# To get started with Dependabot version updates, you'll need to specify which
# package ecosystems to update and where the package manifests are located.
# Please see the documentation for all configuration options:
# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates

version: 2
updates:
  - package-ecosystem: "gomod" # See documentation for possible values
    directory: "/" # Location of package manifests
    schedule:
      interval: "daily"
    rebase-strategy: "disabled"

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

// Package api contains common definitions used for client and server.
package api

// ZettelID contains the identifier of a zettel. It is a string with 14 digits.
type ZettelID string

// InvalidZID is an invalif zettel identifier
// InvalidZID is an invalid zettel identifier
const InvalidZID = ""

// IsValid returns true, if the idenfifier contains 14 digits.
func (zid ZettelID) IsValid() bool {
	if len(zid) != 14 {
		return false
	}
	for i := 0; i < 14; i++ {
	for i := range 14 {
		ch := zid[i]
		if ch < '0' || '9' < ch {
			return false
		}
	}
	return true
}

// ZettelMeta is a map containg the metadata of a zettel.
// ZettelMeta is a map containg the normalized metadata of a zettel.
type ZettelMeta map[string]string

// ZettelRights is an integer that encode access rights for a zettel.
type ZettelRights uint8

// Values for ZettelRights, can be or-ed
const (
	ZettelCanNone   ZettelRights = 1 << iota
	ZettelCanCreate              // Current user is allowed to create a new zettel
	ZettelCanRead                // Requesting user is allowed to read the zettel
	ZettelCanWrite               // Requesting user is allowed to update the zettel
	ZettelCanRename              // Requesting user is allowed to provide the zettel with a new identifier
	placeholdergo1               // Was assigned to rename right, which is now removed
	ZettelCanDelete              // Requesting user is allowed to delete the zettel
	ZettelMaxRight               // Sentinel value
)

// MetaRights contains the metadata of a zettel, and its rights.
type MetaRights struct {
	Meta   ZettelMeta
	Rights ZettelRights
}

// ZidMetaRights contains the identifier, the metadata of a zettel, and its rights.
type ZidMetaRights struct {
	ID     ZettelID
	Meta   ZettelMeta
	Rights ZettelRights
}

// ZettelData contains all data for a zettel.
//
//   - Meta is a map containing the metadata of the zettel.
//   - Rights is an integer specifying the access rights.
//   - Encoding is a string specifying the encoding of the zettel content.
//   - Content is the zettel content itself.
type ZettelData struct {
	Meta     ZettelMeta
	Rights   ZettelRights
	Encoding string
	Content  string
	Content  string // raw, uninterpreted zettel content
}

// Aggregate maps metadata keys to list of zettel identifier.
type Aggregate map[string][]ZettelID

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

package api

import "fmt"

// Predefined Zettel Identifier
// Predefined zettel identifier.
//
// See [List of predefined zettel].
//
// [List of predefined zettel]: https://zettelstore.de/manual/h/00001005090000
const (
	// System zettel
	ZidVersion              = ZettelID("00000000000001")
	ZidHost                 = ZettelID("00000000000002")
	ZidOperatingSystem      = ZettelID("00000000000003")
	ZidLicense              = ZettelID("00000000000004")
	ZidAuthors              = ZettelID("00000000000005")
	ZidDependencies         = ZettelID("00000000000006")
	ZidLog                  = ZettelID("00000000000007")
	ZidMemory               = ZettelID("00000000000008")
	ZidSx                   = ZettelID("00000000000009")
	ZidHTTP                 = ZettelID("00000000000010")
	ZidAPI                  = ZettelID("00000000000011")
	ZidWebUI                = ZettelID("00000000000012")
	ZidConsole              = ZettelID("00000000000013")
	ZidBoxManager           = ZettelID("00000000000020")
	ZidZettel               = ZettelID("00000000000021")
	ZidIndex                = ZettelID("00000000000022")
	ZidQuery                = ZettelID("00000000000023")
	ZidMetadataKey          = ZettelID("00000000000090")
	ZidParser               = ZettelID("00000000000092")
	ZidStartupConfiguration = ZettelID("00000000000096")
	ZidConfiguration        = ZettelID("00000000000100")
	ZidDirectory            = ZettelID("00000000000101")

	// WebUI HTML templates are in the range 10000..19999
	ZidBaseTemplate   = ZettelID("00000000010100")
	ZidLoginTemplate  = ZettelID("00000000010200")
	ZidListTemplate   = ZettelID("00000000010300")
	ZidZettelTemplate = ZettelID("00000000010401")
	ZidInfoTemplate   = ZettelID("00000000010402")
	ZidFormTemplate   = ZettelID("00000000010403")
	ZidRenameTemplate = ZettelID("00000000010404")
	ZidDeleteTemplate = ZettelID("00000000010405")
	ZidErrorTemplate  = ZettelID("00000000010700")

	// WebUI sxn code zettel are in the range 19000..19999
	ZidSxnTemplate = ZettelID("00000000019100")
	ZidSxnStart = ZettelID("00000000019000")
	ZidSxnBase  = ZettelID("00000000019990")

	// CSS-related zettel are in the range 20000..29999
	ZidBaseCSS    = ZettelID("00000000020001")
	ZidUserCSS    = ZettelID("00000000025001")
	ZidBaseCSS = ZettelID("00000000020001")
	ZidUserCSS = ZettelID("00000000025001")
	ZidRoleCSSMap = ZettelID("00000000029000") // Maps roles to CSS zettel, which should be in the range 29001..29999.

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

	// WebUI image zettel are in the range 40000..49999
	ZidEmoji = ZettelID("00000000040001")

	// Other sxn code zettel are in the range 50000..59999
	ZidSxnPrelude = ZettelID("00000000059900")

	// Predefined Zettelmarkup zettel are in the range 60000..69999
	ZidRoleZettelZettel        = ZettelID("00000000060010")
	ZidRoleConfigurationZettel = ZettelID("00000000060020")
	ZidRoleRoleZettel          = ZettelID("00000000060030")
	ZidRoleTagZettel           = ZettelID("00000000060040")

	// Range 80000...89999 is reserved for web ui menus
	ZidTOCListsMenu = ZettelID("00000000080001") // "Lists" menu

	// Range 90000...99999 is reserved for zettel templates
	ZidTOCNewTemplate    = ZettelID("00000000090000")
	ZidTemplateNewZettel = ZettelID("00000000090001")
	ZidTemplateNewRole   = ZettelID("00000000090004")
	ZidTemplateNewTag    = ZettelID("00000000090003")
	ZidTemplateNewUser   = ZettelID("00000000090002")

	// Range 00000999999900...00000999999999 are predefined zettel to be searched by content.
	ZidAppDirectory = ZettelID("00000999999999")

	// Default Home Zettel
	ZidDefaultHome = ZettelID("00010000000000")
)

// LengthZid factors the constant length of a zettel identifier
const LengthZid = len(ZidDefaultHome)

// Values of the metadata key/value type.
// Values of the metadata key/value types.
//
// See [Supported Key Types].
//
// [Supported Key Types]: https://zettelstore.de/manual/h/00001006030000
const (
	MetaCredential   = "Credential"
	MetaEmpty        = "EString"
	MetaID           = "Identifier"
	MetaIDSet        = "IdentifierSet"
	MetaNumber       = "Number"
	MetaString       = "String"
	MetaTagSet       = "TagSet"
	MetaTimestamp    = "Timestamp"
	MetaURL          = "URL"
	MetaWord         = "Word"
	MetaWordSet      = "WordSet"
	MetaZettelmarkup = "Zettelmarkup"
)

// Predefined general Metadata keys
// Predefined / supported metadata keys.
//
// See [Supported Metadata Keys].
//
// [Supported Metadata Keys]: https://zettelstore.de/manual/h/00001006020000
const (
	KeyID           = "id"
	KeyTitle        = "title"
	KeyRole         = "role"
	KeyTags         = "tags"
	KeySyntax       = "syntax"
	KeyAuthor       = "author"

	KeyFolgeRole    = "folge-role"
	KeyForward      = "forward"
	KeyLang         = "lang"
	KeyLicense      = "license"
	KeyModified     = "modified"
	KeyPrecursor    = "precursor"
	KeyPredecessor  = "predecessor"
	KeyPrequel      = "prequel"
	KeyPublished    = "published"
	KeyQuery        = "query"
	KeyReadOnly     = "read-only"
	KeySequel       = "sequel"
	KeySubordinates = "subordinates"
	KeySuccessors   = "successors"
	KeySuperior     = "superior"
	KeySummary      = "summary"
	KeySuperior     = "superior"
	KeyURL          = "url"
	KeyUselessFiles = "useless-files"
	KeyUserID       = "user-id"
	KeyUserRole     = "user-role"
	KeyVisibility   = "visibility"
)

// Predefined Metadata values
// Predefined metadata values.
const (
	ValueFalse             = "false"
	ValueTrue              = "true"
	ValueLangEN            = "en"
	ValueRoleConfiguration = "configuration"
	ValueRoleZettel        = "zettel"
	ValueSyntaxCSS         = "css"
	ValueSyntaxDraw        = "draw"
	ValueSyntaxGif         = "gif"
	ValueSyntaxHTML        = "html"
	ValueSyntaxMarkdown    = "markdown"
	ValueSyntaxMD          = "md"
	ValueSyntaxNone        = "none"
	ValueSyntaxSVG         = "svg"
	ValueSyntaxSxn         = "sxn"
	ValueSyntaxText        = "text"
	ValueSyntaxZmk         = "zmk"
	ValueLangEN            = "en"            // Default for "lang"
	ValueRoleConfiguration = "configuration" // A role for internal zettel
	ValueRoleTag           = "tag"           // A role for tag zettel
	ValueRoleRole          = "role"          // A role for role zettel
	ValueRoleZettel        = "zettel"        // A role for zettel
	ValueSyntaxCSS         = "css"           // Syntax: CSS
	ValueSyntaxDraw        = "draw"          // Syntax: Drawing
	ValueSyntaxGif         = "gif"           // Syntax GIF image
	ValueSyntaxHTML        = "html"          // Syntax: HTML
	ValueSyntaxMarkdown    = "markdown"      // Syntax: Markdown / CommonMark
	ValueSyntaxMD          = "md"            // Syntax: Markdown / CommonMark
	ValueSyntaxNone        = "none"          // Syntax: no syntax / content, just metadata
	ValueSyntaxSVG         = "svg"           // Syntax: SVG
	ValueSyntaxSxn         = "sxn"           // Syntax: S-Expression
	ValueSyntaxText        = "text"          // Syntax: plain text
	ValueSyntaxZmk         = "zmk"           // Syntax: Zettelmarkup
	ValueUserRoleCreator   = "creator"
	ValueUserRoleOwner     = "owner"
	ValueUserRoleReader    = "reader"
	ValueUserRoleWriter    = "writer"
	ValueVisibilityCreator = "creator"
	ValueVisibilityExpert  = "expert"
	ValueVisibilityLogin   = "login"
	ValueVisibilityOwner   = "owner"
	ValueVisibilityPublic  = "public"
)

// Additional HTTP constants.
const (
	MethodMove = "MOVE" // HTTP method for renaming a zettel

	HeaderAccept      = "Accept"
	HeaderContentType = "Content-Type"
	HeaderDestination = "Destination"
	HeaderLocation    = "Location"
)

// Values for HTTP query parameter.
const (
	QueryKeyCommand   = "cmd"
	QueryKeyEncoding  = "enc"
	QueryKeyParseOnly = "parseonly"
	QueryKeyPart      = "part"
	QueryKeyPhrase    = "phrase"
	QueryKeyQuery     = "q"
	QueryKeyRole      = "role"
	QueryKeySeed      = "_seed"
	QueryKeyTag       = "tag"
)

// Supported encoding values.
const (
	EncodingHTML  = "html"
	EncodingMD    = "md"
	EncodingSHTML = "shtml"
	EncodingSz    = "sz"
	EncodingText  = "text"
	EncodingZMK   = "zmk"
	EncodingHTML  = "html"  // Plain HTML
	EncodingMD    = "md"    // Markdown
	EncodingSHTML = "shtml" // SxHTML
	EncodingSz    = "sz"    // Structure of zettel, encoded a an S-expression
	EncodingText  = "text"  // plain text content
	EncodingZMK   = "zmk"   // Zettelmarkup

	EncodingPlain = "plain"
	EncodingData  = "data"
	EncodingPlain = "plain" // Plain zettel, no processing
	EncodingData  = "data"  // Plain zettel, metadata as S-Expression
	EncodingJson  = "json"
)

var mapEncodingEnum = map[string]EncodingEnum{
	EncodingHTML:  EncoderHTML,
	EncodingMD:    EncoderMD,
	EncodingSHTML: EncoderSHTML,
	EncodingSz:    EncoderSz,
	EncodingText:  EncoderText,
	EncodingZMK:   EncoderZmk,

	EncodingPlain: EncoderPlain,
	EncodingData:  EncoderData,
	EncodingJson:  EncoderJson,
}
var mapEnumEncoding = map[EncodingEnum]string{}

func init() {
	for k, v := range mapEncodingEnum {
		mapEnumEncoding[v] = k
	}

	EncoderSHTML
	EncoderSz
	EncoderText
	EncoderZmk

	EncoderPlain
	EncoderData
	EncoderJson
)

// String representation of an encoder key.
func (e EncodingEnum) String() string {
	if f, ok := mapEnumEncoding[e]; ok {
		return f
	}
	return fmt.Sprintf("*Unknown*(%d)", e)
}

// Supported part values.
const (
	PartMeta    = "meta"
	PartContent = "content"
	PartZettel  = "zettel"
)

// Command to be executed atthe Zettelstore
type Command string

// Supported command values
// Supported command values.
const (
	CommandAuthenticated = Command("authenticated")
	CommandRefresh       = Command("refresh")
)

// Supported search operator representations
// Supported search operator representations.
const (
	BackwardDirective = "BACKWARD"
	ContextDirective  = "CONTEXT"
	CostDirective     = "COST"
	ForwardDirective  = "FORWARD"
	IdentDirective    = "IDENT"
	ItemsDirective    = "ITEMS"
	MaxDirective      = "MAX"
	LimitDirective    = "LIMIT"
	OffsetDirective   = "OFFSET"
	OrDirective       = "OR"
	OrderDirective    = "ORDER"
	PhraseDirective   = "PHRASE"
	PickDirective     = "PICK"
	RandomDirective   = "RANDOM"
	ReverseDirective  = "REVERSE"
	UnlinkedDirective = "UNLINKED"
	BackwardDirective = "BACKWARD" // Backward-only context
	ContextDirective  = "CONTEXT"  // Context directive
	CostDirective     = "COST"     // Maximum cost of a context operation
	ForwardDirective  = "FORWARD"  // Forward-only context
	FullDirective     = "FULL"     // Include tags in context
	IdentDirective    = "IDENT"    // Use only specified zettel
	ItemsDirective    = "ITEMS"    // Select list elements in a zettel
	MaxDirective      = "MAX"      // Maximum number of context results
	LimitDirective    = "LIMIT"    // Maximum number of zettel
	OffsetDirective   = "OFFSET"   // Offset to start returned zettel list
	OrDirective       = "OR"       // Combine several search expression with an "or"
	OrderDirective    = "ORDER"    // Specify metadata keys for the order of returned list
	PhraseDirective   = "PHRASE"   // Only unlinked zettel with given phrase
	PickDirective     = "PICK"     // Pick some random zettel
	RandomDirective   = "RANDOM"   // Order zettel list randomly
	ReverseDirective  = "REVERSE"  // Reverse the order of a zettel list
	UnlinkedDirective = "UNLINKED" // Search for zettel that contain a phase(s) but do not link

	ActionSeparator = "|"
	ActionSeparator = "|" // Separates action list of previous elements of query expression

	KeysAction     = "KEYS"     // Provide metadata key used
	MinAction      = "MIN"      // Return only those values with a minimum amount of zettel
	MaxAction      = "MAX"      // Return only those values with a maximum amount of zettel
	NumberedAction = "NUMBERED" // Return a numbered list
	RedirectAction = "REDIRECT" // Return the first zettel in list
	ReIndexAction  = "REINDEX"  // Ensure that zettel is/are indexed.

	ExistOperator    = "?"
	ExistNotOperator = "!?"
	ExistOperator    = "?"  // Does zettel have metadata with given key?
	ExistNotOperator = "!?" // True id zettel does not have metadata with given key.

