grimoir/pdf.go

package main

import (
	"bytes"
	"fmt"
	"math"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"time"
)

// === PDF генератор ===
//
// Два режима:
//   1. TTF mode: найден системный шрифт с кириллицей → встраиваем subset,
//      текст кодируем в UTF-16BE, используем Type0/CIDFont.
//   2. Fallback mode: шрифт не найден → встроенные PDF шрифты (Helvetica),
//      кириллица транслитерируется.

// A4 в pt
const (
	pageWidth  = 595.28
	pageHeight = 841.89
	marginL    = 60.0
	marginR    = 60.0
	marginT    = 60.0
	marginB    = 60.0
	textWidth  = pageWidth - marginL - marginR
)

// Размеры шрифтов
const (
	fontSizeBody  = 11.0
	fontSizeH1    = 22.0
	fontSizeH2    = 17.0
	fontSizeH3    = 14.0
	fontSizeH4    = 12.0
	fontSizeCode  = 9.5
	lineHeightMul = 1.4
)

// pdfColor — RGB 0.0–1.0
type pdfColor struct{ r, g, b float64 }

var (
	colorBlack    = pdfColor{0, 0, 0}
	colorDarkGray = pdfColor{0.2, 0.2, 0.2}
	colorGray     = pdfColor{0.5, 0.5, 0.5}
	colorCodeBg   = pdfColor{0.95, 0.95, 0.95}
	colorH1Color  = pdfColor{0.1, 0.1, 0.4}
	colorH2Color  = pdfColor{0.15, 0.15, 0.5}
	colorH3Color  = pdfColor{0.2, 0.2, 0.55}
	colorLinkColor = pdfColor{0.1, 0.1, 0.8}
	colorAccent   = pdfColor{0.3, 0.3, 0.7}
)

// pdfFontStyle — стиль шрифта
type pdfFontStyle int

const (
	styleRegular pdfFontStyle = iota
	styleBold
	styleItalic
	styleBoldItalic
	styleMono
	styleMonoBold
)

// pdfFont — логический шрифт
type pdfFont struct {
	style pdfFontStyle
	size  float64
}

var (
	fontBody     = pdfFont{styleRegular, fontSizeBody}
	fontBold     = pdfFont{styleBold, fontSizeBody}
	fontItalic   = pdfFont{styleItalic, fontSizeBody}
	fontBoldItal = pdfFont{styleBoldItalic, fontSizeBody}
	fontMono     = pdfFont{styleMono, fontSizeCode}
	fontH1       = pdfFont{styleBold, fontSizeH1}
	fontH2       = pdfFont{styleBold, fontSizeH2}
	fontH3       = pdfFont{styleBold, fontSizeH3}
	fontH4       = pdfFont{styleBold, fontSizeH4}
)

// pdfSpan — фрагмент текста
type pdfSpan struct {
	text    string
	font    pdfFont
	color   pdfColor
	isLink  bool
	linkURL string
}

// pdfBlock — блок контента
type pdfBlock struct {
	kind    string
	spans   []pdfSpan
	rawText string
	indent  int
	bullet  string
}

// === Движок рендеринга ===

// pdfEngine — абстракция над двумя режимами вывода текста
type pdfEngine interface {
	// textCmd возвращает PDF команду для вывода текста
	textCmd(text string, font pdfFont, color pdfColor, x, y float64) string
	// textWidth возвращает ширину строки в pt
	textWidth(text string, font pdfFont) float64
	// fontResources возвращает словарь /Font для страницы
	fontResources() string
	// writeObjects записывает объекты шрифтов в документ
	writeObjects(doc *pdfDoc)
}

// === Fallback engine (встроенные PDF шрифты) ===

type fallbackEngine struct{}

func (e *fallbackEngine) textCmd(text string, font pdfFont, color pdfColor, x, y float64) string {
	return fmt.Sprintf(
		"BT /%s %.2f Tf %.3f %.3f %.3f rg %.2f %.2f Td (%s) Tj ET\n",
		e.fontRef(font), font.size,
		color.r, color.g, color.b,
		x, y,
		pdfEscapeLatin(text),
	)
}

func (e *fallbackEngine) textWidth(text string, font pdfFont) float64 {
	ratio := 0.55
	if font.style == styleMono || font.style == styleMonoBold {
		ratio = 0.6
	}
	return float64(len([]rune(text))) * font.size * ratio
}

