// 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.

//go:build js && wasm

package webui

import (
	"bufio"
	"bytes"
	"context"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"image"
	"io"
	"math"
	"strconv"
	"syscall/js"

	"github.com/xiaoqidun/ofdgo"
)

// exportWriter 分块传递导出数据
type exportWriter struct {
	write js.Value
}

// Write 将数据块交给浏览器保存
// 入参: data 导出数据
// 返回: int 写入长度, error 错误信息
func (w exportWriter) Write(data []byte) (int, error) {
	size := len(data)
	for len(data) > 0 {
		n := min(len(data), 1<<20)
		if err := awaitExport(w.write, bytesToJS(data[:n])); err != nil {
			return size - len(data), err
		}
		data = data[n:]
	}
	return size, nil
}

// awaitExport 等待浏览器处理导出检查点
// 入参: fn 浏览器回调, args 回调参数
// 返回: error 写入错误或取消原因
func awaitExport(fn js.Value, args ...any) error {
	done := make(chan error)
	callback := js.FuncOf(func(this js.Value, args []js.Value) any {
		var err error
		if args[1].Bool() {
			err = context.Canceled
		} else if message := args[0].String(); message != "" {
			err = fmt.Errorf("%s", message)
		}
		done <- err
		return nil
	})
	defer callback.Release()
	fn.Invoke(append(args, callback)...)
	return <-done
}

// currentSession 当前WebUI文档会话
var currentSession *Session

// apiResult 浏览器接口返回结果
type apiResult struct {
	OK    bool   `json:"ok"`
	Error string `json:"error,omitempty"`
	Data  any    `json:"data,omitempty"`
}

// RunWASM 注册浏览器WASM接口并阻塞运行
func RunWASM() {
	registerCallback("ofdgoOpen", openDocument)
	registerCallback("ofdgoConfigure", configureDocument)
	registerCallback("ofdgoDocumentInfo", documentInfo)
	registerCallback("ofdgoRenderPage", renderPage)
	registerCallback("ofdgoSVGFontData", svgFontData)
	registerCallback("ofdgoSearchPage", searchPage)
	registerCallback("ofdgoPageTextString", pageTextString)
	registerCallback("ofdgoExportFormats", exportFormats)
	registerCallback("ofdgoParsePageRange", parsePageRange)
	registerExportCallback("ofdgoExportPage", exportPage)
	registerExportCallback("ofdgoExportDocument", exportDocument)
	registerExportCallback("ofdgoExportAttachment", exportAttachment)
	registerCallback("ofdgoMatchFontFiles", matchFontFiles)
	registerCallback("ofdgoCreateDocument", createDocument)
	registerCallback("ofdgoEditDocument", editDocument)
	registerCallback("ofdgoChangePage", changePage)
	registerCallback("ofdgoInsertText", insertText)
	registerCallback("ofdgoUpdateText", updateText)
	registerCallback("ofdgoInsertImage", insertImage)
	registerCallback("ofdgoInsertShape", insertShape)
	registerCallback("ofdgoUpdatePathStyle", updatePathStyle)
	registerCallback("ofdgoReplaceImage", replaceImage)
	registerCallback("ofdgoEditorFont", editorFont)
	registerCallback("ofdgoAlignObject", alignObject)
	registerCallback("ofdgoTransformObject", transformObject)
	registerCallback("ofdgoReshapeObject", reshapeObject)
	registerCallback("ofdgoLayoutText", layoutText)
	registerCallback("ofdgoTransformObjects", transformObjects)
	registerCallback("ofdgoAlignObjects", alignObjects)
	registerCallback("ofdgoDeleteObjects", deleteObjects)
	registerCallback("ofdgoCopyObjects", copyObjects)
	registerCallback("ofdgoCaptureObjects", captureObjects)
	registerCallback("ofdgoPasteObjects", pasteObjects)
	registerCallback("ofdgoOrderObjects", orderObjects)
	registerCallback("ofdgoDistributeObjects", distributeObjects)
	registerCallback("ofdgoRotateObjects", rotateObjects)
	registerCallback("ofdgoFlipObjects", flipObjects)
	registerCallback("ofdgoCropImage", cropImage)
	registerCallback("ofdgoFitImage", fitImage)
	registerCallback("ofdgoPreviewImage", previewImage)
	registerCallback("ofdgoDeleteObject", deleteObject)
	registerCallback("ofdgoUndo", func([]js.Value) (any, error) { return restoreEditor(false) })
	registerCallback("ofdgoRedo", func([]js.Value) (any, error) { return restoreEditor(true) })
	registerExportCallback("ofdgoSaveDocument", saveDocument)
	select {}
}

// registerCallback 注册浏览器回调函数
// 入参: name 回调名称, fn 回调函数
func registerCallback(name string, fn func([]js.Value) (any, error)) {
	cb := js.FuncOf(func(this js.Value, args []js.Value) any {
		return callbackResult(fn, args)
	})
	js.Global().Set(name, cb)
}

// registerExportCallback 异步导出，为浏览器处理数据块让出事件循环
// 入参: name 回调名称, fn 回调函数
func registerExportCallback(name string, fn func([]js.Value) (any, error)) {
	cb := js.FuncOf(func(this js.Value, args []js.Value) any {
		executor := js.FuncOf(func(this js.Value, callbacks []js.Value) any {
			resolve := callbacks[0]
			go func() {
				resolve.Invoke(callbackResult(fn, args))
			}()
			return nil
		})
		defer executor.Release()
		return js.Global().Get("Promise").New(executor)
	})
	js.Global().Set(name, cb)
}

// callbackResult 转换浏览器接口结果
// 入参: fn 回调函数, args 回调参数
// 返回: any 浏览器结果
func callbackResult(fn func([]js.Value) (any, error), args []js.Value) any {
	data, err := safeCall(fn, args)
	if err != nil {
		return encodeResult(apiResult{OK: false, Error: err.Error()})
	}
	if result, ok := data.(js.Value); ok {
		return result
	}
	return encodeResult(apiResult{OK: true, Data: data})
}

