// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package ofdgo

import (
	"archive/zip"
	"bytes"
	"encoding/hex"
	"encoding/xml"
	"fmt"
	"io"
	"maps"
	"path"
	"reflect"
	"slices"
	"strconv"
	"strings"
	"time"
)

const ofdNamespace = "http://www.ofdspec.org/2016"

// editorProgress 保存准备阶段的进度检查点，内存预览使用nil
type editorProgress func(stage string, completed, total int) error

// report 回报进度并原样传递调用方停止原因
// 入参: stage 阶段, completed 已处理项, total 总项数
// 返回: error 调用方停止原因
func (progress editorProgress) report(stage string, completed, total int) error {
	if progress != nil {
		return progress(stage, completed, total)
	}
	return nil
}

// WriteTo 逐个条目写出OFD，不关闭调用方输出流，出错时应丢弃本次输出
// 新增资源仅写入实际引用的部分，静态TrueType轮廓字体按实际文字生成子集
// 原有字体在全包引用可确定时保留字形编号裁剪；编辑资源、复杂字体及无法确定的引用保持原样
// 重开子集文档后输入未包含的文字，需要通过AddFont注册完整字体并替换原字体引用
// 入参: writer 输出流
// 返回: int64 已写入字节数, error 错误信息
func (e *Editor) WriteTo(writer io.Writer) (int64, error) {
	if e.encryption != nil {
		return e.writeEncrypted(writer)
	}
	return e.writePlaintext(writer)
}

// writePlaintext 写出未加密包，供显式明文输出与加密封装共用
// 入参: writer 输出流
// 返回: int64 写入字节数, error 错误信息
func (e *Editor) writePlaintext(writer io.Writer) (int64, error) {
	if err := e.validate(); err != nil {
		return 0, err
	}
	progress := editorProgress(e.OnWriteProgress)
	fonts, err := e.subsetFonts(progress)
	if err != nil {
		return 0, err
	}
	if e.source != nil {
		return e.writeSource(writer, fonts, progress)
	}
	if err := progress.report("write", 0, 0); err != nil {
		return 0, err
	}
	output := &ofdCountingWriter{writer: writer}
	archive := zip.NewWriter(output)
	err = e.writeParts(func(name string, data []byte, compressed bool) error {
		if subset, ok := fonts[name]; ok {
			data = subset
		}
		method := uint16(zip.Deflate)
		if compressed {
			method = zip.Store
		}
		entry, err := archive.CreateHeader(&zip.FileHeader{Name: name, Method: method})
		if err != nil {
			return err
		}
		_, err = entry.Write(data)
		return err
	}, progress)
	if err == nil {
		err = archive.Close()
	}
	return output.count, err
}

// WritePagesTo 按指定顺序将页面另存为独立OFD，不修改当前文档或撤销记录
// 保留描述信息并生成新文档标识，迁移相关资源、目录、注释和签章外观，移除指向未选页面的跳转
// 快照只准备所选页面，关联引用由页面导入流程统一筛选
// 签名凭据不代表另存文件验签有效；进度与取消复用OnWriteProgress，另含snapshot、ids和commit阶段
// 入参: writer 输出流, indexes 从0开始的页面索引，不可重复或为空
// 返回: int64 已写入字节数, error 错误信息
func (e *Editor) WritePagesTo(writer io.Writer, indexes []int) (int64, error) {
	if len(indexes) == 0 {
		return 0, fmt.Errorf("no pages selected")
	}
	if err := e.validatePageIndexes(indexes); err != nil {
		return 0, err
	}
	progress := editorProgress(e.OnWriteProgress)
	if err := progress.report("snapshot", 0, 0); err != nil {
		return 0, err
	}
	snapshot := *e
	snapshot.pages = make([]PageContent, len(indexes))
	if e.source != nil {
		source := *e.source
		source.pages = make(map[string]*editorSourcePage, len(indexes))
		source.annotationPages = nil
		for _, index := range indexes {
			id := e.pages[index].ID
			if page := e.source.pages[id]; page != nil {
				source.pages[id] = page
			}
		}
		snapshot.source = &source
	}
	positions := make([]int, len(indexes))
	for i, index := range indexes {
		snapshot.pages[i] = e.pages[index]
		positions[i] = i
	}
	reader, err := snapshot.reader(progress)
	if err != nil {
		return 0, err
	}
	defer reader.Close()
	selected := NewEditor()
	selected.encryption = e.encryption
	id := selected.Info.DocID
	selected.Info = cloneEditorData(e.Info)
	selected.Info.DocID = id
	selected.OnWriteProgress = e.OnWriteProgress
	if _, err := selected.ImportPagesWithOptions(reader, positions, 0, PageImportOptions{Outlines: true, OnProgress: e.OnWriteProgress}); err != nil {
		return 0, err
	}
	return selected.WriteTo(writer)
}

