Event Bus

eventbus/defaulteventbus.gd

@@ -0,0 +1,43 @@
+class_name DefaultEventBus
+extends EventBus
+
+var subscribers: Dictionary = {}
+
+func _init():
+	subscribers = {}
+
+func subscribers_of(event_scope: EventScope, event_type: String) -> Array[Subscription]:
+	var key = [event_scope, event_type]
+	return subscribers.get(key, [])
+
+func subscribe_to(event_scope: EventScope, event_type: String, fn: Callable) -> Subscription:
+	var key = [event_scope, event_type]
+	var subscriber_set: Array[EventBusSubscription] = subscribers.get(key, [] as Array[EventBusSubscription])
+	var subscription = EventBusSubscription.new(key, fn, self)
+	subscriber_set.append(subscription)
+	subscribers[key] = subscriber_set
+	return subscription
+
+func publish(event_scope: EventScope, event: Event) -> void:
+	var key = [event_scope, event.get_type()]
+	var subscriber_set: Array[EventBusSubscription] = subscribers.get(key, [] as Array[EventBusSubscription]).duplicate(true)
+	for subscriber in subscriber_set:
+		var result = subscriber.callback.call(event)
+		if result == EventResult.ResultType.DISPOSE_SUBSCRIPTION:
+			subscriber.dispose()
+
+func cancel_scope(event_scope: EventScope) -> void:
+	var keys_to_cancel: Array = []
+	for key in subscribers.keys():
+		if key[0] == event_scope:
+			keys_to_cancel.append(key)
+	for key in keys_to_cancel:
+		var subscriber_set: Array[EventBusSubscription] = subscribers[key]
+		for subscriber in subscriber_set:
+			subscriber.dispose()
+
+func dispose() -> void:
+	for subscriber_set in subscribers.values():
+		for subscriber in subscriber_set:
+			subscriber.dispose()
+	subscribers.clear()

eventbus/defaultscope.gd

@@ -0,0 +1,2 @@
+class_name DefaultScope
+extends EventScope

eventbus/event.gd

@@ -0,0 +1,12 @@
+class_name Event
+extends RefCounted
+
+var type: String
+var source: Variant
+
+func _init(_source: Variant = null):
+	source = _source
+	type = self.get_class()
+
+func get_type() -> String:
+	return type

eventbus/eventbus.gd

@@ -0,0 +1,17 @@
+class_name EventBus
+extends Node
+
+func subscribers_of(_event_scope: EventScope, _event_type: String) -> Array[Subscription]:
+	return Array()
+
+func subscribe_to(_event_scope: EventScope, _event_type: String, _fn: Callable) -> Subscription:
+	return Subscription.new()
+
+func publish(_event_scope: EventScope, _event: Event) -> void:
+	pass
+
+func cancel_scope(_event_scope: EventScope) -> void:
+	pass
+
+func dispose() -> void:
+	pass

eventbus/eventbussubscription.gd

@@ -0,0 +1,19 @@
+class_name EventBusSubscription
+extends Subscription
+
+var key: Array
+var callback: Callable
+var bus: DefaultEventBus
+
+func _init(_key: Array, _callback: Callable, _bus: DefaultEventBus):
+	key = _key
+	callback = _callback
+	bus = _bus
+
+func dispose() -> void:
+	var subscriber_set: Array[EventBusSubscription] = bus.subscribers.get(key, [])
+	subscriber_set.erase(self)
+	if subscriber_set.is_empty():
+		bus.subscribers.erase(key)
+	else:
+		bus.subscribers[key] = subscriber_set

eventbus/eventresult.gd

@@ -0,0 +1,7 @@
+class_name EventResult
+extends RefCounted
+
+enum ResultType {
+	KEEP_SUBSCRIPTION,
+	DISPOSE_SUBSCRIPTION
+}

eventbus/eventscope.gd

@@ -0,0 +1,2 @@
+class_name EventScope
+extends Node

eventbus/subscription.gd

@@ -0,0 +1,5 @@
+class_name Subscription
+extends RefCounted
+
+func dispose() -> void:
+	pass

input_event.gd

@@ -0,0 +1,10 @@
+class_name KeyboardInputEvent
+extends Event
+
+var action: String
+var pressed: bool
+	
+func _init(_action: String, _pressed: bool):
+	action = _action
+	pressed = _pressed
+	type = "KeyboardInputEvent"

