrInvalidZid) Error() string { return "invalid Zettel id: " + err.Zid }

}

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

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








func (cb *compBox) GetZettel(_ context.Context, zid id.Zid) (zettel.Zettel, error) {
	if gen, ok := myZettel[zid]; ok && gen.meta != nil {
		if m := gen.meta(zid); m != nil {
			updateMeta(m)
			if genContent := gen.content; genContent != nil {
				cb.log.Trace().Msg("GetZettel/Content")
				return zettel.Zettel{

				handle(m)
			}
		}
	}
	return nil
}








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

func (cb *compBox) RenameZettel(_ context.Context, curZid, _ id.Zid) (err error) {
	if _, ok := myZettel[curZid]; ok {

	number   int
	zettel   map[id.Zid]constZettel
	enricher box.Enricher
}

func (*constBox) Location() string { return "const:" }








func (cb *constBox) GetZettel(_ context.Context, zid id.Zid) (zettel.Zettel, error) {
	if z, ok := cb.zettel[zid]; ok {
		cb.log.Trace().Msg("GetZettel")
		return zettel.Zettel{Meta: meta.NewWithData(zid, z.header), Content: z.content}, nil
	}
	err := box.ErrZettelNotFound{Zid: zid}
	cb.log.Trace().Err(err).Msg("GetZettel/Err")

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








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

func (cb *constBox) RenameZettel(_ context.Context, curZid, _ id.Zid) (err error) {
	if _, ok := cb.zettel[curZid]; ok {

		zettel.NewContent(contentZettelSxn)},
	id.InfoTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Info HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20200804111624",
			api.KeyModified:   "20231023152000",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentInfoSxn)},
	id.FormTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Form HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,

		zettel.NewContent(contentDeleteSxn)},
	id.ListTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore List Zettel HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20230704122100",
			api.KeyModified:   "20231002120600",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentListZettelSxn)},
	id.ErrorTemplateZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Error HTML Template",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20210305133215",
			api.KeyModified:   "20230527224800",
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentErrorSxn)},
	id.StartSxnZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Sxn Start Code",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20230824160700",
			api.KeyVisibility: api.ValueVisibilityExpert,
			api.KeyPrecursor:  string(api.ZidSxnBase),
		},
		zettel.NewContent(contentStartCodeSxn)},
	id.BaseSxnZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Sxn Base Code",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20230619132800",
			api.KeyModified:   "20231012154500",
			api.KeyReadOnly:   api.ValueTrue,
			api.KeyVisibility: api.ValueVisibilityExpert,
			api.KeyPrecursor:  string(api.ZidSxnPrelude),
		},
		zettel.NewContent(contentBaseCodeSxn)},
	id.PreludeSxnZid: {
		constHeader{
			api.KeyTitle:      "Zettelstore Sxn Prelude",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxSxn,
			api.KeyCreated:    "20231006181700",
			api.KeyModified:   "20231019140400",
			api.KeyReadOnly:   api.ValueTrue,
			api.KeyVisibility: api.ValueVisibilityExpert,
		},
		zettel.NewContent(contentPreludeSxn)},
	id.MustParse(api.ZidBaseCSS): {
		constHeader{
			api.KeyTitle:      "Zettelstore Base CSS",
			api.KeyRole:       api.ValueRoleConfiguration,
			api.KeySyntax:     meta.SyntaxCSS,
			api.KeyCreated:    "20200804111624",
			api.KeyVisibility: api.ValueVisibilityPublic,

			api.KeyLang:       api.ValueLangEN,
			api.KeyCreated:    "20210217161829",
			api.KeyVisibility: api.ValueVisibilityCreator,
		},
		zettel.NewContent(contentNewTOCZettel)},
	id.MustParse(api.ZidTemplateNewZettel): {
		constHeader{
			api.KeyTitle:                 "New Zettel",
			api.KeyRole:                  api.ValueRoleConfiguration,
			api.KeySyntax:                meta.SyntaxZmk,
			api.KeyCreated:               "20201028185209",
			api.KeyModified:              "20230929132900",
			meta.NewPrefix + api.KeyRole: api.ValueRoleZettel,
			api.KeyVisibility:            api.ValueVisibilityCreator,
		},
		zettel.NewContent(nil)},
	id.MustParse(api.ZidTemplateNewTag): {
		constHeader{
			api.KeyTitle:                  "New Tag",
			api.KeyRole:                   api.ValueRoleConfiguration,
			api.KeySyntax:                 meta.SyntaxZmk,
			api.KeyCreated:                "20230929132400",
			meta.NewPrefix + api.KeyRole:  api.ValueRoleTag,
			meta.NewPrefix + api.KeyTitle: "#",
			api.KeyVisibility:             api.ValueVisibilityCreator,
		},
		zettel.NewContent(nil)},
	id.MustParse(api.ZidTemplateNewUser): {
		constHeader{
			api.KeyTitle:                       "New User",
			api.KeyRole:                        api.ValueRoleConfiguration,
			api.KeySyntax:                      meta.SyntaxNone,

//go:embed start.sxn
var contentStartCodeSxn []byte

//go:embed wuicode.sxn
var contentBaseCodeSxn []byte

//go:embed prelude.sxn
var contentPreludeSxn []byte

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

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

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

//go:embed home.zettel
var contentHomeZettel []byte

`(article
  (header (h1 "Information for Zettel " ,zid)
    (p
      (a (@ (href ,web-url)) "Web")
      (@H " · ") (a (@ (href ,context-url)) "Context")
      ,@(if (bound? 'edit-url) `((@H " · ") (a (@ (href ,edit-url)) "Edit")))
      ,@(ROLE-DEFAULT-actions (current-environment))
      ,@(if (bound? 'reindex-url) `((@H " · ") (a (@ (href ,reindex-url)) "Reindex")))
      ,@(if (bound? 'rename-url) `((@H " · ") (a (@ (href ,rename-url)) "Rename")))
      ,@(if (bound? 'delete-url) `((@H " · ") (a (@ (href ,delete-url)) "Delete")))
    )
  )
  (h2 "Interpreted Metadata")
  (table ,@(map wui-table-row metadata))
  (h2 "References")

`(article
  (header (h1 ,heading))
  (form (@ (action ,search-url))
    (input (@ (class "zs-input") (type "text") (placeholder "Search..") (name ,query-key-query) (value ,query-value) (dir "auto"))))
  ,@(if (bound? 'tag-zettel)
     `((p (@ (class "zs-tag-zettel")) "Tag zettel: " ,@tag-zettel))
    )
  ,@(if (bound? 'create-tag-zettel)
     `((p (@ (class "zs-tag-zettel")) "Create tag zettel: " ,@create-tag-zettel))
    )
  ,@content
  ,@endnotes
  (form (@ (action ,(if (bound? 'create-url) create-url)))
      "Other encodings: "
      (a (@ (href ,data-url)) "data")
      ", "
      (a (@ (href ,plain-url)) "plain")

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

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

;;; This zettel contains all sxn definitions that are independent of specific
;;; subsystems, such as WebUI, API, or other. It just contains generic code to
;;; be used elsewhere.

;; Constants NIL and T
(defconst NIL ())
(defconst T   'T)

;; Function not
(defun not (x) (if x NIL T))
(defconst not not)

;; let macro
;;
;; (let (BINDING ...) EXPR ...), where BINDING is a list of two elements
;;   (SYMBOL EXPR)
(defmacro let (bindings . body)
    `((lambda ,(map car bindings) ,@body) ,@(map cadr bindings)))

;; let* macro
;;
;; (let* (BINDING ...) EXPR ...), where SYMBOL may occur in later bindings.
(defmacro let* (bindings . body)
    (if (null? bindings)
        `((lambda () ,@body))
        `((lambda (,(caar bindings))
                  (let* ,(cdr bindings) ,@body))
                  ,(cadar bindings))))

;; and macro
;;
;; (and EXPR ...)
(defmacro and args
    (cond ((null? args)       T)
          ((null? (cdr args)) (car args))
          (T                  `(if ,(car args) (and ,@(cdr args))))))


;; or macro
;;
;; (or EXPR ...)
(defmacro or args
    (cond ((null? args)       NIL)
          ((null? (cdr args)) (car args))
          (T                  `(if ,(car args) T (or ,@(cdr args))))))

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

;; Contains WebUI specific code, but not related to a specific template.

;; wui-list-item returns the argument as a HTML list item.
(defun wui-item (s) `(li ,s))

;; wui-table-row takes a pair and translates it into a HTML table row with
;; two columns.
(defun wui-table-row (p)
    `(tr (td ,(car p)) (td ,(cdr p))))

;; wui-valid-link translates a local link into a HTML link. A link is a pair
;; (valid . url). If valid is not truish, only the invalid url is returned.
(defun wui-valid-link (l)
    (if (car l)
        `(li (a (@ (href ,(cdr l))) ,(cdr l)))
        `(li ,(cdr l))))

;; wui-link takes a link (title . url) and returns a HTML reference.
(defun wui-link (q)
    `(a (@ (href ,(cdr q))) ,(car q)))

;; wui-item-link taks a pair (text . url) and returns a HTML link inside
;; a list item.
(defun wui-item-link (q) `(li ,(wui-link q)))

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

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

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

;; wui-datalist returns a HTML datalist with the given HTML identifier and a
;; list of values.
(defun wui-datalist (id lst)
    (if lst
        `((datalist (@ (id ,id)) ,@(map wui-option-value lst)))))

;; wui-pair-desc-item takes a pair '(term . text) and returns a list with
;; a HTML description term and a HTML description data. 
(defun wui-pair-desc-item (p) `((dt ,(car p)) (dd ,(cdr p))))

;; wui-meta-desc returns a HTML description list made from the list of pairs
;; given.
(defun wui-meta-desc (l)
    `(dl ,@(apply append (map wui-pair-desc-item l))))

;; wui-enc-matrix returns the HTML table of all encodings and parts.
(defun wui-enc-matrix (matrix)
    `(table
      ,@(map
         (lambda (row) `(tr (th ,(car row)) ,@(map wui-tdata-link (cdr row))))
         matrix)))

;; CSS-ROLE-map is a mapping (pair list, assoc list) of role names to zettel
;; identifier. It is used in the base template to update the metadata of the
;; HTML page to include some role specific CSS code.
;; Referenced in function "ROLE-DEFAULT-meta".
(defvar CSS-ROLE-map '())

;; ROLE-DEFAULT-meta returns some metadata for the base template. Any role
;; specific code should include the returned list of this function.
(defun ROLE-DEFAULT-meta (env)
    `(,@(let* ((meta-role (environment-lookup 'meta-role env))
               (entry (assoc CSS-ROLE-map meta-role)))
              (if (pair? entry)
                  `((link (@ (rel "stylesheet") (href ,(zid-content-path (cdr entry))))))
              )

        )
    )
)

;;; ACTION-SEPARATOR defines a HTML value that separates actions links.
(defvar ACTION-SEPARATOR '(@H " · "))

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

;;; ROLE-tag-actions returns an additional action "Zettel" for zettel with role "tag".
(defun ROLE-tag-actions (env)
    `(,@(ROLE-DEFAULT-actions env)
      ,@(let ((title (environment-lookup 'title env)))
             (if (and (defined? title) title)
                 `(,ACTION-SEPARATOR (a (@ (href ,(query->url (string-append "tags:" title)))) "Zettel"))
             )
        )
    )
)

;;; ROLE-DEFAULT-heading returns the default text for headings, below the
;;; references of a zettel. In most cases it should be called from an
;;; overwriting function.
(defun ROLE-DEFAULT-heading (env)
    `(,@(let ((meta-url (environment-lookup 'meta-url env)))
           (if (defined? meta-url) `((br) "URL: " ,(url-to-html meta-url))))
      ,@(let ((meta-author (environment-lookup 'meta-author env)))
           (if (and (defined? meta-author) meta-author) `((br) "By " ,meta-author)))
    )
)

}

func (zb *zipBox) Stop(context.Context) {
	zb.dirSrv.Stop()
	zb.dirSrv = nil
}









func (zb *zipBox) GetZettel(_ context.Context, zid id.Zid) (zettel.Zettel, error) {
	entry := zb.dirSrv.GetDirEntry(zid)
	if !entry.IsValid() {
		return zettel.Zettel{}, box.ErrZettelNotFound{Zid: zid}
	}
	reader, err := zip.OpenReader(zb.name)
	if err != nil {

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









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

func (zb *zipBox) RenameZettel(_ context.Context, curZid, newZid id.Zid) error {
	err := box.ErrReadOnly

		sb.WriteString(mgr.boxes[i].Location())
	}
	return sb.String()
}

// CanCreateZettel returns true, if box could possibly create a new zettel.
func (mgr *Manager) CanCreateZettel(ctx context.Context) bool {
	if mgr.State() != box.StartStateStarted {
		return false
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	if box, isWriteBox := mgr.boxes[0].(box.WriteBox); isWriteBox {
		return box.CanCreateZettel(ctx)
	}
	return false
}