// Reader 获取当前文档的独立内存快照，不进行ZIP压缩，后续修改不影响已有快照
// 返回的Reader可用于现有渲染、搜索和导出接口，新增资源仅包含实际引用的部分，二进制数据内部共享只读
// 返回: *Reader 阅读器, error 错误信息
func (e *Editor) Reader() (*Reader, error) {
	return e.reader(nil)
}

// reader 生成内存快照，保存时复用准备进度，预览时不触发回调
// 入参: progress 准备进度回调
// 返回: *Reader 阅读器, error 错误信息
func (e *Editor) reader(progress editorProgress) (*Reader, error) {
	if err := e.validate(); err != nil {
		return nil, err
	}
	if e.source != nil {
		return e.sourceReader(progress)
	}
	r := &Reader{files: make(map[string][]byte), encryption: e.encryption}
	if err := e.writeParts(func(name string, data []byte, _ bool) error {
		r.files[name] = data
		return nil
	}, progress); err != nil {
		return nil, err
	}
	if err := r.initRoot(); err != nil {
		return nil, err
	}
	if _, err := r.Doc(); err != nil {
		return nil, err
	}
	for i, page := range r.doc.Pages.Page {
		r.pageHeaderCache[r.ResPath(page.BaseLoc)] = PageContent{Area: PageArea{PhysicalBox: e.pages[i].Area.PhysicalBox}}
	}
	return r, nil
}

// validate 校验文档保存条件
// 返回: error 错误信息
func (e *Editor) validate() error {
	if len(e.pages) == 0 {
		return fmt.Errorf("document must contain at least one page")
	}
	if e.source == nil || e.Info.DocID != e.source.info.DocID {
		if data, err := hex.DecodeString(e.Info.DocID); err != nil || len(data) != 16 {
			return fmt.Errorf("DocID must contain 32 hexadecimal characters")
		}
	}
	for i, date := range []string{e.Info.CreationDate, e.Info.ModDate} {
		if e.source != nil && date == []string{e.source.info.CreationDate, e.source.info.ModDate}[i] {
			continue
		}
		if date != "" {
			if _, err := time.Parse("2006-01-02", date); err != nil {
				return fmt.Errorf("invalid document date: %w", err)
			}
		}
	}
	return nil
}

