// ==UserScript==
// @name         北京执业药师-金航联平台 (Pro)
// @namespace    http://tampermonkey.net/
// @version      2.0.1
// @description  金航联平台自动化刷课脚本 v2.0 — 模块化重构，增强性能/可靠性/UI
// @author       Coren + fix
// @match        *://bjzyys.mtnet.com.cn/*
// @run-at       document-start
// @grant        GM_addStyle
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_xmlhttpRequest
// @grant        GM_notification
// @grant        GM_setClipboard
// @connect      api.deepseek.com
// @license CC BY-NC-SA 4.0
// ==/UserScript==

(function () {
    'use strict';

    // =========================================================================
    //  CONFIG
    // =========================================================================
    const CFG = {
        MODELS: { flash: 'deepseek-v4-flash', chat: 'deepseek-chat' },
        DEFAULT_MODEL: 'flash',
        API_URL: 'https://api.deepseek.com/chat/completions',
        API_PROMPT: '你是一个乐于助人的问题回答助手。聚焦于执业药师相关的内容，请根据用户提出的问题，提供准确、清晰的解答。注意回答时仅仅包括答案，不允许其他额外任何解释，输出为一行一道题目的答案，答案只能是题目序号:字母选项，不能包含文字内容。单选输出示例：1.A。多选输出示例：1.ABC。',
        KEEPALIVE_INTERVAL: 500,
        URL_CHECK_INTERVAL: 1500,
        MUTE_SYNC_INTERVAL: 2000,
        CHAPTER_CHECK_INTERVAL: 5000,
        API_TIMEOUT: 30000,
        API_RETRY: 3,
        API_RETRY_DELAY: 1000,
    };

    // =========================================================================
    //  STATE
    // =========================================================================
    const S = {
        get serviceActive() { return GM_getValue('mtnet_service_active', true); },
        set serviceActive(v) { GM_setValue('mtnet_service_active', v); },
        get muted() { return GM_getValue('mtnet_is_muted', true); },
        set muted(v) { GM_setValue('mtnet_is_muted', v); },
        get apiKey() { return GM_getValue('deepseek_api_key', ''); },
        set apiKey(v) { GM_setValue('deepseek_api_key', v); },
        get autoExam() { return GM_getValue('mtnet_auto_exam_mode', false); },
        set autoExam(v) { GM_setValue('mtnet_auto_exam_mode', v); },
        get model() { return GM_getValue('mtnet_model', CFG.DEFAULT_MODEL); },
        set model(v) { GM_setValue('mtnet_model', v); },
        get panelCollapsed() { return GM_getValue('mtnet_panel_collapsed', false); },
        set panelCollapsed(v) { GM_setValue('mtnet_panel_collapsed', v); },
        get examHistory() { return JSON.parse(GM_getValue('mtnet_exam_history', '[]')); },
        set examHistory(v) { GM_setValue('mtnet_exam_history', JSON.stringify(v)); },
        get logLevel() { return GM_getValue('mtnet_log_level', 1); },
        set logLevel(v) { GM_getValue('mtnet_log_level', v); },
        // runtime
        videoRef: null,
        keepAliveTimer: null,
        chapterTimer: null,
        muteTimer: null,
        urlCheckTimer: null,
        panelCreated: false,
        examPanelCreated: false,
    };

    // =========================================================================
    //  LOGGER
    // =========================================================================
    const LOG = {
        _fmt(level, tag, msg) { return `[${new Date().toLocaleTimeString()}] [${level}] [${tag}] ${msg}`; },
        debug(tag, msg, ...a) { if (S.logLevel >= 0) console.log(this._fmt('DBG', tag, msg), ...a); },
        info(tag, msg, ...a) { if (S.logLevel >= 1) console.log(this._fmt('INF', tag, msg), ...a); },
        warn(tag, msg, ...a) { if (S.logLevel >= 2) console.warn(this._fmt('WRN', tag, msg), ...a); },
        error(tag, msg, ...a) { if (S.logLevel >= 3) console.error(this._fmt('ERR', tag, msg), ...a); },
    };

    // =========================================================================
    //  UTILS
    // =========================================================================
    const $ = (sel, root) => (root || document).querySelector(sel);
    const $$ = (sel, root) => [...(root || document).querySelectorAll(sel)];
    const delay = (ms) => new Promise((r) => setTimeout(r, ms));
    const origin = () => window.location.origin;

    function findElementByText(selector, text) {
        return $$(selector).find((el) => el.innerText?.trim().includes(text.trim()));
    }

    function clickEl(el, desc) {
        if (!el || typeof el.click !== 'function') {
            LOG.warn('util', `点击失败: ${desc}`);
            return false;
        }
        LOG.debug('util', `点击: ${desc}`);
        el.click();
        return true;
    }

    function clickElEnhanced(el, desc) {
        if (!el) { LOG.warn('util', `增强点击失败: ${desc}`); return false; }
        LOG.debug('util', `增强点击: ${desc}`);
        const input = $('input[type="radio"], input[type="checkbox"]', el);
        if (input) { input.click(); return true; }
        el.click();
        try { el.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true })); } catch {}
        return true;
    }

