d8d-admin-mobile-starter-public/client/mobile/pages_classroom.tsx

import React, { useState, useEffect, useRef, createContext, useContext } from 'react';
import AliRtcEngine, { AliRtcSubscribeState, AliRtcVideoTrack, AliRtcSdkChannelProfile } from 'aliyun-rtc-sdk';
import { ToastContainer, toast } from 'react-toastify';

// 从 SDK 中提取需要的类型
type ImEngine = InstanceType<typeof AliVCInteraction.ImEngine>;
type ImGroupManager = AliVCInteraction.AliVCIMGroupManager;
type ImMessageManager = AliVCInteraction.AliVCIMMessageManager;
type ImLogLevel = AliVCInteraction.ImLogLevel;
type ImMessageLevel = AliVCInteraction.ImMessageLevel;

interface ImUser {
  userId: string;
  userExtension?: string;
}

interface ImGroupMessage {
  groupId: string;
  type: number;
  data: string;
  sender?: ImUser;
  timestamp?: number;
}

// 课堂状态枚举
enum ClassStatus {
  NOT_STARTED = 'not_started',
  IN_PROGRESS = 'in_progress',
  ENDED = 'ended'
}

// 课堂上下文类型
// 互动消息类型
type InteractionAction = 'hand_up' | 'cancel_hand_up' | 'answer_hand_up';

// 互动消息基础接口
interface InteractionMessage {
  action: InteractionAction;
  studentId: string;
  studentName?: string;
  timestamp?: number;
  question?: string;
}

// 举手请求类型
interface HandUpRequest extends InteractionMessage {
  timestamp: number;
}

type ClassroomContextType = {
  userId: string;
  role: 'teacher' | 'student';
  isLoggedIn: boolean;
  isJoinedClass: boolean;
  messageList: string[];
  errorMessage: string;
  classStatus: ClassStatus;
  handUpList: HandUpRequest[]; // 举手列表
  questions: string[]; // 问题列表
  setRole: (role: 'teacher' | 'student') => void;
  createClass: (className: string, maxMembers?: number) => Promise<string | null>; // 创建课堂
  startClass: () => Promise<void>;
  endClass: () => Promise<void>;
  toggleMuteMember: (userId: string, mute: boolean) => Promise<void>;
  handUp: (question?: string) => Promise<void>; // 学生举手
  answerHandUp: (studentId: string) => Promise<void>; // 老师应答
  sendQuestion: (question: string) => Promise<void>; // 发送问题
};

const ClassroomContext = createContext<ClassroomContextType | null>(null);

// 辅助函数
function hex(buffer: ArrayBuffer): string {
  const hexCodes = [];
  const view = new DataView(buffer);
  for (let i = 0; i < view.byteLength; i += 4) {
    const value = view.getUint32(i);
    const stringValue = value.toString(16);
    const padding = '00000000';
    const paddedValue = (padding + stringValue).slice(-padding.length);
    hexCodes.push(paddedValue);
  }
  return hexCodes.join('');
}

async function generateToken(
  appId: string,
  appKey: string,
  channelId: string,
  userId: string,
  timestamp: number
): Promise<string> {
  const encoder = new TextEncoder();
  const data = encoder.encode(`${appId}${appKey}${channelId}${userId}${timestamp}`);
  const hash = await crypto.subtle.digest('SHA-256', data);
  return hex(hash);
}

function showToast(type: 'info' | 'success' | 'error', message: string): void {
  switch(type) {
    case 'info':
      toast.info(message);
      break;
    case 'success':
      toast.success(message);
      break;
    case 'error':
      toast.error(message);
      break;
  }
}

// 从SDK获取枚举值
const { ImLogLevel, ImMessageLevel } = window.AliVCInteraction;

