// ==UserScript==
// @name         行业标准信息PDF下载
// @namespace    http://tampermonkey.net/
// @version      2025.3.5
// @description  自动下载行业标准信息图片并合并为PDF（带进度显示）
// @author       Shuaima
// @match        https://hbba.sacinfo.org.cn/attachment/onlineRead/*
// @require      https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.5.1/jspdf.umd.min.js
// @grant        GM_xmlhttpRequest
// @grant        GM_download
// @grant        GM_notification
// @connect      hbba.sacinfo.org.cn
// ==/UserScript==

(function() {
    'use strict';
    
    const pathParts = window.location.pathname.split('/');
    const name = pathParts[3] || 'default_hash';
    let pageNum = 0;
    let imgUrls = [];
    const doc = new jspdf.jsPDF();
    let downloadBtn = null;

    // 验证页面
    if (!name || pathParts[2] !== 'onlineRead') {
        GM_notification({text: '请在标准阅读页面使用本脚本！', timeout: 5000});
        return;
    }

    function createButton() {
        downloadBtn = document.createElement('button');
        downloadBtn.id = 'pdfDownloadBtn';
        downloadBtn.style = `
            position: fixed;
            top: 20px;
            right: 20px;
            padding: 7px 15px;
            background: #219677;
            color: white;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            z-index: 9999;
            box-shadow: 0 2px 5px rgba(0,0,0,0.3);
            transition: all 0.3s;
        `;
        downloadBtn.textContent = '下载PDF';
        downloadBtn.onclick = startDownload;
        document.body.appendChild(downloadBtn);
    }

    function startDownload() {
        // 重置状态
        pageNum = 0;
        imgUrls = [];
        updateButton('准备下载...', true);
        
        fetchNextPage();
    }

    function updateButton(text, disabled = false) {
        if (!downloadBtn) return;
        downloadBtn.textContent = text;
        downloadBtn.style.background = disabled ? '#808080' : '#219677';
        downloadBtn.disabled = disabled;
    }

    function fetchNextPage() {
        const url = `https://hbba.sacinfo.org.cn/hbba_onlineRead_page/${name}/${pageNum}.png?t=1`;
        
        GM_xmlhttpRequest({
            method: 'GET',
            url: url,
            responseType: 'blob',
            headers: {
                'Referer': 'https://hbba.sacinfo.org.cn/',
                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36'
            },
            onload: function(response) {
                if (response.status === 200) {
                    const blob = response.response;
                    imgUrls.push(URL.createObjectURL(blob));
                    pageNum++;
                    updateButton(`下载中...（已下载 ${pageNum} 页）`, true);
                    setTimeout(fetchNextPage, 1000);
                } else {
                    endDownload();
                }
            },
            onerror: function() {
                endDownload();
            }
        });
    }

    function endDownload() {
        if (pageNum === 0) {
            updateButton('下载失败，点击重试');
            GM_notification({text: '下载失败，请重试！', timeout: 3000});
            return;
        }
        
        updateButton('生成PDF中...', true);
        
        generatePDF();
    }

    function generatePDF() {
        if (imgUrls.length === 0) return;

        const img = new Image();
        img.src = imgUrls[0];
        img.onload = function() {
            const imgWidth = doc.internal.pageSize.getWidth();
            const imgHeight = (img.height * imgWidth) / img.width;

            doc.addImage(imgUrls[0], 'JPEG', 0, 0, imgWidth, imgHeight);
            
            for (let i = 1; i < imgUrls.length; i++) {
                doc.addPage();
                doc.addImage(imgUrls[i], 'JPEG', 0, 0, imgWidth, imgHeight);
            }

            doc.save(`${name}.pdf`);
            
            // 清理资源
            imgUrls.forEach(url => URL.revokeObjectURL(url));
            updateButton('下载完成 ✔️');
            setTimeout(() => updateButton('下载PDF'), 5000);
        };
    }

    // 初始化
    if (name !== 'default_hash') {
        setTimeout(createButton, 1000);
    }
})();