optimize polling strategy

sessionManager.mjs

@@ -70,6 +70,10 @@ class SessionManager {
 
             // 记录请求次数
             session.youTotalRequests = 0;
+            // 权重
+            if (typeof session.weight !== 'number') {
+                session.weight = 1;
+            }
         }
     }
 
@@ -224,7 +228,7 @@ class SessionManager {
                     return browserInstance;
                 }
             }
-            throw new Error('当前负载已饱和，请稍后再试');
+            throw new Error('当前负载已饱和，请稍后再试(以达到最大并发)');
         });
     }
 
@@ -240,46 +244,80 @@ class SessionManager {
     async getAvailableSessions() {
         const allSessionsLocked = this.usernameList.every(username => this.sessions[username].locked);
         if (allSessionsLocked) {
-            throw new Error('所有会话处于饱和状态，请稍后再试');
+            throw new Error('所有会话处于饱和状态，请稍后再试(无可用账号)');
         }
 
-        // 轮询
-        const totalSessions = this.usernameList.length;
-        for (let i = 0; i < totalSessions; i++) {
-            const index = (this.currentIndex + i) % totalSessions;
-            const username = this.usernameList[index];
+        // 收集所有valid && !locked && (不在冷却期)
+        let candidates = [];
+        for (const username of this.usernameList) {
             const session = this.sessions[username];
-
             // 如果没被锁 并且 session.valid
             if (session.valid && !session.locked) {
                 if (this.provider.enableRequestLimit && this.isInCooldown(username)) {
                     // console.log(`账号 ${username} 处于 24 小时冷却中，跳过`);
                     continue;
                 }
+                candidates.push(username);
+            }
+        }
 
-                const result = await session.mutex.runExclusive(async () => {
-                    // 再次检查锁定状态
-                    if (session.locked) {
+        if (candidates.length === 0) {
+            throw new Error('没有可用的会话');
+        }
+
+        // 随机洗牌
+        shuffleArray(candidates);
+
+        // 加权抽签
+        let weightSum = 0;
+        for (const uname of candidates) {
+            weightSum += this.sessions[uname].weight;
+        }
+
+        // 生成随机
+        const randValue = Math.floor(Math.random() * weightSum) + 1;
+
+        // 遍历并扣减
+        let cumulative = 0;
+        let selectedUsername = null;
+        for (const uname of candidates) {
+            cumulative += this.sessions[uname].weight;
+            if (randValue <= cumulative) {
+                selectedUsername = uname;
+                break;
+            }
+        }
+
+        if (!selectedUsername) {
+            selectedUsername = candidates[0];
+        }
+
+        const selectedSession = this.sessions[selectedUsername];
+
+        // 再尝试锁定账号
+        const result = await selectedSession.mutex.runExclusive(async () => {
+            if (selectedSession.locked) {
                 return null;
             }
-                    // 检查模式状态
-                    if (session.modeStatus && session.modeStatus[session.currentMode]) {
-                        session.locked = true;
-                        session.requestCount++;
-                        this.currentIndex = (index + 1) % totalSessions;
 
-                        // 获取可用浏览器实例
+            // 判断是否可用
+            if (selectedSession.modeStatus && selectedSession.modeStatus[selectedSession.currentMode]) {
+                // 锁定
+                selectedSession.locked = true;
+                selectedSession.requestCount++;
+
+                // 获取可用浏览器
                 const browserInstance = await this.getAvailableBrowser();
 
-                        // 启动计时器
+                // 启动自动解锁计时器
                 if (SESSION_LOCK_TIMEOUT > 0) {
-                            this.startAutoUnlockTimer(username, browserInstance.id);
+                    this.startAutoUnlockTimer(selectedUsername, browserInstance.id);
                 }
 
                 return {
-                            selectedUsername: username,
+                    selectedUsername,
                     modeSwitched: false,
-                            browserInstance: browserInstance
+                    browserInstance
                 };
             } else if (
                 this.isCustomModeEnabled &&
@@ -287,40 +325,36 @@ class SessionManager {
                 this.provider &&
                 typeof this.provider.switchMode === 'function'
             ) {
-                        console.warn(`尝试为账号 ${username} 切换模式...`);
-                        this.provider.switchMode(session);
-                        session.rotationEnabled = false;
+                console.warn(`尝试为账号 ${selectedUsername} 切换模式...`);
+                this.provider.switchMode(selectedSession);
+                selectedSession.rotationEnabled = false;
 
-                        if (session.modeStatus && session.modeStatus[session.currentMode]) {
-                            session.locked = true;
-                            session.requestCount++;
-                            this.currentIndex = (index + 1) % totalSessions;
-
-                            // 获取可用浏览器实例
+                if (selectedSession.modeStatus && selectedSession.modeStatus[selectedSession.currentMode]) {
+                    selectedSession.locked = true;
+                    selectedSession.requestCount++;
                     const browserInstance = await this.getAvailableBrowser();
 
                     if (SESSION_LOCK_TIMEOUT > 0) {
-                                this.startAutoUnlockTimer(username, browserInstance.id);
+                        this.startAutoUnlockTimer(selectedUsername, browserInstance.id);
                     }
 
                     return {
-                                selectedUsername: username,
+                        selectedUsername,
                         modeSwitched: true,
-                                browserInstance: browserInstance
+                        browserInstance
                     };
                 }
             }
+
             return null;
         });
 
         if (result) {
-                    // 成功锁定会话，返回
             return result;
+        } else {
+            throw new Error('会话刚被占用或模式不可用!');
         }
     }
-        }
-        throw new Error('没有可用的会话');
-    }
 
     startAutoUnlockTimer(username, browserId) {
         // 清除可能残留计时器
@@ -376,4 +410,14 @@ class SessionManager {
     }
 }
 
+/**
+ * Fisher–Yates 洗牌
+ */
+function shuffleArray(array) {
+    for (let i = array.length - 1; i > 0; i--) {
+        const j = Math.floor(Math.random() * (i + 1));
+        [array[i], array[j]] = [array[j], array[i]];
+    }
+}
+
 export default SessionManager;