/**
 * 状态管理
 * 使用简单的 Observable 模式，可替换为 Redux/Vuex/Pinia
 */
import { mockCallSession, mockMessages } from './models.js';
import { Signaling, WebSocketSignaling } from "../../module/signaling.js";// 信令管理
import { RenderStreaming } from "../../module/renderstreaming.js"; // WebRTC连接管理
import { getServerConfig, getRTCConfiguration } from "../js/config.js";//服务器配置和RTC配置
import { showNotification } from './utils.js'; // 导入通知函数
// 默认视频流尺寸
const defaultStreamWidth = 1280;
const defaultStreamHeight = 720;



class CallStateManager {
    constructor() {
        const renderstreaming=null; // WebRTC连接管理实例
        const useWebSocket=null; // 是否使用WebSocket信令
        const connectionId=null; // 连接ID
        // 核心状态
        this.state = {
            session: {
                ...mockCallSession,
                status: 'idle' // 初始状态为空闲
            },
            messages: [...mockMessages],
            isSidebarOpen: false,
            unreadCount: 0,
            localStream: null,  // MediaStream 对象
            remoteStream: null  // MediaStream 对象
        };

        // 监听器数组
        this.listeners = [];
    }

    // 订阅状态变化
    subscribe(callback) {
        this.listeners.push(callback);
        return () => {
            this.listeners = this.listeners.filter(cb => cb !== callback);
        };
    }

    // 通知所有监听器
    notify(changes) {
        this.listeners.forEach(cb => cb(this.state, changes));
    }

    // 初始化
    async init() {
        // 启动通话时长计时器
        this.durationInterval = setInterval(() => {
            this.state.session.duration++;
            this.notify({ type: 'DURATION_UPDATE', duration: this.state.session.duration });
        }, 1000);
        // 初始化配置
        await this.setupConfig();
        // 获取本地摄像头视频流
        await this.getLocalStream();

        // 模拟远端音频活动 (实际应由 WebRTC VAD 检测触发)
        //this.simulateRemoteActivity();

        // 模拟网络质量变化
        this.simulateNetworkChange();
    }
    async setupConfig() {
        const res = await getServerConfig();
        this.useWebSocket = res.useWebSocket;
    }
    // 获取本地摄像头视频流
    async getLocalStream() {
        try {
            console.log('Requesting camera permission...');

            // 检查浏览器是否支持getUserMedia
            if (!navigator.mediaDevices || !navigator.mediaDevices.getUserMedia) {
                console.error('getUserMedia is not supported');
                throw new Error('getUserMedia is not supported');
            }

            // 请求摄像头权限并获取媒体流
            const stream = await navigator.mediaDevices.getUserMedia({
                video: true,
                audio: true
            });

            console.log('Stream obtained successfully:', stream);
            console.log('Video tracks:', stream.getVideoTracks());
            console.log('Audio tracks:', stream.getAudioTracks());

            this.state.localStream = stream;
            this.state.session.localUser.mediaState.video = true;
            this.state.session.localUser.mediaState.audio = true;

            console.log('Local stream stored, notifying UI...');

            // 先通知视频流已获取
            this.notify({ type: 'LOCAL_STREAM_OBTAINED', stream });
            // 再通知媒体状态变化
            this.notify({ type: 'LOCAL_MEDIA_CHANGE', mediaType: 'video', value: true });
            this.notify({ type: 'LOCAL_MEDIA_CHANGE', mediaType: 'audio', value: true });

            // 发送媒体状态到服务器
            this.emitMediaStateChange();
        } catch (error) {
            console.error('Error getting local stream:', error);
            // 如果获取视频失败，保持视频关闭状态
            this.state.session.localUser.mediaState.video = false;
            this.state.session.localUser.mediaState.audio = false;

            // 通知媒体状态变化
            this.notify({ type: 'LOCAL_MEDIA_CHANGE', mediaType: 'video', value: false });
            this.notify({ type: 'LOCAL_MEDIA_CHANGE', mediaType: 'audio', value: false });
        }
    }

    // 更新本地媒体状态
    async updateLocalMedia(mediaType, value) {

        // 如果是开启视频，重新获取摄像头资源
        if (mediaType === 'video' && value) {
            if (this.state.localStream) {
                this.state.localStream = null;
            }
            //if(this.state.localStream.getVideoTracks().length==0){
            // 请求摄像头权限并获取媒体流
            this.state.localStream = await navigator.mediaDevices.getUserMedia({
                video: true,
                audio: true
            });
            // }
            await this.getLocalStream();
        } else {
            // 直接更新媒体状态
            this.state.session.localUser.mediaState[mediaType] = value;
            this.notify({ type: 'LOCAL_MEDIA_CHANGE', mediaType, value });

