Upload 47 files

components/Sidebar.tsx

@@ -2,6 +2,7 @@
 import React from 'react';
 import { LayoutDashboard, Users, BookOpen, GraduationCap, Settings, LogOut, FileText, School, UserCog, Palette, X, Building, Gamepad2, CalendarCheck, UserCircle, MessageSquare, Bot } from 'lucide-react';
 import { UserRole } from '../types';
+import { api } from '../services/api';
 
 interface SidebarProps {
   currentView: string;
@@ -13,11 +14,16 @@ interface SidebarProps {
 }
 
 export const Sidebar: React.FC<SidebarProps> = ({ currentView, onChangeView, userRole, onLogout, isOpen, onClose }) => {
+  // Get full user object to check aiAccess flag
+  const currentUser = api.auth.getCurrentUser();
+  const hasAIAccess = userRole === UserRole.ADMIN || (userRole === UserRole.TEACHER && currentUser?.aiAccess);
+
   // Define menu items with explicit roles
   // PRINCIPAL has access to almost everything ADMIN has, except 'schools' management
   const menuItems = [
     { id: 'dashboard', label: '工作台', icon: LayoutDashboard, roles: [UserRole.ADMIN, UserRole.PRINCIPAL, UserRole.TEACHER, UserRole.STUDENT] },
-    { id: 'ai-assistant', label: 'AI 智能助教', icon: Bot, roles: [UserRole.TEACHER, UserRole.STUDENT] }, // NEW
+    // AI Assistant: Only if hasAIAccess is true (Admin, or Authorized Teacher)
+    { id: 'ai-assistant', label: 'AI 智能助教', icon: Bot, roles: hasAIAccess ? [UserRole.ADMIN, UserRole.TEACHER] : [] }, 
     { id: 'attendance', label: '考勤管理', icon: CalendarCheck, roles: [UserRole.TEACHER, UserRole.PRINCIPAL] }, 
     { id: 'games', label: '互动教学', icon: Gamepad2, roles: [UserRole.TEACHER, UserRole.STUDENT] }, // Removed PRINCIPAL
     { id: 'wishes', label: '心愿与反馈', icon: MessageSquare, roles: [UserRole.ADMIN, UserRole.PRINCIPAL, UserRole.TEACHER, UserRole.STUDENT] }, // NEW
@@ -95,4 +101,4 @@ export const Sidebar: React.FC<SidebarProps> = ({ currentView, onChangeView, use
       </div>
     </>
   );
-};
+};

index.html

@@ -31,7 +31,8 @@
     "vite": "https://aistudiocdn.com/vite@^7.2.6",
     "@vitejs/plugin-react": "https://aistudiocdn.com/@vitejs/plugin-react@^5.1.1",
     "react-dom": "https://aistudiocdn.com/react-dom@^19.2.0",
-    "xlsx": "https://aistudiocdn.com/xlsx@^0.18.5"
+    "xlsx": "https://aistudiocdn.com/xlsx@^0.18.5",
+    "@google/genai": "https://esm.sh/@google/genai@^1.33.0"
   }
 }
 </script>

models.js

@@ -26,6 +26,8 @@ const UserSchema = new mongoose.Schema({
     gender: String, 
     seatNo: String, 
     idCard: String,
+    // NEW: Control AI feature access for teachers
+    aiAccess: { type: Boolean, default: false },
     classApplication: { 
         type: { type: String }, 
         targetClass: String, 
@@ -34,6 +36,7 @@ const UserSchema = new mongoose.Schema({
 });
 const User = mongoose.model('User', UserSchema);
 
+// ... (Rest of the file remains unchanged)
 const StudentSchema = new mongoose.Schema({ 
     schoolId: String, 
     studentNo: String, 
@@ -225,4 +228,4 @@ module.exports = {
     ConfigModel, NotificationModel, GameSessionModel, StudentRewardModel, LuckyDrawConfigModel, GameMonsterConfigModel, GameZenConfigModel,
     AchievementConfigModel, TeacherExchangeConfigModel, StudentAchievementModel, AttendanceModel, LeaveRequestModel, SchoolCalendarModel,
     WishModel, FeedbackModel
-};
+};

pages/AIAssistant.tsx

@@ -1,9 +1,8 @@
 
 import React, { useState, useRef, useEffect } from 'react';
 import { api } from '../services/api';
-import { AIChatMessage, OralAssessment } from '../types';
-import { Bot, Mic, Square, Play, Volume2, Send, CheckCircle, Brain, Sparkles, Loader2, StopCircle } from 'lucide-react';
-import { Emoji } from '../components/Emoji';
+import { AIChatMessage } from '../types';
+import { Bot, Mic, Square, Play, Volume2, Send, CheckCircle, Brain, Sparkles, Loader2, StopCircle, Trash2, Image as ImageIcon, X } from 'lucide-react';
 
 // Utility to handle Base64 conversion
 const blobToBase64 = (blob: Blob): Promise<string> => {
@@ -18,35 +17,16 @@ const blobToBase64 = (blob: Blob): Promise<string> => {
   });
 };
 