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

// GetZettel retrieves a specific zettel.
func (mgr *Manager) GetZettel(ctx context.Context, zid id.Zid) (zettel.Zettel, error) {
	mgr.mgrLog.Debug().Zid(zid).Msg("GetZettel")
	if mgr.State() != box.StartStateStarted {
		return zettel.Zettel{}, box.ErrStopped

	result = compSearch.AfterSearch(result)
	mgr.mgrLog.Trace().Int("count", int64(len(result))).Msg("found with ApplyMeta")
	return result, nil
}

// CanUpdateZettel returns true, if box could possibly update the given zettel.
func (mgr *Manager) CanUpdateZettel(ctx context.Context, zettel zettel.Zettel) bool {
	if mgr.State() != box.StartStateStarted {
		return false
	}
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	if box, isWriteBox := mgr.boxes[0].(box.WriteBox); isWriteBox {
		return box.CanUpdateZettel(ctx, zettel)
	}
	return false

}

// UpdateZettel updates an existing zettel.
func (mgr *Manager) UpdateZettel(ctx context.Context, zettel zettel.Zettel) error {
	mgr.mgrLog.Debug().Zid(zettel.Meta.Zid).Msg("UpdateZettel")
	if mgr.State() != box.StartStateStarted {
		return box.ErrStopped
	}
	if box, isWriteBox := mgr.boxes[0].(box.WriteBox); isWriteBox {
		zettel.Meta = mgr.cleanMetaProperties(zettel.Meta)
		if err := box.UpdateZettel(ctx, zettel); err != nil {

			return err
		}
		mgr.idxUpdateZettel(ctx, zettel)
		return nil
	}
	return box.ErrReadOnly
}

// AllowRenameZettel returns true, if box will not disallow renaming the zettel.
func (mgr *Manager) AllowRenameZettel(ctx context.Context, zid id.Zid) bool {
	if mgr.State() != box.StartStateStarted {
		return false
	}

		if err != nil && !errors.As(err, &errZNF) {
			for j := 0; j < i; j++ {
				mgr.boxes[j].RenameZettel(ctx, newZid, curZid)
			}
			return err
		}
	}
	mgr.idxRenameZettel(ctx, curZid, newZid)
	return nil
}

// CanDeleteZettel returns true, if box could possibly delete the given zettel.
func (mgr *Manager) CanDeleteZettel(ctx context.Context, zid id.Zid) bool {
	if mgr.State() != box.StartStateStarted {
		return false

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

// Remove all (computed) properties from metadata before storing the zettel.
func (mgr *Manager) cleanMetaProperties(m *meta.Meta) *meta.Meta {
	result := m.Clone()
	for _, p := range result.ComputedPairsRest() {
		if mgr.propertyKeys.Has(p.Key) {
			result.Delete(p.Key)
		}
	}
	return result
}

			zettel, err := mgr.GetZettel(ctx, zid)
			if err != nil {
				// Zettel was deleted or is not accessible b/c of other reasons
				mgr.idxLog.Trace().Zid(zid).Msg("delete")
				mgr.idxMx.Lock()
				mgr.idxSinceReload++
				mgr.idxMx.Unlock()
				mgr.idxDeleteZettel(ctx, zid)
				continue
			}
			mgr.idxLog.Trace().Zid(zid).Msg("update")
			mgr.idxMx.Lock()
			if arRoomNum == roomNum {
				mgr.idxDurReload = time.Since(start)
			}

	if inverseKey == "" {
		zi.AddBackRef(zid)
		return
	}
	zi.AddInverseRef(inverseKey, zid)
}

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

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

func (mgr *Manager) idxCheckZettel(s id.Set) {
	for zid := range s {
		mgr.idxAr.EnqueueZettel(zid)
	}
}

// Refresh internal box data.
func (mgr *Manager) Refresh(ctx context.Context) error {
	mgr.mgrLog.Debug().Msg("Refresh")
	if mgr.State() != box.StartStateStarted {
		return box.ErrStopped
	}
	mgr.infos <- box.UpdateInfo{Reason: box.OnReload, Zid: id.Invalid}
	mgr.mgrMx.Lock()
	defer mgr.mgrMx.Unlock()

	for _, bx := range mgr.boxes {
		if rb, ok := bx.(box.Refresher); ok {
			rb.Refresh(ctx)
		}
	}
	return nil
}

// ReIndex data of the given zettel.
func (mgr *Manager) ReIndex(_ context.Context, zid id.Zid) error {
	mgr.mgrLog.Debug().Msg("ReIndex")
	if mgr.State() != box.StartStateStarted {
		return box.ErrStopped
	}
	mgr.infos <- box.UpdateInfo{Reason: box.OnReload, Zid: zid}
	return nil
}

// ReadStats populates st with box statistics.
func (mgr *Manager) ReadStats(st *box.Stats) {
	mgr.mgrLog.Debug().Msg("ReadStats")
	mgr.mgrMx.RLock()
	defer mgr.mgrMx.RUnlock()
	subStats := make([]box.ManagedBoxStats, len(mgr.boxes))

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

type zettelData struct {
	meta      *meta.Meta // a local copy of the metadata, without computed keys
	dead      id.Slice   // list of dead references in this zettel
	forward   id.Slice   // list of forward references in this zettel
	backward  id.Slice   // list of zettel that reference with zettel
	otherRefs map[string]bidiRefs
	words     []string // list of words of this zettel
	urls      []string // list of urls of this zettel
}

type stringRefs map[string]id.Slice

type memStore struct {
	mx     sync.RWMutex
	intern map[string]string // map to intern strings

	zi.meta = m
	ms.updateDeadReferences(zidx, zi)
	ids := ms.updateForwardBackwardReferences(zidx, zi)
	toCheck = toCheck.Copy(ids)
	ids = ms.updateMetadataReferences(zidx, zi)
	toCheck = toCheck.Copy(ids)
	zi.words = updateStrings(zidx.Zid, ms.words, zi.words, zidx.GetWords())
	zi.urls = updateStrings(zidx.Zid, ms.urls, zi.urls, zidx.GetUrls())

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

	return toCheck

			}
		}
		ms.removeInverseMeta(zidx.Zid, key, remRefs)
	}
	return toCheck
}

func updateStrings(zid id.Zid, srefs stringRefs, prev []string, next store.WordSet) []string {
	newWords, removeWords := next.Diff(prev)
	for _, word := range newWords {
		if refs, ok := srefs[word]; ok {
			srefs[word] = addRef(refs, zid)
			continue
		}
		srefs[word] = id.Slice{zid}

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

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

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

	ms.idx[newZid] = newZi
	toCheck := ms.doDeleteZettel(curZid)
	toCheck = toCheck.CopySlice(ms.dead[newZid])
	delete(ms.dead, newZid)
	toCheck = toCheck.Add(newZid) // should update otherRefs
	return toCheck
}
func copyMeta(m *meta.Meta, newZid id.Zid) *meta.Meta {
	result := m.Clone()
	result.Zid = newZid
	return result
}
func (ms *memStore) copyDeadReferences(curDead id.Slice) id.Slice {
	// Must only be called if ms.mx is write-locked!
	if l := len(curDead); l > 0 {
		result := make(id.Slice, l)
		for i, ref := range curDead {
			result[i] = ref
			ms.dead[ref] = addRef(ms.dead[ref], ref)
		}
		return result
	}
	return nil
}
func (ms *memStore) copyForward(curForward id.Slice, newZid id.Zid) id.Slice {
	// Must only be called if ms.mx is write-locked!
	if l := len(curForward); l > 0 {
		result := make(id.Slice, l)
		for i, ref := range curForward {
			result[i] = ref
			if fzi, found := ms.idx[ref]; found {
				fzi.backward = addRef(fzi.backward, newZid)
			}
		}
		return result
	}
	return nil
}
func copyStrings(msStringMap stringRefs, curStrings []string, newZid id.Zid) []string {
	// Must only be called if ms.mx is write-locked!
	if l := len(curStrings); l > 0 {
		result := make([]string, l)
		for i, s := range curStrings {
			result[i] = s
			msStringMap[s] = addRef(msStringMap[s], newZid)
		}
		return result
	}
	return nil
}

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

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

	ms.deleteDeadSources(zid, zi)
	toCheck := ms.deleteForwardBackward(zid, zi)

	for key, mrefs := range zi.otherRefs {
		ms.removeInverseMeta(zid, key, mrefs.forward)
	}

	deleteStrings(ms.words, zi.words, zid)
	deleteStrings(ms.urls, zi.urls, zid)
	delete(ms.idx, zid)
	return toCheck
}

func (ms *memStore) deleteDeadSources(zid id.Zid, zi *zettelData) {
	// Must only be called if ms.mx is write-locked!
	for _, ref := range zi.dead {
		if drefs, ok := ms.dead[ref]; ok {
			drefs = remRef(drefs, zid)
			if len(drefs) > 0 {
				ms.dead[ref] = drefs
			} else {
				delete(ms.dead, ref)
			}
		}
	}
}

func (ms *memStore) deleteForwardBackward(zid id.Zid, zi *zettelData) id.Set {
	// Must only be called if ms.mx is write-locked!

	for _, ref := range zi.forward {
		if fzi, ok := ms.idx[ref]; ok {
			fzi.backward = remRef(fzi.backward, zid)
		}
	}
	var toCheck id.Set
	for _, ref := range zi.backward {
		if bzi, ok := ms.idx[ref]; ok {
			bzi.forward = remRef(bzi.forward, zid)



			toCheck = toCheck.Add(ref)
		}
	}
	return toCheck
}

func (ms *memStore) removeInverseMeta(zid id.Zid, key string, forward id.Slice) {
	// Must only be called if ms.mx is write-locked!

			if len(bzi.otherRefs) == 0 {
				bzi.otherRefs = nil
			}
		}
	}
}

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

func (ms *memStore) ReadStats(st *store.Stats) {
	ms.mx.RLock()
	st.Zettel = len(ms.idx)
	st.Words = uint64(len(ms.words))

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

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

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

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

	// ReadStats populates st with store statistics.
	ReadStats(st *Stats)

	// Dump the content to a Writer.
	Dump(io.Writer)
}

	ucCreateZettel := usecase.NewCreateZettel(logUc, rtConfig, protectedBoxManager)
	ucGetAllZettel := usecase.NewGetAllZettel(protectedBoxManager)
	ucGetZettel := usecase.NewGetZettel(protectedBoxManager)
	ucParseZettel := usecase.NewParseZettel(rtConfig, ucGetZettel)
	ucQuery := usecase.NewQuery(protectedBoxManager)
	ucEvaluate := usecase.NewEvaluate(rtConfig, &ucGetZettel, &ucQuery)
	ucQuery.SetEvaluate(&ucEvaluate)
	ucTagZettel := usecase.NewTagZettel(protectedBoxManager, &ucQuery)
	ucListSyntax := usecase.NewListSyntax(protectedBoxManager)
	ucListRoles := usecase.NewListRoles(protectedBoxManager)
	ucDelete := usecase.NewDeleteZettel(logUc, protectedBoxManager)
	ucUpdate := usecase.NewUpdateZettel(logUc, protectedBoxManager)
	ucRename := usecase.NewRenameZettel(logUc, protectedBoxManager)
	ucRefresh := usecase.NewRefresh(logUc, protectedBoxManager)
	ucReIndex := usecase.NewReIndex(logUc, protectedBoxManager)
	ucVersion := usecase.NewVersion(kernel.Main.GetConfig(kernel.CoreService, kernel.CoreVersion).(string))

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

		webSrv.AddZettelRoute('c', server.MethodPost, wui.MakePostCreateZettelHandler(&ucCreateZettel))
		webSrv.AddZettelRoute('d', server.MethodGet, wui.MakeGetDeleteZettelHandler(ucGetZettel, ucGetAllZettel))
		webSrv.AddZettelRoute('d', server.MethodPost, wui.MakePostDeleteZettelHandler(&ucDelete))
		webSrv.AddZettelRoute('e', server.MethodGet, wui.MakeEditGetZettelHandler(ucGetZettel, ucListRoles, ucListSyntax))
		webSrv.AddZettelRoute('e', server.MethodPost, wui.MakeEditSetZettelHandler(&ucUpdate))
	}
	webSrv.AddListRoute('g', server.MethodGet, wui.MakeGetGoActionHandler(&ucRefresh))
	webSrv.AddListRoute('h', server.MethodGet, wui.MakeListHTMLMetaHandler(&ucQuery, &ucTagZettel, &ucReIndex))
	webSrv.AddZettelRoute('h', server.MethodGet, wui.MakeGetHTMLZettelHandler(&ucEvaluate, ucGetZettel))
	webSrv.AddListRoute('i', server.MethodGet, wui.MakeGetLoginOutHandler())
	webSrv.AddListRoute('i', server.MethodPost, wui.MakePostLoginHandler(&ucAuthenticate))
	webSrv.AddZettelRoute('i', server.MethodGet, wui.MakeGetInfoHandler(
		ucParseZettel, &ucEvaluate, ucGetZettel, ucGetAllZettel, &ucQuery))

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

id: 00001000000000
title: Zettelstore Manual
role: manual
tags: #manual #zettelstore
syntax: zmk
created: 00010101000000
modified: 20231002143058

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

Version: {{00001000000001}}.