// writeParts 生成根节点、文档、资源索引、页面及二进制资源
// 入参: write 条目写入方法, progress 保存进度回调，预览时为nil
// 返回: error 错误信息
func (e *Editor) writeParts(write func(string, []byte, bool) error, progress editorProgress) error {
	if len(e.removedPages) != 0 {
		output := write
		write = func(name string, data []byte, binary bool) error {
			if !binary && strings.EqualFold(path.Ext(name), ".xml") {
				var err error
				data, err = pruneCreatedPageReferences(data, e.removedPages)
				if err != nil {
					return err
				}
			}
			return output(name, data, binary)
		}
	}
	fonts, images, spaces, definitions := e.usedResources()
	writeXML := func(name string, encode func(*ofdXML)) error {
		data, err := encodeOFDXML(encode)
		if err != nil {
			return err
		}
		if name == "Doc_0/Document.xml" {
			data, err = e.withOutlines(data)
			if err != nil {
				return err
			}
		}
		return write(name, data, false)
	}
	if err := writeXML("OFD.xml", func(x *ofdXML) {
		x.root("OFD", ofdAttrs{{Name: xml.Name{Local: "Version"}, Value: "1.0"}, {Name: xml.Name{Local: "DocType"}, Value: "OFD"}})
		x.start("DocBody", nil)
		x.start("DocInfo", nil)
		for _, field := range [][2]string{
			{"DocID", e.Info.DocID}, {"Title", e.Info.Title}, {"Author", e.Info.Author},
			{"Subject", e.Info.Subject}, {"Abstract", e.Info.Abstract},
			{"CreationDate", e.Info.CreationDate}, {"ModDate", e.Info.ModDate},
			{"Creator", "xiaoqidun/ofdgo"},
		} {
			if field[1] != "" {
				x.text(field[0], field[1])
			}
		}
		if e.Info.CustomDatas != nil && len(e.Info.CustomDatas.CustomData) != 0 {
			x.start("CustomDatas", nil)
			for _, item := range e.Info.CustomDatas.CustomData {
				attrs := ofdAttrs{{Name: xml.Name{Local: "Name"}, Value: item.Name}}
				x.start("CustomData", attrs)
				x.token(xml.CharData(item.Value))
				x.end("CustomData")
			}
			x.end("CustomDatas")
		}
		x.end("DocInfo")
		x.text("DocRoot", "Doc_0/Document.xml")
		x.end("DocBody")
		x.end("OFD")
	}); err != nil {
		return err
	}
	if err := writeXML("Doc_0/Document.xml", func(x *ofdXML) {
		x.root("Document", nil)
		x.start("CommonData", nil)
		x.text("MaxUnitID", strconv.Itoa(e.maxID))
		x.start("PageArea", nil)
		x.text("PhysicalBox", e.pages[0].Area.PhysicalBox)
		x.end("PageArea")
		if len(fonts)+len(images)+len(spaces) != 0 {
			x.text("DocumentRes", "DocumentRes.xml")
		}
		for _, name := range definitions {
			x.text("DocumentRes", "/"+name)
		}
		x.end("CommonData")
		x.start("Pages", nil)
		for _, page := range e.pages {
			var attrs ofdAttrs
			attrs.add("ID", page.ID)
			attrs.add("BaseLoc", packagePagePath("", page.ID))
			x.start("Page", attrs)
			x.end("Page")
		}
		x.end("Pages")
		x.end("Document")
	}); err != nil {
		return err
	}
	if len(fonts)+len(images)+len(spaces) != 0 {
		if err := writeXML("Doc_0/DocumentRes.xml", func(x *ofdXML) { x.resources(fonts, images, spaces) }); err != nil {
			return err
		}
	}
	for i, page := range e.pages {
		if err := progress.report("pages", i, len(e.pages)); err != nil {
			return err
		}
		name := packagePagePath(e.packageDirectory(), page.ID)
		if len(e.origins) == 0 {
			if err := writeXML(name, func(x *ofdXML) { x.page(page) }); err != nil {
				return err
			}
		} else {
			data, err := e.sourceNewPageXML(page)
			if err != nil {
				return err
			}
			if err := write(name, data, false); err != nil {
				return err
			}
		}
	}
	if err := progress.report("pages", len(e.pages), len(e.pages)); err != nil {
		return err
	}
	for _, resources := range [][]editorResource{fonts, images} {
		for _, resource := range resources {
			if err := write(resource.name, resource.data, resource.image != nil); err != nil {
				return err
			}
		}
	}
	for _, resource := range e.resources {
		if resource.definition() != "" && slices.Contains(definitions, resource.name) {
			if err := write(resource.name, resource.data, false); err != nil {
				return err
			}
		}
	}
	return nil
}

// usedResources 筛选当前引用的新增资源及需要跨页复用的原资源文件，不修改资源池
// 返回: []editorResource 新增字体, []editorResource 新增图片, []ColorSpace 新增颜色空间, []string 原资源文件
func (e *Editor) usedResources() (fonts, images []editorResource, spaces []ColorSpace, sourceFiles []string) {
	used := make(map[string]bool)
	promoted := make(map[string]bool)
	files := make(map[string]bool)
	if e.source != nil {
		for _, name := range e.annotationFiles() {
			data, changed := e.source.reader.files[name]
			if !changed {
				continue
			}
			refs := editorResourceRefs{ids: used, files: make(map[string]bool)}
			if _, safe := refs.scan(bytes.NewReader(data), name); !safe {
				for _, resource := range e.resources {
					if resource.font != nil {
						used[resource.font.ID] = true
					}
					if resource.image != nil {
						used[resource.image.ID] = true
					}
					if resource.space != nil {
						used[resource.space.ID] = true
					}
					used[resource.definition()] = true
				}
			}
		}
		maps.Copy(promoted, used)
	}
	for _, page := range e.pages {
		var original map[string]GraphicObject
		if e.source != nil {
			original = make(map[string]GraphicObject)
			if source := e.source.pages[page.ID]; source != nil && source.original != nil {
				for _, layer := range source.original.Content.Layer {
					for _, object := range layer.Objects {
						original[editorObjectID(object)] = object
					}
				}
			}
		}
		for _, layer := range page.Content.Layer {
			for _, object := range layer.Objects {
				before, exists := original[editorObjectID(object)]
				collectObjectReferences(object, used)
				if e.source != nil && (!exists || !reflect.DeepEqual(before, object)) {
					collectObjectReferences(object, promoted)
				}
				if origin := e.objectOrigin(editorObjectID(object)); origin != nil && origin.page != nil && (!exists || before.Type != object.Type || !reflect.DeepEqual(before.CompositeGraphicUnit, object.CompositeGraphicUnit)) {
					for _, name := range origin.page.original.PageRes {
						files[e.source.reader.ResPath(resolveResourcePath(origin.page.ref.BaseLoc, "", name))] = true
					}
				}
			}
		}
	}
	for i := len(e.resources) - 1; i >= 0; i-- {
		resource := e.resources[i]
		if resource.definition() != "" && used[resource.definition()] {
			for _, id := range resource.references {
				used[id] = true
				if e.source != nil {
					promoted[id] = true
				}
			}
		}
	}
	for _, resource := range e.resources {
		if resource.definition() != "" && used[resource.definition()] {
			files[resource.name] = true
		}
		if resource.font != nil && used[resource.font.ID] {
			fonts = append(fonts, resource)
			delete(promoted, resource.font.ID)
		}
		if resource.image != nil && used[resource.image.ID] {
			images = append(images, resource)
			delete(promoted, resource.image.ID)
		}
		if resource.space != nil && used[resource.space.ID] {
			spaces = append(spaces, *resource.space)
			delete(promoted, resource.space.ID)
		}
	}
	for id := range promoted {
		if name := e.source.reader.resourceFiles[id]; name != "" {
			files[name] = true
		}
	}
	return fonts, images, spaces, slices.Sorted(maps.Keys(files))
}