	SearchOperatorNot        = "!"
	SearchOperatorEqual      = "="
	SearchOperatorNotEqual   = "!="
	SearchOperatorHas        = ":"
	SearchOperatorHasNot     = "!:"
	SearchOperatorPrefix     = "["
	SearchOperatorNoPrefix   = "!["
	SearchOperatorSuffix     = "]"
	SearchOperatorNoSuffix   = "!]"
	SearchOperatorMatch      = "~"
	SearchOperatorNoMatch    = "!~"
	SearchOperatorLess       = "<"
	SearchOperatorNotLess    = "!<"
	SearchOperatorGreater    = ">"
	SearchOperatorNotGreater = "!>"
	SearchOperatorEqual      = "="  // True if values are equal
	SearchOperatorNotEqual   = "!=" // False if values are equal
	SearchOperatorHas        = ":"  // True if values are equal/included
	SearchOperatorHasNot     = "!:" // False if values are equal/included
	SearchOperatorPrefix     = "["  // True if value is prefix of the other
	SearchOperatorNoPrefix   = "![" // False if value is prefix of the other
	SearchOperatorSuffix     = "]"  // True if value is suffix of other
	SearchOperatorNoSuffix   = "!]" // False if value is suffix of other
	SearchOperatorMatch      = "~"  // True if value is included in other
	SearchOperatorNoMatch    = "!~" // False if value is included in other
	SearchOperatorLess       = "<"  // True if value is smaller than other
	SearchOperatorNotLess    = "!<" // False if value is smaller than other
	SearchOperatorGreater    = ">"  // True if value is greater than other
	SearchOperatorNotGreater = "!>" // False if value is greater than other
)

// QueryPrefix is the prefix that denotes a query expression within a reference.
const QueryPrefix = "query:"

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

package api

import (
import "t73f.de/r/webs/urlbuilder"
	"net/url"
	"strings"
)

type urlQuery struct{ key, val string }

// URLBuilder should be used to create zettelstore URLs.
type URLBuilder struct {
	base   urlbuilder.URLBuilder
	prefix   string
	prefix string
	key      byte
	rawLocal string
	path     []string
	query    []urlQuery
	fragment string
}

// NewURLBuilder creates a new URL builder with the given prefix and key.
func NewURLBuilder(prefix string, key byte) *URLBuilder {
	for len(prefix) > 0 && prefix[len(prefix)-1] == '/' {
	return &URLBuilder{prefix: prefix, key: key}
}
		prefix = prefix[0 : len(prefix)-1]
	}

// Clone an URLBuilder
	result := URLBuilder{prefix: prefix}
func (ub *URLBuilder) Clone() *URLBuilder {
	cpy := new(URLBuilder)
	cpy.key = ub.key
	if len(ub.path) > 0 {
	if key != '/' {
		result.base.AddPath(string([]byte{key}))
		cpy.path = make([]string, 0, len(ub.path))
		cpy.path = append(cpy.path, ub.path...)
	}
	if len(ub.query) > 0 {
		cpy.query = make([]urlQuery, 0, len(ub.query))
		cpy.query = append(cpy.query, ub.query...)
	}
	cpy.fragment = ub.fragment
	return cpy
	return &result
}

// SetRawLocal sets everything that follows the prefix / key.
func (ub *URLBuilder) SetRawLocal(rawLocal string) *URLBuilder {
// Clone an URLBuilder.
func (ub *URLBuilder) Clone() *URLBuilder {
	for len(rawLocal) > 0 && rawLocal[0] == '/' {
		rawLocal = rawLocal[1:]
	}
	ub.rawLocal = rawLocal
	ub.path = nil
	ub.query = nil
	ub.fragment = ""
	return ub
	cpy := new(URLBuilder)
	ub.base.Copy(&cpy.base)
	cpy.prefix = ub.prefix
	return cpy
}

// SetZid sets the zettel identifier.
func (ub *URLBuilder) SetZid(zid ZettelID) *URLBuilder {
	if len(ub.path) > 0 {
		panic("Cannot add Zid")
	}
	ub.rawLocal = ""
	ub.path = append(ub.path, string(zid))
	ub.base.AddPath(string(zid))
	return ub
}

// AppendPath adds a new path element
// AppendPath adds a new path element.
func (ub *URLBuilder) AppendPath(p string) *URLBuilder {
	ub.rawLocal = ""
	ub.base.AddPath(p)
	for len(p) > 0 && p[0] == '/' {
		p = p[1:]
	}
	if p != "" {
		ub.path = append(ub.path, p)
	}
	return ub
}

// AppendKVQuery adds a new key/value query parameter
// AppendKVQuery adds a new key/value query parameter.
func (ub *URLBuilder) AppendKVQuery(key, value string) *URLBuilder {
	ub.rawLocal = ""
	ub.query = append(ub.query, urlQuery{key, value})
	ub.base.AddQuery(key, value)
	return ub
}

// AppendQuery adds a new query
// AppendQuery adds a new query.
//
// Basically the same as [URLBuilder.AppendKVQuery]([api.QueryKeyQuery], value)
func (ub *URLBuilder) AppendQuery(value string) *URLBuilder {
	if value != "" {
		ub.rawLocal = ""
		ub.query = append(ub.query, urlQuery{QueryKeyQuery, value})
		ub.base.AddQuery(QueryKeyQuery, value)
	}
	return ub
}

// ClearQuery removes all query parameters.
func (ub *URLBuilder) ClearQuery() *URLBuilder {
	ub.rawLocal = ""
	ub.query = nil
	ub.base.RemoveQueries()
	ub.fragment = ""
	return ub
}

// SetFragment stores the fragment
// SetFragment sets the fragment.
func (ub *URLBuilder) SetFragment(s string) *URLBuilder {
	ub.rawLocal = ""
	ub.fragment = s
	ub.base.SetFragment(s)
	return ub
}

// String produces a string value.
func (ub *URLBuilder) String() string {
	var sb strings.Builder

	return ub.prefix + ub.base.String()
	sb.WriteString(ub.prefix)
	if ub.key != '/' {
		sb.WriteByte(ub.key)
	}
	if ub.rawLocal != "" {
		sb.WriteString(ub.rawLocal)
		return sb.String()
	}
	for i, p := range ub.path {
		if i > 0 || ub.key != '/' {
			sb.WriteByte('/')
		}
		sb.WriteString(url.PathEscape(p))
	}
	if len(ub.fragment) > 0 {
		sb.WriteByte('#')
		sb.WriteString(ub.fragment)
	}
	for i, q := range ub.query {
		if i == 0 {
			sb.WriteByte('?')
		} else {
			sb.WriteByte('&')
		}
		sb.WriteString(q.key)
		if val := q.val; val != "" {
			sb.WriteByte('=')
			sb.WriteString(url.QueryEscape(val))
		}
	}
	return sb.String()
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

// Package attrs stores attributes of zettel parts.
package attrs

import (
	"slices"
	"strings"

	"zettelstore.de/client.fossil/maps"
	"t73f.de/r/zsc/maps"
)

// Attributes store additional information about some node types.
type Attributes map[string]string

// IsEmpty returns true if there are no attributes.
func (a Attributes) IsEmpty() bool { return len(a) == 0 }

func (a Attributes) Remove(key string) Attributes {
	if a != nil {
		delete(a, key)
	}
	return a
}

// AddClass adds a value to the class attribute.
func (a Attributes) AddClass(class string) Attributes {
// Add a value to an attribute key.
func (a Attributes) Add(key, value string) Attributes {
	if a == nil {
		return map[string]string{"class": class}
		return map[string]string{key: value}
	}
	classes := a.GetClasses()
	for _, cls := range classes {
		if cls == class {
			return a
		}
	}
	values := a.Values(key)
	if !slices.Contains(values, value) {
		values = append(values, value)
		a[key] = strings.Join(values, " ")
	}
	return a
}

	classes = append(classes, class)
	a["class"] = strings.Join(classes, " ")
	return a
}

// Values are the space separated values of an attribute.
func (a Attributes) Values(key string) []string {
	if a != nil {
		if value, ok := a[key]; ok {
			return strings.Fields(value)
		}
	}
// GetClasses returns the class values as a string slice
func (a Attributes) GetClasses() []string {
	if a == nil {
		return nil
	}
	return nil
}
	classes, ok := a["class"]
	if !ok {
		return nil
	}
	return strings.Fields(classes)

// Has the attribute key a value?
func (a Attributes) Has(key, value string) bool {
	return slices.Contains(a.Values(key), value)
}

// HasClass returns true, if attributes contains the given class.
func (a Attributes) HasClass(s string) bool {
// AddClass adds a value to the class attribute.
func (a Attributes) AddClass(class string) Attributes { return a.Add("class", class) }
	if a == nil {
		return false
	}
	classes, found := a["class"]

// GetClasses returns the class values as a string slice
	if !found {
		return false
	}
	return strings.Contains(" "+classes+" ", " "+s+" ")
func (a Attributes) GetClasses() []string { return a.Values("class") }

// HasClass returns true, if attributes contains the given class.
}
func (a Attributes) HasClass(s string) bool { return a.Has("class", s) }

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

package attrs_test

import (
	"testing"

	"zettelstore.de/client.fossil/attrs"
	"t73f.de/r/zsc/attrs"
)

func TestHasDefault(t *testing.T) {
	t.Parallel()
	attr := attrs.Attributes{}
	if attr.HasDefault() {
		t.Error("Should not have default attr")

func TestHasClass(t *testing.T) {
	t.Parallel()
	testcases := []struct {
		classes string
		class   string
		exp     bool
	}{
		{"", "", true},
		{"", "", false},
		{"x", "", false},
		{"x", "x", true},
		{"x", "y", false},
		{"abc def ghi", "abc", true},
		{"abc def ghi", "def", true},
		{"abc def ghi", "ghi", true},
		{"ab de gi", "b", false},

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

// Package client provides a client for accessing the Zettelstore via its API.
package client

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

	"zettelstore.de/client.fossil/api"
	"zettelstore.de/client.fossil/sexp"
	"zettelstore.de/sx.fossil"
	"zettelstore.de/sx.fossil/sxreader"
	"t73f.de/r/sx"
	"t73f.de/r/sx/sxreader"
	"t73f.de/r/zsc/api"
	"t73f.de/r/zsc/sexp"
)

// Client contains all data to execute requests.
type Client struct {
	base      string
	username  string
	password  string
	token     string
	tokenType string
	expires   time.Time
	client    http.Client
}

// Base returns the base part of the URLs that are used to communicate with a Zettelstore.
func (c *Client) Base() string { return c.base }

// NewClient create a new client.
// NewClient creates a new client with a given base URL to a Zettelstore.
func NewClient(u *url.URL) *Client {
	myURL := *u
	myURL.User = nil
	myURL.ForceQuery = false
	myURL.RawQuery = ""
	myURL.Fragment = ""
	myURL.RawFragment = ""
	base := myURL.String()
	if !strings.HasSuffix(base, "/") {
		base += "/"
	}
	c := Client{
		base: base,
		client: http.Client{
			Timeout: 10 * time.Second,
			Transport: &http.Transport{
				DialContext: (&net.Dialer{
					Timeout: 5 * time.Second, // TCP connect timeout
				}).DialContext,
				TLSHandshakeTimeout: 5 * time.Second,
			},
		},
	}
	return &c
}

// AllowRedirect will modify the client to not follow redirect status code when
// using the Zettelstore. The original behaviour can be restored by setting
// allow to false.
func (c *Client) AllowRedirect(allow bool) {
	if allow {
		c.client.CheckRedirect = func(*http.Request, []*http.Request) error {
			return http.ErrUseLastResponse
		}
	} else {
		c.client.CheckRedirect = nil
	}
}

// Error encapsulates the possible client call errors.
//
//   - StatusCode is the HTTP status code, e.g. 200
//   - Message is the HTTP message, e.g. "OK"
//   - Body is the HTTP body returned by a request.
type Error struct {
	StatusCode int
	Message    string
	Body       []byte
}

// Error returns the error as a string.
func (err *Error) Error() string {
	var body string
	if err.Body == nil {
		body = "nil"
	} else if bl := len(err.Body); bl == 0 {
		body = "empty"
	} else {

	return &Error{
		StatusCode: resp.StatusCode,
		Message:    resp.Status[4:],
		Body:       body,
	}
}

// NewURLBuilder creates a new URL builder for the client with the given key.
//
// key is one of the defined lower case letters to specify an endpoint.
// See [Endpoints used by the API] for details.
//
// [Endpoints used by the API]: https://zettelstore.de/manual/h/00001012920000
func (c *Client) newURLBuilder(key byte) *api.URLBuilder {
func (c *Client) NewURLBuilder(key byte) *api.URLBuilder {
	return api.NewURLBuilder(c.base, key)
}
func (*Client) newRequest(ctx context.Context, method string, ub *api.URLBuilder, body io.Reader) (*http.Request, error) {
	return http.NewRequestWithContext(ctx, method, ub.String(), body)
}

func (c *Client) executeRequest(req *http.Request) (*http.Response, error) {
	if c.token != "" {
		req.Header.Add("Authorization", c.tokenType+" "+c.token)
	}
	resp, err := c.client.Do(req)
	if err != nil {
		if resp != nil && resp.Body != nil {
			resp.Body.Close()
			_ = resp.Body.Close()
		}
		return nil, err
	}
	return resp, err
}

func (c *Client) buildAndExecuteRequest(
	ctx context.Context, method string, ub *api.URLBuilder, body io.Reader, h http.Header) (*http.Response, error) {
	ctx context.Context,
	method string,
	ub *api.URLBuilder,
	body io.Reader,
) (*http.Response, error) {
	req, err := c.newRequest(ctx, method, ub, body)
	if err != nil {
		return nil, err
	}
	err = c.updateToken(ctx)
	if err != nil {
		return nil, err
	}
	for key, val := range h {
		req.Header[key] = append(req.Header[key], val...)
	}
	return c.executeRequest(req)
}

// SetAuth sets authentication data.
//
// username and password are the same values that are used to authenticate via the Web-UI.
func (c *Client) SetAuth(username, password string) {
	c.username = username
	c.password = password
	c.token = ""
	c.tokenType = ""
	c.expires = time.Time{}
}

	if err != nil {
		return err
	}
	vals, err := sexp.ParseList(obj, "ssi")
	if err != nil {
		return err
	}
	token := vals[1].(sx.String).String()
	token := vals[1].(sx.String).GetValue()
	if len(token) < 4 {
		return fmt.Errorf("no valid token found: %q", token)
	}
	c.token = token
	c.tokenType = vals[0].(sx.String).String()
	c.tokenType = vals[0].(sx.String).GetValue()
	c.expires = time.Now().Add(time.Duration(vals[2].(sx.Int64)*9/10) * time.Second)
	return nil
}

func (c *Client) updateToken(ctx context.Context) error {
	if c.username == "" {
		return nil
	}
	if time.Now().After(c.expires) {
		return c.Authenticate(ctx)
	}
	return c.RefreshToken(ctx)
}

// Authenticate sets a new token by sending user name and password.
//
// [Client.SetAuth] should be called before.
func (c *Client) Authenticate(ctx context.Context) error {
	authData := url.Values{"username": {c.username}, "password": {c.password}}
	req, err := c.newRequest(ctx, http.MethodPost, c.newURLBuilder('a'), strings.NewReader(authData.Encode()))
	req, err := c.newRequest(ctx, http.MethodPost, c.NewURLBuilder('a'), strings.NewReader(authData.Encode()))
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	return c.executeAuthRequest(req)
}

// RefreshToken updates the access token
//
// [Client.SetAuth] should be called before.
func (c *Client) RefreshToken(ctx context.Context) error {
	req, err := c.newRequest(ctx, http.MethodPut, c.newURLBuilder('a'), nil)
	req, err := c.newRequest(ctx, http.MethodPut, c.NewURLBuilder('a'), nil)
	if err != nil {
		return err
	}
	return c.executeAuthRequest(req)
}

// CreateZettel creates a new zettel and returns its URL.
//
// data contains the zettel metadata and content, as it is stored in a file in a zettel box,
// or as returned by [Client.GetZettel].
// Metadata is separated from zettel content by an empty line.
func (c *Client) CreateZettel(ctx context.Context, data []byte) (api.ZettelID, error) {
	ub := c.newURLBuilder('z')
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPost, ub, bytes.NewBuffer(data), nil)
	ub := c.NewURLBuilder('z')
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPost, ub, bytes.NewBuffer(data))
	if err != nil {
		return api.InvalidZID, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusCreated {
		return api.InvalidZID, statusToError(resp)
	}
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return api.InvalidZID, err
	}
	if zid := api.ZettelID(b); zid.IsValid() {
		return zid, nil
	}
	return api.InvalidZID, err
}

// CreateZettelData creates a new zettel and returns its URL.
//
// data contains the zettel date, encoded as explicit struct.
func (c *Client) CreateZettelData(ctx context.Context, data api.ZettelData) (api.ZettelID, error) {
	var buf bytes.Buffer
	if _, err := sx.Print(&buf, sexp.EncodeZettel(data)); err != nil {
		return api.InvalidZID, err
	}
	ub := c.newURLBuilder('z').AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPost, ub, &buf, nil)
	ub := c.NewURLBuilder('z').AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPost, ub, &buf)
	if err != nil {
		return api.InvalidZID, err
	}
	defer resp.Body.Close()
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	if resp.StatusCode != http.StatusCreated {
		return api.InvalidZID, statusToError(resp)
	}
	if err != nil {
		return api.InvalidZID, err
	}
	return makeZettelID(obj)
}

var bsLF = []byte{'\n'}

// QueryZettel returns a list of all Zettel.
func (c *Client) QueryZettel(ctx context.Context, query string) ([][]byte, error) {
	ub := c.newURLBuilder('z').AppendQuery(query)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return nil, nil
	default:
		return nil, statusToError(resp)
	}
	if err != nil {
		return nil, err
	}
	lines := bytes.Split(data, bsLF)
	if len(lines[len(lines)-1]) == 0 {
		lines = lines[:len(lines)-1]
	}
	return lines, nil
}

// QueryZettelData returns a list of zettel metadata.
func (c *Client) QueryZettelData(ctx context.Context, query string) (string, string, []api.ZidMetaRights, error) {
	ub := c.newURLBuilder('z').AppendKVQuery(api.QueryKeyEncoding, api.EncodingData).AppendQuery(query)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err != nil {
		return "", "", nil, err
	}
	defer resp.Body.Close()
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return "", "", nil, nil
	default:
		return "", "", nil, statusToError(resp)
	}
	if err != nil {
		return "", "", nil, err
	}
	vals, err := sexp.ParseList(obj, "yppp")
	if err != nil {
		return "", "", nil, err
	}
	qVals, err := sexp.ParseList(vals[1], "ys")
	if err != nil {
		return "", "", nil, err
	}
	hVals, err := sexp.ParseList(vals[2], "ys")
	if err != nil {
		return "", "", nil, err
	}
	metaList, err := parseMetaList(vals[3].(*sx.Pair))
	return qVals[1].String(), hVals[1].String(), metaList, err
}

func parseMetaList(metaPair *sx.Pair) ([]api.ZidMetaRights, error) {
	if metaPair == nil {
		return nil, fmt.Errorf("no zettel list")
	}
	if errSym := sexp.CheckSymbol(metaPair.Car(), "list"); errSym != nil {
		return nil, errSym
	}
	var result []api.ZidMetaRights
	for node := metaPair.Cdr(); !sx.IsNil(node); {
		elem, isPair := sx.GetPair(node)
		if !isPair {
			return nil, fmt.Errorf("meta-list not a proper list: %v", metaPair.String())
		}
		node = elem.Cdr()
		vals, err := sexp.ParseList(elem.Car(), "yppp")
		if err != nil {
			return nil, err
		}

		if errSym := sexp.CheckSymbol(vals[0], "zettel"); errSym != nil {
			return nil, errSym
		}

		idVals, err := sexp.ParseList(vals[1], "yi")
		if err != nil {
			return nil, err
		}
		if errSym := sexp.CheckSymbol(idVals[0], "id"); errSym != nil {
			return nil, errSym
		}
		zid, err := makeZettelID(idVals[1])
		if err != nil {
			return nil, err
		}

		meta, err := sexp.ParseMeta(vals[2].(*sx.Pair))
		if err != nil {
			return nil, err
		}

		rights, err := sexp.ParseRights(vals[3])
		if err != nil {
			return nil, err
		}

		result = append(result, api.ZidMetaRights{
			ID:     zid,
			Meta:   meta,
			Rights: rights,
		})
	}
	return result, nil
}
func makeZettelID(obj sx.Object) (api.ZettelID, error) {
	val, isInt64 := obj.(sx.Int64)
	if !isInt64 || val <= 0 {
		return api.InvalidZID, fmt.Errorf("invalid zettel ID: %v", val)
	}
	sVal := strconv.FormatInt(int64(val), 10)
	if len(sVal) < 14 {
		sVal = "00000000000000"[0:14-len(sVal)] + sVal
	}
	zid := api.ZettelID(sVal)
	if !zid.IsValid() {
		return api.InvalidZID, fmt.Errorf("invalid zettel ID: %v", val)
	}
	return zid, nil
}

