extends Node2D

## 静态弹幕障碍：以自己为圆心，一圈一圈地摆上**固定不动、不会发射**的子弹。
##
## 两种形态：
##  - solid = true ：实心障碍，挡路、能踩上去（注意：会连小怪一起挡住）
##  - solid = false：可以穿透，只做伤害判定 —— 配合 damage > 0 就是普通弹幕
##
## 落在实心地砖里、或跑出关卡范围的子弹会自动跳过。

const BULLET_SCRIPT := preload("res://scripts/bullet.gd")

@export var enabled: bool = true
## 每一圈的半径（单位：格）。默认 3 格、6 格、9 格
@export var radii_cells: Array[int] = [3, 6, 9]
## 每圈摆几颗
@export var per_ring: int = 20
## 一格多少像素（图块是 18）
@export var cell_size: float = 18.0
## 起始角度偏移（度），用来微调子弹摆在哪个方向
@export var angle_offset_deg: float = 0.0
## 子弹半径
@export var bullet_radius: int = 3
@export var bullet_color: Color = Color(1.0, 0.45, 0.85)
## 实心障碍：挡路、能踩上去。关掉的话就是可以穿透的纯弹幕
@export var solid: bool = false
## 碰到扣几颗心。0 = 不扣血
@export var damage: int = 1
## 超出这个范围的子弹不生成（默认整个关卡 468x270）
@export var bounds: Rect2 = Rect2(0, 0, 468, 270)
## 最多铺几圈
@export var max_rings: int = 3
## 跳过埋在地砖里的子弹
@export var skip_solid_ground: bool = true

var made: int = 0
var skipped_out: int = 0
var skipped_ground: int = 0

var _hurt_areas: Array = []


func _ready() -> void:
	if not enabled:
		return
	# 等一帧，确保 TileMapLayer 都已经就绪
	_build.call_deferred()


func _build() -> void:
	var layers := _tile_layers()
	var tex := BULLET_SCRIPT.circle_texture(bullet_radius, bullet_color)
	made = 0
	skipped_out = 0
	skipped_ground = 0
	_hurt_areas.clear()
	for i in mini(radii_cells.size(), max_rings):
		var radius: float = float(radii_cells[i]) * cell_size
		for k in per_ring:
			var ang := deg_to_rad(angle_offset_deg + 360.0 * float(k) / float(per_ring))
			var pos := global_position + Vector2(cos(ang), sin(ang)) * radius
			if not bounds.has_point(pos):
				skipped_out += 1
				continue
			if skip_solid_ground and _in_solid(layers, pos):
				skipped_ground += 1
				continue
			_make(pos, tex)
			made += 1


## 每帧检查一次：站在子弹里也会持续扣血
## （不能只靠 body_entered —— 玩家本来就在子弹里的话不会触发）
func _physics_process(_delta: float) -> void:
	if damage <= 0 or _hurt_areas.is_empty():
		return
	for area in _hurt_areas:
		if not is_instance_valid(area):
			continue
		for body in area.get_overlapping_bodies():
			if body.has_method("hurt"):
				body.hurt(damage)


func _tile_layers() -> Array:
	var root: Node = owner if owner != null else get_tree().current_scene
	if root == null:
		return []
	return root.find_children("*", "TileMapLayer", true, false)


## 这个点是不是埋在实心地砖里
func _in_solid(layers: Array, pos: Vector2) -> bool:
	for l in layers:
		var cell: Vector2i = l.local_to_map(l.to_local(pos))
		var sid: int = l.get_cell_source_id(cell)
		if sid == -1:
			continue
		var source := l.tile_set.get_source(sid) as TileSetAtlasSource
		if source == null:
			continue
		var data: TileData = source.get_tile_data(l.get_cell_atlas_coords(cell), 0)
		if data != null and data.get_collision_polygons_count(0) > 0:
			return true
	return false


func _make(pos: Vector2, tex: Texture2D) -> void:
	var body := StaticBody2D.new()
	if solid:
		body.collision_layer = 1
		body.collision_mask = 1
	else:
		# 不实心：谁都挡不住，只靠下面的伤害区域起作用
		body.collision_layer = 0
		body.collision_mask = 0
	add_child(body)
	body.global_position = pos

	var sprite := Sprite2D.new()
	sprite.texture = tex
	sprite.texture_filter = CanvasItem.TEXTURE_FILTER_NEAREST
	body.add_child(sprite)

	if solid:
		var shape := CollisionShape2D.new()
		var circle := CircleShape2D.new()
		circle.radius = float(bullet_radius)
		shape.shape = circle
		body.add_child(shape)

	if damage > 0:
		var area := Area2D.new()
		area.collision_layer = 4
		area.collision_mask = 2
		var hit := CollisionShape2D.new()
		var circle2 := CircleShape2D.new()
		circle2.radius = float(bullet_radius) + 1.0
		hit.shape = circle2
		area.add_child(hit)
		body.add_child(area)
		_hurt_areas.append(area)