Licensed under the EUPL-1.2-or-later.

id: 00001000000001
title: Manual Version
role: configuration
syntax: zmk
created: 20231002142915
modified: 20231002142948

To be set by build tool.

id: 00001005090000
title: List of predefined zettel
role: manual
tags: #manual #reference #zettelstore
syntax: zmk
created: 20210126175322
modified: 20231002104819

The following table lists all predefined zettel with their purpose.

|= Identifier :|= Title | Purpose
| [[00000000000001]] | Zettelstore Version | Contains the version string of the running Zettelstore
| [[00000000000002]] | Zettelstore Host | Contains the name of the computer running the Zettelstore
| [[00000000000003]] | Zettelstore Operating System | Contains the operating system and CPU architecture of the computer running the Zettelstore

| [[00000000010700]] | Zettelstore Error HTML Template | View to show an error message
| [[00000000019000]] | Zettelstore Sxn Start Code | Starting point of sxn functions to build the templates
| [[00000000019990]] | Zettelstore Sxn Base Code | Base sxn functions to build the templates
| [[00000000020001]] | Zettelstore Base CSS | System-defined CSS file that is included by the [[Base HTML Template|00000000010100]]
| [[00000000025001]] | Zettelstore User CSS | User-defined CSS file that is included by the [[Base HTML Template|00000000010100]]
| [[00000000040001]] | Generic Emoji | Image that is shown if [[original image reference|00001007040322]] is invalid
| [[00000000090000]] | New Menu | Contains items that should contain in the zettel template menu
| [[00000000090001]] | New Zettel | Template for a new zettel with role ""[[zettel|00001006020100#zettel]]""
| [[00000000090002]] | New User | Template for a new [[user zettel|00001010040200]]
| [[00000000090003]] | New Tag | Template for a new [[tag zettel|00001006020100#tag]]
| [[00010000000000]] | Home | Default home zettel, contains some welcome information

If a zettel is not linked, it is not accessible for the current user.

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

id: 00001007031140
title: Zettelmarkup: Query Transclusion
role: manual
tags: #manual #search #zettelmarkup #zettelstore
syntax: zmk
created: 20220809132350
modified: 20231023163751

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

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

: Transform the zettel list into an [[Atom 1.0|https://www.rfc-editor.org/rfc/rfc4287]]-conformant document / feed.
  The document is embedded into the referencing zettel.
; ''RSS'' (aggregate)
: Transform the zettel list into a [[RSS 2.0|https://www.rssboard.org/rss-specification]]-conformant document / feed.
  The document is embedded into the referencing zettel.
; ''KEYS'' (aggregate)
: Emit a list of all metadata keys, together with the number of zettel having the key.
; ''REINDEX'' (aggregate)
: Will be ignored.
  This action may have been copied from an existing [[API query call|00001012051400]] (or from a WebUI query), but is here superfluous (and possibly harmful).
; Any [[metadata key|00001006020000]] of type [[Word|00001006035500]], [[WordSet|00001006036000]], or [[TagSet|00001006034000]] (aggregates)
: Emit an aggregate of the given metadata key.
  The key can be given in any letter case[^Except if the key name collides with one of the above names. In this case use at least one lower case letter.].

Example:
```zmk
{{{query:tags:#search | tags}}}
```
This is a tag cloud of all tags that are used together with the tag #search:
:::example
{{{query:tags:#search | tags}}}
:::

id: 00001007702000
title: Search term
role: manual
tags: #manual #search #zettelstore
syntax: zmk
created: 20220805150154
modified: 20230925173539

A search term allows you to specify one search restriction.
The result [[search expression|00001007700000]], which contains more than one search term, will be the applications of all restrictions.

A search term can be one of the following (the first three term are collectively called __search literals__):
* A metadata-based search, by specifying the name of a [[metadata key|00001006010000]], followed by a [[search operator|00001007705000]], followed by an optional [[search value|00001007706000]].

  A zero value of N will produce the same result as if nothing was specified.
  If specified multiple times, the lower value takes precedence.

  Example: ''PICK 5 PICK 3'' will be interpreted as ''PICK 3''.
* The string ''ORDER'', followed by a non-empty sequence of spaces and the name of a metadata key, will specify an ordering of the result list.
  If you include the string ''REVERSE'' after ''ORDER'' but before the metadata key, the ordering will be reversed.

  Example: ''ORDER published'' will order the resulting list based on the publishing data, while ''ORDER REVERSE published'' will return a reversed result order.

  An explicit order field will take precedence over the random order described below.

  If no random order is effective, a ``ORDER REVERSE id`` will be added.
  This makes the sort stable.

  Example: ``ORDER created`` will be interpreted as ``ORDER created ORDER REVERSE id``.

id: 00001007721200
title: Query: Unlinked Directive
role: manual
tags: #manual #zettelstore
syntax: zmk
created: 20211119133357
modified: 20230928190540

The value of a personal Zettelstore is determined in part by explicit connections between related zettel.
If the number of zettel grow, some of these connections are missing.
There are various reasons for this.
Maybe, you forgot that a zettel exists.
Or you add a zettel later, but forgot that previous zettel already mention its title.

id: 00001012000000
title: API
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20210126175322
modified: 20230928183244

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

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

There is an [[overview zettel|00001012920000]] that shows the structure of the endpoints used by the API and gives an indication about its use.

=== Authentication
If [[authentication is enabled|00001010040100]], most API calls must include an [[access token|00001010040700]] that proves the identity of the caller.
* [[Authenticate an user|00001012050200]] to obtain an access token
* [[Renew an access token|00001012050400]] without costly re-authentication
* [[Provide an access token|00001012050600]] when doing an API call

=== Zettel lists
* [[List all zettel|00001012051200]]
* [[Query the list of all zettel|00001012051400]]
* [[Determine a tag zettel|00001012051600]]

=== Working with zettel
* [[Create a new zettel|00001012053200]]
* [[Retrieve metadata and content of an existing zettel|00001012053300]]
* [[Retrieve metadata of an existing zettel|00001012053400]]
* [[Retrieve evaluated metadata and content of an existing zettel in various encodings|00001012053500]]
* [[Retrieve parsed metadata and content of an existing zettel in various encodings|00001012053600]]

id: 00001012051400
title: API: Query the list of all zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20220912111111
modified: 20231023162927
precursor: 00001012051200

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

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

The following actions are supported:
; ''MINn'' (parameter)
: Emit only those values with at least __n__ aggregated values.
  __n__ must be a positive integer, ''MIN'' must be given in upper-case letters.
; ''MAXn'' (parameter)
: Emit only those values with at most __n__ aggregated values.
  __n__ must be a positive integer, ''MAX'' must be given in upper-case letters.
; ''REINDEX'' (aggregate)
: Updates the internal search index for the selected zettel, roughly similar to the [[refresh|00001012080500]] API call.
  It is not really an aggregate, since it is used only for its side effect.
  It is allowed to specify another aggregate.
; Any [[metadata key|00001006020000]] of type [[Word|00001006035500]], [[WordSet|00001006036000]], or [[TagSet|00001006034000]] (aggregates)
: Emit an aggregate of the given metadata key.
  The key can be given in any letter case.

Only the first aggregate action will be executed.

id: 00001012051600
title: API: Determine a tag zettel
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20230928183339
modified: 20230929114937

The [[endpoint|00001012920000]] ''/z'' also allows you to determine a ""tag zettel"", i.e. a zettel that documents a given tag.

The query parameter ""''tag''"" allows you to specify a value that is interpreted as the name of a tag.
Zettelstore tries to determine the corresponding tag zettel.

A tag zettel is a zettel with the [[''role''|00001006020100]] value ""tag"" and a title that names the tag.
If there is more than one zettel that qualifies, the zettel with the highest zettel identifier is used.

For example, if you want to determine the tag zettel for the tag ""#api"", your request will be:
```sh
# curl -i 'http://127.0.0.1:23123/z?tag=%23api'
HTTP/1.1 302 Found
Content-Type: text/plain; charset=utf-8
Location: /z/00001019990010
Content-Length: 14

00001019990010
```

Alternatively, you can omit the ''#'' character at the beginning of the tag:
```sh
# curl -i 'http://127.0.0.1:23123/z?tag=api'
HTTP/1.1 302 Found
Content-Type: text/plain; charset=utf-8
Location: /z/00001019990010
Content-Length: 14

00001019990010
```

If there is a corresponding tag zettel, the response will use the HTTP status code 302 (""Found""), the HTTP response header ''Location'' will contain the URL of the tag zettel.
Its zettel identifier will be returned in the HTTP response body.

If you specified some more query parameter, these will be part of the URL in the response header ''Location'':

```sh
# curl -i 'http://127.0.0.1:23123/z?tag=%23api&part=zettel'
HTTP/1.1 302 Found
Content-Type: text/plain; charset=utf-8
Location: /z/00001019990010?part=zettel
Content-Length: 14

00001019990010
```

Otherwise, if no tag zettel was found, the response will use the HTTP status code 404 (""Not found"").

```sh
# curl -i 'http://127.0.0.1:23123/z?tag=notag'
HTTP/1.1 404 Not Found
Content-Type: text/plain; charset=utf-8
Content-Length: 29

Tag zettel not found: #notag
```

To fulfill this service, Zettelstore will evaluate internally the query ''role:tag title=TAG'', there ''TAG'' is the actual tag.

Of course, if you are interested in the URL of the tag zettel, you can make use of the HTTP ''HEAD'' method:

```sh
# curl -I 'http://127.0.0.1:23123/z?tag=%23api'
HTTP/1.1 302 Found
Content-Type: text/plain; charset=utf-8
Location: /z/00001019990010
Content-Length: 14
```

=== HTTP Status codes
; ''302''
: Tag zettel was found.
  The HTTP header ''Location'' contains its URL, the body of the response contains its zettel identifier.
; ''404''
: No zettel for the given tag was found.

id: 00001012070500
title: API: Retrieve administrative data
role: manual
tags: #api #manual #zettelstore
syntax: zmk
created: 20220304164242
modified: 20230928190516

The [[endpoint|00001012920000]] ''/x'' allows you to retrieve some (administrative) data.

