main.go

package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"github.com/RoboCup-SSL/ssl-game-controller/pkg/refproto"
	"github.com/golang/protobuf/proto"
	"log"
	"math"
	"net"
	"time"
)

const maxDatagramSize = 8192

var refereeAddress = flag.String("address", "224.5.23.1:10003", "The multicast address of ssl-game-controller")
var fullScreen = flag.Bool("fullScreen", false, "Print the formatted message to the console, clearing the screen during print")

var history []refproto.Referee_Command

func main() {
	flag.Parse()

	addr, err := net.ResolveUDPAddr("udp", *refereeAddress)
	if err != nil {
		log.Fatal(err)
	}
	conn, err := net.ListenMulticastUDP("udp", nil, addr)
	if err != nil {
		log.Fatal(err)
	}

	if err := conn.SetReadBuffer(maxDatagramSize); err != nil {
		log.Printf("Could not set read buffer to %v.", maxDatagramSize)
	}
	log.Println("Receiving from", *refereeAddress)

	b := make([]byte, maxDatagramSize)
	for {
		n, err := conn.Read(b)
		if err != nil {
			log.Print("Could not read", err)
			time.Sleep(1 * time.Second)
			continue
		}
		if n >= maxDatagramSize {
			log.Fatal("Buffer size too small")
		}
		refMsg := refproto.Referee{}
		if err := proto.Unmarshal(b[0:n], &refMsg); err != nil {
			log.Println("Could not unmarshal referee message")
			continue
		}
		if len(history) == 0 || *refMsg.Command != history[len(history)-1] {
			history = append(history, *refMsg.Command)
		}

		if *fullScreen {
			// clear screen, move cursor to upper left corner
			fmt.Print("\033[H\033[2J")

			// print last commands
			fmt.Print("Last commands: ")
			n := int(math.Min(float64(len(history)), 5.0))
			for i := 0; i < n; i++ {
				fmt.Print(history[len(history)-1-i])
				if i != n-1 {
					fmt.Print(",")
				}
			}
			fmt.Println()
			fmt.Println()

			// print message formatted with line breaks
			fmt.Print(proto.MarshalTextString(&refMsg))
		} else {
			b, err := json.Marshal(refMsg)
			if err != nil {
				log.Fatal(err)
			}
			log.Print(string(b))
		}
	}
}