// page 写出页面尺寸、图层和对象
// 入参: page 页面内容
func (x *ofdXML) page(page PageContent) {
	x.root("Page", nil)
	x.start("Area", nil)
	x.text("PhysicalBox", page.Area.PhysicalBox)
	x.end("Area")
	x.start("Content", nil)
	for _, layer := range page.Content.Layer {
		x.layer(layer)
	}
	x.end("Content")
	x.end("Page")
}

// layer 写出新建图层及其对象
// 入参: layer 图层
func (x *ofdXML) layer(layer Layer) {
	var attrs ofdAttrs
	attrs.add("ID", layer.ID)
	attrs.add("Type", layer.Type)
	x.start("Layer", attrs)
	for _, object := range layer.Objects {
		x.object(object, false)
	}
	x.end("Layer")
}

// resources 写出文档资源索引
// 入参: fonts 字体资源, images 图片资源, spaces 颜色空间
func (x *ofdXML) resources(fonts, images []editorResource, spaces []ColorSpace) {
	x.root("Res", ofdAttrs{{Name: xml.Name{Local: "BaseLoc"}, Value: "Res"}})
	if len(spaces) != 0 {
		x.start("ColorSpaces", nil)
		for _, space := range spaces {
			x.start("ColorSpace", ofdAttrs{{Name: xml.Name{Local: "ID"}, Value: space.ID}, {Name: xml.Name{Local: "Type"}, Value: space.Type}, {Name: xml.Name{Local: "BitsPerComponent"}, Value: strconv.Itoa(space.BitsPerComponent)}})
			x.end("ColorSpace")
		}
		x.end("ColorSpaces")
	}
	if len(fonts) != 0 {
		x.start("Fonts", nil)
		for _, resource := range fonts {
			font := resource.font
			var attrs ofdAttrs
			attrs.add("ID", font.ID)
			attrs.add("FontName", font.FontName)
			attrs.add("FamilyName", font.FamilyName)
			attrs.add("Charset", font.Charset)
			if font.Bold {
				attrs.add("Bold", "true")
			}
			if font.Italic {
				attrs.add("Italic", "true")
			}
			if font.FixedWidth {
				attrs.add("FixedWidth", "true")
			}
			x.start("Font", attrs)
			x.text("FontFile", font.FontFile)
			x.end("Font")
		}
		x.end("Fonts")
	}
	if len(images) != 0 {
		x.start("MultiMedias", nil)
		for _, resource := range images {
			image := resource.image
			var attrs ofdAttrs
			attrs.add("ID", image.ID)
			attrs.add("Type", image.Type)
			attrs.add("Format", image.Format)
			x.start("MultiMedia", attrs)
			x.text("MediaFile", image.MediaFile)
			x.end("MultiMedia")
		}
		x.end("MultiMedias")
	}
	x.end("Res")
}

