const http = require("http");
const { URL } = require("url");

let map = new Map();
map.set("get", {})
map.set("post", {})
let port = 3000
let hostName = "127.0.0.1"


let server = http.createServer()

server.listen(port, hostName, () => {
  console.log(`app is run http://${hostName}:${port}`);
})


server.get = (path, callback) => {
  map.get("get")[path] = callback
}

server.post = (path, callback) => {
  map.get("post")[path] = callback
}

server.on("request", async (req, res) => {
  if (req.url != "/favicon.ico") {
    json(res)

    // 请求方式转小写
    req.method = req.method.toLowerCase()
    // 解析请求地址
    req.url = new URL(req.url, `http://${req.headers.host}`)

    await handleReqParams(req)

    var pathName = req.url.pathname;
    if (map.get(req.method)[pathName] != undefined) {
      await map.get(req.method)[pathName](req, res)
    } else {
      // 如果请求不存在的话
      res.end(`${req.method} methods to path: ${pathName} not found`)
    }
  }

})

/**
 * 直接响应json数据
 * @param {*} res 
 */
const json = (res) => {
  res.json = (data) => res.end(JSON.stringify(data))
}

/**
 * GET请求参数转对象
 * @param {*} req 
 */
const handleReqParams = (req) => {
  return new Promise((resolve, reject) => {
    req.query = {}
    req.body = {}

    switch (req.method) {
      case "get":
        // 如果地址后面没有参数，则处理参数
        if (req.url.search.length != 0) {
          req.query = stringToObj(req.url.searchParams.toString())
        }
        resolve(req)
        break;

      case "post":
        req.on('data', (data) => req.body = JSON.parse(data.toString()));
        req.on('end', () => resolve(req))
        break;

      default:
        break;
    }
  })
}

function stringToObj(str) {
  var obj = {};
  var temp = str.split('&')
  for (var i = 0; i < temp.length; i++) {
    var t = temp[i].split('=')
    obj[t[0]] = Number.isNaN(Number(t[1])) ? decodeURIComponent(t[1]) : Number(t[1])
  }
  return obj
}

module.exports = server