//-----------------------------------------------------------------------------
// 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 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 := range 14 {
		ch := zid[i]
		if ch < '0' || '9' < ch {
			return false
		}
	}
	return true
}

// 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
	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 // 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.
//
// 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")

	ZidDeleteTemplate = ZettelID("00000000010405")
	ZidErrorTemplate  = ZettelID("00000000010700")

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

	// CSS-related zettel are in the range 20000..29999
	ZidBaseCSS = ZettelID("00000000020001")
	ZidUserCSS = ZettelID("00000000025001")


	// 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 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"

	MetaZettelmarkup = "Zettelmarkup"
)

// 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"

	KeySummary      = "summary"
	KeySuperior     = "superior"
	KeyURL          = "url"
	KeyUselessFiles = "useless-files"
	KeyUserID       = "user-id"
	KeyUserRole     = "user-role"
	KeyVisibility   = "visibility"
)

// Predefined metadata values.
const (
	ValueFalse             = "false"
	ValueTrue              = "true"
	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 (


	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"  // 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" // Plain zettel, no processing
	EncodingData  = "data"  // Plain zettel, metadata as S-Expression

)

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

	EncodingPlain: EncoderPlain,
	EncodingData:  EncoderData,

}
var mapEnumEncoding = map[EncodingEnum]string{}

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

	EncoderSHTML
	EncoderSz
	EncoderText
	EncoderZmk

	EncoderPlain
	EncoderData

)

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

// Supported search operator representations.
const (
	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 = "|" // 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    = "?"  // Does zettel have metadata with given key?
	ExistNotOperator = "!?" // True id zettel does not have metadata with given key.

	SearchOperatorNot        = "!"
	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 "t73f.de/r/webs/urlbuilder"






// URLBuilder should be used to create zettelstore URLs.
type URLBuilder struct {
	base   urlbuilder.URLBuilder
	prefix 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] == '/' {
		prefix = prefix[0 : len(prefix)-1]
	}

	result := URLBuilder{prefix: prefix}


	if key != '/' {
		result.base.AddPath(string([]byte{key}))


	}





	return &result
}


// Clone an URLBuilder.
func (ub *URLBuilder) Clone() *URLBuilder {




	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 {




	ub.base.AddPath(string(zid))
	return ub
}

// AppendPath adds a new path element.
func (ub *URLBuilder) AppendPath(p string) *URLBuilder {
	ub.base.AddPath(p)






	return ub
}

// AppendKVQuery adds a new key/value query parameter.
func (ub *URLBuilder) AppendKVQuery(key, value string) *URLBuilder {

	ub.base.AddQuery(key, value)
	return ub
}

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

		ub.base.AddQuery(QueryKeyQuery, value)
	}
	return ub
}

// ClearQuery removes all query parameters.
func (ub *URLBuilder) ClearQuery() *URLBuilder {

	ub.base.RemoveQueries()

	return ub
}

// SetFragment sets the fragment.
func (ub *URLBuilder) SetFragment(s string) *URLBuilder {

	ub.base.SetFragment(s)
	return ub
}

// String produces a string value.
func (ub *URLBuilder) String() string {

	return ub.prefix + ub.base.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"

	"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
}

// Add a value to an attribute key.
func (a Attributes) Add(key, value string) Attributes {
	if a == nil {
		return map[string]string{key: value}
	}
	values := a.Values(key)
	if !slices.Contains(values, value) {
		values = append(values, value)
		a[key] = strings.Join(values, " ")
	}
	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)
		}
	}



	return nil
}




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

// AddClass adds a value to the class attribute.
func (a Attributes) AddClass(class string) Attributes { return a.Add("class", class) }



// GetClasses returns the class values as a string slice

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"

	"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
	}{
		{"", "", 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 (

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

	"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 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()



	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 {
	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()
		}
		return nil, err
	}
	return resp, err
}

func (c *Client) buildAndExecuteRequest(
	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
	}



	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).GetValue()
	if len(token) < 4 {
		return fmt.Errorf("no valid token found: %q", token)
	}
	c.token = token
	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()))
	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)
	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))
	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)
	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)
}






















































































































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
}

























// UpdateZettel updates an existing zettel, specified by its zettel identifier.





















//



















// 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) 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))
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

// 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)

















	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)
	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)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		return statusToError(resp)
	}
	return nil
}

//-----------------------------------------------------------------------------
// 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"

	"t73f.de/r/zsc/api"

	"t73f.de/r/zsc/client"

)

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()



	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 t73f.de/r/zsc

go 1.23

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
)

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"

	"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"

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

// EncodeZettel transforms zettel data into a sx object.
func EncodeZettel(zettel api.ZettelData) sx.Object {

	return sx.MakeList(
		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).GetValue(),
		Content:  contentVals[1].(sx.String).GetValue(),
	}, nil
}

// EncodeMetaRights translates metadata/rights into a sx object.
func EncodeMetaRights(mr api.MetaRights) *sx.Pair {

	return sx.MakeList(
		sx.SymbolList,
		meta2sz(mr.Meta),
		sx.MakeList(sx.MakeSymbol("rights"), sx.Int64(int64(mr.Rights))),
	)
}

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(sx.MakeSymbol(k), sx.MakeString(m[k]))
		result.Add(val)
	}
	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)).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.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.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.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.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"

	"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 _, 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"

	"t73f.de/r/sx"

	"t73f.de/r/sxwebs/sxhtml"
	"t73f.de/r/zsc/api"
	"t73f.de/r/zsc/attrs"

	"t73f.de/r/zsc/sz"
	"t73f.de/r/zsc/text"
)

// Evaluator will transform a s-expression that encodes the zettel AST into an s-expression
// that represents HTML.
type Evaluator struct {


	headingOffset int64
	unique        string

	noLinks       bool // true iff output must not include links






	fns     map[string]EvalFn
	minArgs map[string]int



}

// NewEvaluator creates a new Evaluator object.
func NewEvaluator(headingOffset int) *Evaluator {
	ev := &Evaluator{





		headingOffset: int64(headingOffset),






		fns:     make(map[string]EvalFn, 128),
		minArgs: make(map[string]int, 128),
	}
	ev.bindMetadata()
	ev.bindBlocks()
	ev.bindInlines()
	return ev
}



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

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










// 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 && isValidName(key) {
			plist = plist.Cons(sx.Cons(sx.MakeSymbol(key), sx.MakeString(a[key])))
		}
	}
	if plist == nil {
		return nil
	}
	return plist.Cons(sxhtml.SymAttr)
}

// 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
		}


		noteHx, _ := ev.EvaluateList(env.endnotes[i].noteAST, env)
		env.endnotes[i].noteHx = noteHx


	}










	return pair, nil

}




// 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)
	}

	if err := env.err; err != nil {
		return nil, err
	}








	return result.List(), nil









}

// Endnotes returns a SHTML object with all collected endnotes.
func Endnotes(env *Environment) *sx.Pair {
	if env.err != nil || len(env.endnotes) == 0 {
		return nil
	}

	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)


		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(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)