func (e *fallbackEngine) fontResources() string {
	return "/Font << /F1 3 0 R /F2 4 0 R /F3 5 0 R /F4 6 0 R /F5 7 0 R /F6 8 0 R >>"
}

func (e *fallbackEngine) writeObjects(doc *pdfDoc) {
	builtins := []string{
		"Helvetica", "Helvetica-Bold", "Helvetica-Oblique",
		"Helvetica-BoldOblique", "Courier", "Courier-Bold",
	}
	for _, name := range builtins {
		doc.newObject()
		doc.write(fmt.Sprintf(
			"<< /Type /Font /Subtype /Type1 /BaseFont /%s /Encoding /WinAnsiEncoding >>\nendobj\n\n",
			name,
		))
	}
}

func (e *fallbackEngine) fontRef(font pdfFont) string {
	switch font.style {
	case styleBold:
		return "F2"
	case styleItalic:
		return "F3"
	case styleBoldItalic:
		return "F4"
	case styleMono:
		return "F5"
	case styleMonoBold:
		return "F6"
	default:
		return "F1"
	}
}

// === TTF engine (системный шрифт с кириллицей) ===

type ttfEngine struct {
	regular  *EmbeddedFont
	bold     *EmbeddedFont
	italic   *EmbeddedFont
	mono     *EmbeddedFont // Courier — встроенный, без кириллицы
	fontPath string

	// ID объектов после записи
	regularRef string
	boldRef    string
	italicRef  string
}

func newTTFEngine(fontPath string) (*ttfEngine, error) {
	ttf, err := LoadTTF(fontPath)
	if err != nil {
		return nil, err
	}
	if !ttf.HasCyrillic() {
		return nil, fmt.Errorf("font has no cyrillic glyphs")
	}

	return &ttfEngine{
		regular:  NewEmbeddedFont(ttf),
		bold:     NewEmbeddedFont(ttf), // используем тот же шрифт для bold (упрощение)
		italic:   NewEmbeddedFont(ttf),
		fontPath: fontPath,
	}, nil
}

func (e *ttfEngine) embeddedFor(font pdfFont) *EmbeddedFont {
	switch font.style {
	case styleBold, styleBoldItalic:
		return e.bold
	case styleItalic:
		return e.italic
	default:
		return e.regular
	}
}

func (e *ttfEngine) textCmd(text string, font pdfFont, color pdfColor, x, y float64) string {
	ef := e.embeddedFor(font)
	// Кодируем в UTF-16BE и регистрируем глифы
	encoded := encodeUTF16BEHex(text, ef)

	fontRef := e.fontRefFor(font)
	return fmt.Sprintf(
		"BT /%s %.2f Tf %.3f %.3f %.3f rg %.2f %.2f Td <%s> Tj ET\n",
		fontRef, font.size,
		color.r, color.g, color.b,
		x, y,
		encoded,
	)
}

func (e *ttfEngine) fontRefFor(font pdfFont) string {
	switch font.style {
	case styleBold, styleBoldItalic:
		return "FB"
	case styleItalic:
		return "FI"
	case styleMono, styleMonoBold:
		return "FM"
	default:
		return "FR"
	}
}

func (e *ttfEngine) textWidth(text string, font pdfFont) float64 {
	if font.style == styleMono || font.style == styleMonoBold {
		return float64(len([]rune(text))) * font.size * 0.6
	}
	ef := e.embeddedFor(font)
	total := 0.0
	for _, r := range text {
		w := ef.GlyphWidth(r)
		total += float64(w) * font.size / 1000.0
	}
	return total
}

func (e *ttfEngine) fontResources() string {
	return fmt.Sprintf(
		"/Font << /FR %s /FB %s /FI %s /FM 3 0 R >>",
		e.regularRef, e.boldRef, e.italicRef,
	)
}

func (e *ttfEngine) writeObjects(doc *pdfDoc) {
	// Courier для кода (встроенный)
	doc.newObject()
	doc.write("<< /Type /Font /Subtype /Type1 /BaseFont /Courier /Encoding /WinAnsiEncoding >>\nendobj\n\n")

	// Если bold и italic указывают на тот же TTF — можно встроить один раз.
	// Для упрощения встраиваем все три отдельно (subset будет разный по использованным глифам).
	e.regularRef = e.regular.WriteToPDF(doc, "GrimoirRegular")
	e.boldRef = e.bold.WriteToPDF(doc, "GrimoirBold")
	e.italicRef = e.italic.WriteToPDF(doc, "GrimoirItalic")
}