-// Utility to decode and play PCM audio (standard Web Audio API)
-const playPCMAudio = async (base64Audio: string, audioContext: AudioContext) => {
-    try {
-        const binaryString = window.atob(base64Audio);
-        const len = binaryString.length;
-        const bytes = new Uint8Array(len);
-        for (let i = 0; i < len; i++) {
-            bytes[i] = binaryString.charCodeAt(i);
-        }
-        
-        // Gemini TTS raw output usually needs specific handling. 
-        // If it's pure PCM, we need to wrap it. However, the Gemini API usually returns standard formats if requested or PCM.
-        // Assuming raw PCM 24kHz mono based on documentation typically seen.
-        const int16Data = new Int16Array(bytes.buffer);
-        const float32Data = new Float32Array(int16Data.length);
-        for (let i = 0; i < int16Data.length; i++) {
-            float32Data[i] = int16Data[i] / 32768.0;
-        }
-
-        const buffer = audioContext.createBuffer(1, float32Data.length, 24000); // Gemini Flash TTS default
-        buffer.getChannelData(0).set(float32Data);
-
-        const source = audioContext.createBufferSource();
-        source.buffer = buffer;
-        source.connect(audioContext.destination);
-        source.start();
-    } catch (e) {
-        console.error("Audio playback error:", e);
-    }
+const fileToBase64 = (file: File): Promise<string> => {
+    return new Promise((resolve, reject) => {
+        const reader = new FileReader();
+        reader.readAsDataURL(file);
+        reader.onload = () => {
+            const str = reader.result as string;
+            resolve(str.split(',')[1]);
+        };
+        reader.onerror = error => reject(error);
+    });
 };
 
 export const AIAssistant: React.FC = () => {
@@ -62,11 +42,14 @@ export const AIAssistant: React.FC = () => {
     // Assessment State
     const [assessmentTopic, setAssessmentTopic] = useState('请描述你最喜欢的一个季节及其原因。');
     const [assessmentResult, setAssessmentResult] = useState<any>(null);
+    const [assessmentMode, setAssessmentMode] = useState<'audio' | 'image'>('audio');
+    const [selectedImage, setSelectedImage] = useState<File | null>(null);
 
     // Audio Refs
     const mediaRecorderRef = useRef<MediaRecorder | null>(null);
     const audioChunksRef = useRef<Blob[]>([]);
     const audioContextRef = useRef<AudioContext | null>(null);
+    const currentSourceRef = useRef<AudioBufferSourceNode | null>(null);
 
     useEffect(() => {
         // Init Audio Context
@@ -79,13 +62,65 @@ export const AIAssistant: React.FC = () => {
             setMessages([{
                 id: 'welcome',
                 role: 'model',
-                text: '你好！我是你的 AI 智能助教。你可以问我任何学习上的问题，或者切换到“口语测评”模式来练习口语。',
+                text: '你好！我是你的 AI 智能助教。你可以问我任何学习上的问题，或者切换到“口语/背诵测评”模式。',
                 timestamp: Date.now()
             }]);
         }
+
+        return () => {
+            stopPlayback(); // Cleanup audio on unmount
+        };
     }, []);
 
+    const stopPlayback = () => {
+        if (currentSourceRef.current) {
+            try {
+                currentSourceRef.current.stop();
+            } catch (e) { /* ignore already stopped */ }
+            currentSourceRef.current = null;
+        }
+    };
+
+    const playPCMAudio = async (base64Audio: string) => {
+        if (!audioContextRef.current) return;
+        
+        stopPlayback(); // Stop any existing audio
+
+        try {
+            const binaryString = window.atob(base64Audio);
+            const len = binaryString.length;
+            const bytes = new Uint8Array(len);
+            for (let i = 0; i < len; i++) {
+                bytes[i] = binaryString.charCodeAt(i);
+            }
+            
+            // Assuming 24kHz mono PCM (Gemini Standard)
+            const int16Data = new Int16Array(bytes.buffer);
+            const float32Data = new Float32Array(int16Data.length);
+            for (let i = 0; i < int16Data.length; i++) {
+                float32Data[i] = int16Data[i] / 32768.0;
+            }
+
+            const buffer = audioContextRef.current.createBuffer(1, float32Data.length, 24000);
+            buffer.getChannelData(0).set(float32Data);
+
+            const source = audioContextRef.current.createBufferSource();
+            source.buffer = buffer;
+            source.connect(audioContextRef.current.destination);
+            source.start();
+            currentSourceRef.current = source;
+            
+            source.onended = () => {
+                currentSourceRef.current = null;
+            };
+
+        } catch (e) {
+            console.error("Audio playback error:", e);
+        }
+    };
+
     const startRecording = async () => {
+        stopPlayback();
         try {
             const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
             const mediaRecorder = new MediaRecorder(stream);
@@ -118,7 +153,7 @@ export const AIAssistant: React.FC = () => {
                 if (activeTab === 'chat') {
                     handleChatSubmit(undefined, base64Audio);
                 } else {
-                    handleAssessmentSubmit(base64Audio);
+                    handleAssessmentSubmit({ audio: base64Audio });
                 }
                 
                 // Stop all tracks
@@ -129,6 +164,13 @@ export const AIAssistant: React.FC = () => {
 
     const handleChatSubmit = async (text?: string, audioBase64?: string) => {
         if (!text && !audioBase64) return;
+        stopPlayback();
+
+        // 1. Prepare history for context (exclude welcome message usually, or keep it depending on desired persona persistence)
+        // Convert to simplified format for API: { role: 'user' | 'model', text: string }
+        const historyPayload = messages
+            .filter(m => m.id !== 'welcome') // Optional: Exclude greeting to save tokens
+            .map(m => ({ role: m.role, text: m.text }));
 