// safeCall 调用浏览器回调并转换异常
// 入参: fn 回调函数, args 回调参数
// 返回: any 回调结果, error 错误信息
func safeCall(fn func([]js.Value) (any, error), args []js.Value) (data any, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = fmt.Errorf("%v", r)
		}
	}()
	return fn(args)
}

// openDocument 打开OFD文档
// 入参: args 浏览器参数
// 返回: any 文档信息, error 错误信息
func openDocument(args []js.Value) (any, error) {
	if len(args) < 3 {
		return nil, fmt.Errorf("missing open arguments")
	}
	data, err := bytesFromJS(args[0])
	if err != nil {
		return nil, err
	}
	fonts, err := fontsFromJS(args[1])
	if err != nil {
		return nil, err
	}
	renderAnnotations := args[2].Bool()
	currentEditor = nil
	copiedObjects = nil
	if currentSession != nil {
		_ = currentSession.Close()
		currentSession = nil
	}
	session, err := Open(data, OpenOptions{Fonts: fonts, RenderAnnotations: renderAnnotations})
	if err != nil {
		return nil, err
	}
	currentSession = session
	return currentSession.Summary(), nil
}

// configureDocument 更新当前会话的字体和注解设置
// 入参: args 浏览器参数
// 返回: any 文档信息, error 错误信息
func configureDocument(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	if !args[0].IsNull() && !args[0].IsUndefined() {
		fonts, err := fontsFromJS(args[0])
		if err != nil {
			return nil, err
		}
		if err := currentSession.SetFonts(fonts); err != nil {
			return nil, err
		}
	}
	if currentSession.Renderer.RenderAnnotations != args[1].Bool() {
		currentSession.Renderer.RenderAnnotations = args[1].Bool()
		clear(currentSession.textCache)
	}
	return currentSession.Summary(), nil
}

// documentInfo 获取首屏之后加载的字体统计和验签结果
// 入参: args 浏览器参数
// 返回: any 文档信息, error 错误信息
func documentInfo(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	return currentSession.Info(), nil
}

// exportAttachment 分块导出附件
// 入参: args 浏览器参数
// 返回: any 附件数据, error 错误信息
func exportAttachment(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	stream, err := currentSession.Reader.OpenAttachment(args[0].String())
	if err != nil {
		return nil, err
	}
	defer stream.Close()
	writer := bufio.NewWriterSize(exportWriter{write: args[1]}, 1<<20)
	if _, err := io.Copy(writer, stream); err != nil {
		return nil, err
	}
	if err := writer.Flush(); err != nil {
		return nil, err
	}
	return successResult(map[string]any{
		"mime": "application/octet-stream",
	}), nil
}

// svgFontData 读取SVG字体资源
// 入参: args 浏览器参数
// 返回: any 字体数据, error 错误信息
func svgFontData(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	data, err := currentSession.SVGFontData(args[0].String())
	if err != nil {
		return nil, err
	}
	return successResult(map[string]any{"bytes": bytesToJS(data)}), nil
}

// renderPage 渲染OFD页面
// 入参: args 浏览器参数
// 返回: any 页面SVG结果, error 错误信息
func renderPage(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	if len(args) == 0 {
		return nil, fmt.Errorf("missing page index")
	}
	page, err := currentSession.RenderPageSVG(args[0].Int())
	if err != nil {
		return nil, err
	}
	text, err := currentSession.PageText(args[0].Int())
	if err != nil {
		return nil, err
	}
	textData, err := json.Marshal(text)
	if err != nil {
		return nil, err
	}
	objects, err := editorObjects(args[0].Int(), text)
	if err != nil {
		return nil, err
	}
	links := make([]any, len(page.Links))
	for i, link := range page.Links {
		links[i] = map[string]any{
			"uri":    link.URI,
			"x":      link.Box.X,
			"y":      link.Box.Y,
			"width":  link.Box.W,
			"height": link.Box.H,
		}
	}
	fonts := make([]any, len(page.Fonts))
	for i, font := range page.Fonts {
		fonts[i] = map[string]any{"name": font.Name, "weight": font.Weight, "style": font.Style}
	}
	return successResult(map[string]any{
		"index":   page.Index,
		"number":  page.Number,
		"id":      page.ID,
		"width":   page.Width,
		"height":  page.Height,
		"svg":     page.SVG,
		"links":   links,
		"fonts":   fonts,
		"images":  svgImagesToJS(page.Images),
		"text":    string(textData),
		"objects": objects,
	}), nil
}

// pageTextString 提取OFD页面原文
// 入参: args 浏览器参数
// 返回: any 页面原文, error 错误信息
func pageTextString(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	return currentSession.PageTextString(args[0].Int())
}

// searchPage 搜索OFD页面文字
// 入参: args 浏览器参数
// 返回: any 搜索结果, error 错误信息
func searchPage(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	return currentSession.SearchPage(args[0].Int(), args[1].String())
}

// exportFormats 获取导出格式
// 入参: args 浏览器参数
// 返回: any 导出格式, error 错误信息
func exportFormats(args []js.Value) (any, error) {
	return ExportFormats(), nil
}

// parsePageRange 解析当前文档的导出页码
// 入参: args 浏览器参数
// 返回: any 页面索引, error 错误信息
func parsePageRange(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	count, err := currentSession.Reader.PageCount()
	if err != nil {
		return nil, err
	}
	return ofdgo.ParsePageRange(args[0].String(), count)
}

// exportPage 导出OFD单页
// 入参: args 浏览器参数
// 返回: any 导出结果, error 错误信息
func exportPage(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	if len(args) < 4 {
		return nil, fmt.Errorf("missing export page arguments")
	}
	writer := bufio.NewWriterSize(exportWriter{write: args[3]}, 1<<20)
	format, err := currentSession.ExportPage(args[0].Int(), args[1].String(), args[2].Float(), writer)
	if err != nil {
		return nil, err
	}
	if err := writer.Flush(); err != nil {
		return nil, err
	}
	return successResult(map[string]any{
		"label": format.Label,
		"mime":  format.MIME,
	}), nil
}