            // 发送媒体状态到服务器
            this.emitMediaStateChange();
        }


        // 如果是关闭视频，释放摄像头资源
        if (mediaType === 'video' && !value && this.state.localStream) {
            this.state.localStream.getTracks().forEach(track => {
                if (track.kind === 'video') {
                    track.stop();
                }
            });

        }

        // 如果是音频状态变化，控制本地音频轨道
        if (mediaType === 'audio' && this.state.localStream) {
            this.state.localStream.getTracks().forEach(track => {
                if (track.kind === 'audio') {
                    track.enabled = value;
                }
            });
        }


    }
    /**
     * 设置WebRTC连接
     * @async
     * @returns {Promise<void>}
     */
    async setUp(connectionId) {
        //TODO
        this.connectionId = connectionId; // 获取连接ID
        // 设置状态为连接中
        this.state.session.status = 'connecting';
        this.notify({ type: 'CALL_STATUS_CHANGE', status: 'connecting' });
        // 确保本地流已经初始化
        if (!this.state.localStream) {
            console.log('Local stream not available, waiting for initialization...');
            // 等待localStream初始化
            await new Promise((resolve) => {
                const checkStream = () => {
                    if (this.state.localStream) {
                        resolve();
                    } else {
                        setTimeout(checkStream, 100);
                    }
                };
                checkStream();
            });
        }

        // 创建信令实例
        const signaling = this.useWebSocket ? new WebSocketSignaling() : new Signaling();
        const config = getRTCConfiguration(); // 获取RTC配置
        this.renderstreaming = new RenderStreaming(signaling, config); // 创建WebRTC连接管理实例

        // 连接建立回调
        this.renderstreaming.onConnect = () => {
            // 连接建立后，更新状态为ongoing
        this.state.session.status = 'ongoing';
        this.notify({ type: 'CALL_STATUS_CHANGE', status: 'ongoing' });
        
            if (this.state.localStream) {
                const tracks = this.state.localStream.getTracks(); // 获取本地媒体轨道
                for (const track of tracks) {
                    this.renderstreaming.addTransceiver(track, { direction: 'sendonly' }); // 添加发送轨道
                }
                this.setCodecPreferences(); // 设置编解码器偏好
                this.showStatsMessage(); // 显示统计信息
            } else {
                console.error('Local stream is not available');
                showNotification('本地视频流不可用', 'error');
            }
        };

        // 连接断开回调
        this.renderstreaming.onDisconnect = () => {
            this.hangUp(); // 挂断连接
        };

        // 轨道事件回调
        this.renderstreaming.onTrackEvent = (data) => {
            const direction = data.transceiver.direction;
            if (direction == "sendrecv" || direction == "recvonly") {
                if (this.state.remoteStream == null) {
                    this.state.remoteStream = new MediaStream();
                }
                this.state.remoteStream.addTrack(data.track);
                // 通知UI远程流已更新
                this.notify({ type: 'REMOTE_STREAM_OBTAINED', stream: this.state.remoteStream });
            }
        };

        // 启动WebRTC连接
        await this.renderstreaming.start();
        await this.renderstreaming.createConnection(connectionId);

    }

    /**
 * 挂断WebRTC连接
 * @async
 * @returns {Promise<void>}
 */
    async hangUp() {
        this.clearStatsMessage(); // 清除统计信息
        this.messageDiv.style.display = 'block';
        this.messageDiv.innerText = `Disconnect peer on ${this.connectionId}.`;

        // 删除连接并停止WebRTC
        await this.renderstreaming.deleteConnection();
        await this.renderstreaming.stop();
        this.renderstreaming = null;
        this.remoteVideo.srcObject = null; // 清除远程视频源

        this.connectionId = null;