// QueryAggregate returns a aggregate as a result of a query.
// It is most often used in a query with an action, where the action is either
// a metadata key of type Word, WordSet, or TagSet.
func (c *Client) QueryAggregate(ctx context.Context, query string) (api.Aggregate, error) {
	lines, err := c.QueryZettel(ctx, query)
	if err != nil {
		return nil, err
	}
	if len(lines) == 0 {
		return nil, nil
	}
	agg := make(api.Aggregate, len(lines))
	for _, line := range lines {
		if fields := bytes.Fields(line); len(fields) > 1 {
			key := string(fields[0])
			for _, field := range fields[1:] {
				if zid := api.ZettelID(string(field)); zid.IsValid() {
					agg[key] = append(agg[key], zid)
				}
			}
		}
	}
	return agg, nil
}

// UpdateZettel updates an existing zettel, specified by its zettel identifier.
// GetZettel returns a zettel as a string.
func (c *Client) GetZettel(ctx context.Context, zid api.ZettelID, part string) ([]byte, error) {
	ub := c.newURLBuilder('z').SetZid(zid)
	if part != "" && part != api.PartContent {
		ub.AppendKVQuery(api.QueryKeyPart, part)
	}
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return nil, nil
	default:
		return nil, statusToError(resp)
	}
	return data, err
}

//
// GetZettelData returns a zettel as a struct of its parts.
func (c *Client) GetZettelData(ctx context.Context, zid api.ZettelID) (api.ZettelData, error) {
	ub := c.newURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	ub.AppendKVQuery(api.QueryKeyPart, api.PartZettel)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err == nil {
		defer resp.Body.Close()
		if resp.StatusCode != http.StatusOK {
			return api.ZettelData{}, statusToError(resp)
		}
		rdr := sxreader.MakeReader(resp.Body)
		obj, err2 := rdr.Read()
		if err2 == nil {
			return sexp.ParseZettel(obj)
		}
	}
	return api.ZettelData{}, err
}

// data contains the zettel metadata and content, as it is stored in a file in a zettel box,
// GetParsedZettel return a parsed zettel in a defined encoding.
func (c *Client) GetParsedZettel(ctx context.Context, zid api.ZettelID, enc api.EncodingEnum) ([]byte, error) {
	return c.getZettelString(ctx, zid, enc, true)
}

// or as returned by [Client.GetZettel].
// GetEvaluatedZettel return an evaluated zettel in a defined encoding.
func (c *Client) GetEvaluatedZettel(ctx context.Context, zid api.ZettelID, enc api.EncodingEnum) ([]byte, error) {
	return c.getZettelString(ctx, zid, enc, false)
}

// Metadata is separated from zettel content by an empty line.
func (c *Client) getZettelString(ctx context.Context, zid api.ZettelID, enc api.EncodingEnum, parseOnly bool) ([]byte, error) {
	ub := c.newURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, enc.String())
	ub.AppendKVQuery(api.QueryKeyPart, api.PartContent)
	if parseOnly {
		ub.AppendKVQuery(api.QueryKeyParseOnly, "")
	}
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
	default:
		return nil, statusToError(resp)
	}
	return io.ReadAll(resp.Body)
}

// GetParsedSz returns an parsed zettel as a Sexpr-decoded data structure.
func (c *Client) GetParsedSz(ctx context.Context, zid api.ZettelID, part string, sf sx.SymbolFactory) (sx.Object, error) {
	return c.getSz(ctx, zid, part, true, sf)
}

// GetEvaluatedSz returns an evaluated zettel as a Sexpr-decoded data structure.
func (c *Client) GetEvaluatedSz(ctx context.Context, zid api.ZettelID, part string, sf sx.SymbolFactory) (sx.Object, error) {
	return c.getSz(ctx, zid, part, false, sf)
}

func (c *Client) getSz(ctx context.Context, zid api.ZettelID, part string, parseOnly bool, sf sx.SymbolFactory) (sx.Object, error) {
	ub := c.newURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, api.EncodingSz)
	if part != "" {
		ub.AppendKVQuery(api.QueryKeyPart, part)
	}
	if parseOnly {
		ub.AppendKVQuery(api.QueryKeyParseOnly, "")
	}
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, statusToError(resp)
	}
	return sxreader.MakeReader(bufio.NewReaderSize(resp.Body, 8), sxreader.WithSymbolFactory(sf)).Read()
}

// GetMetaData returns the metadata of a zettel.
func (c *Client) GetMetaData(ctx context.Context, zid api.ZettelID) (api.MetaRights, error) {
	ub := c.newURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	ub.AppendKVQuery(api.QueryKeyPart, api.PartMeta)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil, nil)
	if err != nil {
		return api.MetaRights{}, err
	}
	defer resp.Body.Close()
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	if resp.StatusCode != http.StatusOK {
		return api.MetaRights{}, statusToError(resp)
	}
	if err != nil {
		return api.MetaRights{}, err
	}
	vals, err := sexp.ParseList(obj, "ypp")
	if err != nil {
		return api.MetaRights{}, err
	}
	if errSym := sexp.CheckSymbol(vals[0], "list"); errSym != nil {
		return api.MetaRights{}, err
	}

	meta, err := sexp.ParseMeta(vals[1].(*sx.Pair))
	if err != nil {
		return api.MetaRights{}, err
	}

	rights, err := sexp.ParseRights(vals[2])
	if err != nil {
		return api.MetaRights{}, err
	}

	return api.MetaRights{
		Meta:   meta,
		Rights: rights,
	}, nil
}

// UpdateZettel updates an existing zettel.
func (c *Client) UpdateZettel(ctx context.Context, zid api.ZettelID, data []byte) error {
	ub := c.newURLBuilder('z').SetZid(zid)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPut, ub, bytes.NewBuffer(data), nil)
	ub := c.NewURLBuilder('z').SetZid(zid)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPut, ub, bytes.NewBuffer(data))
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

// UpdateZettelData updates an existing zettel.
// UpdateZettelData updates an existing zettel, specified by its zettel identifier.
func (c *Client) UpdateZettelData(ctx context.Context, zid api.ZettelID, data api.ZettelData) error {
	var buf bytes.Buffer
	if _, err := sx.Print(&buf, sexp.EncodeZettel(data)); err != nil {
		return err
	}
	ub := c.newURLBuilder('z').SetZid(zid).AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPut, ub, &buf, nil)
	ub := c.NewURLBuilder('z').SetZid(zid).AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPut, ub, &buf)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

// RenameZettel renames a zettel.
func (c *Client) RenameZettel(ctx context.Context, oldZid, newZid api.ZettelID) error {
	ub := c.newURLBuilder('z').SetZid(oldZid)
	h := http.Header{
		api.HeaderDestination: {c.newURLBuilder('z').SetZid(newZid).String()},
	}
	resp, err := c.buildAndExecuteRequest(ctx, api.MethodMove, ub, nil, h)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

// DeleteZettel deletes a zettel with the given identifier.
func (c *Client) DeleteZettel(ctx context.Context, zid api.ZettelID) error {
	ub := c.newURLBuilder('z').SetZid(zid)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodDelete, ub, nil, nil)
	ub := c.NewURLBuilder('z').SetZid(zid)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodDelete, ub, nil)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

// ExecuteCommand will execute a given command at the Zettelstore.
//
// See [API commands] for a list of valid commands.
//
// [API commands]: https://zettelstore.de/manual/h/00001012080100
func (c *Client) ExecuteCommand(ctx context.Context, command api.Command) error {
	ub := c.newURLBuilder('x').AppendKVQuery(api.QueryKeyCommand, string(command))
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPost, ub, nil, nil)
	ub := c.NewURLBuilder('x').AppendKVQuery(api.QueryKeyCommand, string(command))
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodPost, ub, nil)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

// GetVersionInfo returns version information..
func (c *Client) GetVersionInfo(ctx context.Context) (VersionInfo, error) {
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, c.newURLBuilder('x'), nil, nil)
	if err != nil {
		return VersionInfo{}, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return VersionInfo{}, statusToError(resp)
	}
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	if err == nil {
		if vals, errVals := sexp.ParseList(obj, "iiiss"); errVals == nil {
			return VersionInfo{
				Major: int(vals[0].(sx.Int64)),
				Minor: int(vals[1].(sx.Int64)),
				Patch: int(vals[2].(sx.Int64)),
				Info:  vals[3].(sx.String).String(),
				Hash:  vals[4].(sx.String).String(),
			}, nil
		}
	}
	return VersionInfo{}, err
}

// VersionInfo contains version information.
type VersionInfo struct {
	Major int
	Minor int
	Patch int
	Info  string
	Hash  string
}

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

package client_test

import (
	"context"
	"flag"
	"net/http"
	"net/url"
	"testing"

	"zettelstore.de/client.fossil/api"
	"t73f.de/r/zsc/api"
	"zettelstore.de/client.fossil/client"
	"zettelstore.de/client.fossil/sz"
	"t73f.de/r/zsc/client"
	"zettelstore.de/sx.fossil"
)

func TestZettelList(t *testing.T) {
	c := getClient()
	_, err := c.QueryZettel(context.Background(), "")
	if err != nil {
		t.Error(err)

		}
		return
	}
}

func TestGetSzZettel(t *testing.T) {
	c := getClient()
	sf := sx.MakeMappedFactory()
	var zetSyms sz.ZettelSymbols
	zetSyms.InitializeZettelSymbols(sf)
	value, err := c.GetEvaluatedSz(context.Background(), api.ZidDefaultHome, api.PartContent, sf)
	value, err := c.GetEvaluatedSz(context.Background(), api.ZidDefaultHome, api.PartContent)
	if err != nil {
		t.Error(err)
		return
	}
	if value.IsNil() {
		t.Error("No data")
	}

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

package client

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"io"
	"net/http"

	"t73f.de/r/sx"
	"t73f.de/r/sx/sxreader"
	"t73f.de/r/zsc/api"
	"t73f.de/r/zsc/sexp"
	"t73f.de/r/zsc/sz"
)

var bsLF = []byte{'\n'}

// QueryZettel returns a list of all Zettel based on the given query.
//
// query is a search expression, as described in [Query the list of all zettel].
//
// The functions returns a slice of bytes slices, where each byte slice contains the
// zettel identifier within its first 14 bytes. The next byte is a space character,
// followed by the title of the zettel.
//
// [Query the list of all zettel]: https://zettelstore.de/manual/h/00001012051400
func (c *Client) QueryZettel(ctx context.Context, query string) ([][]byte, error) {
	ub := c.NewURLBuilder('z').AppendQuery(query)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return nil, nil
	default:
		return nil, statusToError(resp)
	}
	if err != nil {
		return nil, err
	}
	lines := bytes.Split(data, bsLF)
	if len(lines[len(lines)-1]) == 0 {
		lines = lines[:len(lines)-1]
	}
	return lines, nil
}

// QueryZettelData returns a list of zettel metadata.
//
// query is a search expression, as described in [Query the list of all zettel].
//
// The functions returns the normalized query and its human-readable representation as
// its first two result values.
//
// [Query the list of all zettel]: https://zettelstore.de/manual/h/00001012051400
func (c *Client) QueryZettelData(ctx context.Context, query string) (string, string, []api.ZidMetaRights, error) {
	ub := c.NewURLBuilder('z').AppendKVQuery(api.QueryKeyEncoding, api.EncodingData).AppendQuery(query)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return "", "", nil, err
	}
	defer resp.Body.Close()
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return "", "", nil, nil
	default:
		return "", "", nil, statusToError(resp)
	}
	if err != nil {
		return "", "", nil, err
	}
	vals, err := sexp.ParseList(obj, "yppp")
	if err != nil {
		return "", "", nil, err
	}
	qVals, err := sexp.ParseList(vals[1], "ys")
	if err != nil {
		return "", "", nil, err
	}
	hVals, err := sexp.ParseList(vals[2], "ys")
	if err != nil {
		return "", "", nil, err
	}
	metaList, err := parseMetaList(vals[3].(*sx.Pair))
	return sz.GoValue(qVals[1]), sz.GoValue(hVals[1]), metaList, err
}

func parseMetaList(metaPair *sx.Pair) ([]api.ZidMetaRights, error) {
	if metaPair == nil {
		return nil, fmt.Errorf("no zettel list")
	}
	if errSym := sexp.CheckSymbol(metaPair.Car(), "list"); errSym != nil {
		return nil, errSym
	}
	var result []api.ZidMetaRights
	for node := metaPair.Cdr(); !sx.IsNil(node); {
		elem, isPair := sx.GetPair(node)
		if !isPair {
			return nil, fmt.Errorf("meta-list not a proper list: %v", metaPair.String())
		}
		node = elem.Cdr()
		vals, err := sexp.ParseList(elem.Car(), "yppp")
		if err != nil {
			return nil, err
		}

		if errSym := sexp.CheckSymbol(vals[0], "zettel"); errSym != nil {
			return nil, errSym
		}

		idVals, err := sexp.ParseList(vals[1], "yi")
		if err != nil {
			return nil, err
		}
		if errSym := sexp.CheckSymbol(idVals[0], "id"); errSym != nil {
			return nil, errSym
		}
		zid, err := makeZettelID(idVals[1])
		if err != nil {
			return nil, err
		}

		meta, err := sexp.ParseMeta(vals[2].(*sx.Pair))
		if err != nil {
			return nil, err
		}

		rights, err := sexp.ParseRights(vals[3])
		if err != nil {
			return nil, err
		}

		result = append(result, api.ZidMetaRights{
			ID:     zid,
			Meta:   meta,
			Rights: rights,
		})
	}
	return result, nil
}

// QueryAggregate returns a aggregate as a result of a query.
// It is most often used in a query with an action, where the action is either
// a metadata key of type Word or of type TagSet.
//
// query is a search expression, as described in [Query the list of all zettel].
// It must contain an aggregate action.
//
// [Query the list of all zettel]: https://zettelstore.de/manual/h/00001012051400
func (c *Client) QueryAggregate(ctx context.Context, query string) (api.Aggregate, error) {
	lines, err := c.QueryZettel(ctx, query)
	if err != nil {
		return nil, err
	}
	if len(lines) == 0 {
		return nil, nil
	}
	agg := make(api.Aggregate, len(lines))
	for _, line := range lines {
		if fields := bytes.Fields(line); len(fields) > 1 {
			key := string(fields[0])
			for _, field := range fields[1:] {
				if zid := api.ZettelID(string(field)); zid.IsValid() {
					agg[key] = append(agg[key], zid)
				}
			}
		}
	}
	return agg, nil
}

// TagZettel returns the identifier of the tag zettel for a given tag.
//
// This method only works if c.AllowRedirect(true) was called.
func (c *Client) TagZettel(ctx context.Context, tag string) (api.ZettelID, error) {
	return c.fetchTagOrRoleZettel(ctx, api.QueryKeyTag, tag)
}

// RoleZettel returns the identifier of the tag zettel for a given role.
//
// This method only works if c.AllowRedirect(true) was called.
func (c *Client) RoleZettel(ctx context.Context, role string) (api.ZettelID, error) {
	return c.fetchTagOrRoleZettel(ctx, api.QueryKeyRole, role)
}

func (c *Client) fetchTagOrRoleZettel(ctx context.Context, key, val string) (api.ZettelID, error) {
	if c.client.CheckRedirect == nil {
		panic("client does not allow to track redirect")
	}
	ub := c.NewURLBuilder('z').AppendKVQuery(key, val)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return api.InvalidZID, err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return api.InvalidZID, err
	}

	switch resp.StatusCode {
	case http.StatusNotFound:
		return "", nil
	case http.StatusFound:
		zid := api.ZettelID(data)
		if zid.IsValid() {
			return zid, nil
		}
		return api.InvalidZID, nil
	default:
		return api.InvalidZID, statusToError(resp)
	}
}

// GetZettel returns a zettel as a byte slice.
//
// part must be one of "meta", "content", or "zettel".
//
// The format of the byte slice is described in [Layout of a zettel].
//
// [Layout of a zettel]: https://zettelstore.de/manual/h/00001006000000
func (c *Client) GetZettel(ctx context.Context, zid api.ZettelID, part string) ([]byte, error) {
	ub := c.NewURLBuilder('z').SetZid(zid)
	if part != "" && part != api.PartContent {
		ub.AppendKVQuery(api.QueryKeyPart, part)
	}
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return nil, nil
	default:
		return nil, statusToError(resp)
	}
	return data, err
}

// GetZettelData returns a zettel as a struct of its parts.
func (c *Client) GetZettelData(ctx context.Context, zid api.ZettelID) (api.ZettelData, error) {
	ub := c.NewURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	ub.AppendKVQuery(api.QueryKeyPart, api.PartZettel)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err == nil {
		defer resp.Body.Close()
		if resp.StatusCode != http.StatusOK {
			return api.ZettelData{}, statusToError(resp)
		}
		rdr := sxreader.MakeReader(resp.Body)
		obj, err2 := rdr.Read()
		if err2 == nil {
			return sexp.ParseZettel(obj)
		}
	}
	return api.ZettelData{}, err
}

// GetParsedZettel return a parsed zettel in a specified text-based encoding.
//
// A parsed zettel is just read from its box and is not processed any further.
//
// Valid encoding values are given as constants. They are described in more
// detail in [Encodings available via the API].
//
// [Encodings available via the API]: https://zettelstore.de/manual/h/00001012920500
func (c *Client) GetParsedZettel(ctx context.Context, zid api.ZettelID, enc api.EncodingEnum) ([]byte, error) {
	return c.getZettelString(ctx, zid, enc, true)
}

// GetEvaluatedZettel return an evaluated zettel in a specified text-based encoding.
//
// An evaluated zettel was parsed, and any transclusions etc. are resolved.
// This is the zettel representation you typically see on the Web UI.
//
// Valid encoding values are given as constants. They are described in more
// detail in [Encodings available via the API].
//
// [Encodings available via the API]: https://zettelstore.de/manual/h/00001012920500
func (c *Client) GetEvaluatedZettel(ctx context.Context, zid api.ZettelID, enc api.EncodingEnum) ([]byte, error) {
	return c.getZettelString(ctx, zid, enc, false)
}

func (c *Client) getZettelString(ctx context.Context, zid api.ZettelID, enc api.EncodingEnum, parseOnly bool) ([]byte, error) {
	ub := c.NewURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, enc.String())
	ub.AppendKVQuery(api.QueryKeyPart, api.PartContent)
	if parseOnly {
		ub.AppendKVQuery(api.QueryKeyParseOnly, "")
	}
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
	default:
		return nil, statusToError(resp)
	}
	return io.ReadAll(resp.Body)
}

// GetParsedSz returns a part of an parsed zettel as a Sexpr-decoded data structure.
//
// A parsed zettel is just read from its box and is not processed any further.
//
// part must be one of "meta", "content", or "zettel".
//
// Basically, this function returns the sz encoding of a part of a zettel.
func (c *Client) GetParsedSz(ctx context.Context, zid api.ZettelID, part string) (sx.Object, error) {
	return c.getSz(ctx, zid, part, true)
}