// exportDocument 导出OFD文档
// 入参: args 浏览器参数
// 返回: any 导出结果, error 错误信息
func exportDocument(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	renderer := currentSession.Renderer
	renderer.OnExportProgress = func(completed, total int) error {
		return awaitExport(args[4], completed, total)
	}
	defer func() { renderer.OnExportProgress = nil }()
	var indices []int
	if !args[2].IsNull() {
		indices = make([]int, args[2].Length())
		for i := range indices {
			indices[i] = args[2].Index(i).Int()
		}
	}
	writer := bufio.NewWriterSize(exportWriter{write: args[3]}, 1<<20)
	format, err := currentSession.ExportDocument(args[0].String(), args[1].Float(), writer, indices...)
	if err != nil {
		return nil, err
	}
	if err := writer.Flush(); err != nil {
		return nil, err
	}
	return successResult(map[string]any{
		"label": format.Label,
		"mime":  format.MIME,
	}), nil
}

// successResult 创建成功接口结果
// 入参: data 返回数据
// 返回: js.Value 接口结果
func successResult(data any) js.Value {
	result := js.Global().Get("Object").New()
	result.Set("ok", true)
	result.Set("data", data)
	return result
}

// bytesToJS 将字节数据转换为Uint8Array
// 入参: data 字节数据
// 返回: js.Value Uint8Array对象
func bytesToJS(data []byte) js.Value {
	value := js.Global().Get("Uint8Array").New(len(data))
	js.CopyBytesToJS(value, data)
	return value
}

// matchFontFiles 匹配文档所需的字体文件
// 入参: args 浏览器参数
// 返回: any 匹配的字体文件名称, error 错误信息
func matchFontFiles(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	return currentSession.Reader.MatchFontFiles(stringsFromJS(args[0]))
}

// bytesFromJS 从浏览器值读取二进制数据
// 入参: value 浏览器值
// 返回: []byte 二进制数据, error 错误信息
func bytesFromJS(value js.Value) ([]byte, error) {
	if value.IsUndefined() || value.IsNull() {
		return nil, fmt.Errorf("missing binary data")
	}
	uint8Array := js.Global().Get("Uint8Array")
	arrayBuffer := js.Global().Get("ArrayBuffer")
	if value.InstanceOf(arrayBuffer) {
		value = uint8Array.New(value)
	}
	if !value.InstanceOf(uint8Array) {
		return nil, fmt.Errorf("binary data must be Uint8Array or ArrayBuffer")
	}
	data := make([]byte, value.Get("byteLength").Int())
	if n := js.CopyBytesToGo(data, value); n != len(data) {
		return nil, fmt.Errorf("copied %d of %d bytes", n, len(data))
	}
	return data, nil
}

// fontsFromJS 从浏览器值读取字体文件
// 入参: value 浏览器值
// 返回: []FontFile 字体文件, error 错误信息
func fontsFromJS(value js.Value) ([]FontFile, error) {
	if value.IsUndefined() || value.IsNull() {
		return nil, nil
	}
	length := value.Get("length").Int()
	fonts := make([]FontFile, 0, length)
	for i := 0; i < length; i++ {
		item := value.Index(i)
		data, err := bytesFromJS(item.Get("data"))
		if err != nil {
			return nil, err
		}
		fonts = append(fonts, FontFile{Name: item.Get("name").String(), Data: data})
	}
	return fonts, nil
}

// stringsFromJS 从浏览器值读取字符串列表
// 入参: value 浏览器值
// 返回: []string 字符串列表
func stringsFromJS(value js.Value) []string {
	items := make([]string, value.Length())
	for i := range items {
		items[i] = value.Index(i).String()
	}
	return items
}

// encodeResult 编码浏览器接口返回结果
// 入参: result 返回结果
// 返回: string JSON字符串
func encodeResult(result apiResult) string {
	data, err := json.Marshal(result)
	if err != nil {
		fallback, _ := json.Marshal(apiResult{OK: false, Error: err.Error()})
		return string(fallback)
	}
	return string(data)
}

// currentEditor 当前编辑文档
var currentEditor *ofdgo.Editor

// editorClipboard 当前编辑文档中的对象快照与剪贴板标识。
type editorClipboard struct {
	token   string
	objects []ofdgo.GraphicObject
}

// copiedObjects 当前对象剪贴板，不保存字体或图片的重复数据。
var copiedObjects *editorClipboard

// editorInfo 编辑文档信息与操作状态
type editorInfo struct {
	DocumentInfo
	Revision         uint64            `json:"revision"`
	CanUndo          bool              `json:"canUndo"`
	CanRedo          bool              `json:"canRedo"`
	PageCapabilities []map[string]bool `json:"pageCapabilities"`
	EditWarnings     []string          `json:"editWarnings,omitempty"`
}

// editorPageInfo 页面操作结果与目标页面
type editorPageInfo struct {
	editorInfo
	PageIndex int `json:"pageIndex"`
}

// editorSelectionInfo 对象复制结果及新选区。
type editorSelectionInfo struct {
	editorInfo
	SelectedIDs []string `json:"selectedIDs"`
}

// editorSummary 获取当前编辑文档状态
// 返回: editorInfo 文档信息
func editorSummary() editorInfo {
	info := editorInfo{DocumentInfo: currentSession.Summary(), Revision: currentEditor.Revision(), CanUndo: currentEditor.CanUndo(), CanRedo: currentEditor.CanRedo()}
	if !currentSession.doc.Permissions.Edit {
		info.EditWarnings = append(info.EditWarnings, "原文件声明不允许编辑")
	}
	if currentSession.doc.Signatures != "" {
		info.EditWarnings = append(info.EditWarnings, "修改文档可能使原签名失效")
	}
	for i := 0; i < currentEditor.PageCount(); i++ {
		capability, _ := currentEditor.PageCapabilities(i)
		info.PageCapabilities = append(info.PageCapabilities, map[string]bool{"insert": capability.Insert, "copy": capability.Copy, "delete": capability.Delete, "move": capability.Move, "resize": capability.Resize})
	}
	return info
}