		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())
	}

	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
}

// MakeEnvironment builds a new evaluation environment.
func MakeEnvironment(lang string) Environment {


	return Environment{
		err:          nil,


		langStack:    NewLangStack(lang),
		endnotes:     nil,


		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() }

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)






	evalMetaString := func(args sx.Vector, env *Environment) sx.Object {
		a := make(attrs.Attributes, 2).
			Set("name", getSymbol(args[0], env).GetValue()).
			Set("content", getString(args[1], env).GetValue())
		return ev.EvaluateMeta(a)
	}
	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 := getList(args[1], env); elem != nil; elem = elem.Tail() {
			sb.WriteByte(' ')
			sb.WriteString(getString(elem.Car(), env).GetValue())
		}
		s := sb.String()
		if len(s) > 0 {
			s = s[1:]
		}
		a := make(attrs.Attributes, 2).
			Set("name", getSymbol(args[0], env).GetValue()).
			Set("content", s)
		return ev.EvaluateMeta(a)
	}
	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 (ev *Evaluator) bindBlocks() {
	ev.bind(sz.SymBlock, 0, ev.evalList)
	ev.bind(sz.SymPara, 0, func(args sx.Vector, env *Environment) sx.Object {






		return ev.evalSlice(args, env).Cons(SymP)
	})
	ev.bind(sz.SymHeading, 5, func(args sx.Vector, env *Environment) sx.Object {
		nLevel := getInt64(args[0], env)
		if nLevel <= 0 {
			env.err = fmt.Errorf("%v is a negative heading level", nLevel)
			return sx.Nil()
		}
		level := strconv.FormatInt(nLevel+ev.headingOffset, 10)
		headingSymbol := sx.MakeSymbol("h" + level)

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

	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()
		}
		var items sx.ListBuilder
		items.Add(symDL)
		for pos := 0; pos < len(args); pos++ {
			term := ev.evalDescriptionTerm(getList(args[pos], env), env)
			items.Add(term.Cons(symDT))
			pos++
			if pos >= len(args) {
				break
			}
			ddBlock := getList(ev.Eval(args[pos], env), env)
			if ddBlock == nil {

				continue
			}
			for ddlst := ddBlock; ddlst != nil; ddlst = ddlst.Tail() {
				dditem := getList(ddlst.Car(), env)
				items.Add(dditem.Cons(symDD))
			}
		}
		return items.List()
	})

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

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

		var tbody sx.ListBuilder
		if len(args) > 1 {

			tbody.Add(symTBODY)
			for _, row := range args[1:] {
				tbody.Add(ev.evalTableRow(symTD, getList(row, env), env))
			}
		}

		table := sx.Nil()
		if !tbody.IsEmpty() {
			table = table.Cons(tbody.List())
		}
		if thead != nil {
			table = table.Cons(thead)
		}
		if table == nil {
			return sx.Nil()
		}
		return table.Cons(symTABLE)
	})
	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"))

	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))

	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 := getString(args[1], env); s.GetValue() != "" {

					return sx.Nil().Cons(s).Cons(sxhtml.SymBlockComment)
				}
			}
		}
		return nil
	})

	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))
	})
	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))
	})
	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.GetValue()))
		}
		return evalVerbatim(a, content)
	})
	ev.bind(sz.SymVerbatimZettel, 0, nilFn)
	ev.bind(sz.SymBLOB, 3, func(args sx.Vector, env *Environment) sx.Object {

		return evalBLOB(getList(args[0], env), getString(args[1], env), getString(args[2], env))
	})

	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 := 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(
				sxhtml.SymInlineComment,
				sx.MakeString("transclude"),
				refKind,
				sx.MakeString("->"),
				refValue,
			)
		}
		return ev.evalSlice(args, env)
	})
}

func (ev *Evaluator) makeListFn(sym *sx.Symbol) EvalFn {

	return func(args sx.Vector, env *Environment) sx.Object {
		var result sx.ListBuilder
		result.Add(sym)
		for _, elem := range args {
			item := sx.Nil().Cons(SymLI)
			if res, isPair := sx.GetPair(ev.Eval(elem, env)); isPair {
				item.ExtendBang(res)
			}
			result.Add(item)
		}
		return result.List()
	}
}

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
	}
	var row sx.ListBuilder
	row.Add(symTR)
	for pair := pairs; pair != nil; pair = pair.Tail() {
		row.Add(sx.Cons(sym, ev.Eval(pair.Car(), env)))
	}
	return row.List()
}

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(EvaluateAttrbute(attrs.Attributes{"class": align}))
		}
		return tdata
	}
}

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.Add(sym)
		if len(a) > 0 {
			result.Add(EvaluateAttrbute(a))
		}


		if region, isPair := sx.GetPair(args[1]); isPair {
			if evalRegion := ev.EvalPairList(region, env); evalRegion != nil {
				result.ExtendBang(evalRegion)
			}
		}
		if len(args) > 2 {
			if cite, _ := ev.EvaluateList(args[2:], env); cite != nil {
				result.Add(cite.Cons(symCITE))
			}
		}
		return result.List()
	}
}

func evalVerbatim(a attrs.Attributes, s sx.String) sx.Object {
	a = setProgLang(a)
	code := sx.Nil().Cons(s)
	if al := EvaluateAttrbute(a); al != nil {
		code = code.Cons(al)
	}
	code = code.Cons(symCODE)
	return sx.Nil().Cons(code).Cons(symPRE)
}

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) })






	ev.bind(sz.SymSoft, 0, func(sx.Vector, *Environment) sx.Object { return sx.MakeString(" ") })

	ev.bind(sz.SymHard, 0, func(sx.Vector, *Environment) sx.Object { return sx.Nil().Cons(symBR) })

	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 = ev.evalSlice(args[2:], env)
		}
		if inline == nil {
			inline = sx.Nil().Cons(ev.Eval(args[1], env))
		}
		return inline.Cons(SymSPAN)
	})
	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)
	}
	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)
	})
	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)
	})






	ev.bind(sz.SymLinkExternal, 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.Set("href", refValue.GetValue()).Add("rel", "external"), refValue, args[2:], env)
	})



	ev.bind(sz.SymEmbed, 3, func(args sx.Vector, env *Environment) sx.Object {
		ref := getList(args[1], env)





		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))
	})
	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,
		)
	})

	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 := getString(args[1], env); key.GetValue() != "" {
			if len(args) > 2 {
				result = ev.evalSlice(args[2:], env).Cons(sx.MakeString(", "))
			}
			result = result.Cons(key)
		}
		if len(a) > 0 {
			result = result.Cons(EvaluateAttrbute(a))
		}
		if result == nil {
			return nil
		}
		return result.Cons(SymSPAN)
	})
	ev.bind(sz.SymMark, 3, func(args sx.Vector, env *Environment) sx.Object {

		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(SymSPAN)
	})
	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 len(a) > 0 {
			if attrs := EvaluateAttrbute(a); attrs != nil {
				attrPlist = attrs.Tail()
			}
		}






		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)
	})

	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))

	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 := getString(ev.Eval(args[1], env), env); s.GetValue() != "" {
					return sx.Nil().Cons(s).Cons(sxhtml.SymInlineComment)
				}
			}
		}
		return sx.Nil()
	})
	ev.bind(sz.SymLiteralHTML, 2, ev.evalHTML)

	ev.bind(sz.SymLiteralInput, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalLiteral(args, nil, symKBD, env)
	})

	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)
	})

	ev.bind(sz.SymLiteralOutput, 2, func(args sx.Vector, env *Environment) sx.Object {
		return evalLiteral(args, nil, symSAMP, env)
	})
	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)
}

func (ev *Evaluator) makeFormatFn(sym *sx.Symbol) EvalFn {
	return func(args sx.Vector, env *Environment) sx.Object {

		a := GetAttributes(args[0], env)

		env.pushAttributes(a)

		defer env.popAttributes()
		if val, hasClass := a.Get(""); hasClass {
			a = a.Remove("").AddClass(val)
		}
		res := ev.evalSlice(args[1:], env)
		if len(a) > 0 {
			res = res.Cons(EvaluateAttrbute(a))
		}
		return res.Cons(sym)
	}
}

func (ev *Evaluator) evalQuote(args sx.Vector, env *Environment) sx.Object {
	a := GetAttributes(args[0], env)
	env.pushAttributes(a)
	defer env.popAttributes()




	if val, hasClass := a.Get(""); hasClass {
		a = a.Remove("").AddClass(val)
	}
	leftQ, rightQ, withNbsp := env.getQuotes()