    // =========================================================================
    //  ANTI-DETECTION  (must run at document-start)
    // =========================================================================
    const AntiDetect = {
        init() {
            this._hijackVisibility();
            this._hijackHasFocus();
            this._interceptEvents();
            this._interceptPause();
            this._setupFocusRestore();
            LOG.info('anti', '防检测机制已初始化');
        },
        _hijackVisibility() {
            const def = (obj, prop, val) => {
                try {
                    Object.defineProperty(obj, prop, { get: () => val, configurable: false });
                } catch {
                    try { Object.defineProperty(obj, prop, { get: () => val, configurable: true }); } catch (e) {
                        LOG.error('anti', `hijack ${prop} 失败`, e);
                    }
                }
            };
            def(document, 'visibilityState', 'visible');
            def(document, 'hidden', false);
        },
        _hijackHasFocus() {
            try { Document.prototype.hasFocus = () => true; } catch (e) {
                LOG.error('anti', 'hijack hasFocus 失败', e);
            }
        },
        _interceptEvents() {
            document.addEventListener('visibilitychange', (e) => e.stopImmediatePropagation(), true);
            window.addEventListener('blur', (e) => e.stopImmediatePropagation(), true);
        },
        _interceptPause() {
            document.addEventListener('pause', (e) => {
                if (!(e.target instanceof HTMLVideoElement)) return;
                e.stopImmediatePropagation();
                if (!e.target.ended) e.target.play().catch(() => {});
            }, true);
        },
        _setupFocusRestore() {
            window.addEventListener('focus', () => {
                for (const v of $$('video')) {
                    if (v.paused && !v.ended) v.play().catch(() => {});
                }
            });
        },
    };

    // =========================================================================
    //  VIDEO CONTROLLER
    // =========================================================================
    const VideoCtrl = {
        _cachedRef: null,

        start() {
            KeepAlive.start();
            MuteSync.start();
            this._observeDOM();
        },

        stop() {
            KeepAlive.stop();
            MuteSync.stop();
        },

        async find(timeout = 15000) {
            if (this._cachedRef && !this._cachedRef.isConnected) this._cachedRef = null;
            if (this._cachedRef) return this._cachedRef;

            const t0 = Date.now();
            while (Date.now() - t0 < timeout) {
                const v = $('video');
                if (v) { this._cachedRef = v; return v; }
                const iframe = $('iframe');
                if (iframe?.contentWindow) {
                    try {
                        const iv = iframe.contentWindow.document.querySelector('video');
                        if (iv) { this._cachedRef = iv; return iv; }
                    } catch {}
                }
                await delay(500);
            }
            return null;
        },

        _observeDOM() {
            const obs = new MutationObserver(() => { this._cachedRef = null; });
            obs.observe(document.body || document.documentElement, { childList: true, subtree: true });
        },
    };

    // =========================================================================
    //  KEEP-ALIVE
    // =========================================================================
    const KeepAlive = {
        start() {
            if (S.keepAliveTimer) return;
            S.keepAliveTimer = setInterval(() => {
                for (const v of $$('video')) {
                    if (v.paused && !v.ended && v.readyState >= 2) v.play().catch(() => {});
                }
            }, CFG.KEEPALIVE_INTERVAL);
        },
        stop() {
            if (S.keepAliveTimer) { clearInterval(S.keepAliveTimer); S.keepAliveTimer = null; }
        },
    };

    // =========================================================================
    //  MUTE SYNC
    // =========================================================================
    const MuteSync = {
        start() {
            this._tick();
        },
        stop() {
            if (S.muteTimer) { clearTimeout(S.muteTimer); S.muteTimer = null; }
        },
        async _tick() {
            if (!S.serviceActive || !window.location.href.includes('/video/')) {
                S.muteTimer = setTimeout(() => this._tick(), CFG.MUTE_SYNC_INTERVAL);
                return;
            }
            try {
                const v = await VideoCtrl.find();
                if (v && v.muted !== S.muted) v.muted = S.muted;
            } catch (e) { LOG.warn('mute', '同步异常', e); }
            S.muteTimer = setTimeout(() => this._tick(), CFG.MUTE_SYNC_INTERVAL);
        },
    };

    // =========================================================================
    //  API CLIENT
    // =========================================================================
    const Api = {
        async ask(questions, modelKey) {
            const model = CFG.MODELS[modelKey || S.model] || CFG.MODELS.flash;
            let lastErr;
            for (let i = 0; i < CFG.API_RETRY; i++) {
                try {
                    const result = await this._request(model, questions);
                    return result;
                } catch (e) {
                    lastErr = e;
                    LOG.warn('api', `请求失败 (${i + 1}/${CFG.API_RETRY}): ${e.message}`);
                    if (i < CFG.API_RETRY - 1) await delay(CFG.API_RETRY_DELAY * (i + 1));
                }
            }
            throw lastErr;
        },

