package main

import (
	"bufio"
	"fmt"
	"net"
	"time"
)

type Client struct {
	conn net.Conn
}

func (c *Client) Write(content string) error {
	_, err := c.conn.Write([]byte(content + "\n"))

	return err
}

func (c *Client) Read() (string, error) {
	reader := bufio.NewReader(c.conn)

	return reader.ReadString('\n')
}

func (c *Client) Close() error {
	return c.conn.Close()
}

// create tcp client
func getClient(address string) (*Client, error) {
	// try to resolve address
	_, err := net.ResolveTCPAddr("tcp", address)

	if err != nil {
		return nil, err
	}

	// create tcp connection with 5s timeout 
	conn, err := net.DialTimeout("tcp", address, 5*time.Second)

	if err != nil {
		return nil, err
	}

	conn.SetReadDeadline(time.Now().Add(5 * time.Second))
	conn.SetWriteDeadline(time.Now().Add(5 * time.Second))

	return &Client{conn: conn}, nil
}

func main() {
	// see https://tcpbin.com/
	client, err := getClient("tcpbin.com:4242")

	if err != nil {
		panic(err)
	}

	// close the connection at the end
	defer client.Close()

	// send request to tcpbin.com echo server
	err = client.Write("Hello, World!!!")

	if err != nil {
		panic(err)
	}

	// read response from tcpbin.com echo server
	content, err := client.Read()

	if err != nil {
		panic(err)
	}

	fmt.Print(content)
}

// $ go run main.go 
// Hello, World!!!