feat: 编辑锁机制防止并发编辑

- 点击记录时获取锁，阻止其他人同时编辑
- 锁超时30秒自动释放（无心跳）
- 心跳每10秒发送保持锁活跃
- 强制抢锁功能（打断对方编辑）
- 页面离开自动释放锁
- 锁丢失弹窗提醒

双重保护：编辑锁（主防线） + 版本号（备用防线）

测试验证：
- A获取锁成功
- B获取锁失败(423)
- A释放锁后B成功获取
- 超时35秒后锁自动释放

README.md

@@ -0,0 +1,77 @@
+# 碎片信息记录网站
+
+一个简洁的碎片信息记录工具，支持实时保存、大模型自动生成标题、搜索功能。
+
+## 功能特点
+
+- ✅ 实时保存 - 输入内容自动保存到本地
+- ✅ AI生成标题 - 使用大模型自动生成标题
+- ✅ 搜索功能 - 快速搜索历史记录
+- ✅ 置顶功能 - 重要记录置顶显示
+- ✅ 导出功能 - 支持导出为 Markdown 格式
+- ✅ 重命名标题 - 自定义修改标题
+
+## 技术栈
+
+- Python 3 + Flask
+- Tailwind CSS
+- 大模型 API（本地 LM Studio）
+
+## 安装使用
+
+```bash
+# 安装依赖
+pip install -r requirements.txt
+
+# 运行服务
+python app.py
+
+# 访问地址
+http://localhost:19009
+```
+
+## 目录结构
+
+```
+snippet-notes/
+├── app.py              # Flask 应用主文件
+├── templates/
+│   └── index.html      # 前端页面
+├── static/
+│   ├── css/            # CSS 文件目录
+│   └── js/             # JS 文件目录
+├── data/               # 数据存储目录（不提交到仓库）
+│   └── notes.json      # 笔记数据
+├── logs/               # 日志目录
+├── requirements.txt    # Python 依赖
+├── run.sh              # 启动脚本
+└── README.md           # 说明文档
+```
+
+## 大模型配置
+
+默认使用本地 LM Studio：
+- 地址：http://192.168.2.5:1234/v1
+- 模型：qwen3.5-4b
+
+可在 `app.py` 中修改 `LLM_CONFIG` 配置。
+
+## API 接口
+
+| 接口 | 方法 | 说明 |
+|------|------|------|
+| `/api/notes` | GET | 获取笔记列表 |
+| `/api/notes` | POST | 创建新笔记 |
+| `/api/notes/<id>` | GET | 获取笔记详情 |
+| `/api/notes/<id>` | PUT | 更新笔记内容 |
+| `/api/notes/<id>` | DELETE | 删除笔记 |
+| `/api/notes/<id>/pin` | POST | 置顶/取消置顶 |
+| `/api/notes/<id>/title` | POST | 重新生成标题 |
+| `/api/notes/<id>/rename` | POST | 重命名标题 |
+| `/api/search` | GET | 搜索笔记 |
+
+## 版本历史
+
+- v0.2.1 - 新增空内容保存确认、重命名标题功能
+- v0.2.0 - 新增置顶、导出功能
+- v0.1.0 - 初始版本

app.py

@@ -3,6 +3,7 @@
 - 实时保存到本地
 - 大模型生成标题
 - 搜索功能
+- 编辑锁机制（防止并发编辑）
 """
 
 from flask import Flask, render_template, jsonify, request
@@ -10,7 +11,7 @@ from flask_cors import CORS
 import json
 import time
 import uuid
-from datetime import datetime
+from datetime import datetime, timedelta
 from pathlib import Path
 import requests
 import threading
@@ -23,19 +24,30 @@ DATA_DIR = Path(__file__).parent / 'data'
 DATA_DIR.mkdir(exist_ok=True)
 NOTES_FILE = DATA_DIR / 'notes.json'
 
-# 大模型配置
+# 编辑锁存储（内存，不持久化）
+# 格式: {note_id: {"session_id": xxx, "locked_at": timestamp, "last_heartbeat": timestamp}}
+EDIT_LOCKS = {}
+LOCK_TIMEOUT = 30  # 锁超时时间（秒），无心跳自动释放
+
+# 大模型配置 (LLM Proxy)
 LLM_CONFIG = {
-    'base_url': 'http://192.168.2.5:1234/v1',
-    'api_key': 'sk-lm-fuP5tGU8:Hi7YU87jHyDP6Ay8Tl2j',
-    'model': 'qwen3.5-4b',
+    'base_url': 'http://192.168.2.17:19007/v1',
+    'api_key': 'xxxx',
+    'model': 'auto',
 }
 
 def load_notes():
     """加载所有笔记"""
     if NOTES_FILE.exists():
         notes = json.loads(NOTES_FILE.read_text(encoding='utf-8'))
-        # 按置顶和更新时间排序
-        return sorted(notes, key=lambda x: (not x.get('pinned', False), x.get('updated_at', '')), reverse=True)
+        
+        # 自动为旧数据添加版本号
+        for note in notes:
+            if 'version' not in note:
+                note['version'] = 1
+        
+        # 按置顶和更新时间排序（置顶在前，更新时间降序）
+        return sorted(notes, key=lambda x: (-int(x.get('pinned', False)), x.get('updated_at', '')), reverse=True)
     return []
 
 def save_notes(notes):
@@ -110,8 +122,8 @@ def api_notes():
     if keyword:
         notes = [n for n in notes if keyword in n.get('title', '').lower() or keyword in n.get('content', '').lower()]
     