// restoreEditor 撤销或重做并更新预览
// 入参: redo 是否重做
// 返回: any 文档信息, error 错误信息
func restoreEditor(redo bool) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	apply := currentEditor.Undo
	if redo {
		apply = currentEditor.Redo
	}
	if !apply() {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// editorObjects 提供编辑画布的对象范围、文字排版及原始图片边界
// 入参: index 页面索引, text 页面文字
// 返回: []any 对象区域, error 错误信息
func editorObjects(index int, text *ofdgo.PageText) ([]any, error) {
	objects := []any{}
	if currentEditor == nil {
		return objects, nil
	}
	page, err := currentEditor.Page(index)
	if err != nil {
		return nil, err
	}
	textBoxes := make(map[string]ofdgo.Box)
	for _, run := range text.Runs {
		for _, box := range run.Boxes {
			if box.W <= 0 || box.H <= 0 {
				continue
			}
			prev, exists := textBoxes[run.ID]
			if !exists {
				textBoxes[run.ID] = box
				continue
			}
			x, y := math.Min(prev.X, box.X), math.Min(prev.Y, box.Y)
			textBoxes[run.ID] = ofdgo.Box{X: x, Y: y, W: math.Max(prev.X+prev.W, box.X+box.W) - x, H: math.Max(prev.Y+prev.H, box.Y+box.H) - y}
		}
	}
	fonts, err := currentSession.Reader.Fonts()
	if err != nil {
		return nil, err
	}
	fontNames := make(map[string]string, len(fonts))
	for _, font := range fonts {
		fontNames[font.ID] = font.FontName
	}
	for _, layer := range page.Content.Layer {
		for order, object := range layer.Objects {
			var id string
			switch object.Type {
			case "TextObject":
				id = object.TextObject.ID
			case "ImageObject":
				id = object.ImageObject.ID
			case "PathObject":
				id = object.PathObject.ID
			default:
				continue
			}
			capability, err := currentEditor.ObjectCapabilities(index, id)
			if err != nil {
				return nil, err
			}
			if capability.Reason == "nested objects are read-only" {
				continue
			}
			var box ofdgo.Box
			switch object.Type {
			case "TextObject":
				box = textBoxes[id]
			case "ImageObject":
				box, err = ofdgo.ParseBox(object.ImageObject.Boundary)
			case "PathObject":
				box, err = ofdgo.ParseBox(object.PathObject.Boundary)
			}
			if err != nil {
				continue
			}
			if box.W > 0 && box.H > 0 {
				item := map[string]any{"id": id, "type": object.Type, "x": box.X, "y": box.Y, "width": box.W, "height": box.H, "order": order, "count": len(layer.Objects), "layer": layer.ID,
					"capabilities": map[string]any{"update": capability.Update, "replaceFont": capability.ReplaceFont, "reflow": capability.Reflow, "layoutKnown": capability.LayoutKnown, "transform": capability.Transform, "arrange": capability.Arrange, "copy": capability.Copy, "delete": capability.Delete, "order": capability.Order, "reason": capability.Reason}}
				if object.Type == "ImageObject" && capability.Update {
					full, err := object.ImageObject.ImageBounds()
					if err != nil {
						return nil, err
					}
					item["imageBounds"] = editorBox(full)
				}
				if object.Type == "PathObject" && capability.Update {
					path := object.PathObject
					kind, geometry := path.Shape()
					if kind != "" {
						item["shape"] = string(kind)
						item["geometry"] = map[string]any{"x": geometry.X, "y": geometry.Y, "width": geometry.W, "height": geometry.H}
					}
					item["fill"], item["stroke"] = path.Fill != nil && *path.Fill, path.Stroke == nil || *path.Stroke
					item["fillColor"] = editorColorHex(path.FillColor)
					item["strokeColor"] = editorColorHex((*ofdgo.FillColor)(path.StrokeColor))
					item["lineWidth"] = path.LineWidth * editorPathScale(path)
				}
				if object.Type == "TextObject" {
					value, layout := object.TextObject.TextLayout()
					item["text"], item["font"], item["fontName"], item["size"] = value, object.TextObject.Font, fontNames[object.TextObject.Font], object.TextObject.Size
					item["wrap"], item["align"], item["paragraphHeight"] = layout.Wrap, layout.Align, layout.LineHeight
					item["letterSpacing"] = layout.LetterSpacing
					if capability.Reflow {
						frame, err := object.TextObject.TextFrame()
						if err != nil {
							return nil, err
						}
						boundary, _ := ofdgo.ParseBox(object.TextObject.Boundary)
						matrix := ofdgo.TranslationMatrix(boundary.X, boundary.Y).Multiply(ofdgo.NewMatrix(object.TextObject.CTM))
						inverse, _ := matrix.Invert()
						local := inverse.TransformBox(box)
						width := math.Max(object.TextObject.Size, local.X+local.W)
						if layout.Wrap {
							width = frame.W
						}
						frame = ofdgo.Box{W: width, H: math.Max(object.TextObject.Size, local.Y+local.H)}
						item["textFrame"] = map[string]any{"width": frame.W, "height": frame.H, "matrix": editorMatrix(matrix)}
						if layout.Wrap {
							bounds := matrix.TransformBox(frame)
							item["x"], item["y"], item["width"], item["height"] = bounds.X, bounds.Y, bounds.W, bounds.H
						}
					}
					if codes := object.TextObject.TextCode; len(codes) > 1 {
						first, _ := strconv.ParseFloat(codes[0].Y, 64)
						second, _ := strconv.ParseFloat(codes[1].Y, 64)
						item["lineHeight"] = second - first
					}
					if capability.Update {
						item["color"] = editorColorHex(object.TextObject.FillColor)
					}
				}
				objects = append(objects, item)
			}
		}
	}
	return objects, nil
}