	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))


		return res.Cons(SymSPAN)
	}
	return res.Cons(sxhtml.SymListSplice)
}

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

func evalLiteral(args sx.Vector, a attrs.Attributes, sym *sx.Symbol, env *Environment) sx.Object {
	if a == nil {
		a = GetAttributes(args[0], env)
	}
	a = setProgLang(a)
	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(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 (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 evalBLOB(description *sx.Pair, syntax, data sx.String) sx.Object {
	if data.GetValue() == "" {
		return sx.Nil()
	}
	switch syntax.GetValue() {
	case "":
		return sx.Nil()
	case api.ValueSyntaxSVG:
		return sx.Nil().Cons(sx.Nil().Cons(data).Cons(sxhtml.SymNoEscape)).Cons(SymP)
	default:
		imgAttr := sx.Nil().Cons(sx.Cons(SymAttrSrc, sx.MakeString("data:image/"+syntax.GetValue()+";base64,"+data.GetValue())))
		var sb strings.Builder
		flattenText(&sb, description)
		if d := sb.String(); 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)
		}

	}
}

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() }

// Eval evaluates an object in an environment.
func (ev *Evaluator) Eval(obj sx.Object, env *Environment) sx.Object {
	if env.err != nil {

		return sx.Nil()

	}
	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()
	}
	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
		}


		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()
		}
	}
	result := fn(args, env)
	if env.err != nil {
		return sx.Nil()
	}
	return result

}


func (ev *Evaluator) evalSlice(args sx.Vector, env *Environment) *sx.Pair {
	var result sx.ListBuilder
	for _, arg := range args {
		elem := ev.Eval(arg, env)


		result.Add(elem)
	}

	if env.err == nil {

		return result.List()
	}


	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)
	}


	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 getString(val sx.Object, env *Environment) sx.String {
	if env.err != nil {
		return sx.String{}
	}
	if s, ok := sx.GetString(val); ok {
		return s
	}
	env.err = fmt.Errorf("%v/%T is not a string", val, val)
	return sx.String{}
}










func getList(val sx.Object, env *Environment) *sx.Pair {
	if env.err == nil {
		if res, isPair := sx.GetPair(val); isPair {
			return res
		}
		env.err = fmt.Errorf("%v/%T is not a list", val, val)
	}
	return nil
}
func getInt64(val sx.Object, env *Environment) int64 {
	if env.err != nil {
		return -1017
	}
	if num, ok := sx.GetNumber(val); ok {

		return int64(num.(sx.Int64))


	}

	env.err = fmt.Errorf("%v/%T is not a number", val, val)
	return -1017
}


// GetAttributes evaluates the given arg in the given environment and returns
// the contained attributes.


func GetAttributes(arg sx.Object, env *Environment) attrs.Attributes {

	return sz.GetAttributes(getList(arg, env))
}

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

//-----------------------------------------------------------------------------
// 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 sz

import "t73f.de/r/sx"

// Various constants for Zettel data. They are technically variables.
var (

	// Symbols for Metanodes
	SymBlock  = sx.MakeSymbol("BLOCK")
	SymInline = sx.MakeSymbol("INLINE")

	SymMeta   = sx.MakeSymbol("META")









































	// Symbols for Zettel noMakede types.
	SymBLOB            = sx.MakeSymbol("BLOB")
	SymCell            = sx.MakeSymbol("CELL")
	SymCellCenter      = sx.MakeSymbol("CELL-CENTER")
	SymCellLeft        = sx.MakeSymbol("CELL-LEFT")
	SymCellRight       = sx.MakeSymbol("CELL-RIGHT")
	SymCite            = sx.MakeSymbol("CITE")
	SymDescription     = sx.MakeSymbol("DESCRIPTION")
	SymEmbed           = sx.MakeSymbol("EMBED")
	SymEmbedBLOB       = sx.MakeSymbol("EMBED-BLOB")
	SymEndnote         = sx.MakeSymbol("ENDNOTE")
	SymFormatEmph      = sx.MakeSymbol("FORMAT-EMPH")
	SymFormatDelete    = sx.MakeSymbol("FORMAT-DELETE")






	SymFormatInsert    = sx.MakeSymbol("FORMAT-INSERT")



	SymFormatMark      = sx.MakeSymbol("FORMAT-MARK")






	SymFormatQuote     = sx.MakeSymbol("FORMAT-QUOTE")


	SymFormatSpan      = sx.MakeSymbol("FORMAT-SPAN")
	SymFormatSub       = sx.MakeSymbol("FORMAT-SUB")
	SymFormatSuper     = sx.MakeSymbol("FORMAT-SUPER")
	SymFormatStrong    = sx.MakeSymbol("FORMAT-STRONG")



	SymHard            = sx.MakeSymbol("HARD")
	SymHeading         = sx.MakeSymbol("HEADING")



	SymLinkInvalid     = sx.MakeSymbol("LINK-INVALID")



	SymLinkZettel      = sx.MakeSymbol("LINK-ZETTEL")




	SymLinkSelf        = sx.MakeSymbol("LINK-SELF")
























	SymLinkFound       = sx.MakeSymbol("LINK-FOUND")
	SymLinkBroken      = sx.MakeSymbol("LINK-BROKEN")
	SymLinkHosted      = sx.MakeSymbol("LINK-HOSTED")
	SymLinkBased       = sx.MakeSymbol("LINK-BASED")
	SymLinkQuery       = sx.MakeSymbol("LINK-QUERY")
	SymLinkExternal    = sx.MakeSymbol("LINK-EXTERNAL")
	SymListOrdered     = sx.MakeSymbol("ORDERED")
	SymListUnordered   = sx.MakeSymbol("UNORDERED")
	SymListQuote       = sx.MakeSymbol("QUOTATION")
	SymLiteralProg     = sx.MakeSymbol("LITERAL-CODE")
	SymLiteralComment  = sx.MakeSymbol("LITERAL-COMMENT")
	SymLiteralHTML     = sx.MakeSymbol("LITERAL-HTML")
	SymLiteralInput    = sx.MakeSymbol("LITERAL-INPUT")
	SymLiteralMath     = sx.MakeSymbol("LITERAL-MATH")
	SymLiteralOutput   = sx.MakeSymbol("LITERAL-OUTPUT")
	SymLiteralZettel   = sx.MakeSymbol("LITERAL-ZETTEL")
	SymMark            = sx.MakeSymbol("MARK")
	SymPara            = sx.MakeSymbol("PARA")
	SymRegionBlock     = sx.MakeSymbol("REGION-BLOCK")
	SymRegionQuote     = sx.MakeSymbol("REGION-QUOTE")
	SymRegionVerse     = sx.MakeSymbol("REGION-VERSE")
	SymSoft            = sx.MakeSymbol("SOFT")


























	SymTable           = sx.MakeSymbol("TABLE")


	SymText            = sx.MakeSymbol("TEXT")
	SymThematic        = sx.MakeSymbol("THEMATIC")
	SymTransclude      = sx.MakeSymbol("TRANSCLUDE")



	SymUnknown         = sx.MakeSymbol("UNKNOWN-NODE")
	SymVerbatimComment = sx.MakeSymbol("VERBATIM-COMMENT")

	SymVerbatimEval    = sx.MakeSymbol("VERBATIM-EVAL")

	SymVerbatimHTML    = sx.MakeSymbol("VERBATIM-HTML")

	SymVerbatimMath    = sx.MakeSymbol("VERBATIM-MATH")





	SymVerbatimProg    = sx.MakeSymbol("VERBATIM-CODE")
	SymVerbatimZettel  = sx.MakeSymbol("VERBATIM-ZETTEL")












	// Constant symbols for reference states.