         // Optimistic UI Update
         const newUserMsg: AIChatMessage = {
@@ -143,7 +185,12 @@ export const AIAssistant: React.FC = () => {
         setIsProcessing(true);
 
         try {
-            const response = await api.ai.chat({ text, audio: audioBase64 });
+            const response = await api.ai.chat({ 
+                text, 
+                audio: audioBase64,
+                // @ts-ignore
+                history: historyPayload 
+            });
             
             const newAiMsg: AIChatMessage = {
                 id: (Date.now() + 1).toString(),
@@ -154,50 +201,94 @@ export const AIAssistant: React.FC = () => {
             };
             setMessages(prev => [...prev, newAiMsg]);
 
-            // Auto play audio if response contains it
-            if (response.audio && audioContextRef.current) {
-                playPCMAudio(response.audio, audioContextRef.current);
+            if (response.audio) {
+                playPCMAudio(response.audio);
             }
 
         } catch (error) {
             console.error("Chat error:", error);
-            setMessages(prev => [...prev, { id: Date.now().toString(), role: 'model', text: '抱歉，我遇到了一点问题，请稍后再试。', timestamp: Date.now() }]);
+            setMessages(prev => [...prev, { id: Date.now().toString(), role: 'model', text: '抱歉，遇到错误，请重试。', timestamp: Date.now() }]);
         } finally {
             setIsProcessing(false);
         }
     };
 
-    const handleAssessmentSubmit = async (audioBase64: string) => {
+    const handleAssessmentSubmit = async ({ audio, image }: { audio?: string, image?: string }) => {
+        stopPlayback();
         setIsProcessing(true);
         setAssessmentResult(null);
+        
         try {
             const result = await api.ai.evaluate({
                 question: assessmentTopic,
-                audio: audioBase64
+                audio,
+                image
             });
             setAssessmentResult(result);
+            if (result.audio) {
+                // Auto play feedback audio
+                playPCMAudio(result.audio);
+            }
         } catch (error) {
             console.error("Eval error:", error);
             alert("评分失败，请重试");
         } finally {
             setIsProcessing(false);
+            setSelectedImage(null); // Clear image after submit
+        }
+    };
+
+    const handleImageUpload = async (e: React.ChangeEvent<HTMLInputElement>) => {
+        if (e.target.files && e.target.files[0]) {
+            const file = e.target.files[0];
+            setSelectedImage(file);
+            
+            // Auto submit or wait? Let's wait for user confirmation if needed, but for simplicity auto-submit:
+            // Actually better to show preview then submit
         }
     };
 
-    const playMessageAudio = (b64: string) => {
-        if (audioContextRef.current) playPCMAudio(b64, audioContextRef.current);
+    const confirmImageSubmission = async () => {
+        if (!selectedImage) return;
+        const b64 = await fileToBase64(selectedImage);
+        handleAssessmentSubmit({ image: b64 });
+    };
+
+    const clearHistory = () => {
+        setMessages([{
+            id: 'welcome',
+            role: 'model',
+            text: '对话记录已清除��我是你的 AI 智能助教。',
+            timestamp: Date.now()
+        }]);
     };
 
     return (
-        <div className="h-full flex flex-col bg-slate-50 overflow-hidden">
+        <div className="h-full flex flex-col bg-slate-50 overflow-hidden relative">
+            {/* Audio Stop Overlay Button (Visible when audio playing context exists? simplified: always visible top right if needed) */}
+            <button 
+                onClick={stopPlayback} 
+                className="absolute top-20 right-4 z-50 bg-white/80 backdrop-blur p-2 rounded-full shadow-md text-red-500 hover:bg-white border border-gray-200"
+                title="停止播放"
+            >
+                <StopCircle size={20}/>
+            </button>
+
             {/* Header Tabs */}
-            <div className="bg-white border-b border-gray-200 px-6 pt-4 flex gap-6 shrink-0 shadow-sm z-10">
-                <button onClick={() => setActiveTab('chat')} className={`pb-3 text-sm font-bold border-b-2 transition-colors flex items-center gap-2 ${activeTab === 'chat' ? 'border-blue-500 text-blue-600' : 'border-transparent text-gray-500 hover:text-gray-700'}`}>
-                    <Bot size={18} className={activeTab === 'chat' ? 'text-blue-500' : ''}/> AI 助教 (问答)
-                </button>
-                <button onClick={() => setActiveTab('assessment')} className={`pb-3 text-sm font-bold border-b-2 transition-colors flex items-center gap-2 ${activeTab === 'assessment' ? 'border-purple-500 text-purple-600' : 'border-transparent text-gray-500 hover:text-gray-700'}`}>
-                    <Mic size={18} className={activeTab === 'assessment' ? 'text-purple-500' : ''}/> 口语/背诵测评
-                </button>
+            <div className="bg-white border-b border-gray-200 px-6 pt-4 flex justify-between shrink-0 shadow-sm z-10">
+                <div className="flex gap-6">
+                    <button onClick={() => setActiveTab('chat')} className={`pb-3 text-sm font-bold border-b-2 transition-colors flex items-center gap-2 ${activeTab === 'chat' ? 'border-blue-500 text-blue-600' : 'border-transparent text-gray-500 hover:text-gray-700'}`}>
+                        <Bot size={18} className={activeTab === 'chat' ? 'text-blue-500' : ''}/> AI 助教 (问答)
+                    </button>
+                    <button onClick={() => setActiveTab('assessment')} className={`pb-3 text-sm font-bold border-b-2 transition-colors flex items-center gap-2 ${activeTab === 'assessment' ? 'border-purple-500 text-purple-600' : 'border-transparent text-gray-500 hover:text-gray-700'}`}>
+                        <Mic size={18} className={activeTab === 'assessment' ? 'text-purple-500' : ''}/> 口语/背诵测评
+                    </button>
+                </div>
+                {activeTab === 'chat' && (
+                    <button onClick={clearHistory} className="mb-2 text-xs text-gray-400 hover:text-red-500 flex items-center gap-1">
+                        <Trash2 size={14}/> 清除记录
+                    </button>
+                )}
             </div>
 