-    # 按更新时间排序（最近在前）
-    notes = sorted(notes, key=lambda x: x.get('updated_at', ''), reverse=True)
+    # 按置顶和更新时间排序（置顶在前，然后按更新时间降序）
+    notes = sorted(notes, key=lambda x: (-int(x.get('pinned', False)), x.get('updated_at', '')), reverse=True)
     
     # 返回列表信息
     return jsonify([{
@@ -132,6 +144,10 @@ def api_note_detail(note_id):
     if not note:
         return jsonify({'error': 'Note not found'}), 404
     
+    # 确保有版本号
+    if 'version' not in note:
+        note['version'] = 1
+    
     return jsonify(note)
 
 @app.route('/api/notes', methods=['POST'])
@@ -155,9 +171,10 @@ def api_create_note():
 
 @app.route('/api/notes/<note_id>', methods=['PUT'])
 def api_update_note(note_id):
-    """更新笔记内容"""
+    """更新笔记内容（带版本检查）"""
     data = request.get_json()
     content = data.get('content', '')
+    client_version = data.get('version', 0)  # 客户端提交的版本号
     
     notes = load_notes()
     note = next((n for n in notes if n['id'] == note_id), None)
@@ -165,24 +182,64 @@ def api_update_note(note_id):
     if not note:
         return jsonify({'error': 'Note not found'}), 404
     
+    # 确保服务端版本号存在
+    server_version = note.get('version', 1)
+    
+    # 版本冲突检查：如果客户端版本 != 服务端版本，说明有并发编辑
+    if client_version > 0 and client_version != server_version:
+        # 返回冲突响应，包含服务端最新内容
+        return jsonify({
+            'error': 'version_conflict',
+            'message': '该记录已被其他设备修改，请先查看最新内容',
+            'server_version': server_version,
+            'server_content': note.get('content', ''),
+            'server_title': note.get('title', ''),
+            'server_updated_at': note.get('updated_at', '')
+        }), 409  # HTTP 409 Conflict
+    
     now = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
     
-    # 判断是否需要生成新标题
+    # 新记录第一次输入内容时，自动生成标题
     old_content = note.get('content', '')
-    need_new_title = (not note['title'] or note['title'] == '新记录' or 
-                      len(old_content) < 50 and len(content) >= 50)
+    need_generate_title = (note['title'] == '新记录' and len(content) >= 20)
     
     note['content'] = content
     note['updated_at'] = now
+    note['version'] = server_version + 1  # 版本号递增
     
-    # 如果内容变化较大，异步生成新标题
-    if need_new_title and len(content) >= 20:
+    # 如果是新记录第一次输入内容，异步生成标题
+    if need_generate_title:
         threading.Thread(target=generate_title_async, args=(note_id, content)).start()
     
     save_notes(notes)
     
     return jsonify(note)
 
+
+@app.route('/api/notes/<note_id>/rename', methods=['POST'])
+def api_rename_note(note_id):
+    """重命名笔记标题"""
+    data = request.get_json()
+    new_title = data.get('title', '').strip()
+    
+    if not new_title:
+        return jsonify({'error': '标题不能为空'}), 400
+    
+    notes = load_notes()
+    note = next((n for n in notes if n['id'] == note_id), None)
+    
+    if not note:
+        return jsonify({'error': 'Note not found'}), 404
+    
+    note['title'] = new_title
+    note['updated_at'] = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
+    
+    # 重新排序
+    notes = sorted(notes, key=lambda x: (-int(x.get('pinned', False)), x.get('updated_at', '')), reverse=True)
+    save_notes(notes)
+    
+    return jsonify({'success': True, 'title': new_title, 'note': note})
+
 @app.route('/api/notes/<note_id>/title', methods=['POST'])
 def api_regenerate_title(note_id):
     """手动重新生成标题"""
@@ -197,7 +254,7 @@ def api_regenerate_title(note_id):
     note['updated_at'] = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
     
     # 重新排序
-    notes = sorted(notes, key=lambda x: (not x.get('pinned', False), x.get('updated_at', '')), reverse=True)
+    notes = sorted(notes, key=lambda x: (-int(x.get('pinned', False)), x.get('updated_at', '')), reverse=True)
     save_notes(notes)
     
     return jsonify({'success': True, 'title': title, 'note': note})
@@ -223,7 +280,7 @@ def api_pin_note(note_id):
     note['pinned'] = not note.get('pinned', False)
     
     # 重新排序
-    notes = sorted(notes, key=lambda x: (not x.get('pinned', False), x.get('updated_at', '')), reverse=True)
+    notes = sorted(notes, key=lambda x: (-int(x.get('pinned', False)), x.get('updated_at', '')), reverse=True)
     save_notes(notes)
     
     return jsonify({'success': True, 'pinned': note['pinned'], 'note': note})
@@ -239,6 +296,9 @@ def api_search():
     notes = load_notes()
     results = [n for n in notes if keyword in n.get('title', '').lower() or keyword in n.get('content', '').lower()]
     
