fix(markdown): preserve user code block characters (#1750)

Co-authored-by: Leonid Skorobogatyy <bash@opencode.itc.local>
2026-06-24 18:33:50 +03:00
parent 8c551c40aa
commit 569342b3c2
3 changed files with 112 additions and 42 deletions
@@ -0,0 +1,55 @@
+import type { AgentMentionInfo } from '../types';
+import { buildAgentHref, buildSkillHref } from '@/lib/messages/inlineMessageLinks';
+
+export const SKILL_TOKEN_PATTERN = /(^|\s)\/([a-z0-9](?:[a-z0-9-]{0,62}[a-z0-9])?)/g;
+
+const FENCED_CODE_SEGMENT_PATTERN = /(```[\s\S]*?```|~~~[\s\S]*?~~~)/g;
+
+const escapeHtml = (text: string): string => {
+    return text
+        .replace(/&/g, '&amp;')
+        .replace(/</g, '&lt;')
+        .replace(/>/g, '&gt;')
+        .replace(/"/g, '&quot;')
+        .replace(/'/g, '&#x27;');
+};
+
+const mapNonFencedSegments = (markdown: string, mapSegment: (segment: string) => string): string => {
+    return markdown
+        .split(FENCED_CODE_SEGMENT_PATTERN)
+        .map((segment, index) => (index % 2 === 1 ? segment : mapSegment(segment)))
+        .join('');
+};
+
+// In Markdown a single "\n" is a soft break (rendered as a space). Users type plain
+// text where each newline is meant literally, so convert soft breaks into hard breaks
+// (two trailing spaces) outside of fenced code blocks, where newlines are already literal.
+const applyHardLineBreaks = (markdown: string): string => {
+    return mapNonFencedSegments(markdown, (segment) => segment.replace(/ *\n/g, '  \n'));
+};
+
+export const prepareUserMarkdownContent = ({
+    textContent,
+    agentMention,
+    skillNames,
+}: {
+    textContent: string;
+    agentMention?: AgentMentionInfo;
+    skillNames: ReadonlySet<string>;
+}): string => {
+    let content = mapNonFencedSegments(textContent, escapeHtml);
+
+    // Insert agent mention links with an internal href so markdown renders them as mentions, not external links.
+    if (agentMention?.token && content.includes(agentMention.token)) {
+        const mentionMarkdown = `[${agentMention.token}](${buildAgentHref(agentMention.name)})`;
+        content = content.replace(agentMention.token, mentionMarkdown);
+    }
+
+    content = content.replace(SKILL_TOKEN_PATTERN, (match, prefix: string, skillName: string) => {
+        if (!skillNames.has(skillName)) return match;
+        return `${prefix}[/${skillName}](${buildSkillHref(skillName)})`;
+    });
+
+    // Preserve user newlines (markdown soft breaks would otherwise collapse to spaces)
+    return applyHardLineBreaks(content);
+};