// 配置信息
const IM_APP_ID = '4c2ab5e1b1b0';
const IM_APP_KEY = '314bb5eee5b623549e8a41574ba3ff32';
const IM_APP_SIGN = 'H4sIAAAAAAAE/wCQAG//zguHB+lYCilkv7diSkk4GmcvLuds+InRu9vFOFebMwm/jEgsK5bBT85Z0owObMxG58uXHyPFlPEBEDQm9FswNJ+KmX0VDYkcfdPPWkafA6Hc0B6F+p5De9yJfPEfHzwo/DHMaygbHfLmBgUtmKveq421sJr/gNBz9D04Ewsg39us+ao0NegzLt7xtXvFXXXJAAAA//8BAAD//yoav6aQAAAA';
const RTC_APP_ID = 'a5842c2a-d94a-43be-81de-1fdb712476e1';
const RTC_APP_KEY = 'b71d65f4f84c450f6f058f4ad507bd42';

// IM Token生成
async function generateImToken(userId: string, role: string): Promise<string> {
    const nonce = 'AK_4';
    const timestamp = Math.floor(Date.now() / 1000) + 3600 * 3;
    const pendingShaStr = `${IM_APP_ID}${IM_APP_KEY}${userId}${nonce}${timestamp}${role}`;
    const encoder = new TextEncoder();
    const data = encoder.encode(pendingShaStr);
    const hash = await crypto.subtle.digest('SHA-256', data);
    return hex(hash);
}

export const ClassroomPage = () => {
  // 状态管理
  const [userId, setUserId] = useState<string>('');
  const [className, setClassName] = useState<string>('');
  const [role, setRole] = useState<'teacher' | 'student'>('student');
  const [classId, setClassId] = useState<string>('');
  const [isLoggedIn, setIsLoggedIn] = useState<boolean>(false);
  const [isJoinedClass, setIsJoinedClass] = useState<boolean>(false);
  const [msgText, setMsgText] = useState<string>('');
  const [messageList, setMessageList] = useState<string[]>([]);
  const [errorMessage, setErrorMessage] = useState<string>('');
  const [classStatus, setClassStatus] = useState<ClassStatus>(ClassStatus.NOT_STARTED);
  const [handUpList, setHandUpList] = useState<HandUpRequest[]>([]);
  const [questions, setQuestions] = useState<string[]>([]);

  // SDK实例
  const imEngine = useRef<ImEngine | null>(null);
  const imGroupManager = useRef<ImGroupManager | null>(null);
  const imMessageManager = useRef<ImMessageManager | null>(null);
  const aliRtcEngine = useRef<AliRtcEngine | null>(null);
  const remoteVideoElMap = useRef<Record<string, HTMLVideoElement>>({});
  const remoteVideoContainer = useRef<HTMLDivElement>(null);

  // 消息管理模块
  const showMessage = (text: string): void => {
    setMessageList([...messageList, text]);
  };

  const listenImEvents = (): void => {
    if (!imEngine.current) return;

    imEngine.current.on('connectsuccess', () => {
      showMessage('IM连接成功');
    });

    imEngine.current.on('disconnect', async (code: number) => {
      showMessage(`IM断开连接: ${code}`);
      // 自动重连
      try {
        const imToken = await generateImToken(userId, role);
        await imEngine.current!.login({
          user: {
            userId,
            userExtension: '{}'
          },
          userAuth: {
            nonce: 'AK_4',
            timestamp: Math.floor(Date.now() / 1000) + 3600 * 3,
            token: imToken,
            role
          }
        });
        showMessage('IM自动重连成功');
      } catch (err: unknown) {
        const error = err as Error;
        showMessage(`IM自动重连失败: ${error.message}`);
      }
    });
  };

  const listenGroupEvents = (): void => {
    if (!imGroupManager.current) return;

    imGroupManager.current.on('memberchange', (groupId: string, memberCount: number, joinUsers: ImUser[], leaveUsers: ImUser[]) => {
      showMessage(`成员变更: 加入${joinUsers.length}人, 离开${leaveUsers.length}人`);
    });
  };

  const listenMessageEvents = (): void => {
    if (!imMessageManager.current) return;

