refactor: state 管理优化 - 结构化浅比较 + update/setIn/batch API

- state.js: 新增 shallowEqual、update()、setIn()、batch() 方法
- input-area.js: messages.push() 全部改为 state.update()，确保引用变化触发通知
- model-bar.js: 直接属性赋值改为 state.update()，修复 model 切换不触发变更检测

js/components/input-area.js

@@ -345,15 +345,24 @@ export async function sendMessage() {
         msgsToAdd.push(msg);
     }
 
-    // 更新会话标题
-    if (currentSession.messages.length === 0) {
-        const titleText = text
-            || (pendingFiles.length > 0 ? `[文件: ${pendingFiles.map(f => f.name).join(', ')}]` : '[图片消息]');
-        currentSession.title = truncate(titleText, 30);
-        currentSession.model = model;
-    }
+    // 更新会话标题 + 追加消息（通过 update 确保引用变化，触发浅比较）
+    const isFirstMsg = currentSession.messages.length === 0;
+    state.update(KEYS.CURRENT_SESSION, session => ({
+        ...session,
+        ...(isFirstMsg && {
+            title: truncate(
+                text || (pendingFiles.length > 0 ? `[文件: ${pendingFiles.map(f => f.name).join(', ')}]` : '[图片消息]'),
+                30
+            ),
+            model
+        }),
+        messages: [...session.messages, ...msgsToAdd],
+        updatedAt: Date.now()
+    }));
+
+    // update() 产生新引用，后续必须从 state 读取最新值
+    const freshSession = state.get(KEYS.CURRENT_SESSION);
 
-    msgsToAdd.forEach(m => currentSession.messages.push(m));
     enableAutoScroll();
     renderMessages();
 
@@ -391,7 +400,7 @@ export async function sendMessage() {
     let modelName = '';
 
     try {
-        const apiMessages = buildApiMessages(currentSession.messages);
+        const apiMessages = buildApiMessages(freshSession.messages);
 
         const chatParams = {
             model,
@@ -502,7 +511,11 @@ ${ragContext}
             ...(finalStats && { eval_count: finalStats.eval_count, total_duration: finalStats.total_duration }),
             ...(ragSources && { ragSources })
         };
-        currentSession.messages.push(assistantMsg);
+        state.update(KEYS.CURRENT_SESSION, session => ({
+            ...session,
+            messages: [...session.messages, assistantMsg],
+            updatedAt: Date.now()
+        }));
 
         if (finalStats) {
             updateLastAssistantMessage(assistantContent, thinkContent || null, finalStats, modelName || null);
@@ -549,7 +562,11 @@ ${ragContext}
                 ...(thinkContent && { think: thinkContent }),
                 stopped: true
             };
-            currentSession.messages.push(partialMsg);
+            state.update(KEYS.CURRENT_SESSION, session => ({
+                ...session,
+                messages: [...session.messages, partialMsg],
+                updatedAt: Date.now()
+            }));
 
             if (contentDiv) {
                 let html = '';
@@ -584,7 +601,11 @@ ${ragContext}
                 content: assistantContent + '\n\n`[已中断]`',
                 timestamp: Date.now(),
             };
-            currentSession.messages.push(partialMsg);
+            state.update(KEYS.CURRENT_SESSION, session => ({
+                ...session,
+                messages: [...session.messages, partialMsg],
+                updatedAt: Date.now()
+            }));
             contentDiv.innerHTML = safeMarkdown(assistantContent) + '<p><code>[已中断]</code></p>';
             await saveCurrentSession();
         } else {

js/components/model-bar.js

@@ -24,8 +24,7 @@ export function initModelBar() {
         const model = modelSelectEl.value;
         if (db()) await db().saveSetting('selectedModel', model);
         state.set('_defaultModel', model);
-        const session = state.get(KEYS.CURRENT_SESSION);
-        if (session) session.model = model;
+        state.update(KEYS.CURRENT_SESSION, session => session ? ({ ...session, model }) : session);
         if (model) {
             await checkModelCapability(model);
         } else {

js/state.js

@@ -1,34 +1,166 @@
 /**
  * State - 轻量级响应式状态管理
- * 使用发布-订阅模式，状态变更时通知所有订阅者
+ *
+ * 优化点：
+ * 1. 结构化浅比较：对象按 key 数量 + 逐 key 严格比较，数组按长度 + 逐元素
+ * 2. update()：函数式更新，自动比较
+ * 3. setIn()：路径式嵌套更新，沿途浅拷贝确保引用变化
+ * 4. batch()：批量更新，合并通知
  */
 