// editorFont 读取创作对象的完整内嵌字体，供画布输入使用
// 入参: args 字体资源标识
// 返回: any 字体数据, error 错误信息
func editorFont(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	fonts, err := currentSession.Reader.Fonts()
	if err != nil {
		return nil, err
	}
	for _, font := range fonts {
		if font.ID == args[0].String() {
			data, err := currentSession.Reader.ResData(font.FontFile)
			if err != nil {
				return nil, err
			}
			return successResult(map[string]any{"bytes": bytesToJS(data)}), nil
		}
	}
	return nil, fmt.Errorf("font resource %q not found", args[0].String())
}

// replaceImage 替换图片资源并更新预览
// 入参: args 页码、对象标识、图片数据和适应方式
// 返回: any 文档信息, error 错误信息
func replaceImage(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	data, err := bytesFromJS(args[2])
	if err != nil {
		return nil, err
	}
	revision := currentEditor.Revision()
	if err := currentEditor.ReplaceImage(args[0].Int(), args[1].String(), data, args[3].String()); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// alignObject 将对象对齐页面并更新预览
// 入参: args 页码、对象标识和对齐方式
// 返回: any 文档信息, error 错误信息
func alignObject(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	revision := currentEditor.Revision()
	if err := currentEditor.AlignObject(args[0].Int(), args[1].String(), args[2].String()); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// transformObject 等比缩放后平移对象
// 入参: args 页码、对象标识、位移和缩放比例
// 返回: any 文档信息, error 错误信息
func transformObject(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	page, id := args[0].Int(), args[1].String()
	revision := currentEditor.Revision()
	if err := currentEditor.TransformObject(page, id, args[2].Float(), args[3].Float(), args[4].Float()); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// reshapeObject 调整基本图形的尺寸或直线端点，保留绘制样式
// 入参: args 页码、对象标识和页面几何范围
// 返回: any 文档信息, error 错误信息
func reshapeObject(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	page, id := args[0].Int(), args[1].String()
	object, err := currentEditor.Object(page, id)
	if err != nil {
		return nil, err
	}
	if object.Type != "PathObject" {
		return nil, fmt.Errorf("object is not a path")
	}
	object.PathObject, err = object.PathObject.Reshape(ofdgo.Box{X: args[2].Float(), Y: args[3].Float(), W: args[4].Float(), H: args[5].Float()})
	if err != nil {
		return nil, err
	}
	revision := currentEditor.Revision()
	if err := currentEditor.UpdateObject(page, id, object); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// copyObjects 复制选区并返回新对象标识，复用字体和图片资源
// 入参: args 页码、对象标识列表和位移
// 返回: any 文档信息, error 错误信息
func copyObjects(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	objects, err := currentEditor.Objects(args[0].Int(), stringsFromJS(args[1]))
	if err != nil {
		return nil, err
	}
	return copyEditorObjects(args[0].Int(), objects, args[2].Float(), args[3].Float())
}

// captureObjects 保存独立选区快照，不修改文档或历史。
// 入参: args 页面索引、对象标识数组和剪贴板标识
// 返回: any 空结果, error 错误信息
func captureObjects(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	objects, err := currentEditor.Objects(args[0].Int(), stringsFromJS(args[1]))
	if err != nil {
		return nil, err
	}
	copiedObjects = &editorClipboard{args[2].String(), objects}
	return nil, nil
}

// pasteObjects 将当前文档的对象快照粘贴到目标页。
// 入参: args 目标页、剪贴板标识和横纵位移
// 返回: any 文档信息及新选区, error 错误信息
func pasteObjects(args []js.Value) (any, error) {
	if currentEditor == nil || copiedObjects == nil || copiedObjects.token != args[1].String() {
		return nil, fmt.Errorf("object clipboard is no longer available")
	}
	return copyEditorObjects(args[0].Int(), copiedObjects.objects, args[2].Float(), args[3].Float())
}

// copyEditorObjects 复制快照并更新预览，返回新对象标识。
// 入参: page 目标页, objects 对象快照, dx、dy 毫米位移
// 返回: any 文档信息及新选区, error 错误信息
func copyEditorObjects(page int, objects []ofdgo.GraphicObject, dx, dy float64) (any, error) {
	ids, err := currentEditor.CopyObjects(page, objects, dx, dy)
	if err != nil {
		return nil, err
	}
	if len(ids) == 0 {
		return editorSummary(), nil
	}
	info, err := previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
	return editorSelectionInfo{info, ids}, err
}

// orderObjects 调整选区的绘制顺序
// 入参: args 页码、对象标识列表和层级动作
// 返回: any 文档信息, error 错误信息
func orderObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.OrderObjects(args[0].Int(), stringsFromJS(args[1]), args[2].String())
	})
}

// distributeObjects 按指定轴等距分布选区。
// 入参: args 页面索引、对象标识数组和分布轴
// 返回: any 文档信息, error 错误信息
func distributeObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.DistributeObjects(args[0].Int(), stringsFromJS(args[1]), args[2].String())
	})
}

// deleteObject 删除创作画布中选中的对象
// 入参: args 页码和对象标识
// 返回: any 文档信息, error 错误信息
func deleteObject(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	if err := currentEditor.DeleteObject(args[0].Int(), args[1].String()); err != nil {
		return nil, err
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// changePage 管理创作文档的页面
// 入参: args 操作、页面索引及尺寸或目标索引
// 返回: any 文档信息和目标页面, error 错误信息
func changePage(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	index := args[1].Int()
	revision := currentEditor.Revision()
	var err error
	switch action := args[0].String(); action {
	case "add":
		index, err = currentEditor.AddPage(args[2].Float(), args[3].Float())
	case "copy":
		index, err = currentEditor.CopyPage(index)
	case "delete":
		if currentEditor.PageCount() == 1 {
			return nil, fmt.Errorf("the document must contain at least one page")
		}
		err = currentEditor.DeletePage(index)
		index = min(index, currentEditor.PageCount()-1)
	case "move":
		target := args[2].Int()
		err = currentEditor.MovePage(index, target)
		index = target
	case "resize":
		err = currentEditor.ResizePage(index, args[2].Float(), args[3].Float())
	default:
		return nil, fmt.Errorf("unsupported page action %q", action)
	}
	if err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorPageInfo{editorSummary(), index}, nil
	}
	info, err := previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
	if err != nil {
		return nil, err
	}
	return editorPageInfo{info, index}, nil
}

