/**
 * ============================================================================
 * AutoFill Handler Module (Modularized Version)
 * ============================================================================
 * 功能：
 *   1. 智能識別並填充支付表單 (信用卡、賬單地址)
 *   2. 模擬真實用戶輸入事件 (繞過 React/Vue/Angular 的狀態檢查)
 *   3. MutationObserver 實時監聽動態加載的表單
 *   4. 內置多國賬單地址生成庫 (AVS 繞過)
 *   5. 與其他模塊 (Card Generator) 聯動
 * 
 * 使用方式：
 *   const autofill = new AutoFillHandlerModule(config);
 *   autofill.init();
 * ============================================================================
 */

class AutoFillHandlerModule {
    constructor(config = {}) {
        this.config = {
            enabled: true,
            debug: false,
            fillCardData: true,
            fillBillingData: true,
            fillDelay: 500,           // 填充延遲 (毫秒)，模擬人類思考
            typeDelay: 10,            // 字符間隔延遲 (可選，用於更高級模擬)
            autoSubmit: false,        // 是否填充後自動提交
            targetCountry: 'US',      // 默認賬單國家
            
            // 字段選擇器映射 (支持 CSS 選擇器數組)
            selectors: {
                cardNumber: [
                    'input[name*="card"][name*="number"]',
                    'input[name="cardNumber"]',
                    'input[id*="cardNumber"]',
                    '.card-number input',
                    'input[autocomplete="cc-number"]',
                    'input[placeholder*="Card number"]'
                ],
                expDate: [
                    'input[name*="exp"]',
                    'input[id*="exp"]',
                    'input[autocomplete="cc-exp"]',
                    'input[placeholder*="MM / YY"]'
                ],
                cvc: [
                    'input[name*="cvc"]',
                    'input[name*="cvv"]',
                    'input[autocomplete="cc-csc"]',
                    'input[placeholder*="CVC"]'
                ],
                holderName: [
                    'input[name*="name"]',
                    'input[autocomplete="cc-name"]',
                    'input[id*="holder"]',
                    'input[placeholder*="Cardholder"]'
                ],
                address: ['input[name*="address"]', 'input[autocomplete="street-address"]', 'input[id*="address"]'],
                city: ['input[name*="city"]', 'input[autocomplete="address-level2"]'],
                state: ['input[name*="state"]', 'select[name*="state"]', 'input[autocomplete="address-level1"]'],
                zip: ['input[name*="zip"]', 'input[name*="postal"]', 'input[autocomplete="postal-code"]'],
                country: ['select[name*="country"]', 'select[id*="country"]', 'input[name*="country"]'],
                phone: ['input[name*="phone"]', 'input[type="tel"]']
            },
            
            // 外部數據源 (如果提供，將覆蓋內部庫)
            billingData: null,
            ...config
        };

        // 內部狀態
        this.observer = null;
        this.lastFilledTime = 0;
        this.cachedCard = null;

        // 內置地址庫 (簡化版，實際使用可擴展)
        this.billingDB = {
            'US': {
                name: 'James Smith',
                address: '450 West 33rd Street',
                city: 'New York',
                state: 'NY',
                zip: '10001',
                country: 'US',
                phone: '2125550199'
            },
            'GB': {
                name: 'Arthur Dent',
                address: '42 Islington High St',
                city: 'London',
                state: '',
                zip: 'N1 8EQ',
                country: 'GB',
                phone: '02079460123'
            },
            'CN': {
                name: 'Zhang Wei',
                address: 'No. 1 Fuxingmen Inner Street',
                city: 'Beijing',
                state: 'Beijing',
                zip: '100031',
                country: 'CN',
                phone: '13910998888'
            }
        };

        // 合併配置中的數據
        if (this.config.billingData) {
            Object.assign(this.billingDB, this.config.billingData);
        }

        // 綁定方法
        this.handleMutations = this.handleMutations.bind(this);
    }

    /**
     * 初始化模塊
     */
    init() {
        this.log('Initializing AutoFill Handler Module...');
        
        // 1. 啟動 DOM 監聽
        this.startObserver();

        // 2. 監聽卡號生成事件 (來自 GOG/Stripe 模塊)
        this.setupEventListeners();

        // 3. 檢查頁面上已有的表單
        if (document.readyState === 'complete' || document.readyState === 'interactive') {
            this.scanAndFill(document.body);
        } else {
            document.addEventListener('DOMContentLoaded', () => this.scanAndFill(document.body));
        }