             {/* TAB: CHAT */}
@@ -212,7 +303,7 @@ export const AIAssistant: React.FC = () => {
                                 <div className={`max-w-[80%] p-3 rounded-2xl text-sm ${msg.role === 'user' ? 'bg-blue-600 text-white rounded-tr-none' : 'bg-white border border-gray-200 text-gray-800 rounded-tl-none shadow-sm'}`}>
                                     {msg.text}
                                     {msg.audio && (
-                                        <button onClick={() => playMessageAudio(msg.audio!)} className="mt-2 flex items-center gap-2 text-xs bg-blue-50 text-blue-600 px-3 py-1.5 rounded-full hover:bg-blue-100 border border-blue-100 transition-colors w-fit">
+                                        <button onClick={() => playPCMAudio(msg.audio!)} className="mt-2 flex items-center gap-2 text-xs bg-blue-50 text-blue-600 px-3 py-1.5 rounded-full hover:bg-blue-100 border border-blue-100 transition-colors w-fit">
                                             <Volume2 size={14}/> 播放语音
                                         </button>
                                     )}
@@ -224,7 +315,7 @@ export const AIAssistant: React.FC = () => {
                                 <div className="w-10 h-10 rounded-full bg-blue-100 text-blue-600 flex items-center justify-center">
                                     <Loader2 className="animate-spin" size={20}/>
                                 </div>
-                                <div className="text-sm text-gray-400 self-center">AI 正在思考中...</div>
+                                <div className="text-sm text-gray-400 self-center">AI 正在思考上下文...</div>
                             </div>
                         )}
                     </div>
@@ -270,7 +361,7 @@ export const AIAssistant: React.FC = () => {
                                 </button>
                             )}
                         </div>
-                        <p className="text-center text-[10px] text-gray-400 mt-2">Gemini Flash-Lite 模型提供支持</p>
+                        <p className="text-center text-[10px] text-gray-400 mt-2">支持多轮对话 | 实时语音合成</p>
                     </div>
                 </div>
             )}
@@ -281,8 +372,12 @@ export const AIAssistant: React.FC = () => {
                     <div className="max-w-3xl mx-auto space-y-6">
                         {/* Topic Card */}
                         <div className="bg-white p-6 rounded-2xl border border-purple-100 shadow-sm">
-                            <h3 className="text-lg font-bold text-gray-800 mb-2 flex items-center">
-                                <Brain className="mr-2 text-purple-600"/> 今日测评题目
+                            <h3 className="text-lg font-bold text-gray-800 mb-2 flex items-center justify-between">
+                                <span className="flex items-center"><Brain className="mr-2 text-purple-600"/> 今日测评题目</span>
+                                <div className="flex bg-gray-100 p-1 rounded-lg text-xs font-medium">
+                                    <button onClick={()=>setAssessmentMode('audio')} className={`px-3 py-1 rounded-md transition-all ${assessmentMode==='audio'?'bg-white shadow text-purple-600':'text-gray-500'}`}>语音回答</button>
+                                    <button onClick={()=>setAssessmentMode('image')} className={`px-3 py-1 rounded-md transition-all ${assessmentMode==='image'?'bg-white shadow text-purple-600':'text-gray-500'}`}>拍照上传</button>
+                                </div>
                             </h3>
                             <textarea 
                                 className="w-full bg-purple-50/50 border border-purple-100 rounded-xl p-4 text-gray-700 font-medium text-lg resize-none focus:ring-2 focus:ring-purple-200 outline-none"
@@ -290,18 +385,43 @@ export const AIAssistant: React.FC = () => {
                                 onChange={e => setAssessmentTopic(e.target.value)}
                                 rows={3}
                             />
-                            <div className="mt-4 flex justify-center">
-                                <button 
-                                    onMouseDown={startRecording}
-                                    onMouseUp={stopRecording}
-                                    onTouchStart={startRecording}
-                                    onTouchEnd={stopRecording}
-                                    disabled={isProcessing}
-                                    className={`px-8 py-4 rounded-full font-bold text-white flex items-center gap-3 shadow-lg transition-all ${isRecording ? 'bg-red-500 scale-105' : 'bg-gradient-to-r from-purple-600 to-indigo-600 hover:shadow-purple-200 hover:scale-105'}`}
-                                >
-                                    {isProcessing ? <Loader2 className="animate-spin"/> : (isRecording ? <StopCircle/> : <Mic/>)}
-                                    {isProcessing ? 'AI 正在评分...' : (isRecording ? '松开结束录音' : '按住开始回答')}
-                                </button>
+                            
+                            <div className="mt-6 flex justify-center">
+                                {assessmentMode === 'audio' ? (
+                                    <button 
+                                        onMouseDown={startRecording}
+                                        onMouseUp={stopRecording}
+                                        onTouchStart={startRecording}
+                                        onTouchEnd={stopRecording}
+                                        disabled={isProcessing}
+                                        className={`px-8 py-4 rounded-full font-bold text-white flex items-center gap-3 shadow-lg transition-all ${isRecording ? 'bg-red-500 scale-105' : 'bg-gradient-to-r from-purple-600 to-indigo-600 hover:shadow-purple-200 hover:scale-105'}`}
+                                    >
+                                        {isProcessing ? <Loader2 className="animate-spin"/> : (isRecording ? <StopCircle/> : <Mic/>)}
+                                        {isProcessing ? 'AI 正在评分...' : (isRecording ? '松开结束录音' : '按住开始回答')}
+                                    </button>
+                                ) : (
+                                    <div className="w-full">
+                                        {!selectedImage ? (
+                                            <div className="border-2 border-dashed border-purple-200 rounded-xl p-8 text-center hover:bg-purple-50 transition-colors cursor-pointer relative">
+                                                <input type="file" accept="image/*" className="absolute inset-0 opacity-0 cursor-pointer" onChange={handleImageUpload}/>
+                                                <ImageIcon className="mx-auto text-purple-300 mb-2" size={40}/>
+                                                <p className="text-purple-600 font-bold">点击上传作业图片</p>
+                                                <p className="text-xs text-gray-400">支持手写文字识别与批改</p>
+                                            </div>
+                                        ) : (
+                                            <div className="flex flex-col items-center gap-4">
+                                                <div className="relative">
+                                                    <img src={URL.createObjectURL(selectedImage)} className="h-40 rounded-lg shadow-sm border"/>
+                                                    <button onClick={()=>setSelectedImage(null)} className="absolute -top-2 -right-2 bg-red-500 text-white rounded-full p-1"><X size={14}/></button>
+                                                </div>
+                                                <button onClick={confirmImageSubmission} disabled={isProcessing} className="px-8 py-2 bg-purple-600 text-white rounded-lg font-bold hover:bg-purple-700 flex items-center gap-2">
+                                                    {isProcessing ? <Loader2 className="animate-spin" size={16}/> : <CheckCircle size={16}/>}
+                                                    开始批改
+                                                </button>
+                                            </div>
+                                        )}
+                                    </div>
+                                )}
                             </div>
                         </div>
 