	SymRefStateInvalid  = sx.MakeSymbol("INVALID")
	SymRefStateZettel   = sx.MakeSymbol("ZETTEL")

	SymRefStateSelf     = sx.MakeSymbol("SELF")
	SymRefStateFound    = sx.MakeSymbol("FOUND")
	SymRefStateBroken   = sx.MakeSymbol("BROKEN")
	SymRefStateHosted   = sx.MakeSymbol("HOSTED")
	SymRefStateBased    = sx.MakeSymbol("BASED")
	SymRefStateQuery    = sx.MakeSymbol("QUERY")
	SymRefStateExternal = sx.MakeSymbol("EXTERNAL")








































	// Symbols for metadata types.
	SymTypeCredential   = sx.MakeSymbol("CREDENTIAL")
	SymTypeEmpty        = sx.MakeSymbol("EMPTY-STRING")
	SymTypeID           = sx.MakeSymbol("ZID")
	SymTypeIDSet        = sx.MakeSymbol("ZID-SET")
	SymTypeNumber       = sx.MakeSymbol("NUMBER")
	SymTypeString       = sx.MakeSymbol("STRING")
	SymTypeTagSet       = sx.MakeSymbol("TAG-SET")
	SymTypeTimestamp    = sx.MakeSymbol("TIMESTAMP")
	SymTypeURL          = sx.MakeSymbol("URL")
	SymTypeWord         = sx.MakeSymbol("WORD")

	SymTypeZettelmarkup = sx.MakeSymbol("ZETTELMARKUP")

)

//-----------------------------------------------------------------------------
// 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 sz

import (
	"t73f.de/r/sx"
	"t73f.de/r/zsc/api"
	"t73f.de/r/zsc/input"
)

// --- Contains some simple parsers

// ---- Syntax: none

// ParseNoneBlocks parses no block.
func ParseNoneBlocks(*input.Input) *sx.Pair { return nil }

// ParseNoneInlines skips to the end of line and parses no inline.
func ParseNoneInlines(inp *input.Input) *sx.Pair {
	inp.SkipToEOL()
	return nil
}

// ---- Some plain text syntaxes

// ParsePlainBlocks parses the block as plain text with the given syntax.
func ParsePlainBlocks(inp *input.Input, syntax string) *sx.Pair {
	var sym *sx.Symbol
	if syntax == api.ValueSyntaxHTML {
		sym = SymVerbatimHTML
	} else {
		sym = SymVerbatimProg
	}
	return sx.MakeList(
		sym,
		sx.MakeList(sx.Cons(sx.MakeString(""), sx.MakeString(syntax))),
		sx.MakeString(string(inp.ScanLineContent())),
	)
}

// ParsePlainInlines parses the inline as plain text with the given syntax.
func ParsePlainInlines(inp *input.Input, syntax string) *sx.Pair {
	var sym *sx.Symbol
	if syntax == api.ValueSyntaxHTML {
		sym = SymLiteralHTML
	} else {
		sym = SymLiteralProg
	}
	pos := inp.Pos
	inp.SkipToEOL()
	return sx.MakeList(
		sym,
		sx.MakeList(sx.Cons(sx.MakeString(""), sx.MakeString(syntax))),
		sx.MakeString(string(inp.Src[pos:inp.Pos])),
	)
}

//-----------------------------------------------------------------------------
// 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 sz_test

import (
	"testing"

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

func TestParseNone(t *testing.T) {
	if got := sz.ParseNoneBlocks(nil); got != nil {
		t.Error("GOTB", got)
	}

	inp := input.NewInput([]byte("1234\n6789"))
	if got := sz.ParseNoneInlines(inp); got != nil {
		t.Error("GOTI", got)
	}
	if got := inp.Pos; got != 4 {
		t.Errorf("input should be on position 4, but is %d", got)
	}
	if got := inp.Ch; got != '\n' {
		t.Errorf("input character should be 10, but is %d", got)
	}
}

func TestParsePlani(t *testing.T) {
	testcases := []struct {
		src        string
		syntax     string
		expBlocks  string
		expInlines string
	}{
		{"abc", "html",
			"(VERBATIM-HTML ((\"\" . \"html\")) \"abc\")",
			"(LITERAL-HTML ((\"\" . \"html\")) \"abc\")"},
		{"abc\ndef", "html",
			"(VERBATIM-HTML ((\"\" . \"html\")) \"abc\\ndef\")",
			"(LITERAL-HTML ((\"\" . \"html\")) \"abc\")"},
		{"abc", "text",
			"(VERBATIM-CODE ((\"\" . \"text\")) \"abc\")",
			"(LITERAL-CODE ((\"\" . \"text\")) \"abc\")"},
		{"abc\nDEF", "text",
			"(VERBATIM-CODE ((\"\" . \"text\")) \"abc\\nDEF\")",
			"(LITERAL-CODE ((\"\" . \"text\")) \"abc\")"},
	}
	for i, tc := range testcases {
		t.Run(tc.syntax+":"+tc.src, func(t *testing.T) {
			inp := input.NewInput([]byte(tc.src))
			if got := sz.ParsePlainBlocks(inp, tc.syntax).String(); tc.expBlocks != got {
				t.Errorf("%d: %q/%v\nexpected: %q\ngot     : %q", i, tc.src, tc.syntax, tc.expBlocks, got)
			}
			inp.SetPos(0)
			if got := sz.ParsePlainInlines(inp, tc.syntax).String(); tc.expInlines != got {
				t.Errorf("%d: %q/%v\nexpected: %q\ngot     : %q", i, tc.src, tc.syntax, tc.expInlines, got)
			}
		})
	}
}

//-----------------------------------------------------------------------------
// 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 sz contains zettel data handling as sx expressions.
package sz

import (
	"t73f.de/r/sx"
	"t73f.de/r/zsc/attrs"
)

// GetAttributes traverses a s-expression list and returns an attribute structure.
func GetAttributes(seq *sx.Pair) (result attrs.Attributes) {
	for elem := seq; elem != nil; elem = elem.Tail() {
		pair, isPair := sx.GetPair(elem.Car())
		if !isPair || pair == nil {
			continue
		}
		key := pair.Car()
		if !key.IsAtom() {
			continue
		}
		val := pair.Cdr()
		if tail, isTailPair := sx.GetPair(val); isTailPair {
			val = tail.Car()
		}
		if !val.IsAtom() {
			continue
		}
		result = result.Set(GoValue(key), GoValue(val))
	}
	return result
}

// GoValue returns the string value of the sx.Object suitable for Go processing.
func GoValue(obj sx.Object) string {
	switch o := obj.(type) {
	case sx.String:
		return o.GetValue()
	case *sx.Symbol:
		return o.GetValue()
	}
	return obj.String()
}