    imMessageManager.current.on('recvgroupmessage', (msg: AliVCInteraction.ImMessage, groupId: string) => {
      if (msg.type === 88889) { // 课堂状态消息
        try {
          const data = JSON.parse(msg.data);
          if (data.action === 'start_class') {
            setClassStatus(ClassStatus.IN_PROGRESS);
            showMessage('老师已开始上课');
          } else if (data.action === 'end_class') {
            setClassStatus(ClassStatus.ENDED);
            showMessage('老师已结束上课');
          }
        } catch (err) {
          console.error('解析课堂状态消息失败', err);
        }
      } else if (msg.type === 88890) { // 静音指令
        try {
          const data = JSON.parse(msg.data);
          if (data.action === 'toggle_mute' && data.userId === userId) {
            showMessage(data.mute ? '你已被老师静音' : '老师已取消你的静音');
          }
        } catch (err) {
          console.error('解析静音指令失败', err);
        }
      } else if (msg.type === 88891) { // 举手消息
        try {
          const data = JSON.parse(msg.data) as InteractionMessage;
          if (data.action === 'hand_up') {
            const handUpData: HandUpRequest = {
              ...data,
              timestamp: data.timestamp || Date.now()
            };
            setHandUpList([...handUpList, handUpData]);
            showMessage(`${data.studentName || data.studentId} 举手了`);
          } else if (data.action === 'cancel_hand_up') {
            setHandUpList(handUpList.filter(h => h.studentId !== data.studentId));
          }
        } catch (err) {
          console.error('解析举手消息失败', err);
        }
      } else if (msg.type === 88892) { // 问题消息
        try {
          const data = JSON.parse(msg.data) as {question: string};
          setQuestions([...questions, data.question]);
          showMessage(`收到问题: ${data.question}`);
        } catch (err) {
          console.error('解析问题消息失败', err);
        }
      } else if (msg.type === 88893) { // 应答消息
        try {
          const data = JSON.parse(msg.data) as InteractionMessage;
          if (data.action === 'answer_hand_up' && data.studentId === userId) {
            showMessage('老师已应答你的举手');
            setHandUpList(handUpList.filter(h => h.studentId !== data.studentId));
          }
        } catch (err) {
          console.error('解析应答消息失败', err);
        }
      }
    });
  };

  // 音视频模块
  const removeRemoteVideo = (userId: string, type: 'camera' | 'screen' = 'camera') => {
    const vid = `${type}_${userId}`;
    const el = remoteVideoElMap.current[vid];
    if (el) {
      aliRtcEngine.current!.setRemoteViewConfig(null, userId, type === 'camera' ? AliRtcVideoTrack.AliRtcVideoTrackCamera : AliRtcVideoTrack.AliRtcVideoTrackScreen);
      el.pause();
      remoteVideoContainer.current?.removeChild(el);
      delete remoteVideoElMap.current[vid];
    }
  };

  const listenRtcEvents = () => {
    if (!aliRtcEngine.current) return;

    aliRtcEngine.current.on('remoteUserOnLineNotify', (userId: string) => {
      showMessage(`用户 ${userId} 加入课堂`);
    });

    aliRtcEngine.current.on('remoteUserOffLineNotify', (userId: string) => {
      showMessage(`用户 ${userId} 离开课堂`);
      removeRemoteVideo(userId, 'camera');
      removeRemoteVideo(userId, 'screen');
    });
  };

  // 统一登录逻辑
  const login = async (userId: string): Promise<void> => {
    try {
      // 初始化IM
      const { ImEngine: ImEngineClass } = window.AliVCInteraction;
      imEngine.current = ImEngineClass.createEngine();
      await imEngine.current.init({
        deviceId: 'xxxx',
        appId: IM_APP_ID,
        appSign: IM_APP_SIGN,
        logLevel: ImLogLevel.ERROR,
      });

      // 登录IM
      const imToken = await generateImToken(userId, role);
      await imEngine.current.login({
        user: {
          userId,
          userExtension: '{}'
        },
        userAuth: {
          nonce: 'AK_4',
          timestamp: Math.floor(Date.now() / 1000) + 3600 * 3,
          token: imToken,
          role
        }
      });
      
