class_name WaveSpawner
extends Node
## 波次生成器：时间线循环刷敌，每轮提升难度。

var difficulty := 1.0
var game: Game


func _ready() -> void:
	call_deferred("_run")


func _run() -> void:
	game = get_tree().get_first_node_in_group("game") as Game
	await get_tree().create_timer(0.8).timeout
	var round_num := 1
	while true:
		difficulty = minf(1.0 + (round_num - 1) * 0.12, 1.8)
		await _play_round()
		await _wait_playing()
		# 关底 Boss 战
		if game != null and is_instance_valid(game):
			game.show_boss_warning()
		await _timer(2.0)
		await _wait_playing()
		var boss: Boss = null
		if game != null and is_instance_valid(game):
			boss = game.spawn_boss(difficulty)
		while boss != null and is_instance_valid(boss):
			await _timer(0.3)
		await _wait_playing()
		await _timer(2.5)
		round_num += 1
		await get_tree().create_timer(2.5).timeout


func _play_round() -> void:
	await _wait_playing()
	await _column(140.0)
	await _timer(3.2)

	await _wait_playing()
	_v_formation(270.0)
	await _timer(3.8)

	await _wait_playing()
	_sine_squad(170.0)
	_sine_squad(370.0)
	await _timer(3.8)

	await _wait_playing()
	_fortress(120.0)
	_fortress(420.0)
	await _timer(2.6)

	await _wait_playing()
	await _column(400.0)
	await _timer(0.8)
	await _column(120.0)
	await _timer(3.0)

	await _wait_playing()
	_medium(1, 210.0)
	await _timer(4.0)

	await _wait_playing()
	_ship(190.0)
	await _timer(4.0)

	await _wait_playing()
	_v_formation(160.0)
	await _timer(1.4)
	_v_formation(380.0)
	await _timer(3.6)

	await _wait_playing()
	_sine_squad(270.0)
	_fortress(270.0)
	await _timer(3.4)

	await _wait_playing()
	_medium(-1, 260.0)
	await _column(270.0)
	_ship(380.0)
	await _timer(4.2)


## 游戏结束时挂起等待，避免继续刷敌
func _wait_playing() -> void:
	while game == null or game.state != Game.State.PLAYING:
		await get_tree().create_timer(0.5).timeout


func _timer(duration: float) -> void:
	await get_tree().create_timer(duration).timeout


## 纵队：同一直线依次下压，头机掉宝
func _column(x: float) -> void:
	for i in 5:
		_spawn_small(x, -30.0 - 46.0, 190.0 * difficulty, 0.0, 2.0, 0.0, true, 250.0 * difficulty, i == 0)
		await _timer(0.32)


## V 字编队：5 机整体压境，仅领队开火并掉宝
func _v_formation(center_x: float) -> void:
	var offsets := [Vector2(0.0, -30.0), Vector2(-44.0, -66.0), Vector2(44.0, -66.0), Vector2(-88.0, -102.0), Vector2(88.0, -102.0)]
	for i in offsets.size():
		var offset: Vector2 = offsets[i]
		var is_leader := i == 0
		_spawn_small(center_x + offset.x, offset.y, 150.0 * difficulty, 16.0, 1.6, 0.0, is_leader, 240.0 * difficulty, is_leader)


## 摆动机队：同路径依次进场、正弦横摆，头机掉宝
func _sine_squad(x: float) -> void:
	for i in 4:
		_spawn_small(x, -30.0, 130.0 * difficulty, 72.0, 1.8, 0.0, randf() < 0.5, 230.0 * difficulty, i == 0)
		await _timer(0.4)


## 中型轰炸机横掠
func _medium(p_side: int, y: float) -> void:
	var enemy := EnemyMedium.new()
	enemy.setup(p_side, y, 112.0 * difficulty, 235.0 * difficulty, maxf(0.9, 1.6 / difficulty))
	_add_enemy(enemy)


## 地面固定堡垒
func _fortress(x: float) -> void:
	var enemy := EnemyFortress.new()
	enemy.setup(x, -60.0, difficulty)
	_add_enemy(enemy)


## 驱逐舰
func _ship(x: float) -> void:
	var enemy := EnemyShip.new()
	enemy.setup(x, -140.0, difficulty)
	_add_enemy(enemy)


func _spawn_small(
	x: float,
	y: float,
	vy: float,
	sway_amp: float,
	sway_freq: float,
	phase: float,
	shoot: bool,
	bullet_speed: float,
	drop := false
) -> void:
	var enemy := EnemySmall.new()
	enemy.setup(x, y, vy, sway_amp, sway_freq, phase, shoot, bullet_speed)
	enemy.drops_powerup = drop
	_add_enemy(enemy)


func _add_enemy(enemy: EnemyBase) -> void:
	var container := get_tree().get_first_node_in_group("enemies")
	if container == null:
		return
	container.add_child(enemy)