// GetMetaContent returns the metadata and the content of a sz encoded zettel.
func GetMetaContent(zettel sx.Object) (Meta, *sx.Pair) {
	if pair, isPair := sx.GetPair(zettel); isPair {
		m := pair.Car()
		if s := pair.Tail(); s != nil {
			if content, isContentPair := sx.GetPair(s.Car()); isContentPair {
				return MakeMeta(m), content
			}
		}
		return MakeMeta(m), nil
	}
	return nil, nil
}

// Meta map metadata keys to MetaValue.
type Meta map[string]MetaValue

// MetaValue is an extended metadata value:
//
//   - Type: the type assiciated with the metata key
//   - Key: the metadata key itself
//   - Value: the metadata value as an (sx-) object.
type MetaValue struct {
	Type  string
	Key   string
	Value sx.Object
}

// MakeMeta build a Meta based on a list of metadata objects.
func MakeMeta(obj sx.Object) Meta {
	if result := doMakeMeta(obj); len(result) > 0 {
		return result
	}
	return nil
}
func doMakeMeta(obj sx.Object) Meta {





	lst, isList := sx.GetPair(obj)
	if !isList || !lst.Car().IsEqual(SymMeta) {
		return nil
	}
	result := make(map[string]MetaValue)
	for node := lst.Tail(); node != nil; node = node.Tail() {
		if mv, found := makeMetaValue(node.Head()); found {
			result[mv.Key] = mv
		}

	}
	return result
}
func makeMetaValue(mnode *sx.Pair) (MetaValue, bool) {
	var result MetaValue




	typeSym, isSymbol := sx.GetSymbol(mnode.Car())
	if !isSymbol {




		return result, false
	}
	next := mnode.Tail()







	keySym, isSymbol := sx.GetSymbol(next.Car())
	if !isSymbol {
		return result, false
	}

	next = next.Tail()


	result.Type = typeSym.GetValue()
	result.Key = keySym.GetValue()
	result.Value = next.Car()
	return result, true
}

// GetString return the metadata string value associated with the given key.
func (m Meta) GetString(key string) string {
	if v, found := m[key]; found {
		return GoValue(v.Value)
	}
	return ""
}

// GetPair return the metadata value associated with the given key,
// as a list of objects.
func (m Meta) GetPair(key string) *sx.Pair {
	if mv, found := m[key]; found {
		if pair, isPair := sx.GetPair(mv.Value); isPair {
			return pair
		}
	}
	return nil
}

// MapRefStateToLinkEmbed maps a reference state symbol to a link symbol or to
// an embed symbol, depending on 'forLink'.
func MapRefStateToLinkEmbed(symRefState *sx.Symbol, forLink bool) *sx.Symbol {
	if !forLink {
		return SymEmbed
	}
	if sym, found := mapRefStateLink[symRefState]; found {
		return sym
	}
	return SymLinkInvalid
}

var mapRefStateLink = map[*sx.Symbol]*sx.Symbol{
	SymRefStateInvalid:  SymLinkInvalid,
	SymRefStateZettel:   SymLinkZettel,
	SymRefStateSelf:     SymLinkSelf,
	SymRefStateFound:    SymLinkFound,
	SymRefStateBroken:   SymLinkBroken,
	SymRefStateHosted:   SymLinkHosted,
	SymRefStateBased:    SymLinkBased,
	SymRefStateQuery:    SymLinkQuery,
	SymRefStateExternal: SymLinkExternal,
}

// IsBreakSym return true if the object is either a soft or a hard break symbol.
func IsBreakSym(obj sx.Object) bool {
	return SymSoft.IsEqual(obj) || SymHard.IsEqual(obj)
}

//-----------------------------------------------------------------------------
// 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 sz

import "t73f.de/r/sx"

// Visitor is walking the sx-based AST.
type Visitor interface {
	Visit(node *sx.Pair, env *sx.Pair) sx.Object
}

// Walk a sx-based AST through a Visitor.
func Walk(v Visitor, node *sx.Pair, env *sx.Pair) *sx.Pair {
	if node == nil {
		return nil
	}
	if result, isPair := sx.GetPair(v.Visit(node, env)); isPair {
		return result
	}

	if sym, isSymbol := sx.GetSymbol(node.Car()); isSymbol {
		if fn, found := mapChildrenWalk[sym]; found {
			return fn(v, node, env)
		}
		return node
	}
	panic(node)
}

var mapChildrenWalk map[*sx.Symbol]func(Visitor, *sx.Pair, *sx.Pair) *sx.Pair

func init() {
	mapChildrenWalk = map[*sx.Symbol]func(Visitor, *sx.Pair, *sx.Pair) *sx.Pair{
		SymBlock:         walkChildrenTail,
		SymPara:          walkChildrenTail,
		SymRegionBlock:   walkChildrenRegion,
		SymRegionQuote:   walkChildrenRegion,
		SymRegionVerse:   walkChildrenRegion,
		SymHeading:       walkChildrenHeading,
		SymListOrdered:   walkChildrenTail,
		SymListUnordered: walkChildrenTail,
		SymListQuote:     walkChildrenTail,
		SymDescription:   walkChildrenDescription,
		SymTable:         walkChildrenTable,

		SymInline:       walkChildrenTail,
		SymEndnote:      walkChildrenInlines3,
		SymMark:         walkChildrenMark,
		SymLinkBased:    walkChildrenInlines4,
		SymLinkBroken:   walkChildrenInlines4,
		SymLinkExternal: walkChildrenInlines4,
		SymLinkFound:    walkChildrenInlines4,
		SymLinkHosted:   walkChildrenInlines4,
		SymLinkInvalid:  walkChildrenInlines4,
		SymLinkQuery:    walkChildrenInlines4,
		SymLinkSelf:     walkChildrenInlines4,
		SymLinkZettel:   walkChildrenInlines4,
		SymEmbed:        walkChildrenEmbed,
		SymCite:         walkChildrenInlines4,
		SymFormatDelete: walkChildrenInlines3,
		SymFormatEmph:   walkChildrenInlines3,
		SymFormatInsert: walkChildrenInlines3,
		SymFormatMark:   walkChildrenInlines3,
		SymFormatQuote:  walkChildrenInlines3,
		SymFormatStrong: walkChildrenInlines3,
		SymFormatSpan:   walkChildrenInlines3,
		SymFormatSub:    walkChildrenInlines3,
		SymFormatSuper:  walkChildrenInlines3,
	}
}

func walkChildrenTail(v Visitor, node *sx.Pair, env *sx.Pair) *sx.Pair {
	hasNil := false
	for n := node.Tail(); n != nil; n = n.Tail() {
		obj := Walk(v, n.Head(), env)
		if sx.IsNil(obj) {
			hasNil = true
		}
		n.SetCar(obj)
	}
	if !hasNil {
		return node
	}
	for n := node; ; {
		next := n.Tail()
		if next == nil {
			break
		}
		if sx.IsNil(next.Car()) {
			n.SetCdr(next.Cdr())
			continue
		}
		n = next
	}
	return node
}

func walkChildrenList(v Visitor, lst *sx.Pair, env *sx.Pair) *sx.Pair {
	hasNil := false
	for n := lst; n != nil; n = n.Tail() {
		obj := Walk(v, n.Head(), env)
		if sx.IsNil(obj) {
			hasNil = true
		}
		n.SetCar(obj)
	}
	if !hasNil {
		return lst
	}
	var result sx.ListBuilder
	for n := lst; n != nil; n = n.Tail() {
		obj := n.Car()
		if !sx.IsNil(obj) {
			result.Add(obj)
		}
	}
	return result.List()
}