main.gd

@@ -0,0 +1,35 @@
+extends Node
+
+func _init() -> void:
+	var node = WeaponsSystem.new()
+	node.set_name("WeaponsSystem")
+	add_child(node)
+	
+	node = DefaultEventBus.new()
+	node.set_name("MainEventBus")
+	add_child(node)
+	
+	node = EventScope.new()
+	node.set_name("InputEventScope")
+	add_child(node)
+
+# Called when the node enters the scene tree for the first time.
+func _ready() -> void:
+	pass # Replace with function body.
+
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta: float) -> void:
+	var actions = [
+		"ui_fire",
+		"ui_up",
+		"ui_down",
+		"ui_left",
+		"ui_right",
+		]
+	for action in actions:
+		if Input.is_action_pressed(action):
+			get_node("/root/Main/MainEventBus").publish(get_node("/root/Main/InputEventScope"), KeyboardInputEvent.new(action, true))
+		elif Input.is_action_just_released(action):
+			get_node("/root/Main/MainEventBus").publish(get_node("/root/Main/InputEventScope"), KeyboardInputEvent.new(action, false))
+	pass

main.tscn

@@ -1,10 +1,10 @@
 [gd_scene load_steps=13 format=3 uid="uid://8ocp10j32f62"]
 
+[ext_resource type="Script" path="res://main.gd" id="1_eedai"]
 [ext_resource type="Texture2D" uid="uid://y6phkg4twpdm" path="res://images/bg_space_seamless.png" id="1_rpyi5"]
 [ext_resource type="Texture2D" uid="uid://cran7fr1i2qou" path="res://images/spaceship-placeholder.png" id="2_f2x66"]
 [ext_resource type="Script" path="res://spaceship.gd" id="3_ttkgl"]
 [ext_resource type="Script" path="res://laser.gd" id="4_uhf7q"]
-[ext_resource type="Script" path="res://weapons_system.gd" id="5_gf6oh"]
 [ext_resource type="Script" path="res://asteroid.gd" id="6_n4dsl"]
 [ext_resource type="Texture2D" uid="uid://bxgw2u7j4b634" path="res://images/laser_turret.png" id="6_qxhyw"]
 [ext_resource type="Texture2D" uid="uid://buirp1h6onqai" path="res://images/AsteroidBrown.png" id="7_0tjls"]
@@ -22,6 +22,7 @@ colors = PackedColorArray(1, 1, 0, 1, 1, 1, 1, 0.137255)
 radius = 88.0057
 
 [node name="Main" type="Node2D"]
+script = ExtResource("1_eedai")
 
 [node name="background" type="Sprite2D" parent="."]
 position = Vector2(955, 537)
@@ -70,9 +71,6 @@ offset_top = -71.0
 offset_right = 104.0
 offset_bottom = -20.0
 
-[node name="WeaponsSystem" type="Node" parent="spaceship"]
-script = ExtResource("5_gf6oh")
-
 [node name="HardPoint1" type="Node2D" parent="spaceship"]
 position = Vector2(0, -46)
 script = ExtResource("7_6cr6a")

project.godot

@@ -12,7 +12,7 @@ config_version=5
 
 config/name="Star Cheese - The Final Fromage"
 run/main_scene="res://main.tscn"
-config/features=PackedStringArray("4.2", "Forward Plus")
+config/features=PackedStringArray("4.3", "Forward Plus")
 config/icon="res://icon.svg"
 
 [display]
@@ -24,7 +24,7 @@ window/size/viewport_height=1080
 
 ui_fire={
 "deadzone": 0.5,
-"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":32,"key_label":0,"unicode":32,"echo":false,"script":null)
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":32,"key_label":0,"unicode":32,"location":0,"echo":false,"script":null)
 ]
 }
 

spaceship.gd

@@ -8,10 +8,12 @@ extends CharacterBody2D
 signal fire  # Signal to start firing
 signal stop_fire  # Signal to stop firing
 
-var weapons_system
-
+var weapons_system: WeaponsSystem
+var event_bus: EventBus
 func _ready():
-	weapons_system = $WeaponsSystem  
+	weapons_system = get_node("/root/Main/WeaponsSystem")  
+	event_bus = get_node("/root/Main/MainEventBus")
+	event_bus.subscribe_to(get_node("/root/Main/InputEventScope"), "KeyboardInputEvent", Callable(self, "handle_keyboard_input"))
 
 func get_spaceship_orientation_vector() -> Vector2:
 	return -global_transform.y  
@@ -45,13 +47,14 @@ func handle_movement(delta: float) -> void:
 		var collision_normal = collision.get_normal()
 		velocity = velocity.slide(collision_normal)
 	
