// ==UserScript==
// @name         智慧教材极速下载
// @namespace    https://scriptcat.org/zh-CN/users/211428
// @version      1.0.0
// @description  一键下载国家中小学智慧教育平台教材
// @author       ganjueqi
// @match        https://basic.smartedu.cn/*?*contentId=*
// @match        https://www.smartedu.cn/*?*contentId=*
// @match        https://teacher.vocational.smartedu.cn/*?*contentId=*
// @match        https://core.teacher.vocational.smartedu.cn/*?*contentId=*
// @grant        GM_xmlhttpRequest
// @grant        GM_setValue
// @grant        GM_getValue
// @grant        GM_openInTab
// @connect      s-file-2.ykt.cbern.com.cn
// @run-at       document-end
// @tag          教材下载 下载
// @icon        data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📘</text></svg>
// @license GPL-3.0
// ==/UserScript==

(function () {
    'use strict';

    // ---------- 样式（AI 风格，增加 cursor: grab） ----------
    const style = document.createElement('style');
    style.textContent = `
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        @keyframes fadeSlideIn {
            0% { opacity: 0; transform: translateY(20px) scale(0.9); }
            100% { opacity: 1; transform: translateY(0) scale(1); }
        }
        @keyframes fadeSlideOut {
            0% { opacity: 1; transform: translateY(0) scale(1); }
            100% { opacity: 0; transform: translateY(10px) scale(0.9); }
        }
        @keyframes pulseGlow {
            0%, 100% {
                box-shadow: 0 0 20px rgba(71, 118, 230, 0.5), 0 0 60px rgba(142, 84, 233, 0.3);
            }
            50% {
                box-shadow: 0 0 40px rgba(71, 118, 230, 0.8), 0 0 80px rgba(142, 84, 233, 0.5);
            }
        }

        .edu-download-btn {
            position: fixed;
            bottom: 30px;
            left: 30px;
            z-index: 9999;
            width: 80px;
            height: 80px;
            border-radius: 50%;
            background: linear-gradient(135deg, #4776E6, #8E54E9);
            animation: pulseGlow 3s ease-in-out infinite;
            cursor: grab;
            touch-action: none;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.3s ease;
            user-select: none;
            border: none;
            outline: none;
            color: #fff;
            font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
            backdrop-filter: blur(2px);
            -webkit-backdrop-filter: blur(2px);
        }
        .edu-download-btn::before {
            content: '';
            position: absolute;
            inset: 3px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.08);
            pointer-events: none;
        }
        .edu-download-btn:hover {
            transform: scale(1.10);
            animation: none;
            box-shadow: 0 0 40px rgba(71, 118, 230, 0.9), 0 0 80px rgba(142, 84, 233, 0.6);
        }
        .edu-download-btn:active {
            transform: scale(0.92);
            cursor: grabbing;
        }
        .edu-download-btn .icon {
            font-size: 24px;
            line-height: 1;
            transition: transform 0.3s;
            position: relative;
            z-index: 1;
            filter: drop-shadow(0 2px 4px rgba(0,0,0,0.2));
        }
        .edu-download-btn .label {
            font-size: 14px;
            font-weight: 700;
            letter-spacing: 0.8px;
            margin-top: 2px;
            position: relative;
            z-index: 1;
            text-shadow: 0 2px 8px rgba(0,0,0,0.25);
        }
        .edu-download-btn.loading .icon {
            animation: spin 1s linear infinite;
        }
        .edu-download-btn.loading {
            animation: none;
        }

        .edu-toast {
            position: fixed;
            bottom: 130px;
            left: 30px;
            background: rgba(20, 22, 36, 0.92);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            color: #fff;
            padding: 12px 24px;
            border-radius: 16px;
            font-size: 14px;
            font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
            box-shadow: 0 8px 32px rgba(0,0,0,0.35);
            z-index: 10000;
            animation: fadeSlideIn 0.3s ease;
            max-width: 320px;
            text-align: center;
            pointer-events: none;
            display: flex;
            align-items: center;
            gap: 10px;
            border: 1px solid rgba(255,255,255,0.06);
        }
        .edu-toast.error {
            background: rgba(60, 20, 30, 0.92);
            border-color: rgba(255, 80, 80, 0.2);
        }
        .edu-toast.success {
            background: rgba(20, 50, 40, 0.92);
            border-color: rgba(80, 255, 150, 0.2);
        }
        .edu-toast.hide {
            animation: fadeSlideOut 0.3s ease forwards;
        }
    `;
    document.head.appendChild(style);

