// ==UserScript==
// @name         Pixiv 图片批量下载器
// @namespace    pixiv-batch-downloader
// @version      2.1
// @description  在Pixiv作品页面添加下载按钮，选择文件夹后逐张下载所有图片到同一目录
// @author       WorkBuddy
// @match        https://www.pixiv.net/artworks/*
// @grant        GM_xmlhttpRequest
// @connect      i.pximg.net
// @connect      www.pixiv.net
// @license MIT
// ==/UserScript==

(function() {
    'use strict';

    function createButton() {
        const btn = document.createElement('button');
        btn.id = 'pxiv-dl-btn';
        btn.innerHTML = '📥 下载全部图片';
        btn.style.cssText = `
            position: fixed;
            top: 80px;
            right: 20px;
            z-index: 99999;
            padding: 12px 24px;
            background: #0096fa;
            color: white;
            border: none;
            border-radius: 10px;
            font-size: 15px;
            font-weight: bold;
            cursor: pointer;
            box-shadow: 0 4px 12px rgba(0,150,250,0.4);
            transition: all 0.2s;
        `;
        btn.onmouseenter = () => btn.style.background = '#0078d4';
        btn.onmouseleave = () => btn.style.background = '#0096fa';
        return btn;
    }

    function createProgress() {
        const div = document.createElement('div');
        div.id = 'pxiv-dl-progress';
        div.style.cssText = `
            position: fixed;
            top: 130px;
            right: 20px;
            z-index: 99999;
            padding: 12px 20px;
            background: rgba(0,0,0,0.85);
            color: white;
            border-radius: 8px;
            font-size: 13px;
            display: none;
            min-width: 240px;
            max-width: 340px;
            line-height: 1.6;
        `;
        return div;
    }

    function sanitizeFilename(name) {
        return name.replace(/[<>:"/\\|?*]/g, '_').trim() || 'pixiv_artwork';
    }

    async function downloadAll() {
        const btn = document.getElementById('pxiv-dl-btn');
        const progress = document.getElementById('pxiv-dl-progress');
        btn.disabled = true;
        btn.style.opacity = '0.6';
        progress.style.display = 'block';
        progress.innerHTML = '';

        // 进度文本行
        const statusLine = document.createElement('div');
        progress.appendChild(statusLine);

        // 进度条
        const barWrapper = document.createElement('div');
        barWrapper.style.cssText = 'margin-top:8px;width:100%;height:6px;background:rgba(255,255,255,0.2);border-radius:3px;overflow:hidden;';
        const bar = document.createElement('div');
        bar.style.cssText = 'height:100%;background:#00e676;width:0%;border-radius:3px;transition:width 0.3s;';
        barWrapper.appendChild(bar);
        progress.appendChild(barWrapper);

        try {
            const match = window.location.href.match(/artworks\/(\d+)/);
            if (!match) {
                statusLine.textContent = '❌ 无法获取作品ID';
                return;
            }
            const illustId = match[1];

            let title = illustId;
            const h1 = document.querySelector('h1');
            if (h1 && h1.textContent.trim()) {
                title = h1.textContent.trim();
            }
            title = sanitizeFilename(title);

            // 获取图片列表
            statusLine.textContent = '⏳ 获取图片列表...';
            const resp = await fetch('https://www.pixiv.net/ajax/illust/' + illustId + '/pages', {
                credentials: 'include'
            });
            const data = await resp.json();

            if (data.error || !data.body) {
                statusLine.textContent = '❌ 获取失败: ' + (data.message || '未知错误');
                return;
            }

            const pages = data.body;
            const total = pages.length;

            if (total === 0) {
                statusLine.textContent = '❌ 没有找到图片';
                return;
            }

            // 让用户选择文件夹
            statusLine.textContent = '📁 请在弹出的对话框中选择保存文件夹...';
            let dirHandle;
            try {
                dirHandle = await window.showDirectoryPicker({
                    mode: 'readwrite',
                    id: 'pixiv-downloads',
                    startIn: 'downloads'
                });
            } catch (e) {
                statusLine.textContent = '❌ 未选择文件夹，已取消';
                return;
            }

            // 在选定文件夹内创建以作品名命名的子文件夹
            const subDir = await dirHandle.getDirectoryHandle(title, { create: true });

            statusLine.textContent = '📦 共 ' + total + ' 张，开始下载到 ' + title + '/ 文件夹';

            let successCount = 0;
            let failCount = 0;

            for (let i = 0; i < total; i++) {
                const pageNum = i + 1;
                const url = pages[i].urls.original;
                const ext = url.split('.').pop();
                const filename = String(pageNum).padStart(3, '0') + '.' + ext;

                statusLine.textContent = '⏳ 下载中 ' + pageNum + '/' + total;
                bar.style.width = Math.round((i / total) * 100) + '%';

                try {
                    // 用 GM_xmlhttpRequest 下载图片（绕过CORS，带Referer）
                    const blob = await new Promise((resolve, reject) => {
                        GM_xmlhttpRequest({
                            method: 'GET',
                            url: url,
                            headers: {
                                'Referer': 'https://www.pixiv.net/'
                            },
                            responseType: 'blob',
                            onload: function(response) {
                                resolve(response.response);
                            },
                            onerror: function(err) {
                                reject(err);
                            },
                            ontimeout: function() {
                                reject(new Error('timeout'));
                            }
                        });
                    });

                    // 写入文件夹
                    const fileHandle = await subDir.getFileHandle(filename, { create: true });
                    const writable = await fileHandle.createWritable();
                    await writable.write(blob);
                    await writable.close();

                    successCount++;
                    // 适当延迟，避免下载过快
                    await new Promise(r => setTimeout(r, 300));

                } catch (err) {
                    console.error('Failed:', url, err);
                    failCount++;
                    statusLine.textContent = '⚠️ 第 ' + pageNum + ' 张失败，跳过继续...';
                    await new Promise(r => setTimeout(r, 800));
                }
            }

            bar.style.width = '100%';

            let resultMsg = '✅ 完成！成功 ' + successCount + '/' + total;
            if (failCount > 0) {
                resultMsg += '（失败 ' + failCount + ' 张）';
            }
            statusLine.innerHTML = resultMsg + '<br><span style="font-size:11px;opacity:0.7">图片已保存到你选择的文件夹下的「' + title + '」子文件夹中</span>';

            setTimeout(() => {
                progress.style.display = 'none';
            }, 8000);

        } catch (e) {
            statusLine.textContent = '❌ 出错: ' + e.message;
            console.error(e);
        } finally {
            btn.disabled = false;
            btn.style.opacity = '1';
        }
    }

    function init() {
        if (document.getElementById('pxiv-dl-btn')) return;

        const btn = createButton();
        const progress = createProgress();
        btn.onclick = downloadAll;

        document.body.appendChild(btn);
        document.body.appendChild(progress);
    }

    setInterval(() => {
        if (window.location.href.includes('/artworks/') && !document.getElementById('pxiv-dl-btn')) {
            init();
        }
    }, 1000);
})();