/**
 * ============================================================================
 * 3D Secure (3DS) Handler Module (Modularized Version)
 * ============================================================================
 * 功能：
 *   1. 攔截 Stripe 3DS 驗證相關的網絡請求
 *   2. 監控驗證流程狀態 (進行中/成功/失敗)
 *   3. 修改請求體以繞過指紋檢測
 *   4. 通過 postMessage 和自定義事件廣播結果
 *   5. 自動清理過期記錄防止內存泄漏
 * 
 * 使用方式：
 *   const handler = new ThreeDSecureHandlerModule(config);
 *   handler.init();
 * ============================================================================
 */

class ThreeDSecureHandlerModule {
    constructor(config = {}) {
        // 默認配置
        this.config = {
            enabled: true,                      // 是否啟用攔截
            debug: false,                       // 調試模式
            modifyPayload: false,               // 是否修改請求體
            cleanupInterval: 5000,              // 清理間隔 (ms)
            successTimeout: 30000,              // 成功記錄過期時間 (ms)
            maxCompletedRecords: 50,            // 最大完成記錄數
            targetDomains: [                    // 目標域名
                'stripe.com',
                'stripejs.com'
            ],
            targetKeywords: [                   // URL 關鍵詞
                '3d_secure',
                '3ds',
                'challenge',
                'authenticate'
            ],
            successIndicators: [                // 響應成功標識
                'challenge_completed',
                '3DS_COMPLETE',
                'authenticated',
                'success'
            ],
            failureIndicators: [                // 響應失敗標識
                'challenge_failed',
                '3DS_FAILED',
                'authentication_failed'
            ],
            ...config
        };

        // 運行時狀態
        this.inProgressRequests = new Set();    // 進行中的請求
        this.successfulRequests = new Map();    // 成功的請求 (url => timestamp)
        this.completedRequests = new Set();     // 已完成的請求
        this.cleanupIntervalId = null;

        // 原始方法引用
        this.originalFetch = null;
        this.originalXHROpen = null;
        this.originalXHRSend = null;

        // 綁定方法上下文
        this.handleFetch = this.handleFetch.bind(this);

        this.cleanup = this.cleanup.bind(this);
    }

    /**
     * 初始化模塊
     */
    init() {
        this.log('Initializing 3DS Handler Module...');

        // 1. 暴露狀態到全局 (供外部檢查)
        this.exposeGlobalState();

        // 2. Hook 網絡請求
        this.hookFetch();
        this.hookXHR();

        // 3. 啟動清理任務
        this.startCleanupTask();

        // 4. 註冊消息監聽
        this.setupMessageListener();

        this.log('Module initialized successfully');
    }

    /**
     * 銷毀模塊
     */
    destroy() {
        // 恢復原始方法
        if (this.originalFetch) {
            window.fetch = this.originalFetch;
        }
        if (this.originalXHROpen) {
            XMLHttpRequest.prototype.open = this.originalXHROpen;
        }
        if (this.originalXHRSend) {
            XMLHttpRequest.prototype.send = this.originalXHRSend;
        }

        // 清理定時器
        if (this.cleanupIntervalId) {
            clearInterval(this.cleanupIntervalId);
        }

        this.log('Module destroyed');
    }

    /**
     * 暴露狀態到全局
     */
    exposeGlobalState() {
        window.__3DSInProgress = this.inProgressRequests;
        window.__3DSSuccessful = this.successfulRequests;
        window.__3DSCompleted = this.completedRequests;
    }

    /**
     * ========================================================================
     * Fetch API Hook
     * ========================================================================
     */
    hookFetch() {
        if (this.originalFetch) return; // 防止重複 hook

        this.originalFetch = window.fetch;
        const self = this;

        window.fetch = async function(...args) {
            return await self.handleFetch(this, args, self.originalFetch);
        };

        this.log('Fetch API hooked');
    }

    async handleFetch(context, args, originalFetch) {
        const [url, options = {}] = args;
        const urlString = this.normalizeUrl(url);