// encodeUTF16BEHex кодирует строку в UTF-16BE hex для PDF и регистрирует глифы
func encodeUTF16BEHex(text string, ef *EmbeddedFont) string {
	var sb strings.Builder
	for _, r := range text {
		gid := ef.UseRune(r)
		sb.WriteString(fmt.Sprintf("%04X", gid))
	}
	return sb.String()
}

// === Основной документ ===

type pdfDoc struct {
	buf     bytes.Buffer
	objects []int
	pageIDs []int
	engine  pdfEngine

	curPage int
	curY    float64
	pageBuf bytes.Buffer
}

// ExportToPDF экспортирует markdown в PDF
func ExportToPDF(lines []string, outputPath string) error {
	// Пробуем найти системный шрифт
	var engine pdfEngine
	fontPath := FindCyrillicFont()
	if fontPath != "" {
		ttfe, err := newTTFEngine(fontPath)
		if err == nil {
			engine = ttfe
		}
	}
	if engine == nil {
		engine = &fallbackEngine{}
	}

	blocks := parseMarkdownToBlocks(lines)

	doc := &pdfDoc{engine: engine}
	doc.writePDFHeader()
	doc.addPage()

	for _, block := range blocks {
		doc.renderBlock(block)
	}

	doc.finalizePage()
	doc.writeCrossRef()

	return os.WriteFile(outputPath, doc.buf.Bytes(), 0644)
}

// === Парсинг Markdown → блоки ===

func parseMarkdownToBlocks(lines []string) []pdfBlock {
	var blocks []pdfBlock
	inCode := false
	codeLang := ""
	var codeLines []string

	for _, line := range lines {
		if strings.HasPrefix(line, "```") {
			if inCode {
				blocks = append(blocks, pdfBlock{kind: "code", rawText: strings.Join(codeLines, "\n")})
				inCode = false
				codeLines = nil
				codeLang = ""
			} else {
				inCode = true
				codeLang = strings.TrimSpace(strings.TrimPrefix(line, "```"))
				_ = codeLang
			}
			continue
		}
		if inCode {
			codeLines = append(codeLines, line)
			continue
		}

		if regexp.MustCompile(`^(-{3,}|_{3,}|\*{3,})\s*$`).MatchString(line) {
			blocks = append(blocks, pdfBlock{kind: "hr"})
			continue
		}
		if m := regexp.MustCompile(`^(#{1,4})\s+(.+)`).FindStringSubmatch(line); m != nil {
			level := len(m[1])
			blocks = append(blocks, pdfBlock{
				kind:  fmt.Sprintf("h%d", level),
				spans: parseInlineMarkdown(m[2], fontForHeading(level), colorForHeading(level)),
			})
			continue
		}
		if strings.HasPrefix(line, "> ") {
			blocks = append(blocks, pdfBlock{
				kind:  "quote",
				spans: parseInlineMarkdown(strings.TrimPrefix(line, "> "), fontItalic, colorDarkGray),
			})
			continue
		}
		if m := regexp.MustCompile(`^(\s*)([-*+])\s+(.+)`).FindStringSubmatch(line); m != nil {
			blocks = append(blocks, pdfBlock{
				kind:   "listitem",
				bullet: "•",
				indent: len(m[1]) / 2,
				spans:  parseInlineMarkdown(m[3], fontBody, colorBlack),
			})
			continue
		}
		if m := regexp.MustCompile(`^(\s*)(\d+)\.\s+(.+)`).FindStringSubmatch(line); m != nil {
			blocks = append(blocks, pdfBlock{
				kind:   "listitem",
				bullet: m[2] + ".",
				indent: len(m[1]) / 2,
				spans:  parseInlineMarkdown(m[3], fontBody, colorBlack),
			})
			continue
		}
		if strings.TrimSpace(line) == "" {
			blocks = append(blocks, pdfBlock{kind: "space"})
			continue
		}
		if strings.Contains(line, "|") && strings.HasPrefix(strings.TrimSpace(line), "|") {
			if regexp.MustCompile(`^\|[\s\-:|]+\|`).MatchString(strings.TrimSpace(line)) {
				blocks = append(blocks, pdfBlock{kind: "hr"})
				continue
			}
			cells := strings.Split(strings.Trim(strings.TrimSpace(line), "|"), "|")
			var spans []pdfSpan
			for i, c := range cells {
				if i > 0 {
					spans = append(spans, pdfSpan{text: "  |  ", font: fontBody, color: colorGray})
				}
				spans = append(spans, parseInlineMarkdown(strings.TrimSpace(c), fontBody, colorBlack)...)
			}
			blocks = append(blocks, pdfBlock{kind: "para", spans: spans})
			continue
		}
		blocks = append(blocks, pdfBlock{
			kind:  "para",
			spans: parseInlineMarkdown(line, fontBody, colorBlack),
		})
	}
	return blocks
}

