app.js

const fs = require('fs')
const http = require('http')

const server = http.createServer((request, response) =>{

  const url = new URL(request.url, "http://${request.headers.host}")

  switch(url.pathname){
    case '/':
      if(request.method === 'GET'){
        // Extract piece of query from url.
        const name = url.searchParams.get('name')
        response.writeHead(200, {
          'Content-Type': 'text/html'
        })
        // Read index as stream and save it in response.
        fs.createReadStream("index.html").pipe(response)
      } else if (request.method === 'POST'){
          handlePostResponse(request, response)
      }
    break
      
    default:
      response.writeHead(404, {'Content-Type': 'text/html'})
      fs.createReadStream("404.html").pipe(response)
    break
  }
})

server.listen(4001, ()=>{
  console.log("Server listening on " + server.address().port)
})



// Function for handling POST responses
function handlePostResponse(request, response){
  request.setEncoding('utf8')
  
  // Receive chunks on 'data' event and concatenate to body variable
  let body = ''
  request.on('data', function (chunk) {
    body += chunk
  })
  
  // When done receiving data, select a random choice for server
  // Compare server choice with player's choice and send an appropriate message back
  request.on('end', function () {
    const choices = ['rock', 'paper', 'scissors']
    const randomChoice = choices[Math.floor(Math.random() * 3)]

    const choice = body

    let message

    const tied = `Aww, we tied! I also chose ${randomChoice}.`
    const victory = `Dang it, you won! I chose ${randomChoice}.`
    const defeat = `Ha! You lost. I chose ${randomChoice}.`

    if (choice === randomChoice) {
      message = tied
    } else if (
        (choice === 'rock' && randomChoice === 'paper') ||
        (choice === 'paper' && randomChoice === 'scissors') ||
        (choice === 'scissors' && randomChoice === 'rock')
    ) {
      message = defeat
    } else {
      message = victory
    }
    response.writeHead(200, { 'Content-Type': 'text/plain' })
    response.end(`You selected ${choice}. ${message}`)
  })
}