        _request(model, content) {
            return new Promise((resolve, reject) => {
                const timer = setTimeout(() => reject(new Error('API 请求超时')), CFG.API_TIMEOUT);
                GM_xmlhttpRequest({
                    method: 'POST',
                    url: CFG.API_URL,
                    headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${S.apiKey}` },
                    data: JSON.stringify({
                        model,
                        messages: [
                            { role: 'system', content: CFG.API_PROMPT },
                            { role: 'user', content },
                        ],
                        stream: false,
                        thinking: { type: 'disabled' },
                    }),
                    onload(res) {
                        clearTimeout(timer);
                        if (res.status === 200) {
                            try {
                                const r = JSON.parse(res.responseText);
                                resolve(r.choices[0].message.content);
                            } catch (e) { reject(new Error('解析响应失败')); }
                        } else { reject(new Error(`API 状态码: ${res.status}`)); }
                    },
                    onerror(e) { clearTimeout(timer); reject(new Error('网络请求错误')); },
                });
            });
        },
    };

    // =========================================================================
    //  EXAM ENGINE
    // =========================================================================
    const ExamEngine = {
        extract() {
            const qs = $$('div[id^="q"]');
            if (!qs.length) { LOG.error('exam', '未找到题目容器'); return null; }
            let text = '';
            let n = 1;
            for (const q of qs) {
                const allText = q.innerText;
                const opts = $$('.el-radio__label, .el-checkbox__label', q);
                let end = allText.length;
                for (const o of opts) {
                    const idx = allText.indexOf(o.innerText);
                    if (idx !== -1 && idx < end) end = idx;
                }
                const stem = allText.substring(0, end).trim().replace(/^\d+\.?\s*/, '');
                if (!stem) continue;
                text += `${n}. ${stem}\n`;
                for (const o of opts) text += o.innerText + '\n';
                text += '\n';
                n++;
            }
            LOG.info('exam', `提取 ${n - 1} 道题`);
            return text || null;
        },

        parseAnswers(answerText) {
            const map = new Map();
            answerText.trim().split('\n').forEach((line) => {
                const m = line.match(/(\d+)\s*\.\s*([A-Z]+)/i);
                if (m) map.set(parseInt(m[1], 10), m[2].toUpperCase());
            });
            return map;
        },

        async fill(answers) {
            const map = typeof answers === 'string' ? this.parseAnswers(answers) : answers;
            const qs = $$('div[id^="q"]');
            for (let i = 0; i < qs.length; i++) {
                const q = qs[i];
                const num = i + 1;
                if (!map.has(num)) { LOG.warn('exam', `第 ${num} 题无答案`); continue; }
                const chars = map.get(num);
                LOG.debug('exam', `填写第 ${num} 题: ${chars}`);
                for (const ch of chars.split('')) {
                    const labels = $$('.el-radio, .el-checkbox', q);
                    let ok = false;
                    for (const lb of labels) {
                        const lbText = $('.el-radio__label, .el-checkbox__label', lb)?.innerText?.trim();
                        if (lbText?.startsWith(ch)) {
                            clickElEnhanced(lb, `Q${num} 选项 ${ch}`);
                            await delay(200);
                            ok = true;
                        }
                    }
                    if (!ok) LOG.warn('exam', `Q${num} 未找到选项 ${ch}`);
                }
            }
        },

        findSubmitBtn() {
            for (const kw of ['交卷', '提交试卷', '提交']) {
                const btn = findElementByText('span, button, a, div, .btn, .el-button', kw);
                if (btn) return btn;
            }
            return $('.nextClick, .nextBtn, .loginBtn, .btn-submit, .submit-btn, .el-button--primary, button[type="submit"]');
        },

        async confirmDialog() {
            for (let i = 0; i < 40; i++) {
                await delay(250);
                for (const sel of [
                    '.el-message-box__btns .el-button--primary',
                    '.el-dialog__footer .el-button--primary',
                    '.el-message-box__btns button',
                    '.el-dialog__footer button',
                ]) {
                    for (const btn of $$(sel)) {
                        const t = btn.innerText?.trim();
                        if (['确定', '确认', '确认交卷', '是', 'OK'].includes(t)) {
                            LOG.info('exam', `确认按钮: ${t}`);
                            btn.click();
                            return true;
                        }
                    }
                }
                for (const kw of ['确定', '确认', '确认交卷']) {
                    const btn = findElementByText('button, .el-button, .btn', kw);
                    if (btn?.closest('.el-message-box, .el-dialog, .modal, .popup, .el-message')) {
                        btn.click();
                        return true;
                    }
                }
            }
            LOG.warn('exam', '未找到确认对话框');
            return false;
        },

        saveHistory(text, answers) {
            const h = S.examHistory;
            h.push({ time: new Date().toISOString(), url: location.href, questions: text, answers });
            if (h.length > 50) h.splice(0, h.length - 50);
            S.examHistory = h;
        },
    };

    // =========================================================================
    //  NOTIFICATION
    // =========================================================================
    const Notify = {
        show(title, text, onclick) {
            try {
                GM_notification({ title, text, timeout: 5000, onclick });
            } catch {}
        },
    };

    // =========================================================================
    //  UI — CONTROL PANEL
    // =========================================================================
    const UI = {
        create() {
            if (S.panelCreated) return;
            S.panelCreated = true;
            this._injectStyles();
            const panel = this._buildPanel();
            document.body.appendChild(panel);
            requestAnimationFrame(() => {
                const w = panel.offsetWidth || 240;
                const h = panel.offsetHeight || 260;
                panel.style.left = Math.max(0, window.innerWidth - w - 20) + 'px';
                panel.style.top = Math.max(0, window.innerHeight - h - 20) + 'px';
            });
            this._bindEvents(panel);
            Draggable.init(panel, $('#control-panel-header', panel));
        },