      // 初始化RTC
      aliRtcEngine.current = AliRtcEngine.getInstance();
      AliRtcEngine.setLogLevel(0);
      
      // 设置事件监听
      listenImEvents();
      listenRtcEvents();
      
      setIsLoggedIn(true);
      setErrorMessage('');
      showToast('success', '登录成功');
    } catch (err: any) {
      setErrorMessage(`登录失败: ${err.message}`);
      showToast('error', '登录失败');
    }
  };

  // 加入课堂
  const joinClass = async (classId: string): Promise<void> => {
    if (!imEngine.current || !aliRtcEngine.current) return;

    try {
      // 加入IM群组
      const gm = imEngine.current.getGroupManager();
      const mm = imEngine.current.getMessageManager();
      imGroupManager.current = gm || null;
      imMessageManager.current = mm || null;
      await gm!.joinGroup(classId);
      listenGroupEvents();
      listenMessageEvents();

      // 加入RTC频道
      const timestamp = Math.floor(Date.now() / 1000) + 3600 * 3;
      const token = await generateToken(RTC_APP_ID, RTC_APP_KEY, classId, userId, timestamp);
      aliRtcEngine.current.setChannelProfile(AliRtcSdkChannelProfile.AliRtcSdkCommunication);
      await aliRtcEngine.current.joinChannel(
        {
          channelId: classId,
          userId,
          appId: RTC_APP_ID,
          token,
          timestamp,
        },
        userId
      );

      // 设置本地预览
      aliRtcEngine.current.setLocalViewConfig('localPreviewer', AliRtcVideoTrack.AliRtcVideoTrackCamera);
      
      setIsJoinedClass(true);
      setErrorMessage('');
      showToast('success', '加入课堂成功');
    } catch (err: any) {
      setErrorMessage(`加入课堂失败: ${err.message}`);
      showToast('error', '加入课堂失败');
    }
  };

  // 离开课堂
  const leaveClass = async (): Promise<void> => {
    if (imGroupManager.current && classId) {
      await imGroupManager.current.leaveGroup(classId);
    }
    if (aliRtcEngine.current) {
      await aliRtcEngine.current.leaveChannel();
    }
    
    setIsJoinedClass(false);
    showToast('info', '已离开课堂');
  };

  // 发送消息
  const sendMessage = async (): Promise<void> => {
    if (!imMessageManager.current || !classId) return;

    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: msgText,
        type: 88888,
        level: ImMessageLevel.NORMAL,
      });
      setMsgText('');
      setErrorMessage('');
    } catch (err: any) {
      setErrorMessage(`消息发送失败: ${err.message}`);
    }
  };

  // 开始上课
  const startClass = async (): Promise<void> => {
    if (!imMessageManager.current || !classId || role !== 'teacher') return;
    
    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: JSON.stringify({ action: 'start_class' }),
        type: 88889, // 自定义消息类型
        level: ImMessageLevel.HIGH,
      });
      setClassStatus(ClassStatus.IN_PROGRESS);
      showToast('success', '课堂已开始');
    } catch (err: any) {
      setErrorMessage(`开始上课失败: ${err.message}`);
    }
  };

  // 结束上课
  const endClass = async (): Promise<void> => {
    if (!imMessageManager.current || !classId || role !== 'teacher') return;
    
    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: JSON.stringify({ action: 'end_class' }),
        type: 88889, // 自定义消息类型
        level: ImMessageLevel.HIGH,
      });
      setClassStatus(ClassStatus.ENDED);
      showToast('success', '课堂已结束');
    } catch (err: any) {
      setErrorMessage(`结束上课失败: ${err.message}`);
    }
  };

  // 静音/取消静音成员
  const toggleMuteMember = async (userId: string, mute: boolean): Promise<void> => {
    if (!imMessageManager.current || !classId || role !== 'teacher') return;
    
    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: JSON.stringify({
          action: 'toggle_mute',
          userId,
          mute
        }),
        type: 88890, // 自定义消息类型
        level: ImMessageLevel.HIGH,
      });
      showToast('info', mute ? `已静音用户 ${userId}` : `已取消静音用户 ${userId}`);
    } catch (err: any) {
      setErrorMessage(`操作失败: ${err.message}`);
    }
  };

