Remove lobby.drawer as it can be inferred from player states

This leaves us with one field less that we have to keep consistent.
This will cost us some more CPU cycles, but is worth it.

internal/game/data.go

@@ -35,8 +35,6 @@ type Lobby struct {
 
 	// Whether the game has started, is ongoing or already over.
 	State State
-	// drawer references the Player that is currently drawing.
-	drawer *Player
 	// Owner references the Player that currently owns the lobby.
 	// Meaning this player has rights to restart or change certain settings.
 	Owner *Player

internal/game/lobby.go

@@ -163,7 +163,7 @@ func (lobby *Lobby) HandleEvent(eventType string, payload []byte, player *Player
 			return fmt.Errorf("word choice was %d, but should've been >= 0 and < %d", chosenIndex, len(lobby.wordChoice))
 		}
 
-		if player == lobby.drawer {
+		if player.State == Drawing {
 			lobby.selectWord(chosenIndex)
 
 			wordHintData := &Event{Type: EventTypeUpdateWordHint, Data: lobby.wordHints}
@@ -479,7 +479,7 @@ func kickPlayer(lobby *Lobby, playerToKick *Player, playerToKickIndex int) {
 		}
 	}
 
-	if lobby.drawer == playerToKick {
+	if playerToKick.State == Drawing {
 		newDrawer, roundOver := determineNextDrawer(lobby)
 		lobby.players = append(lobby.players[:playerToKickIndex], lobby.players[playerToKickIndex+1:]...)
 		lobby.Broadcast(&EventTypeOnly{Type: EventTypeDrawerKicked})
@@ -491,7 +491,6 @@ func kickPlayer(lobby *Lobby, playerToKick *Player, playerToKickIndex int) {
 			otherPlayer.LastScore = 0
 		}
 		lobby.scoreEarnedByGuessers = 0
-		lobby.drawer = nil
 
 		advanceLobbyPredefineDrawer(lobby, roundOver, newDrawer)
 	} else {
@@ -508,6 +507,15 @@ func kickPlayer(lobby *Lobby, playerToKick *Player, playerToKickIndex int) {
 	}
 }
 
+func (lobby *Lobby) Drawer() *Player {
+	for _, player := range lobby.players {
+		if player.State == Drawing {
+			return player
+		}
+	}
+	return nil
+}
+
 func calculateVotesNeededToKick(playerToKick *Player, lobby *Lobby) int {
 	connectedPlayerCount := lobby.GetConnectedPlayerCount()
 
@@ -569,14 +577,14 @@ func advanceLobbyPredefineDrawer(lobby *Lobby, roundOver bool, newDrawer *Player
 	}
 
 	// The drawer can potentially be null if kicked or the game just started.
-	if lobby.drawer != nil {
+	if drawer := lobby.Drawer(); drawer != nil {
 		if lobby.scoreEarnedByGuessers <= 0 {
-			lobby.drawer.LastScore = 0
+			drawer.LastScore = 0
 		} else {
 			// Average score, but minus one player, since the own score is 0 and doesn't count.
 			playerCount := lobby.GetConnectedPlayerCount()
 			// If the drawer isn't connected though, we mustn't subtract from the count.
-			if lobby.drawer.Connected {
+			if drawer.Connected {
 				playerCount--
 			}
 
@@ -585,8 +593,8 @@ func advanceLobbyPredefineDrawer(lobby *Lobby, roundOver bool, newDrawer *Player
 				averageScore = lobby.scoreEarnedByGuessers / playerCount
 			}
 
-			lobby.drawer.LastScore = averageScore
-			lobby.drawer.Score += lobby.drawer.LastScore
+			drawer.LastScore = averageScore
+			drawer.Score += drawer.LastScore
 		}
 	}
 
@@ -617,7 +625,6 @@ func advanceLobbyPredefineDrawer(lobby *Lobby, roundOver bool, newDrawer *Player
 	if roundOver {
 		// Game over
 		if lobby.Round == lobby.Rounds {
-			lobby.drawer = nil
 			lobby.State = GameOver
 
 			for _, player := range lobby.players {
@@ -643,8 +650,7 @@ func advanceLobbyPredefineDrawer(lobby *Lobby, roundOver bool, newDrawer *Player
 	}
 
 	lobby.ClearDrawing()
-	lobby.drawer = newDrawer
-	lobby.drawer.State = Drawing
+	newDrawer.State = Drawing
 	lobby.State = Ongoing
 	lobby.wordChoice = GetRandomWords(3, lobby)
 