        _injectStyles() {
            GM_addStyle(`
                #control-panel{position:fixed;width:240px;background:#fff;border:1px solid #e0e0e0;border-radius:10px;box-shadow:0 4px 20px rgba(0,0,0,.15);z-index:10000;font-family:'Microsoft YaHei',sans-serif;transition:height .25s,box-shadow .25s;overflow:hidden}
                #control-panel:hover{box-shadow:0 6px 28px rgba(0,0,0,.2)}
                #control-panel-header{padding:8px 12px;background:linear-gradient(135deg,#007bff,#0056b3);color:#fff;cursor:move;user-select:none;font-size:13px;display:flex;align-items:center;justify-content:space-between}
                #control-panel-header .panel-title{font-weight:600;letter-spacing:.5px}
                .panel-header-btns{display:flex;gap:4px}
                .panel-header-btns button{background:rgba(255,255,255,.2);border:none;color:#fff;width:24px;height:24px;border-radius:4px;cursor:pointer;font-size:14px;line-height:24px;text-align:center;padding:0;transition:background .2s}
                .panel-header-btns button:hover{background:rgba(255,255,255,.35)}
                #control-panel-content{padding:12px;display:flex;flex-direction:column;gap:8px;transition:max-height .25s,opacity .2s,padding .25s;overflow:hidden}
                #control-panel-content.collapsed{max-height:0!important;padding:0 12px!important;opacity:0;pointer-events:none}
                .panel-btn{padding:7px 14px;font-size:13px;color:#fff;border:none;border-radius:6px;cursor:pointer;transition:all .2s;width:100%;box-sizing:border-box;font-weight:500}
                .panel-btn:hover{filter:brightness(1.1);transform:translateY(-1px)}
                .panel-btn:active{transform:translateY(0)}
                .service-btn-active{background:linear-gradient(135deg,#28a745,#1e7e34)}
                .service-btn-paused{background:linear-gradient(135deg,#dc3545,#b02a37)}
                .mute-btn-on{background:linear-gradient(135deg,#ffc107,#e0a800);color:#333}
                .mute-btn-off{background:linear-gradient(135deg,#6c757d,#5a6268)}
                .panel-divider{width:100%;height:1px;background:#eee;margin:2px 0}
                .setting-row{display:flex;flex-direction:column;width:100%;gap:4px}
                .setting-row>label{font-size:12px;font-weight:600;color:#666}
                #api-key-input{width:100%;padding:6px 8px;border-radius:6px;border:1px solid #ddd;box-sizing:border-box;font-size:12px;transition:border-color .2s}
                #api-key-input:focus{border-color:#007bff;outline:none;box-shadow:0 0 0 2px rgba(0,123,255,.15)}
                .model-select{width:100%;padding:5px 8px;border-radius:6px;border:1px solid #ddd;box-sizing:border-box;font-size:12px}
                .config-btns{display:flex;gap:4px}
                .config-btns button{flex:1;padding:5px;font-size:11px;border:1px solid #ddd;border-radius:4px;cursor:pointer;background:#f8f9fa}
                .config-btns button:hover{background:#e9ecef}
                .log-level-row{display:flex;align-items:center;gap:6px}
                .log-level-row label{font-size:11px;color:#999}
                .log-level-row select{font-size:11px;padding:2px 4px;border-radius:4px;border:1px solid #ddd}
            `);
        },

        _buildPanel() {
            const collapsed = S.panelCollapsed;
            const div = document.createElement('div');
            div.id = 'control-panel';
            div.innerHTML = `
                <div id="control-panel-header">
                    <span class="panel-title">⚡ 刷课助手 v2.0</span>
                    <div class="panel-header-btns">
                        <button id="minimize-btn" title="最小化">—</button>
                        <button id="collapse-btn">${collapsed ? '▸' : '▾'}</button>
                    </div>
                </div>
                <div id="control-panel-content" class="${collapsed ? 'collapsed' : ''}">
                    <div class="setting-row"><label>总开关</label><button id="service-toggle-btn" class="panel-btn"></button></div>
                    <div class="panel-divider"></div>
                    <div class="setting-row"><label>静音设置</label><button id="mute-toggle-btn" class="panel-btn"></button></div>
                    <div class="panel-divider"></div>
                    <div class="setting-row"><label>DeepSeek API Key</label><input type="password" id="api-key-input" placeholder="输入API Key"></div>
                    <div class="setting-row"><label>AI 模型</label><select id="model-select" class="model-select"><option value="flash">DeepSeek v4 Flash</option><option value="chat">DeepSeek Chat</option></select></div>
                    <div class="panel-divider"></div>
                    <div class="setting-row"><label>配置管理</label><div class="config-btns"><button id="export-config-btn">导出</button><button id="import-config-btn">导入</button><button id="view-history-btn">答题历史</button></div></div>
                    <div class="panel-divider"></div>
                    <div class="setting-row log-level-row"><label>日志级别</label><select id="log-level-select"><option value="0">Debug</option><option value="1">Info</option><option value="2">Warn</option><option value="3">Error</option></select></div>
                </div>
            `;
            return div;
        },

        _bindEvents(panel) {
            const $id = (id) => panel.querySelector(`#${id}`);

