init commit

2026-02-05 15:33:07 -06:00
commit e70b629b4a
13 changed files with 1021 additions and 0 deletions
--- a/convert/rtf.go
+++ b/convert/rtf.go
@@ -0,0 +1,430 @@
+package convert
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/extension"
+	extast "github.com/yuin/goldmark/extension/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+// RTFRenderer converts a Goldmark AST to RTF.
+type RTFRenderer struct {
+	orderedIndex int // tracks current ordered list item number
+}
+
+func NewRTFRenderer() *RTFRenderer {
+	return &RTFRenderer{}
+}
+
+func (r *RTFRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	// Block nodes
+	reg.Register(ast.KindDocument, r.renderDocument)
+	reg.Register(ast.KindHeading, r.renderHeading)
+	reg.Register(ast.KindParagraph, r.renderParagraph)
+	reg.Register(ast.KindCodeBlock, r.renderCodeBlock)
+	reg.Register(ast.KindFencedCodeBlock, r.renderFencedCodeBlock)
+	reg.Register(ast.KindBlockquote, r.renderBlockquote)
+	reg.Register(ast.KindList, r.renderList)
+	reg.Register(ast.KindListItem, r.renderListItem)
+	reg.Register(ast.KindThematicBreak, r.renderThematicBreak)
+	reg.Register(ast.KindHTMLBlock, r.renderRaw)
+	reg.Register(ast.KindTextBlock, r.renderTextBlock)
+	// Inline nodes
+	reg.Register(ast.KindText, r.renderText)
+	reg.Register(ast.KindString, r.renderString)
+	reg.Register(ast.KindEmphasis, r.renderEmphasis)
+	reg.Register(ast.KindCodeSpan, r.renderCodeSpan)
+	reg.Register(ast.KindLink, r.renderLink)
+	reg.Register(ast.KindAutoLink, r.renderAutoLink)
+	reg.Register(ast.KindImage, r.renderImage)
+	reg.Register(ast.KindRawHTML, r.renderRaw)
+	// GFM extensions
+	reg.Register(extast.KindStrikethrough, r.renderStrikethrough)
+	reg.Register(extast.KindTable, r.renderTable)
+	reg.Register(extast.KindTableHeader, r.renderTableHeader)
+	reg.Register(extast.KindTableRow, r.renderTableRow)
+	reg.Register(extast.KindTableCell, r.renderTableCell)
+	reg.Register(extast.KindTaskCheckBox, r.renderTaskCheckBox)
+}
+
+// --- Block nodes ---
+
+func (r *RTFRenderer) renderDocument(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\rtf1\ansi\deff0 {\fonttbl{\f0 Helvetica;}{\f1\fmodern Courier;}}`)
+		_, _ = w.WriteString("\n")
+	} else {
+		_, _ = w.WriteString("}")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	h := node.(*ast.Heading)
+	if entering {
+		// Font sizes: H1=36, H2=32, H3=28, H4=24, H5=22, H6=20
+		sizes := [7]int{0, 36, 32, 28, 24, 22, 20}
+		level := h.Level
+		if level < 1 || level > 6 {
+			level = 6
+		}
+		fs := sizes[level] * 2 // RTF font size is in half-points
+		fmt.Fprintf(w, `{\pard\sb240\sa120\b\fs%d `, fs)
+	} else {
+		_, _ = w.WriteString(`\b0\par}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderParagraph(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\pard\sa120 `)
+	} else {
+		_, _ = w.WriteString(`\par}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderCodeBlock(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\pard\f1\fs20 `)
+		r.writeLines(w, source, node)
+		_, _ = w.WriteString(`\par}`)
+		_, _ = w.WriteString("\n")
+		return ast.WalkSkipChildren, nil
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderFencedCodeBlock(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\pard\f1\fs20 `)
+		r.writeLines(w, source, node)
+		_, _ = w.WriteString(`\par}`)
+		_, _ = w.WriteString("\n")
+		return ast.WalkSkipChildren, nil
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderBlockquote(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\pard\li720\ri720\i `)
+	} else {
+		_, _ = w.WriteString(`\i0\par}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderList(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		list := node.(*ast.List)
+		if list.IsOrdered() {
+			r.orderedIndex = int(list.Start)
+		} else {
+			r.orderedIndex = 0
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderListItem(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\pard\li360\fi-360 `)
+		parent := node.Parent()
+		if list, ok := parent.(*ast.List); ok && list.IsOrdered() {
+			fmt.Fprintf(w, `%d.\tab `, r.orderedIndex)
+			r.orderedIndex++
+		} else {
+			_, _ = w.WriteString(`\bullet\tab `)
+		}
+	} else {
+		_, _ = w.WriteString(`\par}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderThematicBreak(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\pard\brdrb\brdrs\brdrw10\brsp20\par}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderTextBlock(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	// TextBlock is used inside blockquotes; just pass through.
