mini-chat/cmd/server.go

/*
Copyright © 2024 Raul
*/

package cmd

import (
	"bufio"
	"fmt"
	"github.com/spf13/cobra"
	"net"
	"strings"
	"time"
)

// serverCmd represents the server command
var serverCmd = &cobra.Command{
	Use:   "server",
	Short: "Main chat server",
	Long: `You can connect to this server by running the following command from
a client:
	nc $SERVER_IP $PORT

Assuming your IP is 192.168.0.30 and the server port is left on default the
command would be as follows:
	nc 192.168.0.30 1302`,
	Run: func(cmd *cobra.Command, args []string) {
		server(cmd)
	},
}

func init() {
	rootCmd.AddCommand(serverCmd)

	// Here you will define your flags and configuration settings.

	// Cobra supports Persistent Flags which will work for this command
	// and all subcommands, e.g.:
	// serverCmd.PersistentFlags().String("foo", "", "A help for foo")

	// Cobra supports local flags which will only run when this command
	// is called directly, e.g.:
	// serverCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
	serverCmd.Flags().String("port", "1302", "Port to listen on")
}

var receiverIsStarted bool = false

type chatter struct {
	Username string
	IP       string
}

func server(cmd *cobra.Command) {
	var lport string
	port, _ := cmd.Flags().GetString("port")
	if port != "" {
		lport = port
	} else {
		lport = "1302"
	}

	ln, err := net.Listen("tcp", ":"+lport)
	cobra.CheckErr(err)
	fmt.Printf("Listening on port %v...\n", lport)
	masterChannel := make(chan string, 20)

	slaveChannel := make(chan string, 20)
	go masterReceiver(slaveChannel, masterChannel)
	// TODO: get channels properly working
	// receivingChannel := make(chan string)
	// sendingChannel := make(chan string)
	for {
		conn, err := ln.Accept()
		cobra.CheckErr(err)
		numOfClients++
		go handleConn(conn, slaveChannel, masterChannel)
	}

}

var numOfClients int = 0

func masterReceiver(slaveChannel chan<- string, masterChannel <-chan string) {
	for {
		message := <-masterChannel
		for i := 0; i < numOfClients; i++ {
			slaveChannel <- message
		}
	}
}

// func receiver(conn net.Conn, ch chan string) {
// 	fmt.Println("THE RECEIVER HAS BEEN STARTED, YOU CAN ONLY SEE THIS MESSAGE ONCE")
// 	receiverIsStarted = false
// 	for {
// 		select {
// 		case otherMessage := <-ch:
// 			conn.Write([]byte(otherMessage))
// 		default:
// 		}
// 	}
// }

func handleConn(conn net.Conn, slaveChannel <-chan string, masterChannel chan<- string) {
	defer conn.Close()
	//var otherMessage string

	go func() {
		for {
			//select {
			message := <-slaveChannel
			conn.Write([]byte(message))
		}
	}()

	IP := getIP(conn)
	t := time.Now()
	date := fmt.Sprintf("%d-%02d-%02d | %02d:%02d:%02d", t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second())
	final_message_connect := fmt.Sprintf("[%v] Received connection from %v!\n", date, IP)
	fmt.Print(final_message_connect)
	conn.Write([]byte("What's your name?\nName: "))
	name, err := bufio.NewReader(conn).ReadString('\n')
	if err != nil {
		numOfClients--
		return
	}
	var NewUser = new(chatter)
	NewUser.Username = strings.TrimRight(name, "\n")
	NewUser.IP = IP
	for {
		message, err := bufio.NewReader(conn).ReadString('\n')
		if err != nil {
			fmt.Printf(NewUser.Username + " disconnected!\n")
			numOfClients--
			return
		}
		finalMessage := fmt.Sprint("{" + NewUser.IP + "} " + NewUser.Username + ": " + message)
		fmt.Print(finalMessage)
		masterChannel <- finalMessage
		//conn.Write([]byte(message))
	}
}

func getIP(conn net.Conn) (IP string) {
	if addr, ok := conn.RemoteAddr().(*net.TCPAddr); ok {
		IP = fmt.Sprintf("%v", addr)
	}
	return IP
}