// ==UserScript==
// @name         知网论文PDF批量下载(正式版)
// @namespace    wujiaxin1949l@gmail.com
// @version      1.1
// @description  在知网搜索论文后论文名字左侧选择你想要下载的论文，在下载小窗口点击“开始批量下载”即可。支持重复下载检测，窗口随标题长度自适应展开
// @author       Vachel
// @match        *://*.cnki.net/*
// @grant        GM_xmlhttpRequest
// @grant        GM_download
// @license      MIT
// @run-at       document-idle
// @downloadURL https://update.greasyfork.icu/scripts/571678/%E7%9F%A5%E7%BD%91%E8%AE%BA%E6%96%87PDF%E6%89%B9%E9%87%8F%E4%B8%8B%E8%BD%BD%28%E6%AD%A3%E5%BC%8F%E7%89%88%29.user.js
// @updateURL https://update.greasyfork.icu/scripts/571678/%E7%9F%A5%E7%BD%91%E8%AE%BA%E6%96%87PDF%E6%89%B9%E9%87%8F%E4%B8%8B%E8%BD%BD%28%E6%AD%A3%E5%BC%8F%E7%89%88%29.meta.js
// ==/UserScript==


(function() {
    'use strict';

    let isDragging = false;
    let currentX, currentY, initialX, initialY, xOffset = 0, yOffset = 0;
    const downloadHistory = new Set();

    const statusUpdater = {
        _selectedCount: 0,
        _isDownloading: false,
        setCount: function(count) { this._selectedCount = count; this.render(); },
        setDownloading: function(active) { this._isDownloading = active; this.render(); },
        setComplete: function() {
            const btn = document.getElementById('apple-start-btn');
            if (btn) {
                btn.style.background = "#28c840";
                btn.innerText = "✓ 搬运完毕";
                setTimeout(() => { this._isDownloading = false; this.render(); }, 2500);
            }
        },
        render: function() {
            const statusDiv = document.getElementById('apple-status');
            const btn = document.getElementById('apple-start-btn');
            if (!statusDiv || !btn || this._isDownloading) return;

            statusDiv.innerHTML = `已选择 <span style="font-weight:700;color:#0071e3;">${this._selectedCount}</span> 篇文献`;
            btn.disabled = this._selectedCount === 0;
            btn.style.background = this._selectedCount === 0 ? "rgba(0,0,0,0.05)" : "#0071e3";
            btn.style.color = this._selectedCount === 0 ? "#86868b" : "white";
            btn.innerText = "开始批量下载";
        }
    };

    /* --- UI 部分保持原样 --- */
    function showAppleConfirm(duplicates, checkedElements) {
        if (document.getElementById('apple-confirm-overlay')) return;
        const overlay = document.createElement('div');
        overlay.id = 'apple-confirm-overlay';
        overlay.setAttribute('style', `position:fixed; top:0; left:0; width:100%; height:100%; background:rgba(0,0,0,0.2); backdrop-filter:blur(4px); z-index:2147483647; display:flex; align-items:center; justify-content:center;`);
        const dialog = document.createElement('div');
        dialog.setAttribute('style', `width: 320px; max-height: 80vh; background: rgba(255,255,255,0.85); backdrop-filter: blur(30px) saturate(180%); border-radius: 22px; box-shadow: 0 20px 60px rgba(0,0,0,0.2); display: flex; flex-direction: column; animation: applePop 0.3s cubic-bezier(0.34, 1.56, 0.64, 1); overflow: hidden; border: 0.5px solid rgba(255,255,255,0.4);`);
        dialog.innerHTML = `
            <div style="padding: 24px 20px; text-align: center;">
                <div style="font-size: 32px; margin-bottom: 12px;">⚠️</div>
                <h3 style="margin: 0 0 8px; font-size: 17px; font-weight: 600; color: #000;">发现重复项目</h3>
                <p style="margin: 0 0 16px; font-size: 13px; color: #3a3a3c; line-height: 1.4;">以下文献已在本次会话中下载过：</p>
                <div style="max-height: 250px; overflow-y: auto; background: rgba(0,0,0,0.04); border-radius: 12px; padding: 10px; text-align: left;">
                    ${duplicates.map(t => `<div style="font-size: 12px; color: #1d1d1f; margin-bottom: 8px; line-height: 1.5; border-bottom: 0.5px solid rgba(0,0,0,0.05); padding-bottom: 4px;">${t}</div>`).join('')}
                </div>
            </div>
            <div style="display: flex; border-top: 0.5px solid rgba(0,0,0,0.15);">
                <button id="apple-cancel-task" style="flex:1; padding:16px; background:transparent; border:none; color:#007aff; font-size:16px; cursor:pointer; font-family:inherit;">中止</button>
                <button id="apple-skip-task" style="flex:1; padding:16px; background:transparent; border:none; color:#007aff; font-size:16px; font-weight:600; border-left:0.5px solid rgba(0,0,0,0.15); cursor:pointer; font-family:inherit;">跳过并下载</button>
            </div>`;
        overlay.appendChild(dialog);
        document.body.appendChild(overlay);
        document.getElementById('apple-cancel-task').onclick = () => overlay.remove();
        document.getElementById('apple-skip-task').onclick = () => {
            overlay.remove();
            const freshItems = checkedElements.filter(box => {
                const title = box.closest('tr').querySelector('a.fz14')?.innerText.trim();
                return !downloadHistory.has(title);
            });
            processBatch(freshItems);
        };
    }