        // 4. 暴露全局 API
        this.exposeGlobalAPI();

        this.log('Module initialized. Waiting for forms...');
    }

    /**
     * 銷毀模塊
     */
    destroy() {
        if (this.observer) {
            this.observer.disconnect();
            this.observer = null;
        }
        this.log('Module destroyed');
    }

    /**
     * ========================================================================
     * 事件監聽與聯動
     * ========================================================================
     */

    setupEventListeners() {
        // 監聽 GOG/Stripe 模塊的卡號生成事件
        const eventNames = ['GOG_CARD_GENERATED', 'STRIPE_CARD_GENERATED', 'CARD_GENERATED'];
        
        eventNames.forEach(evt => {
            document.addEventListener(evt, (e) => {
                this.log(`Received card data from ${evt}`, e.detail);
                if (e.detail && e.detail.card) {
                    this.setCardData(e.detail.card);
                }
            });
        });

        // 監聽 postMessage
        window.addEventListener('message', (event) => {
            if (event.data?.eventType === 'CARD_GENERATED') {
                this.log('Received card data from postMessage', event.data.card);
                this.setCardData(event.data.card);
            }
        });
    }

    setCardData(card) {
        this.cachedCard = card;
        // 收到新卡後立即重新掃描頁面
        this.scanAndFill(document.body);
    }

    /**
     * ========================================================================
     * Mutation Observer (DOM 監聽)
     * ========================================================================
     */

    startObserver() {
        if (this.observer) return;

        this.observer = new MutationObserver(this.handleMutations);
        this.observer.observe(document.body, {
            childList: true,
            subtree: true
        });
        
        this.log('DOM Observer started');
    }

    handleMutations(mutations) {
        let shouldScan = false;

        for (const mutation of mutations) {
            if (mutation.addedNodes.length > 0) {
                for (const node of mutation.addedNodes) {
                    if (node.nodeType === 1) { // 元素節點
                        // 簡單過濾：只關注包含 input/select/iframe 的節點
                        if (node.tagName === 'INPUT' || 
                            node.tagName === 'SELECT' || 
                            node.tagName === 'IFRAME' ||
                            node.querySelector('input, select, iframe')) {
                            shouldScan = true;
                            break;
                        }
                    }
                }
            }
            if (shouldScan) break;
        }

        if (shouldScan) {
            // 防抖動：不要頻繁掃描
            if (this._scanTimeout) clearTimeout(this._scanTimeout);
            this._scanTimeout = setTimeout(() => {
                this.scanAndFill(document.body);
            }, 200);
        }
    }

    /**
     * ========================================================================
     * 核心填充邏輯
     * ========================================================================
     */

    async scanAndFill(container) {
        if (!this.config.enabled) return;
        
        // 獲取卡數據：優先使用緩存的 (剛生成的)，其次嘗試從 Storage 讀取
        let cardData = this.cachedCard;
        if (!cardData) {
            cardData = this.loadCardFromStorage();
        }

        if (!cardData && this.config.fillCardData) {
            // 如果沒有卡數據，我們只能填充地址
            this.log('No card data available yet. Skipping card fields.');
        }

        // 獲取賬單數據
        const billingProfile = this.billingDB[this.config.targetCountry] || this.billingDB['US'];

        this.log('Scanning container for fields...');

        // 1. 填充信用卡字段
        if (this.config.fillCardData && cardData) {
            await this.fillField(container, this.config.selectors.cardNumber, cardData.number);
            
            // 日期處理：有的表單是 MM / YY 分開，有的是合併
            // 這裡簡單處理合併的情況，或者可以擴展檢測邏輯
            const expVal = `${cardData.month} / ${cardData.year.slice(-2)}`;
            await this.fillField(container, this.config.selectors.expDate, expVal);
            
            await this.fillField(container, this.config.selectors.cvc, cardData.cvc);
        }

        // 2. 填充賬單字段
        if (this.config.fillBillingData && billingProfile) {
            await this.fillField(container, this.config.selectors.holderName, billingProfile.name);
            await this.fillField(container, this.config.selectors.address, billingProfile.address);
            await this.fillField(container, this.config.selectors.city, billingProfile.city);
            await this.fillField(container, this.config.selectors.state, billingProfile.state);
            await this.fillField(container, this.config.selectors.zip, billingProfile.zip);
            await this.fillField(container, this.config.selectors.phone, billingProfile.phone);
            
            // 國家字段比較特殊，通常是 Select
            const countryEl = this.findElement(container, this.config.selectors.country);
            if (countryEl) {
                this.log('Found country field, attempting to set:', billingProfile.country);
                this.simulateSelect(countryEl, billingProfile.country);
            }
        }
    }

