// ==UserScript==
// @name         博看网PDF下载助手
// @namespace    http://tampermonkey.net/
// @version      2025.3.4
// @description  在博看网页面直接下载书籍/期刊为PDF
// @author       Shuaima
// @match        *://new.bookan.com.cn/page/detail.html?*
// @grant        GM_xmlhttpRequest
// @grant        GM_notification
// @connect      api.bookan.com.cn
// @connect      img1-qn.bookan.com.cn
// @require      https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.4.0/jspdf.umd.min.js
// ==/UserScript==

(function() {
    'use strict';
    const { jsPDF } = window.jspdf;

    // 添加下载按钮
    function addDownloadButton() {
        const btn = document.createElement('button');
        btn.innerHTML = '下载PDF';
        btn.style.cssText = `
            padding: 7px 15px;
            background: #2196F3;
            color: white;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            z-index: 9999;
            box-shadow: 0 2px 5px rgba(0,0,0,0.3);
        `;
        btn.addEventListener('click', initDownload);
        // 查找mt20类名的元素并添加按钮
        const mt20Elements = document.querySelectorAll('.mt20');
        if (mt20Elements.length > 0) {
            mt20Elements[0].appendChild(btn);
        } else {
            console.error('未找到类名为mt20的元素');
        }
        
        return btn;
    }

    // 获取URL参数
    function getUrlParams() {
        const params = new URLSearchParams(window.location.search);
        return {
            type: params.get('type'),
            id: params.get('id')
        };
    }

    // API请求封装
    function apiRequest(url, params) {
        return new Promise((resolve, reject) => {
            GM_xmlhttpRequest({
                method: 'GET',
                url: `${url}?${new URLSearchParams(params)}`,
                responseType: 'json',
                onload: (res) => {
                    if (res.status === 200 && res.response?.code === 0) {
                        resolve(res.response.data);
                    } else {
                        reject(new Error('API请求失败'));
                    }
                },
                onerror: (err) => reject(err)
            });
        });
    }

    // 获取期刊信息
    async function getJournalInfo(id, type) {
        return apiRequest('https://api.bookan.com.cn/resource/issueInfoList', {
            instanceId: 12696,
            isDetail: 1,
            issueIds: id,
            resourceType: type
        }).then(data => data[0]);
    }

    // 获取图片哈希列表
    async function getImageHashes(resourceId, issueId, pageCount, type) {
        return apiRequest('https://api.bookan.com.cn/resource/getHash', {
            resourceId: resourceId,
            issueId: issueId,
            start: 1,
            end: pageCount,
            resourceType: type
        });
    }

    // 下载单张图片
    function downloadImage(url) {
        return new Promise((resolve, reject) => {
            GM_xmlhttpRequest({
                method: 'GET',
                url: url,
                responseType: 'blob',
                onload: (res) => res.status === 200 ? resolve(res.response) : reject(),
                onerror: reject
            });
        });
    }

    // 生成PDF
    async function createPDF(images, filename) {
        const doc = new jsPDF('p', 'mm', 'a4');
        const pageWidth = doc.internal.pageSize.getWidth();
        const pageHeight = doc.internal.pageSize.getHeight();

        for (let i = 0; i < images.length; i++) {
            if (i > 0) doc.addPage();
            const imgUrl = URL.createObjectURL(images[i]);
            doc.addImage(imgUrl, 'JPEG', 0, 0, pageWidth, pageHeight);
            URL.revokeObjectURL(imgUrl);
        }
        doc.save(filename);
    }

    // 主下载流程
    async function initDownload() {
        const downloadButton = document.querySelector('button');
        try {
            const { type, id } = getUrlParams();
            if (!type || !id) throw new Error('未找到有效参数');

            // 获取期刊信息
            const info = await getJournalInfo(id, type);
            const { resourceId, issueId, count: pageCount } = info;

            // 获取哈希列表
            const hashes = await getImageHashes(resourceId, issueId, pageCount, type);

            // 下载所有图片
            const images = [];
            const totalImages = hashes.length;
            let downloadedImages = 0;

            for (const hashItem of hashes) {
                const imgUrl = `http://img1-qn.bookan.com.cn/jpage8/${resourceId}/${resourceId}-${issueId}/${hashItem.hash}_big.jpg`;
                const blob = await downloadImage(imgUrl);
                images.push({ blob, page: hashItem.page });
                downloadedImages++;
                const progress = Math.round((downloadedImages / totalImages) * 100);
                downloadButton.innerHTML = `下载中 ${progress}%`;
            }

            // 按页码排序
            images.sort((a, b) => a.page - b.page);

            // 生成PDF
            const filename = `${info.resourceName}_${info.issueName}.pdf`.replace(/[\\/]/g, '_');
            await createPDF(images.map(i => i.blob), filename);

            downloadButton.innerHTML = '下载完成';
            GM_notification({
                title: '下载完成',
                text: `文件已保存为：${filename}`,
                timeout: 5000
            });

        } catch (error) {
            downloadButton.innerHTML = '下载失败';
            GM_notification({
                title: '下载失败',
                text: error.message,
                timeout: 5000
            });
        }
    }

    // 监听页面加载完成事件
    window.addEventListener('load', function() {
        // 等待两秒后初始化
        setTimeout(function() {
            addDownloadButton();
        }, 1000);
    });
})();