@@ -310,20 +430,26 @@ export const AIAssistant: React.FC = () => {
                             <div className="bg-white p-6 rounded-2xl border border-gray-200 shadow-lg animate-in slide-in-from-bottom-4">
                                 <div className="flex items-center justify-between border-b border-gray-100 pb-4 mb-4">
                                     <h3 className="font-bold text-xl text-gray-800">测评报告</h3>
-                                    <div className={`text-3xl font-black ${assessmentResult.score >= 80 ? 'text-green-500' : assessmentResult.score >= 60 ? 'text-yellow-500' : 'text-red-500'}`}>
-                                        {assessmentResult.score}<span className="text-sm text-gray-400 ml-1">分</span>
+                                    <div className="flex items-center gap-4">
+                                        {assessmentResult.audio && (
+                                            <button onClick={() => playPCMAudio(assessmentResult.audio)} className="flex items-center gap-1 text-sm bg-purple-100 text-purple-700 px-3 py-1 rounded-full hover:bg-purple-200">
+                                                <Volume2 size={16}/> 听点评
+                                            </button>
+                                        )}
+                                        <div className={`text-3xl font-black ${assessmentResult.score >= 80 ? 'text-green-500' : assessmentResult.score >= 60 ? 'text-yellow-500' : 'text-red-500'}`}>
+                                            {assessmentResult.score}<span className="text-sm text-gray-400 ml-1">分</span>
+                                        </div>
                                     </div>
                                 </div>
                                 
                                 <div className="space-y-4">
                                     <div className="bg-gray-50 p-4 rounded-xl">
-                                        <p className="text-xs font-bold text-gray-500 uppercase mb-1">AI 听到的内容 (识别文本)</p>
-                                        <p className="text-gray-700 leading-relaxed">{assessmentResult.transcription}</p>
+                                        <p className="text-xs font-bold text-gray-500 uppercase mb-1">AI 识别内容</p>
+                                        <p className="text-gray-700 leading-relaxed text-sm">{assessmentResult.transcription}</p>
                                     </div>
                                     <div>
                                         <p className="text-xs font-bold text-gray-500 uppercase mb-2">AI 点评建议</p>
-                                        <div className="p-4 bg-purple-50 text-purple-900 rounded-xl border border-purple-100 text-sm leading-relaxed">
-                                            <Emoji symbol="👨‍🏫" className="mr-2"/>
+                                        <div className="p-4 bg-purple-50 text-purple-900 rounded-xl border border-purple-100 text-sm leading-relaxed whitespace-pre-wrap">
                                             {assessmentResult.feedback}
                                         </div>
                                     </div>

pages/UserList.tsx

@@ -2,7 +2,7 @@
 import React, { useState, useEffect } from 'react';
 import { User, UserRole, UserStatus, School, ClassInfo } from '../types';
 import { api } from '../services/api';
-import { Loader2, Check, X, Trash2, Edit, Briefcase, GraduationCap, AlertCircle } from 'lucide-react';
+import { Loader2, Check, X, Trash2, Edit, Briefcase, GraduationCap, AlertCircle, Bot } from 'lucide-react';
 
 export const UserList: React.FC = () => {
   const [users, setUsers] = useState<User[]>([]);
@@ -22,13 +22,9 @@ export const UserList: React.FC = () => {
   const loadData = async () => {
     setLoading(true);
     try {
-      // Teachers need to see pending students for their class.
-      // API request:
-      // - Admin: global=true (gets all) or filtered by header
-      // - Principal: Standard request (backend uses header to filter by school and exclude admin)
       const [u, s, c] = await Promise.all([
          api.users.getAll({ global: isAdmin }), 
-         api.schools.getAll(), // Will return empty/public for non-admin but that's fine
+         api.schools.getAll(), 
          api.classes.getAll()
       ]);
       setUsers(u);
@@ -69,6 +65,14 @@ export const UserList: React.FC = () => {
     loadData();
   };
 