  // 创建课堂
  const createClass = async (className: string, maxMembers = 200): Promise<string | null> => {
    if (!imEngine.current || !isLoggedIn || role !== 'teacher') {
      showToast('error', '只有老师可以创建课堂');
      return null;
    }
    
    try {
      const groupManager = imEngine.current.getGroupManager();
      if (!groupManager) {
        throw new Error('群组管理器未初始化');
      }

      // 显示创建中状态
      showToast('info', '正在创建课堂...');
      
      // 调用IM SDK创建群组
      const response = await groupManager.createGroup({
        groupName: className,
        groupMeta: JSON.stringify({
          classType: 'interactive',
          creator: userId,
          createdAt: Date.now(),
          maxMembers
        })
      });

      if (!response?.groupId) {
        throw new Error('创建群组失败: 未返回群组ID');
      }

      // 创建成功后自动加入群组
      try {
        await groupManager.joinGroup(response.groupId);
        showToast('success', '课堂创建并加入成功');
        showMessage(`课堂 ${className} 创建成功，ID: ${response.groupId}`);
        
        // 更新状态
        setClassId(response.groupId);
        setIsJoinedClass(true);
        
        // 初始化群组消息管理器
        const messageManager = imEngine.current.getMessageManager();
        if (messageManager) {
          imMessageManager.current = messageManager;
          listenMessageEvents();
        }
        
        // 记录创建时间
        const createTime = new Date();
        showMessage(`创建时间: ${createTime.toLocaleString()}`);
        
        return response.groupId;
      } catch (joinErr: any) {
        throw new Error(`创建成功但加入失败: ${joinErr.message}`);
      }
    } catch (err: any) {
      const errorMsg = err.message.includes('alreadyExist')
        ? '课堂已存在'
        : `课堂创建失败: ${err.message}`;
      
      setErrorMessage(errorMsg);
      showToast('error', errorMsg);
      return null;
    }
  };

  // 清理资源
  useEffect(() => {
    return () => {
      if (imGroupManager.current) {
        imGroupManager.current.removeAllListeners();
      }
      if (imMessageManager.current) {
        imMessageManager.current.removeAllListeners();
      }
      if (imEngine.current) {
        imEngine.current.removeAllListeners();
      }
      if (aliRtcEngine.current) {
        aliRtcEngine.current.destroy();
      }
    };
  }, []);

  // 学生举手
  const handUp = async (question?: string): Promise<void> => {
    if (!imMessageManager.current || !classId || role !== 'student') return;
    
    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: JSON.stringify({
          action: 'hand_up',
          studentId: userId,
          timestamp: Date.now(),
          question
        }),
        type: 88891,
        level: ImMessageLevel.NORMAL,
      });
    } catch (err: any) {
      setErrorMessage(`举手失败: ${err.message}`);
    }
  };

  // 老师应答举手
  const answerHandUp = async (studentId: string): Promise<void> => {
    if (!imMessageManager.current || !classId || role !== 'teacher') return;
    
    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: JSON.stringify({
          action: 'answer_hand_up',
          studentId
        }),
        type: 88893,
        level: ImMessageLevel.HIGH,
      });
    } catch (err: any) {
      setErrorMessage(`应答失败: ${err.message}`);
    }
  };

  // 发送问题
  const sendQuestion = async (question: string): Promise<void> => {
    if (!imMessageManager.current || !classId) return;
    
    try {
      await imMessageManager.current.sendGroupMessage({
        groupId: classId,
        data: question,
        type: 88892,
        level: ImMessageLevel.NORMAL,
      });
    } catch (err: any) {
      setErrorMessage(`问题发送失败: ${err.message}`);
    }
  };

  return (
    <ClassroomContext.Provider value={{
      userId,
      role,
      isLoggedIn,
      isJoinedClass,
      messageList,
      errorMessage,
      classStatus,
      handUpList,
      questions,
      setRole,
      createClass,
      startClass,
      endClass,
      toggleMuteMember,
      handUp,
      answerHandUp,
      sendQuestion
    }}>
      <div className="container mx-auto p-4">
        <h1 className="text-2xl font-bold mb-4">互动课堂</h1>
        
