/**
 * WebSocket客户端服务
 * 提供WebSocket连接管理、心跳机制、消息处理等功能
 * 集成JWT token解析，支持自动获取用户登录名
 * 
 * @author hongawen
 * @version 2.0
 */

import { ElMessage } from "element-plus";
import { jwtUtil } from "./jwtUtil";

// ============================================================================
// 类型定义 (Types & Interfaces)
// ============================================================================

/**
 * WebSocket消息接口定义（对应后端WebSocketVO结构）
 */
interface WebSocketMessage<T = any> {
    type: string;           // 消息类型
    requestId?: string;     // 请求ID
    operateCode?: string;   // 操作代码
    code?: number;          // 状态码
    desc?: string;          // 描述信息
    data?: T;              // 泛型数据
}

/**
 * 回调函数类型定义
 */
type CallbackFunction<T = any> = (message: WebSocketMessage<T>) => void;

/**
 * WebSocket配置接口
 */
interface SocketConfig {
    url: string;                    // WebSocket服务器地址
    heartbeatInterval?: number;     // 心跳间隔时间(ms)
    reconnectDelay?: number;        // 重连延迟时间(ms)
    maxReconnectAttempts?: number;  // 最大重连次数
    timeout?: number;               // 超时时间(ms)
}

/**
 * 连接状态枚举
 */
enum ConnectionStatus {
    DISCONNECTED = 'disconnected',   // 未连接
    CONNECTING = 'connecting',       // 连接中
    CONNECTED = 'connected',         // 已连接
    RECONNECTING = 'reconnecting',   // 重连中
    ERROR = 'error'                  // 连接错误
}

/**
 * 常用的WebSocket消息类型定义命名空间
 */
namespace WebSocketMessageTypes {
    /**
     * 预检测相关消息
     */
    export interface PreTestMessage {
        deviceId?: string;
        status?: string;
        progress?: number;
        errorInfo?: string;
    }
    
    /**
     * 系数校准相关消息
     */
    export interface CoefficientMessage {
        deviceId: string;
        channel: number;
        voltage?: string;
        current?: string;
        calibrationResult?: boolean;
    }
    
    /**
     * 正式检测相关消息
     */
    export interface TestMessage {
        deviceId: string;
        testType: string;
        testResult?: 'success' | 'failed' | 'processing';
        testData?: any;
    }
    
    /**
     * 通用响应消息
     */
    export interface CommonResponse {
        success: boolean;
        message?: string;
        timestamp?: number;
    }
}

// ============================================================================
// 导出类型
// ============================================================================

export type { 
    WebSocketMessage, 
    CallbackFunction, 
    SocketConfig, 
    WebSocketMessageTypes
};

export { 
    ConnectionStatus
};

// ============================================================================
// 主要服务类
// ============================================================================

/**
 * WebSocket服务类
 * 单例模式实现，提供完整的WebSocket连接管理功能
 */
export default class SocketService {
    // ========================================================================
    // 静态属性和方法 (Static)
    // ========================================================================

    /**
     * 单例实例
     */
    private static instance: SocketService | null = null;
    
    /**
     * 获取单例实例
     * @returns SocketService实例
     */
    static get Instance(): SocketService {
        if (!this.instance) {
            this.instance = new SocketService();
        }
        return this.instance;
    }

    // ========================================================================
    // 实例属性 (Properties)
    // ========================================================================

    /**
     * WebSocket连接实例
     */
    private ws: WebSocket | null = null;
    
    /**
     * 消息回调函数映射表
     */
    private callBackMapping: Record<string, CallbackFunction<any>> = {};
    
    /**
     * 当前连接状态
     */
    private connectionStatus: ConnectionStatus = ConnectionStatus.DISCONNECTED;
    
    /**
     * 发送消息重试计数器
     */
    private sendRetryCount: number = 0;
    
    /**
     * 连接重试计数器
     */
    private connectRetryCount: number = 0;
    
    /**
     * 心跳Worker实例
     */
    private heartbeatWorker: Worker | null = null;
    
    /**
     * Worker脚本的Blob URL
     */
    private workerBlobUrl: string | null = null;
    
    /**
     * 最后一次收到心跳响应的时间戳
     */
    private lastResponseHeartTime: number = Date.now();
    
    /**
     * WebSocket连接配置
     */
    private config: SocketConfig = {
        // url: 'ws://127.0.0.1:7777/hello',
        url: 'ws://192.168.1.124:7777/hello',
        heartbeatInterval: 9000,        // 9秒心跳间隔
        reconnectDelay: 5000,           // 5秒重连延迟
        maxReconnectAttempts: 5,        // 最多重连5次
        timeout: 30000                  // 30秒超时
    };