    // ---------- 工具函数 ----------
    function getContentId() {
        const params = new URLSearchParams(window.location.search);
        const id = params.get('contentId');
        if (!id || !/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(id)) {
            return null;
        }
        return id;
    }

    async function fetchAccessToken() {
        const MAX_RETRIES = 3;
        const DELAY = 500;
        for (let attempt = 0; attempt < MAX_RETRIES; attempt++) {
            const keys = Object.keys(localStorage).filter(k =>
                k.includes('ND_UC_AUTH') || k.includes('nd_uc_auth')
            );
            if (keys.length === 0) {
                await sleep(DELAY);
                continue;
            }
            for (const key of keys) {
                const raw = localStorage.getItem(key);
                if (!raw) continue;
                let data;
                try { data = JSON.parse(raw); } catch { continue; }
                if (!data.value) continue;
                let parsed;
                try { parsed = JSON.parse(data.value); } catch { parsed = data.value; }
                if (parsed?.access_token) {
                    return parsed.access_token;
                }
            }
            await sleep(DELAY);
        }
        return null;
    }

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

    function showToast(message, type = 'info', duration = 3000) {
        const existing = document.querySelector('.edu-toast');
        if (existing) {
            existing.classList.add('hide');
            setTimeout(() => existing.remove(), 350);
        }
        const toast = document.createElement('div');
        toast.className = `edu-toast ${type}`;
        toast.textContent = message;
        document.body.appendChild(toast);
        setTimeout(() => {
            toast.classList.add('hide');
            setTimeout(() => toast.remove(), 350);
        }, duration);
    }

    // ---------- 核心下载 ----------
    async function handleDownload(btn) {
        if (btn.classList.contains('loading')) return;
        btn.classList.add('loading');

        try {
            const contentId = getContentId();
            if (!contentId) {
                showToast('当前页面没有有效的教材ID', 'error');
                btn.classList.remove('loading');
                return;
            }

            const token = await fetchAccessToken();
            if (!token) {
                showToast('未获取到登录令牌，请刷新页面重试', 'error');
                btn.classList.remove('loading');
                return;
            }

            const url = `https://s-file-2.ykt.cbern.com.cn/zxx/ndrv2/resources/tch_material/details/${contentId}.json`;
            const response = await new Promise((resolve, reject) => {
                GM_xmlhttpRequest({
                    method: 'GET',
                    url: url,
                    onload: resolve,
                    onerror: reject,
                    ontimeout: () => reject(new Error('请求超时'))
                });
            });

            if (response.status !== 200) {
                throw new Error(`API请求失败 (${response.status})`);
            }

            const data = JSON.parse(response.responseText);
            const source = data.ti_items?.find(item => item.ti_file_flag === 'source');
            if (!source || !source.ti_storages?.length) {
                throw new Error('未找到教材存储信息');
            }

            const parts = source.ti_storages.flatMap(s =>
                s.split('`').map(p => p.replace(/\s+/g, ' ').trim()).filter(Boolean)
            );
            let current = '';
            const candidates = [];
            for (const p of parts) {
                if (p.startsWith('http')) {
                    if (current) candidates.push(current);
                    current = p;
                } else {
                    current += p;
                }
            }
            if (current) candidates.push(current);
            const pdfUrl = candidates.find(u => u.toLowerCase().endsWith('.pdf'));
            if (!pdfUrl) {
                throw new Error('未找到PDF下载链接');
            }

            const downloadUrl = `${pdfUrl}?accessToken=${token}`;