Currently, you can only request Zettelstore version data.

````
# curl 'http://127.0.0.1:23123/x'

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

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

  Its [[''syntax''|00001006020000#syntax]] must be set to ""[[css|00001008000000#css]]"".
  The content must contain the role-specific CSS code, for example ``body {background-color: #FFFFD0}``for a background in a light yellow color.

  Let's assume, the newly created CSS zettel got the identifier ''20220825200100''.

  Now, you have to map this freshly created zettel to a role, for example ""zettel"".
  Since you have enabled ''expert-mode'', you are allowed to modify the zettel ""[[Zettelstore Sxn Start Code|00000000019000]]"".
  Add the following code to the Sxn Start Code zettel: ``(set! CSS-ROLE-map '(("zettel" . "20220825200100")))``.

  In general, the mapping must follow the pattern: ``(ROLE . ID)``, where ''ROLE'' is the placeholder for the role, and ''ID'' for the zettel identifier containing CSS code.
  For example, if you also want the role ""configuration"" to be rendered using that CSS, the code should be something like ``(set! CSS-ROLE-map '(("zettel" . "20220825200100") ("configuration" . "20220825200100")))``.
* **Discussion:** you have to ensure that the CSS zettel is allowed to be read by the intended audience of the zettel with that given role.
  For example, if you made zettel with a specific role public visible, the CSS zettel must also have a [[''visibility: public''|00001010070200]] metadata.

=== Zettel synchronization with iCloud (Apple)
* **Problem:** You use Zettelstore on various macOS computers and you want to use the sameset of zettel across all computers.
* **Solution:** Place your zettel in an iCloud folder.

id: 00001019990010
title: #api
role: tag
syntax: zmk
created: 20230928185004
modified: 20230928185204

Zettel with the tag ''#api'' contain a description of the [[API|00001012000000]].

			encoderMD:    "",
			encoderSz:    `(BLOCK (DESCRIPTION (INLINE (TEXT "Zettel")) (BLOCK (BLOCK (PARA (TEXT "Paper")) (PARA (TEXT "Note")))) (INLINE (TEXT "Zettelkasten")) (BLOCK (BLOCK (PARA (TEXT "Slip") (SPACE) (TEXT "box"))))))`,
			encoderSHTML: `((dl (dt "Zettel") (dd (p "Paper") (p "Note")) (dt "Zettelkasten") (dd (p "Slip" " " "box"))))`,
			encoderText:  "Zettel\nPaper\nNote\nZettelkasten\nSlip box",
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Description List with keys, but no descriptions",
		zmk:   "; K1\n: D11\n: D12\n; K2\n; K3\n: D31",
		expect: expectMap{
			encoderHTML:  "<dl><dt>K1</dt><dd><p>D11</p></dd><dd><p>D12</p></dd><dt>K2</dt><dt>K3</dt><dd><p>D31</p></dd></dl>",
			encoderMD:    "",
			encoderSz:    `(BLOCK (DESCRIPTION (INLINE (TEXT "K1")) (BLOCK (BLOCK (PARA (TEXT "D11"))) (BLOCK (PARA (TEXT "D12")))) (INLINE (TEXT "K2")) (BLOCK) (INLINE (TEXT "K3")) (BLOCK (BLOCK (PARA (TEXT "D31"))))))`,
			encoderSHTML: `((dl (dt "K1") (dd (p "D11")) (dd (p "D12")) (dt "K2") (dt "K3") (dd (p "D31"))))`,
			encoderText:  "K1\nD11\nD12\nK2\nK3\nD31",
			encoderZmk:   useZmk,
		},
	},
	{
		descr: "Simple Table",
		zmk:   "|c1|c2|c3\n|d1||d3",
		expect: expectMap{
			encoderHTML:  `<table><tbody><tr><td>c1</td><td>c2</td><td>c3</td></tr><tr><td>d1</td><td></td><td>d3</td></tr></tbody></table>`,
			encoderMD:    "",
			encoderSz:    `(BLOCK (TABLE () (list (CELL (TEXT "c1")) (CELL (TEXT "c2")) (CELL (TEXT "c3"))) (list (CELL (TEXT "d1")) (CELL) (CELL (TEXT "d3")))))`,

				ap.max = num
				continue
			}
		}
		if act == "TITLE" && i+1 < len(actions) {
			ap.title = strings.Join(actions[i+1:], " ")
			break
		}
		if act == "REINDEX" {
			continue
		}
		acts = append(acts, act)
	}
	var firstUnknownKey string
	for _, act := range acts {
		switch act {
		case "ATOM":

module zettelstore.de/z

go 1.21

require (
	github.com/fsnotify/fsnotify v1.7.0
	github.com/yuin/goldmark v1.5.6
	golang.org/x/crypto v0.14.0
	golang.org/x/term v0.13.0
	golang.org/x/text v0.13.0
	zettelstore.de/client.fossil v0.0.0-20231026155719-8c6fa07a0d0f
	zettelstore.de/sx.fossil v0.0.0-20231026154942-e6a183740a4f
)

require golang.org/x/sys v0.13.0 // indirect

github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
github.com/yuin/goldmark v1.5.6 h1:COmQAWTCcGetChm3Ig7G/t8AFAN00t+o8Mt4cf7JpwA=
github.com/yuin/goldmark v1.5.6/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=

golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.13.0 h1:bb+I9cTfFazGW51MZqBVmZy7+JEJMouUHTUSKVQLBek=
golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
zettelstore.de/client.fossil v0.0.0-20231026155719-8c6fa07a0d0f h1:eW8wEMcqR+LvIwWxE1rl+6LZbXRM9wgBGQ9pPw/k1j8=
zettelstore.de/client.fossil v0.0.0-20231026155719-8c6fa07a0d0f/go.mod h1:uYFsUH4hQ/TLEjDFxzOLJkT/sltvcQ5aIM29XNkjR+c=
zettelstore.de/sx.fossil v0.0.0-20231026154942-e6a183740a4f h1:NFblKWyhNnXDDcF7C6zx7cDyIJ/7GGAusIwR6uZrfkM=
zettelstore.de/sx.fossil v0.0.0-20231026154942-e6a183740a4f/go.mod h1:Uw3OLM1ufOM4Xe0G51mvkTDUv2okd+HyDBMx+0ZG7ME=

	}
	// TODO: check proper end </svg>
	return svgSrc
}

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





	objs, err := rd.ReadAll()
	if err != nil {
		return ast.BlockSlice{
			&ast.VerbatimNode{
				Kind:    ast.VerbatimProg,
				Attrs:   attrs.Attributes{"": syntax},
				Content: inp.ScanLineContent(),

type parserState struct {
	inp *input.Input
}

func (ps *parserState) mustStop() bool { return ps.inp.Ch == input.EOS }
func (ps *parserState) acceptSingleKw(s string) bool {
	if ps.inp.Accept(s) && (ps.isSpace() || ps.isActionSep() || ps.mustStop()) {
		return true
	}
	return false
}
func (ps *parserState) acceptKwArgs(s string) bool {
	if ps.inp.Accept(s) && ps.isSpace() {
		ps.skipSpace()

		if ps.acceptKwArgs(api.LimitDirective) {
			if s, ok := ps.parseLimit(q); ok {
				q = s
				continue
			}
		}
		inp.SetPos(pos)
		if ps.isActionSep() {
			q = ps.parseActions(q)
			break
		}
		q = ps.parseText(q)
	}
	return q
}

	}
	text, key := ps.scanSearchTextOrKey(hasOp)
	if len(key) > 0 {
		// Assert: hasOp == false
		op, hasOp = ps.scanSearchOp()
		// Assert hasOp == true
		if op == cmpExist || op == cmpNotExist {
			if ps.isSpace() || ps.isActionSep() || ps.mustStop() {
				return q.addKey(string(key), op)
			}
			ps.inp.SetPos(pos)
			hasOp = false
			text = ps.scanWord()
			key = nil
		} else {

}

func (ps *parserState) scanSearchTextOrKey(hasOp bool) ([]byte, []byte) {
	inp := ps.inp
	pos := inp.Pos
	allowKey := !hasOp

	for !ps.isSpace() && !ps.isActionSep() && !ps.mustStop() {
		if allowKey {
			switch inp.Ch {
			case searchOperatorNotChar, existOperatorChar,
				searchOperatorEqualChar, searchOperatorHasChar,
				searchOperatorPrefixChar, searchOperatorSuffixChar, searchOperatorMatchChar,
				searchOperatorLessChar, searchOperatorGreaterChar:
				allowKey = false
				if key := inp.Src[pos:inp.Pos]; meta.KeyIsValid(string(key)) {
					return nil, key
				}
			}
		}
		inp.Next()
	}
	return inp.Src[pos:inp.Pos], nil
}

func (ps *parserState) scanWord() []byte {
	inp := ps.inp
	pos := inp.Pos
	for !ps.isSpace() && !ps.isActionSep() && !ps.mustStop() {
		inp.Next()
	}
	return inp.Src[pos:inp.Pos]
}

func (ps *parserState) scanPosInt() (int, bool) {
	word := ps.scanWord()

	}
	if negate {
		return op.negate(), true
	}
	return op, true
}















func (ps *parserState) skipSpace() {
	for ps.isSpace() {
		ps.inp.Next()
	}
}

func (ps *parserState) isSpace() bool {
	switch ch := ps.inp.Ch; ch {
	case input.EOS:
		return false
	case ' ', '\t', '\n', '\r':
		return true
	default:
		return input.IsSpace(ch)
	}
}

func (ps *parserState) isActionSep() bool {
	return ps.inp.Ch == actionSeparatorChar
}

func TestParser(t *testing.T) {
	t.Parallel()
	testcases := []struct {
		spec string
		exp  string
	}{
		{"1", "1"}, // Just a number will transform to search for that number in all zettel

		{"1 IDENT", "00000000000001 IDENT"},
		{"IDENT", "IDENT"},
		{"1 IDENT|REINDEX", "00000000000001 IDENT | REINDEX"},

		{"1 ITEMS", "00000000000001 ITEMS"},
		{"ITEMS", "ITEMS"},

		{"CONTEXT", "CONTEXT"}, {"CONTEXT a", "CONTEXT a"},
		{"0 CONTEXT", "0 CONTEXT"}, {"1 CONTEXT", "00000000000001 CONTEXT"},
		{"00000000000001 CONTEXT", "00000000000001 CONTEXT"},
		{"100000000000001 CONTEXT", "100000000000001 CONTEXT"},
		{"1 CONTEXT BACKWARD", "00000000000001 CONTEXT BACKWARD"},
		{"1 CONTEXT FORWARD", "00000000000001 CONTEXT FORWARD"},
		{"1 CONTEXT COST ", "00000000000001 CONTEXT COST"},
		{"1 CONTEXT COST 3", "00000000000001 CONTEXT COST 3"}, {"1 CONTEXT COST x", "00000000000001 CONTEXT COST x"},
		{"1 CONTEXT MAX 5", "00000000000001 CONTEXT MAX 5"}, {"1 CONTEXT MAX y", "00000000000001 CONTEXT MAX y"},
		{"1 CONTEXT MAX 5 COST 7", "00000000000001 CONTEXT COST 7 MAX 5"},
		{"1 CONTEXT |  N", "00000000000001 CONTEXT | N"},
		{"1 1 CONTEXT", "00000000000001 CONTEXT"},
		{"1 2 CONTEXT", "00000000000001 00000000000002 CONTEXT"},
		{"2 1 CONTEXT", "00000000000002 00000000000001 CONTEXT"},
		{"1 CONTEXT|N", "00000000000001 CONTEXT | N"},

		{"CONTEXT 0", "CONTEXT 0"},

		{"1 UNLINKED", "00000000000001 UNLINKED"},
		{"UNLINKED", "UNLINKED"},
		{"1 UNLINKED PHRASE", "00000000000001 UNLINKED PHRASE"},
		{"1 UNLINKED PHRASE Zettel", "00000000000001 UNLINKED PHRASE Zettel"},

id: 20230929102100
title: #test
role: tag
syntax: zmk
created: 20230929102125

Zettel with this tag are testing the Zettelstore.

		}

	}
}

func TestListZettel(t *testing.T) {
	const (
		ownerZettel      = 50
		configRoleZettel = 32
		writerZettel     = ownerZettel - 24
		readerZettel     = ownerZettel - 24
		creatorZettel    = 8
		publicZettel     = 4
	)

	testdata := []struct {
		user string
		exp  int
	}{

	c := getClient()
	c.SetAuth("owner", "owner")
	_, _, metaSeq, err := c.QueryZettelData(context.Background(), string(api.ZidTOCNewTemplate)+" "+api.ItemsDirective)
	if err != nil {
		t.Error(err)
		return
	}
	if got := len(metaSeq); got != 3 {
		t.Errorf("Expected list of length 3, got %d", got)
		return
	}
	checkListZid(t, metaSeq, 0, api.ZidTemplateNewZettel)
	checkListZid(t, metaSeq, 1, api.ZidTemplateNewTag)
	checkListZid(t, metaSeq, 2, api.ZidTemplateNewUser)
}

// func TestGetZettelContext(t *testing.T) {
// 	const (
// 		allUserZid = api.ZettelID("20211019200500")
// 		ownerZid   = api.ZettelID("20210629163300")
// 		writerZid  = api.ZettelID("20210629165000")

		size int
	}{
		{"#invisible", 1},
		{"#user", 4},
		{"#test", 4},
	}
	if len(agg) != len(tags) {
		t.Errorf("Expected %d different tags, but got %d (%v)", len(tags), len(agg), agg)
	}
	for _, tag := range tags {
		if zl, ok := agg[tag.key]; !ok {
			t.Errorf("No tag %v: %v", tag.key, agg)
		} else if len(zl) != tag.size {
