Agent-System-Backend/internal/docgen/docgen.go

// Package docgen 把 Markdown 源文转换为带排版样式的 Word（.docx）文档。
//
// 定位（正式交付物直接可交）：模型只需产出 Markdown，本包负责把
// "#/##/### 标题、有序/无序列表、任务项、GFM 表格、引用块、代码块、
// 粗体/斜体/行内代码/删除线/超链接" 渲染成真正的 Word 样式——
// Heading1-4 大纲层级、底纹表头表格、numbering.xml 真编号列表、
// 引用左线、等宽底纹代码段。打开即是有排版的正式文档，不是纯文本。
//
// 零第三方依赖：archive/zip + 手写 OOXML（WordprocessingML）。
// 兼容性约束：产物必须能被本仓 ingest.parseDocx 回读（pStyle 含
// Heading1-4、表格 tr/tc 结构），且前端 mammoth 预览可还原标题层级。
package docgen

import (
	"archive/zip"
	"bytes"
	"fmt"
	"strings"
)

// Build 生成 docx 字节。title 为文档标题；为空时取首个标题块，再无则不带 Title 段。
func Build(title, markdown string) ([]byte, error) {
	doc := parseMarkdown(markdown)
	title = strings.TrimSpace(title)
	if title == "" {
		title = doc.firstHeading()
	}

	var body strings.Builder
	body.WriteString(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>` + "\n")
	body.WriteString(`<w:document xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><w:body>`)
	if title != "" {
		body.WriteString(doc.paragraph("Title", []run{{text: title}}))
	}
	for i := range doc.blocks {
		doc.writeBlock(&body, i)
	}
	// sectPr：A4 + 中文文档常规页边距（上下 2.54cm、左右 3.18cm，twips）。
	body.WriteString(`<w:sectPr><w:pgSz w:w="11906" w:h="16838"/><w:pgMar w:top="1440" w:right="1800" w:bottom="1440" w:left="1800" w:header="851" w:footer="992" w:gutter="0"/></w:sectPr>`)
	body.WriteString("</w:body></w:document>")

	files := []struct{ name, data string }{
		{"[Content_Types].xml", contentTypesXML()},
		{"_rels/.rels", rootRelsXML()},
		{"word/document.xml", body.String()},
		{"word/_rels/document.xml.rels", doc.relsXML()},
		{"word/styles.xml", stylesXML()},
		{"word/numbering.xml", numberingXML()},
		{"docProps/core.xml", coreXML(title)},
		{"docProps/app.xml", appXML()},
	}
	var buf bytes.Buffer
	zw := zip.NewWriter(&buf)
	for _, f := range files {
		w, err := zw.Create(f.name)
		if err != nil {
			return nil, fmt.Errorf("docgen: create %s: %w", f.name, err)
		}
		if _, err := w.Write([]byte(f.data)); err != nil {
			return nil, fmt.Errorf("docgen: write %s: %w", f.name, err)
		}
	}
	if err := zw.Close(); err != nil {
		return nil, fmt.Errorf("docgen: close zip: %w", err)
	}
	return buf.Bytes(), nil
}

// SuggestName 由标题给一个人类可读的 .docx 文件名（调用方可不用）。
func SuggestName(title string) string {
	s := strings.Map(func(r rune) rune {
		switch r {
		case '/', '\\', ':', '*', '?', '"', '<', '>', '|', '\n', '\r', '\t':
			return -1
		}
		return r
	}, strings.TrimSpace(title))
	if r := []rune(s); len(r) > 60 {
		s = string(r[:60])
	}
	if s == "" {
		s = "文档"
	}
	return s + ".docx"
}

// ---- Markdown 块级解析 ----

type blockKind int

const (
	bPara blockKind = iota
	bHeading
	bList
	bTable
	bCode
	bQuote
	bHR
)

type block struct {
	kind      blockKind
	level     int      // 标题级别 1-6
	lines     []string // 段落/引用/代码的原始行
	items     []listItem
	rows      [][]string
	align     []string
	hasHeader bool
}

type listItem struct {
	text    string
	level   int // 0 起
	ordered bool
	checked *bool
}

