(new): v1.2 release

tgfmt/mdv2.go

@@ -41,7 +41,7 @@ func (s MarkdownV2) Mention(userID uint64) MarkdownV2 {
 
 // Emoji returns s as a Telegram MarkdownV2 custom emoji.
 func (s MarkdownV2) Emoji(emojiID string) MarkdownV2 {
-	return "[" + s + "](tg://emoji?id=" + escapeMarkdownV2LinkDestination(emojiID) + ")"
+	return "![" + s + "](tg://emoji?id=" + escapeMarkdownV2LinkDestination(emojiID) + ")"
 }
 
 // Time returns s as a Telegram MarkdownV2 localized timestamp.
@@ -56,14 +56,19 @@ func (s MarkdownV2) TimeFormat(unix uint64, format string) MarkdownV2 {
 }
 
 // InlineCode returns s wrapped as inline code Telegram MarkdownV2 text.
-func (s MarkdownV2) InlineCode() MarkdownV2 { return "`" + s + "`" }
+func (s MarkdownV2) InlineCode() MarkdownV2 {
+	return "`" + escapeMarkdownV2Code(unescapeMarkdownV2Fragment(s)) + "`"
+}
 
 // BlockCode returns s wrapped as a Telegram MarkdownV2 code block.
-func (s MarkdownV2) BlockCode() MarkdownV2 { return "```\n" + s + "\n```" }
+func (s MarkdownV2) BlockCode() MarkdownV2 {
+	return "```\n" + escapeMarkdownV2Code(unescapeMarkdownV2Fragment(s)) + "\n```"
+}
 
 // BlockCodeLanguage returns s wrapped as a Telegram MarkdownV2 code block with language.
 func (s MarkdownV2) BlockCodeLanguage(lang string) MarkdownV2 {
-	return "```" + MarkdownV2(lang) + "\n" + s + "\n```"
+	return "```" + MarkdownV2(sanitizeMarkdownV2CodeLanguage(lang)) + "\n" +
+		escapeMarkdownV2Code(unescapeMarkdownV2Fragment(s)) + "\n```"
 }
 
 // Quote returns s as a Telegram MarkdownV2 blockquote.
@@ -72,7 +77,39 @@ func (s MarkdownV2) Quote() MarkdownV2 {
 }
 
 // QuoteExpandable returns s as a Telegram MarkdownV2 expandable blockquote.
-func (s MarkdownV2) QuoteExpandable() MarkdownV2 { return "**>" + s }
+func (s MarkdownV2) QuoteExpandable() MarkdownV2 {
+	return MarkdownV2("**>" + strings.ReplaceAll(string(s), "\n", "\n>") + "||")
+}
+
+func unescapeMarkdownV2Fragment(s MarkdownV2) string {
+	fragment := string(s)
+	var result strings.Builder
+	result.Grow(len(fragment))
+	for i := 0; i < len(fragment); i++ {
+		if fragment[i] == '\\' && i+1 < len(fragment) && fragment[i+1] >= 1 && fragment[i+1] <= 126 {
+			i++
+		}
+		result.WriteByte(fragment[i])
+	}
+	return result.String()
+}
+
+func escapeMarkdownV2Code(s string) MarkdownV2 {
+	s = strings.ReplaceAll(s, "\\", "\\\\")
+	s = strings.ReplaceAll(s, "`", "\\`")
+	return MarkdownV2(s)
+}
+
+func sanitizeMarkdownV2CodeLanguage(lang string) string {
+	return strings.Map(func(r rune) rune {
+		switch r {
+		case '`', '\\', '\r', '\n':
+			return -1
+		default:
+			return r
+		}
+	}, lang)
+}
 
 func escapeMarkdownV2LinkDestination(s string) MarkdownV2 {
 	s = strings.ReplaceAll(s, "\\", "\\\\")