package main

import "os"
import "io"
import "fmt"
import "log"
import "errors"
import "git.tebibyte.media/sashakoshka/hopp"
import "git.tebibyte.media/sashakoshka/hopp/examples/ping"

func main() {
	name := os.Args[0]
	if len(os.Args) != 2 {
		fmt.Fprintf(os.Stderr, "Usage: %s HOST:PORT\n", name)
		os.Exit(2)
	}
	address  := os.Args[1]
	err := listen(address)
	handleErr(1, err)
}

func listen(address string) error {
	listener, err := hopp.Listen("tcp", address, nil)
	if err != nil { return err }
	log.Printf("(i) hosting on %s", address)
	for {
		conn, err := listener.Accept()
		if err != nil { return err }
		go run(conn)
	}
}

func run(conn hopp.Conn) {
	log.Printf("-=E %v connected", conn.RemoteAddr())
	defer log.Printf("X=- %v disconnected", conn.RemoteAddr())
	defer conn.Close()
	
	for {
		trans, err := conn.AcceptTrans()
		if err != nil {
			if !errors.Is(err, io.EOF) {
				log.Printf("XXX %v failed: %v", conn.RemoteAddr(), err)
			}
			return
		}
		go runTrans(conn, trans)
	}
}

func runTrans(conn hopp.Conn, trans hopp.Trans) {
	for {
		message, _, err := ping.Receive(trans)
		if err != nil {
			if !errors.Is(err, io.EOF) {
				log.Printf("XXX failed to receive message: %v", err)
			}
			return
		}
		switch message := message.(type) {
		case *ping.MessagePing:
			log.Printf("--> ping (%d) from %v", message, conn.RemoteAddr())
			response := ping.MessagePong(*message)
			_, err := ping.Send(trans, &response)
			if err != nil {
				log.Printf("XXX failed to send message: %v", err)
				return
			}
		}
	}
}

func handleErr(code int, err error) {
	if err != nil {
		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
		os.Exit(code)
	}
}