const https = require("https");
const http = require("http");
const fs = require("fs");

let fileCount = 0;

function add() {
  fileCount++;
  console.log(fileCount);
}

const browser = {
  "User-Agent":
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36",
};

function queryByPage(page = 1) {
  const req = https.request(
    `https://www.doutula.com/article/list/?page=${page}`,
    {
      method: "GET",
      "user-agent":
        "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36",
      // 拒绝301
      allow_redirects: false,
    },
    (resq) => {
      console.log(`${page} status CODE:`, resq.statusCode);
      let data = "";
      resq.on("data", (chunk) => {
        data = `${data}${chunk}`;
        // console.log(`响应主体: ${chunk}`);
      });
      resq.on("end", () => {
        const imgSrc = getImgUrlFormDocument(data, "data-original");
        imgSrc.forEach((item) => {
          if (item) {
            const imgurl = item.slice(15, -1);
            const isHttps = /^http/.test(imgurl);
            getImg(
              isHttps ? imgurl : "https:" + imgurl,
              `./Biaoqing/第${page}页`
            );
          }
        });
      });
    }
  );
  req.end();
}

function getImg(url, saveLoaclPath = "./新建文件夹") {
  const imgUrl = url.split("/");
  const imgDefaultName = imgUrl[imgUrl.length - 1];

  // 图片请求写入本地
  let imgData = "";

  const imgRequest = http.get(url, browser, function (req) {
    // console.log("img request STATUS CODE:".req.statusCode);
    // 改变编码以保存图片
    req.setEncoding("binary");

    req.on("data", function (chunk) {
      imgData += chunk;
    });

    req.on("end", function () {
      fs.mkdir(saveLoaclPath, { recursive: true }, function () {
        fs.writeFile(
          saveLoaclPath + "/" + imgDefaultName,
          imgData,
          "binary",
          function (err) {
            add();
            if (err) {
              return console.log(err);
            }
            console.log(
              `${saveLoaclPath.slice(2)}/${imgDefaultName} save success !!!`
            );
          }
        );
      });
    });
  });

  imgRequest.end();
}

/**
 * 从文档中解析img路径
 */
function getImgUrlFormDocument(document, imgProps = "src") {
  const img = document.match(/(<img.*?)>/g);
  if (imgProps === "img") {
    return img;
  }

  const imgUrlProps = new RegExp(`(${imgProps}=['"].*?)['"]`, "g");
  return img.map(
    (item) => item.match(imgUrlProps) && item.match(imgUrlProps)[0]
  );
}

/**
 * 创建请求
 */
Array.from({ length: 2 }).forEach((item, index) => {
  queryByPage(index + 1);
});

process.on("uncaughtException", function (err) {
  console.log("Caught exception: " + err);
});