extends Node
## 联机总入口（Autoload 名：Net）
##
## 职责边界：只负责「选传输层 + 开局/加入/断开 + 玩家生成回收」。
## 玩法代码不直接接触 MultiplayerPeer —— 以后要把 ENet 换成 Steam P2P，
## 只需要改本文件的 host_game / join_game 两个函数，RPC 与 Spawner 层不用动。
##
## 本机双开调试（命令行）：
##   godot --path <项目目录> -- --host
##   godot --path <项目目录> -- --join 127.0.0.1

const PORT: int = 7000
const MAX_PLAYERS: int = 8
const DEFAULT_ADDRESS: String = "127.0.0.1"
## 所有玩家节点都会加入这个组，方便整批清场
const PLAYER_GROUP: String = "net_player"

var _spawner: MultiplayerSpawner = null
var _menu_root: Control = null
var _hud_root: Control = null
var _address_edit: LineEdit = null
var _menu_status: Label = null
var _hud_status: Label = null


func _ready() -> void:
	multiplayer.peer_connected.connect(_on_peer_connected)
	multiplayer.peer_disconnected.connect(_on_peer_disconnected)
	multiplayer.connected_to_server.connect(_on_connected_to_server)
	multiplayer.connection_failed.connect(_on_connection_failed)
	multiplayer.server_disconnected.connect(_on_server_disconnected)
	_build_ui()
	call_deferred("_apply_cmdline")


# ---------------- 对外接口 ----------------

## 世界根节点在 _ready 里调用，把 MultiplayerSpawner 托管给 Net。
func bind_spawner(spawner: MultiplayerSpawner) -> void:
	_spawner = spawner


## 创建主机。ENet 是客户端-服务器模型，主机同时是服务器与玩家。
func host_game() -> void:
	var peer := ENetMultiplayerPeer.new()
	var err := peer.create_server(PORT, MAX_PLAYERS)
	if err != OK:
		_set_status("创建主机失败：%s" % error_string(err))
		return
	multiplayer.multiplayer_peer = peer
	_show_game_ui()
	print("[Net] 主机已启动，端口 %d" % PORT)
	# 服务器自己也要一个角色。延后一帧，等各端场景就绪。
	call_deferred("_spawn_player", 1)


## 加入主机。address 为主机在局域网内的内网 IP。
func join_game(address: String = DEFAULT_ADDRESS) -> void:
	var target := address.strip_edges()
	if target.is_empty():
		target = DEFAULT_ADDRESS
	var peer := ENetMultiplayerPeer.new()
	var err := peer.create_client(target, PORT)
	if err != OK:
		_set_status("连接失败：%s" % error_string(err))
		return
	multiplayer.multiplayer_peer = peer
	_set_status("正在连接 %s:%d …" % [target, PORT])
	print("[Net] 正在连接 %s:%d" % [target, PORT])


## 断开并清场，回到主菜单。
func leave_game() -> void:
	multiplayer.multiplayer_peer = null
	_clear_players()
	Input.mouse_mode = Input.MOUSE_MODE_VISIBLE
	_show_menu_ui()
	_set_status("已断开")


# ---------------- 网络事件 ----------------

func _on_peer_connected(id: int) -> void:
	# 只有服务器生成角色，客户端靠 MultiplayerSpawner 自动收到同一份。
	if multiplayer.is_server():
		call_deferred("_spawn_player", id)


func _on_peer_disconnected(id: int) -> void:
	if multiplayer.is_server():
		_despawn_player(id)


func _on_connected_to_server() -> void:
	_show_game_ui()
	print("[Net] 已连接，等待主机生成角色")


func _on_connection_failed() -> void:
	multiplayer.multiplayer_peer = null
	_set_status("连接失败：主机无响应")


func _on_server_disconnected() -> void:
	multiplayer.multiplayer_peer = null
	_clear_players()
	Input.mouse_mode = Input.MOUSE_MODE_VISIBLE
	_show_menu_ui()
	_set_status("主机已关闭")