func parseInlineMarkdown(text string, defaultFont pdfFont, defaultColor pdfColor) []pdfSpan {
	type fragment struct {
		text   string
		bold, italic, isCode, isLink bool
		linkURL string
		start, end int
	}

	patterns := []struct {
		re   *regexp.Regexp
		kind string
	}{
		{regexp.MustCompile(`\*\*([^*]+)\*\*`), "bold"},
		{regexp.MustCompile(`\*([^*]+)\*`), "italic"},
		{regexp.MustCompile("`([^`]+)`"), "code"},
		{regexp.MustCompile(`\[([^\]]+)\]\(([^)]+)\)`), "link"},
	}

	frags := []fragment{}
	used := make([]bool, len(text))

	for _, p := range patterns {
		for _, m := range p.re.FindAllStringSubmatchIndex(text, -1) {
			overlap := false
			for i := m[0]; i < m[1] && i < len(used); i++ {
				if used[i] {
					overlap = true
					break
				}
			}
			if overlap {
				continue
			}
			for i := m[0]; i < m[1] && i < len(used); i++ {
				used[i] = true
			}
			f := fragment{start: m[0], end: m[1]}
			switch p.kind {
			case "bold":
				f.text = text[m[2]:m[3]]
				f.bold = true
			case "italic":
				f.text = text[m[2]:m[3]]
				f.italic = true
			case "code":
				f.text = text[m[2]:m[3]]
				f.isCode = true
			case "link":
				f.text = text[m[2]:m[3]]
				f.isLink = true
				if len(m) > 5 && m[4] >= 0 {
					f.linkURL = text[m[4]:m[5]]
				}
			}
			frags = append(frags, f)
		}
	}
	// Сортировка по позиции
	for i := range frags {
		for j := i + 1; j < len(frags); j++ {
			if frags[j].start < frags[i].start {
				frags[i], frags[j] = frags[j], frags[i]
			}
		}
	}

	var spans []pdfSpan
	pos := 0
	for _, f := range frags {
		if f.start > pos {
			spans = append(spans, pdfSpan{text: text[pos:f.start], font: defaultFont, color: defaultColor})
		}
		var font pdfFont
		var color pdfColor
		switch {
		case f.isCode:
			font = fontMono
			color = pdfColor{0.1, 0.1, 0.5}
		case f.isLink:
			font = defaultFont
			color = colorLinkColor
		case f.bold && f.italic:
			font = fontBoldItal
			color = defaultColor
		case f.bold:
			font = fontBold
			color = defaultColor
		case f.italic:
			font = fontItalic
			color = defaultColor
		default:
			font = defaultFont
			color = defaultColor
		}
		spans = append(spans, pdfSpan{text: f.text, font: font, color: color, isLink: f.isLink, linkURL: f.linkURL})
		pos = f.end
	}
	if pos < len(text) && pos >= 0 {
		spans = append(spans, pdfSpan{text: text[pos:], font: defaultFont, color: defaultColor})
	}
	if len(spans) == 0 {
		spans = []pdfSpan{{text: text, font: defaultFont, color: defaultColor}}
	}
	return spans
}

func fontForHeading(level int) pdfFont {
	switch level {
	case 1:
		return fontH1
	case 2:
		return fontH2
	case 3:
		return fontH3
	default:
		return fontH4
	}
}

func colorForHeading(level int) pdfColor {
	switch level {
	case 1:
		return colorH1Color
	case 2:
		return colorH2Color
	case 3:
		return colorH3Color
	default:
		return colorDarkGray
	}
}