        // 檢查是否為目標請求
        if (!this.isTargetRequest(urlString)) {
            return await originalFetch.apply(context, args);
        }

        this.log('Intercepted Fetch request:', urlString);
        this.inProgressRequests.add(urlString);

        // 修改請求體 (如果啟用)
        if (this.config.modifyPayload && options.body) {
            try {
                options.body = this.modifyRequestBody(options.body, urlString);
                this.log('Modified request body');
            } catch (e) {
                this.error('Failed to modify request body:', e);
            }
        }

        // 執行原始請求
        let response;
        try {
            response = await originalFetch.apply(context, [url, options]);
        } catch (err) {
            this.inProgressRequests.delete(urlString);
            this.error('Fetch request failed:', err);
            throw err;
        }

        // 處理響應
        await this.processResponse(response, urlString);

        return response;
    }

    /**
     * ========================================================================
     * XMLHttpRequest Hook
     * ========================================================================
     */
    hookXHR() {
        if (this.originalXHROpen) return;

        this.originalXHROpen = XMLHttpRequest.prototype.open;
        this.originalXHRSend = XMLHttpRequest.prototype.send;
        const self = this;

        // Hook open 方法以獲取 URL
        XMLHttpRequest.prototype.open = function(method, url, ...rest) {
            this._3dsUrl = self.normalizeUrl(url);
            this._3dsMethod = method;
            return self.originalXHROpen.apply(this, [method, url, ...rest]);
        };

        // Hook send 方法以處理請求和響應
        XMLHttpRequest.prototype.send = function(body) {
            const url = this._3dsUrl;

            if (!self.isTargetRequest(url)) {
                return self.originalXHRSend.apply(this, [body]);
            }

            self.log('Intercepted XHR request:', url);
            self.inProgressRequests.add(url);

            // 修改請求體
            if (self.config.modifyPayload && body) {
                try {
                    body = self.modifyRequestBody(body, url);
                    self.log('Modified XHR body');
                } catch (e) {
                    self.error('Failed to modify XHR body:', e);
                }
            }

            // 監聽響應
            const originalOnReadyStateChange = this.onreadystatechange;
            this.onreadystatechange = function() {
                if (this.readyState === 4) {
                    self.processXHRResponse(this, url);
                }
                if (originalOnReadyStateChange) {
                    originalOnReadyStateChange.apply(this, arguments);
                }
            };

            return self.originalXHRSend.apply(this, [body]);
        };

        this.log('XHR hooked');
    }

    /**
     * ========================================================================
     * 請求/響應處理
     * ========================================================================
     */

    /**
     * 標準化 URL
     */
    normalizeUrl(url) {
        try {
            if (typeof url === 'string') return url;
            if (url instanceof URL) return url.toString();
            if (url && url.url) return url.url;
            return String(url);
        } catch (e) {
            return '';
        }
    }

    /**
     * 判斷是否為目標請求
     */
    isTargetRequest(url) {
        if (!this.config.enabled || !url) return false;

        // 檢查域名
        const domainMatch = this.config.targetDomains.some(domain => 
            url.includes(domain)
        );

        // 檢查關鍵詞
        const keywordMatch = this.config.targetKeywords.some(keyword =>
            url.toLowerCase().includes(keyword.toLowerCase())
        );

        return domainMatch || keywordMatch;
    }

    /**
     * 修改請求體 (繞過指紋檢測)
     */
    modifyRequestBody(body, url) {
        // 這裡可以實現具體的修改邏輯
        // 例如：移除瀏覽器指紋參數、修改 User-Agent 相關字段等
        
        if (typeof body === 'string') {
            try {
                const json = JSON.parse(body);
                
                // 移除常見的指紋字段
                delete json.browser_fingerprint;
                delete json.device_fingerprint;
                delete json.canvas_fingerprint;
                
