var fs = require('fs');
var request = require("request");
var path = require('path');

var src = "https://miscrofile.oss-cn-hangzhou.aliyuncs.com/root/question/data_structure2020/2020数据结构(第2章)/image3.png";

content=fs.readFileSync("output.json", "utf8");
list1 = content.match(/https:\/\/miscrofile.oss-cn-hangzhou.aliyuncs.com\/([^.]+)\.([a-zA-Z0-9]+)/g);
list2 = content.match(/https:\/\/miscrofile.oss-cn-hangzhou.aliyuncs.com/g);

writeFile(list1,0,null)
function writeFile(uriList,num){
    let uri=uriList[num];
    let pathString=uri.replace("https://miscrofile.oss-cn-hangzhou.aliyuncs.com/","");
    dir=pathString.replace(/([^\/]+)\.([a-zA-Z0-9]+)/,"");
    if(dir.charAt(dir.length-1)==="/"){
        dir=dir.slice(0,dir.length-1)
    }
    mkdirsSync(dir);
    if(fs.existsSync(pathString)){
        // console.log("N:"+num+" 已经存在");
        num++;
        if(num<uriList.length){
            writeFile(uriList,num);
        }
        return;
    }
    let writeStream = fs.createWriteStream(pathString);
    let option={
        url:encodeURI(uri),
        headers: {
            "Referer": "http://neep.learncoder.com/content/practice/practice?id=116&name=%E7%BD%91%E7%BB%9C%E5%B1%82",
            "User-Agent":"Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36"
        },
    }
    let readStream = request(option)
    
    readStream.pipe(writeStream);
    readStream.on('end', function() {
        // console.log('文件下载成功');
    });
    readStream.on('error', function(err) {
        console.log("N:"+num+" 失败 "+err);
        num++;
        if(num<uriList.length){
            writeFile(uriList,num);
        }
    })
    writeStream.on("finish", function() {
        console.log("N:"+num+" 成功 "+uri);
        writeStream.end();
        num++;
        if(num<uriList.length){
            writeFile(uriList,num);
        }
    });
}


// let writeStream = fs.createWriteStream('image.png');
// let readStream = request(option)
// readStream.pipe(writeStream);
// readStream.on('end', function() {
//     console.log('文件下载成功');
// });
// readStream.on('error', function(err) {
//     console.log("错误信息:" + err)
// })
// writeStream.on("finish", function() {
//     console.log("文件写入成功");
//     writeStream.end();
// });
function mkdirsSync(dirname) {
    if (fs.existsSync(dirname)) {
      return true;
    } else {
      if (mkdirsSync(path.dirname(dirname))) {
        fs.mkdirSync(dirname);
        return true;
      }
    }
  }