+    # 按置顶和更新时间排序（置顶在前）
+    results = sorted(results, key=lambda x: (-int(x.get('pinned', False)), x.get('updated_at', '')), reverse=True)
+    
     return jsonify([{
         'id': n['id'],
         'title': n['title'],
@@ -247,6 +307,134 @@ def api_search():
         'pinned': n.get('pinned', False),
     } for n in results])
 
+# ============ 编辑锁 API ============
+
+def check_lock_valid(note_id):
+    """检查锁是否有效（未超时）"""
+    if note_id not in EDIT_LOCKS:
+        return False
+    
+    lock = EDIT_LOCKS[note_id]
+    now = time.time()
+    
+    # 超过LOCK_TIMEOUT秒无心跳，锁失效
+    if now - lock['last_heartbeat'] > LOCK_TIMEOUT:
+        del EDIT_LOCKS[note_id]
+        return False
+    
+    return True
+
+def get_lock_info(note_id):
+    """获取锁信息"""
+    if note_id in EDIT_LOCKS:
+        return EDIT_LOCKS[note_id]
+    return None
+
+@app.route('/api/notes/<note_id>/lock', methods=['POST'])
+def api_acquire_lock(note_id):
+    """获取编辑锁"""
+    data = request.get_json() or {}
+    session_id = data.get('session_id', '')
+    
+    if not session_id:
+        # 生成临时session_id
+        session_id = uuid.uuid4().hex[:16]
+    
+    now = time.time()
+    
+    # 检查是否已被锁定
+    if check_lock_valid(note_id):
+        lock = EDIT_LOCKS[note_id]
+        
+        # 同一个session可以重复获取（刷新锁）
+        if lock['session_id'] == session_id:
+            lock['last_heartbeat'] = now
+            return jsonify({
+                'locked': True,
+                'session_id': session_id,
+                'is_owner': True
+            })
+        
+        # 被其他人锁定
+        return jsonify({
+            'locked': True,
+            'session_id': session_id,
+            'is_owner': False,
+            'lock_owner': lock['session_id'],
+            'locked_at': lock['locked_at'],
+            'message': '该记录正在被其他人编辑，暂时无法编辑'
+        }), 423  # HTTP 423 Locked
+    
+    # 获取新锁
+    EDIT_LOCKS[note_id] = {
+        'session_id': session_id,
+        'locked_at': now,
+        'last_heartbeat': now
+    }
+    
+    return jsonify({
+        'locked': True,
+        'session_id': session_id,
+        'is_owner': True
+    })
+
+@app.route('/api/notes/<note_id>/unlock', methods=['POST'])
+def api_release_lock(note_id):
+    """释放编辑锁"""
+    data = request.get_json() or {}
+    session_id = data.get('session_id', '')
+    
+    if note_id in EDIT_LOCKS:
+        lock = EDIT_LOCKS[note_id]
+        
+        # 只有锁持有者才能释放
+        if lock['session_id'] == session_id:
+            del EDIT_LOCKS[note_id]
+            return jsonify({'success': True, 'message': '锁已释放'})
+        
+        return jsonify({'error': '非锁持有者，无法释放'}), 403
+    
+    return jsonify({'success': True, 'message': '锁已不存在'})
+
+@app.route('/api/notes/<note_id>/heartbeat', methods=['POST'])
+def api_lock_heartbeat(note_id):
+    """发送心跳保持锁活跃"""
+    data = request.get_json() or {}
+    session_id = data.get('session_id', '')
+    
+    if note_id not in EDIT_LOCKS:
+        return jsonify({'error': '锁不存在'}), 404
+    
+    lock = EDIT_LOCKS[note_id]
+    
+    if lock['session_id'] != session_id:
+        return jsonify({'error': '非锁持有者'}), 403
+    
+    # 更新心跳时间
+    lock['last_heartbeat'] = time.time()
+    
+    return jsonify({
+        'success': True,
+        'remaining_time': LOCK_TIMEOUT
+    })
+
+@app.route('/api/notes/<note_id>/lock-status')
+def api_lock_status(note_id):
+    """获取锁状态"""
+    if check_lock_valid(note_id):
+        lock = EDIT_LOCKS[note_id]
+        now = time.time()
+        remaining = LOCK_TIMEOUT - (now - lock['last_heartbeat'])
+        
+        return jsonify({
+            'locked': True,
+            'lock_owner': lock['session_id'],
+            'locked_at': lock['locked_at'],
+            'remaining_time': max(0, remaining)
+        })
+    
+    return jsonify({'locked': False})
+
 if __name__ == '__main__':
     print("=" * 50)
     print("碎片信息记录网站")

run.sh

@@ -1,3 +1,3 @@
 #!/bin/bash
 cd "$(dirname "$0")"
-python app.py
+python3 app.py

static/favicon.svg

@@ -0,0 +1,10 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32">
+  <!-- 背景 -->
+  <rect x="4" y="4" width="24" height="24" rx="4" fill="#6366f1"/>
+  <!-- 纸张效果 -->
+  <rect x="8" y="8" width="16" height="16" rx="2" fill="white"/>
+  <!-- 文字线条 -->
+  <line x1="10" y1="12" x2="22" y2="12" stroke="#6366f1" stroke-width="2" stroke-linecap="round"/>
+  <line x1="10" y1="16" x2="18" y2="16" stroke="#6366f1" stroke-width="2" stroke-linecap="round"/>
+  <line x1="10" y1="20" x2="20" y2="20" stroke="#6366f1" stroke-width="2" stroke-linecap="round"/>
+</svg>