            // API key (不通过 innerHTML，防 XSS)
            const keyInput = $id('api-key-input');
            keyInput.value = S.apiKey;
            keyInput.addEventListener('change', () => { S.apiKey = keyInput.value.trim(); });

            // model
            const modelSel = $id('model-select');
            modelSel.value = S.model;
            modelSel.addEventListener('change', () => { S.model = modelSel.value; });

            // log level
            const logSel = $id('log-level-select');
            logSel.value = String(S.logLevel);
            logSel.addEventListener('change', () => { S.logLevel = parseInt(logSel.value); });

            // collapse
            const content = $id('control-panel-content');
            const collapseBtn = $id('collapse-btn');
            collapseBtn.addEventListener('click', () => {
                const c = content.classList.toggle('collapsed');
                collapseBtn.textContent = c ? '▸' : '▾';
                S.panelCollapsed = c;
            });

            // minimize (收起为小图标)
            $id('minimize-btn').addEventListener('click', () => {
                panel.style.display = 'none';
                const badge = document.createElement('div');
                badge.id = 'control-panel-badge';
                badge.textContent = '⚡';
                badge.style.cssText = 'position:fixed;bottom:20px;right:20px;width:40px;height:40px;background:linear-gradient(135deg,#007bff,#0056b3);color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;cursor:pointer;z-index:10000;font-size:18px;box-shadow:0 2px 10px rgba(0,0,0,.3)';
                badge.addEventListener('click', () => { badge.remove(); panel.style.display = ''; });
                document.body.appendChild(badge);
            });

            // service toggle
            const svcBtn = $id('service-toggle-btn');
            const updateSvc = (a) => {
                svcBtn.textContent = a ? '● 运行中' : '● 已暂停';
                svcBtn.className = 'panel-btn ' + (a ? 'service-btn-active' : 'service-btn-paused');
            };
            updateSvc(S.serviceActive);
            svcBtn.addEventListener('click', () => { S.serviceActive = !S.serviceActive; location.reload(); });

            // mute toggle
            const muteBtn = $id('mute-toggle-btn');
            const updateMute = (m) => {
                muteBtn.textContent = m ? '🔇 静音' : '🔊 有声';
                muteBtn.className = 'panel-btn ' + (m ? 'mute-btn-on' : 'mute-btn-off');
            };
            updateMute(S.muted);
            muteBtn.addEventListener('click', async () => {
                S.muted = !S.muted;
                updateMute(S.muted);
                const v = await VideoCtrl.find();
                if (v) v.muted = S.muted;
            });

            // export (不导出 apiKey，防止泄露)
            $id('export-config-btn').addEventListener('click', () => {
                const cfg = {
                    model: S.model, muted: S.muted,
                    autoExam: S.autoExam, logLevel: S.logLevel, examHistory: S.examHistory,
                };
                const blob = new Blob([JSON.stringify(cfg, null, 2)], { type: 'application/json' });
                const a = document.createElement('a');
                a.href = URL.createObjectURL(blob);
                a.download = `mtnet-config-${new Date().toISOString().slice(0, 10)}.json`;
                a.click();
                URL.revokeObjectURL(a.href);
                Notify.show('导出成功', '配置已导出（API Key 未包含）');
            });

            // import (导入配置，apiKey 字段会被忽略，需手动输入)
            $id('import-config-btn').addEventListener('click', () => {
                const input = document.createElement('input');
                input.type = 'file';
                input.accept = '.json';
                input.addEventListener('change', (e) => {
                    const file = e.target.files[0];
                    if (!file) return;
                    const reader = new FileReader();
                    reader.onload = () => {
                        try {
                            const cfg = JSON.parse(reader.result);
                            if (cfg.apiKey) {
                                Notify.show('提示', '导入文件包含 API Key，出于安全考虑已忽略，请手动输入');
                            }
                            if (cfg.model) S.model = cfg.model;
                            if (cfg.muted !== undefined) S.muted = cfg.muted;
                            if (cfg.autoExam !== undefined) S.autoExam = cfg.autoExam;
                            if (cfg.logLevel !== undefined) S.logLevel = cfg.logLevel;
                            if (cfg.examHistory) S.examHistory = cfg.examHistory;
                            location.reload();
                        } catch { Notify.show('导入失败', '文件格式错误'); }
                    };
                    reader.readAsText(file);
                });
                input.click();
            });

            // history
            $id('view-history-btn').addEventListener('click', () => {
                const h = S.examHistory;
                if (!h.length) { Notify.show('答题历史', '暂无记录'); return; }
                const text = h.map((e, i) => `#${i + 1} ${e.time}\n${e.answers || '(无答案)'}`).join('\n\n');
                GM_setClipboard(text);
                Notify.show('已复制', `${h.length} 条历史已复制到剪贴板`);
            });
        },
    };

    // =========================================================================
    //  UI — EXAM PANEL
    // =========================================================================
    const ExamUI = {
        create() {
            if (S.examPanelCreated) return;
            S.examPanelCreated = true;
            this._injectStyles();
            const panel = this._build();
            document.body.appendChild(panel);
            this._bind(panel);
            Draggable.init(panel, $('#exam-helper-header', panel));
        },

        destroy() {
            const p = $('#exam-helper-panel');
            if (p) p.remove();
            S.examPanelCreated = false;
        },