    /**
     * 查找並填充單個字段
     */
    async fillField(container, selectors, value) {
        if (!value) return;

        const element = this.findElement(container, selectors);
        if (element) {
            // 檢查是否已經填充過，避免覆蓋用戶手動輸入
            if (element.value && element.value === value) return;
            if (element.getAttribute('data-autofilled') === 'true') return;

            this.log(`Filling field [${element.name || element.id}] with value length: ${value.length}`);
            
            // 延遲模擬
            await this.sleep(this.config.fillDelay);
            
            this.simulateInput(element, value);
            element.setAttribute('data-autofilled', 'true');
            
            // 高亮顯示 (可選，便於調試)
            if (this.config.debug) {
                element.style.backgroundColor = '#e8f0fe';
                element.style.transition = 'background-color 0.5s';
            }
        }
    }

    /**
     * 輔助函數：根據選擇器列表查找元素
     */
    findElement(container, selectors) {
        for (const selector of selectors) {
            // 嘗試查找
            const el = container.querySelector(selector);
            // 確保元素可見且可編輯
            if (el && !el.disabled && el.offsetParent !== null) {
                return el;
            }
        }
        return null;
    }

    /**
     * ========================================================================
     * 輸入模擬 (核心黑魔法)
     * ========================================================================
     */

    /**
     * 模擬輸入事件序列
     * 這是繞過 React/Angular 狀態綁定的關鍵
     */
    simulateInput(element, value) {
        if (!element) return;

        // 1. 獲取並保存原始值屬性描述符
        const nativeInputValueSetter = Object.getOwnPropertyDescriptor(window.HTMLInputElement.prototype, "value").set;

        // 2. 聚焦
        element.focus();
        element.dispatchEvent(new Event('focus', { bubbles: true }));

        // 3. 設置值 (使用原生 Setter 繞過框架代理)
        nativeInputValueSetter.call(element, value);

        // 4. 觸發一系列事件
        const events = [
            new KeyboardEvent('keydown', { bubbles: true }),
            new KeyboardEvent('keypress', { bubbles: true }),
            new InputEvent('input', { bubbles: true, inputType: 'insertText', data: value }),
            new KeyboardEvent('keyup', { bubbles: true }),
            new Event('change', { bubbles: true })
        ];

        events.forEach(event => element.dispatchEvent(event));

        // 5. 失焦
        element.blur();
        element.dispatchEvent(new Event('blur', { bubbles: true }));
    }

    /**
     * 模擬下拉框選擇
     */
    simulateSelect(element, value) {
        if (!element) return;

        // 嘗試匹配選項 (Value 或 Text)
        let found = false;
        for (let i = 0; i < element.options.length; i++) {
            const option = element.options[i];
            if (option.value === value || option.text.includes(value)) {
                element.selectedIndex = i;
                found = true;
                break;
            }
        }

        if (found) {
            element.dispatchEvent(new Event('change', { bubbles: true }));
            element.dispatchEvent(new Event('input', { bubbles: true }));
        }
    }

    /**
     * ========================================================================
     * 工具方法
     * ========================================================================
     */

    loadCardFromStorage() {
        try {
            // 嘗試讀取 GOG 模塊的存儲
            let json = localStorage.getItem('gogBypasserLastCardJSON');
            if (json) return JSON.parse(json);

            // 嘗試讀取通用存儲
            json = localStorage.getItem('StripeBypasserLastCard');
            if (json) return JSON.parse(json);
        } catch (e) {
            // ignore
        }
        return null;
    }

    sleep(ms) {
        return new Promise(resolve => setTimeout(resolve, ms));
    }

    /**
     * 全局 API
     */
    exposeGlobalAPI() {
        window.autofillHandler = {
            module: this,
            fill: () => this.scanAndFill(document.body),
            setCard: (card) => this.setCardData(card),
            updateConfig: (cfg) => { Object.assign(this.config, cfg); },
            getBillingProfile: (country) => this.billingDB[country]
        };
    }

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

/**
 * ============================================================================
 * 自動初始化
 * ============================================================================
 */
window.AutoFillHandlerModule = AutoFillHandlerModule;

if (typeof AUTOFILL_AUTO_INIT !== 'undefined' && AUTOFILL_AUTO_INIT) {
    const instance = new AutoFillHandlerModule({
        debug: true
    });
    instance.init();
    window.__autofill = instance;
}