Implement ClientJoinGame packet handling

Author: Swan

handlers/ClientJoinGame.go

@@ -0,0 +1,23 @@
+package handlers
+
+import (
+	"example.com/Quaver/Z/multiplayer"
+	"example.com/Quaver/Z/packets"
+	"example.com/Quaver/Z/sessions"
+)
+
+// Handles when a user attempts to join a game
+func handleClientJoinGame(user *sessions.User, packet *packets.ClientJoinGame) {
+	if packet == nil {
+		return
+	}
+
+	game := multiplayer.GetGameByIdString(packet.GameId)
+
+	if game == nil {
+		sessions.SendPacketToUser(packets.NewServerJoinGameFailed(packets.JoinGameErrorMatchNoExists), user)
+		return
+	}
+
+	game.AddPlayer(user.Info.Id, packet.Password)
+}

handlers/packets.go

@@ -48,6 +48,8 @@ func HandleIncomingPackets(conn net.Conn, msg string) {
 		handleClientCreateGame(user, unmarshalPacket[packets.ClientCreateGame](msg))
 	case packets.PacketIdClientLeaveGame:
 		handleClientLeaveGame(user, unmarshalPacket[packets.ClientLeaveGame](msg))
+	case packets.PacketIdClientJoinGame:
+		handleClientJoinGame(user, unmarshalPacket[packets.ClientJoinGame](msg))
 	default:
 		log.Println(fmt.Errorf("unknown packet: %v", msg))
 	}

multiplayer/game.go

@@ -58,6 +58,12 @@ func (game *Game) AddPlayer(userId int, password string) {
 		return
 	}
 
+	currentGame := GetGameById(user.GetMultiplayerGameId())
+
+	if currentGame != nil && currentGame.Data.Id != game.Data.Id {
+		currentGame.RemovePlayer(user.Info.Id)
+	}
+
 	if len(game.Data.PlayerIds) >= maxPlayerCount {
 		sessions.SendPacketToUser(packets.NewServerJoinGameFailed(packets.JoinGameErrorFull), user)
 		return

multiplayer/lobby.go

@@ -80,6 +80,20 @@ func GetGameById(id int) *Game {
 	return lobby.games[id]
 }
 
+// GetGameByIdString Retrieves a game by its stringified id
+func GetGameByIdString(id string) *Game {
+	lobby.mutex.Lock()
+	defer lobby.mutex.Unlock()
+
+	for _, game := range lobby.games {
+		if game.Data.GameId == id {
+			return game
+		}
+	}
+
+	return nil
+}
+
 // SendLobbyUsersGameInfoPacket Sends all the users in the lobby a packet with game information
 // Be careful of deadlocks when calling this. Make sure not to call the mutex twice.
 func sendLobbyUsersGameInfoPacket(game *Game, lock bool) {

packets/ClientJoinGame.go

@@ -0,0 +1,7 @@
+package packets
+
+type ClientJoinGame struct {
+	Packet
+	GameId   string `json:"gid"`
+	Password string `json:"p"`
+}