extends Area2D

var direction := Vector2.UP
var projectile_speed := 600.0
var damage := 1.0
var max_range := 800.0
var weapon_kind := ItemDefinition.WeaponKind.PLASMA
var _distance_travelled := 0.0
var _already_hit: Dictionary = {}

func _ready() -> void:
	body_entered.connect(_on_body_entered)
	area_entered.connect(_on_area_entered)
	rotation = direction.angle()

func configure(
	start_position: Vector2,
	travel_direction: Vector2,
	kind: int,
	speed: float,
	projectile_damage: float,
	projectile_range: float
) -> void:
	global_position = start_position
	direction = travel_direction.normalized()
	weapon_kind = kind
	projectile_speed = speed
	damage = projectile_damage
	max_range = projectile_range

func _physics_process(delta: float) -> void:
	var step := projectile_speed * delta
	var previous_position := global_position
	var next_position := previous_position + direction * step
	var query := PhysicsRayQueryParameters2D.create(
		previous_position,
		next_position,
		collision_mask,
		[get_rid()]
	)
	var result := get_world_2d().direct_space_state.intersect_ray(query)
	if not result.is_empty():
		global_position = result["position"]
		_hit_target(result.get("collider"))
		return
	global_position = next_position
	_distance_travelled += step
	if _distance_travelled >= max_range:
		queue_free()

func _draw() -> void:
	match weapon_kind:
		ItemDefinition.WeaponKind.PLASMA:
			draw_circle(Vector2.ZERO, 6.0, Color(0.3, 0.85, 1.0, 0.95))
			draw_circle(Vector2.ZERO, 3.0, Color(0.85, 0.98, 1.0, 1.0))
		ItemDefinition.WeaponKind.MACHINE_GUN:
			draw_rect(Rect2(-7.0, -2.0, 14.0, 4.0), Color(1.0, 0.82, 0.38, 1.0))
		ItemDefinition.WeaponKind.MISSILE:
			draw_colored_polygon(PackedVector2Array([
				Vector2(10, 0), Vector2(-7, -4), Vector2(-4, 0), Vector2(-7, 4),
			]), Color(1.0, 0.42, 0.2, 1.0))

func _on_body_entered(body: Node2D) -> void:
	_hit_target(body)

func _on_area_entered(area: Area2D) -> void:
	_hit_target(area)

func _hit_target(target: Node) -> void:
	if weapon_kind == ItemDefinition.WeaponKind.MISSILE:
		_explode_at_target(target)
	else:
		_apply_damage_once(target)
	queue_free()

func _explode_at_target(impact_target: Node) -> void:
	_apply_damage_once(impact_target)
	var explosion_shape := CircleShape2D.new()
	explosion_shape.radius = 120.0
	var query := PhysicsShapeQueryParameters2D.new()
	query.shape = explosion_shape
	query.transform = Transform2D(0.0, global_position)
	query.collision_mask = 4 # Enemy physics layer 3.
	for result in get_world_2d().direct_space_state.intersect_shape(query, 32):
		_apply_damage_once(result.get("collider"))

func _apply_damage_once(target: Variant) -> void:
	if not (target is Node):
		return
	var instance_id: int = target.get_instance_id()
	if _already_hit.has(instance_id):
		return
	_already_hit[instance_id] = true
	if target.has_method("take_damage"):
		target.call("take_damage", damage)