+// ── 结构化浅比较 ──
+function shallowEqual(a, b) {
+    if (a === b) return true;
+    if (a == null || b == null) return a === b;
+    if (typeof a !== 'object' || typeof b !== 'object') return false;
+
+    // 数组：长度 + 逐元素
+    if (Array.isArray(a) && Array.isArray(b)) {
+        if (a.length !== b.length) return false;
+        for (let i = 0; i < a.length; i++) {
+            if (a[i] !== b[i]) return false;
+        }
+        return true;
+    }
+
+    // 混合类型
+    if (Array.isArray(a) !== Array.isArray(b)) return false;
+
+    // 对象：key 数量 + 逐 key
+    const keysA = Object.keys(a);
+    const keysB = Object.keys(b);
+    if (keysA.length !== keysB.length) return false;
+    for (const key of keysA) {
+        if (!Object.prototype.hasOwnProperty.call(b, key) || a[key] !== b[key]) return false;
+    }
+    return true;
+}
+
 class AppState {
     constructor() {
         this._state = {};
-        this._listeners = new Map(); // key → Set<callback>
+        this._listeners = new Map();
+        this._batching = false;
+        this._batchQueue = null;
     }
 
     /**
-     * 设置状态值并通知订阅者
-     * @param {string} key - 状态键名
-     * @param {*} value - 状态值
+     * 设置状态值，使用结构化浅比较判断变更
      */
     set(key, value) {
         const old = this._state[key];
         this._state[key] = value;
-        if (old !== value && this._listeners.has(key)) {
-            for (const cb of this._listeners.get(key)) {
-                try { cb(value, old); } catch (e) { console.error(`[State] 监听器错误 (${key}):`, e); }
+
+        if (!shallowEqual(old, value)) {
+            if (this._batching) {
+                this._batchQueue.add(key);
+            } else {
+                this._notify(key, value, old);
+            }
+        }
+    }
+
+    /**
+     * 函数式更新：基于当前值计算新值，自动比较
+     *
+     * state.update('currentSession', session => ({
+     *     ...session,
+     *     messages: [...session.messages, newMsg],
+     *     updatedAt: Date.now()
+     * }));
+     */
+    update(key, updater) {
+        const old = this._state[key];
+        const value = updater(old);
+        this._state[key] = value;
+
+        if (!shallowEqual(old, value)) {
+            if (this._batching) {
+                this._batchQueue.add(key);
+            } else {
+                this._notify(key, value, old);
+            }
+        }
+    }
+
+    /**
+     * 路径式嵌套更新：按 path 更新嵌套属性，沿途浅拷贝确保引用变化
+     *
+     * state.setIn('currentSession', ['messages', 0, 'content'], '新内容');
+     */
+    setIn(key, path, value) {
+        if (!path || path.length === 0) {
+            this.set(key, value);
+            return;
+        }
+
+        const old = this._state[key];
+        if (old == null || typeof old !== 'object') {
+            console.warn(`[State] setIn 失败: ${key} 不是对象`);
+            return;
+        }
+
+        const newRoot = Array.isArray(old) ? [...old] : { ...old };
+        let current = newRoot;
+
+        for (let i = 0; i < path.length - 1; i++) {
+            const segment = path[i];
+            const next = current[segment];
+            if (next == null || typeof next !== 'object') {
+                const isIndex = typeof path[i + 1] === 'number';
+                current[segment] = isIndex ? [] : {};
+            } else {
+                current[segment] = Array.isArray(next) ? [...next] : { ...next };
+            }
+            current = current[segment];
+        }
+
+        current[path[path.length - 1]] = value;
+
+        this._state[key] = newRoot;
+        if (!shallowEqual(old, newRoot)) {
+            if (this._batching) {
+                this._batchQueue.add(key);
+            } else {
+                this._notify(key, newRoot, old);
+            }
+        }
+    }
+
+    /**
+     * 批量更新：合并多次 set 为一次通知
+     *
+     * state.batch(() => {
+     *     state.set('isStreaming', false);
+     *     state.update('currentSession', s => ({ ...s, updatedAt: Date.now() }));
+     * });
+     */
+    batch(fn) {
+        this._batching = true;
+        this._batchQueue = new Set();
+        try {
+            fn();
+        } finally {
+            const keys = this._batchQueue;
+            this._batching = false;
+            this._batchQueue = null;
+            for (const k of keys) {
+                this._notify(k, this._state[k], undefined);
+            }
+        }
+    }
+
+    _notify(key, value, old) {
+        if (!this._listeners.has(key)) return;
+        for (const cb of this._listeners.get(key)) {
+            try { cb(value, old); } catch (e) {
+                console.error(`[State] 监听器错误 (${key}):`, e);
             }
         }
     }
 
     /**
      * 获取状态值
-     * @param {string} key - 状态键名
-     * @param {*} [defaultValue] - 默认值
-     * @returns {*}
      */
     get(key, defaultValue = undefined) {
         return key in this._state ? this._state[key] : defaultValue;
@@ -36,8 +168,6 @@ class AppState {
 
     /**
      * 订阅状态变更
-     * @param {string} key - 状态键名
-     * @param {function} callback - 回调函数 (newValue, oldValue) => void
      * @returns {function} 取消订阅函数
      */
     on(key, callback) {
@@ -50,7 +180,6 @@ class AppState {
 
     /**
      * 批量设置初始状态
-     * @param {Object} initial - 初始状态对象
      */
     init(initial) {
         Object.assign(this._state, initial);
@@ -60,7 +189,6 @@ class AppState {
 // 单例
 export const state = new AppState();
 
-// ── 状态键名常量 ──
 export const KEYS = {
     DB: 'db',
     API: 'api',