// document 承载解析结果与生成期状态（超链接收集、列表编号序列分配）。
type document struct {
	blocks     []block
	hyperlinks []string
	listSeqs   int
}

func (d *document) firstHeading() string {
	for _, b := range d.blocks {
		if b.kind == bHeading {
			return strings.Join(b.lines, " ")
		}
	}
	return ""
}

func parseMarkdown(src string) *document {
	lines := strings.Split(strings.ReplaceAll(src, "\r\n", "\n"), "\n")
	d := &document{}
	i := 0
	for i < len(lines) {
		line := lines[i]
		trimmed := strings.TrimSpace(line)
		switch {
		case trimmed == "":
			i++
		case strings.HasPrefix(trimmed, "```") || strings.HasPrefix(trimmed, "~~~"):
			i = d.parseCode(lines, i)
		case isHR(trimmed):
			d.blocks = append(d.blocks, block{kind: bHR})
			i++
		case strings.HasPrefix(trimmed, "#"):
			if lvl, text, ok := parseHeading(trimmed); ok {
				d.blocks = append(d.blocks, block{kind: bHeading, level: lvl, lines: []string{text}})
				i++
			} else {
				i = d.parsePara(lines, i)
			}
		case isTableStart(lines, i):
			i = d.parseTable(lines, i)
		case isListLine(trimmed):
			i = d.parseList(lines, i)
		case strings.HasPrefix(trimmed, ">"):
			i = d.parseQuote(lines, i)
		default:
			i = d.parsePara(lines, i)
		}
	}
	return d
}

func isHR(s string) bool {
	if len(s) < 3 {
		return false
	}
	for _, ch := range []byte{'-', '*', '_'} {
		if s[0] == ch {
			return strings.TrimSpace(strings.ReplaceAll(s, string(ch), "")) == ""
		}
	}
	return false
}

func parseHeading(s string) (int, string, bool) {
	n := 0
	for n < len(s) && s[n] == '#' {
		n++
	}
	if n == 0 || n > 6 || n >= len(s) || s[n] != ' ' {
		return 0, "", false
	}
	return n, strings.TrimSpace(s[n+1:]), true
}

func (d *document) parseCode(lines []string, i int) int {
	mark := strings.TrimSpace(lines[i])[:3]
	var body []string
	j := i + 1
	for ; j < len(lines); j++ {
		t := strings.TrimSpace(lines[j])
		if strings.HasPrefix(t, mark) && strings.TrimLeft(t, mark) == "" {
			j++
			break
		}
		body = append(body, lines[j])
	}
	d.blocks = append(d.blocks, block{kind: bCode, lines: body})
	return j
}

func (d *document) parseQuote(lines []string, i int) int {
	var body []string
	for ; i < len(lines); i++ {
		t := strings.TrimSpace(lines[i])
		if !strings.HasPrefix(t, ">") {
			break
		}
		body = append(body, strings.TrimPrefix(strings.TrimPrefix(t, ">"), " "))
	}
	// 引用内按空行切分多段。
	var cur []string
	for _, l := range body {
		if strings.TrimSpace(l) == "" {
			if len(cur) > 0 {
				d.blocks = append(d.blocks, block{kind: bQuote, lines: cur})
				cur = nil
			}
			continue
		}
		cur = append(cur, l)
	}
	if len(cur) > 0 {
		d.blocks = append(d.blocks, block{kind: bQuote, lines: cur})
	}
	return i
}

func (d *document) parsePara(lines []string, i int) int {
	var body []string
	for ; i < len(lines); i++ {
		t := strings.TrimSpace(lines[i])
		if t == "" || strings.HasPrefix(t, "#") || strings.HasPrefix(t, ">") ||
			strings.HasPrefix(t, "```") || strings.HasPrefix(t, "~~~") ||
			isListLine(t) || isTableStart(lines, i) || isHR(t) {
			break
		}
		body = append(body, lines[i])
	}
	if len(body) == 0 { // 防御：单行无法归块时按原文吃掉一行，避免死循环。
		body = []string{lines[i]}
		i++
	}
	d.blocks = append(d.blocks, block{kind: bPara, lines: body})
	return i
}