+	if !entering {
+		_, _ = w.WriteString(`\line `)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderRaw(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	// Skip raw HTML in RTF output
+	if entering {
+		return ast.WalkSkipChildren, nil
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Inline nodes ---
+
+func (r *RTFRenderer) renderText(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		t := node.(*ast.Text)
+		writeRTFEscaped(w, t.Segment.Value(source))
+		if t.SoftLineBreak() {
+			_, _ = w.WriteString(" ")
+		}
+		if t.HardLineBreak() {
+			_, _ = w.WriteString(`\line `)
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderString(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		s := node.(*ast.String)
+		writeRTFEscaped(w, s.Value)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderEmphasis(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	e := node.(*ast.Emphasis)
+	if e.Level == 2 {
+		// Bold
+		if entering {
+			_, _ = w.WriteString(`{\b `)
+		} else {
+			_, _ = w.WriteString(`}`)
+		}
+	} else {
+		// Italic
+		if entering {
+			_, _ = w.WriteString(`{\i `)
+		} else {
+			_, _ = w.WriteString(`}`)
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderCodeSpan(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\f1 `)
+		for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+			if t, ok := c.(*ast.Text); ok {
+				writeRTFEscaped(w, t.Segment.Value(source))
+			}
+		}
+		_, _ = w.WriteString(`}`)
+		return ast.WalkSkipChildren, nil
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	link := node.(*ast.Link)
+	if entering {
+		_, _ = w.WriteString(`{\field{\*\fldinst HYPERLINK "`)
+		writeRTFEscaped(w, link.Destination)
+		_, _ = w.WriteString(`"}{\fldrslt\ul `)
+	} else {
+		_, _ = w.WriteString(`}}`)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderAutoLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	link := node.(*ast.AutoLink)
+	if entering {
+		url := link.URL(source)
+		_, _ = w.WriteString(`{\field{\*\fldinst HYPERLINK "`)
+		writeRTFEscaped(w, url)
+		_, _ = w.WriteString(`"}{\fldrslt\ul `)
+		writeRTFEscaped(w, url)
+		_, _ = w.WriteString(`}}`)
+		return ast.WalkSkipChildren, nil
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`[image: `)
+		// Alt text is stored in child text nodes
+		for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+			if t, ok := c.(*ast.Text); ok {
+				writeRTFEscaped(w, t.Segment.Value(source))
+			}
+		}
+		_, _ = w.WriteString(`]`)
+		return ast.WalkSkipChildren, nil
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- GFM extension nodes ---
+
+func (r *RTFRenderer) renderStrikethrough(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\strike `)
+	} else {
+		_, _ = w.WriteString(`}`)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderTable(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderTableHeader(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	// TableHeader acts as a row: Table > TableHeader > TableCell
+	if entering {
+		_, _ = w.WriteString(`{\trowd\trgaph108 `)
+		cellCount := 0
+		for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+			cellCount++
+		}
+		for i := 1; i <= cellCount; i++ {
+			fmt.Fprintf(w, `\cellx%d `, i*2880)
+		}
+	} else {
+		_, _ = w.WriteString(`\row}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderTableRow(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_, _ = w.WriteString(`{\trowd\trgaph108 `)
+		// Calculate cell boundaries
+		cellCount := 0
+		for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+			cellCount++
+		}
+		for i := 1; i <= cellCount; i++ {
+			fmt.Fprintf(w, `\cellx%d `, i*2880)
+		}
+	} else {
+		_, _ = w.WriteString(`\row}`)
+		_, _ = w.WriteString("\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderTableCell(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	isHeader := node.Parent().Kind() == extast.KindTableHeader
+	if entering {
+		_, _ = w.WriteString(`{\pard\intbl `)
+		if isHeader {
+			_, _ = w.WriteString(`\b `)
+		}
+	} else {
+		if isHeader {
+			_, _ = w.WriteString(`\b0`)
+		}
+		_, _ = w.WriteString(`\cell}`)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *RTFRenderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		cb := node.(*extast.TaskCheckBox)
+		if cb.IsChecked {
+			_, _ = w.WriteString(`[X] `)
+		} else {
+			_, _ = w.WriteString(`[ ] `)
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Helpers ---
+
+func (r *RTFRenderer) writeLines(w util.BufWriter, source []byte, node ast.Node) {
+	lines := node.Lines()
+	for i := 0; i < lines.Len(); i++ {
+		line := lines.At(i)
+		value := line.Value(source)
+		// Replace newlines with RTF line breaks
+		for _, b := range value {
+			if b == '\n' {
+				_, _ = w.WriteString(`\line `)
+			} else {
+				writeRTFEscapedByte(w, b)
+			}
+		}
+	}
+}
+
+func writeRTFEscaped(w util.BufWriter, data []byte) {
+	for _, b := range data {
+		writeRTFEscapedByte(w, b)
+	}
+}
+
+func writeRTFEscapedByte(w util.BufWriter, b byte) {
+	switch b {
+	case '\\':
+		_, _ = w.WriteString(`\\`)
+	case '{':
+		_, _ = w.WriteString(`\{`)
+	case '}':
+		_, _ = w.WriteString(`\}`)
+	default:
+		_ = w.WriteByte(b)
+	}
+}
+
+// Convert takes markdown bytes and returns RTF bytes.
+func Convert(source []byte) ([]byte, error) {
+	md := goldmark.New(
+		goldmark.WithExtensions(extension.GFM),
+		goldmark.WithRenderer(
+			renderer.NewRenderer(
+				renderer.WithNodeRenderers(
+					util.Prioritized(NewRTFRenderer(), 100),
+				),
+			),
+		),
+	)
+
+	var buf bytes.Buffer
+	if err := md.Convert(source, &buf); err != nil {
+		return nil, fmt.Errorf("conversion failed: %w", err)
+	}
+	return buf.Bytes(), nil
+}
+
+// ConvertToHTML takes markdown bytes and returns HTML bytes.
+// Used for clipboard on platforms where apps expect text/html (web apps like Slack, Gmail).
+func ConvertToHTML(source []byte) ([]byte, error) {
+	md := goldmark.New(
+		goldmark.WithExtensions(extension.GFM),
+	)
+
+	var buf bytes.Buffer
+	if err := md.Convert(source, &buf); err != nil {
+		return nil, fmt.Errorf("html conversion failed: %w", err)
+	}
+	return buf.Bytes(), nil
+}