cloud-game/handler/room/room.go

package room

import (
	"fmt"
	"image"
	"io/ioutil"
	"log"
	"math/rand"
	"os"
	"strconv"
	"sync"

	emulator "github.com/giongto35/cloud-game/emulator"
	storage "github.com/giongto35/cloud-game/handler/cloud-storage"
	"github.com/giongto35/cloud-game/webrtc"
)

// Room is a game session. multi webRTC sessions can connect to a same game.
// A room stores all the channel for interaction between all webRTCs session and emulator
type Room struct {
	ID string

	imageChannel chan *image.RGBA
	audioChannel chan float32
	inputChannel chan int
	// Done channel is to fire exit event when there is no webRTC session running
	Done bool

	rtcSessions  []*webrtc.WebRTC
	sessionsLock *sync.Mutex

	director *emulator.Director

	// Cloud storage to store room state online
	onlineStorage *storage.Client
}

// NewRoom creates a new room
func NewRoom(roomID, gamepath, gameName string, onlineStorage *storage.Client) *Room {
	// if no roomID is given, generate it
	if roomID == "" {
		roomID = generateRoomID()
	}
	log.Println("Init new room", roomID, gameName)
	imageChannel := make(chan *image.RGBA, 100)
	audioChannel := make(chan float32, emulator.SampleRate)
	inputChannel := make(chan int, 100)

	// create director
	director := emulator.NewDirector(roomID, imageChannel, audioChannel, inputChannel)

	room := &Room{
		ID: roomID,

		imageChannel:  imageChannel,
		audioChannel:  audioChannel,
		inputChannel:  inputChannel,
		rtcSessions:   []*webrtc.WebRTC{},
		sessionsLock:  &sync.Mutex{},
		director:      director,
		Done:          false,
		onlineStorage: onlineStorage,
	}

	go room.startVideo()
	go room.startAudio()

	// Check if room is on local storage, if not, pull from GCS to local storage
	path := gamepath + "/" + gameName
	go func(path, roomID string) {
		// Check room is on local or fetch from server
		savepath := emulator.GetSavePath(roomID)
		log.Println("Check ", savepath, " on local : ", room.isGameOnLocal(savepath))
		if !room.isGameOnLocal(savepath) {
			// Fetch room from GCP to server
			log.Println("Load room from online storage", savepath)
			if err := room.saveOnlineRoomToLocal(roomID, savepath); err != nil {
				log.Printf("Warn: Room %s is not in online storage, error %s", roomID, err)
			}
		}

		log.Printf("Room %s started", roomID)
		director.Start([]string{path})
		log.Printf("Room %s ended", roomID)
	}(path, roomID)

	return room
}

// generateRoomID generate a unique room ID containing 16 digits
func generateRoomID() string {
	roomID := strconv.FormatInt(rand.Int63(), 16)
	log.Println("Generate Room ID", roomID)
	//roomID := uuid.Must(uuid.NewV4()).String()
	return roomID
}

func (r *Room) isGameOnLocal(savepath string) bool {
	_, err := os.Open(savepath)
	return err == nil
}

func (r *Room) AddConnectionToRoom(peerconnection *webrtc.WebRTC, playerIndex int) {
	peerconnection.AttachRoomID(r.ID)
	r.rtcSessions = append(r.rtcSessions, peerconnection)

	go r.startWebRTCSession(peerconnection, playerIndex)
}

func (r *Room) startWebRTCSession(peerconnection *webrtc.WebRTC, playerIndex int) {
	defer func() {
		if r := recover(); r != nil {
			fmt.Println("Recovered when sent to close inputChannel")
		}
	}()

	go func() {
		for {
			input, ok := <-peerconnection.InputChannel
			if !ok {
				return
				// might consider continue here
			}

			if peerconnection.Done || !peerconnection.IsConnected() || r.Done {
				return
			}

			if peerconnection.IsConnected() {
				// the first 8 bits belong to player 1
				// the next 8 belongs to player 2 ...
				// We standardize and put it to inputChannel (16 bits)
				input = input << ((uint(playerIndex) - 1) * emulator.NumKeys)
				select {
				case r.inputChannel <- input:
				default:
				}
			}
		}
	}()

	log.Println("Peerconn done")
}

func (r *Room) CleanSession(peerconnection *webrtc.WebRTC) {
	r.removeSession(peerconnection)
}

func (r *Room) removeSession(w *webrtc.WebRTC) {
	fmt.Println("Cleaning session: ", w)
	fmt.Println("Sessions list", r.rtcSessions)
	// TODO: get list of r.rtcSessions in lock
	for i, s := range r.rtcSessions {
		fmt.Println("found session: ", s, w)
		if s.ID == w.ID {
			r.rtcSessions = append(r.rtcSessions[:i], r.rtcSessions[i+1:]...)
			fmt.Println("found session: ", len(r.rtcSessions))

			// If room has no sessions, close room
			// Note: this logic cannot be brought outside of forloop because we only close room if room had at least one session
			if len(r.rtcSessions) == 0 {
				log.Println("No session in room")
				r.Close()
				// can consider sanding close to room and room do clean
				//close(r.Done)
			}
			break
		}
	}
}

func (r *Room) Close() {
	if r.Done {
		return
	}

	log.Println("Closing room", r.ID)
	log.Println("Closing director of room ", r.ID)
	close(r.director.Done)
	log.Println("Closing input of room ", r.ID)
	close(r.inputChannel)
	r.Done = true
	// Close here is a bit wrong because this read channel
	//close(r.imageChannel)
	//close(r.audioChannel)
}

func (r *Room) SaveGame() error {
	onlineSaveFunc := func() error {
		// Try to save the game to gCloud
		if err := r.onlineStorage.SaveFile(r.ID, r.director.GetHashPath()); err != nil {
			return err
		}

		return nil
	}

	// TODO: Move to game view
	if err := r.director.SaveGame(onlineSaveFunc); err != nil {
		return err
	}

	return nil
}

func (r *Room) saveOnlineRoomToLocal(roomID string, savepath string) error {
	log.Println("Try loading game from cloud storage")
	// If the game is not on local server
	// Try to load from gcloud
	data, err := r.onlineStorage.LoadFile(roomID)
	if err != nil {
		return err
	}
	// Save the data fetched from gcloud to local server
	ioutil.WriteFile(savepath, data, 0644)

	return nil
}

func (r *Room) LoadGame() error {
	err := r.director.LoadGame()

	return err
}

func (r *Room) IsRunning() bool {
	// If there is running session
	for _, s := range r.rtcSessions {
		if s.IsConnected() {
			return true
		}
	}

	return false
}