func isListLine(s string) bool {
	_, _, _, ok := splitListMarker(s)
	return ok
}

// splitListMarker 解析列表行：缩进层级（每 2 空格一级，封顶 3）、是否有序、
// 去掉标记后的文本。
func splitListMarker(s string) (level int, ordered bool, text string, ok bool) {
	n := 0
	for n < len(s) && (s[n] == ' ' || s[n] == '\t') {
		n++
	}
	level = n / 2
	if level > 3 {
		level = 3
	}
	rest := s[n:]
	for _, m := range []string{"- ", "* ", "+ "} {
		if strings.HasPrefix(rest, m) {
			return level, false, rest[2:], true
		}
	}
	k := 0
	for k < len(rest) && rest[k] >= '0' && rest[k] <= '9' {
		k++
	}
	if k > 0 && k <= 4 && k < len(rest) && (rest[k] == '.' || rest[k] == ')') && k+1 < len(rest) && rest[k+1] == ' ' {
		return level, true, rest[k+2:], true
	}
	return 0, false, s, false
}

func (d *document) parseList(lines []string, i int) int {
	var items []listItem
	for ; i < len(lines); i++ {
		t := strings.TrimSpace(lines[i])
		if t == "" {
			break
		}
		level, ordered, text, ok := splitListMarker(t)
		if !ok {
			break
		}
		it := listItem{level: level, ordered: ordered}
		if !ordered {
			switch {
			case strings.HasPrefix(text, "[ ] "), text == "[ ]":
				it.checked = boolPtr(false)
				text = strings.TrimSpace(strings.TrimPrefix(text, "[ ]"))
			case strings.HasPrefix(text, "[x] "), strings.HasPrefix(text, "[X] "), text == "[x]", text == "[X]":
				it.checked = boolPtr(true)
				text = strings.TrimSpace(strings.TrimPrefix(strings.TrimPrefix(text, "[x] "), "[X] "))
			}
		}
		it.text = strings.TrimSpace(text)
		items = append(items, it)
	}
	d.blocks = append(d.blocks, block{kind: bList, items: items})
	return i
}

// isTableStart：以 | 开头或结尾的行，或「含 | 且下一行是分隔行」——后者覆盖
// 无边框管道写法，同时避免把正文里含 | 的普通句子误判成表格。
func isTableStart(lines []string, i int) bool {
	t := strings.TrimSpace(lines[i])
	if !strings.Contains(t, "|") {
		return false
	}
	if strings.HasPrefix(t, "|") || strings.HasSuffix(t, "|") {
		return true
	}
	return i+1 < len(lines) && isTableSeparator(strings.TrimSpace(lines[i+1]))
}

func isTableSeparator(s string) bool {
	core := strings.ReplaceAll(strings.ReplaceAll(s, "|", ""), " ", "")
	if core == "" {
		return false
	}
	for _, ch := range core {
		if ch != '-' && ch != ':' {
			return false
		}
	}
	return true
}

func (d *document) parseTable(lines []string, i int) int {
	var rows [][]string
	var align []string
	hasHeader := false
	for ; i < len(lines); i++ {
		t := strings.TrimSpace(lines[i])
		if t == "" || !strings.Contains(t, "|") {
			break
		}
		if isTableSeparator(t) {
			align = parseTableAlign(t)
			hasHeader = true
			continue
		}
		rows = append(rows, splitTableRow(t))
	}
	if len(rows) == 0 {
		return i + 1 // 只有分隔行等异常输入：吃掉一行防死循环。
	}
	d.blocks = append(d.blocks, block{kind: bTable, rows: rows, align: align, hasHeader: hasHeader})
	return i
}

func parseTableAlign(sep string) []string {
	cells := splitTableRow(sep)
	out := make([]string, len(cells))
	for i, c := range cells {
		c = strings.TrimSpace(c)
		left := strings.HasPrefix(c, ":")
		right := strings.HasSuffix(c, ":")
		switch {
		case left && right:
			out[i] = "center"
		case right:
			out[i] = "right"
		default:
			out[i] = "left"
		}
	}
	return out
}

func splitTableRow(s string) []string {
	s = strings.TrimSpace(s)
	s = strings.TrimPrefix(s, "|")
	s = strings.TrimSuffix(s, "|")
	parts := strings.Split(s, "|")
	out := make([]string, len(parts))
	for i, p := range parts {
		out[i] = strings.TrimSpace(p)
	}
	return out
}