    // ========================================================================
    // 构造函数 (Constructor)
    // ========================================================================

    /**
     * 私有构造函数，防止外部直接实例化
     */
    private constructor() {
        this.initializeProperties();
    }

    /**
     * 初始化属性
     */
    private initializeProperties(): void {
        this.lastResponseHeartTime = Date.now();
    }

    // ========================================================================
    // Getter属性 (Computed)
    // ========================================================================

    /**
     * 获取连接状态
     * @returns 是否已连接
     */
    get connected(): boolean {
        return this.connectionStatus === ConnectionStatus.CONNECTED;
    }

    // ========================================================================
    // 公共方法 (Public Methods)
    // ========================================================================

    /**
     * 配置WebSocket连接参数
     * @param config 部分配置对象
     */
    public configure(config: Partial<SocketConfig>): void {
        this.config = { ...this.config, ...config };
    }

    /**
     * 连接WebSocket服务器（同步方式，保持向后兼容）
     */
    public connect(): Promise<void> | void {
        // 检查浏览器支持
        if (!window.WebSocket) {
            console.log('您的浏览器不支持WebSocket');
            return;
        }

        // 防止重复连接
        if (this.connectionStatus === ConnectionStatus.CONNECTING || this.connected) {
            console.warn('WebSocket已连接或正在连接中');
            return;
        }

        this.connectionStatus = ConnectionStatus.CONNECTING;
        
        try {
            this.ws = new WebSocket(this.buildWebSocketUrl());
            this.setupEventHandlersLegacy();
        } catch (error) {
            this.connectionStatus = ConnectionStatus.ERROR;
            console.error('WebSocket连接失败:', error);
        }
    }

    /**
     * 异步连接WebSocket服务器
     * @returns Promise<void>
     */
    public connectAsync(): Promise<void> {
        return new Promise((resolve, reject) => {
            // 检查浏览器支持
            if (!window.WebSocket) {
                const error = '您的浏览器不支持WebSocket';
                console.error(error);
                reject(new Error(error));
                return;
            }

            // 防止重复连接
            if (this.connectionStatus === ConnectionStatus.CONNECTING || this.connected) {
                console.warn('WebSocket已连接或正在连接中');
                resolve();
                return;
            }

            this.connectionStatus = ConnectionStatus.CONNECTING;
            
            try {
                this.ws = new WebSocket(this.buildWebSocketUrl());
                this.setupEventHandlers(resolve, reject);
            } catch (error) {
                this.connectionStatus = ConnectionStatus.ERROR;
                reject(error);
            }
        });
    }

    /**
     * 注册消息回调函数（支持泛型）
     * @param messageType 消息类型
     * @param callback 回调函数
     */
    public registerCallBack<T = any>(messageType: string, callback: CallbackFunction<T>): void {
        if (!messageType || typeof callback !== 'function') {
            console.error('注册回调函数参数无效');
            return;
        }
        this.callBackMapping[messageType] = callback;
        console.log(`注册消息处理器: ${messageType}`);
    }

    /**
     * 注销消息回调函数
     * @param messageType 消息类型
     */
    public unRegisterCallBack(messageType: string): void {
        if (this.callBackMapping[messageType]) {
            delete this.callBackMapping[messageType];
            console.log(`注销消息处理器: ${messageType}`);
        }
    }

    /**
     * 发送数据到WebSocket服务器
     * @param data 要发送的数据
     * @returns Promise<void>
     */
    public send(data: any): Promise<void> {
        return new Promise((resolve, reject) => {
            if (!this.connected || !this.ws) {
                // 未连接时的重试机制
                if (this.sendRetryCount < 3) {
                    this.sendRetryCount++;
                    setTimeout(() => {
                        this.send(data).then(resolve).catch(reject);
                    }, this.sendRetryCount * 500);
                    return;
                } else {
                    reject(new Error('WebSocket未连接且重试失败'));
                    return;
                }
            }

            try {
                // 重置重试计数
                this.sendRetryCount = 0;
                
                // 尝试发送JSON数据，失败则发送原始数据
                const message = typeof data === 'string' ? data : JSON.stringify(data);
                this.ws.send(message);
                
                console.log('发送消息:', message);
                resolve();
            } catch (error) {
                console.error('发送消息失败:', error);
                reject(error);
            }
        });
    }

    /**
     * 关闭WebSocket连接
     */
    public closeWs(): void {
        console.log('正在关闭WebSocket连接...');
        
        // 清理心跳
        this.clearHeartbeat();
        
        // 关闭连接
        if (this.ws) {
            this.ws.close(1000, '主动关闭连接');
            this.ws = null;
        }
        
