class_name PlayerBullet
extends Area2D
## 玩家子弹：沿自身方向直线飞行（斜射弹共享此类），命中敌机造成伤害。

const SPEED := 760.0
const TEX := preload("res://assets/svg/bullet_player.svg")

var direction := Vector2.UP


func _ready() -> void:
	collision_layer = 2
	# 4 空中敌机 + 32 地面/海面单位（只被打，不与玩家机体碰撞）
	collision_mask = 4 | 32
	var sprite := Sprite2D.new()
	sprite.texture = TEX
	add_child(sprite)
	var shape := CollisionShape2D.new()
	var rect := RectangleShape2D.new()
	rect.size = Vector2(6.0, 16.0)
	shape.shape = rect
	add_child(shape)
	# 旋转节点本身：贴图与碰撞矩形一起对齐弹道方向
	rotation = Vector2.UP.angle_to(direction)
	area_entered.connect(_on_area_entered)


func _process(delta: float) -> void:
	position += direction * SPEED * delta
	if global_position.y < -30.0 or global_position.x < -30.0 or global_position.x > 570.0:
		queue_free()


func _on_area_entered(area: Area2D) -> void:
	if area is EnemyBase:
		(area as EnemyBase).apply_damage(1)
		queue_free()