// GetEvaluatedSz returns an evaluated zettel as a Sexpr-decoded data structure.
//
// An evaluated zettel was parsed, and any transclusions etc. are resolved.
// This is the zettel representation you typically see on the Web UI.
//
// part must be one of "meta", "content", or "zettel".
//
// Basically, this function returns the sz encoding of a part of a zettel.
func (c *Client) GetEvaluatedSz(ctx context.Context, zid api.ZettelID, part string) (sx.Object, error) {
	return c.getSz(ctx, zid, part, false)
}

func (c *Client) getSz(ctx context.Context, zid api.ZettelID, part string, parseOnly bool) (sx.Object, error) {
	ub := c.NewURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, api.EncodingSz)
	if part != "" {
		ub.AppendKVQuery(api.QueryKeyPart, part)
	}
	if parseOnly {
		ub.AppendKVQuery(api.QueryKeyParseOnly, "")
	}
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, statusToError(resp)
	}
	return sxreader.MakeReader(bufio.NewReaderSize(resp.Body, 8)).Read()
}

// GetMetaData returns the metadata of a zettel.
func (c *Client) GetMetaData(ctx context.Context, zid api.ZettelID) (api.MetaRights, error) {
	ub := c.NewURLBuilder('z').SetZid(zid)
	ub.AppendKVQuery(api.QueryKeyEncoding, api.EncodingData)
	ub.AppendKVQuery(api.QueryKeyPart, api.PartMeta)
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return api.MetaRights{}, err
	}
	defer resp.Body.Close()
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	if resp.StatusCode != http.StatusOK {
		return api.MetaRights{}, statusToError(resp)
	}
	if err != nil {
		return api.MetaRights{}, err
	}
	vals, err := sexp.ParseList(obj, "ypp")
	if err != nil {
		return api.MetaRights{}, err
	}
	if errSym := sexp.CheckSymbol(vals[0], "list"); errSym != nil {
		return api.MetaRights{}, err
	}

	meta, err := sexp.ParseMeta(vals[1].(*sx.Pair))
	if err != nil {
		return api.MetaRights{}, err
	}

	rights, err := sexp.ParseRights(vals[2])
	if err != nil {
		return api.MetaRights{}, err
	}

	return api.MetaRights{
		Meta:   meta,
		Rights: rights,
	}, nil
}

// GetVersionInfo returns version information of the Zettelstore that is used.
func (c *Client) GetVersionInfo(ctx context.Context) (VersionInfo, error) {
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, c.NewURLBuilder('x'), nil)
	if err != nil {
		return VersionInfo{}, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return VersionInfo{}, statusToError(resp)
	}
	rdr := sxreader.MakeReader(resp.Body)
	obj, err := rdr.Read()
	if err == nil {
		if vals, errVals := sexp.ParseList(obj, "iiiss"); errVals == nil {
			return VersionInfo{
				Major: int(vals[0].(sx.Int64)),
				Minor: int(vals[1].(sx.Int64)),
				Patch: int(vals[2].(sx.Int64)),
				Info:  vals[3].(sx.String).GetValue(),
				Hash:  vals[4].(sx.String).GetValue(),
			}, nil
		}
	}
	return VersionInfo{}, err
}

// VersionInfo contains version information of the associated Zettelstore.
//
//   - Major is an integer containing the major software version of Zettelstore.
//     If its value is greater than zero, different major versions are not compatible.
//   - Minor is an integer specifying the minor software version for the given major version.
//     If the major version is greater than zero, minor versions are backward compatible.
//   - Patch is an integer that specifies a change within a minor version.
//     A version that have equal major and minor versions and differ in patch version are
//     always compatible, even if the major version equals zero.
//   - Info contains some optional text, i.e. it may be the empty string. Typically, Info
//     specifies a developer version by containing the string "dev".
//   - Hash contains the value of the source code version stored in the Zettelstore repository.
//     You can use it to reproduce bugs that occured, when source code was changed since
//     its introduction.
type VersionInfo struct {
	Major int
	Minor int
	Patch int
	Info  string
	Hash  string
}

// GetApplicationZid returns the zettel identifier used to configure a client
// application with the given name.
func (c *Client) GetApplicationZid(ctx context.Context, appname string) (api.ZettelID, error) {
	mr, err := c.GetMetaData(ctx, api.ZidAppDirectory)
	if err != nil {
		return api.InvalidZID, err
	}
	key := appname + "-zid"
	val, found := mr.Meta[key]
	if !found {
		return api.InvalidZID, fmt.Errorf("no application registered: %v", appname)
	}
	if zid := api.ZettelID(val); zid.IsValid() {
		return zid, nil
	}
	return api.InvalidZID, fmt.Errorf("invalid identifier for application %v: %v", appname, val)
}

// Get executes a GET request to the given URL and returns the read data.
func (c *Client) Get(ctx context.Context, ub *api.URLBuilder) ([]byte, error) {
	resp, err := c.buildAndExecuteRequest(ctx, http.MethodGet, ub, nil)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	switch resp.StatusCode {
	case http.StatusOK:
	case http.StatusNoContent:
		return nil, nil
	default:
		return nil, statusToError(resp)
	}
	data, err := io.ReadAll(resp.Body)
	return data, err
}

module zettelstore.de/client.fossil
module t73f.de/r/zsc

go 1.20
go 1.23

require zettelstore.de/sx.fossil v0.0.0-20230727172325-adec5a7ba284
require (
	t73f.de/r/sx v0.0.0-20240814083626-4df0ec6454b5
	t73f.de/r/sxwebs v0.0.0-20241031144449-53c3b2ed1a6f
	t73f.de/r/webs v0.0.0-20241031141359-cd4f76a622cd
)

zettelstore.de/sx.fossil v0.0.0-20230727172325-adec5a7ba284 h1:26xwZWEjdyL3wObczc/PKugv0EY6mgSH5NUe5kYFCt4=
zettelstore.de/sx.fossil v0.0.0-20230727172325-adec5a7ba284/go.mod h1:nsWXVrQG8RNKtoXzEMrWXNMdnpfIDU6Hb0pk56KpVKE=
t73f.de/r/sx v0.0.0-20240814083626-4df0ec6454b5 h1:ug4hohM6pK28M8Uo0o3+XvjBure2wfEtuCnHVIdqBZY=
t73f.de/r/sx v0.0.0-20240814083626-4df0ec6454b5/go.mod h1:VRvsWoBErPKvMieDMMk1hsh1tb9sA4ijEQWGw/TbtQ0=
t73f.de/r/sxwebs v0.0.0-20241031144449-53c3b2ed1a6f h1:VJ4S7YWy9tCJuFz5MckqUjjktPaf0kpnTkNBVRVXpo4=
t73f.de/r/sxwebs v0.0.0-20241031144449-53c3b2ed1a6f/go.mod h1:IaM+U+LvYTYeuiIS5cwZW6kcEpdwoKBYVCU7LZr4Sgk=
t73f.de/r/webs v0.0.0-20241031141359-cd4f76a622cd h1:+7cqJonXKDso+uPvsvOPl7BiLkhj8VQT/Has8qC5VIQ=
t73f.de/r/webs v0.0.0-20241031141359-cd4f76a622cd/go.mod h1:NSoOON8be62MfQZzlCApK27Jt2zhIa6Vrmo9RJ4tOnQ=

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

package input

import (
	"html"
	"unicode"
)

// ScanEntity scans either a named or a numbered entity and returns it as a string.
//
// For numbered entities (like { or ģ) html.UnescapeString returns
// sometimes other values as expected, if the number is not well-formed. This
// may happen because of some strange HTML parsing rules. But these do not
// apply to Zettelmarkup. Therefore, I parse the number here in the code.
func (inp *Input) ScanEntity() (res string, success bool) {
	if inp.Ch != '&' {
		return "", false
	}
	pos := inp.Pos
	inp.Next()
	if inp.Ch == '#' {
		inp.Next()
		if inp.Ch == 'x' || inp.Ch == 'X' {
			return inp.scanEntityBase16()
		}
		return inp.scanEntityBase10()
	}
	return inp.scanEntityNamed(pos)
}

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

func (inp *Input) scanEntityBase10() (string, bool) {
	// Base 10 code
	if inp.Ch == ';' {
		return "", false
	}
	code := 0
	for {
		switch ch := inp.Ch; ch {
		case ';':
			inp.Next()
			if r := rune(code); isValidEntity(r) {
				return string(r), true
			}
			return "", false
		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
			code = 10*code + int(ch-'0')
		default:
			return "", false
		}
		if code > unicode.MaxRune {
			return "", false
		}
		inp.Next()
	}
}
func (inp *Input) scanEntityNamed(pos int) (string, bool) {
	for {
		switch inp.Ch {
		case EOS, '\n', '\r', '&':
			return "", false
		case ';':
			inp.Next()
			es := string(inp.Src[pos:inp.Pos])
			ues := html.UnescapeString(es)
			if es == ues {
				return "", false
			}
			return ues, true
		default:
			inp.Next()
		}
	}
}

// isValidEntity checks if the given code is valid for an entity.
//
// According to https://html.spec.whatwg.org/multipage/syntax.html#character-references
// ""The numeric character reference forms described above are allowed to reference any code point
// excluding U+000D CR, noncharacters, and controls other than ASCII whitespace.""
func isValidEntity(r rune) bool {
	// No C0 control and no "code point in the range U+007F DELETE to U+009F APPLICATION PROGRAM COMMAND, inclusive."
	if r < ' ' || ('\u007f' <= r && r <= '\u009f') {
		return false
	}

	// If below any noncharacter code point, return true
	//
	// See: https://infra.spec.whatwg.org/#noncharacter
	if r < '\ufdd0' {
		return true
	}

	// First range of noncharacter code points: "(...) in the range U+FDD0 to U+FDEF, inclusive"
	if r <= '\ufdef' {
		return false
	}

	// Other noncharacter code points:
	switch r {
	case '\uFFFE', '\uFFFF',
		'\U0001FFFE', '\U0001FFFF',
		'\U0002FFFE', '\U0002FFFF',
		'\U0003FFFE', '\U0003FFFF',
		'\U0004FFFE', '\U0004FFFF',
		'\U0005FFFE', '\U0005FFFF',
		'\U0006FFFE', '\U0006FFFF',
		'\U0007FFFE', '\U0007FFFF',
		'\U0008FFFE', '\U0008FFFF',
		'\U0009FFFE', '\U0009FFFF',
		'\U000AFFFE', '\U000AFFFF',
		'\U000BFFFE', '\U000BFFFF',
		'\U000CFFFE', '\U000CFFFF',
		'\U000DFFFE', '\U000DFFFF',
		'\U000EFFFE', '\U000EFFFF',
		'\U000FFFFE', '\U000FFFFF',
		'\U0010FFFE', '\U0010FFFF':
		return false
	}
	return true
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

package input_test

import (
	"testing"

	"t73f.de/r/zsc/input"
)

func TestScanEntity(t *testing.T) {
	t.Parallel()
	var testcases = []struct {
		text string
		exp  string
	}{
		{"", ""},
		{"a", ""},
		{"&", "&"},
		{"!", "!"},
		{"3", "3"},
		{""", "\""},
	}
	for id, tc := range testcases {
		inp := input.NewInput([]byte(tc.text))
		got, ok := inp.ScanEntity()
		if !ok {
			if tc.exp != "" {
				t.Errorf("ID=%d, text=%q: expected error, but got %q", id, tc.text, got)
			}
			if inp.Pos != 0 {
				t.Errorf("ID=%d, text=%q: input position advances to %d", id, tc.text, inp.Pos)
			}
			continue
		}
		if tc.exp != got {
			t.Errorf("ID=%d, text=%q: expected %q, but got %q", id, tc.text, tc.exp, got)
		}
	}
}

func TestScanIllegalEntity(t *testing.T) {
	t.Parallel()
	testcases := []string{"", "a", "& Input →", "	", ""}
	for i, tc := range testcases {
		inp := input.NewInput([]byte(tc))
		got, ok := inp.ScanEntity()
		if ok {
			t.Errorf("%d: scanning %q was unexpected successful, got %q", i, tc, got)
			continue
		}
	}
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

// Package input provides an abstraction for data to be read.
package input

import "unicode/utf8"

// Input is an abstract input source
type Input struct {
	// Read-only, will never change
	Src []byte // The source string

	// Read-only, will change
	Ch      rune // current character
	Pos     int  // character position in src
	readPos int  // reading position (position after current character)
}

// NewInput creates a new input source.
func NewInput(src []byte) *Input {
	inp := &Input{Src: src}
	inp.Next()
	return inp
}

// EOS = End of source
const EOS = rune(-1)

// Next reads the next rune into inp.Ch and returns it too.
func (inp *Input) Next() rune {
	if inp.readPos >= len(inp.Src) {
		inp.Pos = len(inp.Src)
		inp.Ch = EOS
		return EOS
	}
	inp.Pos = inp.readPos
	r, w := rune(inp.Src[inp.readPos]), 1
	if r >= utf8.RuneSelf {
		r, w = utf8.DecodeRune(inp.Src[inp.readPos:])
	}
	inp.readPos += w
	inp.Ch = r
	return r
}

// Peek returns the rune following the most recently read rune without
// advancing. If end-of-source was already found peek returns EOS.
func (inp *Input) Peek() rune {
	return inp.PeekN(0)
}

// PeekN returns the n-th rune after the most recently read rune without
// advancing. If end-of-source was already found peek returns EOS.
func (inp *Input) PeekN(n int) rune {
	pos := inp.readPos + n
	if pos < len(inp.Src) {
		r := rune(inp.Src[pos])
		if r >= utf8.RuneSelf {
			r, _ = utf8.DecodeRune(inp.Src[pos:])
		}
		if r == '\t' {
			return ' '
		}
		return r
	}
	return EOS
}

// Accept checks if the given string is a prefix of the text to be parsed.
// If successful, advance position and current character.
// String must only contain bytes < 128.
// If not successful, everything remains as it is.
func (inp *Input) Accept(s string) bool {
	pos := inp.Pos
	remaining := len(inp.Src) - pos
	if s == "" || len(s) > remaining {
		return false
	}
	// According to internal documentation of bytes.Equal, the string() will not allocate any memory.
	if readPos := pos + len(s); s == string(inp.Src[pos:readPos]) {
		inp.readPos = readPos
		inp.Next()
		return true
	}
	return false
}

// IsEOLEOS returns true if char is either EOS or EOL.
func IsEOLEOS(ch rune) bool { return ch == EOS || ch == '\n' || ch == '\r' }

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

// SetPos allows to reset the read position.
func (inp *Input) SetPos(pos int) {
	if inp.Pos != pos {
		inp.readPos = pos
		inp.Next()
	}
}

// SkipSpace reads while the current character is not a space character.
func (inp *Input) SkipSpace() {
	for ch := inp.Ch; IsSpace(ch); {
		ch = inp.Next()
	}
}

// SkipToEOL reads until the next end-of-line.
func (inp *Input) SkipToEOL() {
	for {
		switch inp.Ch {
		case EOS, '\n', '\r':
			return
		}
		inp.Next()
	}
}

// ScanLineContent reads the reaining input stream and interprets it as lines of text.
func (inp *Input) ScanLineContent() []byte {
	result := make([]byte, 0, len(inp.Src)-inp.Pos+1)
	for {
		inp.EatEOL()
		posL := inp.Pos
		if inp.Ch == EOS {
			return result
		}
		inp.SkipToEOL()
		if len(result) > 0 {
			result = append(result, '\n')
		}
		result = append(result, inp.Src[posL:inp.Pos]...)
	}
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

// Package input_test provides some unit-tests for reading data.
package input_test

import (
	"testing"

	"t73f.de/r/zsc/input"
)

func TestEatEOL(t *testing.T) {
	t.Parallel()
	inp := input.NewInput(nil)
	inp.EatEOL()
	if inp.Ch != input.EOS {
		t.Errorf("No EOS found: %q", inp.Ch)
	}
	if inp.Pos != 0 {
		t.Errorf("Pos != 0: %d", inp.Pos)
	}

	inp = input.NewInput([]byte("ABC"))
	if inp.Ch != 'A' {
		t.Errorf("First ch != 'A', got %q", inp.Ch)
	}
	inp.EatEOL()
	if inp.Ch != 'A' {
		t.Errorf("First ch != 'A', got %q", inp.Ch)
	}
}

func TestAccept(t *testing.T) {
	t.Parallel()
	testcases := []struct {
		accept string
		src    string
		acc    bool
		exp    rune
	}{
		{"", "", false, input.EOS},
		{"AB", "abc", false, 'a'},
		{"AB", "ABC", true, 'C'},
		{"AB", "AB", true, input.EOS},
		{"AB", "A", false, 'A'},
	}
	for i, tc := range testcases {
		inp := input.NewInput([]byte(tc.src))
		acc := inp.Accept(tc.accept)
		if acc != tc.acc {
			t.Errorf("%d: %q.Accept(%q) == %v, but got %v", i, tc.src, tc.accept, tc.acc, acc)
		}
		if got := inp.Ch; tc.exp != got {
			t.Errorf("%d: %q.Accept(%q) should result in run %v, but got %v", i, tc.src, tc.accept, tc.exp, got)
		}
	}
}

//-----------------------------------------------------------------------------
// Copyright (c) 2020-present Detlef Stern
//
// This file is part of zettelstore-client.
//
// Zettelstore client is licensed under the latest version of the EUPL
// (European Union Public License). Please see file LICENSE.txt for your rights
// and obligations under this license.
//
// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2020-present Detlef Stern
//-----------------------------------------------------------------------------

package input

import "unicode"

// IsSpace returns true if rune is a whitespace.
func IsSpace(ch rune) bool {
	switch ch {
	case ' ', '\t':
		return true
	case '\n', '\r', EOS:
		return false
	}
	return unicode.IsSpace(ch)
}

// IsSpace returns true if current character is a whitespace.
func (inp *Input) IsSpace() bool { return IsSpace(inp.Ch) }

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

// Package maps provides utility functions to work with maps.
package maps

import "sort"

// Keys returns the sorted list of string keys of the given map.
func Keys[T any](m map[string]T) []string {
	if len(m) == 0 {
		return nil
	}
	result := make([]string, 0, len(m))
	for k := range m {
		result = append(result, k)

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

package maps_test

import (
	"testing"

	"zettelstore.de/client.fossil/maps"
	"t73f.de/r/zsc/maps"
)

func isSorted(seq []string) bool {
	for i := 1; i < len(seq); i++ {
		if seq[i] < seq[i-1] {
			return false
		}

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

// Package sexp contains helper function to work with s-expression in an alien
// environment.
package sexp

import (
	"errors"
	"fmt"
	"sort"

	"zettelstore.de/client.fossil/api"
	"zettelstore.de/sx.fossil"
	"t73f.de/r/sx"
	"t73f.de/r/zsc/api"
)