+  const handleAIToggle = async (user: User) => {
+      const newVal = !user.aiAccess;
+      if (confirm(`确认${newVal ? '开通' : '关闭'} ${user.trueName || user.username} 的 AI 助教权限？`)) {
+          await api.users.update(user._id || String(user.id), { aiAccess: newVal });
+          loadData();
+      }
+  };
+
   const submitClassApply = async () => {
       if (!applyTarget) return;
       try {
@@ -98,26 +102,20 @@ export const UserList: React.FC = () => {
 
   const getSchoolName = (id?: string) => schools.find(s => s._id === id)?.name || '未分配';
 
-  // Client-side Filtering Logic (Double security besides backend)
+  // Client-side Filtering Logic
   const filteredUsers = users.filter(user => {
      if (isAdmin) return true;
      
      if (isPrincipal) {
-         // Principal cannot see Admins or users from other schools
          if (user.role === UserRole.ADMIN) return false;
-         // Note: user.schoolId might be undefined for some legacy data, handle carefully
          if (user.schoolId !== currentUser.schoolId) return false;
          return true;
      }
 
      if (isTeacher) {
-        // Teacher sees ONLY Students
         if (user.role !== UserRole.STUDENT) return false;
-        
-        // Must match teacher's homeroom
         const teacherClass = (currentUser.homeroomClass || '').trim();
         const studentClass = (user.homeroomClass || '').trim();
-        
         if (teacherClass && studentClass === teacherClass) {
             return true;
         }
@@ -126,7 +124,7 @@ export const UserList: React.FC = () => {
      return false;
   });
 
-  if (loading) return <div className="flex justify-center py-10"><Loader2 className="animate-spin text-blue-600" /></div>;
+  if (loading) return <div className="flex justify-center py-10"><Loader2 className="animate-spin text-blue-600"/></div>;
 
   return (
     <div className="bg-white rounded-xl shadow-sm border border-gray-100 p-6">
@@ -171,13 +169,13 @@ export const UserList: React.FC = () => {
               <th className="px-4 py-3">所属学校</th>
               <th className="px-4 py-3">角色/班级</th>
               <th className="px-4 py-3">账号状态</th>
+              {(isAdmin || isPrincipal) && <th className="px-4 py-3 text-center">AI 权限</th>}
               <th className="px-4 py-3 text-right">操作</th>
             </tr>
           </thead>
           <tbody className="divide-y divide-gray-100">
             {filteredUsers.map(user => {
               const isSelf = !!(currentUser && (user._id === currentUser._id || user.username === currentUser.username));
-              
               const hasApp = user.classApplication && user.classApplication.status === 'PENDING';
 
               return (
@@ -252,6 +250,22 @@ export const UserList: React.FC = () => {
                    {user.status === 'banned' && <span className="bg-red-100 text-red-700 px-2 py-1 rounded-full text-xs">已停用</span>}
                    {hasApp && <span className="block mt-1 text-[10px] text-purple-500 font-bold bg-purple-50 px-1 rounded w-fit">申请变动中 (见班级管理)</span>}
                 </td>
+                
+                {/* AI Access Toggle */}
+                {(isAdmin || isPrincipal) && (
+                    <td className="px-4 py-3 text-center">
+                        {user.role === UserRole.TEACHER ? (
+                            <button 
+                                onClick={() => handleAIToggle(user)}
+                                className={`p-1.5 rounded-full transition-colors ${user.aiAccess ? 'bg-blue-100 text-blue-600' : 'bg-gray-100 text-gray-400 hover:bg-gray-200'}`}
+                                title={user.aiAccess ? "已开启 AI 助教" : "未开启 AI 助教"}
+                            >
+                                <Bot size={16} />
+                            </button>
+                        ) : <span className="text-gray-300">-</span>}
+                    </td>
+                )}
+
                 <td className="px-4 py-3 text-right space-x-2">
                    {user.status === UserStatus.PENDING && (
                      <button onClick={() => handleApprove(user)} className="text-green-600 hover:bg-green-50 p-1 rounded border border-green-200" title="通过注册审核">
@@ -294,4 +308,4 @@ export const UserList: React.FC = () => {
       )}
     </div>
   );
-};
+};

server.js

@@ -103,35 +103,109 @@ const generateStudentNo = async () => {
     return `${year}${random}`;
 };
 