        // 启用编解码器选择
        if (this.supportsSetCodecPreferences) {
            this.codecPreferences.disabled = false;
        }
    }
    /**
     * 设置编解码器偏好
     */
    setCodecPreferences() {
        /** @type {RTCRtpCodecCapability[] | null} */
        let selectedCodecs = null;

        if (this.supportsSetCodecPreferences) {
            const preferredCodec = this.codecPreferences.options[this.codecPreferences.selectedIndex];
            if (preferredCodec.value !== '') {
                const [mimeType, sdpFmtpLine] = preferredCodec.value.split(' ');
                const { codecs } = RTCRtpSender.getCapabilities('video');
                const selectedCodecIndex = codecs.findIndex(c => c.mimeType === mimeType && c.sdpFmtpLine === sdpFmtpLine);
                const selectCodec = codecs[selectedCodecIndex];
                selectedCodecs = [selectCodec];
            }
        }

        if (selectedCodecs == null) {
            return;
        }

        // 获取视频收发器并设置编解码器偏好
        const transceivers = this.renderstreaming.getTransceivers().filter(t => t.receiver.track.kind == "video");
        if (transceivers && transceivers.length > 0) {
            transceivers.forEach(t => t.setCodecPreferences(selectedCodecs));
        }
    }


    // 更新远端媒体状态 (由 WebSocket 消息触发)
    updateRemoteMedia(mediaState) {
        this.state.session.remoteUser.mediaState = {
            ...this.state.session.remoteUser.mediaState,
            ...mediaState
        };
        this.notify({ type: 'REMOTE_MEDIA_CHANGE', mediaState });
    }

    // 添加消息
    addMessage(message) {
        this.state.messages.push(message);

        // 如果侧边栏关闭且不是自己发的，增加未读
        if (!this.state.isSidebarOpen && !message.isSelf) {
            this.state.unreadCount++;
        }

        this.notify({ type: 'NEW_MESSAGE', message, unreadCount: this.state.unreadCount });
    }

    // 切换侧边栏
    toggleSidebar() {
        this.state.isSidebarOpen = !this.state.isSidebarOpen;
        if (this.state.isSidebarOpen) {
            this.state.unreadCount = 0;
        }
        this.notify({ type: 'SIDEBAR_TOGGLE', isOpen: this.state.isSidebarOpen });
    }

    // 结束通话
    endCall() {
        clearInterval(this.durationInterval);
        this.state.session.status = 'ended';
        this.notify({ type: 'CALL_ENDED' });

        // 发送结束通话请求到服务器
        // [API_CALL: POST /api/call/:callId/leave]
        // [WEBSOCKET_EMIT: leave-call]
    }

    // 加入通话
    async joinCall(connectionId) {
        this.state.session.status = 'connecting';
        this.notify({ type: 'CALL_STATUS_CHANGE', status: 'connecting' });
        showNotification(`正在加入通话 (${connectionId})`);

        // 初始化
        await this.init();

        // 保存连接ID
        this.connectionId = connectionId;
    }

    // 创建通话
    async createCall() {
        this.state.session.status = 'connecting';
        this.notify({ type: 'CALL_STATUS_CHANGE', status: 'connecting' });
        showNotification('正在创建通话...');

        // 初始化
        await this.init();
    }

    // 模拟远端活动 (开发测试用)
    simulateRemoteActivity() {
        setInterval(() => {
            if (Math.random() > 0.7) {
                const isSpeaking = Math.random() > 0.5;
                this.updateRemoteMedia({ isSpeaking });
            }
        }, 800);
    }

    // 模拟网络质量变化 (开发测试用)
    simulateNetworkChange() {
        const qualities = ['excellent', 'good', 'fair', 'poor'];
        setInterval(() => {
            if (Math.random() > 0.8) {
                const quality = qualities[Math.floor(Math.random() * qualities.length)];
                this.state.session.remoteUser.networkQuality = quality;
                this.notify({ type: 'NETWORK_CHANGE', quality });
            }
        }, 5000);
    }

    // 发送媒体状态到服务器
    emitMediaStateChange() {
        const payload = {
            userId: this.state.session.localUser.id,
            ...this.state.session.localUser.mediaState
        };
        console.log('[WebSocket Emit] media-state-changed:', payload);
        // socket.emit('media-state-changed', payload);
    }

    // 显示统计信息
    showStatsMessage() {
        console.log('Showing stats message');
        // 这里可以添加显示统计信息的逻辑
    }

    // 清除统计信息
    clearStatsMessage() {
        console.log('Clearing stats message');
        // 这里可以添加清除统计信息的逻辑
    }

    // Getters
    getState() { return this.state; }
    getLocalUser() { return this.state.session.localUser; }
    getRemoteUser() { return this.state.session.remoteUser; }
    getMessages() { return this.state.messages; }
    getConnectionId() { return this.connectionId; }
}

// 创建单例实例
const store = new CallStateManager();

// 页面卸载前清理
window.addEventListener('beforeunload', async () => {
    if (!store.renderstreaming)
        return;
    await store.renderstreaming.stop(); // 停止WebRTC连接
}, true);
export default store;