        _injectStyles() {
            GM_addStyle(`
                #exam-helper-panel{position:fixed;top:20px;left:20px;width:450px;background:#f9f9f9;border:1px solid #007bff;border-radius:8px;box-shadow:0 4px 12px rgba(0,0,0,.2);z-index:10001;font-family:'Microsoft YaHei',sans-serif;display:flex;flex-direction:column;max-height:90vh}
                #exam-helper-header{padding:10px 15px;background-color:#007bff;color:#fff;cursor:move;border-top-left-radius:7px;border-top-right-radius:7px;font-size:16px;flex-shrink:0;display:flex;justify-content:space-between;align-items:center}
                #exam-helper-content{padding:15px;display:flex;flex-direction:column;gap:15px;overflow-y:auto}
                #exam-action-btn{color:#fff;padding:10px;border:none;border-radius:5px;font-size:16px;cursor:pointer;transition:background-color .3s}
                #exam-action-btn:disabled{background-color:#ccc;cursor:not-allowed}
                #exam-status{margin-top:5px;padding:10px;background-color:#e9ecef;border-radius:5px;text-align:center;font-size:14px;color:#495057;min-height:20px}
                .auto-mode-switch{display:flex;align-items:center;gap:8px;background:#e9ecef;padding:8px;border-radius:5px}
                .display-area{border:1px solid #ddd;background:#fff;padding:10px;border-radius:5px;max-height:200px;overflow-y:auto}
                .display-area h4{margin:0 0 10px 0;font-size:14px;border-bottom:1px solid #eee;padding-bottom:5px}
                .display-area pre{white-space:pre-wrap;word-wrap:break-word;font-size:12px;margin:0}
                #manual-ask-container{display:flex;flex-direction:column;gap:10px}
                #manual-question-input{width:100%;min-height:60px;padding:8px;border-radius:4px;border:1px solid #ccc;box-sizing:border-box}
                #manual-ask-btn{background-color:#5a6268;color:#fff;padding:8px;border:none;border-radius:5px;cursor:pointer}
                .exam-progress{width:100%;height:6px;background:#e9ecef;border-radius:3px;overflow:hidden}
                .exam-progress-bar{height:100%;background:linear-gradient(90deg,#28a745,#20c997);transition:width .3s;width:0%}
            `);
        },

        _build() {
            const div = document.createElement('div');
            div.id = 'exam-helper-panel';
            div.innerHTML = `
                <div id="exam-helper-header">
                    <span>AI 答题助手 v4.0</span>
                    <button id="exam-minimize-btn" style="background:rgba(255,255,255,.2);border:none;color:#fff;width:24px;height:24px;border-radius:4px;cursor:pointer;font-size:14px">—</button>
                </div>
                <div id="exam-helper-content">
                    <div class="auto-mode-switch"><input type="checkbox" id="auto-mode-checkbox"><label for="auto-mode-checkbox">自动答题模式</label></div>
                    <div class="exam-progress"><div id="exam-progress-bar" class="exam-progress-bar"></div></div>
                    <button id="exam-action-btn">开始自动答题</button>
                    <div id="exam-status">请先在主面板输入 API Key。</div>
                    <div id="qa-display-container" style="display:flex;gap:10px">
                        <div id="question-display" class="display-area" style="flex:1"><h4>提取的题目:</h4><pre></pre></div>
                        <div id="answer-display" class="display-area" style="flex:1"><h4>AI 回答:</h4><pre></pre></div>
                    </div>
                    <div id="manual-ask-container">
                        <h4>手动提问区</h4>
                        <textarea id="manual-question-input" placeholder="输入单个问题向AI提问..."></textarea>
                        <button id="manual-ask-btn">手动提问</button>
                        <div id="manual-answer-display" class="display-area" style="display:none"><h4>结果:</h4><pre></pre></div>
                    </div>
                </div>
            `;
            return div;
        },

        _bind(panel) {
            const $id = (id) => panel.querySelector(`#${id}`);
            const actionBtn = $id('exam-action-btn');
            const status = $id('exam-status');
            const autoCheck = $id('auto-mode-checkbox');
            const qPre = $id('question-display').querySelector('pre');
            const aPre = $id('answer-display').querySelector('pre');
            const pBar = $id('exam-progress-bar');
            const manualInput = $id('manual-question-input');
            const manualBtn = $id('manual-ask-btn');
            const manualDiv = $id('manual-answer-display');
            const manualPre = manualDiv.querySelector('pre');

            autoCheck.checked = S.autoExam;
            autoCheck.addEventListener('change', () => { S.autoExam = autoCheck.checked; status.textContent = `自动模式${S.autoExam ? '开启' : '关闭'}`; });

            const setProgress = (pct) => { pBar.style.width = pct + '%'; };
            const setBtn = (text, color, disabled) => { actionBtn.textContent = text; actionBtn.style.backgroundColor = color; actionBtn.disabled = disabled; };

            setBtn('开始自动答题', '#28a745', false);

