package main

import (
	"bufio"
	"fmt"
	"io/ioutil"
	"net"
	"os"
	"strconv"
	"strings"
)

// TCP4Server will open listeners and create Go Handlers
func TCP4Server(port int) {
	service := "127.0.0.1:" + strconv.Itoa(port)
	fmt.Printf("Trying to server on %s\n\n", service)

	listener, err := net.Listen("tcp4", service)
	checkError(err)
	defer listener.Close()
	for {
		c, err := listener.Accept()
		checkError(err)
		go ServerHandler(c)
	}

}

// ServerHandler will receive data from the socket and answer to it
func ServerHandler(c net.Conn) {

	for {

		r := bufio.NewReader(c)
		aux, err := r.ReadString('\n')
		checkError(err)
		result := strings.TrimSpace(aux)
		fmt.Println(string(result))

		answer := OpenRequestIPV4(result, 80)

		c.Write([]byte(answer))
	}

	c.Close()

}

// OpenRequestIPV4 Opens a request to an ipv4 tcp network address
func OpenRequestIPV4(ipv4Address string, port int) string {

	service := ipv4Address + ":" + strconv.Itoa(port)
	tcpv4Addr, _ := net.ResolveTCPAddr("tcp", service)
	conn, _ := net.DialTCP("tcp4", nil, tcpv4Addr)
	_, _ = conn.Write([]byte("HEAD / HTTP/1.0\r\n\r\nGet index.html"))

	result, _ := ioutil.ReadAll(conn)

	return string(result)

}

func checkError(err error) {
	if err != nil {
		fmt.Println(err.Error())
		os.Exit(1)
	}
}

func main() {
	/*if len(os.Args) != 3 {
		fmt.Println("usage: %s ip-address\n", os.Args[0])
		os.Exit(1)
	}*/

	//port, _ := strconv.Atoi(os.Args[2])
	//OpenRequestIPV4(os.Args[1], port)

	TCP4Server(15232)

}