			t.Errorf("Expected %d zettel with tag %v, but got %v", tag.size, tag.key, zl)
		}
	}
	for i, id := range agg["#user"] {
		if id != agg["#test"][i] {
			t.Errorf("Tags #user and #test have different content: %v vs %v", agg["#user"], agg["#test"])
		}
	}
}

func TestTagZettel(t *testing.T) {
	t.Parallel()
	c := getClient()
	c.AllowRedirect(true)
	c.SetAuth("owner", "owner")
	ctx := context.Background()
	zid, err := c.TagZettel(ctx, "nosuchtag")
	if err != nil {
		t.Error(err)
	} else if zid != "" {
		t.Errorf("no zid expected, but got %q", zid)
	}
	zid, err = c.TagZettel(ctx, "#test")
	exp := api.ZettelID("20230929102100")
	if err != nil {
		t.Error(err)
	} else if zid != exp {
		t.Errorf("tag zettel for #test should be %q, but got %q", exp, zid)
	}
}

func TestListRoles(t *testing.T) {
	t.Parallel()
	c := getClient()
	c.SetAuth("owner", "owner")
	agg, err := c.QueryAggregate(context.Background(), api.ActionSeparator+api.KeyRole)
	if err != nil {
		t.Error(err)
		return
	}
	exp := []string{"configuration", "user", "tag", "zettel"}
	if len(agg) != len(exp) {
		t.Errorf("Expected %d different roles, but got %d (%v)", len(exp), len(agg), agg)
	}
	for _, id := range exp {
		if _, found := agg[id]; !found {
			t.Errorf("Role map expected key %q", id)
		}
	}
}

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

// Package main provides a command to build and run the software.
package main

import (
	"archive/zip"
	"bytes"
	"errors"
	"flag"
	"fmt"
	"io"
	"io/fs"
	"net"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"zettelstore.de/client.fossil/api"
	"zettelstore.de/z/input"
	"zettelstore.de/z/strfun"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

var envDirectProxy = []string{"GOPROXY=direct"}
var envGoVCS = []string{"GOVCS=zettelstore.de:fossil"}

func executeCommand(env []string, name string, arg ...string) (string, error) {
	logCommand("EXEC", env, name, arg)

	for _, entry := range entries {
		if err = createManualZipEntry(manualPath, entry, zipWriter); err != nil {
			return err
		}
	}
	return nil
}

const versionZid = "00001000000001"

func createManualZipEntry(path string, entry fs.DirEntry, zipWriter *zip.Writer) error {
	info, err := entry.Info()
	if err != nil {
		return err
	}
	fh, err := zip.FileInfoHeader(info)
	if err != nil {
		return err
	}
	name := entry.Name()
	fh.Name = name
	fh.Method = zip.Deflate
	w, err := zipWriter.CreateHeader(fh)
	if err != nil {
		return err
	}
	manualFile, err := os.Open(filepath.Join(path, name))
	if err != nil {
		return err
	}
	defer manualFile.Close()

	if name != versionZid+".zettel" {
		_, err = io.Copy(w, manualFile)
		return err
	}

	data, err := io.ReadAll(manualFile)
	if err != nil {
		return err
	}
	inp := input.NewInput(data)
	m := meta.NewFromInput(id.MustParse(versionZid), inp)
	m.SetNow(api.KeyModified)

	var buf bytes.Buffer
	if _, err = fmt.Fprintf(&buf, "id: %s\n", versionZid); err != nil {
		return err
	}
	if _, err = m.WriteComputed(&buf); err != nil {
		return err
	}
	version := getVersion()
	if _, err = fmt.Fprintf(&buf, "\n%s", version); err != nil {
		return err
	}
	_, err = io.Copy(w, &buf)
	return err
}

func getReleaseVersionData() string {
	if fossil := getFossilDirty(); fossil != "" {
		fmt.Fprintln(os.Stderr, "Warning: releasing a dirty version")
	}

		rtConfig: rtConfig,
		port:     port,
	}
}

// PrepareCopy the zettel for further modification.
func (*CreateZettel) PrepareCopy(origZettel zettel.Zettel) zettel.Zettel {
	origMeta := origZettel.Meta
	m := origMeta.Clone()
	if title, found := origMeta.Get(api.KeyTitle); found {
		m.Set(api.KeyTitle, prependTitle(title, "Copy", "Copy of "))
	}
	setReadonly(m)
	content := origZettel.Content
	content.TrimSpace()
	return zettel.Zettel{Meta: m, Content: content}
}

	m.Set(api.KeyPrecursor, origMeta.Zid.String())
	return zettel.Zettel{Meta: m, Content: zettel.NewContent(nil)}
}

// PrepareChild the zettel for further modification.
func (*CreateZettel) PrepareChild(origZettel zettel.Zettel) zettel.Zettel {
	origMeta := origZettel.Meta
	m := meta.New(id.Invalid)
	if title, found := origMeta.Get(api.KeyTitle); found {
		m.Set(api.KeyTitle, prependTitle(title, "Child", "Child of "))
	}
	updateMetaRoleTagsSyntax(m, origMeta)
	m.Set(api.KeySuperior, origMeta.Zid.String())
	return zettel.Zettel{Meta: m, Content: zettel.NewContent(nil)}
}

// PrepareNew the zettel for further modification.
func (*CreateZettel) PrepareNew(origZettel zettel.Zettel, newTitle string) zettel.Zettel {
	m := meta.New(id.Invalid)
	om := origZettel.Meta
	m.SetNonEmpty(api.KeyTitle, om.GetDefault(api.KeyTitle, ""))
	updateMetaRoleTagsSyntax(m, om)

	const prefixLen = len(meta.NewPrefix)
	for _, pair := range om.PairsRest() {
		if key := pair.Key; len(key) > prefixLen && key[0:prefixLen] == meta.NewPrefix {
			m.Set(key[prefixLen:], pair.Value)
		}
	}
	if newTitle != "" {
		m.Set(api.KeyTitle, newTitle)
	}
	content := origZettel.Content
	content.TrimSpace()
	return zettel.Zettel{Meta: m, Content: content}
}

func updateMetaRoleTagsSyntax(m, orig *meta.Meta) {
	m.SetNonEmpty(api.KeyRole, orig.GetDefault(api.KeyRole, ""))

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

package usecase

import (
	"context"

	"zettelstore.de/client.fossil/api"
	"zettelstore.de/z/query"
	"zettelstore.de/z/zettel"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

// TagZettel is the usecase of retrieving a "tag zettel", i.e. a zettel that
// describes a given tag. A tag zettel must habe the tag's name in its title
// and must have a role=tag.

// TagZettelPort is the interface used by this use case.
type TagZettelPort interface {
	// GetZettel retrieves a specific zettel.
	GetZettel(ctx context.Context, zid id.Zid) (zettel.Zettel, error)
}

// TagZettel is the data for this use case.
type TagZettel struct {
	port  GetZettelPort
	query *Query
}

// NewTagZettel creates a new use case.
func NewTagZettel(port GetZettelPort, query *Query) TagZettel {
	return TagZettel{port: port, query: query}
}

// Run executes the use case.
func (uc TagZettel) Run(ctx context.Context, tag string) (zettel.Zettel, error) {
	tag = meta.NormalizeTag(tag)
	q := query.Parse(
		api.KeyTitle + api.SearchOperatorEqual + tag + " " +
			api.KeyRole + api.SearchOperatorHas + api.ValueRoleTag)
	ml, err := uc.query.Run(ctx, q)
	if err != nil {
		return zettel.Zettel{}, err
	}
	for _, m := range ml {
		z, errZ := uc.port.GetZettel(ctx, m.Zid)
		if errZ == nil {
			return z, nil
		}
	}
	return zettel.Zettel{}, ErrTagZettelNotFound{Tag: tag}
}

// ErrTagZettelNotFound is returned if a tag zettel was not found.
type ErrTagZettelNotFound struct{ Tag string }

func (etznf ErrTagZettelNotFound) Error() string { return "tag zettel not found: " + etznf.Tag }

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

package usecase

import (
	"context"

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

// ReIndexPort is the interface used by this use case.
type ReIndexPort interface {
	ReIndex(context.Context, id.Zid) error
}

// ReIndex is the data for this use case.
type ReIndex struct {
	log  *logger.Logger
	port ReIndexPort
}

// NewReIndex creates a new use case.
func NewReIndex(log *logger.Logger, port ReIndexPort) ReIndex {
	return ReIndex{log: log, port: port}
}

// Run executes the use case.
func (uc *ReIndex) Run(ctx context.Context, zid id.Zid) error {
	err := uc.port.ReIndex(ctx, zid)
	uc.log.Sense().User(ctx).Err(err).Zid(zid).Msg("ReIndex zettel")
	return err
}

package api

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"zettelstore.de/client.fossil/api"
	"zettelstore.de/client.fossil/sexp"
	"zettelstore.de/sx.fossil"
	"zettelstore.de/z/query"
	"zettelstore.de/z/usecase"
	"zettelstore.de/z/web/adapter"
	"zettelstore.de/z/web/content"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

// MakeQueryHandler creates a new HTTP handler to perform a query.
func (a *API) MakeQueryHandler(queryMeta *usecase.Query, tagZettel *usecase.TagZettel, reIndex *usecase.ReIndex) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		ctx := r.Context()
		urlQuery := r.URL.Query()
		if a.handleTagZettel(w, r, tagZettel, urlQuery) {
			return
		}

		sq := adapter.GetQuery(urlQuery)

		metaSeq, err := queryMeta.Run(ctx, sq)
		if err != nil {
			a.reportUsecaseError(w, err)
			return
		}

		var encoder zettelEncoder
		var contentType string
		switch enc, _ := getEncoding(r, urlQuery); enc {
		case api.EncoderPlain:
			encoder = &plainZettelEncoder{}
			contentType = content.PlainText

		case api.EncoderData:
			encoder = &dataZettelEncoder{
				sf:        sx.MakeMappedFactory(256),
				sq:        sq,
				getRights: func(m *meta.Meta) api.ZettelRights { return a.getRights(ctx, m) },
			}
			contentType = content.SXPF

		default:
			http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
			return
		}

		var buf bytes.Buffer
		err = queryAction(&buf, encoder, metaSeq, sq, func(zid id.Zid) error { return reIndex.Run(ctx, zid) })
		if err != nil {
			a.log.Error().Err(err).Str("query", sq.String()).Msg("execute query action")
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		}

		if err = writeBuffer(w, &buf, contentType); err != nil {
			a.log.Error().Err(err).Msg("write result buffer")
		}
	}
}
func queryAction(w io.Writer, enc zettelEncoder, ml []*meta.Meta, sq *query.Query, reindex func(id.Zid) error) error {
	min, max := -1, -1
	if actions := sq.Actions(); len(actions) > 0 {
		acts := make([]string, 0, len(actions))
		for _, act := range actions {
			if strings.HasPrefix(act, "MIN") {
				if num, err := strconv.Atoi(act[3:]); err == nil && num > 0 {
					min = num

			}
			acts = append(acts, act)
		}
		for _, act := range acts {
			switch act {
			case "KEYS":
				return encodeKeysArrangement(w, enc, ml, act)
			case "REINDEX":
				for _, m := range ml {
					if err := reindex(m.Zid); err != nil {
						return err
					}
				}
			}
			switch key := strings.ToLower(act); meta.Type(key) {
			case meta.TypeWord, meta.TypeTagSet:
				return encodeMetaKeyArrangement(w, enc, ml, key, min, max)
			}
		}
	}

		sx.String(act),
		sx.MakeList(sf.MustMake("query"), sx.String(dze.sq.String())),
		sx.MakeList(sf.MustMake("human"), sx.String(dze.sq.Human())),
		result.Cons(sf.MustMake("list")),
	))
	return err
}

func (a *API) handleTagZettel(w http.ResponseWriter, r *http.Request, tagZettel *usecase.TagZettel, vals url.Values) bool {
	tag := vals.Get(api.QueryKeyTag)
	if tag == "" {
		return false
	}
	ctx := r.Context()
	z, err := tagZettel.Run(ctx, tag)
	if err != nil {
		a.reportUsecaseError(w, err)
		return true
	}
	zid := z.Meta.Zid.String()
	w.Header().Set(api.HeaderContentType, content.PlainText)