+// --- Helper: Retry Logic for AI Calls (Fix 503 Errors) ---
+const wait = (ms) => new Promise(resolve => setTimeout(resolve, ms));
+
+async function callAIWithRetry(aiModel, params, retries = 3) {
+    for (let i = 0; i < retries; i++) {
+        try {
+            return await aiModel.generateContent(params);
+        } catch (e) {
+            // Check for 503 Service Unavailable or "overloaded" message
+            const isOverloaded = e.message?.includes('503') || 
+                                 e.status === 503 || 
+                                 e.message?.includes('overloaded');
+            
+            if (isOverloaded) {
+                if (i < retries - 1) {
+                    const delay = 1000 * Math.pow(2, i); // Exponential backoff: 1s, 2s, 4s...
+                    console.warn(`⚠️ AI Model Overloaded. Retrying in ${delay}ms... (Attempt ${i + 1}/${retries})`);
+                    await wait(delay);
+                    continue;
+                } else {
+                    console.error("❌ AI Model Overloaded: Max retries reached.");
+                }
+            }
+            throw e; // Re-throw other errors or if retries exhausted
+        }
+    }
+}
+
+// --- Middleware: Check AI Access ---
+const checkAIAccess = async (req, res, next) => {
+    const username = req.headers['x-user-username'];
+    if (!username) return res.status(401).json({ error: 'Unauthorized' });
+    
+    // Admins always have access
+    if (req.headers['x-user-role'] === 'ADMIN') return next();
+
+    const user = await User.findOne({ username });
+    if (!user) return res.status(404).json({ error: 'User not found' });
+    
+    // Students NO ACCESS
+    if (user.role === 'STUDENT') return res.status(403).json({ error: 'Students not allowed' });
+    
+    // Teachers need enabled flag
+    if (!user.aiAccess) return res.status(403).json({ error: 'AI Access not enabled for this user' });
+    
+    next();
+};
+
 // --- NEW AI ROUTES ---
 
-// Scenario 1: AI Chat (Audio In -> AI Think -> Text + Audio Out)
-app.post('/api/ai/chat', async (req, res) => {
-    const { text, audio } = req.body; // audio is base64 string
+// Scenario 1: AI Chat (Audio/Text In -> AI Think -> Text + Audio Out)
+// Now Supports History for Context
+app.post('/api/ai/chat', checkAIAccess, async (req, res) => {
+    const { text, audio, history } = req.body; 
     
     try {
-        // Dynamically import AI
         const { ai, Modality } = await getGenAI();
 
-        const parts = [];
+        // 1. Build Content parts for Current Turn
+        const currentParts = [];
         if (audio) {
-            parts.push({
+            currentParts.push({
                 inlineData: {
-                    mimeType: 'audio/wav', // Assuming browser sends WAV or compatible
+                    mimeType: 'audio/wav',
                     data: audio
                 }
             });
         }
         if (text) {
-            parts.push({ text: text });
+            currentParts.push({ text: text });
         }
+        if (currentParts.length === 0) return res.status(400).json({ error: 'No input provided' });
+
+        // 2. Build Full Context (History + Current)
+        // Gemini API `contents` is an array of messages
+        const fullContents = [];
         
-        if (parts.length === 0) return res.status(400).json({ error: 'No input provided' });
+        // Add previous history if exists
+        if (history && Array.isArray(history)) {
+            history.forEach(msg => {
+                // Ensure valid role mapping
+                const role = msg.role === 'user' ? 'user' : 'model';
+                // Only text history is robustly supported in stateless mode for now to save bandwidth/complexity
+                // (Passing back audio bytes in history is heavy)
+                if (msg.text) {
+                    fullContents.push({
+                        role: role,
+                        parts: [{ text: msg.text }]
+                    });
+                }
+            });
+        }
+
+        // Add current message
+        fullContents.push({
+            role: 'user',
+            parts: currentParts
+        });
 
         // Step 1: Thinking (Gemini Flash Lite for low latency)
-        const thinkingResponse = await ai.models.generateContent({
+        const thinkingResponse = await callAIWithRetry(ai.models, {
             model: 'gemini-2.5-flash-lite',
-            contents: { parts: parts },
+            contents: fullContents, // Send full history
             config: {
                 systemInstruction: "你是一位友善、耐心且知识渊博的中小学AI助教。请用简洁、鼓励性的语言回答学生的问题。如果学生使用语音，你也应当在回答中体现出自然的口语风格。",
             }
@@ -140,14 +214,14 @@ app.post('/api/ai/chat', async (req, res) => {
         const answerText = thinkingResponse.text || "抱歉，我没有听清，请再说一遍。";
 
         // Step 2: Speaking (Gemini TTS)
-        const ttsResponse = await ai.models.generateContent({
+        const ttsResponse = await callAIWithRetry(ai.models, {
             model: "gemini-2.5-flash-preview-tts",
             contents: [{ parts: [{ text: answerText }] }],
             config: {
                 responseModalities: [Modality.AUDIO],
                 speechConfig: {
                     voiceConfig: {
-                        prebuiltVoiceConfig: { voiceName: 'Kore' }, // 'Puck', 'Charon', 'Kore', 'Fenrir', 'Zephyr'
+                        prebuiltVoiceConfig: { voiceName: 'Kore' },
                     },
                 },
             },
@@ -157,46 +231,41 @@ app.post('/api/ai/chat', async (req, res) => {
 
         res.json({
             text: answerText,
-            audio: audioBytes // Base64 PCM data
+            audio: audioBytes 
         });
 
     } catch (e) {
         console.error("AI Chat Error:", e);
-        res.status(500).json({ error: e.message });
+        res.status(500).json({ error: e.message || 'AI Service Unavailable' });
     }
 });
 