func boolPtr(b bool) *bool { return &b }

// ---- 行内解析：**粗**、*斜*、`码`、~~删~~、[文](链) ----

type run struct {
	text   string
	bold   bool
	italic bool
	code   bool
	strike bool
	link   string
}

func (d *document) parseInline(s string) []run {
	var runs []run
	i, start := 0, 0
	flush := func(end int) {
		if end > start {
			runs = append(runs, run{text: s[start:end]})
		}
	}
	for i < len(s) {
		c := s[i]
		switch {
		case c == '\\':
			flush(i)
			if i+1 < len(s) {
				runs = append(runs, run{text: string(s[i+1])})
			}
			i += 2
			start = i
		case c == '`':
			if end := strings.IndexByte(s[i+1:], '`'); end >= 0 {
				flush(i)
				runs = append(runs, run{text: s[i+1 : i+1+end], code: true})
				i += end + 2
				start = i
			} else {
				i++
			}
		case c == '*' && i+1 < len(s) && s[i+1] == '*':
			if end, ok := findClose(s, i+2, "**"); ok {
				flush(i)
				runs = append(runs, mapAll(d.parseInline(s[i+2:end]), func(r run) run { r.bold = true; return r })...)
				i = end + 2
				start = i
			} else {
				i++
			}
		case c == '~' && i+1 < len(s) && s[i+1] == '~':
			if end, ok := findClose(s, i+2, "~~"); ok {
				flush(i)
				runs = append(runs, mapAll(d.parseInline(s[i+2:end]), func(r run) run { r.strike = true; return r })...)
				i = end + 2
				start = i
			} else {
				i++
			}
		case c == '*' || c == '_':
			if end, ok := findClose(s, i+1, string(c)); ok && strings.TrimSpace(s[i+1:end]) != "" {
				flush(i)
				runs = append(runs, mapAll(d.parseInline(s[i+1:end]), func(r run) run { r.italic = true; return r })...)
				i = end + 1
				start = i
			} else {
				i++
			}
		case c == '[':
			if text, href, next, ok := parseLink(s, i); ok {
				flush(i)
				runs = append(runs, run{text: text, link: href})
				d.hyperlinks = appendLink(d.hyperlinks, href)
				i = next
				start = i
			} else {
				i++
			}
		default:
			i++
		}
	}
	flush(len(s))
	return runs
}

// parseLink 解析 [text](href)：href 需带协议/锚点/mailto，防把普通方括号误判。
func parseLink(s string, i int) (text, href string, next int, ok bool) {
	close := strings.IndexByte(s[i:], ']')
	if close <= 0 {
		return "", "", 0, false
	}
	after := i + close + 1
	if after >= len(s) || s[after] != '(' {
		return "", "", 0, false
	}
	pclose := strings.IndexByte(s[after:], ')')
	if pclose <= 0 {
		return "", "", 0, false
	}
	h := s[after+1 : after+pclose]
	if !strings.Contains(h, "://") && !strings.HasPrefix(h, "#") && !strings.HasPrefix(h, "mailto:") {
		return "", "", 0, false
	}
	return s[i+1 : i+close], h, after + pclose + 1, true
}

func mapAll(rs []run, f func(run) run) []run {
	out := make([]run, len(rs))
	for i, r := range rs {
		out[i] = f(r)
	}
	return out
}

func findClose(s string, from int, mark string) (int, bool) {
	idx := strings.Index(s[from:], mark)
	if idx <= 0 { // 0 = 空内容，-1 = 未闭合。
		return 0, false
	}
	return from + idx, true
}

func appendLink(list []string, href string) []string {
	for _, h := range list {
		if h == href {
			return list
		}
	}
	return append(list, href)
}

