// ==UserScript==
// @name         自然资源标准PDF下载
// @namespace    http://tampermonkey.net/
// @version      2025.3.7
// @description  自然资源标准化信息服务平台下载pdf功能
// @author       Shuaima
// @match        *://www.nrsis.org.cn/mnr_kfs/file/read/*
// @require      https://unpkg.com/pdf-lib@^1.17.1
// @require      https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.5.1/jspdf.umd.min.js
// @grant        GM_xmlhttpRequest
// @grant        GM_download
// ==/UserScript==

(function() {
    'use strict';

    const { PDFDocument } = PDFLib;
    let currentCode = '';
    let totalPages = 0;
    let loadedPages = 0;

    // 创建进度条
    function createProgressBar() {
        const container = document.createElement('div');
        container.style = `
            position: fixed;
            top: 70px;
            left: 20px;
            width: 200px;
            background: #f1f1f1;
            border-radius: 4px;
            padding: 10px;
            z-index: 9999;
            box-shadow: 0 2px 5px rgba(0,0,0,0.2);
            display: none;
        `;

        const progressBar = document.createElement('div');
        progressBar.style = `
            height: 20px;
            background: #e0e0e0;
            border-radius: 10px;
            overflow: hidden;
            margin-bottom: 8px;
        `;

        const progressFill = document.createElement('div');
        progressFill.style = `
            width: 0%;
            height: 100%;
            background: linear-gradient(90deg, #219677, #27ae60);
            transition: width 0.3s ease;
        `;

        const progressText = document.createElement('div');
        progressText.style = `
            text-align: center;
            font-size: 12px;
            color: #666;
        `;
        progressText.textContent = '准备中...';

        progressBar.appendChild(progressFill);
        container.appendChild(progressBar);
        container.appendChild(progressText);
        document.body.appendChild(container);

        return { container, progressFill, progressText };
    }

    // 创建下载按钮
    function createDownloadBtn() {
        const btn = document.createElement('button');
        btn.style =  `
            position: fixed;
            top: 20px;
            left: 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;
        `;
        btn.textContent = '下载PDF';
        btn.onclick = startDownloadProcess;
        document.body.appendChild(btn);
    }

    // 从URL获取code
    function getCodeFromURL() {
        const pathSegments = window.location.pathname.split('/');
        const code = pathSegments[pathSegments.length - 1];
        return code || '';
    }

    // 更新进度条
    function updateProgress(progressData) {
        progressData.progressFill.style.width = `${(loadedPages / totalPages * 100).toFixed(1)}%`;
        progressData.progressText.textContent = 
            `已下载 ${loadedPages}/${totalPages} 页 (${(loadedPages / totalPages * 100).toFixed(1)}%)`;
    }

    // 获取全部页面数据
    async function fetchAllPages(progressData) {
        const pdfDoc = await PDFDocument.create();
        totalPages = Page.size;
        loadedPages = 0;

        progressData.container.style.display = 'block';
        updateProgress(progressData);

        for (let i = 1; i <= totalPages; i++) {
            const pageData = await fetchPage(i);
            const pageDoc = await PDFDocument.load(pageData);
            const [copiedPage] = await pdfDoc.copyPages(pageDoc, [0]);
            pdfDoc.addPage(copiedPage);
            
            loadedPages++;
            updateProgress(progressData);
        }

        return await pdfDoc.save();
    }

    // 获取单页数据
    function fetchPage(pageNum) {
        return new Promise((resolve) => {
            GM_xmlhttpRequest({
                method: "POST",
                url: "/mnr_kfs/file/readPage",
                headers: {
                    "Content-Type": "application/x-www-form-urlencoded"
                },
                data: `code=${currentCode}&page=${pageNum}`,
                responseType: "text",
                onload: (res) => {
                    const base64Data = res.response;
                    const binaryData = base64ToArrayBuffer(base64Data);
                    resolve(binaryData);
                }
            });
        });
    }

    // 启动下载流程
    async function startDownloadProcess() {
        const progressData = createProgressBar();
        
        try {
            currentCode = getCodeFromURL();
            if (!currentCode) {
                alert('无法获取文档编号，请确认当前页面正确');
                return;
            }

            const pdfBytes = await fetchAllPages(progressData);
            const blob = new Blob([pdfBytes], { type: 'application/pdf' });
            
            GM_download({
                url: URL.createObjectURL(blob),
                name: `自然资源标准_${currentCode}.pdf`,
                saveAs: true
            });

            // 下载完成后隐藏进度条
            setTimeout(() => {
                progressData.container.style.display = 'none';
            }, 2000);
            
        } catch (err) {
            console.error('下载失败:', err);
            progressData.progressText.textContent = '下载失败，请刷新重试';
            progressData.progressFill.style.background = '#ff4757';
        }
    }

    // 初始化
    (function init() {
        window.render = function() {}; // 禁用原渲染
        createDownloadBtn();
    })();

    // Base64转换工具
    function base64ToArrayBuffer(base64) {
        const binaryString = atob(base64);
        const len = binaryString.length;
        const bytes = new Uint8Array(len);
        for (let i = 0; i < len; i++) {
            bytes[i] = binaryString.charCodeAt(i);
        }
        return bytes.buffer;
    }

})();