# ---------------- 玩家生成与回收 ----------------

func _spawn_player(peer_id: int) -> void:
	if _spawner == null or not multiplayer.is_server():
		return
	var parent := _spawner.get_node_or_null(_spawner.spawn_path)
	if parent == null or parent.has_node(str(peer_id)):
		return
	_spawner.spawn(peer_id)


func _despawn_player(peer_id: int) -> void:
	if _spawner == null:
		return
	var parent := _spawner.get_node_or_null(_spawner.spawn_path)
	if parent == null:
		return
	var node := parent.get_node_or_null(str(peer_id))
	if node != null:
		node.queue_free()


func _clear_players() -> void:
	for node in get_tree().get_nodes_in_group(PLAYER_GROUP):
		node.queue_free()


# ---------------- 命令行调试入口 ----------------

func _apply_cmdline() -> void:
	var args := OS.get_cmdline_user_args()
	if args.has("--host"):
		host_game()
	elif args.has("--join"):
		var index := args.find("--join")
		var address := DEFAULT_ADDRESS
		if index + 1 < args.size():
			address = args[index + 1]
		join_game(address)


# ---------------- 界面 ----------------

func _build_ui() -> void:
	var menu_layer := CanvasLayer.new()
	menu_layer.name = "NetMenu"
	menu_layer.layer = 20
	add_child(menu_layer)
	_menu_root = _build_menu()
	menu_layer.add_child(_menu_root)

	var hud_layer := CanvasLayer.new()
	hud_layer.name = "NetHud"
	hud_layer.layer = 19
	add_child(hud_layer)
	_hud_root = _build_hud()
	_hud_root.visible = false
	hud_layer.add_child(_hud_root)


func _build_menu() -> Control:
	var center := CenterContainer.new()
	center.set_anchors_preset(Control.PRESET_FULL_RECT)

	var panel := PanelContainer.new()
	center.add_child(panel)

	var box := VBoxContainer.new()
	box.add_theme_constant_override("separation", 10)
	panel.add_child(box)

	var title := Label.new()
	title.text = "联机测试"
	title.add_theme_font_size_override("font_size", 20)
	box.add_child(title)

	_address_edit = LineEdit.new()
	_address_edit.text = DEFAULT_ADDRESS
	_address_edit.custom_minimum_size = Vector2(240, 0)
	box.add_child(_address_edit)

	var host_button := Button.new()
	host_button.text = "创建主机"
	host_button.pressed.connect(host_game)
	box.add_child(host_button)

	var join_button := Button.new()
	join_button.text = "加入主机"
	join_button.pressed.connect(_on_join_pressed)
	box.add_child(join_button)

	_menu_status = Label.new()
	_menu_status.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	_menu_status.custom_minimum_size = Vector2(240, 0)
	box.add_child(_menu_status)

	var hint := Label.new()
	hint.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	hint.custom_minimum_size = Vector2(240, 0)
	hint.modulate = Color(1, 1, 1, 0.7)
	hint.text = "局域网内填主机的内网 IP；本机双开测试填 %s" % DEFAULT_ADDRESS
	box.add_child(hint)

	return center


func _build_hud() -> Control:
	var layer_root := Control.new()
	layer_root.set_anchors_preset(Control.PRESET_FULL_RECT)
	layer_root.mouse_filter = Control.MOUSE_FILTER_IGNORE

	var box := VBoxContainer.new()
	box.position = Vector2(16, 12)
	box.mouse_filter = Control.MOUSE_FILTER_IGNORE
	layer_root.add_child(box)

	_hud_status = Label.new()
	box.add_child(_hud_status)

	var hint := Label.new()
	hint.modulate = Color(1, 1, 1, 0.7)
	hint.text = "F10 断开  ·  Esc 释放鼠标"
	box.add_child(hint)

	return layer_root


func _on_join_pressed() -> void:
	join_game(_address_edit.text)


func _unhandled_key_input(event: InputEvent) -> void:
	if event is InputEventKey and event.pressed and not event.echo \
			and event.keycode == KEY_F10 and multiplayer.multiplayer_peer != null:
		leave_game()
		get_viewport().set_input_as_handled()


func _show_game_ui() -> void:
	_menu_root.visible = false
	_hud_root.visible = true
	_update_hud()


func _show_menu_ui() -> void:
	_menu_root.visible = true
	_hud_root.visible = false


func _set_status(text: String) -> void:
	if _menu_status != null:
		_menu_status.text = text


func _update_hud() -> void:
	var role := "主机" if multiplayer.is_server() else "客户端"
	var players := multiplayer.get_peers().size() + 1
	_hud_status.text = "联机中 · %s · 玩家 %d" % [role, players]