// ofdCountingWriter 记录实际输出字节数
type ofdCountingWriter struct {
	writer io.Writer
	count  int64
}

// Write 写入并累计字节数
// 入参: data 数据
// 返回: int 字节数, error 错误信息
func (w *ofdCountingWriter) Write(data []byte) (int, error) {
	n, err := w.writer.Write(data)
	w.count += int64(n)
	if err == nil && n != len(data) {
		err = io.ErrShortWrite
	}
	return n, err
}

// ofdXML 使用标准ofd命名空间写出XML
type ofdXML struct {
	encoder *xml.Encoder
	err     error
}

// newOFDXML 创建XML编码器
// 入参: writer 输出流
// 返回: *ofdXML 编码器
func newOFDXML(writer io.Writer) *ofdXML {
	_, err := io.WriteString(writer, xml.Header)
	return &ofdXML{encoder: xml.NewEncoder(writer), err: err}
}

// token 写入XML标记并保留首个错误
// 入参: token XML标记
func (x *ofdXML) token(token xml.Token) {
	if x.err == nil {
		x.err = x.encoder.EncodeToken(token)
	}
}

// root 写入声明命名空间的根节点
// 入参: name 节点名, attrs 属性
func (x *ofdXML) root(name string, attrs ofdAttrs) {
	attrs.add("xmlns:ofd", ofdNamespace)
	x.start(name, attrs)
}

// start 写入节点起始标记
// 入参: name 节点名, attrs 属性
func (x *ofdXML) start(name string, attrs ofdAttrs) {
	x.token(xml.StartElement{Name: xml.Name{Local: "ofd:" + name}, Attr: attrs})
}

// end 写入节点结束标记
// 入参: name 节点名
func (x *ofdXML) end(name string) {
	x.token(xml.EndElement{Name: xml.Name{Local: "ofd:" + name}})
}

// text 写入文本节点
// 入参: name 节点名, value 文本
func (x *ofdXML) text(name, value string) {
	x.start(name, nil)
	x.token(xml.CharData(value))
	x.end(name)
}

// finish 完成XML输出
// 返回: error 错误信息
func (x *ofdXML) finish() error {
	if x.err != nil {
		return x.err
	}
	return x.encoder.Close()
}

// ofdAttrs OFD节点属性
type ofdAttrs []xml.Attr

// add 添加非空属性
// 入参: name 属性名, value 属性值
func (a *ofdAttrs) add(name, value string) {
	if value != "" {
		*a = append(*a, xml.Attr{Name: xml.Name{Local: name}, Value: value})
	}
}

// number 添加非零数值属性
// 入参: name 属性名, value 数值
func (a *ofdAttrs) number(name string, value float64) {
	if value != 0 {
		a.add(name, ofdNumber(value))
	}
}

// flag 添加显式布尔属性
// 入参: name 属性名, value 布尔值
func (a *ofdAttrs) flag(name string, value *bool) {
	if value != nil {
		a.add(name, strconv.FormatBool(*value))
	}
}

// alpha 添加显式透明度
// 入参: value 透明度
func (a *ofdAttrs) alpha(value *int) {
	if value != nil {
		a.add("Alpha", strconv.Itoa(*value))
	}
}

// encodeOFDXML 编码文档节点，用于保存和独立副本
// 入参: encode 节点写入方法
// 返回: []byte XML数据, error 错误信息
func encodeOFDXML(encode func(*ofdXML)) ([]byte, error) {
	var data bytes.Buffer
	x := newOFDXML(&data)
	encode(x)
	if err := x.finish(); err != nil {
		return nil, err
	}
	return data.Bytes(), nil
}