// createDocument 新建单页文档
// 入参: args 标题、纸张宽高和注解设置
// 返回: any 文档信息, error 错误信息
func createDocument(args []js.Value) (any, error) {
	editor := ofdgo.NewEditor()
	editor.Info.Title = args[0].String()
	if _, err := editor.AddPage(args[1].Float(), args[2].Float()); err != nil {
		return nil, err
	}
	editor.SetHistoryLimit(100)
	return previewEditor(editor, args[3].Bool())
}

// editDocument 将已打开文档接入编辑器，沿用页面、资源及字体配置。
// 入参: args 浏览器参数
// 返回: any 编辑状态, error 错误信息
func editDocument(args []js.Value) (any, error) {
	if currentSession == nil {
		return nil, fmt.Errorf("ofd document is not opened")
	}
	if currentEditor != nil {
		return editorSummary(), nil
	}
	editor, err := currentSession.Reader.Editor()
	if err != nil {
		return nil, err
	}
	editor.SetHistoryLimit(100)
	return previewEditor(editor, currentSession.Renderer.RenderAnnotations)
}

// previewEditor 通过内存快照更新预览，不生成中间压缩包
// 入参: editor 编辑文档, annotations 是否显示注解
// 返回: editorInfo 文档信息, error 错误信息
func previewEditor(editor *ofdgo.Editor, annotations bool) (editorInfo, error) {
	reader, err := editor.Reader()
	if err != nil {
		return editorInfo{}, err
	}
	session, err := newSession(reader, OpenOptions{RenderAnnotations: annotations})
	if err != nil {
		return editorInfo{}, err
	}
	if currentSession != nil {
		if currentSession.fontFS != nil {
			session.fontFS = currentSession.fontFS
			session.Renderer.SetFontFS(session.fontFS)
		}
		_ = currentSession.Close()
	}
	currentSession = session
	if currentEditor != editor {
		copiedObjects = nil
	}
	currentEditor = editor
	return editorSummary(), nil
}

// updateText 修改文字，null内容保留定位且允许替换字体，null字体数据和颜色沿用对象属性
// 入参: args 页码、对象标识、内容、字体数据、字号和颜色
// 返回: any 文档信息, error 错误信息
func updateText(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	page, id := args[0].Int(), args[1].String()
	object, err := currentEditor.Object(page, id)
	if err != nil {
		return nil, err
	}
	if object.Type != "TextObject" {
		return nil, fmt.Errorf("object %q is not text", id)
	}
	if !args[3].IsNull() {
		data, err := bytesFromJS(args[3])
		if err != nil {
			return nil, err
		}
		object.TextObject.Font, err = currentEditor.AddFont(FontFile{Data: data}, 0)
		if err != nil {
			return nil, err
		}
	}
	if !args[2].IsNull() {
		object.TextObject.Size = args[4].Float()
		_, layout := object.TextObject.TextLayout()
		if err := currentEditor.LayoutText(&object.TextObject, args[2].String(), layout); err != nil {
			return nil, err
		}
	}
	if !args[5].IsNull() {
		if err := setTextColor(&object.TextObject, args[5].String()); err != nil {
			return nil, err
		}
	}
	revision := currentEditor.Revision()
	if err := currentEditor.UpdateObject(page, id, object); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// setTextColor 将浏览器RGB色值写入文字对象，保留颜色透明度
// 入参: object 文字对象, value 十六进制色值
// 返回: error 错误信息
func setTextColor(object *ofdgo.TextObject, value string) error {
	if object.FillColor == nil {
		object.FillColor = &ofdgo.FillColor{}
	}
	return setEditorColor(object.FillColor, value)
}

// setEditorColor 写入浏览器RGB色值，保留其他颜色属性
// 入参: color 颜色, value 十六进制色值
// 返回: error 错误信息
func setEditorColor(color *ofdgo.FillColor, value string) error {
	if len(value) != 7 || value[0] != '#' {
		return fmt.Errorf("invalid RGB color %q", value)
	}
	rgb, err := hex.DecodeString(value[1:])
	if err != nil {
		return err
	}
	color.Value = fmt.Sprintf("%d %d %d", rgb[0], rgb[1], rgb[2])
	return nil
}

// editorColorHex 将创作对象的RGB颜色转换为浏览器色值
// 入参: color 颜色
// 返回: string 十六进制色值
func editorColorHex(color *ofdgo.FillColor) string {
	var r, g, b int
	if color != nil {
		fmt.Sscan(color.Value, &r, &g, &b)
	}
	return fmt.Sprintf("#%02x%02x%02x", r, g, b)
}

// editorPathScale 获取路径线宽的页面缩放比例
// 入参: object 路径对象
// 返回: float64 缩放比例
func editorPathScale(object ofdgo.PathObject) float64 {
	m := ofdgo.NewMatrix(object.CTM)
	x, y := m.Transform(0, 0)
	ax, ay := m.Transform(1, 0)
	bx, by := m.Transform(0, 1)
	return math.Sqrt(math.Abs((ax-x)*(by-y) - (ay-y)*(bx-x)))
}

