// ==UserScript==
// @name         Wenku Doc Downloader
// @namespace    http://tampermonkey.net/
// @version      0.5
// @description  下载“百度文库”“豆丁网”文档，仅支持导出为txt文档或图片型的pdf。
// @author       allenlv2690@gmail.com
// @match        https://wenku.baidu.com/view/*
// @match        https://www.docin.com/p-*
// @icon         https://www.google.com/s2/favicons?domain=limestart.cn
// @grant        none
// @license      GPL-3.0-only
// @create       2021-11-22
// @note         修复了“pdf元素数量>2，doc元素数量=1”时不能下载文档的bug
// @note         特此感谢“chmdir”的反馈
// @note         【图片下载合并器】没有更新
// @downloadURL none
// ==/UserScript==

/*
*  附属功能函数部分
*/

function createAndDownloadFile(fileName, content) {
    // 创建并下载文件
    var aTag = document.createElement('a');
    var blob = new Blob([content]);
    aTag.download = fileName;
    aTag.href = URL.createObjectURL(blob);
    aTag.click();
    URL.revokeObjectURL(blob);
}

function formatText(text){
    // 用于纯文本文档的文本美化
	var reg_exp_1 = new RegExp(" [(]?=[\u4e00-\u9fa5] [)]");
	var reg_exp_2 = new RegExp("(?<=TEMP[\u4e00-\u9fa5]) ");
	var reg_exp_3 = new RegExp("(?<=[\u4e00-\u9fa5]) (?=[\u4e00-\u9fa5])");

	var text_1 = text.replace(reg_exp_1, "TEMP");
	var text_2 = text_1.replace(reg_exp_2, "");
	var text_3 = text_2.replace("TEMP", "");
	var text_final = text_3.replace(/ /g, " ");
	return text_final;
}

function formatText2(text) {
    // 用于图形文字混合型文档的文本美化
    var reg_exp = new RegExp("[  ]{2,}");
    var content_1 = text.replace(reg_exp, "\n");

    var content_2 = content_1.replace(/[  ]\n/g, "\n");

    var reg_exp_2 = new RegExp("\n[   ]*\n*\n");
    var content_3 = content_2.replace(reg_exp_2, "\n");

    var reg_exp_3 = new RegExp(" *\n * ");
    var content_4 = content_3.replace(reg_exp_3, "\n");

    var content_5 = content_4.replace(/[  ]/g, " ");
    var final_content = content_5.replace(/[ \n]精选文档[ \n]/g).replace(/\n{2,}/g, "\n");

    return final_content;
}

/*
*  主要功能函数部分
*/

function readAll() {
    var read_all_btn = document.getElementsByClassName("read-all")[0];
    // 如果存在“继续阅读”的按钮
    if (read_all_btn) {
        // 点击“继续阅读”按钮
        read_all_btn.click();
    }
    // 如果点击完之后仍旧存在该按钮，递归调用自身
    // read_all_btn = document.getElementsByClassName("read-all")[0];
    // if (read_all_btn) {
    //    readAll();
    // }
    else{
        alert("文档已经完全展开，可以导出");
        var init_btn = document.getElementsByClassName("init-btn")[0];
        var save_doc_btn = document.getElementsByClassName("save-doc-btn")[0];
        init_btn.style.display = "none";
        save_doc_btn.style.removeProperty("display");
    }
}

function savePDFData() {
    // 存储pdf型data（假定是内容是pic）
    alert("Function savePDFData was called.");
    var pic_urls = document.getElementsByClassName("reader-pic-item");
    var text_list = [];
    // 去掉前缀
    var reg_exp_1 = new RegExp(": ?url[(]");
    // 去掉后缀
    var reg_exp_2 = new RegExp("[)]; ?background-position");

    for (var i = 0; i < pic_urls.length; i++){
        var whole_text = pic_urls[i].getAttribute("style");
        var de_pretext = whole_text.split(reg_exp_1)[1];
        var url = de_pretext.split(reg_exp_2)[0];
        text_list.push(url);
    }

    text_list[0] = text_list[0].replace(/"/g, "");
    var content = text_list.join("\n");
    createAndDownloadFile("urls.csv", content);
}

function saveDocData() {
    // 存储doc型data（内容是text）
    alert("Function saveDocData was called.");
    // 获取文本
	var text_elements = document.getElementsByClassName("reader-word-layer");
	var texts = [];
	for (var elem of text_elements){
		texts.push(elem.textContent);
	}
	// 美化后导出文本
	var origin_content = texts.join("");
	var content = formatText(origin_content);
	createAndDownloadFile("纯文本文档.txt", content);
}

function savePPTData() {
    // 存储ppt型data（内容是pic）
    alert("Function savePPTData was called.");
    var pic_elements = document.getElementsByClassName("ppt-image-wrap");
    var pic_urls = [];

    for (var elem of pic_elements) {
        var pic_obj = elem.children[0];
        var url = pic_obj.src;
        pic_urls.push(url);
    }

    var content = pic_urls.join("\n");
    createAndDownloadFile("urls.csv", content);
}

function saveExcelData() {
    // 1. 拿到表格
    var table_pic = document.getElementsByClassName("reader-pic-item")[0];
    var url = table_pic.style.getPropertyValue("background-image");
    // 获取图片地址
    var pure_url = url.slice(5, -2);