	newURL := a.NewURLBuilder('z').SetZid(api.ZettelID(zid))
	for key, slVals := range vals {
		if key == api.QueryKeyTag {
			continue
		}
		for _, val := range slVals {
			newURL.AppendKVQuery(key, val)
		}
	}
	http.Redirect(w, r, newURL.String(), http.StatusFound)
	if _, err = io.WriteString(w, zid); err != nil {
		a.log.Error().Err(err).Msg("redirect body")
	}
	return true
}

	if errors.As(err, &eiz) {
		return http.StatusBadRequest, fmt.Sprintf("Zettel-ID %q not appropriate in this context", eiz.Zid)
	}
	var ezin usecase.ErrZidInUse
	if errors.As(err, &ezin) {
		return http.StatusBadRequest, fmt.Sprintf("Zettel-ID %q already in use", ezin.Zid)
	}
	var etznf usecase.ErrTagZettelNotFound
	if errors.As(err, &etznf) {
		return http.StatusNotFound, "Tag zettel not found: " + etznf.Tag
	}
	var ebr ErrBadRequest
	if errors.As(err, &ebr) {
		return http.StatusBadRequest, ebr.Text
	}
	if errors.Is(err, box.ErrStopped) {
		return http.StatusInternalServerError, fmt.Sprintf("Zettelstore not operational: %v", err)
	}

// under this license.
//-----------------------------------------------------------------------------

package webui

// WebUI related constants.

const queryKeyAction = "_action"

// Values for queryKeyAction
const (
	valueActionChild   = "child"
	valueActionCopy    = "copy"
	valueActionFolge   = "folge"
	valueActionNew     = "new"

			wui.renderZettelForm(ctx, w, createZettel.PrepareChild(origZettel), "Child Zettel", "", roleData, syntaxData)
		case actionCopy:
			wui.renderZettelForm(ctx, w, createZettel.PrepareCopy(origZettel), "Copy Zettel", "", roleData, syntaxData)
		case actionFolge:
			wui.renderZettelForm(ctx, w, createZettel.PrepareFolge(origZettel), "Folge Zettel", "", roleData, syntaxData)
		case actionNew:
			title := parser.NormalizedSpacedText(origZettel.Meta.GetTitle())
			newTitle := parser.NormalizedSpacedText(q.Get(api.KeyTitle))
			wui.renderZettelForm(ctx, w, createZettel.PrepareNew(origZettel, newTitle), title, "", roleData, syntaxData)
		case actionVersion:
			wui.renderZettelForm(ctx, w, createZettel.PrepareVersion(origZettel), "Version Zettel", "", roleData, syntaxData)
		}
	}
}

func retrieveDataLists(ctx context.Context, ucListRoles usecase.ListRoles, ucListSyntax usecase.ListSyntax) ([]string, []string) {

			rb.bindString("shadowed-box", nil)
			rb.bindString("incoming", wui.encodeIncoming(m, wui.makeGetTextTitle(ctx, getZettel)))
		}
		wui.bindCommonZettelData(ctx, &rb, user, m, nil)

		if rb.err == nil {
			err = wui.renderSxnTemplate(ctx, w, id.DeleteTemplateZid, env)
		} else {
			err = rb.err
		}
		if err != nil {
			wui.reportError(ctx, w, err)
		}
	}
}

	}
	if postTitle, ok := trimmedFormValue(r, "title"); ok {
		m.Set(api.KeyTitle, meta.RemoveNonGraphic(postTitle))
	}
	if postTags, ok := trimmedFormValue(r, "tags"); ok {
		if tags := meta.ListFromValue(meta.RemoveNonGraphic(postTags)); len(tags) > 0 {
			for i, tag := range tags {

				tags[i] = meta.NormalizeTag(tag)

			}
			m.SetList(api.KeyTags, tags)
		}
	}
	if postRole, ok := trimmedFormValue(r, "role"); ok {
		m.SetWord(api.KeyRole, meta.RemoveNonGraphic(postRole))
	}

		rb.bindString("query-key-phrase", sx.String(api.QueryKeyPhrase))
		rb.bindString("enc-eval", wui.infoAPIMatrix(zid, false, encTexts))
		rb.bindString("enc-parsed", wui.infoAPIMatrixParsed(zid, encTexts))
		rb.bindString("shadow-links", shadowLinks)
		wui.bindCommonZettelData(ctx, &rb, user, zn.InhMeta, &zn.Content)
		if rb.err == nil {
			err = wui.renderSxnTemplate(ctx, w, id.InfoTemplateZid, env)
		} else {
			err = rb.err
		}
		if err != nil {
			wui.reportError(ctx, w, err)
		}
	}
}

			for _, part := range []string{"meta", "actions", "heading"} {
				rb.rebindResolved("ROLE-"+role+"-"+part, "ROLE-DEFAULT-"+part)
			}
		}
		wui.bindCommonZettelData(ctx, &rb, user, zn.InhMeta, &zn.Content)
		if rb.err == nil {
			err = wui.renderSxnTemplate(ctx, w, id.ZettelTemplateZid, env)
		} else {
			err = rb.err
		}
		if err != nil {
			wui.reportError(ctx, w, err)
		}
	}
}

					sx.Cons(wui.sf.MustMake("datetime"), sx.String(ts.Format("2006-01-02T15:04:05"))),
				),
				sx.MakeList(wui.sf.MustMake(sxhtml.NameSymNoEscape), sx.String(ts.Format("2006-01-02 15:04:05"))),
			)
		}
		return sx.Nil()
	case meta.TypeURL:
		return wui.url2html(sx.String(value))




	case meta.TypeWord:
		return wui.transformLink(key, value, value)
	case meta.TypeWordSet:
		return wui.transformWordSet(key, meta.ListFromValue(value))
	case meta.TypeZettelmarkup:
		return wui.transformZmkMetadata(value, evalMetadata, gen)
	default:

package webui

import (
	"context"
	"io"
	"net/http"
	"net/url"
	"slices"
	"strconv"
	"strings"

	"zettelstore.de/client.fossil/api"
	"zettelstore.de/sx.fossil"
	"zettelstore.de/z/ast"
	"zettelstore.de/z/encoding/atom"
	"zettelstore.de/z/encoding/rss"
	"zettelstore.de/z/encoding/xml"
	"zettelstore.de/z/evaluator"
	"zettelstore.de/z/query"
	"zettelstore.de/z/usecase"
	"zettelstore.de/z/web/adapter"
	"zettelstore.de/z/web/server"
	"zettelstore.de/z/zettel/id"
	"zettelstore.de/z/zettel/meta"
)

// MakeListHTMLMetaHandler creates a HTTP handler for rendering the list of zettel as HTML.
func (wui *WebUI) MakeListHTMLMetaHandler(queryMeta *usecase.Query, tagZettel *usecase.TagZettel, reIndex *usecase.ReIndex) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		urlQuery := r.URL.Query()
		if wui.handleTagZettel(w, r, tagZettel, urlQuery) {
			return
		}
		q := adapter.GetQuery(urlQuery)
		q = q.SetDeterministic()
		ctx := r.Context()
		metaSeq, err := queryMeta.Run(ctx, q)
		if err != nil {
			wui.reportError(ctx, w, err)
			return
		}
		if actions := q.Actions(); len(actions) > 0 {
			var tempActions []string
			for _, act := range actions {
				if act == "REINDEX" {
					for _, m := range metaSeq {
						if err = reIndex.Run(ctx, m.Zid); err != nil {
							wui.reportError(ctx, w, err)
							return
						}
					}
					continue
				}
				tempActions = append(tempActions, act)
			}
			actions = tempActions
			if len(actions) > 0 {
				switch actions[0] {
				case "ATOM":
					wui.renderAtom(w, q, metaSeq)
					return
				case "RSS":
					wui.renderRSS(ctx, w, q, metaSeq)
					return
				}
			}
		}
		var content, endnotes *sx.Pair
		if bn := evaluator.QueryAction(ctx, q, metaSeq, wui.rtConfig); bn != nil {
			enc := wui.getSimpleHTMLEncoder()
			content, endnotes, err = enc.BlocksSxn(&ast.BlockSlice{bn})
			if err != nil {

		} else {
			var sb strings.Builder
			q.PrintHuman(&sb)
			rb.bindString("heading", sx.String(sb.String()))
		}
		rb.bindString("query-value", sx.String(q.String()))
		if tzl := q.GetMetaValues(api.KeyTags); len(tzl) > 0 {
			sxTzl, sxNoTzl := wui.transformTagZettelList(ctx, tagZettel, tzl)
			if !sx.IsNil(sxTzl) {
				rb.bindString("tag-zettel", sxTzl)
			}
			if !sx.IsNil(sxNoTzl) {
				rb.bindString("create-tag-zettel", sxNoTzl)
			}
		}
		rb.bindString("content", content)
		rb.bindString("endnotes", endnotes)
		apiURL := wui.NewURLBuilder('z').AppendQuery(q.String())
		seed, found := q.GetSeed()
		if found {
			apiURL = apiURL.AppendKVQuery(api.QueryKeySeed, strconv.Itoa(seed))
		} else {
			seed = 0
		}
		rb.bindString("plain-url", sx.String(apiURL.String()))
		rb.bindString("data-url", sx.String(apiURL.AppendKVQuery(api.QueryKeyEncoding, api.EncodingData).String()))
		if wui.canCreate(ctx, user) {
			rb.bindString("create-url", sx.String(wui.createNewURL))
			rb.bindString("seed", sx.Int64(seed))
		}
		if rb.err == nil {
			err = wui.renderSxnTemplate(ctx, w, id.ListTemplateZid, env)
		} else {
			err = rb.err
		}
		if err != nil {
			wui.reportError(ctx, w, err)
		}
	}
}

func (wui *WebUI) transformTagZettelList(ctx context.Context, tagZettel *usecase.TagZettel, tags []string) (withZettel, withoutZettel *sx.Pair) {

	slices.Reverse(tags)
	for _, tag := range tags {
		if _, err := tagZettel.Run(ctx, tag); err == nil {
			u := wui.NewURLBuilder('h').AppendKVQuery(api.QueryKeyTag, tag)
			withZettel = wui.prependTagZettel(withZettel, tag, u)
		} else {
			u := wui.NewURLBuilder('c').SetZid(api.ZidTemplateNewTag).AppendKVQuery(queryKeyAction, valueActionNew).AppendKVQuery(api.KeyTitle, tag)
			withoutZettel = wui.prependTagZettel(withoutZettel, tag, u)
		}
	}
	return withZettel, withoutZettel
}

func (wui *WebUI) prependTagZettel(sxZtl *sx.Pair, tag string, u *api.URLBuilder) *sx.Pair {
	link := sx.MakeList(
		wui.symA,
		sx.MakeList(
			wui.symAttr,
			sx.Cons(wui.symHref, sx.String(u.String())),
		),
		sx.String(tag),
	)
	if sxZtl != nil {
		sxZtl = sxZtl.Cons(sx.String(", "))
	}


	return sxZtl.Cons(link)
}

func (wui *WebUI) renderRSS(ctx context.Context, w http.ResponseWriter, q *query.Query, ml []*meta.Meta) {
	var rssConfig rss.Configuration
	rssConfig.Setup(ctx, wui.rtConfig)
	if actions := q.Actions(); len(actions) > 2 && actions[1] == "TITLE" {
		rssConfig.Title = strings.Join(actions[2:], " ")

	if _, err = io.WriteString(w, xml.Header); err == nil {
		_, err = w.Write(data)
	}
	if err != nil {
		wui.log.IfErr(err).Msg("unable to write Atom data")
	}
}

func (wui *WebUI) handleTagZettel(w http.ResponseWriter, r *http.Request, tagZettel *usecase.TagZettel, vals url.Values) bool {
	tag := vals.Get(api.QueryKeyTag)
	if tag == "" {
		return false
	}
	ctx := r.Context()
	z, err := tagZettel.Run(ctx, tag)
	if err != nil {
		wui.reportError(ctx, w, err)
		return true
	}
	wui.redirectFound(w, r, wui.NewURLBuilder('h').SetZid(api.ZettelID(z.Meta.Zid.String())))
	return true
}

		env, rb := wui.createRenderEnv(
			ctx, "rename",
			wui.rtConfig.Get(ctx, nil, api.KeyLang), "Rename Zettel "+m.Zid.String(), user)
		rb.bindString("incoming", wui.encodeIncoming(m, wui.makeGetTextTitle(ctx, getZettel)))
		wui.bindCommonZettelData(ctx, &rb, user, m, nil)
		if rb.err == nil {
			err = wui.renderSxnTemplate(ctx, w, id.RenameTemplateZid, env)
		} else {
			err = rb.err
		}
		if err != nil {
			wui.reportError(ctx, w, err)
		}
	}
}

	getMeta := func(ctx context.Context, zid id.Zid) (*meta.Meta, error) {
		z, err := wui.box.GetZettel(ctx, zid)
		if err != nil {
			return nil, err
		}
		return z.Meta, nil
	}
	dg := buildSxnCodeDigraph(ctx, id.StartSxnZid, getMeta)
	if dg == nil {
		return nil, wui.engine.RootEnvironment(), nil
	}
	dg = dg.AddVertex(id.BaseSxnZid).AddEdge(id.StartSxnZid, id.BaseSxnZid)
	dg = dg.AddVertex(id.PreludeSxnZid).AddEdge(id.BaseSxnZid, id.PreludeSxnZid)
	dg = dg.TransitiveClosure(id.StartSxnZid)

	if zid, isDAG := dg.IsDAG(); !isDAG {
		return nil, nil, fmt.Errorf("zettel %v is part of a dependency cycle", zid)
	}
	env := sxeval.MakeChildEnvironment(wui.engine.RootEnvironment(), "zettel", 128)
	for _, zid := range dg.SortReverse() {
		if err := wui.loadSxnCodeZettel(ctx, zid, env); err != nil {