        // 更新状态
        this.connectionStatus = ConnectionStatus.DISCONNECTED;
        this.connectRetryCount = 0;
        this.sendRetryCount = 0;
        
        console.log('WebSocket连接已关闭');
    }

    /**
     * 获取当前连接状态
     * @returns 连接状态枚举值
     */
    public getConnectionStatus(): ConnectionStatus {
        return this.connectionStatus;
    }

    /**
     * 获取连接统计信息
     * @returns 连接统计对象
     */
    public getConnectionStats(): {
        status: ConnectionStatus;
        connectRetryCount: number;
        lastResponseHeartTime: number;
    } {
        return {
            status: this.connectionStatus,
            connectRetryCount: this.connectRetryCount,
            lastResponseHeartTime: this.lastResponseHeartTime
        };
    }


    // ========================================================================
    // 私有方法 (Private Methods)
    // ========================================================================

    /**
     * 构建完整的WebSocket URL
     * 自动从JWT token中获取loginName作为name参数
     * @returns 完整的WebSocket URL
     */
    private buildWebSocketUrl(): string {
        const { url } = this.config;
        
        // 直接从JWT token中获取loginName作为name参数
        const loginName = jwtUtil.getLoginName();
        
        if (loginName) {
            const separator = url.includes('?') ? '&' : '?';
            return `${url}${separator}name=${encodeURIComponent(loginName)}`;
        }
        
        // 如果无法获取loginName，返回原始URL并输出警告
        console.warn('无法从JWT token中获取loginName，WebSocket连接可能会失败');
        return url;
    }

    /**
     * 设置WebSocket事件处理器（异步版本）
     * @param resolve Promise resolve回调
     * @param reject Promise reject回调
     */
    private setupEventHandlers(resolve: () => void, reject: (error: Error) => void): void {
        if (!this.ws) return;
        
        // 连接成功事件
        this.ws.onopen = () => {
            ElMessage.success("WebSocket连接服务端成功");
            console.log('WebSocket连接成功');
            this.connectionStatus = ConnectionStatus.CONNECTED;
            this.connectRetryCount = 0;
            this.startHeartbeat();
            resolve();
        };

        // 连接关闭事件
        this.ws.onclose = (event: CloseEvent) => {
            console.log('WebSocket连接关闭', event.code, event.reason);
            this.connectionStatus = ConnectionStatus.DISCONNECTED;
            this.clearHeartbeat();
            
            // 非正常关闭且未超过最大重连次数，尝试重连
            if (event.code !== 1000 && this.connectRetryCount < this.config.maxReconnectAttempts!) {
                this.attemptReconnect();
            }
        };

        // 连接错误事件
        this.ws.onerror = (error: Event) => {
            console.error('WebSocket连接错误:', error);
            ElMessage.error("WebSocket连接异常");
            this.connectionStatus = ConnectionStatus.ERROR;
            reject(new Error('WebSocket连接失败'));
        };

        // 消息接收事件
        this.ws.onmessage = (event: MessageEvent) => {
            this.handleMessage(event);
        };
    }

    /**
     * 设置WebSocket事件处理器（兼容版本）
     */
    private setupEventHandlersLegacy(): void {
        if (!this.ws) return;
        
        // 连接成功事件
        this.ws.onopen = () => {
            ElMessage.success("webSocket连接服务端成功了");
            console.log('连接服务端成功了');
            this.connectionStatus = ConnectionStatus.CONNECTED;
            this.connectRetryCount = 0;
            this.startHeartbeat();
        };

        // 连接关闭事件
        this.ws.onclose = (event: CloseEvent) => {
            console.log('连接webSocket服务端关闭');
            this.connectionStatus = ConnectionStatus.DISCONNECTED;
            this.clearHeartbeat();
            
            // 保持原有的重连逻辑（被注释掉的）
            // this.connectRetryCount++;
            /* setTimeout(() => {
                this.connect();
            }, 500 * this.connectRetryCount);*/
        };

        // 连接错误事件
        this.ws.onerror = () => {
            ElMessage.error("webSocket连接异常！");
            this.connectionStatus = ConnectionStatus.ERROR;
        };

        // 消息接收事件
        this.ws.onmessage = (event: MessageEvent) => {
            this.handleMessage(event);
        };
    }

    /**
     * 处理接收到的消息
     * 支持心跳响应、JSON消息和普通文本消息
     * @param event WebSocket消息事件
     */
    private handleMessage(event: MessageEvent): void {
        // console.log('Received message:', event.data);
        
        // 心跳响应处理
        if (event.data === 'over') {
            console.log(`${new Date().toLocaleTimeString()} - 收到心跳响应`);
            this.lastResponseHeartTime = Date.now();
            return;
        }