    // 2. 拿到表格内文字信息
    var text_elems = document.getElementsByClassName("reader-word-layer");
    var text_list = [];
    for (var elem of text_elems) {
    	text_list.push(elem.textContent);
    }
    var _text = text_list.join("\n");
    // 替换奇怪的空格
    var text = _text.replace(/ /g, " ");

    // 3. 合并至一个字符串，然后导出
    var head = "表格图形链接如下（复制到浏览器中打开）：";
    var content = head + "\n\n" + pure_url + "\n\n" + text;
    createAndDownloadFile("图片地址和表格内容.txt", content);
}

function saveDocAndPicData() {
    // 对于文字和图形混合型的data只能存储其中的纯文字
    alert("Function saveDocAndPicData was called.");
    // 获取文本
	var text_elements = document.getElementsByClassName("reader-word-layer");
	var texts = [];
	for (var elem of text_elements){
		texts.push(elem.textContent);
	}
    // 处理文本中的过长空格
    var origin_content = texts.join("");
	// 美化后导出文本
	var content = formatText2(origin_content);
	createAndDownloadFile("纯文本文档.txt", content);
}

function savePdfWithTitleData() {
    // 这是带有文字标题行的pdf文档，将直接忽略其中的标题行
    savePDFData();
}

function detectType() {
    // 分别尝试获取相应元素列表，若列表长度为0则不存在相应元素，否则存在
    var pdf = document.getElementsByClassName("reader-pic-item").length;
    var doc = document.getElementsByClassName("reader-word-layer").length;
    var ppt = document.getElementsByClassName("ppt-image-wrap").length;
    // 判断文档类别
    if (pdf && !doc && !ppt) {
        return "pdf";
    }
    else if (doc && !pdf && !ppt) {
        return "doc";
    }
    else if (ppt && !pdf && !doc) {
        return "ppt";
    }
    else if (pdf === 1 && doc > 1 && !ppt) {
        return "excel";
    }
    else if (pdf > 2 && doc > 2 && !ppt) {
        return "docANDpic";
    }
    else if (pdf > 2 && doc === 1 && !ppt) {
        return "pdfWithTitle"
    }
    else {
        return {"pdf元素数量": pdf, "doc元素数量": doc, "ppt元素数量": ppt};
    }
}

function saveData() {
    // 存储文档数据到本地
    var category = detectType();
    if (category === "pdf"){
        savePDFData();
    }
    else if (category === "doc") {
        saveDocData();
    }
    else if (category === "ppt") {
        savePPTData();
    }
    else if (category === "excel") {
        saveExcelData();
    }
    else if (category === "docANDpic") {
        saveDocAndPicData();
    }
    else if (category === "pdfWithTitle") {
        savePdfWithTitleData();
    }
    else {
        var info = [];
        for (var key in category){
            info.push(key + " : " + category[key]);
        }
        alert("未知文档类型\n" + info.join("\n"));
    }
}

/*
*  主函数部分
*/

function baiduWenku() {
    // 创建脚本启动按钮1、2
    var btn_1 = document.createElement("button");
    var btn_2 = document.createElement("button");
    // 设定按钮1、2样式
    btn_1.setAttribute("class", "init-btn");
    btn_1.style.height = "25px";
    btn_1.style.width = "50%";
    btn_1.style.marginLeft = "25%";
    btn_1.style.backgroundColor = "blue";

    btn_2.setAttribute("class", "save-doc-btn");
    btn_2.style.height = "25px";
    btn_2.style.width = "50%";
    btn_2.style.marginLeft = "25%";
    btn_2.style.backgroundColor = "green";
    btn_2.style.display = "none";

    // 绑定主函数
    btn_1.addEventListener("click", readAll);
    btn_2.addEventListener("click", saveData);
    // 添加按钮元素到页面
    document.body.appendChild(btn_1);
    document.body.appendChild(btn_2);
    // 确认主程序加载完毕
    console.log("Program Loaded");
}

function docin() {
    // 创建脚本启动按钮
    var btn = document.createElement("button");
    // 设定按钮1、2样式
    btn.style.height = "25px";
    btn.style.width = "50%";
    btn.style.marginLeft = "25%";
    btn.style.backgroundColor = "green";

    // 绑定主函数
    var printPage = function() {window.print();};
    btn.addEventListener("click", printPage);
    // 添加按钮元素到页面
    document.body.appendChild(btn);
    // 确认主程序加载完毕
    console.log("Program Loaded");
}

function main() {
    var host = window.location.host;
    if (host === "wenku.baidu.com") {
        baiduWenku();
    }
    else if (host === "www.docin.com") {
        docin();
    }
    else {
        console.log("匹配到了无效网页");
    }
}

main();