            GM_openInTab(downloadUrl, { active: true });
            showToast('✅ 下载已在新标签页开始', 'success');
        } catch (err) {
            console.error('下载失败:', err);
            showToast(`❌ ${err.message || '未知错误'}`, 'error');
        } finally {
            btn.classList.remove('loading');
        }
    }

    // ---------- 创建可拖拽按钮（使用 pointer 事件，修复错位） ----------
    function createDraggableButton() {
        const btn = document.createElement('button');
        btn.className = 'edu-download-btn';
        btn.setAttribute('title', '点击下载教材 (快捷键 M)');
        btn.innerHTML = `
            <span class="icon">📘</span>
            <span class="label">教材下载</span>
        `;
        document.body.appendChild(btn);

        // 恢复保存的位置
        const savedPos = GM_getValue('eduBtnPos');
        if (savedPos) {
            btn.style.left = savedPos.left || '30px';
            btn.style.top = savedPos.top || '30px';
            btn.style.bottom = '';
            btn.style.right = '';
        }

        let startX = 0, startY = 0;
        let offsetX = 0, offsetY = 0;   // 指针相对于按钮左上角的偏移
        let isDragging = false;
        let wasDragged = false;
        const DRAG_THRESHOLD = 5;

        // ---------- pointer 事件 ----------
        function onPointerDown(e) {
            // 只响应鼠标左键或触摸（pointer 自动处理）
            if (e.button !== undefined && e.button !== 0) return;

            const rect = btn.getBoundingClientRect();
            offsetX = e.clientX - rect.left;
            offsetY = e.clientY - rect.top;
            startX = e.clientX;
            startY = e.clientY;
            wasDragged = false;
            isDragging = true;
            btn.style.cursor = 'grabbing';
            btn.setPointerCapture(e.pointerId);
            e.preventDefault();
        }

        function onPointerMove(e) {
            if (!isDragging) return;
            const dx = e.clientX - startX;
            const dy = e.clientY - startY;
            if (!wasDragged && Math.sqrt(dx*dx + dy*dy) > DRAG_THRESHOLD) {
                wasDragged = true;
            }
            if (wasDragged) {
                let newLeft = e.clientX - offsetX;
                let newTop = e.clientY - offsetY;
                // 边界限制
                const maxX = window.innerWidth - btn.offsetWidth;
                const maxY = window.innerHeight - btn.offsetHeight;
                newLeft = Math.max(0, Math.min(newLeft, maxX));
                newTop = Math.max(0, Math.min(newTop, maxY));
                btn.style.left = newLeft + 'px';
                btn.style.top = newTop + 'px';
                btn.style.bottom = '';
                btn.style.right = '';
            }
        }

        function onPointerUp(e) {
            if (!isDragging) return;
            isDragging = false;
            btn.style.cursor = 'grab';
            // 判断是拖拽还是点击
            if (wasDragged) {
                // 保存位置
                GM_setValue('eduBtnPos', {
                    left: btn.style.left,
                    top: btn.style.top
                });
            } else {
                // 点击触发下载
                handleDownload(btn);
            }
            wasDragged = false;
        }

        function onPointerCancel(e) {
            if (isDragging) {
                isDragging = false;
                btn.style.cursor = 'grab';
                wasDragged = false;
            }
        }

        // 注册事件
        btn.addEventListener('pointerdown', onPointerDown);
        document.addEventListener('pointermove', onPointerMove);
        document.addEventListener('pointerup', onPointerUp);
        document.addEventListener('pointercancel', onPointerCancel);

        // ---------- 键盘快捷键 ----------
        document.addEventListener('keydown', (e) => {
            if (e.key.toLowerCase() === 'm' &&
                !['INPUT', 'TEXTAREA', 'SELECT'].includes(e.target.tagName) &&
                !e.target.isContentEditable) {
                e.preventDefault();
                handleDownload(btn);
            }
        });

        // 初始光标
        btn.style.cursor = 'grab';

        // 欢迎提示
        setTimeout(() => {
            showToast('🤖 点击“教材下载”按钮获取教材（可拖拽）', 'info', 2800);
        }, 1000);

        return btn;
    }

    createDraggableButton();
})();