// EncodeZettel transforms zettel data into a sx object.
func EncodeZettel(zettel api.ZettelData) sx.Object {
	sf := sx.MakeMappedFactory()
	return sx.MakeList(
		sf.MustMake("zettel"),
		meta2sz(zettel.Meta, sf),
		sx.MakeList(sf.MustMake("rights"), sx.Int64(int64(zettel.Rights))),
		sx.MakeList(sf.MustMake("encoding"), sx.MakeString(zettel.Encoding)),
		sx.MakeList(sf.MustMake("content"), sx.MakeString(zettel.Content)),
		sx.MakeSymbol("zettel"),
		meta2sz(zettel.Meta),
		sx.MakeList(sx.MakeSymbol("rights"), sx.Int64(int64(zettel.Rights))),
		sx.MakeList(sx.MakeSymbol("encoding"), sx.MakeString(zettel.Encoding)),
		sx.MakeList(sx.MakeSymbol("content"), sx.MakeString(zettel.Content)),
	)
}

// ParseZettel parses an object to contain all needed data for a zettel.
func ParseZettel(obj sx.Object) (api.ZettelData, error) {
	vals, err := ParseList(obj, "ypppp")
	if err != nil {
		return api.ZettelData{}, err
	}
	if errSym := CheckSymbol(vals[0], "zettel"); errSym != nil {
		return api.ZettelData{}, errSym

	if errSym := CheckSymbol(contentVals[0], "content"); errSym != nil {
		return api.ZettelData{}, errSym
	}

	return api.ZettelData{
		Meta:     meta,
		Rights:   rights,
		Encoding: encVals[1].(sx.String).String(),
		Content:  contentVals[1].(sx.String).String(),
		Encoding: encVals[1].(sx.String).GetValue(),
		Content:  contentVals[1].(sx.String).GetValue(),
	}, nil
}

// EncodeMetaRights translates metadata/rights into a sx object.
func EncodeMetaRights(mr api.MetaRights) *sx.Pair {
	sf := sx.MakeMappedFactory()
	return sx.MakeList(
		sf.MustMake("list"),
		meta2sz(mr.Meta, sf),
		sx.MakeList(sf.MustMake("rights"), sx.Int64(int64(mr.Rights))),
		sx.SymbolList,
		meta2sz(mr.Meta),
		sx.MakeList(sx.MakeSymbol("rights"), sx.Int64(int64(mr.Rights))),
	)
}

func meta2sz(m api.ZettelMeta, sf sx.SymbolFactory) sx.Object {
	result := sx.Nil().Cons(sf.MustMake("meta"))
	curr := result
func meta2sz(m api.ZettelMeta) sx.Object {
	var result sx.ListBuilder
	result.Add(sx.MakeSymbol("meta"))
	keys := make([]string, 0, len(m))
	for k := range m {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		val := sx.MakeList(sf.MustMake(k), sx.MakeString(m[k]))
		curr = curr.AppendBang(val)
		val := sx.MakeList(sx.MakeSymbol(k), sx.MakeString(m[k]))
		result.Add(val)
	}
	return result
	return result.List()
}

// ParseMeta translates the given list to metadata.
func ParseMeta(pair *sx.Pair) (api.ZettelMeta, error) {
	if err := CheckSymbol(pair.Car(), "meta"); err != nil {
		return nil, err
	}
	res := api.ZettelMeta{}
	for node := pair.Tail(); node != nil; node = node.Tail() {
		mVals, err := ParseList(node.Car(), "ys")
		if err != nil {
			return nil, err
		}
		res[mVals[0].(*sx.Symbol).Name()] = mVals[1].(sx.String).String()
		res[(mVals[0].(*sx.Symbol)).GetValue()] = mVals[1].(sx.String).GetValue()
	}
	return res, nil
}

// ParseRights returns the rights values of the given object.
func ParseRights(obj sx.Object) (api.ZettelRights, error) {
	rVals, err := ParseList(obj, "yi")

	if i64 < 0 && i64 >= int64(api.ZettelMaxRight) {
		return api.ZettelMaxRight, fmt.Errorf("invalid zettel right value: %v", i64)
	}
	return api.ZettelRights(i64), nil
}

// ParseList parses the given object as a proper list, based on a type specification.
func ParseList(obj sx.Object, spec string) ([]sx.Object, error) {
func ParseList(obj sx.Object, spec string) (sx.Vector, error) {
	pair, isPair := sx.GetPair(obj)
	if !isPair {
		return nil, fmt.Errorf("not a list: %T/%v", obj, obj)
	}
	if pair == nil {
		if spec == "" {
			return nil, nil
		}
		return nil, ErrElementsMissing
	}

	result := make([]sx.Object, 0, len(spec))
	result := make(sx.Vector, 0, len(spec))
	node, i := pair, 0
	for ; node != nil; i++ {
		if i >= len(spec) {
			return nil, ErrNoSpec
		}
		var val sx.Object
		var ok bool
		car := node.Car()
		switch spec[i] {
		case 'b':
			val, ok = sx.GetBoolean(car)
			val, ok = sx.MakeBoolean(!sx.IsNil(car)), true
		case 'i':
			val, ok = car.(sx.Int64)
		case 'o':
			val, ok = car, true
		case 'p':
			val, ok = sx.GetPair(car)
		case 's':

	}
	if i < len(spec) {
		return nil, ErrElementsMissing
	}
	return result, nil
}

// ErrElementsMissing is returned,
// if ParseList is called with a list smaller than the number of type specifications.
var ErrElementsMissing = errors.New("spec contains more data")

// ErrNoSpec is returned,
// if ParseList if called with a list greater than the number of type specifications.
var ErrNoSpec = errors.New("no spec for elements")

// CheckSymbol ensures that the given object is a symbol with the given name.
func CheckSymbol(obj sx.Object, name string) error {
	sym, isSymbol := sx.GetSymbol(obj)
	if !isSymbol {
		return fmt.Errorf("object %v/%T is not a symbol", obj, obj)
	}
	if got := sym.Name(); got != name {
	if got := sym.GetValue(); got != name {
		return fmt.Errorf("symbol %q expected, but got: %q", name, got)
	}
	return nil
}

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

package sexp_test

import (
	"testing"

	"zettelstore.de/client.fossil/sexp"
	"zettelstore.de/sx.fossil"
	"t73f.de/r/sx"
	"t73f.de/r/zsc/sexp"
)

func TestParseObject(t *testing.T) {
	if elems, err := sexp.ParseList(sx.MakeString("a"), "s"); err == nil {
		t.Error("expected an error, but got: ", elems)
	}
	if elems, err := sexp.ParseList(sx.Nil(), ""); err != nil {

	if elems, err := sexp.ParseList(sx.MakeList(sx.MakeString("a")), "ss"); err == nil {
		t.Error("expected error, but got: ", elems)
	}
	if elems, err := sexp.ParseList(sx.MakeList(sx.MakeString("a")), ""); err == nil {
		t.Error("expected error, but got: ", elems)
	}
	if elems, err := sexp.ParseList(sx.MakeList(sx.MakeString("a")), "b"); err == nil {
		t.Error("expected error, but got: ", elems)
	if _, err := sexp.ParseList(sx.MakeList(sx.MakeString("a")), "b"); err != nil {
		t.Error("expected [1], but got error: ", err)
	}
	if elems, err := sexp.ParseList(sx.Cons(sx.Nil(), sx.MakeString("a")), "ps"); err == nil {
		t.Error("expected error, but got: ", elems)
	}

	if elems, err := sexp.ParseList(sx.MakeList(sx.MakeString("a")), "s"); err != nil {
		t.Error(err)

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

package shtml

import "t73f.de/r/sx"

// Symbols for HTML header tags
var (
	SymBody   = sx.MakeSymbol("body")
	SymHead   = sx.MakeSymbol("head")
	SymHTML   = sx.MakeSymbol("html")
	SymMeta   = sx.MakeSymbol("meta")
	SymScript = sx.MakeSymbol("script")
	SymTitle  = sx.MakeSymbol("title")
)

// Symbols for HTML body tags
var (
	SymA          = sx.MakeSymbol("a")
	SymASIDE      = sx.MakeSymbol("aside")
	symBLOCKQUOTE = sx.MakeSymbol("blockquote")
	symBR         = sx.MakeSymbol("br")
	symCITE       = sx.MakeSymbol("cite")
	symCODE       = sx.MakeSymbol("code")
	symDD         = sx.MakeSymbol("dd")
	symDEL        = sx.MakeSymbol("del")
	SymDIV        = sx.MakeSymbol("div")
	symDL         = sx.MakeSymbol("dl")
	symDT         = sx.MakeSymbol("dt")
	symEM         = sx.MakeSymbol("em")
	SymEMBED      = sx.MakeSymbol("embed")
	SymFIGURE     = sx.MakeSymbol("figure")
	SymH1         = sx.MakeSymbol("h1")
	SymH2         = sx.MakeSymbol("h2")
	SymHR         = sx.MakeSymbol("hr")
	SymIMG        = sx.MakeSymbol("img")
	symINS        = sx.MakeSymbol("ins")
	symKBD        = sx.MakeSymbol("kbd")
	SymLI         = sx.MakeSymbol("li")
	symMARK       = sx.MakeSymbol("mark")
	SymOL         = sx.MakeSymbol("ol")
	SymP          = sx.MakeSymbol("p")
	symPRE        = sx.MakeSymbol("pre")
	symSAMP       = sx.MakeSymbol("samp")
	SymSPAN       = sx.MakeSymbol("span")
	SymSTRONG     = sx.MakeSymbol("strong")
	symSUB        = sx.MakeSymbol("sub")
	symSUP        = sx.MakeSymbol("sup")
	symTABLE      = sx.MakeSymbol("table")
	symTBODY      = sx.MakeSymbol("tbody")
	symTHEAD      = sx.MakeSymbol("thead")
	symTD         = sx.MakeSymbol("td")
	symTH         = sx.MakeSymbol("th")
	symTR         = sx.MakeSymbol("tr")
	SymUL         = sx.MakeSymbol("ul")
)

// Symbols for HTML attribute keys
var (
	symAttrAlt    = sx.MakeSymbol("alt")
	SymAttrClass  = sx.MakeSymbol("class")
	SymAttrHref   = sx.MakeSymbol("href")
	SymAttrID     = sx.MakeSymbol("id")
	SymAttrLang   = sx.MakeSymbol("lang")
	SymAttrOpen   = sx.MakeSymbol("open")
	SymAttrRel    = sx.MakeSymbol("rel")
	SymAttrRole   = sx.MakeSymbol("role")
	SymAttrSrc    = sx.MakeSymbol("src")
	SymAttrTarget = sx.MakeSymbol("target")
	SymAttrTitle  = sx.MakeSymbol("title")
	SymAttrType   = sx.MakeSymbol("type")
	SymAttrValue  = sx.MakeSymbol("value")
)

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

package shtml

import (
	"strings"

	"t73f.de/r/zsc/api"
)

// LangStack is a stack to store the nesting of "lang" attribute values.
// It is used to generate typographically correct quotes.
type LangStack []string

// NewLangStack creates a new language stack.
func NewLangStack(lang string) LangStack {
	ls := make([]string, 1, 16)
	ls[0] = lang
	return ls
}

// Reset restores the language stack to its initial value.
func (ls *LangStack) Reset() {
	*ls = (*ls)[0:1]
}

// Push adds a new language value.
func (ls *LangStack) Push(lang string) {
	*ls = append(*ls, lang)
}

// Pop removes the topmost language value.
func (ls *LangStack) Pop() {
	*ls = (*ls)[0 : len(*ls)-1]
}

// Top returns the topmost language value.
func (ls *LangStack) Top() string {
	return (*ls)[len(*ls)-1]
}

// Dup duplicates the topmost language value.
func (ls *LangStack) Dup() {
	*ls = append(*ls, (*ls)[len(*ls)-1])
}

// QuoteInfo contains language specific data about quotes.
type QuoteInfo struct {
	primLeft, primRight string
	secLeft, secRight   string
	nbsp                bool
}

// GetPrimary returns the primary left and right quote entity.
func (qi *QuoteInfo) GetPrimary() (string, string) {
	return qi.primLeft, qi.primRight
}

// GetSecondary returns the secondary left and right quote entity.
func (qi *QuoteInfo) GetSecondary() (string, string) {
	return qi.secLeft, qi.secRight
}

// GetQuotes returns quotes based on a nesting level.
func (qi *QuoteInfo) GetQuotes(level uint) (string, string) {
	if level%2 == 0 {
		return qi.GetPrimary()
	}
	return qi.GetSecondary()
}

// GetNBSp returns true, if there must be a non-breaking space between the
// quote entities and the quoted text.
func (qi *QuoteInfo) GetNBSp() bool { return qi.nbsp }

var langQuotes = map[string]*QuoteInfo{
	"":              {""", """, """, """, false},
	api.ValueLangEN: {"“", "”", "‘", "’", false},
	"de":            {"„", "“", "‚", "‘", false},
	"fr":            {"«", "»", "‹", "›", true},
}

// GetQuoteInfo returns language specific data about quotes.
func GetQuoteInfo(lang string) *QuoteInfo {
	langFields := strings.FieldsFunc(lang, func(r rune) bool { return r == '-' || r == '_' })
	for len(langFields) > 0 {
		langSup := strings.Join(langFields, "-")
		quotes, ok := langQuotes[langSup]
		if ok {
			return quotes
		}
		langFields = langFields[0 : len(langFields)-1]
	}
	return langQuotes[""]
}

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

// Package shtml transforms a s-expr encoded zettel AST into a s-expr representation of HTML.
package shtml

import (
	"fmt"
	"net/url"
	"strconv"
	"strings"

	"zettelstore.de/client.fossil/api"
	"t73f.de/r/sx"
	"zettelstore.de/client.fossil/attrs"
	"zettelstore.de/client.fossil/sz"
	"zettelstore.de/client.fossil/text"
	"zettelstore.de/sx.fossil"
	"t73f.de/r/sxwebs/sxhtml"
	"t73f.de/r/zsc/api"
	"t73f.de/r/zsc/attrs"
	"zettelstore.de/sx.fossil/sxbuiltins/quote"
	"zettelstore.de/sx.fossil/sxeval"
	"zettelstore.de/sx.fossil/sxhtml"
	"t73f.de/r/zsc/sz"
	"t73f.de/r/zsc/text"
)

// Transformer will transform a s-expression that encodes the zettel AST into an s-expression
// Evaluator will transform a s-expression that encodes the zettel AST into an s-expression
// that represents HTML.
type Transformer struct {
type Evaluator struct {
	sf            sx.SymbolFactory
	rebinder      RebindProc
	headingOffset int64
	unique        string
	endnotes      []endnoteInfo
	noLinks       bool // true iff output must not include links
	symAttr       *sx.Symbol
	symClass      *sx.Symbol
	symMeta       *sx.Symbol
	symA          *sx.Symbol
	symSpan       *sx.Symbol
}

type endnoteInfo struct {

	fns     map[string]EvalFn
	minArgs map[string]int
	noteAST *sx.Pair // Endnote as AST
	noteHx  *sx.Pair // Endnote as SxHTML
	attrs   *sx.Pair // attrs a-list
}

// NewTransformer creates a new transformer object.
func NewTransformer(headingOffset int, sf sx.SymbolFactory) *Transformer {
	if sf == nil {
// NewEvaluator creates a new Evaluator object.
func NewEvaluator(headingOffset int) *Evaluator {
	ev := &Evaluator{
		sf = sx.MakeMappedFactory()
	}
	return &Transformer{
		sf:            sf,
		rebinder:      nil,
		headingOffset: int64(headingOffset),
		symAttr:       sf.MustMake(sxhtml.NameSymAttr),
		symClass:      sf.MustMake("class"),
		symMeta:       sf.MustMake("meta"),
		symA:          sf.MustMake("a"),
		symSpan:       sf.MustMake("span"),
	}
}


		fns:     make(map[string]EvalFn, 128),
		minArgs: make(map[string]int, 128),
	}
	ev.bindMetadata()
	ev.bindBlocks()
	ev.bindInlines()
	return ev
}
// SymbolFactory returns the symbol factory to create HTML symbols.
func (tr *Transformer) SymbolFactory() sx.SymbolFactory { return tr.sf }

// SetUnique sets a prefix to make several HTML ids unique.
func (tr *Transformer) SetUnique(s string) { tr.unique = s }
func (ev *Evaluator) SetUnique(s string) { ev.unique = s }

// IsValidName returns true, if name is a valid symbol name.
func (tr *Transformer) IsValidName(s string) bool { return tr.sf.IsValidName(s) }
func isValidName(s string) bool { return s != "" }

// Make a new HTML symbol.
func (tr *Transformer) Make(s string) *sx.Symbol { return tr.sf.MustMake(s) }

// RebindProc is a procedure which is called every time before a tranformation takes place.
type RebindProc func(*TransformEnv)

// SetRebinder sets the rebinder procedure.
func (tr *Transformer) SetRebinder(rb RebindProc) { tr.rebinder = rb }

// TransformAttrbute transforms the given attributes into a HTML s-expression.
func (tr *Transformer) TransformAttrbute(a attrs.Attributes) *sx.Pair {
// EvaluateAttrbute transforms the given attributes into a HTML s-expression.
func EvaluateAttrbute(a attrs.Attributes) *sx.Pair {
	if len(a) == 0 {
		return nil
	}
	plist := sx.Nil()
	keys := a.Keys()
	for i := len(keys) - 1; i >= 0; i-- {
		key := keys[i]
		if key != attrs.DefaultAttribute && tr.IsValidName(key) {
			plist = plist.Cons(sx.Cons(tr.Make(key), sx.MakeString(a[key])))
		if key != attrs.DefaultAttribute && isValidName(key) {
			plist = plist.Cons(sx.Cons(sx.MakeSymbol(key), sx.MakeString(a[key])))
		}
	}
	if plist == nil {
		return nil
	}
	return plist.Cons(tr.symAttr)
	return plist.Cons(sxhtml.SymAttr)
}

// TransformMeta creates a HTML meta s-expression
func (tr *Transformer) TransformMeta(a attrs.Attributes) *sx.Pair {
	return sx.Nil().Cons(tr.TransformAttrbute(a)).Cons(tr.symMeta)
}

// Transform an AST s-expression into a list of HTML s-expressions.
// Evaluate a metadata s-expression into a list of HTML s-expressions.
func (ev *Evaluator) Evaluate(lst *sx.Pair, env *Environment) (*sx.Pair, error) {
	result := ev.Eval(lst, env)
	if err := env.err; err != nil {
		return nil, err
	}
	pair, isPair := sx.GetPair(result)
	if !isPair {
		return nil, fmt.Errorf("evaluation does not result in a pair, but %T/%v", result, result)
	}

	for i := 0; i < len(env.endnotes); i++ {
		// May extend tr.endnotes -> do not use for i := range len(...)!!!

		if env.endnotes[i].noteHx != nil {
			continue
		}

func (tr *Transformer) Transform(lst *sx.Pair) (*sx.Pair, error) {
	astSF := sx.FindSymbolFactory(lst)
	if astSF != nil {
		noteHx, _ := ev.EvaluateList(env.endnotes[i].noteAST, env)
		env.endnotes[i].noteHx = noteHx
		if astSF == tr.sf {
			panic("Invalid AST SymbolFactory")
		}
	}
	} else {
		astSF = sx.MakeMappedFactory()
	}

	astEnv := sx.MakeRootEnvironment()
	engine := sxeval.MakeEngine(astSF, astEnv)
	quote.InstallQuoteSyntax(astEnv, astSF.MustMake(sz.NameSymQuote))
	te := TransformEnv{
		tr:      tr,
		astSF:   astSF,
		astEnv:  astEnv,
		err:     nil,
	return pair, nil
		textEnc: text.NewEncoder(astSF),
	}
}
	te.initialize()
	if rb := tr.rebinder; rb != nil {
		rb(&te)
	}