			return nil, nil, err
		}
	}
	return dg, env, nil
}

type getMetaFunc func(context.Context, id.Zid) (*meta.Meta, error)

func buildSxnCodeDigraph(ctx context.Context, startZid id.Zid, getMeta getMetaFunc) id.Digraph {
	m, err := getMeta(ctx, startZid)
	if err != nil {
		return nil
	}
	var marked id.Set
	stack := []*meta.Meta{m}
	dg := id.Digraph(nil).AddVertex(startZid)
	for pos := len(stack) - 1; pos >= 0; pos = len(stack) - 1 {
		curr := stack[pos]
		stack = stack[:pos]
		if marked.Contains(curr.Zid) {
			continue
		}
		marked = marked.Add(curr.Zid)
		if precursors, hasPrecursor := curr.GetList(api.KeyPrecursor); hasPrecursor && len(precursors) > 0 {
			for _, pre := range precursors {
				if preZid, errParse := id.Parse(pre); errParse == nil {
					m, err = getMeta(ctx, preZid)
					if err != nil {
						continue
					}
					stack = append(stack, m)
					dg.AddVertex(preZid)
					dg.AddEdge(curr.Zid, preZid)
				}
			}
		}
	}


	return dg
}

func (wui *WebUI) loadSxnCodeZettel(ctx context.Context, zid id.Zid, env sxeval.Environment) error {
	rdr, err := wui.makeZettelReader(ctx, zid)
	if err != nil {
		return err
	}

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

func (wui *WebUI) createRenderEngine() *sxeval.Engine {
	root := sxeval.MakeRootEnvironment(len(syntaxes) + len(builtins) + 3)
	engine := sxeval.MakeEngine(wui.sf, root)


	for _, syntax := range syntaxes {
		engine.BindSyntax(syntax)
	}
	for _, b := range builtins {
		engine.BindBuiltin(b)
	}

	engine.BindBuiltin(&sxeval.Builtin{
		Name:     "url-to-html",
		MinArity: 1,
		MaxArity: 1,
		IsPure:   true,
		Fn: func(_ *sxeval.Frame, args []sx.Object) (sx.Object, error) {
			text, err := sxbuiltins.GetString(args, 0)
			if err != nil {
				return nil, err
			}
			return wui.url2html(text), nil
		},
	})
	engine.BindBuiltin(&sxeval.Builtin{
		Name:     "zid-content-path",
		MinArity: 1,
		MaxArity: 1,
		IsPure:   true,
		Fn: func(_ *sxeval.Frame, args []sx.Object) (sx.Object, error) {
			s, err := sxbuiltins.GetString(args, 0)
			if err != nil {
				return nil, err
			}
			zid, err := id.Parse(s.String())
			if err != nil {
				return nil, fmt.Errorf("parsing zettel identfier %q: %w", s, err)
			}
			ub := wui.NewURLBuilder('z').SetZid(api.ZettelID(zid.String()))
			return sx.String(ub.String()), nil
		},
	})
	engine.BindBuiltin(&sxeval.Builtin{
		Name:     "query->url",
		MinArity: 1,
		MaxArity: 1,
		IsPure:   true,
		Fn: func(_ *sxeval.Frame, args []sx.Object) (sx.Object, error) {
			qs, err := sxbuiltins.GetString(args, 0)
			if err != nil {
				return nil, err
			}
			u := wui.NewURLBuilder('h').AppendQuery(qs.String())
			return sx.String(u.String()), nil
		},
	})
	root.Freeze()
	return engine
}

var (
	syntaxes = []*sxeval.Syntax{
		&sxbuiltins.QuoteS, &sxbuiltins.QuasiquoteS, // quote, quasiquote
		&sxbuiltins.UnquoteS, &sxbuiltins.UnquoteSplicingS, // unquote, unquote-splicing

		&sxbuiltins.DefVarS, &sxbuiltins.DefConstS, // defvar, defconst
		&sxbuiltins.SetXS,                       // set!
		&sxbuiltins.DefineS,                     // define (DEPRECATED)
		&sxbuiltins.DefunS, &sxbuiltins.LambdaS, // defun, lambda
		&sxbuiltins.CondS,     // cond
		&sxbuiltins.IfS,       // if
		&sxbuiltins.DefMacroS, // defmacro
	}


	builtins = []*sxeval.Builtin{

		&sxbuiltins.Identical,            // ==
		&sxbuiltins.NullP,                // null?
		&sxbuiltins.PairP,                // pair?

		&sxbuiltins.Car, &sxbuiltins.Cdr, // car, cdr
		&sxbuiltins.Caar, &sxbuiltins.Cadr, &sxbuiltins.Cdar, &sxbuiltins.Cddr,
		&sxbuiltins.Caaar, &sxbuiltins.Caadr, &sxbuiltins.Cadar, &sxbuiltins.Caddr,
		&sxbuiltins.Cdaar, &sxbuiltins.Cdadr, &sxbuiltins.Cddar, &sxbuiltins.Cdddr,
		&sxbuiltins.List,         // list

		&sxbuiltins.Append,       // append
		&sxbuiltins.Assoc,        // assoc
		&sxbuiltins.Map,          // map
		&sxbuiltins.Apply,        // apply
		&sxbuiltins.StringAppend, // string-append
		&sxbuiltins.BoundP,       // bound?
		&sxbuiltins.Defined,      // defined?
		&sxbuiltins.CurrentEnv,   // current-environment
		&sxbuiltins.EnvLookup,    // environment-lookup
	}
)

func (wui *WebUI) url2html(text sx.String) sx.Object {





	if u, errURL := url.Parse(text.String()); errURL == nil {
		if us := u.String(); us != "" {
			return sx.MakeList(
				wui.symA,
				sx.MakeList(
					wui.symAttr,
					sx.Cons(wui.symHref, sx.String(us)),
					sx.Cons(wui.sf.MustMake("target"), sx.String("_blank")),
					sx.Cons(wui.sf.MustMake("rel"), sx.String("noopener noreferrer")),
				),
				text)
		}
	}
	return text
}























func (wui *WebUI) getParentEnv(ctx context.Context) (sxeval.Environment, error) {
	wui.mxZettelEnv.Lock()
	defer wui.mxZettelEnv.Unlock()
	if parentEnv := wui.zettelEnv; parentEnv != nil {
		return parentEnv, nil
	}
	dag, zettelEnv, err := wui.loadAllSxnCodeZettel(ctx)
	if err != nil {
		wui.log.Error().Err(err).Msg("loading zettel sxn")
		return nil, err
	}
	wui.dag = dag
	wui.zettelEnv = zettelEnv
	return zettelEnv, nil
}

// createRenderEnv creates a new environment and populates it with all relevant data for the base template.
func (wui *WebUI) createRenderEnv(ctx context.Context, name, lang, title string, user *meta.Meta) (sxeval.Environment, renderBinder) {
	userIsValid, userZettelURL, userIdent := wui.getUserRenderData(user)
	parentEnv, err := wui.getParentEnv(ctx)
	env := sxeval.MakeChildEnvironment(parentEnv, name, 128)
	rb := makeRenderBinder(wui.sf, env, err)
	rb.bindString("lang", sx.String(lang))
	rb.bindString("css-base-url", sx.String(wui.cssBaseURL))
	rb.bindString("css-user-url", sx.String(wui.cssUserURL))
	rb.bindString("title", sx.String(title))
	rb.bindString("home-url", sx.String(wui.homeURL))
	rb.bindString("with-auth", sx.MakeBoolean(wui.withAuth))
	rb.bindString("user-is-valid", sx.MakeBoolean(userIsValid))

func (wui *WebUI) bindCommonZettelData(ctx context.Context, rb *renderBinder, user, m *meta.Meta, content *zettel.Content) {
	strZid := m.Zid.String()
	apiZid := api.ZettelID(strZid)
	newURLBuilder := wui.NewURLBuilder

	rb.bindString("zid", sx.String(strZid))
	rb.bindString("web-url", sx.String(newURLBuilder('h').SetZid(apiZid).String()))
	if content != nil && wui.canWrite(ctx, user, m, *content) {
		rb.bindString("edit-url", sx.String(newURLBuilder('e').SetZid(apiZid).String()))
	}
	rb.bindString("info-url", sx.String(newURLBuilder('i').SetZid(apiZid).String()))
	if wui.canCreate(ctx, user) {
		if content != nil && !content.IsBinary() {
			rb.bindString("copy-url", sx.String(newURLBuilder('c').SetZid(apiZid).AppendKVQuery(queryKeyAction, valueActionCopy).String()))
		}
		rb.bindString("version-url", sx.String(newURLBuilder('c').SetZid(apiZid).AppendKVQuery(queryKeyAction, valueActionVersion).String()))
		rb.bindString("child-url", sx.String(newURLBuilder('c').SetZid(apiZid).AppendKVQuery(queryKeyAction, valueActionChild).String()))
		rb.bindString("folge-url", sx.String(newURLBuilder('c').SetZid(apiZid).AppendKVQuery(queryKeyAction, valueActionFolge).String()))
	}
	if wui.canRename(ctx, user, m) {
		rb.bindString("rename-url", sx.String(newURLBuilder('b').SetZid(apiZid).String()))
	}
	if wui.canDelete(ctx, user, m) {
		rb.bindString("delete-url", sx.String(newURLBuilder('d').SetZid(apiZid).String()))
	}
	if val, found := m.Get(api.KeyUselessFiles); found {
		rb.bindString("useless", sx.Cons(sx.String(val), nil))
	}
	rb.bindString("context-url", sx.String(newURLBuilder('h').AppendQuery(strZid+" "+api.ContextDirective).String()))
	if wui.canRefresh(user) {
		rb.bindString("reindex-url", sx.String(newURLBuilder('h').AppendQuery(strZid+" "+api.IdentDirective+api.ActionSeparator+"REINDEX").String()))
	}

	// Ensure to have title, role, tags, and syntax included as "meta-*"
	rb.bindKeyValue(api.KeyTitle, m.GetDefault(api.KeyTitle, ""))
	rb.bindKeyValue(api.KeyRole, m.GetDefault(api.KeyRole, ""))
	rb.bindKeyValue(api.KeyTags, m.GetDefault(api.KeyTags, ""))
	rb.bindKeyValue(api.KeySyntax, m.GetDefault(api.KeySyntax, ""))
	sentinel := sx.Cons(nil, nil)

		return nil, fmt.Errorf("expected 1 expression in template, but got %d", len(objs))
	}
	t, err := wui.engine.Parse(env, objs[0])
	if err != nil {
		return nil, err
	}

	wui.setSxnCache(zid, wui.engine.Rework(env, t))
	return t, nil
}
func (wui *WebUI) makeZettelReader(ctx context.Context, zid id.Zid) (*sxreader.Reader, error) {
	ztl, err := wui.box.GetZettel(ctx, zid)
	if err != nil {
		return nil, err
	}

	reader := sxreader.MakeReader(bytes.NewReader(ztl.Content.AsBytes()), sxreader.WithSymbolFactory(wui.sf))

	return reader, nil
}

func (wui *WebUI) evalSxnTemplate(ctx context.Context, zid id.Zid, env sxeval.Environment) (sx.Object, error) {
	templateExpr, err := wui.getSxnTemplate(ctx, zid, env)
	if err != nil {
		return nil, err

	user := server.GetUser(ctx)
	env, rb := wui.createRenderEnv(ctx, "error", api.ValueLangEN, "Error", user)
	rb.bindString("heading", sx.String(http.StatusText(code)))
	rb.bindString("message", sx.String(text))
	if rb.err == nil {
		rb.err = wui.renderSxnTemplateStatus(ctx, w, code, id.ErrorTemplateZid, env)
	}
	errSx := rb.err
	if errSx == nil {
		return
	}
	wui.log.Error().Err(errSx).Msg("while rendering error message")


	// if errBind != nil, the HTTP header was not written
	wui.prepareAndWriteHeader(w, http.StatusInternalServerError)
	fmt.Fprintf(
		w,
		`<!DOCTYPE html>
<html>
<head><title>Internal server error</title></head>
<body>
<h1>Internal server error</h1>
<p>When generating error code %d with message:</p><pre>%v</pre><p>an error occured:</p><pre>%v</pre>
</body>
</html>`, code, text, errSx)
}

func makeStringList(sl []string) *sx.Pair {
	if len(sl) == 0 {
		return nil
	}
	result := sx.Nil()
	for i := len(sl) - 1; i >= 0; i-- {
		result = result.Cons(sx.String(sl[i]))
	}
	return result
}

	sf          sx.SymbolFactory
	engine      *sxeval.Engine
	mxZettelEnv sync.Mutex
	zettelEnv   sxeval.Environment
	dag         id.Digraph
	genHTML     *sxhtml.Generator



	symMetaHeader *sx.Symbol
	symDetail     *sx.Symbol
	symA, symHref *sx.Symbol
	symSpan       *sx.Symbol
	symAttr       *sx.Symbol
}

// webuiBox contains all box methods that are needed for WebUI operation.
//
// Note: these function must not do auth checking.
type webuiBox interface {
	CanCreateZettel(context.Context) bool

		logoutURL:     loginoutBase.AppendKVQuery("logout", "").String(),
		searchURL:     ab.NewURLBuilder('h').String(),
		createNewURL:  ab.NewURLBuilder('c').String(),

		sf:            sf,
		zettelEnv:     nil,
		genHTML:       sxhtml.NewGenerator(sf, sxhtml.WithNewline),




		symDetail:     sf.MustMake("DETAIL"),
		symMetaHeader: sf.MustMake("META-HEADER"),