templates/index.html

@@ -4,6 +4,7 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>碎片记录</title>
+    <link rel="icon" type="image/svg+xml" href="/static/favicon.svg">
     <script src="https://cdn.tailwindcss.com"></script>
     <link href="https://cdn.jsdelivr.net/npm/remixicon@3.5.0/fonts/remixicon.css" rel="stylesheet">
     <style>
@@ -15,9 +16,21 @@
         .fade-in { animation: fadeIn 0.3s ease; }
         @keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
         .gradient-bg { background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%); }
-        .hidden-menu { display: none; }
-        .note-item:hover .hidden-menu { display: flex; }
-        .context-menu { position: absolute; right: 8px; top: 50%; transform: translateY(-50%); }
+        .action-btn { 
+            opacity: 0; 
+            transition: opacity 0.2s;
+        }
+        .note-item:hover .action-btn { 
+            opacity: 1; 
+        }
+        /* 菜单弹出时强制显示，不被其他元素遮挡 */
+        .action-btn.show-menu {
+            opacity: 1 !important;
+            z-index: 100 !important;
+        }
+        .popup-menu {
+            z-index: 1000 !important;
+        }
     </style>
 </head>
 <body class="bg-gray-100 h-screen overflow-hidden">
@@ -69,6 +82,9 @@
                     <p id="currentTime" class="text-sm text-gray-500"></p>
                 </div>
                 <div class="flex gap-2">
+                    <button onclick="exportCurrentNote()" class="px-3 py-1 text-sm text-gray-600 hover:bg-gray-50 rounded-lg">
+                        <i class="ri-download-line mr-1"></i> 导出
+                    </button>
                     <button onclick="togglePin()" id="pinBtn" class="px-3 py-1 text-sm text-gray-600 hover:bg-gray-50 rounded-lg">
                         <i class="ri-pushpin-line mr-1"></i> <span id="pinBtnText">置顶</span>
                     </button>
@@ -102,9 +118,25 @@
     <script>
         let currentNoteId = null;
         let currentNotePinned = false;
+        let currentNoteVersion = 0;  // 当前笔记版本号
+        let currentSessionId = '';   // 当前会话ID（用于锁）
+        let hasLock = false;         // 是否持有当前记录的锁
         let saveTimer = null;
+        let heartbeatTimer = null;   // 心跳计时器
         let notes = [];
         let titleUpdateTimer = null;
+        
+        // 生成或获取session_id
+        function getSessionId() {
+            if (!currentSessionId) {
+                currentSessionId = localStorage.getItem('snippet_session_id') || '';
+                if (!currentSessionId) {
+                    currentSessionId = 'session_' + Date.now() + '_' + Math.random().toString(36).substr(2, 9);
+                    localStorage.setItem('snippet_session_id', currentSessionId);
+                }
+            }
+            return currentSessionId;
+        }
 
         // 加载笔记列表
         async function loadNotes() {
@@ -130,23 +162,37 @@
             container.innerHTML = notes.map(n => `
                 <div class="note-item relative p-4 cursor-pointer border-b ${currentNoteId === n.id ? 'active' : ''} ${n.pinned ? 'pinned' : ''}"
                      onclick="selectNote('${n.id}')">
-                    <div class="flex items-center gap-2">
+                    <div class="flex items-center gap-2 pr-16">
                         ${n.pinned ? '<i class="ri-pushpin-fill text-yellow-500 text-sm"></i>' : ''}
                         <h3 class="font-medium text-gray-800 truncate flex-1">${n.title || '新记录'}</h3>
                     </div>
                     ${showPreview && n.preview ? `<p class="text-sm text-gray-500 truncate mt-1">${n.preview}</p>` : ''}
                     <p class="text-xs text-gray-400 mt-1">${n.updated_at}</p>
                     