// ---- OOXML 生成 ----

// paragraph 渲染一个段落：style 为样式 ID，extra 追加进 pPr（如 numPr）。
func (d *document) paragraph(style string, runs []run, extra ...string) string {
	var sb strings.Builder
	sb.WriteString("<w:p><w:pPr>")
	if style != "" {
		sb.WriteString(`<w:pStyle w:val="` + style + `"/>`)
	}
	for _, e := range extra {
		sb.WriteString(e)
	}
	sb.WriteString("</w:pPr>")
	for _, r := range runs {
		sb.WriteString(d.runXML(r))
	}
	sb.WriteString("</w:p>")
	return sb.String()
}

func (d *document) runsXML(runs []run) string {
	var sb strings.Builder
	for _, r := range runs {
		sb.WriteString(d.runXML(r))
	}
	return sb.String()
}

func (d *document) runXML(r run) string {
	if r.text == "" {
		return ""
	}
	var props []string
	if r.bold {
		props = append(props, "<w:b/><w:bCs/>")
	}
	if r.italic {
		props = append(props, "<w:i/><w:iCs/>")
	}
	if r.strike {
		props = append(props, "<w:strike/>")
	}
	if r.code {
		props = append(props, `<w:rFonts w:ascii="Consolas" w:hAnsi="Consolas"/>`)
	}
	if r.link != "" {
		rid := d.hyperlinkRID(r.link)
		return fmt.Sprintf(`<w:hyperlink r:id="%s"><w:r><w:rPr><w:rStyle w:val="Hyperlink"/>%s</w:rPr>%s</w:r></w:hyperlink>`,
			rid, strings.Join(props, ""), textRuns(r.text))
	}
	return "<w:r>" + rPr(props) + textRuns(r.text) + "</w:r>"
}

// textRuns 把文本渲染为 w:t；段内换行转 w:br（Word 段内不保留裸 \n）。
func textRuns(text string) string {
	var sb strings.Builder
	parts := strings.Split(text, "\n")
	for i, p := range parts {
		if i > 0 {
			sb.WriteString("<w:br/>")
		}
		if p != "" {
			sb.WriteString(`<w:t xml:space="preserve">` + esc(p) + `</w:t>`)
		}
	}
	return sb.String()
}

func rPr(props []string) string {
	if len(props) == 0 {
		return ""
	}
	return "<w:rPr>" + strings.Join(props, "") + "</w:rPr>"
}

func (d *document) hyperlinkRID(href string) string {
	for i, h := range d.hyperlinks {
		if h == href {
			return fmt.Sprintf("rIdH%d", i+1)
		}
	}
	return ""
}

// 列表编号分配：numbering.xml 预生成成对 num 实例——无序 1、3..52；有序
// 2（重启）、53..102（重启）。newListNumID 按序取用；超出预生成数回落
// 常驻 1/2（Word 容忍多列表共用编号，代价是有序编号延续）。
const (
	numPairBase     = 3
	numOrderedShift = 50
	numPairsTotal   = 50
	numFallbackBul  = 1
	numFallbackOrd  = 2
)

func (d *document) newListNumID(ordered bool) int {
	d.listSeqs++
	base := numPairBase + d.listSeqs - 1
	if base >= numPairBase+numPairsTotal {
		if ordered {
			return numFallbackOrd
		}
		return numFallbackBul
	}
	if ordered {
		return base + numOrderedShift
	}
	return base
}

func (d *document) writeBlock(sb *strings.Builder, i int) {
	b := &d.blocks[i]
	switch b.kind {
	case bHeading:
		lvl := b.level
		if lvl > 4 {
			lvl = 4
		}
		sb.WriteString(d.paragraph(fmt.Sprintf("Heading%d", lvl), d.parseInline(b.lines[0])))
	case bPara:
		sb.WriteString(d.paragraph("", d.parseInline(strings.Join(b.lines, "\n"))))
	case bQuote:
		for _, line := range b.lines {
			sb.WriteString(d.paragraph("Quote", d.parseInline(line)))
		}
	case bCode:
		for _, line := range b.lines {
			txt := line
			if txt == "" {
				txt = " "
			}
			sb.WriteString(d.paragraph("CodePara", []run{{text: txt}}))
		}
	case bHR:
		sb.WriteString(`<w:p><w:pPr><w:pBdr><w:bottom w:val="single" w:sz="6" w:space="1" w:color="BFBFBF"/></w:pBdr></w:pPr></w:p>`)
	case bList:
		numID := d.newListNumID(isOrdered(b.items))
		for _, it := range b.items {
			var runs []run
			if it.checked != nil {
				glyph := "☐"
				if *it.checked {
					glyph = "☑"
				}
				runs = append(runs, run{text: glyph + " "})
			}
			runs = append(runs, d.parseInline(it.text)...)
			sb.WriteString(d.paragraph("ListParagraph", runs,
				fmt.Sprintf(`<w:numPr><w:ilvl w:val="%d"/><w:numId w:val="%d"/></w:numPr>`, it.level, numID)))
		}
	case bTable:
		sb.WriteString(d.tableXML(b))
	}
}