@@ -663,7 +669,7 @@ func advanceLobbyPredefineDrawer(lobby *Lobby, roundOver bool, newDrawer *Player
 		},
 	})
 
-	lobby.WriteObject(lobby.drawer, &Event{Type: EventTypeYourTurn, Data: lobby.wordChoice})
+	lobby.WriteObject(newDrawer, &Event{Type: EventTypeYourTurn, Data: lobby.wordChoice})
 }
 
 // advanceLobby will either start the game or jump over to the next turn.
@@ -677,7 +683,7 @@ func advanceLobby(lobby *Lobby) {
 // is over.
 func determineNextDrawer(lobby *Lobby) (*Player, bool) {
 	for index, player := range lobby.players {
-		if player == lobby.drawer {
+		if player.State == Drawing {
 			// If we have someone that's drawing, take the next one
 			for i := index + 1; i < len(lobby.players); i++ {
 				player := lobby.players[i]
@@ -957,8 +963,8 @@ func (lobby *Lobby) OnPlayerConnectUnsynchronized(player *Player) {
 	// This state is reached if the player reconnects before having chosen a word.
 	// This can happen if the player refreshes his browser page or the socket
 	// loses connection and reconnects quickly.
-	if lobby.drawer == player && lobby.CurrentWord == "" {
-		lobby.WriteObject(lobby.drawer, &Event{Type: EventTypeYourTurn, Data: lobby.wordChoice})
+	if player.State == Drawing && lobby.CurrentWord == "" {
+		lobby.WriteObject(player, &Event{Type: EventTypeYourTurn, Data: lobby.wordChoice})
 	}
 
 	// The player that just joined already has the most up-to-date data due
@@ -1020,7 +1026,7 @@ func (lobby *Lobby) JoinPlayer(playerName string) *Player {
 }
 
 func (lobby *Lobby) canDraw(player *Player) bool {
-	return lobby.drawer == player && lobby.CurrentWord != ""
+	return player.State == Drawing && lobby.CurrentWord != "" && lobby.State == Ongoing
 }
 
 var connectionCharacterReplacer = strings.NewReplacer(" ", "", "-", "", "_", "")

internal/game/lobby_test.go

@@ -324,35 +324,35 @@ func Test_kickDrawer(t *testing.T) {
 		t.Errorf("Couldn't start lobby: %s", err)
 	}
 
-	if lobby.drawer == nil {
+	if lobby.Drawer() == nil {
 		t.Error("Drawer should've been a, but was nil")
 	}
 
-	if lobby.drawer != marcel {
-		t.Errorf("Drawer should've been a, but was %s", lobby.drawer.Name)
+	if lobby.Drawer() != marcel {
+		t.Errorf("Drawer should've been a, but was %s", lobby.Drawer().Name)
 	}
 
 	lobby.Synchronized(func() {
 		advanceLobby(lobby)
 	})
 
-	if lobby.drawer == nil {
+	if lobby.Drawer() == nil {
 		t.Error("Drawer should've been b, but was nil")
 	}
 
-	if lobby.drawer != kevin {
-		t.Errorf("Drawer should've been b, but was %s", lobby.drawer.Name)
+	if lobby.Drawer() != kevin {
+		t.Errorf("Drawer should've been b, but was %s", lobby.Drawer().Name)
 	}
 
 	lobby.Synchronized(func() {
 		kickPlayer(lobby, kevin, 1)
 	})
 
-	if lobby.drawer == nil {
+	if lobby.Drawer() == nil {
 		t.Error("Drawer should've been c, but was nil")
 	}
 
-	if lobby.drawer != chantal {
-		t.Errorf("Drawer should've been c, but was %s", lobby.drawer.Name)
+	if lobby.Drawer() != chantal {
+		t.Errorf("Drawer should've been c, but was %s", lobby.Drawer().Name)
 	}
 }