// EvaluateList will evaluate all list elements separately and returns them as a sx.Pair list
func (ev *Evaluator) EvaluateList(lst sx.Vector, env *Environment) (*sx.Pair, error) {
	var result sx.ListBuilder
	for _, elem := range lst {
		p := ev.Eval(elem, env)
		result.Add(p)
	}
	val, err := engine.Eval(te.astEnv, lst)
	if err != nil {
	if err := env.err; err != nil {
		return nil, err
	}
	res, isPair := sx.GetPair(val)
	if !isPair {
		panic("Result is not a list")
	}
	for i := 0; i < len(tr.endnotes); i++ {
		// May extend tr.endnotes
		val, err = engine.Eval(te.astEnv, tr.endnotes[i].noteAST)
		if err != nil {
			return res, err
	return result.List(), nil
		}
		en, ok := sx.GetPair(val)
		if !ok {
			panic("Endnote is not a list")
		}
		tr.endnotes[i].noteHx = en
	}
	return res, err

}

// Endnotes returns a SHTML object with all collected endnotes.
func (tr *Transformer) Endnotes() *sx.Pair {
	if len(tr.endnotes) == 0 {
func Endnotes(env *Environment) *sx.Pair {
	if env.err != nil || len(env.endnotes) == 0 {
		return nil
	}
	result := sx.Nil().Cons(tr.Make("ol"))
	currResult := result.AppendBang(sx.Nil().Cons(sx.Cons(tr.symClass, sx.MakeString("zs-endnotes"))).Cons(tr.symAttr))
	for i, fni := range tr.endnotes {

	var result sx.ListBuilder
	result.Add(SymOL)
	result.Add(sx.Nil().Cons(sx.Cons(SymAttrClass, sx.MakeString("zs-endnotes"))).Cons(sxhtml.SymAttr))
	for i, fni := range env.endnotes {
		noteNum := strconv.Itoa(i + 1)
		noteID := tr.unique + noteNum

		attrs := fni.attrs.Cons(sx.Cons(tr.symClass, sx.MakeString("zs-endnote"))).
			Cons(sx.Cons(tr.Make("value"), sx.MakeString(noteNum))).
			Cons(sx.Cons(tr.Make("id"), sx.MakeString("fn:"+noteID))).
			Cons(sx.Cons(tr.Make("role"), sx.MakeString("doc-endnote"))).
			Cons(tr.symAttr)
		attrs := fni.attrs.Cons(sx.Cons(SymAttrClass, sx.MakeString("zs-endnote"))).
			Cons(sx.Cons(SymAttrValue, sx.MakeString(noteNum))).
			Cons(sx.Cons(SymAttrID, sx.MakeString("fn:"+fni.noteID))).
			Cons(sx.Cons(SymAttrRole, sx.MakeString("doc-endnote"))).
			Cons(sxhtml.SymAttr)

		backref := sx.Nil().Cons(sx.MakeString("\u21a9\ufe0e")).
			Cons(sx.Nil().
				Cons(sx.Cons(tr.symClass, sx.MakeString("zs-endnote-backref"))).
				Cons(sx.Cons(tr.Make("href"), sx.MakeString("#fnref:"+noteID))).
				Cons(sx.Cons(tr.Make("role"), sx.MakeString("doc-backlink"))).
				Cons(tr.symAttr)).
			Cons(tr.symA)
				Cons(sx.Cons(SymAttrClass, sx.MakeString("zs-endnote-backref"))).
				Cons(sx.Cons(SymAttrHref, sx.MakeString("#fnref:"+fni.noteID))).
				Cons(sx.Cons(SymAttrRole, sx.MakeString("doc-backlink"))).
				Cons(sxhtml.SymAttr)).
			Cons(SymA)

		li := sx.Nil().Cons(tr.Make("li"))
		li.AppendBang(attrs).
			ExtendBang(fni.noteHx).
			AppendBang(sx.MakeString(" ")).AppendBang(backref)
		currResult = currResult.AppendBang(li)
		var li sx.ListBuilder
		li.Add(SymLI)
		li.Add(attrs)
		li.ExtendBang(fni.noteHx)
		li.Add(sx.MakeString(" "))
		li.Add(backref)
		result.Add(li.List())
	}
	tr.endnotes = nil
	return result
	return result.List()
}

// Environment where sz objects are evaluated to shtml objects
type Environment struct {
	err          error
	langStack    LangStack
	endnotes     []endnoteInfo
	quoteNesting uint
}
type endnoteInfo struct {
	noteID  string    // link id
	noteAST sx.Vector // Endnote as list of AST inline elements
	attrs   *sx.Pair  // attrs a-list
	noteHx  *sx.Pair  // Endnote as SxHTML
}

// TransformEnv is the environment where the actual transformation takes places.
type TransformEnv struct {
// MakeEnvironment builds a new evaluation environment.
func MakeEnvironment(lang string) Environment {
	tr          *Transformer
	astSF       sx.SymbolFactory
	astEnv      sx.Environment
	err         error
	return Environment{
		err:          nil,
	textEnc     *text.Encoder
	symNoEscape *sx.Symbol
	symAttr     *sx.Symbol
	symA        *sx.Symbol
		langStack:    NewLangStack(lang),
		endnotes:     nil,
	symSpan     *sx.Symbol
	symP        *sx.Symbol
}

func (te *TransformEnv) initialize() {
	te.symNoEscape = te.Make(sxhtml.NameSymNoEscape)
	te.symAttr = te.tr.symAttr
	te.symA = te.tr.symA
	te.symSpan = te.tr.symSpan
	te.symP = te.Make("p")
		quoteNesting: 0,
	}
}

// GetError returns the last error found.
func (env *Environment) GetError() error { return env.err }

// Reset the environment.
func (env *Environment) Reset() {
	env.langStack.Reset()
	env.endnotes = nil
	env.quoteNesting = 0
}

// pushAttribute adds the current attributes to the environment.
func (env *Environment) pushAttributes(a attrs.Attributes) {
	if value, ok := a.Get("lang"); ok {
		env.langStack.Push(value)
	} else {
		env.langStack.Dup()
	}
}

// popAttributes removes the current attributes from the envrionment.
func (env *Environment) popAttributes() { env.langStack.Pop() }

// getLanguage returns the current language.
func (env *Environment) getLanguage() string { return env.langStack.Top() }
	te.bind(sz.NameSymList, 0, listArgs)
	te.bindMetadata()
	te.bindBlocks()
	te.bindInlines()
}

func listArgs(args []sx.Object) sx.Object { return sx.MakeList(args...) }

func (te *TransformEnv) bindMetadata() {
	te.bind(sz.NameSymMeta, 0, listArgs)

func (env *Environment) getQuotes() (string, string, bool) {
	qi := GetQuoteInfo(env.getLanguage())
	leftQ, rightQ := qi.GetQuotes(env.quoteNesting)
	return leftQ, rightQ, qi.GetNBSp()
}

// EvalFn is a function to be called for evaluation.
type EvalFn func(sx.Vector, *Environment) sx.Object

func (ev *Evaluator) bind(sym *sx.Symbol, minArgs int, fn EvalFn) {
	symVal := sym.GetValue()
	ev.fns[symVal] = fn
	if minArgs > 0 {
		ev.minArgs[symVal] = minArgs
	}
}

// ResolveBinding returns the function bound to the given name.
func (ev *Evaluator) ResolveBinding(sym *sx.Symbol) EvalFn {
	if fn, found := ev.fns[sym.GetValue()]; found {
		return fn
	}
	return nil
}

// Rebind overwrites a binding, but leaves the minimum number of arguments intact.
func (ev *Evaluator) Rebind(sym *sx.Symbol, fn EvalFn) {
	symVal := sym.GetValue()
	if _, found := ev.fns[symVal]; !found {
		panic(sym)
	}
	ev.fns[symVal] = fn
}

func (ev *Evaluator) bindMetadata() {
	ev.bind(sz.SymMeta, 0, ev.evalList)
	te.bind(sz.NameSymTypeZettelmarkup, 2, func(args []sx.Object) sx.Object {
		a := make(attrs.Attributes, 2).
			Set("name", te.getSymbol(args[0]).String()).
			Set("content", te.textEnc.Encode(te.getList(args[1])))
		return te.transformMeta(a)
	})
	metaString := func(args []sx.Object) sx.Object {
	evalMetaString := func(args sx.Vector, env *Environment) sx.Object {
		a := make(attrs.Attributes, 2).
			Set("name", te.getSymbol(args[0]).Name()).
			Set("content", te.getString(args[1]).String())
		return te.transformMeta(a)
			Set("name", getSymbol(args[0], env).GetValue()).
			Set("content", getString(args[1], env).GetValue())
		return ev.EvaluateMeta(a)
	}
	te.bind(sz.NameSymTypeCredential, 2, metaString)
	te.bind(sz.NameSymTypeEmpty, 2, metaString)
	te.bind(sz.NameSymTypeID, 2, metaString)
	te.bind(sz.NameSymTypeNumber, 2, metaString)
	te.bind(sz.NameSymTypeString, 2, metaString)
	te.bind(sz.NameSymTypeTimestamp, 2, metaString)
	te.bind(sz.NameSymTypeURL, 2, metaString)
	te.bind(sz.NameSymTypeWord, 2, metaString)
	metaSet := func(args []sx.Object) sx.Object {
	ev.bind(sz.SymTypeCredential, 2, evalMetaString)
	ev.bind(sz.SymTypeEmpty, 2, evalMetaString)
	ev.bind(sz.SymTypeID, 2, evalMetaString)
	ev.bind(sz.SymTypeNumber, 2, evalMetaString)
	ev.bind(sz.SymTypeString, 2, evalMetaString)
	ev.bind(sz.SymTypeTimestamp, 2, evalMetaString)
	ev.bind(sz.SymTypeURL, 2, evalMetaString)
	ev.bind(sz.SymTypeWord, 2, evalMetaString)

	evalMetaSet := func(args sx.Vector, env *Environment) sx.Object {
		var sb strings.Builder
		for elem := te.getList(args[1]); elem != nil; elem = elem.Tail() {
		for elem := getList(args[1], env); elem != nil; elem = elem.Tail() {
			sb.WriteByte(' ')
			sb.WriteString(te.getString(elem.Car()).String())
			sb.WriteString(getString(elem.Car(), env).GetValue())
		}
		s := sb.String()
		if len(s) > 0 {
			s = s[1:]
		}
		a := make(attrs.Attributes, 2).
			Set("name", te.getSymbol(args[0]).Name()).
			Set("name", getSymbol(args[0], env).GetValue()).
			Set("content", s)
		return te.transformMeta(a)
		return ev.EvaluateMeta(a)
	}
	te.bind(sz.NameSymTypeIDSet, 2, metaSet)
	te.bind(sz.NameSymTypeTagSet, 2, metaSet)
	te.bind(sz.NameSymTypeWordSet, 2, metaSet)
	ev.bind(sz.SymTypeIDSet, 2, evalMetaSet)
	ev.bind(sz.SymTypeTagSet, 2, evalMetaSet)
	ev.bind(sz.SymTypeZettelmarkup, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := make(attrs.Attributes, 2).
			Set("name", getSymbol(args[0], env).GetValue()).
			Set("content", text.EvaluateInlineString(getList(args[1], env)))
		return ev.EvaluateMeta(a)
	})
}

// EvaluateMeta returns HTML meta object for an attribute.
func (ev *Evaluator) EvaluateMeta(a attrs.Attributes) *sx.Pair {
	return sx.Nil().Cons(EvaluateAttrbute(a)).Cons(SymMeta)
}

func (te *TransformEnv) bindBlocks() {
	te.bind(sz.NameSymBlock, 0, listArgs)
	te.bind(sz.NameSymPara, 0, func(args []sx.Object) sx.Object {
func (ev *Evaluator) bindBlocks() {
	ev.bind(sz.SymBlock, 0, ev.evalList)
	ev.bind(sz.SymPara, 0, func(args sx.Vector, env *Environment) sx.Object {
		// for ; args != nil; args = args.Tail() {
		// 	lst, ok := sx.GetList(args.Car())
		// 	if !ok || lst != nil {
		// 		break
		// 	}
		// }
		return sx.MakeList(args...).Cons(te.symP)
		return ev.evalSlice(args, env).Cons(SymP)
	})
	te.bind(sz.NameSymHeading, 5, func(args []sx.Object) sx.Object {
		nLevel := te.getInt64(args[0])
	ev.bind(sz.SymHeading, 5, func(args sx.Vector, env *Environment) sx.Object {
		nLevel := getInt64(args[0], env)
		if nLevel <= 0 {
			te.err = fmt.Errorf("%v is a negative level", nLevel)
			env.err = fmt.Errorf("%v is a negative heading level", nLevel)
			return sx.Nil()
		}
		level := strconv.FormatInt(nLevel+te.tr.headingOffset, 10)
		level := strconv.FormatInt(nLevel+ev.headingOffset, 10)
		headingSymbol := sx.MakeSymbol("h" + level)

		a := te.getAttributes(args[1])
		if fragment := te.getString(args[3]).String(); fragment != "" {
			a = a.Set("id", te.tr.unique+fragment)
		a := GetAttributes(args[1], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		if fragment := getString(args[3], env).GetValue(); fragment != "" {
			a = a.Set("id", ev.unique+fragment)
		}

		if result, isPair := sx.GetPair(args[4]); isPair && result != nil {
		if result, _ := ev.EvaluateList(args[4:], env); result != nil {
			if len(a) > 0 {
				result = result.Cons(te.transformAttribute(a))
				result = result.Cons(EvaluateAttrbute(a))
			}
			return result.Cons(te.Make("h" + level))
			return result.Cons(headingSymbol)
		}
		return sx.MakeList(te.Make("h"+level), sx.MakeString("<MISSING TEXT>"))
		return sx.MakeList(headingSymbol, sx.MakeString("<MISSING TEXT>"))
	})
	te.bind(sz.NameSymThematic, 0, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymThematic, 0, func(args sx.Vector, env *Environment) sx.Object {
		result := sx.Nil()
		if len(args) > 0 {
			if attrList := te.getList(args[0]); attrList != nil {
				result = result.Cons(te.transformAttribute(sz.GetAttributes(attrList)))
			if attrList := getList(args[0], env); attrList != nil {
				result = result.Cons(EvaluateAttrbute(sz.GetAttributes(attrList)))
			}
		}
		return result.Cons(te.Make("hr"))
		return result.Cons(SymHR)
	})

	te.bind(sz.NameSymListOrdered, 0, te.makeListFn("ol"))
	te.bind(sz.NameSymListUnordered, 0, te.makeListFn("ul"))
	te.bind(sz.NameSymDescription, 0, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymListOrdered, 0, ev.makeListFn(SymOL))
	ev.bind(sz.SymListUnordered, 0, ev.makeListFn(SymUL))
	ev.bind(sz.SymDescription, 0, func(args sx.Vector, env *Environment) sx.Object {
		if len(args) == 0 {
			return sx.Nil()
		}
		items := sx.Nil().Cons(te.Make("dl"))
		curItem := items
		var items sx.ListBuilder
		items.Add(symDL)
		for pos := 0; pos < len(args); pos++ {
			term := te.getList(args[pos])
			curItem = curItem.AppendBang(term.Cons(te.Make("dt")))
			term := ev.evalDescriptionTerm(getList(args[pos], env), env)
			items.Add(term.Cons(symDT))
			pos++
			if pos >= len(args) {
				break
			}
			ddBlock := te.getList(args[pos])
			ddBlock := getList(ev.Eval(args[pos], env), env)
			if ddBlock == nil {
				break
				continue
			}
			for ddlst := ddBlock; ddlst != nil; ddlst = ddlst.Tail() {
				dditem := te.getList(ddlst.Car())
				curItem = curItem.AppendBang(dditem.Cons(te.Make("dd")))
				dditem := getList(ddlst.Car(), env)
				items.Add(dditem.Cons(symDD))
			}
		}
		return items
		return items.List()
	})

	te.bind(sz.NameSymListQuote, 0, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymListQuote, 0, func(args sx.Vector, env *Environment) sx.Object {
		if args == nil {
			return sx.Nil()
		}
		result := sx.Nil().Cons(te.Make("blockquote"))
		currResult := result
		var result sx.ListBuilder
		result.Add(symBLOCKQUOTE)
		for _, elem := range args {
			if quote, isPair := sx.GetPair(elem); isPair {
				currResult = currResult.AppendBang(quote.Cons(te.symP))
			if quote, isPair := sx.GetPair(ev.Eval(elem, env)); isPair {
				result.Add(quote.Cons(sxhtml.SymListSplice))
			}
		}
		return result
		return result.List()
	})

	te.bind(sz.NameSymTable, 1, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymTable, 1, func(args sx.Vector, env *Environment) sx.Object {
		thead := sx.Nil()
		if header := te.getList(args[0]); !sx.IsNil(header) {
			thead = sx.Nil().Cons(te.transformTableRow(header)).Cons(te.Make("thead"))
		if header := getList(args[0], env); !sx.IsNil(header) {
			thead = sx.Nil().Cons(ev.evalTableRow(symTH, header, env)).Cons(symTHEAD)
		}

		tbody := sx.Nil()
		var tbody sx.ListBuilder
		if len(args) > 1 {
			tbody = sx.Nil().Cons(te.Make("tbody"))
			curBody := tbody
			tbody.Add(symTBODY)
			for _, row := range args[1:] {
				curBody = curBody.AppendBang(te.transformTableRow(te.getList(row)))
				tbody.Add(ev.evalTableRow(symTD, getList(row, env), env))
			}
		}

		table := sx.Nil()
		if tbody != nil {
			table = table.Cons(tbody)
		if !tbody.IsEmpty() {
			table = table.Cons(tbody.List())
		}
		if thead != nil {
			table = table.Cons(thead)
		}
		if table == nil {
			return sx.Nil()
		}
		return table.Cons(te.Make("table"))
		return table.Cons(symTABLE)
	})
	te.bind(sz.NameSymCell, 0, te.makeCellFn(""))
	te.bind(sz.NameSymCellCenter, 0, te.makeCellFn("center"))
	te.bind(sz.NameSymCellLeft, 0, te.makeCellFn("left"))
	te.bind(sz.NameSymCellRight, 0, te.makeCellFn("right"))
	ev.bind(sz.SymCell, 0, ev.makeCellFn(""))
	ev.bind(sz.SymCellCenter, 0, ev.makeCellFn("center"))
	ev.bind(sz.SymCellLeft, 0, ev.makeCellFn("left"))
	ev.bind(sz.SymCellRight, 0, ev.makeCellFn("right"))