// === Генерация PDF ===

func (doc *pdfDoc) writePDFHeader() {
	doc.write("%PDF-1.4\n")
	doc.write("%\xe2\xe3\xcf\xd3\n")
}

func (doc *pdfDoc) addPage() {
	doc.curPage++
	doc.curY = marginT
	doc.pageBuf.Reset()
}

func (doc *pdfDoc) finalizePage() {
	if doc.pageBuf.Len() == 0 && doc.curPage == 0 {
		return
	}

	stream := doc.pageBuf.String()
	contentID := doc.newObject()
	doc.write(fmt.Sprintf("<< /Length %d >>\nstream\n", len(stream)))
	doc.write(stream)
	doc.write("\nendstream\nendobj\n\n")

	pageID := doc.newObject()
	doc.write(fmt.Sprintf(
		"<< /Type /Page /Parent 2 0 R /MediaBox [0 0 %.2f %.2f]\n"+
			"   /Contents %d 0 R\n"+
			"   /Resources << %s >>\n"+
			">>\nendobj\n\n",
		pageWidth, pageHeight, contentID,
		doc.engine.fontResources(),
	))
	doc.pageIDs = append(doc.pageIDs, pageID)
}

func (doc *pdfDoc) renderBlock(block pdfBlock) {
	switch block.kind {
	case "space":
		doc.advanceY(fontSizeBody * 0.5)

	case "hr":
		doc.advanceY(8)
		doc.checkPageBreak(20)
		y := pageHeight - doc.curY
		doc.pageBuf.WriteString(fmt.Sprintf(
			"q %.3f %.3f %.3f RG 0.5 w %.2f %.2f m %.2f %.2f l S Q\n",
			colorGray.r, colorGray.g, colorGray.b,
			marginL, y, pageWidth-marginR, y,
		))
		doc.advanceY(8)

	case "h1":
		doc.advanceY(fontSizeH1 * 0.6)
		doc.checkPageBreak(fontSizeH1 * 2.5)
		doc.renderHeading(block, fontH1, colorH1Color)
		y := pageHeight - doc.curY + 2
		doc.pageBuf.WriteString(fmt.Sprintf(
			"q %.3f %.3f %.3f RG 1 w %.2f %.2f m %.2f %.2f l S Q\n",
			colorAccent.r, colorAccent.g, colorAccent.b,
			marginL, y, pageWidth-marginR, y,
		))
		doc.advanceY(6)

	case "h2":
		doc.advanceY(fontSizeH2 * 0.5)
		doc.checkPageBreak(fontSizeH2 * 2.5)
		doc.renderHeading(block, fontH2, colorH2Color)
		doc.advanceY(4)

	case "h3":
		doc.advanceY(fontSizeH3 * 0.4)
		doc.checkPageBreak(fontSizeH3 * 2)
		doc.renderHeading(block, fontH3, colorH3Color)
		doc.advanceY(3)

	case "h4":
		doc.advanceY(fontSizeH4 * 0.3)
		doc.checkPageBreak(fontSizeH4 * 2)
		doc.renderHeading(block, fontH4, colorDarkGray)
		doc.advanceY(2)

	case "para":
		doc.checkPageBreak(fontSizeBody * lineHeightMul * 2)
		doc.renderSpans(block.spans, marginL, fontSizeBody*lineHeightMul)
		doc.advanceY(fontSizeBody * 0.3)

	case "quote":
		doc.advanceY(4)
		doc.checkPageBreak(fontSizeBody * lineHeightMul * 2)
		startY := doc.curY
		doc.renderSpans(block.spans, marginL+16, fontSizeBody*lineHeightMul)
		endY := doc.curY
		barH := endY - startY + fontSizeBody
		barY := pageHeight - startY
		doc.pageBuf.WriteString(fmt.Sprintf(
			"q %.3f %.3f %.3f rg %.2f %.2f %.2f %.2f re f Q\n",
			colorAccent.r, colorAccent.g, colorAccent.b,
			marginL, barY-barH, 3.0, barH,
		))
		doc.pageBuf.WriteString(fmt.Sprintf(
			"q 0.96 0.96 0.98 rg %.2f %.2f %.2f %.2f re f Q\n",
			marginL+4, barY-barH, textWidth-4, barH,
		))
		doc.advanceY(4)

	case "listitem":
		doc.checkPageBreak(fontSizeBody * lineHeightMul * 1.5)
		bulletX := marginL + float64(block.indent)*20
		textX := bulletX + 18
		bulletY := pageHeight - doc.curY - fontSizeBody
		doc.pageBuf.WriteString(doc.engine.textCmd(
			block.bullet, fontBody, colorAccent, bulletX, bulletY,
		))
		doc.renderSpans(block.spans, textX, fontSizeBody*lineHeightMul)
		doc.advanceY(2)