        // 检查消息是否为空或无效
        if (!event.data || event.data.trim() === '') {
            console.warn('收到空消息，跳过处理');
            return;
        }

        // 业务消息处理
        try {
            // 检查是否为JSON格式
            if (typeof event.data === 'string' && (event.data.startsWith('{') || event.data.startsWith('['))) {
                const message: WebSocketMessage = JSON.parse(event.data);
                if (message?.type && this.callBackMapping[message.type]) {
                    this.callBackMapping[message.type](message);
                } else {
                    console.warn('未找到对应的消息处理器:', message.type);
                }
            } else {
                // 非JSON格式的消息，作为普通文本处理
                console.log('收到非JSON格式消息:', event.data);
                // 可以添加文本消息的处理逻辑
                if (this.callBackMapping['text']) {
                    this.callBackMapping['text']({ 
                        type: 'text', 
                        data: event.data 
                    });
                }
            }
            
        } catch (error) {
            console.error('消息解析失败:', event.data, error);
            console.error('消息类型:', typeof event.data);
            console.error('消息长度:', event.data?.length || 0);
        }
    }

    // ========================================================================
    // 重连机制相关方法
    // ========================================================================

    /**
     * 尝试重新连接WebSocket
     */
    private attemptReconnect(): void {
        if (this.connectionStatus === ConnectionStatus.RECONNECTING) {
            return;
        }

        this.connectionStatus = ConnectionStatus.RECONNECTING;
        this.connectRetryCount++;
        
        const delay = this.config.reconnectDelay! * this.connectRetryCount;
        
        console.log(`尝试第${this.connectRetryCount}次重连，${delay}ms后开始...`);
        
        setTimeout(() => {
            try {
                const result = this.connect();
                if (result instanceof Promise) {
                    result.catch((error: any) => {
                        console.error('重连失败:', error);
                    });
                }
            } catch (error: any) {
                console.error('重连失败:', error);
            }
        }, delay);
    }

    // ========================================================================
    // 心跳机制相关方法
    // ========================================================================

    /**
     * 启动心跳机制
     */
    private startHeartbeat(): void {
        this.lastResponseHeartTime = Date.now();
        this.createHeartbeatWorker();
    }

    /**
     * 创建心跳Worker
     * 使用Worker在独立线程中处理心跳定时器，避免主线程阻塞
     */
    private createHeartbeatWorker(): void {
        try {
            // 创建Worker脚本
            const workerScript = `
                setInterval(function() {
                    postMessage('heartbeat');
                }, ${this.config.heartbeatInterval});
            `;
            
            this.workerBlobUrl = window.URL.createObjectURL(
                new Blob([workerScript], { type: 'application/javascript' })
            );
            
            this.heartbeatWorker = new Worker(this.workerBlobUrl);
            
            // 心跳Worker消息处理
            this.heartbeatWorker.onmessage = (event: MessageEvent) => {
                this.handleHeartbeatTick();
            };
            
            // Worker错误处理
            this.heartbeatWorker.onerror = (error: ErrorEvent) => {
                console.error('心跳Worker错误:', error);
                this.clearHeartbeat();
            };
            
        } catch (error) {
            console.error('创建心跳Worker失败:', error);
        }
    }

    /**
     * 处理心跳定时器事件
     * 检查连接超时并发送心跳消息
     */
    private handleHeartbeatTick(): void {
        // 检查是否超时（距离上次收到心跳响应的时间）
        const timeSinceLastResponse = Date.now() - this.lastResponseHeartTime;
        
        if (timeSinceLastResponse > this.config.timeout!) {
            console.error(`WebSocket心跳超时: ${timeSinceLastResponse}ms > ${this.config.timeout}ms`);
            ElMessage.error("WebSocket连接超时，请检查网络连接！");
            this.clearHeartbeat();
            this.closeWs();
            return;
        }
        
        this.sendHeartbeat();
    }

    /**
     * 发送心跳消息到服务器
     */
    private sendHeartbeat(): void {
        if (this.connected && this.ws) {
            console.log(`${new Date().toLocaleTimeString()} - 发送心跳消息`);
            this.ws.send('alive');
        }
    }

    /**
     * 清理心跳机制
     * 终止Worker并清理相关资源
     */
    private clearHeartbeat(): void {
        if (this.heartbeatWorker) {
            this.heartbeatWorker.terminate();
            this.heartbeatWorker = null;
        }
        
        if (this.workerBlobUrl) {
            window.URL.revokeObjectURL(this.workerBlobUrl);
            this.workerBlobUrl = null;
        }
    }
}