func walkChildrenRegion(v Visitor, node *sx.Pair, env *sx.Pair) *sx.Pair {
	// sym := node.Car()
	next := node.Tail()
	// attrs := next.Car()
	next = next.Tail()
	next.SetCar(walkChildrenList(v, next.Head(), env))
	next.SetCdr(walkChildrenList(v, next.Tail(), env))
	return node
}

func walkChildrenHeading(v Visitor, node *sx.Pair, env *sx.Pair) *sx.Pair {
	// sym := node.Car()
	next := node.Tail()
	// level := next.Car()
	next = next.Tail()
	// attrs := next.Car()
	next = next.Tail()
	// slug := next.Car()
	next = next.Tail()
	// fragment := next.Car()
	next.SetCdr(walkChildrenList(v, next.Tail(), env))
	return node
}

func walkChildrenDescription(v Visitor, dn *sx.Pair, env *sx.Pair) *sx.Pair {
	for n := dn.Tail(); n != nil; n = n.Tail() {
		n.SetCar(walkChildrenList(v, n.Head(), env))
		n = n.Tail()
		if n == nil {
			break
		}
		n.SetCar(Walk(v, n.Head(), env))
	}
	return dn
}

func walkChildrenTable(v Visitor, tn *sx.Pair, env *sx.Pair) *sx.Pair {
	for row := tn.Tail(); row != nil; row = row.Tail() {
		row.SetCar(walkChildrenList(v, row.Head(), env))
	}
	return tn
}

func walkChildrenMark(v Visitor, mn *sx.Pair, env *sx.Pair) *sx.Pair {
	// sym := mn.Car()
	next := mn.Tail()
	// mark := next.Car()
	next = next.Tail()
	// slug := next.Car()
	next = next.Tail()
	// fragment := next.Car()
	next.SetCdr(walkChildrenList(v, next.Tail(), env))
	return mn
}

func walkChildrenEmbed(v Visitor, en *sx.Pair, env *sx.Pair) *sx.Pair {
	// sym := en.Car()
	next := en.Tail()
	// attr := next.Car()
	next = next.Tail()
	// ref := next.Car()
	next = next.Tail()
	// syntax := next.Car()
	next = next.Tail()
	if next != nil {
		// text := next.Car()
		next.SetCar(Walk(v, next.Head(), env))
	}
	return en
}

func walkChildrenInlines4(v Visitor, ln *sx.Pair, env *sx.Pair) *sx.Pair {
	// sym := ln.Car()
	next := ln.Tail()
	// attrs := next.Car()
	next = next.Tail()
	// val3 := next.Car()
	next.SetCdr(walkChildrenList(v, next.Tail(), env))
	return ln
}

func walkChildrenInlines3(v Visitor, node *sx.Pair, env *sx.Pair) *sx.Pair {
	// sym := node.Car()
	next := node.Tail() // Attrs
	// attrs := next.Car()
	next.SetCdr(walkChildrenList(v, next.Tail(), env))
	return node
}

//-----------------------------------------------------------------------------
// 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 zmk

import (
	"fmt"

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

// parseBlock parses one block.
func (cp *zmkP) parseBlock(lastPara *sx.Pair) (res *sx.Pair, cont bool) {
	inp := cp.inp
	pos := inp.Pos
	if cp.nestingLevel <= maxNestingLevel {
		cp.nestingLevel++
		defer func() { cp.nestingLevel-- }()

		var bn *sx.Pair
		success := false

		switch inp.Ch {
		case input.EOS:
			return nil, false
		case '\n', '\r':
			inp.EatEOL()
			cp.cleanupListsAfterEOL()
			return nil, false
		case ':':
			bn, success = cp.parseColon()
		case '@', '`', runeModGrave, '%', '~', '$':
			cp.clearStacked()
			bn, success = cp.parseVerbatim()
		case '"', '<':
			cp.clearStacked()
			bn, success = cp.parseRegion()
		case '=':
			cp.clearStacked()
			bn, success = cp.parseHeading()
		case '-':
			cp.clearStacked()
			bn, success = cp.parseHRule()
		case '*', '#', '>':
			cp.lastRow = nil
			cp.descrl = nil
			bn, success = cp.parseNestedList()
		case ';':
			cp.lists = nil
			cp.lastRow = nil
			bn, success = cp.parseDefTerm()
		case ' ':
			cp.lastRow = nil
			bn, success = nil, cp.parseIndent()
		case '|':
			cp.lists = nil
			cp.descrl = nil
			bn, success = cp.parseRow(), true
		case '{':
			cp.clearStacked()
			bn, success = cp.parseTransclusion()
		}

		if success {
			return bn, false
		}
	}
	inp.SetPos(pos)
	cp.clearStacked()
	ins := cp.parsePara()
	if startsWithSpaceSoftBreak(ins) {
		ins = ins[2:]
	} else if lastPara != nil {
		lastPair := lastPara.LastPair()
		lastPair.ExtendBang(sx.MakeList(ins...))
		return nil, true
	}
	return sx.MakeList(ins...).Cons(sz.SymPara), false
}

func startsWithSpaceSoftBreak(ins sx.Vector) bool {
	if len(ins) < 2 {
		return false
	}
	pair0, isPair0 := sx.GetPair(ins[0])
	pair1, isPair1 := sx.GetPair(ins[0])
	if !isPair0 || !isPair1 {
		return false
	}
	if pair0.Car().IsEqual(sz.SymText) && sz.IsBreakSym(pair1.Car()) {
		if args := pair0.Tail(); args != nil {
			if val, isString := sx.GetString(args.Car()); isString {
				for _, ch := range val.GetValue() {
					if !input.IsSpace(ch) {
						return false
					}
				}
				return true
			}
		}
	}
	return false
}

var symSeparator = sx.MakeSymbol("sEpArAtOr")

func (cp *zmkP) cleanupListsAfterEOL() {
	for _, l := range cp.lists {
		l.LastPair().Head().LastPair().AppendBang(sx.Cons(symSeparator, nil))
	}
	if descrl := cp.descrl; descrl != nil {
		if lastPair, pos := lastPairPos(descrl); pos > 1 && pos%2 == 0 {
			lastPair.Head().LastPair().AppendBang(sx.Cons(symSeparator, nil))
		}
	}
}

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

// parsePara parses paragraphed inline material as a sx.Vector.
func (cp *zmkP) parsePara() (result sx.Vector) {
	for {
		in := cp.parseInline()
		if in == nil {
			return result
		}
		result = append(result, in)
		if sz.IsBreakSym(in.Car()) {
			ch := cp.inp.Ch
			switch ch {
			// Must contain all cases from above switch in parseBlock.
			case input.EOS, '\n', '\r', '@', '`', runeModGrave, '%', '~', '$', '"', '<', '=', '-', '*', '#', '>', ';', ':', ' ', '|', '{':
				return result
			}
		}
	}
}

// countDelim read from input until a non-delimiter is found and returns number of delimiter chars.
func (cp *zmkP) countDelim(delim rune) int {
	inp := cp.inp
	cnt := 0
	for inp.Ch == delim {
		cnt++
		inp.Next()
	}
	return cnt
}