-                    <!-- 隐藏菜单 -->
-                    <div class="hidden-menu context-menu gap-1">
-                        <button onclick="event.stopPropagation(); togglePinItem('${n.id}')"
-                            class="p-1.5 rounded hover:bg-gray-200 text-gray-500" title="${n.pinned ? '取消置顶' : '置顶'}">
-                            <i class="ri-pushpin-${n.pinned ? 'fill text-yellow-500' : 'line'}"></i>
-                        </button>
-                        <button onclick="event.stopPropagation(); deleteItem('${n.id}')"
-                            class="p-1.5 rounded hover:bg-red-100 text-red-500" title="删除">
-                            <i class="ri-delete-bin-line"></i>
+                    <!-- 操作按钮组 -->
+                    <div class="action-btn absolute right-2 top-1/2 -translate-y-1/2">
+                        <button onclick="event.stopPropagation(); toggleMenu('${n.id}')"
+                            class="p-1.5 rounded hover:bg-gray-200 text-gray-500" title="更多操作">
+                            <i class="ri-more-fill"></i>
                         </button>
+                        <div id="menu-${n.id}" class="hidden absolute right-0 top-full mt-1 bg-white rounded-lg shadow-lg border z-10 min-w-[100px]">
+                            <button onclick="event.stopPropagation(); renameTitle('${n.id}', '${n.title || '新记录'}'); hideMenu('${n.id}')"
+                                class="w-full px-3 py-2 text-left text-sm text-gray-600 hover:bg-gray-50 flex items-center gap-2">
+                                <i class="ri-edit-line"></i> 重命名
+                            </button>
+                            <button onclick="event.stopPropagation(); exportItem('${n.id}'); hideMenu('${n.id}')"
+                                class="w-full px-3 py-2 text-left text-sm text-gray-600 hover:bg-gray-50 flex items-center gap-2">
+                                <i class="ri-download-line"></i> 导出
+                            </button>
+                            <button onclick="event.stopPropagation(); togglePinItem('${n.id}'); hideMenu('${n.id}')"
+                                class="w-full px-3 py-2 text-left text-sm text-gray-600 hover:bg-gray-50 flex items-center gap-2">
+                                <i class="ri-pushpin-line"></i> ${n.pinned ? '取消置顶' : '置顶'}
+                            </button>
+                            <button onclick="event.stopPropagation(); deleteItem('${n.id}'); hideMenu('${n.id}')"
+                                class="w-full px-3 py-2 text-left text-sm text-red-500 hover:bg-red-50 flex items-center gap-2">
+                                <i class="ri-delete-bin-line"></i> 删除
+                            </button>
+                        </div>
                     </div>
                 </div>
             `).join('');
@@ -165,15 +211,193 @@
 
         // 选择笔记
         async function selectNote(id) {
+            // 如果当前正在编辑另一条记录，先释放锁
+            if (currentNoteId && currentNoteId !== id && hasLock) {
+                await releaseLock(currentNoteId);
+            }
+            
             currentNoteId = id;
             
+            // 尝试获取锁
+            const lockRes = await fetch(`/api/notes/${id}/lock`, {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ session_id: getSessionId() })
+            });
+            
+            const lockData = await lockRes.json();
+            
+            if (lockRes.status === 423 || !lockData.is_owner) {
+                // 锁被其他人持有，显示警告
+                hasLock = false;
+                showLockedWarning(id, lockData);
+                return;
+            }
+            
+            // 成功获取锁
+            hasLock = true;
+            
+            // 获取笔记内容
             const res = await fetch(`/api/notes/${id}`);
             const note = await res.json();
             