            // minimize
            $id('exam-minimize-btn').addEventListener('click', () => {
                panel.style.display = 'none';
                const b = document.createElement('div');
                b.id = 'exam-badge';
                b.textContent = '📝';
                b.style.cssText = 'position:fixed;top:20px;right:20px;width:40px;height:40px;background:#007bff;color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;cursor:pointer;z-index:10001;font-size:18px;box-shadow:0 2px 10px rgba(0,0,0,.3)';
                b.addEventListener('click', () => { b.remove(); panel.style.display = ''; });
                document.body.appendChild(b);
            });

            // manual ask
            manualBtn.addEventListener('click', async () => {
                const q = manualInput.value.trim();
                if (!q) { alert('请输入问题！'); return; }
                if (!S.apiKey) { alert('请输入 API Key！'); return; }
                manualBtn.disabled = true;
                manualBtn.textContent = '思考中...';
                manualDiv.style.display = 'block';
                manualPre.textContent = '...';
                try {
                    manualPre.textContent = await Api.ask(q);
                } catch (e) {
                    manualPre.textContent = `失败: ${e.message}`;
                } finally {
                    manualBtn.disabled = false;
                    manualBtn.textContent = '手动提问';
                }
            });

            // auto run
            const runAuto = async () => {
                try {
                    setBtn('提取题目...', '#ffc107', true);
                    setProgress(10);
                    status.textContent = '正在提取题目...';
                    const text = ExamEngine.extract();
                    if (!text) throw new Error('未提取到题目');
                    qPre.textContent = text;

                    setBtn('请求 AI...', '#ffc107', true);
                    setProgress(30);
                    status.textContent = '正在请求 AI...';
                    const answers = await Api.ask(text);
                    if (!answers) throw new Error('AI 未返回答案');
                    aPre.textContent = answers;

                    setBtn('填写答案...', '#ffc107', true);
                    setProgress(60);
                    status.textContent = '正在填写答案...';
                    await ExamEngine.fill(answers);

                    setProgress(85);
                    status.textContent = '即将交卷...';
                    await delay(1500);
                    const btn = ExamEngine.findSubmitBtn();
                    if (!btn) throw new Error('未找到交卷按钮');
                    clickElEnhanced(btn, '交卷');
                    status.textContent = '等待确认...';
                    await ExamEngine.confirmDialog();

                    ExamEngine.saveHistory(text, answers);
                    setProgress(100);
                    status.textContent = '已交卷！';
                    Notify.show('考试完成', '已自动交卷');
                    await delay(3000);
                    location.href = `${origin()}/index`;
                } catch (e) {
                    LOG.error('exam', '自动模式错误', e);
                    status.textContent = `错误: ${e.message}`;
                    status.style.color = 'red';
                    setBtn('重新开始', '#28a745', false);
                    setProgress(0);
                }
            };

            // manual step-by-step
            let step = 'init';
            actionBtn.addEventListener('click', async () => {
                if (!S.apiKey) { status.textContent = '请先输入 API Key'; status.style.color = 'red'; return; }
                if (autoCheck.checked) { runAuto(); return; }

                try {
                    if (step === 'init') {
                        setBtn('提取中...', '#ffc107', true);
                        status.textContent = '提取题目并请求 AI...';
                        const text = ExamEngine.extract();
                        if (!text) throw new Error('未提取到题目');
                        qPre.textContent = text;
                        const answers = await Api.ask(text);
                        if (!answers) throw new Error('AI 未返回答案');
                        aPre.textContent = answers;
                        step = 'fill';
                        setBtn('填写答案', '#17a2b8', false);
                        status.textContent = 'AI 分析完成，点击填写';
                        status.style.color = '#007bff';
                    } else if (step === 'fill') {
                        setBtn('填写中...', '#ffc107', true);
                        status.textContent = '正在填写...';
                        await ExamEngine.fill(aPre.textContent);
                        step = 'submit';
                        setBtn('确认交卷', '#dc3545', false);
                        status.textContent = '已填写，点击交卷';
                        status.style.color = 'green';
                    } else if (step === 'submit') {
                        setBtn('交卷中...', '#6c757d', true);
                        const btn = ExamEngine.findSubmitBtn();
                        if (!btn) throw new Error('未找到交卷按钮');
                        clickElEnhanced(btn, '交卷');
                        status.textContent = '已交卷';
                        await delay(3000);
                        location.href = `${origin()}/index`;
                    }
                } catch (e) {
                    LOG.error('exam', '手动模式错误', e);
                    status.textContent = `错误: ${e.message}`;
                    status.style.color = 'red';
                    step = 'init';
                    setBtn('重新开始', '#28a745', false);
                }
            });
        },
    };

    // =========================================================================
    //  DRAGGABLE
    // =========================================================================
    const Draggable = {
        init(el, handle) {
            let dragging = false, ox, oy;
            handle.addEventListener('mousedown', (e) => {
                dragging = true;
                ox = e.clientX - el.getBoundingClientRect().left;
                oy = e.clientY - el.getBoundingClientRect().top;
                handle.style.cursor = 'grabbing';
            });
            document.addEventListener('mousemove', (e) => {
                if (!dragging) return;
                let x = e.clientX - ox;
                let y = e.clientY - oy;
                x = Math.max(0, Math.min(x, window.innerWidth - el.offsetWidth));
                y = Math.max(0, Math.min(y, window.innerHeight - el.offsetHeight));
                el.style.left = x + 'px';
                el.style.top = y + 'px';
            });
            document.addEventListener('mouseup', () => { dragging = false; handle.style.cursor = 'move'; });
        },
    };