	te.bind(sz.NameSymRegionBlock, 2, te.makeRegionFn(te.Make("div"), true))
	te.bind(sz.NameSymRegionQuote, 2, te.makeRegionFn(te.Make("blockquote"), false))
	te.bind(sz.NameSymRegionVerse, 2, te.makeRegionFn(te.Make("div"), false))
	ev.bind(sz.SymRegionBlock, 2, ev.makeRegionFn(SymDIV, true))
	ev.bind(sz.SymRegionQuote, 2, ev.makeRegionFn(symBLOCKQUOTE, false))
	ev.bind(sz.SymRegionVerse, 2, ev.makeRegionFn(SymDIV, false))

	te.bind(sz.NameSymVerbatimComment, 1, func(args []sx.Object) sx.Object {
		if te.getAttributes(args[0]).HasDefault() {
	ev.bind(sz.SymVerbatimComment, 1, func(args sx.Vector, env *Environment) sx.Object {
		if GetAttributes(args[0], env).HasDefault() {
			if len(args) > 1 {
				if s := te.getString(args[1]); s != "" {
				if s := getString(args[1], env); s.GetValue() != "" {
					t := sx.MakeString(s.String())
					return sx.Nil().Cons(t).Cons(te.Make(sxhtml.NameSymBlockComment))
					return sx.Nil().Cons(s).Cons(sxhtml.SymBlockComment)
				}
			}
		}
		return nil
	})

	te.bind(sz.NameSymVerbatimEval, 2, func(args []sx.Object) sx.Object {
		return te.transformVerbatim(te.getAttributes(args[0]).AddClass("zs-eval"), te.getString(args[1]))
	ev.bind(sz.SymVerbatimEval, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalVerbatim(GetAttributes(args[0], env).AddClass("zs-eval"), getString(args[1], env))
	})
	te.bind(sz.NameSymVerbatimHTML, 2, te.transformHTML)
	te.bind(sz.NameSymVerbatimMath, 2, func(args []sx.Object) sx.Object {
		return te.transformVerbatim(te.getAttributes(args[0]).AddClass("zs-math"), te.getString(args[1]))
	ev.bind(sz.SymVerbatimHTML, 2, ev.evalHTML)
	ev.bind(sz.SymVerbatimMath, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalVerbatim(GetAttributes(args[0], env).AddClass("zs-math"), getString(args[1], env))
	})
	te.bind(sz.NameSymVerbatimProg, 2, func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
		content := te.getString(args[1])
	ev.bind(sz.SymVerbatimProg, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		content := getString(args[1], env)
		if a.HasDefault() {
			content = sx.MakeString(visibleReplacer.Replace(content.String()))
			content = sx.MakeString(visibleReplacer.Replace(content.GetValue()))
		}
		return te.transformVerbatim(a, content)
		return evalVerbatim(a, content)
	})
	te.bind(sz.NameSymVerbatimZettel, 0, func([]sx.Object) sx.Object { return sx.Nil() })

	ev.bind(sz.SymVerbatimZettel, 0, nilFn)
	ev.bind(sz.SymBLOB, 3, func(args sx.Vector, env *Environment) sx.Object {
	te.bind(sz.NameSymBLOB, 3, func(args []sx.Object) sx.Object {
		return te.transformBLOB(te.getList(args[0]), te.getString(args[1]), te.getString(args[2]))
		return evalBLOB(getList(args[0], env), getString(args[1], env), getString(args[2], env))
	})

	te.bind(sz.NameSymTransclude, 2, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymTransclude, 2, func(args sx.Vector, env *Environment) sx.Object {
		ref, isPair := sx.GetPair(args[1])
		if !isPair {
			return sx.Nil()
		}
		refKind := ref.Car()
		if sx.IsNil(refKind) {
			return sx.Nil()
		}
		if refValue := te.getString(ref.Tail().Car()); refValue != "" {
			if te.astSF.MustMake(sz.NameSymRefStateExternal).IsEqual(refKind) {
				a := te.getAttributes(args[0]).Set("src", refValue.String()).AddClass("external")
				return sx.Nil().Cons(sx.Nil().Cons(te.transformAttribute(a)).Cons(te.Make("img"))).Cons(te.symP)
		if refValue := getString(ref.Tail().Car(), env); refValue.GetValue() != "" {
			if refSym, isRefSym := sx.GetSymbol(refKind); isRefSym && refSym.IsEqualSymbol(sz.SymRefStateExternal) {
				a := GetAttributes(args[0], env).Set("src", refValue.GetValue()).AddClass("external")
				return sx.Nil().Cons(sx.Nil().Cons(EvaluateAttrbute(a)).Cons(SymIMG)).Cons(SymP)
			}
			return sx.MakeList(
				te.Make(sxhtml.NameSymInlineComment),
				sxhtml.SymInlineComment,
				sx.MakeString("transclude"),
				refKind,
				sx.MakeString("->"),
				refValue,
			)
		}
		return sx.MakeList(args...)
		return ev.evalSlice(args, env)
	})
}

func (te *TransformEnv) makeListFn(tag string) transformFn {
func (ev *Evaluator) makeListFn(sym *sx.Symbol) EvalFn {
	sym := te.Make(tag)
	return func(args []sx.Object) sx.Object {
		result := sx.Nil().Cons(sym)
		last := result
	return func(args sx.Vector, env *Environment) sx.Object {
		var result sx.ListBuilder
		result.Add(sym)
		for _, elem := range args {
			item := sx.Nil().Cons(te.Make("li"))
			if res, isPair := sx.GetPair(elem); isPair {
			item := sx.Nil().Cons(SymLI)
			if res, isPair := sx.GetPair(ev.Eval(elem, env)); isPair {
				item.ExtendBang(res)
			}
			last = last.AppendBang(item)
			result.Add(item)
		}
		return result
		return result.List()
	}
}
func (te *TransformEnv) transformTableRow(pairs *sx.Pair) *sx.Pair {
	row := sx.Nil().Cons(te.Make("tr"))

func (ev *Evaluator) evalDescriptionTerm(term *sx.Pair, env *Environment) *sx.Pair {
	var result sx.ListBuilder
	for node := term; node != nil; node = node.Tail() {
		elem := ev.Eval(node.Car(), env)
		result.Add(elem)
	}
	return result.List()
}

func (ev *Evaluator) evalTableRow(sym *sx.Symbol, pairs *sx.Pair, env *Environment) *sx.Pair {
	if pairs == nil {
		return nil
	}
	curRow := row
	var row sx.ListBuilder
	row.Add(symTR)
	for pair := pairs; pair != nil; pair = pair.Tail() {
		curRow = curRow.AppendBang(pair.Car())
		row.Add(sx.Cons(sym, ev.Eval(pair.Car(), env)))
	}
	return row
	return row.List()
}

func (te *TransformEnv) makeCellFn(align string) transformFn {
	return func(args []sx.Object) sx.Object {
		tdata := sx.MakeList(args...)
func (ev *Evaluator) makeCellFn(align string) EvalFn {
	return func(args sx.Vector, env *Environment) sx.Object {
		tdata := ev.evalSlice(args, env)
		if align != "" {
			tdata = tdata.Cons(te.transformAttribute(attrs.Attributes{"class": align}))
			tdata = tdata.Cons(EvaluateAttrbute(attrs.Attributes{"class": align}))
		}
		return tdata.Cons(te.Make("td"))
		return tdata
	}
}

func (te *TransformEnv) makeRegionFn(sym *sx.Symbol, genericToClass bool) transformFn {
	return func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
func (ev *Evaluator) makeRegionFn(sym *sx.Symbol, genericToClass bool) EvalFn {
	return func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		if genericToClass {
			if val, found := a.Get(""); found {
				a = a.Remove("").AddClass(val)
			}
		}
		var result sx.ListBuilder
		result := sx.Nil()
		result.Add(sym)
		if len(a) > 0 {
			result = result.Cons(te.transformAttribute(a))
			result.Add(EvaluateAttrbute(a))
		}
		result = result.Cons(sym)
		currResult := result.LastPair()
		if region, isPair := sx.GetPair(args[1]); isPair {
			if evalRegion := ev.EvalPairList(region, env); evalRegion != nil {
			currResult = currResult.ExtendBang(region)
		}
				result.ExtendBang(evalRegion)
			}
		}
		if len(args) > 2 {
			if cite, isPair := sx.GetPair(args[2]); isPair && cite != nil {
				currResult.AppendBang(cite.Cons(te.Make("cite")))
			if cite, _ := ev.EvaluateList(args[2:], env); cite != nil {
				result.Add(cite.Cons(symCITE))
			}
		}
		return result
		return result.List()
	}
}

func (te *TransformEnv) transformVerbatim(a attrs.Attributes, s sx.String) sx.Object {
func evalVerbatim(a attrs.Attributes, s sx.String) sx.Object {
	a = setProgLang(a)
	code := sx.Nil().Cons(s)
	if al := te.transformAttribute(a); al != nil {
	if al := EvaluateAttrbute(a); al != nil {
		code = code.Cons(al)
	}
	code = code.Cons(te.Make("code"))
	return sx.Nil().Cons(code).Cons(te.Make("pre"))
	code = code.Cons(symCODE)
	return sx.Nil().Cons(code).Cons(symPRE)
}

func (te *TransformEnv) bindInlines() {
	te.bind(sz.NameSymInline, 0, listArgs)
	te.bind(sz.NameSymText, 1, func(args []sx.Object) sx.Object { return te.getString(args[0]) })
func (ev *Evaluator) bindInlines() {
	ev.bind(sz.SymInline, 0, ev.evalList)
	ev.bind(sz.SymText, 1, func(args sx.Vector, env *Environment) sx.Object { return getString(args[0], env) })
	te.bind(sz.NameSymSpace, 0, func(args []sx.Object) sx.Object {
		if len(args) == 0 {
			return sx.MakeString(" ")
		}
		return te.getString(args[0])
	})
	te.bind(sz.NameSymSoft, 0, func([]sx.Object) sx.Object { return sx.MakeString(" ") })
	ev.bind(sz.SymSoft, 0, func(sx.Vector, *Environment) sx.Object { return sx.MakeString(" ") })
	brSym := te.Make("br")
	te.bind(sz.NameSymHard, 0, func([]sx.Object) sx.Object { return sx.Nil().Cons(brSym) })
	ev.bind(sz.SymHard, 0, func(sx.Vector, *Environment) sx.Object { return sx.Nil().Cons(symBR) })

	te.bind(sz.NameSymLinkInvalid, 2, func(args []sx.Object) sx.Object {
		// a := te.getAttributes(args)
	ev.bind(sz.SymLinkInvalid, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		var inline *sx.Pair
		if len(args) > 2 {
			inline = sx.MakeList(args[2:]...)
			inline = ev.evalSlice(args[2:], env)
		}
		if inline == nil {
			inline = sx.Nil().Cons(args[1])
			inline = sx.Nil().Cons(ev.Eval(args[1], env))
		}
		return inline.Cons(te.symSpan)
		return inline.Cons(SymSPAN)
	})
	transformHREF := func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
		refValue := te.getString(args[1])
		return te.transformLink(a.Set("href", refValue.String()), refValue, args[2:])
	evalHREF := func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		refValue := getString(args[1], env)
		return ev.evalLink(a.Set("href", refValue.GetValue()), refValue, args[2:], env)
	}
	te.bind(sz.NameSymLinkZettel, 2, transformHREF)
	te.bind(sz.NameSymLinkSelf, 2, transformHREF)
	te.bind(sz.NameSymLinkFound, 2, transformHREF)
	te.bind(sz.NameSymLinkBroken, 2, func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
		refValue := te.getString(args[1])
		return te.transformLink(a.AddClass("broken"), refValue, args[2:])
	ev.bind(sz.SymLinkZettel, 2, evalHREF)
	ev.bind(sz.SymLinkSelf, 2, evalHREF)
	ev.bind(sz.SymLinkFound, 2, evalHREF)
	ev.bind(sz.SymLinkBroken, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		refValue := getString(args[1], env)
		return ev.evalLink(a.AddClass("broken"), refValue, args[2:], env)
	})
	te.bind(sz.NameSymLinkHosted, 2, transformHREF)
	te.bind(sz.NameSymLinkBased, 2, transformHREF)
	te.bind(sz.NameSymLinkQuery, 2, func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
		refValue := te.getString(args[1])
		query := "?" + api.QueryKeyQuery + "=" + url.QueryEscape(refValue.String())
		return te.transformLink(a.Set("href", query), refValue, args[2:])
	ev.bind(sz.SymLinkHosted, 2, evalHREF)
	ev.bind(sz.SymLinkBased, 2, evalHREF)
	ev.bind(sz.SymLinkQuery, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		refValue := getString(args[1], env)
		query := "?" + api.QueryKeyQuery + "=" + url.QueryEscape(refValue.GetValue())
		return ev.evalLink(a.Set("href", query), refValue, args[2:], env)
	})
	te.bind(sz.NameSymLinkExternal, 2, func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
		refValue := te.getString(args[1])
		return te.transformLink(a.Set("href", refValue.String()).AddClass("external"), refValue, args[2:])
	})

	te.bind(sz.NameSymEmbed, 3, func(args []sx.Object) sx.Object {
		ref := te.getList(args[1])
	ev.bind(sz.SymLinkExternal, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		syntax := te.getString(args[2])
		if syntax == api.ValueSyntaxSVG {
			embedAttr := sx.MakeList(
				te.symAttr,
		env.pushAttributes(a)
		defer env.popAttributes()
				sx.Cons(te.Make("type"), sx.MakeString("image/svg+xml")),
				sx.Cons(te.Make("src"), sx.MakeString("/"+te.getString(ref.Tail()).String()+".svg")),
			)
		refValue := getString(args[1], env)
		return ev.evalLink(a.Set("href", refValue.GetValue()).Add("rel", "external"), refValue, args[2:], env)
	})

			return sx.MakeList(
				te.Make("figure"),
				sx.MakeList(
	ev.bind(sz.SymEmbed, 3, func(args sx.Vector, env *Environment) sx.Object {
		ref := getList(args[1], env)
					te.Make("embed"),
					embedAttr,
				),
			)
		}
		a := te.getAttributes(args[0])
		a = a.Set("src", string(te.getString(ref.Tail().Car())))
		var sb strings.Builder
		te.flattenText(&sb, ref.Tail().Tail().Tail())
		if d := sb.String(); d != "" {
			a = a.Set("alt", d)
		}
		return sx.MakeList(te.Make("img"), te.transformAttribute(a))
		a := GetAttributes(args[0], env)
		a = a.Set("src", getString(ref.Tail().Car(), env).GetValue())
		if len(args) > 3 {
			var sb strings.Builder
			flattenText(&sb, sx.MakeList(args[3:]...))
			if d := sb.String(); d != "" {
				a = a.Set("alt", d)
			}
		}
		return sx.MakeList(SymIMG, EvaluateAttrbute(a))
	})
	te.bind(sz.NameSymEmbedBLOB, 3, func(args []sx.Object) sx.Object {
		a, syntax, data := te.getAttributes(args[0]), te.getString(args[1]), te.getString(args[2])
		summary, _ := a.Get(api.KeySummary)
		return te.transformBLOB(
			sx.MakeList(te.astSF.MustMake(sz.NameSymInline), sx.MakeString(summary)),
	ev.bind(sz.SymEmbedBLOB, 3, func(args sx.Vector, env *Environment) sx.Object {
		a, syntax, data := GetAttributes(args[0], env), getString(args[1], env), getString(args[2], env)
		summary, hasSummary := a.Get(api.KeySummary)
		if !hasSummary {
			summary = ""
		}
		return evalBLOB(
			sx.MakeList(sxhtml.SymListSplice, sx.MakeString(summary)),
			syntax,
			data,
		)
	})

	te.bind(sz.NameSymCite, 2, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymCite, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		result := sx.Nil()
		if key := te.getString(args[1]); key != "" {
		if key := getString(args[1], env); key.GetValue() != "" {
			if len(args) > 2 {
				result = sx.MakeList(args[2:]...).Cons(sx.MakeString(", "))
				result = ev.evalSlice(args[2:], env).Cons(sx.MakeString(", "))
			}
			result = result.Cons(key)
		}
		if a := te.getAttributes(args[0]); len(a) > 0 {
			result = result.Cons(te.transformAttribute(a))
		if len(a) > 0 {
			result = result.Cons(EvaluateAttrbute(a))
		}
		if result == nil {
			return nil
		}
		return result.Cons(te.symSpan)
		return result.Cons(SymSPAN)
	})

	ev.bind(sz.SymMark, 3, func(args sx.Vector, env *Environment) sx.Object {
	te.bind(sz.NameSymMark, 3, func(args []sx.Object) sx.Object {
		result := sx.MakeList(args[3:]...)
		if !te.tr.noLinks {
			if fragment := te.getString(args[2]); fragment != "" {
				a := attrs.Attributes{"id": fragment.String() + te.tr.unique}
				return result.Cons(te.transformAttribute(a)).Cons(te.symA)
		result := ev.evalSlice(args[3:], env)
		if !ev.noLinks {
			if fragment := getString(args[2], env).GetValue(); fragment != "" {
				a := attrs.Attributes{"id": fragment + ev.unique}
				return result.Cons(EvaluateAttrbute(a)).Cons(SymA)
			}
		}
		return result.Cons(te.symSpan)
		return result.Cons(SymSPAN)
	})

	te.bind(sz.NameSymEndnote, 1, func(args []sx.Object) sx.Object {
	ev.bind(sz.SymEndnote, 1, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env)
		env.pushAttributes(a)
		defer env.popAttributes()
		attrPlist := sx.Nil()
		if a := te.getAttributes(args[0]); len(a) > 0 {
			if attrs := te.transformAttribute(a); attrs != nil {
		if len(a) > 0 {
			if attrs := EvaluateAttrbute(a); attrs != nil {
				attrPlist = attrs.Tail()
			}
		}