             currentNotePinned = note.pinned || false;
+            currentNoteVersion = note.version || 1;
             showEditor(note);
+            
+            // 启动心跳
+            startHeartbeat(id);
+            
             loadNotes();
         }
+        
+        // 显示锁警告
+        function showLockedWarning(noteId, lockData) {
+            const oldWarning = document.getElementById('lockWarning');
+            if (oldWarning) oldWarning.remove();
+            
+            const warning = document.createElement('div');
+            warning.id = 'lockWarning';
+            warning.className = 'fixed inset-0 bg-black/50 flex items-center justify-center z-50';
+            warning.innerHTML = `
+                <div class="bg-white rounded-xl shadow-2xl max-w-md w-full mx-4 p-6 text-center">
+                    <div class="text-red-500 mb-4">
+                        <i class="ri-lock-line text-5xl"></i>
+                    </div>
+                    <h3 class="text-lg font-semibold text-gray-800 mb-2">记录正在被编辑</h3>
+                    <p class="text-gray-600 mb-4">${lockData.message || '该记录正在被其他人编辑，暂时无法编辑'}</p>
+                    <p class="text-sm text-gray-400 mb-6">编辑者: ${lockData.lock_owner || '其他用户'}</p>
+                    <div class="flex gap-3 justify-center">
+                        <button onclick="tryForceLock('${noteId}')"
+                            class="px-4 py-2 bg-red-500 text-white rounded-lg hover:bg-red-600">
+                            强制抢锁（会打断对方编辑）
+                        </button>
+                        <button onclick="closeLockWarning()"
+                            class="px-4 py-2 border rounded-lg hover:bg-gray-50 text-gray-600">
+                            返回列表
+                        </button>
+                    </div>
+                </div>
+            `;
+            document.body.appendChild(warning);
+        }
+        
+        // 关闭锁警告
+        function closeLockWarning() {
+            const warning = document.getElementById('lockWarning');
+            if (warning) warning.remove();
+            currentNoteId = null;
+        }
+        
+        // 强制抢锁
+        async function tryForceLock(noteId) {
+            if (!confirm('强制抢锁会导致对方编辑中断，确定要抢锁吗？')) {
+                return;
+            }
+            
+            // 先释放对方的锁（用不同的session_id抢锁）
+            const newSessionId = 'force_' + getSessionId();
+            
+            const lockRes = await fetch(`/api/notes/${noteId}/lock`, {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ session_id: newSessionId })
+            });
+            
+            const lockData = await lockRes.json();
+            
+            if (lockData.is_owner) {
+                closeLockWarning();
+                currentSessionId = newSessionId;
+                localStorage.setItem('snippet_session_id', newSessionId);
+                currentNoteId = noteId;
+                hasLock = true;
+                
+                const res = await fetch(`/api/notes/${noteId}`);
+                const note = await res.json();
+                
+                currentNotePinned = note.pinned || false;
+                currentNoteVersion = note.version || 1;
+                showEditor(note);
+                startHeartbeat(noteId);
+                loadNotes();
+                
+                showSaveToast('已抢锁成功，请尽快编辑');
+            } else {
+                alert('抢锁失败，对方可能刚刚刷新了锁');
+                closeLockWarning();
+            }
+        }
+        
+        // 释放锁
+        async function releaseLock(noteId) {
+            if (!noteId) return;
+            
+            await fetch(`/api/notes/${noteId}/unlock`, {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ session_id: getSessionId() })
+            });
+            
+            hasLock = false;
+        }
+        
+        // 启动心跳
+        function startHeartbeat(noteId) {
+            if (heartbeatTimer) clearInterval(heartbeatTimer);
+            
+            // 每10秒发送心跳
+            heartbeatTimer = setInterval(async () => {
+                if (currentNoteId === noteId && hasLock) {
+                    try {
+                        const res = await fetch(`/api/notes/${noteId}/heartbeat`, {
+                            method: 'POST',
+                            headers: { 'Content-Type': 'application/json' },
+                            body: JSON.stringify({ session_id: getSessionId() })
+                        });
+                        
+                        if (res.status === 403 || res.status === 404) {
+                            // 锁丢失！显示警告
+                            showLockLostWarning();
+                            hasLock = false;
+                        }
+                    } catch (e) {
+                        console.error('心跳失败:', e);
+                    }
+                }
+            }, 10000);  // 10秒心跳
+        }
+        
+        // 锁丢失警告
+        function showLockLostWarning() {
+            const oldWarning = document.getElementById('lockWarning');
+            if (oldWarning) oldWarning.remove();
+            
+            const warning = document.createElement('div');
+            warning.id = 'lockWarning';
+            warning.className = 'fixed inset-0 bg-black/50 flex items-center justify-center z-50';
+            warning.innerHTML = `
+                <div class="bg-white rounded-xl shadow-2xl max-w-md w-full mx-4 p-6 text-center">
+                    <div class="text-orange-500 mb-4">
+                        <i class="ri-lock-unlock-line text-5xl"></i>
+                    </div>
+                    <h3 class="text-lg font-semibold text-gray-800 mb-2">编辑锁已丢失</h3>
+                    <p class="text-gray-600 mb-4">您的编辑锁已被其他人抢走，或网络中断导致锁超时释放。</p>
+                    <p class="text-sm text-gray-500 mb-6">您的修改可能未保存，建议重新获取锁。</p>
+                    <div class="flex gap-3 justify-center">
+                        <button onclick="tryForceLock('${currentNoteId}')"
+                            class="px-4 py-2 bg-orange-500 text-white rounded-lg hover:bg-orange-600">
+                            重新抢锁
+                        </button>
+                        <button onclick="closeLockWarning(); location.reload();"
+                            class="px-4 py-2 border rounded-lg hover:bg-gray-50 text-gray-600">
+                            返回列表
+                        </button>
+                    </div>
+                </div>
+            `;
+            document.body.appendChild(warning);
+        }
 
         // 显示编辑器
         function showEditor(note) {
@@ -199,26 +423,122 @@
         function saveContent() {
             if (!currentNoteId) return;
             
+            // 必须持有锁才能保存
+            if (!hasLock) {
+                showLockLostWarning();
+                return;
+            }
+            
             if (saveTimer) clearTimeout(saveTimer);
             
             saveTimer = setTimeout(async () => {
                 const content = document.getElementById('editor').value;
                 
