extends Node2D
## 游戏主控：状态机 + 关卡列表 + 分数/生命权威数据 + 信号连接。
## 状态：MENU / PLAYING / LEVEL_CLEAR / GAME_OVER
##
## 流程：
##   MENU       → 空格开始 → PLAYING（关卡 1）
##   PLAYING    → 通关 → LEVEL_CLEAR（空格下一关）
##               → 命数归零 → GAME_OVER（空格重开/回菜单）
##   LEVEL_CLEAR → 最后一关 → 显示"通关" → 回 MENU
##   GAME_OVER  → 空格回 MENU

enum GameState { MENU, PLAYING, LEVEL_CLEAR, GAME_OVER }

# 关卡数据（按顺序加载）
const LEVELS: Array = [
	preload("res://data/level_1.gd"),
	preload("res://data/level_2.gd"),
	preload("res://data/level_3.gd"),
]

# 场景切换
const MainMenuScene: PackedScene = preload("res://scenes/ui/main_menu.tscn")
const PowerUpScene: PackedScene = preload("res://scenes/power_up.tscn")

@export var initial_lives: int = 3

@onready var world: Node2D = $World
@onready var level: Node2D = $World/Level
@onready var paddle: CharacterBody2D = $World/Paddle
@onready var ball: CharacterBody2D = $World/Ball
@onready var lose_zone: Area2D = $World/LoseZone
@onready var hud: CanvasLayer = $UI/HUD
@onready var audio: Node = $Audio
@onready var power_ups: Node2D = $World/PowerUps

var state: GameState = GameState.MENU
var score: int = 0
var lives: int = initial_lives
var current_level_index: int = 0
var _remaining_bricks: int = 0

func _ready() -> void:
	# 信号连接
	ball.lost.connect(_on_ball_lost)
	ball.brick_hit.connect(_on_ball_hit_brick)
	lose_zone.body_entered.connect(_on_lose_zone_body_entered)
	# 初始状态：菜单
	_show_menu()

func _process(_delta: float) -> void:
	match state:
		GameState.MENU:
			pass  # 菜单场景自己处理输入
		GameState.LEVEL_CLEAR:
			if Input.is_key_pressed(KEY_SPACE):
				_go_to_next_level()
		GameState.GAME_OVER:
			if Input.is_key_pressed(KEY_SPACE):
				_show_menu()

# ───────── 状态切换 ─────────

func _show_menu() -> void:
	state = GameState.MENU
	clear_power_ups()
	world.visible = false
	hud.visible = false
	# 加载菜单场景作为 UI 子节点（如果还没在）
	var menu: Control = $UI.get_node_or_null("MainMenu")
	if menu == null:
		menu = MainMenuScene.instantiate()
		menu.name = "MainMenu"
		$UI.add_child(menu)
		menu.start_pressed.connect(start_game)
		menu.quit_pressed.connect(_on_quit_pressed)
	menu.visible = true  # 重新显示（可能之前被 hidden）

func _on_quit_pressed() -> void:
	get_tree().quit()

func start_game() -> void:
	# 主菜单"开始"按钮调用
	# 关闭主菜单（先隐藏，再删除）
	var menu: Control = $UI.get_node_or_null("MainMenu")
	if menu:
		menu.visible = false
		menu.queue_free()
	score = 0
	lives = initial_lives
	current_level_index = 0
	paddle.reset_state()
	world.visible = true
	hud.visible = true
	hud.update_score(score)
	hud.update_lives(lives)
	_load_current_level()
	state = GameState.PLAYING

func _load_current_level() -> void:
	clear_power_ups()
	paddle.reset_state()
	level.load_layout(LEVELS[current_level_index].LAYOUT)
	_remaining_bricks = level.get_child_count()
	ball.reset_to_paddle()
	hud.show_message("Level %d — 按 空格 发球" % (current_level_index + 1))

func _go_to_next_level() -> void:
	current_level_index += 1
	if current_level_index >= LEVELS.size():
		# 通关
		_game_complete()
		return
	_load_current_level()
	state = GameState.PLAYING

func _game_complete() -> void:
	state = GameState.GAME_OVER
	hud.show_message("通关！总分 %d — 按 空格 回主菜单" % score)

func _game_over() -> void:
	state = GameState.GAME_OVER
	hud.show_message("Game Over — 按 空格 回主菜单")

# ───────── 信号 ─────────

func _on_ball_lost() -> void:
	audio.play_lost()
	lives -= 1
	hud.update_lives(lives)
	if lives <= 0:
		_game_over()
	else:
		ball.reset_to_paddle()
		hud.show_message("按 空格 重新发球")

func _on_ball_hit_brick(brick: Node) -> void:
	if not brick.has_method("hit"):
		return
	if not brick.destroyed.is_connected(_on_brick_destroyed):
		brick.destroyed.connect(_on_brick_destroyed)
	if not brick.power_up_dropped.is_connected(_on_brick_power_up_dropped):
		brick.power_up_dropped.connect(_on_brick_power_up_dropped)
	audio.play_hit()
	brick.hit()

func _on_brick_power_up_dropped(spawn_position: Vector2) -> void:
	spawn_power_up(spawn_position)

func _on_brick_destroyed(points: int) -> void:
	score += points
	_remaining_bricks -= 1
	hud.update_score(score)
	audio.play_break()
	if _remaining_bricks <= 0 and state == GameState.PLAYING:
		state = GameState.LEVEL_CLEAR
		hud.show_message("Level Clear! — 按 空格 进下一关")
		audio.play_win()

func _on_lose_zone_body_entered(body: Node) -> void:
	if body == ball:
		ball.lost.emit()

# ───────── 道具 ─────────

func spawn_power_up(position: Vector2) -> void:
	var pu: Area2D = PowerUpScene.instantiate()
	power_ups.add_child(pu)
	pu.position = position
	pu.collected.connect(_on_power_up_collected)

func _on_power_up_collected(kind: String) -> void:
	audio.play_break()  # 蹭原来的音效；有需要再单独加
	match kind:
		"wide_paddle":
			paddle.widen()
			hud.show_message("挡板变宽！")
		"multi_ball":
			hud.show_message("多球（暂未实现）")
		"slow_ball":
			hud.show_message("减速（暂未实现）")
		"extra_life":
			lives += 1
			hud.update_lives(lives)
			hud.show_message("+1 命")
		_:
			pass

func clear_power_ups() -> void:
	for child in power_ups.get_children():
		child.queue_free()