Add skill management system with unlocker and save functionality

scripts/components/damage_component.gd

@@ -4,6 +4,9 @@ extends Node
 @export var damage: float = 0.25
 @export var area2d: Area2D
 @export var status_effect_data: StatusEffectDataResource
+@export var damage_timer: Timer
+
+var current_target: Node = null
 signal effect_inflicted(target: Node2D, effect: StatusEffectDataResource)
 
 
@@ -13,13 +16,34 @@ func _ready() -> void:
 		return
 
 	area2d.body_entered.connect(on_area2d_body_entered)
+	area2d.body_exited.connect(on_area2d_body_exited)
+	area2d.area_entered.connect(on_area2d_area_entered)
+
+	if damage_timer:
+		damage_timer.timeout.connect(on_damage_timer_timeout)
+
+
+func _process(_delta: float) -> void:
+	if not current_target:
+		return
+	if damage_timer:
+		return
+
+	process_entity_and_apply_damage(current_target)
 
 
 func deal_damage(target: HealthComponent) -> void:
 	target.decrease_health(damage)
 
 
-func on_area2d_body_entered(body: Node2D) -> void:
+func on_damage_timer_timeout() -> void:
+	if not current_target:
+		return
+
+	process_entity_and_apply_damage(current_target)
+
+
+func process_entity_and_apply_damage(body: Node2D) -> void:
 	if body.has_node("HealthComponent"):
 		var health_component: HealthComponent                   = body.get_node("HealthComponent")
 		var invulnerability_component: InvulnerabilityComponent = body.get_node_or_null("InvulnerabilityComponent")
@@ -34,3 +58,27 @@ func on_area2d_body_entered(body: Node2D) -> void:
 
 		if invulnerability_component:
 			invulnerability_component.activate()
+
+
+func on_area2d_body_entered(body: Node2D) -> void:
+	current_target = body
+
+	if damage_timer:
+		damage_timer.start()
+
+	process_entity_and_apply_damage(body)
+
+
+func on_area2d_body_exited(body: Node2D) -> void:
+	if body == current_target:
+		current_target = null
+		if damage_timer:
+			damage_timer.stop()
+
+
+func on_area2d_area_entered(area: Area2D) -> void:
+	if area == area2d:
+		return
+	var parent := area.get_parent()
+	if parent.has_node("DamageComponent"):
+		process_entity_and_apply_damage(parent)

scripts/components/skill_unlocker_component.gd

@@ -0,0 +1,34 @@
+class_name SkillUnlockerComponent
+extends Node
+
+@export var skill_manager: SkillManager
+
+@onready var game_manager: GM = $"/root/GameManager"
+
+
+func try_unlock_skill(skill_data: SkillData) -> void:
+	if not game_manager:
+		return
+
+	if game_manager.is_skill_unlocked(skill_data.name):
+		return
+
+	if game_manager.get_coins() < skill_data.cost:
+		return
+
+	game_manager.remove_coins(skill_data.cost)
+	game_manager.unlock_skill(skill_data.name)
+	skill_manager.add_skill(skill_data)
+
+
+func _input(event: InputEvent) -> void:
+	if event.is_action_pressed("unlock_skills"):
+		var available_skills: Array[SkillData] = skill_manager.available_skills
+		var skills: Array[String]              = []
+
+		for skill in available_skills:
+			skills.append(skill.name)
+
+		game_manager.unlock_skills(skills)
+		skill_manager.apply_unlocked_skills()
+		print("Unlocked skills: ", skills)