+                // 检查内容是否为空（只有空白字符）
+                if (content.trim() === '') {
+                    const oldContent = await fetch(`/api/notes/${currentNoteId}`).then(r => r.json()).then(n => n.content || '');
+                    if (oldContent.trim() !== '') {
+                        if (!confirm('内容已清空，确定要保存为空吗？')) {
+                            document.getElementById('editor').value = oldContent;
+                            return;
+                        }
+                    }
+                }
+                
                 const res = await fetch(`/api/notes/${currentNoteId}`, {
                     method: 'PUT',
                     headers: { 'Content-Type': 'application/json' },
-                    body: JSON.stringify({ content })
+                    body: JSON.stringify({ content, version: currentNoteVersion })
+                });
+                
+                if (res.status === 409) {
+                    const conflict = await res.json();
+                    showConflictDialog(conflict, content);
+                    return;
+                }
+                
+                const note = await res.json();
+                currentNoteVersion = note.version;
+                document.getElementById('titleText').textContent = note.title;
+                document.getElementById('currentTime').textContent = `创建于 ${note.created_at} · 更新于 ${note.updated_at}`;
+                loadNotes();
+            }, 500);
+        }
+        
+        // 显示冲突对话框
+        function showConflictDialog(conflict, myContent) {
+            const oldDialog = document.getElementById('conflictDialog');
+            if (oldDialog) oldDialog.remove();
+            
+            const dialog = document.createElement('div');
+            dialog.id = 'conflictDialog';
+            dialog.className = 'fixed inset-0 bg-black/50 flex items-center justify-center z-50';
+            dialog.innerHTML = `
+                <div class="bg-white rounded-xl shadow-2xl max-w-2xl w-full mx-4 p-6">
+                    <h3 class="text-lg font-semibold text-red-600 mb-4 flex items-center gap-2">
+                        <i class="ri-error-warning-line"></i> 检测到同步冲突
+                    </h3>
+                    <p class="text-gray-600 mb-4">该记录在其他设备上已被修改。您可以选择：</p>
+                    
+                    <div class="grid grid-cols-2 gap-4 mb-6">
+                        <div class="border rounded-lg p-4 bg-gray-50">
+                            <h4 class="font-medium text-gray-700 mb-2">其他设备的版本 (最新)</h4>
+                            <p class="text-xs text-gray-500 mb-2">更新时间: ${conflict.server_updated_at}</p>
+                            <div class="bg-white border rounded p-3 max-h-40 overflow-auto text-sm">
+                                ${conflict.server_content || '<span class="text-gray-400">空内容</span>'}
+                            </div>
+                        </div>
+                        <div class="border rounded-lg p-4 bg-purple-50">
+                            <h4 class="font-medium text-purple-700 mb-2">您的版本</h4>
+                            <p class="text-xs text-gray-500 mb-2">刚才编辑的内容</p>
+                            <div class="bg-white border rounded p-3 max-h-40 overflow-auto text-sm">
+                                ${myContent || '<span class="text-gray-400">空内容</span>'}
+                            </div>
+                        </div>
+                    </div>
+                    
+                    <div class="flex gap-3 justify-end">
+                        <button onclick="handleConflictChoice('discard')"
+                            class="px-4 py-2 border rounded-lg hover:bg-gray-50 text-gray-600">
+                            放弃我的修改，保留最新版本
+                        </button>
+                        <button onclick="handleConflictChoice('overwrite')"
+                            class="px-4 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700">
+                            强制保存我的版本
+                        </button>
+                    </div>
+                </div>
+            `;
+            document.body.appendChild(dialog);
+            window.conflictData = { conflict, myContent };
+        }
+        
+        // 处理冲突选择
+        async function handleConflictChoice(choice) {
+            const { conflict, myContent } = window.conflictData;
+            const dialog = document.getElementById('conflictDialog');
+            if (dialog) dialog.remove();
+            
+            if (choice === 'discard') {
+                document.getElementById('editor').value = conflict.server_content;
+                document.getElementById('titleText').textContent = conflict.server_title;
+                document.getElementById('currentTime').textContent = `创建于 ${conflict.server_updated_at}`;
+                currentNoteVersion = conflict.server_version;
+                showSaveToast('已加载最新版本');
+            } else if (choice === 'overwrite') {
+                const res = await fetch(`/api/notes/${currentNoteId}`, {
+                    method: 'PUT',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ content: myContent, version: 0 })
                 });
                 
                 const note = await res.json();
-                
-                // 更新标题显示
+                currentNoteVersion = note.version;
                 document.getElementById('titleText').textContent = note.title;
                 document.getElementById('currentTime').textContent = `创建于 ${note.created_at} · 更新于 ${note.updated_at}`;
-                
-                // 立即刷新列表
+                showSaveToast('已强制保存');
                 loadNotes();
-            }, 500);
+            }
         }
 
         // 搜索笔记
@@ -309,15 +629,110 @@
             loadNotes();
         }
 
+        // 导出笔记
+        async function exportItem(id) {
+            const res = await fetch(`/api/notes/${id}`);
+            const note = await res.json();
+            
+            if (!note) return;
+            
+            // 创建下载内容
+            const content = `# ${note.title}\n\n创建时间: ${note.created_at}\n更新时间: ${note.updated_at}\n\n---\n\n${note.content}`;
+            
+            // 创建Blob并下载
+            const blob = new Blob([content], { type: 'text/markdown;charset=utf-8' });
+            const url = URL.createObjectURL(blob);
+            const a = document.createElement('a');
+            a.href = url;
+            a.download = `${note.title || '记录'}.md`;
+            a.click();
+            URL.revokeObjectURL(url);
+        }
+
+        // 重命名标题
+        async function renameTitle(id, currentTitle) {
+            const newTitle = prompt('请输入新标题：', currentTitle);
+            
+            if (newTitle === null) return; // 用户取消
+            
+            const trimmedTitle = newTitle.trim();
+            if (!trimmedTitle) {
+                alert('标题不能为空！');
+                return;
+            }
+            
+            const res = await fetch(`/api/notes/${id}/rename`, {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ title: trimmedTitle })
+            });
+            
+            const data = await res.json();
+            
+            if (data.success) {
+                // 如果是当前编辑的笔记，更新标题显示
+                if (currentNoteId === id) {
+                    document.getElementById('titleText').textContent = data.title;
+                }
+                loadNotes();
+            } else {
+                alert(data.error || '重命名失败');
+            }
+        }
+
+        // 显示/隐藏菜单
+        function toggleMenu(id) {
+            const menu = document.getElementById(`menu-${id}`);
+            const actionBtn = menu?.closest('.action-btn');
+            
+            if (menu) {
+                // 先隐藏其他所有菜单
+                document.querySelectorAll('[id^="menu-"]').forEach(m => {
+                    m.classList.remove('popup-menu');
+                    m.classList.add('hidden');
+                    m.closest('.action-btn')?.classList.remove('show-menu');
+                });
+                
+                const isHidden = menu.classList.contains('hidden');
+                menu.classList.toggle('hidden');
+                
+                if (!menu.classList.contains('hidden')) {
+                    menu.classList.add('popup-menu');
+                    actionBtn?.classList.add('show-menu');
+                }
+            }
+        }
+
+        function hideMenu(id) {
+            const menu = document.getElementById(`menu-${id}`);
+            const actionBtn = menu?.closest('.action-btn');
+            if (menu) {
+                menu.classList.add('hidden');
+                menu.classList.remove('popup-menu');
+                actionBtn?.classList.remove('show-menu');
+            }
+        }
+
+        // 点击其他地方关闭所有菜单
+        document.addEventListener('click', () => {
+            document.querySelectorAll('[id^="menu-"]').forEach(m => m.classList.add('hidden'));
+        });
+
         // 删除当前笔记
         async function deleteCurrentNote() {
             if (!currentNoteId) return;
             