// object 按OFD规定顺序写出基本对象
// 入参: object 图形对象, root 是否为根节点
func (x *ofdXML) object(object GraphicObject, root bool) {
	var attrs ofdAttrs
	var fill, stroke *FillColor
	var actions []Action
	if root {
		attrs.add("xmlns:ofd", ofdNamespace)
	}
	switch object.Type {
	case "TextObject":
		obj := object.TextObject
		attrs.add("ID", obj.ID)
		attrs.add("DrawParam", obj.DrawParam)
		attrs.add("Boundary", obj.Boundary)
		attrs.add("CTM", obj.CTM)
		attrs.add("Font", obj.Font)
		attrs.number("Size", obj.Size)
		attrs.number("HScale", obj.HScale)
		attrs.number("VScale", obj.VScale)
		attrs.add("Decoration", obj.Decoration)
		attrs.number("Weight", float64(obj.Weight))
		attrs.number("ReadDirection", float64(obj.ReadDirection))
		attrs.number("CharDirection", float64(obj.CharDirection))
		attrs.number("LineWidth", obj.LineWidth)
		attrs.number("MiterLimit", obj.MiterLimit)
		attrs.add("Join", obj.Join)
		if obj.Italic {
			attrs.add("Italic", "true")
		}
		attrs.flag("Visible", obj.Visible)
		attrs.flag("Stroke", obj.Stroke)
		attrs.flag("Fill", obj.Fill)
		attrs.alpha(obj.Alpha)
		fill, stroke = obj.FillColor, (*FillColor)(obj.StrokeColor)
		actions = obj.Actions
	case "PathObject", "Path":
		obj := object.PathObject
		attrs.add("ID", obj.ID)
		attrs.add("DrawParam", obj.DrawParam)
		attrs.add("Boundary", obj.Boundary)
		attrs.add("CTM", obj.CTM)
		attrs.number("LineWidth", obj.LineWidth)
		attrs.number("MiterLimit", obj.MiterLimit)
		attrs.add("Join", obj.Join)
		attrs.add("Cap", obj.Cap)
		attrs.add("Rule", obj.Rule)
		if obj.dashPatternSet {
			attrs = append(attrs, xml.Attr{Name: xml.Name{Local: "DashPattern"}, Value: obj.DashPattern})
		} else {
			attrs.add("DashPattern", obj.DashPattern)
		}
		if obj.DashOffset != nil {
			attrs.add("DashOffset", ofdNumber(*obj.DashOffset))
		}
		attrs.flag("Visible", obj.Visible)
		attrs.flag("Stroke", obj.Stroke)
		attrs.flag("Fill", obj.Fill)
		attrs.alpha(obj.Alpha)
		fill, stroke = obj.FillColor, (*FillColor)(obj.StrokeColor)
		actions = obj.Actions
	case "ImageObject":
		obj := object.ImageObject
		attrs.add("ID", obj.ID)
		attrs.add("Boundary", obj.Boundary)
		attrs.add("CTM", obj.CTM)
		attrs.add("ResourceID", obj.ResourceID)
		attrs.add("ImageMask", obj.ImageMask)
		attrs.flag("Visible", obj.Visible)
		attrs.alpha(obj.Alpha)
		actions = obj.Actions
	case "CompositeObject", "CompositeGraphicUnit":
		obj := object.CompositeGraphicUnit
		attrs.add("ID", obj.ID)
		attrs.add("Boundary", obj.Boundary)
		attrs.add("CTM", obj.CTM)
		attrs.add("ResourceID", obj.ResourceID)
		attrs.add("DrawParam", obj.DrawParam)
		attrs.flag("Visible", obj.Visible)
		attrs.alpha(obj.Alpha)
		actions = obj.Actions
	}
	x.start(object.Type, attrs)
	x.actions(actions)
	if object.Type == "ImageObject" {
		x.clips(object.ImageObject.Clips)
		x.border(object.ImageObject.Border)
	} else if object.Type == "CompositeObject" || object.Type == "CompositeGraphicUnit" {
		x.clips(object.CompositeGraphicUnit.Clips)
	} else if object.Type == "PathObject" || object.Type == "Path" {
		x.clips(object.PathObject.Clips)
		x.color("StrokeColor", stroke)
		x.color("FillColor", fill)
		x.text("AbbreviatedData", object.PathObject.AbbreviatedData)
	} else if object.Type == "TextObject" {
		x.clips(object.TextObject.Clips)
		x.color("FillColor", fill)
		x.color("StrokeColor", stroke)
		offset, index := 0, 0
		for _, code := range object.TextObject.TextCode {
			end := offset + len(textCodeRunes(code.Value))
			for index < len(object.TextObject.CGTransform) && object.TextObject.CGTransform[index].CodePosition < end {
				transform := object.TextObject.CGTransform[index]
				attrs := ofdAttrs{
					{Name: xml.Name{Local: "CodePosition"}, Value: strconv.Itoa(transform.CodePosition - offset)},
					{Name: xml.Name{Local: "CodeCount"}, Value: strconv.Itoa(transform.CodeCount)},
					{Name: xml.Name{Local: "GlyphCount"}, Value: strconv.Itoa(transform.GlyphCount)},
				}
				x.start("CGTransform", attrs)
				x.text("Glyphs", transform.Glyphs)
				x.end("CGTransform")
				index++
			}
			var attrs ofdAttrs
			attrs.add("X", code.X)
			attrs.add("Y", code.Y)
			attrs.add("DeltaX", code.DeltaX)
			attrs.add("DeltaY", code.DeltaY)
			x.textCode(code.Value, attrs)
			offset = end
		}
	}
	x.end(object.Type)
}