                // 強制某些安全參數
                if (json.challenge_type) {
                    json.challenge_type = 'frictionless'; // 嘗試跳過挑戰
                }

                return JSON.stringify(json);
            } catch (e) {
                // 不是 JSON，可能是 FormData 或其他格式
                return body;
            }
        }

        return body;
    }

    /**
     * 處理 Fetch 響應
     */
    async processResponse(response, url) {
        try {
            const clone = response.clone();
            const status = response.status;

            if (status === 200) {
                const text = await clone.text();
                const verificationStatus = this.analyzeResponseText(text);

                if (verificationStatus === 'success') {
                    this.handleSuccess(url, response.url);
                } else if (verificationStatus === 'failed') {
                    this.handleFailure(url);
                } else {
                    this.log('3DS request completed with unknown status');
                }
            }
        } catch (e) {
            this.error('Error processing response:', e);
        } finally {
            this.inProgressRequests.delete(url);
        }
    }

    /**
     * 處理 XHR 響應
     */
    processXHRResponse(xhr, url) {
        try {
            if (xhr.status === 200) {
                const text = xhr.responseText;
                const verificationStatus = this.analyzeResponseText(text);

                if (verificationStatus === 'success') {
                    this.handleSuccess(url, xhr.responseURL);
                } else if (verificationStatus === 'failed') {
                    this.handleFailure(url);
                }
            }
        } catch (e) {
            this.error('Error processing XHR response:', e);
        } finally {
            this.inProgressRequests.delete(url);
        }
    }

    /**
     * 分析響應文本判斷驗證狀態
     */
    analyzeResponseText(text) {
        if (!text) return 'unknown';

        const textLower = text.toLowerCase();

        // 檢查成功標識
        const isSuccess = this.config.successIndicators.some(indicator =>
            textLower.includes(indicator.toLowerCase())
        );

        if (isSuccess) return 'success';

        // 檢查失敗標識
        const isFailure = this.config.failureIndicators.some(indicator =>
            textLower.includes(indicator.toLowerCase())
        );

        if (isFailure) return 'failed';

        return 'unknown';
    }

    /**
     * 處理驗證成功
     */
    handleSuccess(requestUrl, responseUrl) {
        const timestamp = Date.now();
        const key = `${requestUrl}_${timestamp}`;

        this.successfulRequests.set(key, timestamp);
        this.completedRequests.add(requestUrl);

        this.log('✓ 3DS Verification Successful!', responseUrl);

        // 廣播成功消息
        this.broadcastEvent({
            type: 'STRIPE_BYPASSER_EVENT',
            eventType: '3DS_COMPLETE',
            status: 'success',
            url: responseUrl,
            requestUrl: requestUrl,
            timestamp: timestamp
        });

        // 觸發自定義 DOM 事件
        this.dispatchDOMEvent('3DS_COMPLETE', {
            status: 'success',
            url: responseUrl,
            requestUrl: requestUrl
        });
    }

    /**
     * 處理驗證失敗
     */
    handleFailure(url) {
        this.warn('✗ 3DS Verification Failed:', url);

        this.broadcastEvent({
            type: 'STRIPE_BYPASSER_EVENT',
            eventType: '3DS_FAILED',
            status: 'failed',
            url: url,
            timestamp: Date.now()
        });

        this.dispatchDOMEvent('3DS_FAILED', {
            status: 'failed',
            url: url
        });
    }

    /**
     * ========================================================================
     * 事件廣播
     * ========================================================================
     */

    /**
     * 通過 postMessage 廣播
     */
    broadcastEvent(data) {
        try {
            window.postMessage(data, '*');
            
            // 也嘗試向父窗口發送
            if (window.parent !== window) {
                window.parent.postMessage(data, '*');
            }
        } catch (e) {
            this.error('Failed to broadcast event:', e);
        }
    }

    /**
     * 觸發自定義 DOM 事件
     */
    dispatchDOMEvent(eventName, detail) {
        try {
            if (document) {
                const event = new CustomEvent(eventName, { detail });
                document.dispatchEvent(event);
            }
        } catch (e) {
            this.error('Failed to dispatch DOM event:', e);
        }
    }