	case "code":
		doc.renderCodeBlock(block.rawText)
	}
}

func (doc *pdfDoc) renderHeading(block pdfBlock, font pdfFont, color pdfColor) {
	var sb strings.Builder
	for _, s := range block.spans {
		sb.WriteString(s.text)
	}
	y := pageHeight - doc.curY - font.size
	doc.pageBuf.WriteString(doc.engine.textCmd(sb.String(), font, color, marginL, y))
	doc.advanceY(font.size * lineHeightMul)
}

func (doc *pdfDoc) renderSpans(spans []pdfSpan, leftMargin, lineHeight float64) {
	maxW := pageWidth - marginR - (leftMargin - marginL)
	wrappedLines := wrapSpans(spans, maxW, doc.engine)

	for _, line := range wrappedLines {
		doc.checkPageBreak(lineHeight)
		y := pageHeight - doc.curY - fontSizeBody
		x := leftMargin
		for _, span := range line {
			if span.text == "" {
				continue
			}
			doc.pageBuf.WriteString(doc.engine.textCmd(span.text, span.font, span.color, x, y))
			x += doc.engine.textWidth(span.text, span.font)
		}
		doc.advanceY(lineHeight)
	}
}

func (doc *pdfDoc) renderCodeBlock(code string) {
	lines := strings.Split(code, "\n")
	lineH := fontSizeCode * lineHeightMul
	totalH := float64(len(lines))*lineH + 16

	doc.advanceY(6)
	doc.checkPageBreak(math.Min(totalH, pageHeight-marginT-marginB))

	bgY := pageHeight - doc.curY
	bgH := float64(len(lines))*lineH + 12
	doc.pageBuf.WriteString(fmt.Sprintf(
		"q %.3f %.3f %.3f rg %.2f %.2f %.2f %.2f re f Q\n",
		colorCodeBg.r, colorCodeBg.g, colorCodeBg.b,
		marginL, bgY-bgH, textWidth, bgH,
	))
	doc.pageBuf.WriteString(fmt.Sprintf(
		"q %.3f %.3f %.3f rg %.2f %.2f %.2f %.2f re f Q\n",
		colorAccent.r, colorAccent.g, colorAccent.b,
		marginL, bgY-bgH, 3.0, bgH,
	))

	doc.advanceY(8)
	for _, line := range lines {
		doc.checkPageBreak(lineH)
		y := pageHeight - doc.curY - fontSizeCode
		doc.pageBuf.WriteString(doc.engine.textCmd(line, fontMono, colorDarkGray, marginL+8, y))
		doc.advanceY(lineH)
	}
	doc.advanceY(6)
}

// wrapSpans разбивает spans на строки по maxWidth
func wrapSpans(spans []pdfSpan, maxWidth float64, eng pdfEngine) [][]pdfSpan {
	var result [][]pdfSpan
	var curLine []pdfSpan
	curW := 0.0

	for _, span := range spans {
		words := strings.Fields(span.text)
		if len(words) == 0 {
			curLine = append(curLine, span)
			continue
		}
		for i, word := range words {
			ww := eng.textWidth(word, span.font)
			sw := eng.textWidth(" ", span.font)
			needSpace := i > 0 || (len(curLine) > 0 && curW > 0)
			addW := ww
			if needSpace {
				addW += sw
			}
			if curW+addW > maxWidth && curW > 0 {
				result = append(result, curLine)
				curLine = nil
				curW = 0
				needSpace = false
				addW = ww
			}
			txt := word
			if needSpace {
				txt = " " + word
			}
			curLine = append(curLine, pdfSpan{text: txt, font: span.font, color: span.color})
			curW += addW
		}
	}
	if len(curLine) > 0 {
		result = append(result, curLine)
	}
	if len(result) == 0 {
		result = [][]pdfSpan{{}}
	}
	return result
}

// === Финализация документа ===

func (doc *pdfDoc) writeCrossRef() {
	// Catalog
	doc.newObject()
	doc.write("<< /Type /Catalog /Pages 2 0 R >>\nendobj\n\n")