    function initAppleUI() {
        if (document.getElementById('apple-manager')) return;
        const manager = document.createElement('div');
        manager.id = 'apple-manager';
        manager.setAttribute('style', `position:fixed; top:100px; right:30px; width:200px; z-index:99999; background:rgba(255,255,255,0.7); backdrop-filter:blur(20px) saturate(180%); border-radius:18px; border:1px solid rgba(255,255,255,0.4); box-shadow:0 8px 32px rgba(0,0,0,0.1); font-family:-apple-system,BlinkMacSystemFont,sans-serif; overflow:hidden;`);
        manager.innerHTML = `
            <div id="apple-handle" style="padding:10px; background:rgba(0,0,0,0.03); cursor:grab; text-align:center; font-size:10px; font-weight:700; color:#888; letter-spacing:1px;">CNKI MASTER</div>
            <div style="padding:15px;">
                <div id="apple-status" style="font-size:12px; margin-bottom:12px; text-align:center;">等待选取...</div>
                <button id="apple-start-btn" style="width:100%; padding:10px; border:none; border-radius:10px; font-size:13px; font-weight:600; cursor:pointer; transition:0.2s;">开始批量下载</button>
            </div>`;
        document.body.appendChild(manager);
        const style = document.createElement("style");
        style.innerText = `@keyframes applePop { from { transform:scale(1.1); opacity:0; } to { transform:scale(1); opacity:1; } }`;
        document.head.appendChild(style);
        const handle = document.getElementById('apple-handle');
        handle.onmousedown = (e) => { initialX = e.clientX - xOffset; initialY = e.clientY - yOffset; isDragging = true; };
        window.onmousemove = (e) => { if (isDragging) { currentX = e.clientX - initialX; currentY = e.clientY - initialY; xOffset = currentX; yOffset = currentY; manager.style.transform = `translate3d(${currentX}px, ${currentY}px, 0)`; } };
        window.onmouseup = () => { isDragging = false; };
        setInterval(() => {
            const count = document.querySelectorAll('input.cbItem:checked').length;
            statusUpdater.setCount(count);
        }, 800);
        document.getElementById('apple-start-btn').onclick = function() {
            const checked = Array.from(document.querySelectorAll('input.cbItem:checked'));
            const titlesInThisBatch = checked.map(box => box.closest('tr').querySelector('a.fz14')?.innerText.trim());
            const duplicates = titlesInThisBatch.filter(t => downloadHistory.has(t));
            if (duplicates.length > 0) showAppleConfirm(duplicates, checked);
            else processBatch(checked);
        };
    }

    /* --- 核心修复：改进的下载逻辑 --- */
    function processBatch(elements) {
        if (elements.length === 0) return;
        statusUpdater.setDownloading(true);
        const btn = document.getElementById('apple-start-btn');

        elements.forEach((box, i) => {
            const tr = box.closest('tr');
            const linkTag = tr.querySelector('a.fz14') || tr.querySelector('a[href*="detail"]');
            const rawTitle = linkTag?.innerText.trim();

            setTimeout(() => {
                btn.innerText = `处理中 ${i+1}/${elements.length}`;
                GM_xmlhttpRequest({
                    method: "GET",
                    url: linkTag.href,
                    headers: { "Referer": window.location.href }, // 模拟真实来源
                    onload: (res) => {
                        const doc = new DOMParser().parseFromString(res.responseText, 'text/html');
                        // 获取 PDF 下载链接
                        const pdfUrl = doc.querySelector('#pdfDown')?.href || doc.querySelector('.btn-dlpdf a')?.href;

                        if (pdfUrl) {
                            // 修复方案：放弃 GM_download，改用模拟真实点击
                            // 这样 IDM 能够正确截获下载流，且 Referer 不会丢失
                            const a = document.createElement('a');
                            a.href = pdfUrl;
                            a.style.display = 'none';
                            document.body.appendChild(a);
                            a.click();

                            downloadHistory.add(rawTitle);
                            setTimeout(() => a.remove(), 1000);
                        }
                        if (i === elements.length - 1) statusUpdater.setComplete();
                    }
                });
            }, i * 2500); // 增加间隔至 2.5s，提高知网在高频请求下的稳定性
        });
    }

    setTimeout(initAppleUI, 1000);
})();