        <ToastContainer
          position="top-right"
          autoClose={5000}
          hideProgressBar={false}
          newestOnTop={false}
          closeOnClick
          rtl={false}
          pauseOnFocusLoss
          draggable
          pauseOnHover
        />

        <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
          <div className="md:col-span-1">
            <form>
              {!isLoggedIn && (
                <div className="mb-2">
                  <label className="block text-sm font-medium text-gray-700">课堂名称</label>
                  <input
                    className="mt-1 block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm"
                    value={className}
                    onChange={(e) => setClassName(e.target.value)}
                    placeholder="输入课堂名称"
                  />
                </div>
              )}
              <div className="mb-2">
                <label className="block text-sm font-medium text-gray-700">用户ID</label>
                <input
                  className="mt-1 block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm"
                  value={userId}
                  onChange={(e) => setUserId(e.target.value)}
                />
              </div>
              
              <div className="mb-2">
                <label className="block text-sm font-medium text-gray-700">课堂ID</label>
                <input
                  className="mt-1 block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm"
                  value={classId}
                  onChange={(e) => setClassId(e.target.value)}
                />
              </div>
              
              <div className="mb-2">
                <label className="block text-sm font-medium text-gray-700">角色</label>
                <select
                  className="mt-1 block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm"
                  value={role}
                  onChange={(e) => setRole(e.target.value as 'teacher' | 'student')}
                >
                  <option value="student">学生</option>
                  <option value="teacher">老师</option>
                </select>
              </div>
              
              <div className="flex space-x-2 mb-2">
                {!isLoggedIn && (
                  <button
                    type="button"
                    className="px-3 py-2 bg-green-600 text-white rounded-md"
                    disabled={!className}
                    onClick={async () => {
                      const classId = await createClass(className);
                      if (classId) {
                        setClassId(classId);
                      }
                    }}
                  >
                    创建课堂
                  </button>
                )}
                <button
                  type="button"
                  className="px-3 py-2 bg-blue-600 text-white rounded-md"
                  disabled={isLoggedIn}
                  onClick={() => login(userId)}
                >
                  登录
                </button>
                
                <button
                  type="button"
                  className="px-3 py-2 bg-blue-600 text-white rounded-md"
                  disabled={!isLoggedIn || isJoinedClass}
                  onClick={() => joinClass(classId)}
                >
                  加入课堂
                </button>
                
                <button
                  type="button"
                  className="px-3 py-2 bg-gray-600 text-white rounded-md"
                  disabled={!isJoinedClass}
                  onClick={leaveClass}
                >
                  离开课堂
                </button>
              </div>
            </form>
            
            <div className="mt-4">
              <label className="block text-sm font-medium text-gray-700">消息</label>
              <input
                className="mt-1 block w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm"
                value={msgText}
                onChange={(e) => setMsgText(e.target.value)}
              />
              <button
                type="button"
                className="mt-2 px-3 py-2 bg-blue-600 text-white rounded-md"
                disabled={!isJoinedClass}
                onClick={sendMessage}
              >
                发送
              </button>
            </div>
            
            {role === 'student' && isJoinedClass && (
              <div className="mt-4 p-4 bg-white rounded-md shadow">
                <h4 className="text-lg font-medium mb-2">互动功能</h4>
                <div className="space-y-3">
                  <button
                    type="button"
                    className="w-full px-3 py-2 bg-green-600 text-white rounded-md"
                    onClick={() => handUp()}
                  >
                    举手
                  </button>
                  <div className="flex space-x-2">
                    <input
                      type="text"
                      placeholder="输入问题..."
                      className="flex-1 px-3 py-2 border border-gray-300 rounded-md"
                      id="questionInput"
                    />
                    <button
                      type="button"
                      className="px-3 py-2 bg-blue-600 text-white rounded-md"
                      onClick={() => {
                        const input = document.getElementById('questionInput') as HTMLInputElement;
                        if (input.value) {
                          sendQuestion(input.value);
                          input.value = '';
                        }
                      }}
                    >
                      提问
                    </button>
                  </div>
                </div>
              </div>
            )}
            