	// Pages
	var pageRefs strings.Builder
	for _, id := range doc.pageIDs {
		pageRefs.WriteString(fmt.Sprintf("%d 0 R ", id))
	}
	doc.newObject()
	doc.write(fmt.Sprintf(
		"<< /Type /Pages /Kids [%s] /Count %d >>\nendobj\n\n",
		pageRefs.String(), len(doc.pageIDs),
	))

	// Объекты шрифтов
	doc.engine.writeObjects(doc)

	// Info
	now := time.Now().Format("20060102150405")
	doc.newObject()
	doc.write(fmt.Sprintf(
		"<< /Creator (grimoir) /CreationDate (D:%s) >>\nendobj\n\n",
		now,
	))

	// xref
	xrefOff := doc.buf.Len()
	total := len(doc.objects) + 1
	doc.write(fmt.Sprintf("xref\n0 %d\n", total))
	doc.write("0000000000 65535 f \n")
	for _, off := range doc.objects {
		doc.write(fmt.Sprintf("%010d 00000 n \n", off))
	}
	doc.write(fmt.Sprintf(
		"trailer\n<< /Size %d /Root 1 0 R >>\nstartxref\n%d\n%%%%EOF\n",
		total, xrefOff,
	))
}

// === Утилиты ===

func (doc *pdfDoc) write(s string) { doc.buf.WriteString(s) }

func (doc *pdfDoc) newObject() int {
	id := len(doc.objects) + 1
	doc.objects = append(doc.objects, doc.buf.Len())
	doc.write(fmt.Sprintf("%d 0 obj\n", id))
	return id
}

func (doc *pdfDoc) advanceY(d float64) { doc.curY += d }

func (doc *pdfDoc) checkPageBreak(needed float64) {
	if doc.curY+needed > pageHeight-marginB {
		doc.finalizePage()
		doc.addPage()
	}
}

// pdfEscapeLatin экранирует строку для Latin-1 PDF (fallback режим)
func pdfEscapeLatin(s string) string {
	var b strings.Builder
	for _, r := range s {
		switch {
		case r == '(':
			b.WriteString(`\(`)
		case r == ')':
			b.WriteString(`\)`)
		case r == '\\':
			b.WriteString(`\\`)
		case r >= 0x20 && r <= 0x7E:
			b.WriteRune(r)
		default:
			b.WriteString(translitRune(r))
		}
	}
	return b.String()
}

// translitRune транслитерирует символ (fallback)
func translitRune(r rune) string {
	m := map[rune]string{
		'а': "a", 'б': "b", 'в': "v", 'г': "g", 'д': "d",
		'е': "e", 'ё': "yo", 'ж': "zh", 'з': "z", 'и': "i",
		'й': "j", 'к': "k", 'л': "l", 'м': "m", 'н': "n",
		'о': "o", 'п': "p", 'р': "r", 'с': "s", 'т': "t",
		'у': "u", 'ф': "f", 'х': "kh", 'ц': "ts", 'ч': "ch",
		'ш': "sh", 'щ': "shch", 'ъ': "", 'ы': "y", 'ь': "",
		'э': "e", 'ю': "yu", 'я': "ya",
		'А': "A", 'Б': "B", 'В': "V", 'Г': "G", 'Д': "D",
		'Е': "E", 'Ё': "Yo", 'Ж': "Zh", 'З': "Z", 'И': "I",
		'Й': "J", 'К': "K", 'Л': "L", 'М': "M", 'Н': "N",
		'О': "O", 'П': "P", 'Р': "R", 'С': "S", 'Т': "T",
		'У': "U", 'Ф': "F", 'Х': "Kh", 'Ц': "Ts", 'Ч': "Ch",
		'Ш': "Sh", 'Щ': "Shch", 'Ъ': "", 'Ы': "Y", 'Ь': "",
		'Э': "E", 'Ю': "Yu", 'Я': "Ya",
		'—': "--", '–': "-", '«': "\"", '»': "\"",
		'\u00a0': " ", '…': "...", '•': "*",
		'©': "(c)", '®': "(r)", '™': "(tm)",
	}
	if s, ok := m[r]; ok {
		return s
	}
	if r <= 0xFF {
		return string(r)
	}
	return "?"
}

// defaultPDFPath путь для PDF рядом с md файлом
func defaultPDFPath(mdPath string) string {
	ext := filepath.Ext(mdPath)
	return strings.TrimSuffix(mdPath, ext) + ".pdf"
}

// sanitizePDF — заглушка, реальная обработка в движке
func sanitizePDF(s string) string { return s }