package main

import (
  "bytes"
  "fmt"
  "net"
  "os"
  "strconv"
)

const (
  CONN_HOST = ""
  CONN_PORT = "3333"
  CONN_TYPE = "tcp"
)

func main() {
  // Listen for incoming connections.
  l, err := net.Listen(CONN_TYPE, ":"+CONN_PORT)
  if err != nil {
    fmt.Println("Error listening:", err.Error())
    os.Exit(1)
  }
  // Close the listener when the application closes.
  defer l.Close()
  fmt.Println("Listening on " + CONN_HOST + ":" + CONN_PORT)
  for {
    // Listen for an incoming connection.
    conn, err := l.Accept()
    if err != nil {
      fmt.Println("Error accepting: ", err.Error())
      os.Exit(1)
    }

    //logs an incoming message
    fmt.Printf("Received message %s -> %s \n", conn.RemoteAddr(), conn.LocalAddr())

    // Handle connections in a new goroutine.
    go handleRequest(conn)
  }
}

// Handles incoming requests.
func handleRequest(conn net.Conn) {
  // Make a buffer to hold incoming data.
  buf := make([]byte, 1024)
  // Read the incoming connection into the buffer.
  reqLen, err := conn.Read(buf)
  if err != nil {
    fmt.Println("Error reading:", err.Error())
  }
  // Builds the message.
  message := "Hi, I received your message! It was "
  message += strconv.Itoa(reqLen)
  message += " bytes long and that's what it said: \""
  n := bytes.Index(buf, []byte{0})
  message += string(buf[:n-1])
  message += "\" ! Honestly I have no clue about what to do with your messages, so Bye Bye!\n"

  // Write the message in the connection channel.
  conn.Write([]byte(message))
  // Close the connection when you're done with it.
  conn.Close()
}