// parseVerbatim parses a verbatim block.
func (cp *zmkP) parseVerbatim() (rn *sx.Pair, success bool) {
	inp := cp.inp
	fch := inp.Ch
	cnt := cp.countDelim(fch)
	if cnt < 3 {
		return nil, false
	}
	attrs := cp.parseBlockAttributes()
	inp.SkipToEOL()
	if inp.Ch == input.EOS {
		return nil, false
	}
	var sym *sx.Symbol
	switch fch {
	case '@':
		sym = sz.SymVerbatimZettel
	case '`', runeModGrave:
		sym = sz.SymVerbatimProg
	case '%':
		sym = sz.SymVerbatimComment
	case '~':
		sym = sz.SymVerbatimEval
	case '$':
		sym = sz.SymVerbatimMath
	default:
		panic(fmt.Sprintf("%q is not a verbatim char", fch))
	}
	content := make([]byte, 0, 512)
	for {
		inp.EatEOL()
		posL := inp.Pos
		switch inp.Ch {
		case fch:
			if cp.countDelim(fch) >= cnt {
				inp.SkipToEOL()
				rn = sx.MakeList(sym, attrs, sx.MakeString(string(content)))
				return rn, true
			}
			inp.SetPos(posL)
		case input.EOS:
			return nil, false
		}
		inp.SkipToEOL()
		if len(content) > 0 {
			content = append(content, '\n')
		}
		content = append(content, inp.Src[posL:inp.Pos]...)
	}
}

// parseRegion parses a block region.
func (cp *zmkP) parseRegion() (rn *sx.Pair, success bool) {
	inp := cp.inp
	fch := inp.Ch
	cnt := cp.countDelim(fch)
	if cnt < 3 {
		return nil, false
	}

	var sym *sx.Symbol
	oldInVerse := cp.inVerse
	defer func() { cp.inVerse = oldInVerse }()
	switch fch {
	case ':':
		sym = sz.SymRegionBlock
	case '<':
		sym = sz.SymRegionQuote
	case '"':
		sym = sz.SymRegionVerse
		cp.inVerse = true
	default:
		panic(fmt.Sprintf("%q is not a region char", fch))
	}
	attrs := cp.parseBlockAttributes()
	inp.SkipToEOL()
	if inp.Ch == input.EOS {
		return nil, false
	}
	var blocksBuilder sx.ListBuilder
	var lastPara *sx.Pair
	inp.EatEOL()
	for {
		posL := inp.Pos
		switch inp.Ch {
		case fch:
			if cp.countDelim(fch) >= cnt {
				ins := cp.parseRegionLastLine()
				rn = ins.Cons(blocksBuilder.List()).Cons(attrs).Cons(sym)
				return rn, true
			}
			inp.SetPos(posL)
		case input.EOS:
			return nil, false
		}
		bn, cont := cp.parseBlock(lastPara)
		if bn != nil {
			blocksBuilder.Add(bn)
		}
		if !cont {
			lastPara = bn
		}
	}
}

// parseRegionLastLine parses the last line of a region and returns its inline text.
func (cp *zmkP) parseRegionLastLine() *sx.Pair {
	inp := cp.inp
	cp.clearStacked() // remove any lists defined in the region
	inp.SkipSpace()
	var region sx.ListBuilder
	for {
		switch inp.Ch {
		case input.EOS, '\n', '\r':
			return region.List()
		}
		in := cp.parseInline()
		if in == nil {
			return region.List()
		}
		region.Add(in)
	}
}

// parseHeading parses a head line.
func (cp *zmkP) parseHeading() (hn *sx.Pair, success bool) {
	inp := cp.inp
	delims := cp.countDelim(inp.Ch)
	if delims < 3 {
		return nil, false
	}
	if inp.Ch != ' ' {
		return nil, false
	}
	inp.Next()
	inp.SkipSpace()
	if delims > 7 {
		delims = 7
	}
	level := int64(delims - 2)
	var attrs *sx.Pair
	var text sx.ListBuilder
	for {
		if input.IsEOLEOS(inp.Ch) {
			return createHeading(level, attrs, text.List()), true
		}
		in := cp.parseInline()
		if in == nil {
			return createHeading(level, attrs, text.List()), true
		}
		text.Add(in)
		if inp.Ch == '{' && inp.Peek() != '{' {
			attrs = cp.parseBlockAttributes()
			inp.SkipToEOL()
			return createHeading(level, attrs, text.List()), true
		}
	}
}
func createHeading(level int64, attrs, text *sx.Pair) *sx.Pair {
	return text.
		Cons(sx.MakeString("")). // Fragment
		Cons(sx.MakeString("")). // Slug
		Cons(attrs).
		Cons(sx.Int64(level)).
		Cons(sz.SymHeading)
}

// parseHRule parses a horizontal rule.
func (cp *zmkP) parseHRule() (hn *sx.Pair, success bool) {
	inp := cp.inp
	if cp.countDelim(inp.Ch) < 3 {
		return nil, false
	}

	attrs := cp.parseBlockAttributes()
	inp.SkipToEOL()
	return sx.MakeList(sz.SymThematic, attrs), true
}

// parseNestedList parses a list.
func (cp *zmkP) parseNestedList() (res *sx.Pair, success bool) {
	kinds := cp.parseNestedListKinds()
	if len(kinds) == 0 {
		return nil, false
	}
	inp := cp.inp
	inp.SkipSpace()
	if !kinds[len(kinds)-1].IsEqual(sz.SymListQuote) && input.IsEOLEOS(inp.Ch) {
		return nil, false
	}

	if len(kinds) < len(cp.lists) {
		cp.lists = cp.lists[:len(kinds)]
	}
	ln, newLnCount := cp.buildNestedList(kinds)
	pv := cp.parseLinePara()
	bn := sx.Cons(sz.SymBlock, nil)
	if len(pv) != 0 {
		bn.AppendBang(pv.MakeList().Cons(sz.SymPara))
	}
	lastItemPair := ln.LastPair()
	lastItemPair.AppendBang(bn)
	return cp.cleanupParsedNestedList(newLnCount)
}

func (cp *zmkP) parseNestedListKinds() []*sx.Symbol {
	inp := cp.inp
	result := make([]*sx.Symbol, 0, 8)
	for {
		var sym *sx.Symbol
		switch inp.Ch {
		case '*':
			sym = sz.SymListUnordered
		case '#':
			sym = sz.SymListOrdered
		case '>':
			sym = sz.SymListQuote
		default:
			panic(fmt.Sprintf("%q is not a region char", inp.Ch))
		}
		result = append(result, sym)
		switch inp.Next() {
		case '*', '#', '>':
		case ' ', input.EOS, '\n', '\r':
			return result
		default:
			return nil
		}
	}
}

func (cp *zmkP) buildNestedList(kinds []*sx.Symbol) (ln *sx.Pair, newLnCount int) {
	for i, kind := range kinds {
		if i < len(cp.lists) {
			if !cp.lists[i].Car().IsEqual(kind) {
				ln = sx.Cons(kind, nil)
				newLnCount++
				cp.lists[i] = ln
				cp.lists = cp.lists[:i+1]
			} else {
				ln = cp.lists[i]
			}
		} else {
			ln = sx.Cons(kind, nil)
			newLnCount++
			cp.lists = append(cp.lists, ln)
		}
	}
	return ln, newLnCount
}

func (cp *zmkP) cleanupParsedNestedList(newLnCount int) (res *sx.Pair, success bool) {
	childPos := len(cp.lists) - 1
	parentPos := childPos - 1
	for i := 0; i < newLnCount; i++ {
		if parentPos < 0 {
			return cp.lists[0], true
		}
		parentLn := cp.lists[parentPos]
		childLn := cp.lists[childPos]
		if firstParent := parentLn.Tail(); firstParent != nil {
			// Add list to last item of the parent list
			lastParent := firstParent.LastPair()
			lastParent.Head().LastPair().AppendBang(childLn)
		} else {
			// Set list to first child of parent.
			childBlock := sx.MakeList(sz.SymBlock, cp.lists[childPos])
			parentLn.LastPair().AppendBang(childBlock)
		}
		childPos--
		parentPos--
	}
	return nil, true
}