// setPathStyle 应用图形填充、描边和线宽
// 入参: object 路径对象, args 填充开关及色值、描边开关及色值、线宽
// 返回: error 错误信息
func setPathStyle(object *ofdgo.PathObject, args []js.Value) error {
	fill, stroke, width := args[0].Bool(), args[2].Bool(), args[4].Float()
	if kind, _ := object.Shape(); kind == ofdgo.ShapeLine {
		fill, stroke = false, true
	}
	if !fill && !stroke {
		return fmt.Errorf("fill or stroke must be enabled")
	}
	if width <= 0 || math.IsNaN(width) || math.IsInf(width, 0) {
		return fmt.Errorf("line width must be positive and finite")
	}
	object.Fill, object.Stroke = &fill, &stroke
	if scale := editorPathScale(*object); width != object.LineWidth*scale {
		object.LineWidth = width / scale
	}
	if object.FillColor == nil {
		object.FillColor = &ofdgo.FillColor{}
	}
	if object.StrokeColor == nil {
		object.StrokeColor = &ofdgo.StrokeColor{}
	}
	if err := setEditorColor(object.FillColor, args[1].String()); err != nil {
		return err
	}
	return setEditorColor((*ofdgo.FillColor)(object.StrokeColor), args[3].String())
}

// insertShape 创建标准路径图形
// 入参: args 页码、图形类型、范围和绘制样式
// 返回: any 文档信息, error 错误信息
func insertShape(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	path, err := ofdgo.NewShape(ofdgo.ShapeKind(args[1].String()), ofdgo.Box{X: args[2].Float(), Y: args[3].Float(), W: args[4].Float(), H: args[5].Float()})
	if err != nil {
		return nil, err
	}
	if err := setPathStyle(&path, args[6:]); err != nil {
		return nil, err
	}
	if _, err := currentEditor.AddObject(args[0].Int(), ofdgo.GraphicObject{Type: "PathObject", PathObject: path}); err != nil {
		return nil, err
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// updatePathStyle 更新选中路径的绘制样式
// 入参: args 页码、对象标识和绘制样式
// 返回: any 文档信息, error 错误信息
func updatePathStyle(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	page, id := args[0].Int(), args[1].String()
	object, err := currentEditor.Object(page, id)
	if err != nil {
		return nil, err
	}
	if object.Type != "PathObject" {
		return nil, fmt.Errorf("object is not a path")
	}
	if err := setPathStyle(&object.PathObject, args[2:]); err != nil {
		return nil, err
	}
	revision := currentEditor.Revision()
	if err := currentEditor.UpdateObject(page, id, object); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// insertText 使用选定字体创建文字对象
// 入参: args 页码、内容、字体数据、横纵坐标、字号、颜色、框宽、折行、对齐、行距和字距
// 返回: any 文档信息, error 错误信息
func insertText(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	data, err := bytesFromJS(args[2])
	if err != nil {
		return nil, err
	}
	fontID, err := currentEditor.AddFont(FontFile{Data: data}, 0)
	if err != nil {
		return nil, err
	}
	page := args[0].Int()
	content, err := currentSession.pageContent(page)
	if err != nil {
		return nil, err
	}
	box, err := currentSession.pageBox(page, content)
	if err != nil {
		return nil, err
	}
	x, y := args[3].Float(), args[4].Float()
	width := args[7].Float()
	if width == 0 {
		width = 80
	}
	box = ofdgo.Box{X: x, Y: y, W: math.Min(width, box.W-x), H: box.H - y}
	object := ofdgo.GraphicObject{Type: "TextObject", TextObject: ofdgo.TextObject{
		Boundary: fmt.Sprintf("%g %g %g %g", box.X, box.Y, box.W, box.H),
		Font:     fontID, Size: args[5].Float(),
	}}
	if err := currentEditor.LayoutText(&object.TextObject, args[1].String(), ofdgo.TextLayout{Wrap: args[8].Bool(), Align: args[9].String(), LineHeight: args[10].Float(), LetterSpacing: args[11].Float()}); err != nil {
		return nil, err
	}
	if err := setTextColor(&object.TextObject, args[6].String()); err != nil {
		return nil, err
	}
	if _, err := currentEditor.AddObject(page, object); err != nil {
		return nil, err
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// layoutText 调整文字框和段落排版，保留软换行前的原文。
// 入参: args 页码、对象标识、本地左侧偏移、宽度、折行、对齐、行距和字距
// 返回: any 文档信息, error 错误信息
func layoutText(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	page, id := args[0].Int(), args[1].String()
	object, err := currentEditor.Object(page, id)
	if err != nil {
		return nil, err
	}
	if object.Type != "TextObject" {
		return nil, fmt.Errorf("object is not text")
	}
	if !args[2].IsNull() {
		object.TextObject, err = object.TextObject.ResizeTextFrame(args[2].Float(), args[3].Float())
		if err != nil {
			return nil, err
		}
	}
	value, _ := object.TextObject.TextLayout()
	if err := currentEditor.LayoutText(&object.TextObject, value, ofdgo.TextLayout{Wrap: args[4].Bool(), Align: args[5].String(), LineHeight: args[6].Float(), LetterSpacing: args[7].Float()}); err != nil {
		return nil, err
	}
	revision := currentEditor.Revision()
	if err := currentEditor.UpdateObject(page, id, object); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// editorBox 将库层毫米边界传递给画布交互层。
// 入参: box 毫米坐标中的矩形范围
// 返回: map[string]any 可直接传递给JavaScript的横纵坐标和宽高
func editorBox(box ofdgo.Box) map[string]any {
	return map[string]any{"x": box.X, "y": box.Y, "width": box.W, "height": box.H}
}

// editorMatrix 将标准CTM转换为浏览器仿射矩阵分量。
// 入参: matrix 库层仿射矩阵
// 返回: []any 可直接传递给JavaScript的a、b、c、d、e、f分量，位移单位为毫米
func editorMatrix(matrix ofdgo.Matrix) []any {
	x, y := matrix.Transform(0, 0)
	ax, ay := matrix.Transform(1, 0)
	bx, by := matrix.Transform(0, 1)
	return []any{ax - x, ay - y, bx - x, by - y, x, y}
}