    // =========================================================================
    //  PAGE HANDLERS
    // =========================================================================
    const Pages = {
        courseList() {
            LOG.info('page', '课程列表');
            try {
                const target = GM_getValue('mtnet_target_task', 'specialized_video');
                const isExam = target.includes('exam');
                const courseType = target.includes('specialized') ? '专业科目' : '公需科目';
                const filter = isExam ? '待考试' : '未完成';
                const btnSel = isExam ? '.indexTextBtn.onlineTest' : '.indexTextBtn';
                const btnText = isExam ? '在线考试' : '进入学习';

                const tab = findElementByText('span.gxkn', courseType);
                if (tab && !tab.classList.contains('active')) { clickEl(tab, `${courseType} 标签`); setTimeout(() => {}, 2000); }
                const flt = findElementByText('a.screenItem', filter);
                if (flt && !flt.classList.contains('active')) { clickEl(flt, `${filter} 筛选`); setTimeout(() => {}, 2000); }

                for (const course of $$('.indexCourseListSLi')) {
                    const btn = $(btnSel, course);
                    if (btn?.innerText?.trim() === btnText) {
                        clickEl(btn, btnText);
                        return;
                    }
                }
                LOG.info('page', '无可操作课程');
            } catch (e) { LOG.error('page', '课程列表处理异常', e); }
        },

        video() {
            LOG.info('page', '视频页面');
            VideoCtrl.start();
            if (S.chapterTimer) clearInterval(S.chapterTimer);
            S.chapterTimer = setInterval(() => {
                if (!location.href.includes('/video/')) { Pages._leaveVideo(); return; }
                const prog = $('.courseProgress .gkjd span[style*="color: rgb(255, 148, 102)"]');
                if (prog?.innerText?.trim().includes('100')) {
                    Pages._leaveVideo();
                    location.href = `${origin()}/index`;
                    return;
                }
                const chapters = $$('.detailRightC .chapterList li');
                const next = chapters.find((ch) => !$('span.chapterPro.floatR.currProgress', ch)?.innerText?.trim().includes('100'));
                if (next && !next.classList.contains('active')) {
                    clickEl($('a', next), '下一章节');
                } else if (!next) {
                    Pages._leaveVideo();
                    location.href = `${origin()}/index`;
                }
            }, CFG.CHAPTER_CHECK_INTERVAL);
        },

        exam() {
            LOG.info('page', '考试页面');
            VideoCtrl.stop();
            ExamUI.destroy();
            ExamUI.create();
        },

        _leaveVideo() {
            if (S.chapterTimer) { clearInterval(S.chapterTimer); S.chapterTimer = null; }
            VideoCtrl.stop();
        },
    };

    // =========================================================================
    //  KEYBOARD SHORTCUTS
    // =========================================================================
    const Shortcuts = {
        init() {
            document.addEventListener('keydown', (e) => {
                if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA' || e.target.tagName === 'SELECT') return;
                // Ctrl+Shift+S: 暂停/恢复
                if (e.ctrlKey && e.shiftKey && e.key === 'S') {
                    e.preventDefault();
                    S.serviceActive = !S.serviceActive;
                    location.reload();
                }
                // Ctrl+Shift+M: 静音切换
                if (e.ctrlKey && e.shiftKey && e.key === 'M') {
                    e.preventDefault();
                    S.muted = !S.muted;
                    Notify.show('静音切换', S.muted ? '已静音' : '已开启声音');
                }
                // Ctrl+Shift+H: 显示/隐藏面板
                if (e.ctrlKey && e.shiftKey && e.key === 'H') {
                    e.preventDefault();
                    const p = $('#control-panel');
                    if (p) p.style.display = p.style.display === 'none' ? '' : 'none';
                }
            });
        },
    };

    // =========================================================================
    //  ROUTER & INIT
    // =========================================================================
    const Router = {
        _lastUrl: '',

        run() {
            if (!S.serviceActive) { LOG.info('router', '服务已暂停'); return; }
            if (S.chapterTimer) { clearInterval(S.chapterTimer); S.chapterTimer = null; }
            const url = location.href;
            LOG.info('router', `URL: ${url}`);
            if (url.includes('/user/courses')) Pages.courseList();
            else if (url.includes('/video/')) Pages.video();
            else if (url.includes('/examination/')) Pages.exam();
            else { LOG.info('router', '未匹配页面'); VideoCtrl.stop(); }
        },

        start() {
            this.run();
            if (S.urlCheckTimer) clearInterval(S.urlCheckTimer);
            S.urlCheckTimer = setInterval(() => {
                if (location.href !== this._lastUrl) {
                    this._lastUrl = location.href;
                    this.run();
                }
            }, CFG.URL_CHECK_INTERVAL);
        },
    };

    // =========================================================================
    //  BOOT
    // =========================================================================
    AntiDetect.init();

    window.addEventListener('load', () => {
        LOG.info('boot', 'v2.0.0 启动');
        Shortcuts.init();
        UI.create();
        if (S.serviceActive) {
            setTimeout(() => Router.start(), 1500);
        }
    });
})();