// parseDefTerm parses a term of a definition list.
func (cp *zmkP) parseDefTerm() (res *sx.Pair, success bool) {
	inp := cp.inp
	if inp.Next() != ' ' {
		return nil, false
	}
	inp.Next()
	inp.SkipSpace()
	descrl := cp.descrl
	if descrl == nil {
		descrl = sx.Cons(sz.SymDescription, nil)
		cp.descrl = descrl
		res = descrl
	}
	lastPair, pos := lastPairPos(descrl)
	for {
		in := cp.parseInline()
		if in == nil {
			if pos%2 == 0 {
				// lastPair is either the empty description list or the last block of definitions
				return nil, false
			}
			// lastPair is the definition term
			return res, true
		}
		if pos%2 == 0 {
			// lastPair is either the empty description list or the last block of definitions
			lastPair = lastPair.AppendBang(sx.Cons(in, nil))
			pos++
		} else {
			// lastPair is the term part and we need to append the inline list just read
			lastPair.Head().LastPair().AppendBang(in)
		}
		if sz.IsBreakSym(in.Car()) {
			return res, true
		}
	}
}

// parseDefDescr parses a description of a definition list.
func (cp *zmkP) parseDefDescr() (res *sx.Pair, success bool) {
	inp := cp.inp
	if inp.Next() != ' ' {
		return nil, false
	}
	inp.Next()
	inp.SkipSpace()
	descrl := cp.descrl
	lastPair, pos := lastPairPos(descrl)
	if descrl == nil || pos <= 0 {
		// No term given
		return nil, false
	}

	pn := cp.parseLinePara()
	if len(pn) == 0 {
		return nil, false
	}

	newDef := sx.MakeList(sz.SymBlock, pn.MakeList().Cons(sz.SymPara))
	if pos%2 == 1 {
		// Just a term, but no definitions
		lastPair.AppendBang(sx.MakeList(sz.SymBlock, newDef))
	} else {
		// lastPara points a the last definition
		lastPair.Head().LastPair().AppendBang(newDef)
	}
	return nil, true
}

func lastPairPos(p *sx.Pair) (*sx.Pair, int) {
	cnt := 0
	for node := p; node != nil; {
		next := node.Tail()
		if next == nil {
			return node, cnt
		}
		node = next
		cnt++
	}
	return nil, -1
}

// parseIndent parses initial spaces to continue a list.
func (cp *zmkP) parseIndent() bool {
	inp := cp.inp
	cnt := 0
	for {
		if inp.Next() != ' ' {
			break
		}
		cnt++
	}
	if cp.lists != nil {
		return cp.parseIndentForList(cnt)
	}
	if cp.descrl != nil {
		return cp.parseIndentForDescription(cnt)
	}
	return false
}

func (cp *zmkP) parseIndentForList(cnt int) bool {
	if len(cp.lists) < cnt {
		cnt = len(cp.lists)
	}
	cp.lists = cp.lists[:cnt]
	if cnt == 0 {
		return false
	}
	pv := cp.parseLinePara()
	if len(pv) == 0 {
		return false
	}
	ln := cp.lists[cnt-1]
	lbn := ln.LastPair().Head()
	lpn := lbn.LastPair().Head()
	pvList := pv.MakeList()
	if lpn.Car().IsEqual(sz.SymPara) {
		lpn.LastPair().SetCdr(pvList)
	} else {
		lbn.LastPair().AppendBang(pvList.Cons(sz.SymPara))
	}
	return true
}

func (cp *zmkP) parseIndentForDescription(cnt int) bool {
	descrl := cp.descrl
	lastPair, pos := lastPairPos(descrl)
	if cnt < 1 || pos < 1 {
		return false
	}
	if pos%2 == 1 {
		// Continuation of a definition term
		for {
			in := cp.parseInline()
			if in == nil {
				return true
			}
			lastPair.Head().LastPair().AppendBang(in)
			if sz.IsBreakSym(in.Car()) {
				return true
			}
		}
	}

	// Continuation of a definition description
	pn := cp.parseLinePara()
	if len(pn) == 0 {
		return false
	}
	bn := lastPair.Head()
	para := bn.LastPair().Head().LastPair().Head()
	pnList := pn.MakeList()
	if para.Car().IsEqual(sz.SymPara) {
		para.LastPair().SetCdr(pnList)
	} else {
		bn.LastPair().AppendBang(pnList.Cons(sz.SymPara))
	}
	return true
}

// parseLinePara parses one paragraph of inline material.
func (cp *zmkP) parseLinePara() sx.Vector {
	var ins sx.Vector
	for {
		in := cp.parseInline()
		if in == nil {
			return ins
		}
		ins = append(ins, in)
		if sz.IsBreakSym(in.Car()) {
			return ins
		}
	}
}

// parseRow parse one table row.
func (cp *zmkP) parseRow() *sx.Pair {
	inp := cp.inp
	if inp.Peek() == '%' {
		inp.SkipToEOL()
		return nil
	}
	//var row, curr *sx.Pair
	var row sx.ListBuilder
	for {
		inp.Next()
		cell := cp.parseCell()
		if cell != nil {
			row.Add(cell)
		}
		switch inp.Ch {
		case '\n', '\r':
			inp.EatEOL()
			fallthrough
		case input.EOS:
			// add to table
			if cp.lastRow == nil {
				if row.IsEmpty() {
					return nil
				}
				cp.lastRow = sx.Cons(row.List(), nil)
				return cp.lastRow.Cons(nil).Cons(sz.SymTable)
			}
			cp.lastRow = cp.lastRow.AppendBang(row.List())
			return nil
		}
		// inp.Ch must be '|'
	}
}

// parseCell parses one single cell of a table row.
func (cp *zmkP) parseCell() *sx.Pair {
	inp := cp.inp
	var cell sx.ListBuilder
	for {
		if input.IsEOLEOS(inp.Ch) {
			if cell.IsEmpty() {
				return nil
			}
			return cell.List().Cons(sz.SymCell)
		}
		if inp.Ch == '|' {
			return cell.List().Cons(sz.SymCell)
		}

		in := cp.parseInline()
		cell.Add(in)
	}
}

// parseTransclusion parses '{' '{' '{' ZID '}' '}' '}'
func (cp *zmkP) parseTransclusion() (*sx.Pair, bool) {
	if cp.countDelim('{') != 3 {
		return nil, false
	}
	inp := cp.inp
	posA, posE := inp.Pos, 0

loop:

	for {
		switch inp.Ch {
		case input.EOS:
			return nil, false
		case '\n', '\r', ' ', '\t':
			if !hasQueryPrefix(inp.Src[posA:]) {
				return nil, false
			}
		case '\\':
			switch inp.Next() {
			case input.EOS, '\n', '\r':
				return nil, false
			}
		case '}':
			posE = inp.Pos
			if posA >= posE {
				return nil, false
			}
			if inp.Next() != '}' {
				continue
			}
			if inp.Next() != '}' {
				continue
			}
			break loop
		}
		inp.Next()
	}
	inp.Next() // consume last '}'
	a := cp.parseBlockAttributes()
	inp.SkipToEOL()
	refText := string(inp.Src[posA:posE])
	ref := ParseReference(refText)
	return sx.MakeList(sz.SymTransclude, a, ref), true
}