// clips 写出对象路径裁剪，保留裁剪集合、区域及路径的变换
// 入参: clips 裁剪集合，nil不输出节点
func (x *ofdXML) clips(clips *Clips) {
	if clips == nil {
		return
	}
	var attrs ofdAttrs
	attrs.flag("TransFlag", clips.TransFlag)
	x.start("Clips", attrs)
	for _, clip := range clips.Clip {
		x.start("Clip", nil)
		for _, area := range clip.Area {
			var attrs ofdAttrs
			attrs.add("CTM", area.CTM)
			attrs.add("DrawParam", area.DrawParam)
			x.start("Area", attrs)
			for _, path := range area.Path {
				x.object(GraphicObject{Type: "Path", PathObject: path}, false)
			}
			x.end("Area")
		}
		x.end("Clip")
	}
	x.end("Clips")
}

// textCode 使用XML字符引用转义空格，避免依赖阅读器保留原始空白
// 入参: value OFD文字内容, attrs 文字定位属性
func (x *ofdXML) textCode(value string, attrs ofdAttrs) {
	if x.err != nil {
		return
	}
	var escaped bytes.Buffer
	if x.err = xml.EscapeText(&escaped, []byte(value)); x.err != nil {
		return
	}
	content := struct {
		Text []byte `xml:",innerxml"`
	}{Text: bytes.ReplaceAll(escaped.Bytes(), []byte(" "), []byte("&#x20;"))}
	x.err = x.encoder.EncodeElement(content, xml.StartElement{Name: xml.Name{Local: "ofd:TextCode"}, Attr: attrs})
}

// color 写出纯色、渐变和图案，保留颜色空间与透明度
// 入参: name 节点名, color 颜色
func (x *ofdXML) color(name string, color *FillColor) {
	if color == nil {
		return
	}
	var attrs ofdAttrs
	attrs.add("Value", color.Value)
	attrs.add("ColorSpace", color.ColorSpace)
	if color.Index != nil {
		attrs.add("Index", strconv.Itoa(*color.Index))
	}
	attrs.alpha(color.Alpha)
	x.start(name, attrs)
	if color.AxialShd != nil {
		shading := color.AxialShd
		x.shading("AxialShd", shadingAttrs(shading.MapType, shading.MapUnit, shading.Extend, shading.StartPoint, shading.EndPoint), shading.Segment)
	}
	if color.RadialShd != nil {
		shading := color.RadialShd
		attrs := shadingAttrs(shading.MapType, shading.MapUnit, shading.Extend, shading.StartPoint, shading.EndPoint)
		attrs.add("StartRadius", ofdNumber(shading.StartRadius))
		attrs.add("EndRadius", ofdNumber(shading.EndRadius))
		attrs.number("Eccentricity", shading.Eccentricity)
		attrs.number("Angle", shading.Angle)
		x.shading("RadialShd", attrs, shading.Segment)
	}
	if color.Pattern != nil {
		x.pattern(color.Pattern)
	}
	x.end(name)
}

// shadingAttrs 编码轴向和径向渐变的共同属性
// 入参: mapType 映射方式, mapUnit 映射周期, extend 延伸方式, start、end 渐变端点
// 返回: ofdAttrs 属性集合
func shadingAttrs(mapType string, mapUnit float64, extend, start, end string) ofdAttrs {
	var attrs ofdAttrs
	attrs.add("MapType", mapType)
	attrs.number("MapUnit", mapUnit)
	attrs.add("Extend", extend)
	attrs.add("StartPoint", start)
	attrs.add("EndPoint", end)
	return attrs
}

// shading 写出渐变分段，保留未显式设置的位置
// 入参: name 渐变类型, attrs 属性, segments 色标
func (x *ofdXML) shading(name string, attrs ofdAttrs, segments []ShdSegment) {
	x.start(name, attrs)
	for _, segment := range segments {
		var attrs ofdAttrs
		if !segment.positionMissing {
			attrs.add("Position", ofdNumber(segment.Position))
		}
		x.start("Segment", attrs)
		x.element("Color", segment.Color)
		x.end("Segment")
	}
	x.end(name)
}