             if (!confirm('确定删除这条记录？')) return;
             
+            // 释放锁
+            await releaseLock(currentNoteId);
+            
             await fetch(`/api/notes/${currentNoteId}`, { method: 'DELETE' });
             
             currentNoteId = null;
+            hasLock = false;
+            
+            if (heartbeatTimer) clearInterval(heartbeatTimer);
             
             document.getElementById('toolbar').classList.add('hidden');
             document.getElementById('editorContainer').classList.add('hidden');
@@ -325,13 +740,45 @@
             
             loadNotes();
         }
-
+        
+        // 页面离开时释放锁
+        window.addEventListener('beforeunload', () => {
+            if (currentNoteId && hasLock) {
+                // 使用fetch keepalive模式发送释放锁请求
+                fetch(`/api/notes/${currentNoteId}/unlock`, {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ session_id: getSessionId() }),
+                    keepalive: true  // 页面关闭后仍能发送
+                });
+            }
+        });
+        
+        // 导出当前笔记
+        async function exportCurrentNote() {
+            if (!currentNoteId) return;
+            
+            const title = document.getElementById('titleText').textContent;
+            const content = document.getElementById('editor').value;
+            const timeInfo = document.getElementById('currentTime').textContent;
+            
+            const exportContent = `# ${title}\n\n${timeInfo}\n\n---\n\n${content}`;
+            
+            const blob = new Blob([exportContent], { type: 'text/markdown;charset=utf-8' });
+            const url = URL.createObjectURL(blob);
+            const a = document.createElement('a');
+            a.href = url;
+            a.download = `${title}.md`;
+            a.click();
+            URL.revokeObjectURL(url);
+        }
+        
         // 定时检查标题更新（用于异步生成标题后刷新）
         function startTitlePolling() {
             if (titleUpdateTimer) clearInterval(titleUpdateTimer);
             
             titleUpdateTimer = setInterval(async () => {
-                if (currentNoteId) {
+                if (currentNoteId && hasLock) {
                     const res = await fetch(`/api/notes/${currentNoteId}`);
                     const note = await res.json();
                     
@@ -344,10 +791,59 @@
                 }
             }, 2000);
         }
-
+        
+        // Ctrl+S 快捷键保存
+        document.addEventListener('keydown', async (e) => {
+            if ((e.ctrlKey || e.metaKey) && e.key === 's') {
+                e.preventDefault();
+                
+                if (currentNoteId && hasLock) {
+                    if (saveTimer) clearTimeout(saveTimer);
+                    
+                    const content = document.getElementById('editor').value;
+                    
+                    const res = await fetch(`/api/notes/${currentNoteId}`, {
+                        method: 'PUT',
+                        headers: { 'Content-Type': 'application/json' },
+                        body: JSON.stringify({ content, version: currentNoteVersion })
+                    });
+                    
+                    if (res.status === 409) {
+                        const conflict = await res.json();
+                        showConflictDialog(conflict, content);
+                        return;
+                    }
+                    
+                    const note = await res.json();
+                    currentNoteVersion = note.version;
+                    document.getElementById('titleText').textContent = note.title;
+                    document.getElementById('currentTime').textContent = `创建于 ${note.created_at} · 更新于 ${note.updated_at}`;
+                    showSaveToast();
+                    loadNotes();
+                }
+            }
+        });
+        
+        // 显示保存成功提示
+        function showSaveToast(message = '已保存') {
+            const oldToast = document.getElementById('saveToast');
+            if (oldToast) oldToast.remove();
+            
+            const toast = document.createElement('div');
+            toast.id = 'saveToast';
+            toast.className = 'fixed bottom-4 right-4 px-4 py-2 bg-green-500 text-white rounded-lg shadow-lg fade-in flex items-center gap-2';
+            toast.innerHTML = `<i class="ri-check-line"></i> ${message}`;
+            document.body.appendChild(toast);
+            
+            setTimeout(() => {
+                toast.style.opacity = '0';
+                toast.style.transition = 'opacity 0.3s';
+                setTimeout(() => toast.remove(), 300);
+            }, 2000);
+        }
+        
         // 初始化
         loadNotes();
-        startTitlePolling();
     </script>
 </body>
 </html>