From 78df2249cf20a6f5ccc1c3e907331e6ea9fa8cda Mon Sep 17 00:00:00 2001
From: JOJO <1498581755@qq.com>
Date: Sun, 12 Apr 2026 19:59:28 +0800
Subject: [PATCH] fix: stabilize markdown code block selection and copy

---
 static/src/composables/useMarkdownRenderer.ts | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/static/src/composables/useMarkdownRenderer.ts b/static/src/composables/useMarkdownRenderer.ts
index 5b66a05..b37bca7 100644
--- a/static/src/composables/useMarkdownRenderer.ts
+++ b/static/src/composables/useMarkdownRenderer.ts
@@ -5,6 +5,18 @@ import renderMathInElement from 'katex/contrib/auto-render';
 let latexRenderTimer: number | null = null;
 const markdownCache = new Map<string, string>();
 
+function stableHash(input: string): string {
+  let hash = 5381;
+  for (let i = 0; i < input.length; i += 1) {
+    hash = (hash * 33) ^ input.charCodeAt(i);
+  }
+  return (hash >>> 0).toString(36);
+}
+
+function buildCacheKey(text: string): string {
+  return `md_${text.length}_${stableHash(text)}`;
+}
+
 function wrapCodeBlocks(html: string, isStreaming = false) {
   if (isStreaming) {
     return html;
@@ -16,7 +28,7 @@ function wrapCodeBlocks(html: string, isStreaming = false) {
     (match, attributes, content) => {
       const langMatch = attributes.match(/class="[^"]*language-(\w+)/);
       const language = langMatch ? langMatch[1] : 'text';
-      const blockId = `code-${Date.now()}-${counter++}`;
+      const blockId = `code-${stableHash(`${attributes}|${content}|${counter++}`)}`;
       const escapedContent = content
         .replace(/&/g, '&amp;')
         .replace(/</g, '&lt;')
@@ -50,7 +62,7 @@ export function renderMarkdown(text: string, isStreaming = false) {
   });
 
   if (!isStreaming) {
-    const cacheKey = `${text.length}_${text.substring(0, 100)}`;
+    const cacheKey = buildCacheKey(text);
     if (markdownCache.has(cacheKey)) {
       return markdownCache.get(cacheKey) as string;
     }
@@ -61,7 +73,7 @@ export function renderMarkdown(text: string, isStreaming = false) {
   html = wrapCodeBlocks(html, isStreaming);
 
   if (!isStreaming && text.length < 10000) {
-    const cacheKey = `${text.length}_${text.substring(0, 100)}`;
+    const cacheKey = buildCacheKey(text);
     markdownCache.set(cacheKey, html);
     if (markdownCache.size > 20) {
       const firstKey = markdownCache.keys().next().value as string | undefined;