初始化仓库

core/markdown_slack.go

@@ -0,0 +1,131 @@
+package core
+
+import (
+	"regexp"
+	"strings"
+)
+
+// Slack mrkdwn regex patterns (compiled once).
+var (
+	reSlackCodeBlock  = regexp.MustCompile("(?s)```[a-zA-Z]*\n?(.*?)```")
+	reSlackInlineCode = regexp.MustCompile("`([^`]+)`")
+	reSlackLink       = regexp.MustCompile(`\[([^\]]+)\]\(([^)]+)\)`)
+	reSlackBoldItalic = regexp.MustCompile(`\*\*\*(.+?)\*\*\*`)
+	reSlackBold       = regexp.MustCompile(`\*\*(.+?)\*\*`)
+	reSlackStrike     = regexp.MustCompile(`~~(.+?)~~`)
+	reSlackHeading    = regexp.MustCompile(`^#{1,6}\s+(.+)$`)
+	reSlackImgTag     = regexp.MustCompile(`!\[([^\]]*)\]\(([^)]+)\)`)
+)
+
+// MarkdownToSlackMrkdwn converts standard Markdown to Slack mrkdwn format.
+//
+// Key conversions:
+//   - **bold** → *bold*
+//   - *italic* → _italic_ (single asterisk → underscore)
+//   - ~~strike~~ → ~strike~
+//   - [text](url) → <url|text>
+//   - # Heading → *Heading*
+//   - Code blocks and inline code are preserved as-is.
+func MarkdownToSlackMrkdwn(md string) string {
+	// Split into code blocks vs non-code segments so we don't
+	// accidentally convert syntax inside code.
+	type segment struct {
+		text   string
+		isCode bool
+	}
+
+	var segments []segment
+	rest := md
+	for {
+		loc := reSlackCodeBlock.FindStringIndex(rest)
+		if loc == nil {
+			segments = append(segments, segment{text: rest})
+			break
+		}
+		if loc[0] > 0 {
+			segments = append(segments, segment{text: rest[:loc[0]]})
+		}
+		segments = append(segments, segment{text: rest[loc[0]:loc[1]], isCode: true})
+		rest = rest[loc[1]:]
+	}
+
+	var b strings.Builder
+	b.Grow(len(md) + len(md)/8)
+
+	for _, seg := range segments {
+		if seg.isCode {
+			b.WriteString(seg.text)
+			continue
+		}
+		b.WriteString(convertSlackInline(seg.text))
+	}
+
+	return b.String()
+}
+
+// convertSlackInline converts inline Markdown formatting to Slack mrkdwn.
+// Must NOT be called on code block content.
+func convertSlackInline(s string) string {
+	// Protect inline code from further processing.
+	type placeholder struct {
+		key     string
+		content string
+	}
+	var phs []placeholder
+	phIdx := 0
+
+	nextPH := func(content string) string {
+		key := "\x00SL" + string(rune('0'+phIdx)) + "\x00"
+		phs = append(phs, placeholder{key: key, content: content})
+		phIdx++
+		return key
+	}
+
+	// 1. Protect inline code spans.
+	s = reSlackInlineCode.ReplaceAllStringFunc(s, func(m string) string {
+		return nextPH(m) // keep as-is
+	})
+
+	// 2. Image tags → just the alt text or URL (Slack can't render inline images).
+	s = reSlackImgTag.ReplaceAllStringFunc(s, func(m string) string {
+		sm := reSlackImgTag.FindStringSubmatch(m)
+		if sm[1] != "" {
+			return sm[1]
+		}
+		return sm[2]
+	})
+
+	// 3. Links: [text](url) → <url|text>
+	s = reSlackLink.ReplaceAllStringFunc(s, func(m string) string {
+		sm := reSlackLink.FindStringSubmatch(m)
+		if len(sm) < 3 {
+			return m
+		}
+		return nextPH("<" + sm[2] + "|" + sm[1] + ">")
+	})
+
+	// 4. Bold-italic: ***text*** → *_text_* (must precede bold)
+	s = reSlackBoldItalic.ReplaceAllString(s, "*_${1}_*")
+
+	// 5. Bold: **text** → *text*
+	s = reSlackBold.ReplaceAllString(s, "*${1}*")
+
+	// 6. Strikethrough: ~~text~~ → ~text~
+	s = reSlackStrike.ReplaceAllString(s, "~${1}~")
+
+	// 7. Headings: # Heading → *Heading* (line-by-line)
+	lines := strings.Split(s, "\n")
+	for i, line := range lines {
+		if m := reSlackHeading.FindStringSubmatch(line); m != nil {
+			lines[i] = "*" + m[1] + "*"
+		}
+	}
+	s = strings.Join(lines, "\n")
+
+	// Restore placeholders.
+	for _, ph := range phs {
+		s = strings.Replace(s, ph.key, ph.content, 1)
+	}
+
+	return s
+}