-// Scenario 2: Evaluation (Question + Audio Answer -> AI Score)
-app.post('/api/ai/evaluate', async (req, res) => {
-    const { question, audio } = req.body;
+// Scenario 2: Evaluation (Question + Audio/Image Answer -> AI Score + Feedback + Audio)
+app.post('/api/ai/evaluate', checkAIAccess, async (req, res) => {
+    const { question, audio, image } = req.body; // Image is base64
 
-    if (!question || !audio) return res.status(400).json({ error: 'Missing question or audio' });
+    if (!question || (!audio && !image)) return res.status(400).json({ error: 'Missing question or input (audio/image)' });
 
     try {
-        // Dynamically import AI
-        const { ai, Type } = await getGenAI();
+        const { ai, Type, Modality } = await getGenAI();
+
+        const evalParts = [{ text: `请作为一名严谨的老师，对学生的回答进行评分。题目是：${question}。` }];
+        
+        if (audio) {
+            evalParts.push({ text: "学生的回答在音频中。" });
+            evalParts.push({ inlineData: { mimeType: 'audio/wav', data: audio } });
+        }
+        if (image) {
+            evalParts.push({ text: "学生的回答写在图片中，请识别图片中的文字内容并进行批改。" });
+            evalParts.push({ inlineData: { mimeType: 'image/jpeg', data: image } });
+        }
+
+        evalParts.push({ text: `请分析：1. 内容准确性 2. 表达/书写规范。返回 JSON: {score(0-100), feedback(简短评语), transcription(识别内容)}` });
 
-        // Evaluate using Multimodal capability
-        const response = await ai.models.generateContent({
+        // 1. Analyze
+        const response = await callAIWithRetry(ai.models, {
             model: 'gemini-2.5-flash-lite',
-            contents: {
-                parts: [
-                    { text: `请作为一名严谨的口语考官，对学生的回答进行评分。
-                             题目是：${question}。
-                             学生的回答在音频中。
-                             请分析学生的：
-                             1. 内容准确性 (是否回答了问题)
-                             2. 语言表达 (流畅度、词汇)
-                             3. 情感/语调
-                             请返回 JSON 格式，包含 score (0-100), feedback (简短评语), transcription (你听到的内容)。` },
-                    {
-                        inlineData: {
-                            mimeType: 'audio/wav',
-                            data: audio
-                        }
-                    }
-                ]
-            },
+            contents: { parts: evalParts },
             config: {
                 responseMimeType: "application/json",
                 responseSchema: {
@@ -211,11 +280,38 @@ app.post('/api/ai/evaluate', async (req, res) => {
             }
         });
 
-        res.json(JSON.parse(response.text));
+        const resultJson = JSON.parse(response.text);
+
+        // 2. Generate Audio for the Feedback (TTS)
+        let feedbackAudio = null;
+        if (resultJson.feedback) {
+            try {
+                const ttsResponse = await callAIWithRetry(ai.models, {
+                    model: "gemini-2.5-flash-preview-tts",
+                    contents: [{ parts: [{ text: resultJson.feedback }] }],
+                    config: {
+                        responseModalities: [Modality.AUDIO],
+                        speechConfig: {
+                            voiceConfig: {
+                                prebuiltVoiceConfig: { voiceName: 'Kore' },
+                            },
+                        },
+                    },
+                });
+                feedbackAudio = ttsResponse.candidates?.[0]?.content?.parts?.[0]?.inlineData?.data;
+            } catch (ttsErr) {
+                console.warn("TTS Generation failed:", ttsErr);
+            }
+        }
+
+        res.json({
+            ...resultJson,
+            audio: feedbackAudio
+        });
 
     } catch (e) {
         console.error("AI Eval Error:", e);
-        res.status(500).json({ error: e.message });
+        res.status(500).json({ error: e.message || 'AI Service Unavailable' });
     }
 });
 

services/api.ts

@@ -1,4 +1,3 @@
-
 // ... existing imports
 import { User, ClassInfo, SystemConfig, Subject, School, Schedule, GameSession, StudentReward, LuckyDrawConfig, Attendance, LeaveRequest, AchievementConfig, SchoolCalendarEntry, TeacherExchangeConfig, Wish, Feedback, AIChatMessage } from '../types';
 
@@ -273,6 +272,6 @@ export const api = {
   // NEW: AI Endpoints
   ai: {
       chat: (data: { text?: string, audio?: string }) => request('/ai/chat', { method: 'POST', body: JSON.stringify(data) }),
-      evaluate: (data: { question: string, audio: string }) => request('/ai/evaluate', { method: 'POST', body: JSON.stringify(data) }),
+      evaluate: (data: { question: string, audio?: string, image?: string }) => request('/ai/evaluate', { method: 'POST', body: JSON.stringify(data) }),
   }
 };

types.ts

@@ -96,7 +96,9 @@ export interface User {
   avatar?: string;
   createTime?: string;
   teachingSubject?: string; 
-  homeroomClass?: string; // 废弃或仅作显示，主要逻辑移至 ClassInfo.homeroomTeacherIds
+  homeroomClass?: string; 
+  // NEW: Feature Flag
+  aiAccess?: boolean;
   // Class Application
   classApplication?: {
     type: 'CLAIM' | 'RESIGN';
@@ -114,6 +116,7 @@ export interface User {
 }
 
 export interface ClassInfo {
+// ... (rest remains same)
   id?: number;
   _id?: string;
   schoolId?: string;
@@ -415,4 +418,4 @@ export interface SchoolCalendarEntry {
   startDate: string; // YYYY-MM-DD
   endDate: string; // YYYY-MM-DD
   name: string;
-}
+}