-func handle_weapons_input() -> void:
-	if Input.is_action_pressed("ui_fire"):
-		weapons_system.fire_all()
-
-	if Input.is_action_just_released("ui_fire"):
-		weapons_system.cease_fire_all()
-
+func handle_keyboard_input(event: KeyboardInputEvent):
+	if( event.action == "ui_fire" ):
+		if( event.pressed ):
+			weapons_system.fire_all()
+		else:
+			weapons_system.cease_fire_all()
+			
+	pass
+	
 func _process(delta: float) -> void:
 	handle_movement(delta)
-	handle_weapons_input()

tests.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3 uid="uid://dxxijo7vef7or"]
+
+[ext_resource type="Script" path="res://tests/tests.gd" id="1_dngg8"]
+
+[node name="tests" type="Node"]
+script = ExtResource("1_dngg8")

tests/test_eventbus.gd

@@ -0,0 +1,105 @@
+# res://tests/test_eventbus.gd
+class_name EventBusTests
+extends Node
+
+func _ready():
+	run_tests()
+
+func run_tests():
+	test_subscribe_and_publish()
+	test_dispose_subscription()
+	test_cancel_scope()
+	test_multiple_subscribers()
+	
+	# Test function: Test subscribing and publishing events
+func test_subscribe_and_publish() -> void:
+	var bus: DefaultEventBus = DefaultEventBus.new()
+	var scope: DefaultScope = DefaultScope.new()
+	var event_received: Flag = Flag.new()
+
+	var event_handler = func(_event: Event) -> int:
+		event_received.value = true
+		return EventResult.ResultType.KEEP_SUBSCRIPTION
+
+	bus.subscribe_to(scope, "TestEvent", event_handler)
+	var event: TestEvent = TestEvent.new(self)
+	bus.publish(scope, event)
+
+	# Assert that the event was received
+	assert(event_received.value == true, "Event was not received by subscriber")
+	bus.dispose()
+	
+	# Test function: Test disposing of a subscription after handling an event
+func test_dispose_subscription() -> void:
+	var bus: DefaultEventBus = DefaultEventBus.new()
+	var scope: DefaultScope = DefaultScope.new()
+	var event_received_times: Counter = Counter.new()
+
+	var event_handler = func(_event: Event) -> int:
+		event_received_times.value += 1
+		return EventResult.ResultType.DISPOSE_SUBSCRIPTION
+
+	bus.subscribe_to(scope, "TestEvent", event_handler)
+	var event: TestEvent = TestEvent.new(self)
+	bus.publish(scope, event)
+	bus.publish(scope, event)  # Publish a second time
+
+	# Assert that the event handler was called only once
+	assert(event_received_times.value == 1, "Event handler should have been called only once due to disposal")
+	bus.dispose()
+	
+	# Test function: Test canceling an event scope
+func test_cancel_scope() -> void:
+	var bus: DefaultEventBus = DefaultEventBus.new()
+	var scope: DefaultScope = DefaultScope.new()
+	var event_received: Flag = Flag.new()
+
+	var event_handler = func(_event: Event) -> int:
+		event_received.value = true
+		return EventResult.ResultType.KEEP_SUBSCRIPTION
+
+	bus.subscribe_to(scope, "TestEvent", event_handler)
+	bus.cancel_scope(scope)
+	var event: TestEvent = TestEvent.new(self)
+	bus.publish(scope, event)
+
+	# Assert that the event was not received after scope cancellation
+	assert(event_received.value == false, "Event should not have been received after scope cancellation")
+	bus.dispose()
+	
+
+# Test function: Test multiple subscribers receiving the same event
+func test_multiple_subscribers() -> void:
+	var bus: DefaultEventBus = DefaultEventBus.new()
+	var scope: DefaultScope = DefaultScope.new()
+	var event_received_by_handler1: Flag = Flag.new()
+	var event_received_by_handler2: Flag = Flag.new()
+
+	var event_handler1 = func(_event: Event) -> int:
+		event_received_by_handler1.value = true
+		return EventResult.ResultType.KEEP_SUBSCRIPTION
+
+	var event_handler2 = func(_event: Event) -> int:
+		event_received_by_handler2.value = true
+		return EventResult.ResultType.KEEP_SUBSCRIPTION
+
+	bus.subscribe_to(scope, "TestEvent", event_handler1)
+	bus.subscribe_to(scope, "TestEvent", event_handler2)
+	var event: TestEvent = TestEvent.new(self)
+	bus.publish(scope, event)
+
+	# Assert that both handlers received the event
+	assert(event_received_by_handler1.value == true, "First handler did not receive event")
+	assert(event_received_by_handler2.value == true, "Second handler did not receive event")
+	bus.dispose()
+
+class Flag:
+	var value = false
+
+class Counter:
+	var value = 0
+	
+class TestEvent extends Event:
+	func _init(_source: Variant = null) -> void:
+		super(_source)
+		type = "TestEvent"

tests/tests.gd

@@ -0,0 +1,8 @@
+extends Node
+
+func _ready() -> void:
+	EventBusTests.run_tests()
+	get_tree().quit()
+
+func _process(_delta: float) -> void:
+	pass

weapons_system.gd

@@ -1,3 +1,4 @@
+class_name WeaponsSystem
 extends Node
 
 var weapons = []