refactor: improve multiplayer connection lifecycle

* Move client/server connection handling into game-specific networking classes
* Add multiplayer data reset for disconnected clients
* Clean up invalid MessageBus listeners after disconnects
* Persist lobby host address and port in game data
* Standardize the default server port to 8080
* Increase server address input length to support valid addresses
* Remove obsolete connection and match initialization logic from base networking

game_client.gd

@@ -10,11 +10,18 @@ func setup_signals() -> void:
 
 	MessageBus.subscribe("game_wait_for_connection", _wait_for_connection)
 	MessageBus.subscribe("game_close_connection", _wait_close_connection)
+	MessageBus.subscribe("game_peer_disconnected", _on_game_peer_disconnected)
 
 func _start_client(address: String = "127.0.0.1", port: int = 8080) -> void:
 	if peer: return
 	start_client(address, port)
 
+func _on_game_peer_disconnected() -> void:
+	close_connection()
+
+	Globals.multiplayer_data.reset()
+	Globals.lobby_data.go_back_to_match_screen()
+	MessageBus.clear_voided_listeners()
 
 func client_connected_to_server() -> void:
 	push_warning("Connected to server!")

game_server.gd

@@ -6,6 +6,26 @@ func _ready() -> void:
 
 
 func setup_signals() -> void:
-	#MessageBus.subscribe("game_wait_for_connection", _wait_for_connection)
-	#MessageBus.subscribe("game_close_connection", _wait_close_connection)
 	pass
+
+func server_client_connected(id: int) -> void:
+	push_warning("Client Connected... ID: ", id)
+
+	if not Globals.game_data.client1:
+		Globals.game_data.client1 = id
+	elif not Globals.game_data.client2:
+		Globals.game_data.client2 = id
+
+	if Globals.game_data.client1 and Globals.game_data.client2:
+		Globals.multiplayer_data.init_match()
+
+	# TODO: Add watch match feature...
+
+func server_client_disconnected(id: int) -> void:
+	push_warning("Client Disconnected... ID: ", id)
+
+	MessageBus.emit_propagation_clients_only.rpc("game_peer_disconnected", null)
+
+	await get_tree().create_timer(5.0).timeout
+	# NOTE: Quits game server instance.
+	get_tree().quit()

globals/message_bus.gd

@@ -11,6 +11,14 @@ func subscribe(id: String, callback: Callable) -> void:
 	message_types.get(id).append(callback)
 
 
+func clear_voided_listeners() -> void:
+	for mtype in message_types.keys():
+		var mlisteners: Array = message_types.get(mtype)
+		for mlistener in mlisteners:
+			if mlistener.is_valid(): continue
+			mlisteners.erase(mlistener)
+
+
 func emit_local(id: String, data: Variant, expand: bool = false) -> void:
 	emit_propagation(id, data, expand)
 

scenes/data_bridge/multiplayer_data.gd

@@ -23,8 +23,17 @@ func set_active_player_id(id: int) -> void:
 
 	current_turn_player_id = id
 
+func reset() -> void:
+	multiplayer_synchronizer                    = MultiplayerSynchronizer.new()
+	synchronizer_config                         = SceneReplicationConfig.new()
+	current_turn_player_id                      = -1
 
-func init_match():
+	is_multiplayer_active                       = true
+	multiplayer_synchronizer.name               = "multiplayer_synchronizer"
+	multiplayer_synchronizer.replication_config = synchronizer_config
+	multiplayer_synchronizer.root_path          = "/root/billiards"
+
+func init_match() -> void:
 	var match_entry = Dictionary()
 	match_entry.set("type", Globals.game_data.game_mode)
 

scenes/screens/lobby_screen/lobby_base.gd

@@ -28,7 +28,11 @@ func _on_home_bttn_pressed() -> void:
 	)
 
 func _on_host_connect_bttn_pressed() -> void:
-	client.start_client(host_address_input.text, int(host_port_range.value))
+	Globals.game_data.game_address = host_address_input.text
+	Globals.game_data.game_port    = int(host_port_range.value)
+	client.start_client(
+		Globals.game_data.game_address, Globals.game_data.game_port
+	)
 
 func _on_host_disconnect_bttn_pressed() -> void:
 	match_create_vbox.visible    = false

scenes/ui_controls/lobby_screen/lobby_ui.tscn

@@ -55,7 +55,7 @@ size_flags_horizontal = 3
 text = "127.0.0.1"
 placeholder_text = "Server Address: (Eg. 0.0.0.0)"
 alignment = 1
-max_length = 12
+max_length = 15
 emoji_menu_enabled = false
 clear_button_enabled = true
 caret_blink = true
@@ -65,7 +65,7 @@ layout_mode = 2
 min_value = 1.0
 max_value = 65535.0
 page = 10.0
-value = 31315.0
+value = 8080.0
 rounded = true
 alignment = 1
 

scripts/client_networking.gd

@@ -8,6 +8,7 @@ func start_client(address: String = "127.0.0.1", port: int = 8080) -> void:
 	if peer: return
 
 	push_warning("Client Starting... Address: ", address, " Port: ", port)
+	# TODO: Add throbber or other indication of connection attempt.
 
 	peer = ENetMultiplayerPeer.new()
 	peer.create_client(address, port)

scripts/server_networking.gd

@@ -40,30 +40,8 @@ func close_connection() -> void:
 	peer.close()
 	peer = null
 
-func server_client_connected(id: int) -> void:
-	push_warning("Client Connected... ID: ", id)
+func server_client_connected(_id: int) -> void:
+	assert(false, "This method needs to be overridden...")
 
-	if not Globals.game_data.client1:
-		Globals.game_data.client1 = id
-	elif not Globals.game_data.client2:
-		Globals.game_data.client2 = id
-
-	if Globals.game_data.client1 and Globals.game_data.client2:
-		Globals.multiplayer_data.init_match()
-
-	# TODO: Add watch match feature...
-
-func server_client_disconnected(id: int) -> void:
-	push_warning("Client Disconnected... ID: ", id)
-
-	# TODO: Fix call structure
-	#if id == Globals.game_data.client1:
-		#LobbyNetworking.rpc_id(
-			#Globals.game_data.client1,
-			#"go_back_to_match_screen"
-		#)
-	#elif id == Globals.game_data.client2:
-		#LobbyNetworking.rpc_id(
-			#Globals.game_data.client2,
-			#"go_back_to_match_screen"
-		#)
+func server_client_disconnected(_id: int) -> void:
+	assert(false, "This method needs to be overridden...")