// rotateObjects 旋转同页选区，通用几何与历史记录由库负责。
// 入参: args 页面索引、对象标识数组和顺时针角度
// 返回: any 文档信息, error 错误信息
func rotateObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.RotateObjects(args[0].Int(), stringsFromJS(args[1]), args[2].Int())
	})
}

// flipObjects 镜像同页选区。
// 入参: args 页面索引、对象标识数组和镜像轴
// 返回: any 文档信息, error 错误信息
func flipObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.FlipObjects(args[0].Int(), stringsFromJS(args[1]), args[2].String())
	})
}

// cropImage 设置图片裁剪范围，保留原始图片数据。
// 入参: args 页面索引、对象标识及页面毫米坐标中的横纵坐标和宽高
// 返回: any 文档信息, error 错误信息
func cropImage(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.CropImage(args[0].Int(), args[1].String(), ofdgo.Box{X: args[2].Float(), Y: args[3].Float(), W: args[4].Float(), H: args[5].Float()})
	})
}

// fitImage 按原始比例适应或填充图片框。
// 入参: args 页面索引、对象标识和适应方式
// 返回: any 文档信息, error 错误信息
func fitImage(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.FitImage(args[0].Int(), args[1].String(), args[2].String())
	})
}

// previewImage 在页面副本中显示指定图片的完整内容，不改变正文、历史或缓存。
// 入参: args 页面索引和图片对象标识
// 返回: any 页面SVG和分离的图片资源, error 错误信息
func previewImage(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	page, err := currentEditor.Page(args[0].Int())
	if err != nil {
		return nil, err
	}
	id := args[1].String()
	found := false
	for i := range page.Content.Layer {
		for j := range page.Content.Layer[i].Objects {
			object := &page.Content.Layer[i].Objects[j]
			if object.Type == "ImageObject" && object.ImageObject.ID == id {
				object.ImageObject.Clips = nil
				found = true
			}
		}
	}
	if !found {
		return nil, fmt.Errorf("image object %q not found", id)
	}
	var out bytes.Buffer
	resources, err := currentSession.Renderer.RenderToSVGWithResources(page, &out)
	if err != nil {
		return nil, err
	}
	return successResult(map[string]any{"svg": out.String(), "images": svgImagesToJS(resources.Images)}), nil
}

// svgImagesToJS 将图片资源以二进制数组传给前端，不使用base64。
// 入参: images SVG引用的图片资源
// 返回: []any 图片标识、类型和数据
func svgImagesToJS(images []ofdgo.SVGImage) []any {
	items := make([]any, len(images))
	for i, image := range images {
		items[i] = map[string]any{"name": image.Name, "mime": image.MIME, "bytes": bytesToJS(image.Data)}
	}
	return items
}

// transformObjects 统一移动或缩放选区，生成一次撤销记录。
// 入参: args 页面索引、对象标识数组、横纵位移和正缩放比例
// 返回: any 文档信息, error 错误信息
func transformObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.TransformObjects(args[0].Int(), stringsFromJS(args[1]), args[2].Float(), args[3].Float(), args[4].Float())
	})
}

// alignObjects 对齐选区中的对象。
// 入参: args 页面索引、对象标识数组和对齐方式
// 返回: any 文档信息, error 错误信息
func alignObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.AlignObjects(args[0].Int(), stringsFromJS(args[1]), args[2].String())
	})
}

// deleteObjects 一次删除选区中的对象。
// 入参: args 页面索引和对象标识数组
// 返回: any 文档信息, error 错误信息
func deleteObjects(args []js.Value) (any, error) {
	return changeObjects(func() error {
		return currentEditor.DeleteObjects(args[0].Int(), stringsFromJS(args[1]))
	})
}

// changeObjects 提交库层批量操作，无修改时复用当前预览。
// 入参: apply 待执行的编辑操作
// 返回: any 文档信息, error 错误信息
func changeObjects(apply func() error) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	revision := currentEditor.Revision()
	if err := apply(); err != nil {
		return nil, err
	}
	if currentEditor.Revision() == revision {
		return editorSummary(), nil
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// insertImage 按原始比例创建图片对象
// 入参: args 页码、图片数据、横纵坐标和宽度
// 返回: any 文档信息, error 错误信息
func insertImage(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	data, err := bytesFromJS(args[1])
	if err != nil {
		return nil, err
	}
	resourceID, err := currentEditor.AddImage(data)
	if err != nil {
		return nil, err
	}
	config, _, err := image.DecodeConfig(bytes.NewReader(data))
	if err != nil {
		return nil, err
	}
	width := args[4].Float()
	box := ofdgo.Box{X: args[2].Float(), Y: args[3].Float(), W: width, H: width * float64(config.Height) / float64(config.Width)}
	content, err := currentSession.pageContent(args[0].Int())
	if err != nil {
		return nil, err
	}
	pageBox, err := currentSession.pageBox(args[0].Int(), content)
	if err != nil {
		return nil, err
	}
	if height := pageBox.H - box.Y*2; box.H > height {
		box.W *= height / box.H
		box.H = height
	}
	object := ofdgo.GraphicObject{Type: "ImageObject", ImageObject: ofdgo.ImageObject{
		ResourceID: resourceID, Boundary: fmt.Sprintf("%g %g %g %g", box.X, box.Y, box.W, box.H),
	}}
	if _, err := currentEditor.AddObject(args[0].Int(), object); err != nil {
		return nil, err
	}
	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
}

// saveDocument 分块写出当前编辑文档
// 入参: args 数据写出回调
// 返回: any 保存结果, error 错误信息
func saveDocument(args []js.Value) (any, error) {
	if currentEditor == nil {
		return nil, fmt.Errorf("no document is being edited")
	}
	writer := bufio.NewWriterSize(exportWriter{write: args[0]}, 1<<20)
	if _, err := currentEditor.WriteTo(writer); err != nil {
		return nil, err
	}
	if err := writer.Flush(); err != nil {
		return nil, err
	}
	return successResult(map[string]any{"mime": "application/ofd", "label": "OFD"}), nil
}