func isOrdered(items []listItem) bool {
	for _, it := range items {
		if it.ordered {
			return true
		}
	}
	return false
}

func (d *document) tableXML(b *block) string {
	cols := 0
	for _, row := range b.rows {
		if len(row) > cols {
			cols = len(row)
		}
	}
	align := make([]string, cols)
	for i := range align {
		align[i] = "left"
		if i < len(b.align) {
			align[i] = b.align[i]
		}
	}

	var sb strings.Builder
	sb.WriteString(`<w:tbl><w:tblPr><w:tblW w:w="5000" w:type="pct"/><w:tblBorders>`)
	for _, edge := range []string{"top", "left", "bottom", "right", "insideH", "insideV"} {
		sb.WriteString(fmt.Sprintf(`<w:%s w:val="single" w:sz="4" w:space="0" w:color="BFBFBF"/>`, edge))
	}
	sb.WriteString(`</w:tblBorders><w:tblCellMar><w:top w:w="60" w:type="dxa"/><w:left w:w="108" w:type="dxa"/><w:bottom w:w="60" w:type="dxa"/><w:right w:w="108" w:type="dxa"/></w:tblCellMar></w:tblPr>`)
	for ri, row := range b.rows {
		header := b.hasHeader && ri == 0
		sb.WriteString("<w:tr>")
		if header {
			sb.WriteString(`<w:trPr><w:tblHeader/></w:trPr>`)
		}
		for ci := 0; ci < cols; ci++ {
			cell := ""
			if ci < len(row) {
				cell = row[ci]
			}
			var runs []run
			if header {
				runs = []run{{text: cell, bold: true}}
			} else {
				runs = d.parseInline(cell)
			}
			shd := ""
			if header {
				shd = `<w:shd w:val="clear" w:fill="EEF2F8"/>`
			}
			sb.WriteString(fmt.Sprintf(`<w:tc><w:tcPr>%s</w:tcPr><w:p><w:pPr><w:spacing w:before="20" w:after="20"/><w:jc w:val="%s"/></w:pPr>%s</w:p></w:tc>`,
				shd, align[ci], d.runsXML(runs)))
		}
		sb.WriteString("</w:tr>")
	}
	sb.WriteString("</w:tbl>")
	// 表后补一个近零高度空段：防相邻表格被 Word 合并。
	sb.WriteString(`<w:p><w:pPr><w:spacing w:after="0" w:line="240" w:lineRule="auto"/></w:pPr></w:p>`)
	return sb.String()
}

// ---- 包部件文件 ----

func esc(s string) string {
	var sb strings.Builder
	for _, r := range s {
		switch r {
		case '&':
			sb.WriteString("&amp;")
		case '<':
			sb.WriteString("&lt;")
		case '>':
			sb.WriteString("&gt;")
		case '"':
			sb.WriteString("&quot;")
		case '\'':
			sb.WriteString("&apos;")
		default:
			sb.WriteRune(r)
		}
	}
	return sb.String()
}

func contentTypesXML() string {
	return `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">
<Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>
<Default Extension="xml" ContentType="application/xml"/>
<Override PartName="/word/document.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml"/>
<Override PartName="/word/styles.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.styles+xml"/>
<Override PartName="/word/numbering.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.numbering+xml"/>
<Override PartName="/docProps/core.xml" ContentType="application/vnd.openxmlformats-package.core-properties+xml"/>
<Override PartName="/docProps/app.xml" ContentType="application/vnd.openxmlformats-officedocument.extended-properties+xml"/>
</Types>`
}

func rootRelsXML() string {
	return `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="word/document.xml"/>
<Relationship Id="rId2" Type="http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties" Target="docProps/core.xml"/>
<Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties" Target="docProps/app.xml"/>
</Relationships>`
}

