// ==UserScript==
// @name         国标下载
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  支持从gb688.cn上下载国标的PDF图片格式文档
// @author       wcd
// @match        http://c.gb688.cn/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=gb688.cn
// @grant        none
// @license MIT

// @downloadURL none
// ==/UserScript==

(function() {
    'use strict';
$(function(){

   $("head").append(
  '<script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.5.1/jspdf.umd.min.js"></script>'
);
let my_script = `<script>
     function px2Num(px) {
         return Number(px.split("px")[0].toString());
     }

     function getPages(){
         if( $("canvas[id^=canvas_]").length > 0 ) {
             $("canvas[id^=canvas_]").delete();
         }

         var baseurl = "http://c.gb688.cn/bzgk/gb/";
         var pagecount = $("div.page").length;
         var pages = new Array(pagecount);
         var pagebg = new Array(pagecount);
         var title = $("title").text().split("|")[1].toString().trim();
         var pheight = $("#0").css("height");
         var pwidth = $("#0").css("width");

         $(".page").each(function(i, elem) {
             if (elem.hasAttribute("bg")) {
                 pagebg[i] = elem.getAttribute("bg");
             } else {
                 pagebg[i] = $(elem).children("span").first().css("background-image").split('"')[
                     1].split(/\\//).slice(-1)[0];
             }
         });

         //拼合图片
         $(".page").each(function(i, elem) {
             var canvasclone = $("canvas#canvas").clone();
             canvasclone.attr("id","canvas_"+i).css("background-color","#FFFFFFFF");
             $("#newimg").append(canvasclone);
             var canvas = document.getElementById('canvas_'+i);
             var ctx = canvas.getContext('2d');
             ctx.fillStyle="white";
             ctx.fillRect(0,0,px2Num(pwidth), px2Num(pheight));

             $("#imgContainer").append("<img id=img_" + i + " src='" + baseurl+pagebg[i] + "' />")
             var image = document.getElementById('img_'+i);

             image.addEventListener('load', e => {
                 $(elem).children("span").each(function(j,s){
                      ctx.drawImage(image, -px2Num($(s).css("background-position-x")), -px2Num($(s).css("background-position-y")),  119, 168,
                      $(s).attr("class").split('-')[1]*119, $(s).attr("class").split('-')[2]*168, 119, 168);
                 });
             });

         });
     }

     function isimgComplete(imgs){
         //$("img[id^=img_]")
         flag = true;
         for(i=0;i<imgs.length;i++){
             flag=flag && imgs[i].complete;
         }
         return flag;
     }

     function downloadPDF(){
         if( $("canvas[id^=canvas_]").length == 0 ) {
             alert("请先点击获取页面！");
             return;
         }

         var images = $("img[id^=img_]");
         //alert(isimgComplete(images));
         if(!isimgComplete(images)){
             alert("页面尚未提取完，稍后再试");
             return;
         }

         var pheight = $("#0").css("height");
         var pwidth = $("#0").css("width");
         const { jsPDF } = window.jspdf;
         const pdf = new jsPDF('p','px',[px2Num(pwidth), px2Num(pheight)]);

         var title = $("title").text().split("|")[1].toString().trim();

         let [imgX, imgY] = [595.28, 841.89];
         let imgHeight = imgX / (px2Num(pwidth) / px2Num(pheight));

         $("canvas[id^=canvas_]").each(function(i,e){
             pdf.addImage(document.getElementById('canvas_'+i).toDataURL('image/jpeg'), 'jpeg', 0, 0, px2Num(pwidth), px2Num(pheight), '', 'MEDDIUM');
             //pdf.addImage(document.getElementById('canvas_'+i).toDataURL('image/png'), 'jpeg', 0, 0, imgX, imgHeight, '', 'SLOW');
             pdf.addPage();
         });

         let targetPage = pdf.internal.getNumberOfPages();
         pdf.deletePage(targetPage); // 删除最后一页

         pdf.save(title + ".pdf");
     }

      function downloadPDF0(){
         while($("canvas[id^=canvas_]").length < $(".page").length){
             setTimeout(function(){

             },1000);
         }
      }

 </script>`;

let source_img = `
     <div id="canvas_container">
     <input type="button" value="获取页面" onclick="getPages()"/>
     <input type="button" value="下载pdf" onclick="downloadPDF()"/>
     </div>
     <div id="imgContainer" style="display:none;"><img id="source" src=""></div>
     <div id="newimg" width="1190px"></div>
     <canvas id="canvas" width="1190px" height="1680px" style="display:none;"></canvas>`;

let style = `
     <style>
         #canvas_container {
         position: fixed;
         height: 30px;
         width: 150px;
         top: 50px;
         left: 10px;
         border: 1px;
         /*background-color: #00ff0099;*/
         border-radius: 3px;
         }
     </style>
 `;

$("head").append(style);
$("body").append(source_img);
$("body").append(my_script);
});

})();