		symA:          sf.MustMake("a"),
		symHref:       sf.MustMake("href"),
		symSpan:       sf.MustMake("span"),
		symAttr:       sf.MustMake(sxhtml.NameSymAttr),
	}

<title>Change Log</title>

<a id="0_16"></a>
<h2>Changes for Version 0.16.0 (pending)</h2>

<a id="0_15"></a>
<h2>Changes for Version 0.15.0 (2023-10-26)</h2>
  *  Sx function <tt>define</tt> is now deprecated. It will be removed in
     version 0.16. Use <tt>defvar</tt> or <tt>defun</tt> instead. Otherwise
     the WebUI will not work in version 0.16.
     (major: webui, deprecated)
  *  Zettel can be re-indexed via WebUI or API query action <tt>REINDEX</tt>.
     The info page of a zettel contains a link to re-index the zettel. In
     a query transclusion, this action is ignored.
     (major: api, webui).
  *  Allow to determine a tag zettel for a given tag.
     (major: api, webui)
  *  Present user the option to create a (missing) tag zettel (in list view).
     Results in a new predefined zettel with identifier 00000000090003, which
     is a template for new tag zettel.
     (minor: webui)
  *  ZIP file with manual now contains a zettel 00001000000000 that contains
     its build date (metadata key <tt>created</tt>) and version (in the zettel
     content)
     (minor)
  *  If an error page cannot be created due to template errors (or similar), a
     plain text error page is delivered instead. It shows the original error
     and the error that occured durng rendering the original error page.
     (minor: webui)
  *  Some smaller bug fixes and improvements, to the software and to the
     documentation.

<a id="0_14"></a>
<h2>Changes for Version 0.14.0 (2023-09-22)</h2>
  *  Remove support for JSON. This was marked deprecated in version 0.12.0. Use
     the <tt>data</tt> encoding instead, a form of symbolic expressions.
     (breaking: api; minor: webui)
  *  Remove deprecated syntax for a context list: <tt>CONTEXT zid</tt>. Use

<title>Download</title>
<h1>Download of Zettelstore Software</h1>
<h2>Foreword</h2>
  *  Zettelstore is free/libre open source software, licensed under EUPL-1.2-or-later.
  *  The software is provided as-is.
  *  There is no guarantee that it will not damage your system.
  *  However, it is in use by the main developer since March 2020 without any damage.
  *  It may be useful for you. It is useful for me.
  *  Take a look at the [https://zettelstore.de/manual/|manual] to know how to start and use it.

<h2>ZIP-ped Executables</h2>
Build: <code>v0.15.0</code> (2023-10-26).

  *  [/uv/zettelstore-0.15.0-linux-amd64.zip|Linux] (amd64)
  *  [/uv/zettelstore-0.15.0-linux-arm.zip|Linux] (arm6, e.g. Raspberry Pi)
  *  [/uv/zettelstore-0.15.0-darwin-arm64.zip|macOS] (arm64)
  *  [/uv/zettelstore-0.15.0-darwin-amd64.zip|macOS] (amd64)
  *  [/uv/zettelstore-0.15.0-windows-amd64.zip|Windows] (amd64)

Unzip the appropriate file, install and execute Zettelstore according to the manual.

<h2>Zettel for the manual</h2>
As a starter, you can download the zettel for the manual
[/uv/manual-0.15.0.zip|here].
Just unzip the contained files and put them into your zettel folder or
configure a file box to read the zettel directly from the ZIP file.

     software, which often connects to Zettelstore via its API. Some of the
     software packages may be experimental.
  *  [https://zettelstore.de/sx|Sx] provides an evaluator for symbolic
     expressions, which is unsed for HTML templates and more.

[https://mastodon.social/tags/Zettelstore|Stay tuned] …
<hr>
<h3>Latest Release: 0.15.0 (2023-10-26)</h3>
  *  [./download.wiki|Download]
  *  [./changes.wiki#0_15|Change summary]
  *  [/timeline?p=v0.15.0&bt=v0.14.0&y=ci|Check-ins for version 0.15.0],
     [/vdiff?to=v0.15.0&from=v0.14.0|content diff]
  *  [/timeline?df=v0.15.0&y=ci|Check-ins derived from the 0.15.0 release],
     [/vdiff?from=v0.15.0&to=trunk|content diff]
  *  [./plan.wiki|Limitations and planned improvements]
  *  [/timeline?t=release|Timeline of all past releases]

<hr>
<h2>Build instructions</h2>
Just install [https://go.dev/dl/|Go] and some Go-based tools. Please read
the [./build.md|instructions] for details.

  *  [/dir?ci=trunk|Source code]
  *  [/download|Download the source code] as a tarball or a ZIP file
     (you must [/login|login] as user &quot;anonymous&quot;).

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

package id

import (
	"maps"
	"slices"
)

// Digraph relates zettel identifier in a directional way.
type Digraph map[Zid]Set

// AddVertex adds an edge / vertex to the digraph.
func (dg Digraph) AddVertex(zid Zid) Digraph {
	if dg == nil {
		return Digraph{zid: nil}
	}
	if _, found := dg[zid]; !found {
		dg[zid] = nil
	}
	return dg
}

// RemoveVertex removes a vertex and all its edges from the digraph.
func (dg Digraph) RemoveVertex(zid Zid) {
	if len(dg) > 0 {
		delete(dg, zid)
		for vertex, closure := range dg {
			dg[vertex] = closure.Remove(zid)
		}
	}
}

// AddEdge adds a connection from `zid1` to `zid2`.
// Both vertices must be added before. Otherwise the function may panic.
func (dg Digraph) AddEdge(fromZid, toZid Zid) Digraph {
	if dg == nil {
		return Digraph{fromZid: Set(nil).Add(toZid), toZid: nil}
	}

	return dg
}

// Equal returns true if both digraphs have the same vertices and edges.
func (dg Digraph) Equal(other Digraph) bool {
	return maps.EqualFunc(dg, other, func(cg, co Set) bool { return cg.Equal(co) })
}

// Clone a digraph.
func (dg Digraph) Clone() Digraph {
	if len(dg) == 0 {
		return nil
	}
	copyDG := make(Digraph, len(dg))
	for vertex, closure := range dg {
		copyDG[vertex] = closure.Clone()
	}
	return copyDG
}

// HasVertex returns true, if `zid` is a vertex of the digraph.
func (dg Digraph) HasVertex(zid Zid) bool {
	if len(dg) == 0 {
		return false
	}
	_, found := dg[zid]

	for vertex := range dg {
		if dg.ReachableVertices(vertex).Contains(vertex) {
			return vertex, false
		}
	}
	return Invalid, true
}

// Reverse returns a graph with reversed edges.
func (dg Digraph) Reverse() (revDg Digraph) {
	for vertex, closure := range dg {
		revDg = revDg.AddVertex(vertex)
		for next := range closure {
			revDg = revDg.AddVertex(next)
			revDg = revDg.AddEdge(next, vertex)
		}
	}
	return revDg
}

// SortReverse returns a deterministic, topological, reverse sort of the
// digraph.
//
// Works only if digraph is a DAG. Otherwise the algorithm will not terminate
// or returns an arbitrary value.
func (dg Digraph) SortReverse() (sl Slice) {
	if len(dg) == 0 {
		return nil
	}

	tempDg := dg.Clone()

	for len(tempDg) > 0 {
		terms := tempDg.Terminators()
		if len(terms) == 0 {
			break


		}


		termSlice := terms.Sorted()
		slices.Reverse(termSlice)
		sl = append(sl, termSlice...)
		for t := range terms {

			tempDg.RemoveVertex(t)

		}


	}
	return sl
}

	for _, tc := range testcases {
		t.Run(tc.name, func(t *testing.T) {
			dg := createDigraph(tc.pairs)
			if got := dg.TransitiveClosure(tc.start).Edges().Sort(); !got.Equal(tc.exp) {
				t.Errorf("\n%v, but got:\n%v", tc.exp, got)
			}

		})
	}
}

func TestIsDAG(t *testing.T) {
	t.Parallel()
	testcases := []struct {

		t.Run(tc.name, func(t *testing.T) {
			if zid, got := createDigraph(tc.dg).IsDAG(); got != tc.exp {
				t.Errorf("expected %v, but got %v (%v)", tc.exp, got, zid)
			}
		})
	}
}

func TestDigraphReverse(t *testing.T) {
	t.Parallel()
	testcases := []struct {
		name string
		dg   id.EdgeSlice
		exp  id.EdgeSlice
	}{
		{"empty", nil, nil},
		{"single-edge", zps{{1, 2}}, zps{{2, 1}}},
		{"single-loop", zps{{1, 1}}, zps{{1, 1}}},
		{"end-loop", zps{{1, 2}, {2, 2}}, zps{{2, 1}, {2, 2}}},
		{"long-loop", zps{{1, 2}, {2, 3}, {3, 4}, {4, 5}, {5, 2}}, zps{{2, 1}, {2, 5}, {3, 2}, {4, 3}, {5, 4}}},
		{"sect-loop", zps{{1, 2}, {2, 3}, {3, 4}, {4, 5}, {4, 2}}, zps{{2, 1}, {2, 4}, {3, 2}, {4, 3}, {5, 4}}},
		{"two-islands", zps{{1, 2}, {2, 3}, {4, 5}}, zps{{2, 1}, {3, 2}, {5, 4}}},
		{"direct-indirect", zps{{1, 2}, {1, 3}, {3, 2}}, zps{{2, 1}, {2, 3}, {3, 1}}},
	}
	for _, tc := range testcases {
		t.Run(tc.name, func(t *testing.T) {
			dg := createDigraph(tc.dg)
			if got := dg.Reverse().Edges().Sort(); !got.Equal(tc.exp) {
				t.Errorf("\n%v, but got:\n%v", tc.exp, got)
			}
		})
	}
}

func TestDigraphSortReverse(t *testing.T) {
	t.Parallel()
	testcases := []struct {
		name string
		dg   id.EdgeSlice
		exp  id.Slice
	}{
		{"empty", nil, nil},
		{"single-edge", zps{{1, 2}}, id.Slice{2, 1}},
		{"single-loop", zps{{1, 1}}, nil},
		{"end-loop", zps{{1, 2}, {2, 2}}, id.Slice{}},
		{"long-loop", zps{{1, 2}, {2, 3}, {3, 4}, {4, 5}, {5, 2}}, id.Slice{}},
		{"sect-loop", zps{{1, 2}, {2, 3}, {3, 4}, {4, 5}, {4, 2}}, id.Slice{5}},
		{"two-islands", zps{{1, 2}, {2, 3}, {4, 5}}, id.Slice{5, 3, 4, 2, 1}},
		{"direct-indirect", zps{{1, 2}, {1, 3}, {3, 2}}, id.Slice{2, 3, 1}},
	}
	for _, tc := range testcases {
		t.Run(tc.name, func(t *testing.T) {
			if got := createDigraph(tc.dg).SortReverse(); !got.Equal(tc.exp) {
				t.Errorf("expected:\n%v, but got:\n%v", tc.exp, got)
			}
		})
	}
}

	InfoTemplateZid   = MustParse(api.ZidInfoTemplate)
	FormTemplateZid   = MustParse(api.ZidFormTemplate)
	RenameTemplateZid = MustParse(api.ZidRenameTemplate)
	DeleteTemplateZid = MustParse(api.ZidDeleteTemplate)
	ErrorTemplateZid  = MustParse(api.ZidErrorTemplate)
	StartSxnZid       = MustParse(api.ZidSxnStart)
	BaseSxnZid        = MustParse(api.ZidSxnBase)
	PreludeSxnZid     = MustParse(api.ZidSxnPrelude)
	EmojiZid          = MustParse(api.ZidEmoji)
	TOCNewTemplateZid = MustParse(api.ZidTOCNewTemplate)
	DefaultHomeZid    = MustParse(api.ZidDefaultHome)
)

const maxZid = 99999999999999

	}
	return true
}

// Copy adds all member from the other set.
func (s Set) Copy(other Set) Set {
	if s == nil {
		if len(other) == 0 {
			return nil
		}
		s = NewSetCap(len(other))
	}
	maps.Copy(s, other)
	return s
}

// CopySlice adds all identifier of the given slice to the set.
func (s Set) CopySlice(sl Slice) Set {
	if s == nil {
		s = NewSetCap(len(sl))
	}
	for _, zid := range sl {
		s[zid] = struct{}{}
	}
	return s
}

// 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 {

// under this license.
//-----------------------------------------------------------------------------

package meta

import (
	"fmt"
	"strings"

	"zettelstore.de/client.fossil/api"
)

// Supported syntax values.
const (
	SyntaxCSS      = api.ValueSyntaxCSS

// GetUserRole role returns the user role of the given string.
func GetUserRole(val string) UserRole {
	if ur, ok := urMap[val]; ok {
		return ur
	}
	return UserRoleUnknown
}

// NormalizeTag adds a missing prefix "#" to the tag
func NormalizeTag(tag string) string {
	if strings.HasPrefix(tag, "#") {
		return tag
	}
	return "#" + tag
}