    /**
     * 監聽來自外部的消息
     */
    setupMessageListener() {
        window.addEventListener('message', (event) => {
            if (event.data?.type === '3DS_HANDLER_UPDATE_CONFIG') {
                this.updateConfig(event.data.config);
            }

            if (event.data?.type === '3DS_HANDLER_RESET') {
                this.reset();
            }
        });
    }

    /**
     * ========================================================================
     * 清理與維護
     * ========================================================================
     */

    /**
     * 啟動清理任務
     */
    startCleanupTask() {
        if (this.cleanupIntervalId) return;

        this.cleanupIntervalId = setInterval(
            this.cleanup,
            this.config.cleanupInterval
        );

        this.log('Cleanup task started');
    }

    /**
     * 清理過期記錄
     */
    cleanup() {
        const now = Date.now();

        // 清理過期的成功記錄
        for (const [key, timestamp] of this.successfulRequests.entries()) {
            if (now - timestamp > this.config.successTimeout) {
                this.successfulRequests.delete(key);
            }
        }

        // 限制 completedRequests 大小
        if (this.completedRequests.size > this.config.maxCompletedRecords) {
            const entries = Array.from(this.completedRequests);
            const toRemove = entries.slice(
                0,
                entries.length - this.config.maxCompletedRecords
            );
            toRemove.forEach(item => this.completedRequests.delete(item));
        }

        if (this.config.debug) {
            this.log('Cleanup completed', {
                successful: this.successfulRequests.size,
                completed: this.completedRequests.size,
                inProgress: this.inProgressRequests.size
            });
        }
    }

    /**
     * 重置所有狀態
     */
    reset() {
        this.inProgressRequests.clear();
        this.successfulRequests.clear();
        this.completedRequests.clear();
        this.log('Module state reset');
    }

    /**
     * ========================================================================
     * 配置管理
     * ========================================================================
     */

    /**
     * 更新配置
     */
    updateConfig(newConfig) {
        Object.assign(this.config, newConfig);
        this.log('Config updated:', this.config);
    }

    /**
     * 獲取當前狀態
     */
    getStatus() {
        return {
            inProgress: Array.from(this.inProgressRequests),
            successful: Array.from(this.successfulRequests.keys()),
            completed: Array.from(this.completedRequests),
            config: this.config
        };
    }

    /**
     * ========================================================================
     * 日誌工具
     * ========================================================================
     */

    log(...args) {
        if (this.config.debug) {
            console.log('[3DS Handler]', ...args);
        }
    }

    warn(...args) {
        if (this.config.debug) {
            console.warn('[3DS Handler]', ...args);
        }
    }

    error(...args) {
        console.error('[3DS Handler]', ...args);
    }
}

/**
 * ============================================================================
 * 全局 API 暴露
 * ============================================================================
 */
window.ThreeDSecureHandlerModule = ThreeDSecureHandlerModule;

if (typeof THREE_DS_AUTO_INIT !== 'undefined' && THREE_DS_AUTO_INIT) {
    const instance = new ThreeDSecureHandlerModule({
        enabled: true,
        debug: true,
        modifyPayload: true
    });
    instance.init();
    window.__3dsHandler = instance;
}


// ============================================================================
// Extension Compatibility Wrapper
// ============================================================================
window.addEventListener('message', (event) => {
  if (event.source !== window) return;
  const message = event.data;

  if (message && message.type === 'INIT_MODULE' && message.moduleName === 'threeDSecure') {
    if (window.__threeDSecureInstance) return;
    try {
      const instance = new ThreeDSecureHandlerModule(message.config);
      instance.init();
      window.__threeDSecureInstance = instance;
      console.log('[Extension] 3D Secure Handler initialized');
    } catch (error) {
      console.error('[Extension] 3D Secure init failed:', error);
    }
  }

  if (message && message.type === 'DESTROY_MODULE' && message.instanceKey === '__threeDSecureInstance') {
    const instance = window.__threeDSecureInstance;
    if (instance && typeof instance.destroy === 'function') {
      instance.destroy();
      delete window.__threeDSecureInstance;
    }
  }
});