            {role === 'teacher' && handUpList.length > 0 && (
              <div className="mt-4 p-4 bg-white rounded-md shadow">
                <h4 className="text-lg font-medium mb-2">举手列表 ({handUpList.length})</h4>
                <div className="space-y-2">
                  {handUpList.map((req, i) => (
                    <div key={i} className="flex items-center justify-between p-2 border-b">
                      <div>
                        <div className="font-medium">{req.studentName || req.studentId}</div>
                        {req.question && <div className="text-sm text-gray-500">{req.question}</div>}
                      </div>
                      <button
                        type="button"
                        className="px-2 py-1 bg-blue-600 text-white rounded text-sm"
                        onClick={() => answerHandUp(req.studentId)}
                      >
                        应答
                      </button>
                    </div>
                  ))}
                </div>
              </div>
            )}
            
            {questions.length > 0 && (
              <div className="mt-4 p-4 bg-white rounded-md shadow">
                <h4 className="text-lg font-medium mb-2">问题列表 ({questions.length})</h4>
                <div className="space-y-2">
                  {questions.map((q, i) => (
                    <div key={i} className="p-2 border-b">
                      <div className="font-medium">问题 {i + 1}</div>
                      <div className="text-gray-700">{q}</div>
                    </div>
                  ))}
                </div>
              </div>
            )}
          </div>
          
          <div className="md:col-span-1">
            <h4 className="text-lg font-medium mb-2">消息记录</h4>
            <div className="bg-gray-100 p-2 rounded-md h-64 overflow-y-auto">
              {messageList.map((msg, i) => (
                <div key={i} className="mb-1">{msg}</div>
              ))}
            </div>

            {role === 'teacher' && isJoinedClass && (
              <div className="mt-4 p-4 bg-white rounded-md shadow">
                <h4 className="text-lg font-medium mb-2">老师控制面板</h4>
                <div className="flex space-x-2 mb-4">
                  <button
                    type="button"
                    className="px-3 py-2 bg-green-600 text-white rounded-md"
                    disabled={classStatus === ClassStatus.IN_PROGRESS}
                    onClick={startClass}
                  >
                    开始上课
                  </button>
                  <button
                    type="button"
                    className="px-3 py-2 bg-red-600 text-white rounded-md"
                    disabled={classStatus !== ClassStatus.IN_PROGRESS}
                    onClick={endClass}
                  >
                    结束上课
                  </button>
                </div>
                <div>
                  <h5 className="font-medium mb-2">成员管理</h5>
                  <div className="space-y-2">
                    <div className="flex items-center justify-between">
                      <span>学生A</span>
                      <button
                        type="button"
                        className="px-2 py-1 bg-yellow-500 text-white rounded text-sm"
                        onClick={() => toggleMuteMember('studentA', true)}
                      >
                        静音
                      </button>
                    </div>
                    <div className="flex items-center justify-between">
                      <span>学生B</span>
                      <button
                        type="button"
                        className="px-2 py-1 bg-blue-500 text-white rounded text-sm"
                        onClick={() => toggleMuteMember('studentB', false)}
                      >
                        取消静音
                      </button>
                    </div>
                  </div>
                </div>
              </div>
            )}
          </div>
          
          <div className="md:col-span-1">
            <h4 className="text-lg font-medium mb-2">视频区域</h4>
            <video
              id="localPreviewer"
              muted
              className="w-full h-48 bg-black mb-2"
            ></video>
            <div
              id="remoteVideoContainer"
              ref={remoteVideoContainer}
              className="grid grid-cols-2 gap-2"
            ></div>
          </div>
        </div>
        
        {errorMessage && (
          <div className="mt-2 text-red-500">{errorMessage}</div>
        )}
      </div>
    </ClassroomContext.Provider>
  );
};