		text, isPair := sx.GetPair(args[1])
		if !isPair {
			return sx.Nil()
		}
		te.tr.endnotes = append(te.tr.endnotes, endnoteInfo{noteAST: text, noteHx: nil, attrs: attrPlist})
		noteNum := strconv.Itoa(len(te.tr.endnotes))
		noteID := te.tr.unique + noteNum
		hrefAttr := sx.Nil().Cons(sx.Cons(te.Make("role"), sx.MakeString("doc-noteref"))).
			Cons(sx.Cons(te.Make("href"), sx.MakeString("#fn:"+noteID))).
			Cons(sx.Cons(te.tr.symClass, sx.MakeString("zs-noteref"))).
			Cons(te.symAttr)
		href := sx.Nil().Cons(sx.MakeString(noteNum)).Cons(hrefAttr).Cons(te.symA)
		supAttr := sx.Nil().Cons(sx.Cons(te.Make("id"), sx.MakeString("fnref:"+noteID))).Cons(te.symAttr)
		return sx.Nil().Cons(href).Cons(supAttr).Cons(te.Make("sup"))
		noteNum := strconv.Itoa(len(env.endnotes) + 1)
		noteID := ev.unique + noteNum
		env.endnotes = append(env.endnotes, endnoteInfo{
			noteID: noteID, noteAST: args[1:], noteHx: nil, attrs: attrPlist})
		hrefAttr := sx.Nil().Cons(sx.Cons(SymAttrRole, sx.MakeString("doc-noteref"))).
			Cons(sx.Cons(SymAttrHref, sx.MakeString("#fn:"+noteID))).
			Cons(sx.Cons(SymAttrClass, sx.MakeString("zs-noteref"))).
			Cons(sxhtml.SymAttr)
		href := sx.Nil().Cons(sx.MakeString(noteNum)).Cons(hrefAttr).Cons(SymA)
		supAttr := sx.Nil().Cons(sx.Cons(SymAttrID, sx.MakeString("fnref:"+noteID))).Cons(sxhtml.SymAttr)
		return sx.Nil().Cons(href).Cons(supAttr).Cons(symSUP)
	})

	te.bind(sz.NameSymFormatDelete, 1, te.makeFormatFn("del"))
	te.bind(sz.NameSymFormatEmph, 1, te.makeFormatFn("em"))
	te.bind(sz.NameSymFormatInsert, 1, te.makeFormatFn("ins"))
	te.bind(sz.NameSymFormatQuote, 1, te.transformQuote)
	te.bind(sz.NameSymFormatSpan, 1, te.makeFormatFn("span"))
	te.bind(sz.NameSymFormatStrong, 1, te.makeFormatFn("strong"))
	te.bind(sz.NameSymFormatSub, 1, te.makeFormatFn("sub"))
	te.bind(sz.NameSymFormatSuper, 1, te.makeFormatFn("sup"))
	ev.bind(sz.SymFormatDelete, 1, ev.makeFormatFn(symDEL))
	ev.bind(sz.SymFormatEmph, 1, ev.makeFormatFn(symEM))
	ev.bind(sz.SymFormatInsert, 1, ev.makeFormatFn(symINS))
	ev.bind(sz.SymFormatMark, 1, ev.makeFormatFn(symMARK))
	ev.bind(sz.SymFormatQuote, 1, ev.evalQuote)
	ev.bind(sz.SymFormatSpan, 1, ev.makeFormatFn(SymSPAN))
	ev.bind(sz.SymFormatStrong, 1, ev.makeFormatFn(SymSTRONG))
	ev.bind(sz.SymFormatSub, 1, ev.makeFormatFn(symSUB))
	ev.bind(sz.SymFormatSuper, 1, ev.makeFormatFn(symSUP))

	te.bind(sz.NameSymLiteralComment, 1, func(args []sx.Object) sx.Object {
		if te.getAttributes(args[0]).HasDefault() {
	ev.bind(sz.SymLiteralComment, 1, func(args sx.Vector, env *Environment) sx.Object {
		if GetAttributes(args[0], env).HasDefault() {
			if len(args) > 1 {
				if s := te.getString(args[1]); s != "" {
					return sx.Nil().Cons(s).Cons(te.Make(sxhtml.NameSymInlineComment))
				if s := getString(ev.Eval(args[1], env), env); s.GetValue() != "" {
					return sx.Nil().Cons(s).Cons(sxhtml.SymInlineComment)
				}
			}
		}
		return sx.Nil()
	})
	te.bind(sz.NameSymLiteralHTML, 2, te.transformHTML)
	ev.bind(sz.SymLiteralHTML, 2, ev.evalHTML)
	kbdSym := te.Make("kbd")
	te.bind(sz.NameSymLiteralInput, 2, func(args []sx.Object) sx.Object {
		return te.transformLiteral(args, nil, kbdSym)
	ev.bind(sz.SymLiteralInput, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalLiteral(args, nil, symKBD, env)
	})
	codeSym := te.Make("code")
	te.bind(sz.NameSymLiteralMath, 2, func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0]).AddClass("zs-math")
		return te.transformLiteral(args, a, codeSym)
	ev.bind(sz.SymLiteralMath, 2, func(args sx.Vector, env *Environment) sx.Object {
		a := GetAttributes(args[0], env).AddClass("zs-math")
		return evalLiteral(args, a, symCODE, env)
	})
	sampSym := te.Make("samp")
	te.bind(sz.NameSymLiteralOutput, 2, func(args []sx.Object) sx.Object {
		return te.transformLiteral(args, nil, sampSym)
	ev.bind(sz.SymLiteralOutput, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalLiteral(args, nil, symSAMP, env)
	})
	te.bind(sz.NameSymLiteralProg, 2, func(args []sx.Object) sx.Object {
		return te.transformLiteral(args, nil, codeSym)
	ev.bind(sz.SymLiteralProg, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalLiteral(args, nil, symCODE, env)
	})

	ev.bind(sz.SymLiteralZettel, 0, nilFn)
}


	te.bind(sz.NameSymLiteralZettel, 0, func([]sx.Object) sx.Object { return sx.Nil() })
func (ev *Evaluator) makeFormatFn(sym *sx.Symbol) EvalFn {
	return func(args sx.Vector, env *Environment) sx.Object {
}

		a := GetAttributes(args[0], env)
func (te *TransformEnv) makeFormatFn(tag string) transformFn {
	sym := te.Make(tag)
		env.pushAttributes(a)
	return func(args []sx.Object) sx.Object {
		a := te.getAttributes(args[0])
		if val, found := a.Get(""); found {
		defer env.popAttributes()
		if val, hasClass := a.Get(""); hasClass {
			a = a.Remove("").AddClass(val)
		}
		res := sx.MakeList(args[1:]...)
		res := ev.evalSlice(args[1:], env)
		if len(a) > 0 {
			res = res.Cons(te.transformAttribute(a))
			res = res.Cons(EvaluateAttrbute(a))
		}
		return res.Cons(sym)
	}
}
func (te *TransformEnv) transformQuote(args []sx.Object) sx.Object {
	const langAttr = "lang"
	a := te.getAttributes(args[0])

func (ev *Evaluator) evalQuote(args sx.Vector, env *Environment) sx.Object {
	a := GetAttributes(args[0], env)
	env.pushAttributes(a)
	defer env.popAttributes()
	langVal, found := a.Get(langAttr)
	if found {
		a = a.Remove(langAttr)
	}
	if val, found2 := a.Get(""); found2 {

	if val, hasClass := a.Get(""); hasClass {
		a = a.Remove("").AddClass(val)
	}
	leftQ, rightQ, withNbsp := env.getQuotes()
	res := sx.MakeList(args[1:]...)
	if len(a) > 0 {
		res = res.Cons(te.transformAttribute(a))
	}
	res = res.Cons(te.Make("q"))

	env.quoteNesting++
	res := ev.evalSlice(args[1:], env)
	env.quoteNesting--

	lastPair := res.LastPair()
	if lastPair.IsNil() {
		res = sx.Cons(sx.MakeList(sxhtml.SymNoEscape, sx.MakeString(leftQ), sx.MakeString(rightQ)), sx.Nil())
	} else {
		if withNbsp {
			lastPair.AppendBang(sx.MakeList(sxhtml.SymNoEscape, sx.MakeString("&nbsp;"), sx.MakeString(rightQ)))
			res = res.Cons(sx.MakeList(sxhtml.SymNoEscape, sx.MakeString(leftQ), sx.MakeString("&nbsp;")))
		} else {
			lastPair.AppendBang(sx.MakeList(sxhtml.SymNoEscape, sx.MakeString(rightQ)))
			res = res.Cons(sx.MakeList(sxhtml.SymNoEscape, sx.MakeString(leftQ)))
		}
	}
	if len(a) > 0 {
		res = res.Cons(EvaluateAttrbute(a))
	if found {
		res = sx.Nil().Cons(res).Cons(te.transformAttribute(attrs.Attributes{}.Set(langAttr, langVal))).Cons(te.symSpan)
		return res.Cons(SymSPAN)
	}
	return res
	return res.Cons(sxhtml.SymListSplice)
}

var visibleReplacer = strings.NewReplacer(" ", "\u2423")

func (te *TransformEnv) transformLiteral(args []sx.Object, a attrs.Attributes, sym *sx.Symbol) sx.Object {
func evalLiteral(args sx.Vector, a attrs.Attributes, sym *sx.Symbol, env *Environment) sx.Object {
	if a == nil {
		a = te.getAttributes(args[0])
		a = GetAttributes(args[0], env)
	}
	a = setProgLang(a)
	literal := te.getString(args[1]).String()
	literal := getString(args[1], env).GetValue()
	if a.HasDefault() {
		a = a.RemoveDefault()
		literal = visibleReplacer.Replace(literal)
	}
	res := sx.Nil().Cons(sx.MakeString(literal))
	if len(a) > 0 {
		res = res.Cons(te.transformAttribute(a))
		res = res.Cons(EvaluateAttrbute(a))
	}
	return res.Cons(sym)
}

func setProgLang(a attrs.Attributes) attrs.Attributes {
	if val, found := a.Get(""); found {
		a = a.AddClass("language-" + val).Remove("")
	}
	return a
}

func (te *TransformEnv) transformHTML(args []sx.Object) sx.Object {
	if s := te.getString(args[1]); s != "" && IsSafe(s.String()) {
		return sx.Nil().Cons(s).Cons(te.symNoEscape)
func (ev *Evaluator) evalHTML(args sx.Vector, env *Environment) sx.Object {
	if s := getString(ev.Eval(args[1], env), env); s.GetValue() != "" && IsSafe(s.GetValue()) {
		return sx.Nil().Cons(s).Cons(sxhtml.SymNoEscape)
	}
	return nil
}

func (te *TransformEnv) transformBLOB(description *sx.Pair, syntax, data sx.String) sx.Object {
	if data == "" {
func evalBLOB(description *sx.Pair, syntax, data sx.String) sx.Object {
	if data.GetValue() == "" {
		return sx.Nil()
	}
	switch syntax {
	switch syntax.GetValue() {
	case "":
		return sx.Nil()
	case api.ValueSyntaxSVG:
		return sx.Nil().Cons(sx.Nil().Cons(data).Cons(te.symNoEscape)).Cons(te.symP)
		return sx.Nil().Cons(sx.Nil().Cons(data).Cons(sxhtml.SymNoEscape)).Cons(SymP)
	default:
		imgAttr := sx.Nil().Cons(sx.Cons(te.Make("src"), sx.MakeString("data:image/"+syntax.String()+";base64,"+data.String())))
		imgAttr := sx.Nil().Cons(sx.Cons(SymAttrSrc, sx.MakeString("data:image/"+syntax.GetValue()+";base64,"+data.GetValue())))
		var sb strings.Builder
		te.flattenText(&sb, description)
		flattenText(&sb, description)
		if d := sb.String(); d != "" {
			imgAttr = imgAttr.Cons(sx.Cons(te.Make("alt"), sx.MakeString(d)))
			imgAttr = imgAttr.Cons(sx.Cons(symAttrAlt, sx.MakeString(d)))
		}
		return sx.Nil().Cons(sx.Nil().Cons(imgAttr.Cons(sxhtml.SymAttr)).Cons(SymIMG)).Cons(SymP)
	}
}

func flattenText(sb *strings.Builder, lst *sx.Pair) {
	for elem := lst; elem != nil; elem = elem.Tail() {
		switch obj := elem.Car().(type) {
		case sx.String:
			sb.WriteString(obj.GetValue())
		case *sx.Pair:
			flattenText(sb, obj)
		}
		return sx.Nil().Cons(sx.Nil().Cons(imgAttr.Cons(te.symAttr)).Cons(te.Make("img"))).Cons(te.symP)
	}
}

func (ev *Evaluator) evalList(args sx.Vector, env *Environment) sx.Object {
	return ev.evalSlice(args, env)
}
func nilFn(sx.Vector, *Environment) sx.Object { return sx.Nil() }
func (te *TransformEnv) flattenText(sb *strings.Builder, lst *sx.Pair) {
	for elem := lst; elem != nil; elem = elem.Tail() {

// Eval evaluates an object in an environment.
func (ev *Evaluator) Eval(obj sx.Object, env *Environment) sx.Object {
	if env.err != nil {
		switch obj := elem.Car().(type) {
		case sx.String:
		return sx.Nil()
			sb.WriteString(obj.String())
		case *sx.Pair:
			te.flattenText(sb, obj)
		}
	}
	if sx.IsNil(obj) {
		return obj
	}
	lst, isLst := sx.GetPair(obj)
	if !isLst {
		return obj
	}
	sym, found := sx.GetSymbol(lst.Car())
	if !found {
		env.err = fmt.Errorf("symbol expected, but got %T/%v", lst.Car(), lst.Car())
		return sx.Nil()
}

type transformFn func([]sx.Object) sx.Object

	}
	symVal := sym.GetValue()
	fn, found := ev.fns[symVal]
	if !found {
		env.err = fmt.Errorf("symbol %q not bound", sym)
		return sx.Nil()
	}
	var args sx.Vector
	for cdr := lst.Cdr(); !sx.IsNil(cdr); {
		pair, isPair := sx.GetPair(cdr)
		if !isPair {
			break
		}
func (te *TransformEnv) bind(name string, minArity int, fn transformFn) {
	te.astEnv.Bind(te.astSF.MustMake(name), sxeval.BuiltinA(func(args []sx.Object) (sx.Object, error) {
		if nArgs := len(args); nArgs < minArity {
			return sx.Nil(), fmt.Errorf("not enough arguments (%d) for form %v (%d)", nArgs, name, minArity)
		args = append(args, pair.Car())
		cdr = pair.Cdr()
	}
	if minArgs, hasMinArgs := ev.minArgs[symVal]; hasMinArgs {
		if minArgs > len(args) {
			env.err = fmt.Errorf("%v needs at least %d arguments, but got only %d", sym, minArgs, len(args))
			return sx.Nil()
		}
	}
		res := fn(args)
		return res, te.err
	result := fn(args, env)
	if env.err != nil {
		return sx.Nil()
	}
	return result
	}))
}

func (te *TransformEnv) Rebind(name string, fn func([]sx.Object, sxeval.Callable) sx.Object) {
	sym := te.astSF.MustMake(name)
	obj, found := te.astEnv.Lookup(sym)
func (ev *Evaluator) evalSlice(args sx.Vector, env *Environment) *sx.Pair {
	var result sx.ListBuilder
	for _, arg := range args {
		elem := ev.Eval(arg, env)
	if !found {
		panic(sym.String())
		result.Add(elem)
	}
	preFn, ok := sxeval.GetCallable(obj)
	if !ok {
	if env.err == nil {
		panic(sym.String())
		return result.List()
	}
	te.astEnv.Bind(sym, sxeval.BuiltinA(func(args []sx.Object) (sx.Object, error) {
		res := fn(args, preFn)
		return res, te.err
	return nil
	}))
}

// EvalPairList evaluates a list of lists.
func (ev *Evaluator) EvalPairList(pair *sx.Pair, env *Environment) *sx.Pair {
	var result sx.ListBuilder
	for node := pair; node != nil; node = node.Tail() {
		elem := ev.Eval(node.Car(), env)
		result.Add(elem)

	}
func (te *TransformEnv) Make(name string) *sx.Symbol { return te.tr.Make(name) }
func (te *TransformEnv) getSymbol(val sx.Object) *sx.Symbol {
	if te.err != nil {
		return nil
	}
	if sym, ok := sx.GetSymbol(val); ok {
		return sym
	}
	te.err = fmt.Errorf("%v/%T is not a symbol", val, val)
	return nil
	if env.err == nil {
		return result.List()
	}
	return nil
}

func (ev *Evaluator) evalLink(a attrs.Attributes, refValue sx.String, inline sx.Vector, env *Environment) sx.Object {
	result := ev.evalSlice(inline, env)
	if len(inline) == 0 {
		result = sx.Nil().Cons(refValue)
	}
	if ev.noLinks {
		return result.Cons(SymSPAN)
	}
	return result.Cons(EvaluateAttrbute(a)).Cons(SymA)
}

func getSymbol(obj sx.Object, env *Environment) *sx.Symbol {
	if env.err == nil {
		if sym, ok := sx.GetSymbol(obj); ok {
			return sym
		}
		env.err = fmt.Errorf("%v/%T is not a symbol", obj, obj)
	}
	return sx.MakeSymbol("???")
}
func (te *TransformEnv) getString(val sx.Object) sx.String {
	if te.err != nil {
		return ""
func getString(val sx.Object, env *Environment) sx.String {
	if env.err != nil {
		return sx.String{}
	}
	if s, ok := sx.GetString(val); ok {
		return s
	}
	te.err = fmt.Errorf("%v/%T is not a string", val, val)
	return ""
	env.err = fmt.Errorf("%v/%T is not a string", val, val)
	return sx.String{}
}
func (te *TransformEnv) getInt64(val sx.Object) int64 {
	if te.err != nil {
		return -1017
	}
	if num, ok := sx.GetNumber(val); ok {
		return int64(num.(sx.Int64))
	}
	te.err = fmt.Errorf("%v/%T is not a number", val, val)
	return -1017
}
func (te *TransformEnv) getList(val sx.Object) *sx.Pair {
	if te.err == nil {
func getList(val sx.Object, env *Environment) *sx.Pair {
	if env.err == nil {
		if res, isPair := sx.GetPair(val); isPair {
			return res
		}
		te.err = fmt.Errorf("%v/%T is not a list", val, val)
		env.err = fmt.Errorf("%v/%T is not a list", val, val)
	}
	return nil
}
func (te *TransformEnv) getAttributes(args sx.Object) attrs.Attributes {
	return sz.GetAttributes(te.getList(args))
}

func getInt64(val sx.Object, env *Environment) int64 {
	if env.err != nil {
		return -1017
	}
	if num, ok := sx.GetNumber(val); ok {
func (te *TransformEnv) transformLink(a attrs.Attributes, refValue sx.String, inline []sx.Object) sx.Object {
	result := sx.MakeList(inline...)
		return int64(num.(sx.Int64))
	if len(inline) == 0 {
		result = sx.Nil().Cons(refValue)
	}
	if te.tr.noLinks {
		return result.Cons(te.symSpan)
	}
	env.err = fmt.Errorf("%v/%T is not a number", val, val)
	return -1017
}
	return result.Cons(te.transformAttribute(a)).Cons(te.symA)
}

func (te *TransformEnv) transformAttribute(a attrs.Attributes) *sx.Pair {

// GetAttributes evaluates the given arg in the given environment and returns
// the contained attributes.
	return te.tr.TransformAttrbute(a)
}

func GetAttributes(arg sx.Object, env *Environment) attrs.Attributes {
func (te *TransformEnv) transformMeta(a attrs.Attributes) *sx.Pair {
	return te.tr.TransformMeta(a)
	return sz.GetAttributes(getList(arg, env))
}

var unsafeSnippets = []string{
	"<script", "</script",
	"<iframe", "</iframe",
}