func (d *document) relsXML() string {
	var sb strings.Builder
	sb.WriteString(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>` + "\n")
	sb.WriteString(`<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">`)
	sb.WriteString(`<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" Target="styles.xml"/>`)
	sb.WriteString(`<Relationship Id="rId2" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/numbering" Target="numbering.xml"/>`)
	for i, href := range d.hyperlinks {
		sb.WriteString(fmt.Sprintf(`<Relationship Id="rIdH%d" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink" Target="%s" TargetMode="External"/>`, i+1, esc(href)))
	}
	sb.WriteString(`</Relationships>`)
	return sb.String()
}

func stylesXML() string {
	return `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<w:styles xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">
<w:docDefaults><w:rPrDefault><w:rPr>
<w:rFonts w:ascii="Calibri" w:hAnsi="Calibri" w:eastAsia="等线" w:cs="Calibri"/>
<w:sz w:val="22"/><w:szCs w:val="22"/><w:lang w:val="en-US" w:eastAsia="zh-CN"/>
</w:rPr></w:rPrDefault><w:pPrDefault><w:pPr><w:spacing w:after="120" w:line="300" w:lineRule="auto"/></w:pPr></w:pPrDefault></w:docDefaults>
<w:style w:type="paragraph" w:default="1" w:styleId="Normal"><w:name w:val="Normal"/><w:qFormat/><w:pPr><w:spacing w:after="120" w:line="300" w:lineRule="auto"/></w:pPr></w:style>
<w:style w:type="paragraph" w:styleId="Title"><w:name w:val="Title"/><w:basedOn w:val="Normal"/><w:qFormat/>
<w:pPr><w:jc w:val="center"/><w:spacing w:before="120" w:after="360"/></w:pPr>
<w:rPr><w:b/><w:sz w:val="44"/><w:szCs w:val="44"/><w:color w:val="1F3864"/></w:rPr></w:style>
<w:style w:type="paragraph" w:styleId="Heading1"><w:name w:val="heading 1"/><w:basedOn w:val="Normal"/><w:next w:val="Normal"/><w:qFormat/>
<w:pPr><w:keepNext/><w:outlineLvl w:val="0"/><w:spacing w:before="320" w:after="160"/></w:pPr>
<w:rPr><w:b/><w:sz w:val="32"/><w:szCs w:val="32"/><w:color w:val="1F4E79"/></w:rPr></w:style>
<w:style w:type="paragraph" w:styleId="Heading2"><w:name w:val="heading 2"/><w:basedOn w:val="Normal"/><w:next w:val="Normal"/><w:qFormat/>
<w:pPr><w:keepNext/><w:outlineLvl w:val="1"/><w:spacing w:before="280" w:after="140"/></w:pPr>
<w:rPr><w:b/><w:sz w:val="28"/><w:szCs w:val="28"/><w:color w:val="2E74B5"/></w:rPr></w:style>
<w:style w:type="paragraph" w:styleId="Heading3"><w:name w:val="heading 3"/><w:basedOn w:val="Normal"/><w:next w:val="Normal"/><w:qFormat/>
<w:pPr><w:keepNext/><w:outlineLvl w:val="2"/><w:spacing w:before="240" w:after="120"/></w:pPr>
<w:rPr><w:b/><w:sz w:val="24"/><w:szCs w:val="24"/><w:color w:val="404040"/></w:rPr></w:style>
<w:style w:type="paragraph" w:styleId="Heading4"><w:name w:val="heading 4"/><w:basedOn w:val="Normal"/><w:next w:val="Normal"/><w:qFormat/>
<w:pPr><w:keepNext/><w:outlineLvl w:val="3"/><w:spacing w:before="200" w:after="100"/></w:pPr>
<w:rPr><w:b/><w:sz w:val="22"/><w:szCs w:val="22"/><w:color w:val="595959"/></w:rPr></w:style>
<w:style w:type="paragraph" w:styleId="ListParagraph"><w:name w:val="List Paragraph"/><w:basedOn w:val="Normal"/><w:qFormat/>
<w:pPr><w:contextualSpacing/></w:pPr></w:style>
<w:style w:type="paragraph" w:styleId="Quote"><w:name w:val="Quote"/><w:basedOn w:val="Normal"/><w:qFormat/>
<w:pPr><w:pBdr><w:left w:val="single" w:sz="18" w:space="4" w:color="4472C4"/></w:pBdr><w:ind w:left="360"/><w:spacing w:after="80"/></w:pPr>
<w:rPr><w:color w:val="595959"/></w:rPr></w:style>
<w:style w:type="paragraph" w:styleId="CodePara"><w:name w:val="Code Paragraph"/><w:basedOn w:val="Normal"/><w:qFormat/>
<w:pPr><w:shd w:val="clear" w:fill="F5F5F5"/><w:spacing w:after="0" w:line="264" w:lineRule="auto"/><w:ind w:left="240" w:right="240"/></w:pPr>
<w:rPr><w:rFonts w:ascii="Consolas" w:hAnsi="Consolas"/><w:sz w:val="19"/><w:szCs w:val="19"/></w:rPr></w:style>
<w:style w:type="character" w:styleId="Hyperlink"><w:name w:val="Hyperlink"/>
<w:rPr><w:color w:val="0563C1"/><w:u w:val="single"/></w:rPr></w:style>
</w:styles>`
}