// element 写出具有标准XML标签的子树，显式声明OFD命名空间
// 入参: name 元素名称, value 元素内容
func (x *ofdXML) element(name string, value any) {
	if x.err == nil {
		x.err = x.encoder.EncodeElement(value, xml.StartElement{Name: xml.Name{Space: ofdNamespace, Local: name}})
	}
}

// border 写出图片边框及其绘制颜色
// 入参: border 边框，nil不输出节点
func (x *ofdXML) border(border *ImageBorder) {
	if border == nil {
		return
	}
	var attrs ofdAttrs
	if border.LineWidth != nil {
		attrs.add("LineWidth", ofdNumber(*border.LineWidth))
	}
	attrs.number("HorizonalCornerRadius", border.HorizonalCornerRadius)
	attrs.number("VerticalCornerRadius", border.VerticalCornerRadius)
	attrs.number("DashOffset", border.DashOffset)
	attrs.add("DashPattern", border.DashPattern)
	x.start("Border", attrs)
	x.color("BorderColor", (*FillColor)(border.BorderColor))
	x.end("Border")
}

// pattern 写出图案单元，保留对象绘制顺序
// 入参: pattern 图案
func (x *ofdXML) pattern(pattern *Pattern) {
	var attrs ofdAttrs
	attrs.number("Width", pattern.Width)
	attrs.number("Height", pattern.Height)
	attrs.number("XStep", pattern.XStep)
	attrs.number("YStep", pattern.YStep)
	attrs.add("ReflectMethod", pattern.ReflectMethod)
	attrs.add("RelativeTo", pattern.RelativeTo)
	attrs.add("CTM", pattern.CTM)
	x.start("Pattern", attrs)
	x.start("CellContent", nil)
	for _, object := range pattern.CellContent.Objects {
		x.object(object, false)
	}
	x.end("CellContent")
	x.end("Pattern")
}

// actions 写出对象动作及精确点击区域，不检查链接可达性
// 入参: actions 动作列表
func (x *ofdXML) actions(actions []Action) {
	if len(actions) == 0 {
		return
	}
	x.start("Actions", nil)
	for _, action := range actions {
		var attrs ofdAttrs
		attrs.add("Event", action.Event)
		x.start("Action", attrs)
		if action.Region != nil {
			x.start("Region", nil)
			for _, area := range action.Region.Area {
				x.start("Area", ofdAttrs{{Name: xml.Name{Local: "Start"}, Value: area.Start}})
				for _, command := range area.Command {
					var attrs ofdAttrs
					for _, pair := range [][2]string{{"Point1", command.Point1}, {"Point2", command.Point2}, {"Point3", command.Point3}, {"EllipseSize", command.EllipseSize}, {"RotationAngle", command.RotationAngle}, {"LargeArc", command.LargeArc}, {"SweepDirection", command.SweepDirection}, {"EndPoint", command.EndPoint}} {
						attrs.add(pair[0], pair[1])
					}
					x.start(command.Type, attrs)
					x.end(command.Type)
				}
				x.end("Area")
			}
			x.end("Region")
		}
		if action.Goto != nil {
			x.start("Goto", nil)
			if dest := action.Goto.Dest; dest != nil {
				attrs := ofdAttrs{{Name: xml.Name{Local: "Type"}, Value: dest.Type}, {Name: xml.Name{Local: "PageID"}, Value: dest.PageID}}
				switch dest.Type {
				case "XYZ":
					attrs.add("Left", ofdNumber(dest.Left))
					attrs.add("Top", ofdNumber(dest.Top))
					attrs.add("Zoom", ofdNumber(dest.Zoom))
				case "FitH":
					attrs.add("Top", ofdNumber(dest.Top))
				case "FitV":
					attrs.add("Left", ofdNumber(dest.Left))
				case "FitR":
					attrs.add("Left", ofdNumber(dest.Left))
					attrs.add("Right", ofdNumber(dest.Right))
					attrs.add("Top", ofdNumber(dest.Top))
					attrs.add("Bottom", ofdNumber(dest.Bottom))
				}
				x.start("Dest", attrs)
				x.end("Dest")
			}
			if action.Goto.Bookmark != nil {
				x.element("Bookmark", action.Goto.Bookmark)
			}
			x.end("Goto")
		}
		if action.URI != nil {
			x.element("URI", action.URI)
		}
		if action.GotoA != nil {
			x.element("GotoA", action.GotoA)
		}
		if action.Sound != nil {
			x.element("Sound", action.Sound)
		}
		if action.Movie != nil {
			x.element("Movie", action.Movie)
		}
		x.end("Action")
	}
	x.end("Actions")
}