// numberingXML：abstractNum 0（无序）/1（有序）+ 预生成成对 num 实例，
// 与 newListNumID 的分配方案对齐（见其注释）。
func numberingXML() string {
	var sb strings.Builder
	sb.WriteString(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>` + "\n")
	sb.WriteString(`<w:numbering xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">`)
	sb.WriteString(abstractNumXML(0, false))
	sb.WriteString(abstractNumXML(1, true))
	sb.WriteString(numXML(1, 0, false))
	sb.WriteString(numXML(2, 1, true))
	for i := 0; i < numPairsTotal; i++ {
		sb.WriteString(numXML(numPairBase+i, 0, false))
		sb.WriteString(numXML(numPairBase+i+numOrderedShift, 1, true))
	}
	sb.WriteString(`</w:numbering>`)
	return sb.String()
}

func abstractNumXML(aid int, ordered bool) string {
	var sb strings.Builder
	sb.WriteString(fmt.Sprintf(`<w:abstractNum w:abstractNumId="%d"><w:multiLevelType w:val="hybridMultilevel"/>`, aid))
	bullets := []string{"•", "◦", "▪", "·"}
	for lvl := 0; lvl < 4; lvl++ {
		if ordered {
			sb.WriteString(fmt.Sprintf(`<w:lvl w:ilvl="%d"><w:start w:val="1"/><w:numFmt w:val="decimal"/><w:lvlText w:val="%%%d."/><w:lvlJc w:val="left"/>`, lvl, lvl+1))
		} else {
			sb.WriteString(fmt.Sprintf(`<w:lvl w:ilvl="%d"><w:start w:val="1"/><w:numFmt w:val="bullet"/><w:lvlText w:val="%s"/><w:lvlJc w:val="left"/>`, lvl, bullets[lvl]))
		}
		sb.WriteString(fmt.Sprintf(`<w:pPr><w:ind w:left="%d" w:hanging="360"/></w:pPr></w:lvl>`, 720+lvl*420))
	}
	sb.WriteString(`</w:abstractNum>`)
	return sb.String()
}

func numXML(numID, abstractID int, restart bool) string {
	ov := ""
	if restart {
		ov = `<w:lvlOverride w:ilvl="0"><w:startOverride w:val="1"/></w:lvlOverride>`
	}
	return fmt.Sprintf(`<w:num w:numId="%d"><w:abstractNumId w:val="%d"/>%s</w:num>`, numID, abstractID, ov)
}

func coreXML(title string) string {
	return fmt.Sprintf(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<cp:coreProperties xmlns:cp="http://schemas.openxmlformats.org/package/2006/metadata/core-properties" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<dc:title>%s</dc:title><dc:creator>Agent-System</dc:creator><cp:lastModifiedBy>Agent-System</cp:lastModifiedBy>
</cp:coreProperties>`, esc(title))
}

func appXML() string {
	return `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Properties xmlns="http://schemas.openxmlformats.org/officeDocument/2006/extended-properties" xmlns:vt="http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes">
<Application>Agent-System docgen</Application>
</Properties>`
}