class_name RootUI
extends CanvasLayer

@export var startup_scene:PackedScene
@export var game_scene:PackedScene
@export var autostart_game_scene:bool = true

@onready var scene = %Scene
@onready var ui_panels:Array = [ %MainMenuUI, %NewGameUI, %GameUI ]
@onready var active_ui_panel:Control = null

enum ROOT_UI_STATE { UNDEFINED, MENU, GAME }
var _root_ui_state:ROOT_UI_STATE = ROOT_UI_STATE.UNDEFINED

var current_level_resource:String

func _ready():
	if autostart_game_scene:
		load_scene(game_scene)
		set_root_ui_state(ROOT_UI_STATE.GAME)
	else:
		set_root_ui_state(ROOT_UI_STATE.MENU)


func activate_ui_panel(ui_panel:Control):
	for control in ui_panels:
		if control == ui_panel:
			control.visible = true
		else:
			control.visible = false
	
	active_ui_panel = ui_panel


func load_scene(scene_resource:PackedScene):
	for scene_child in scene.get_children():
		scene_child.queue_free()
		scene_child.get_parent().remove_child(scene_child)
	
	print("Loading level '" + scene_resource.resource_path + "'")
	scene.add_child(scene_resource	.instantiate())
	current_level_resource = scene_resource.resource_path


func save_game():
	var player:Player = scene.find_child("Player", true, false)
	
	if player == null:
		push_error("Cannot load game: no player found!")
		return
	
	var save_game:SaveGame = SaveGame.new()
	
	save_game.level = current_level_resource
	save_game.level_pickup_items = %GameUI.picked_up_level_items
	save_game.player_transform = player.global_transform
	
	for node:Node in get_tree().get_nodes_inv_group("quest_state"):
		save_game.quest_states[node.name] = {}
	
		for property in node.get_property_list():
			if (property.usage & PROPERTY_USAGE_STORAGE != 0) and (property.usage & PROPERTY_USAGE_SCRIPT_VARIABLE) != 0:
				save_game.quest_states[node.name][property.name] = node.get(property.name)
	
	for item_stack in player.inventory.get_item_stacks():
		save_game.inventory.append({"item": item_stack.item, "count": item_stack.count})
	
	ResourceSaver.save(save_game, "user://savegame.tres")
	activate_ui_panel(%GameUI)


func load_game():
	set_root_ui_state(RootUI.ROOT_UI_STATE.UNDEFINED)
	
	%GameUI.picked_up_level_items.clear()
	
	var save_game:SaveGame = load("user://savegame.tres") as SaveGame
	var level_resource:PackedScene = load(save_game.level)
	load_scene(level_resource)

	var player:Player = scene.find_child("Player", true, false)
	
	if player == null:
		push_error("Cannot load game: no player found!")
		return

	print("main.gd:load_game() Player = " + str(player))
	player.global_transform = save_game.player_transform
	
	# Quest state
	for node:Node in get_tree().get_nodes_in_group("quest_state"):
		for property in node.get_property_list():
			if (property.usage & PROPERTY_USAGE_STORAGE != 0) and (property.usage & PROPERTY_USAGE_SCRIPT_VARIABLE) != 0:
				node.set(property.name, save_game.quest_states[node.name][property.name])
	
	# Inventory
	player.inventory.clear()
	var inventory_item_stacks:Array[ItemStack] = player.inventory.get_item_stacks()
	
	assert(inventory_item_stacks.size() >= save_game.inventory.size())
	
	for i in range(save_game.inventory.size()):
		inventory_item_stacks[i].item = save_game.inventory[i]["item"]
		inventory_item_stacks[i].count = save_game.inventory[i]["count"]
	
	# Picked up items
	for item_path in save_game.level_pickup_items:
		if get_tree().root.has_node(item_path):
			var item_node = get_tree().root.get_node(item_path)
			%GameUI.picked_up_level_items.append(item_path)
			item_node.queue_free()
	
	set_root_ui_state(RootUI.ROOT_UI_STATE.GAME)


func set_root_ui_state(state:ROOT_UI_STATE):
	if _root_ui_state == state:
		return
	
	if state == ROOT_UI_STATE.GAME:
		%GameUI.activate_game_scene(scene.get_child(0))
		activate_ui_panel(%GameUI)
	elif state == ROOT_UI_STATE.MENU:
		load_scene(startup_scene)
		%GameUI.activate_game_scene(null)
		activate_ui_panel(%MainMenuUI)
	
	_root_ui_state = state


func _on_start_game_button_pressed():
	load_scene(game_scene)
	set_root_ui_state(ROOT_UI_STATE.GAME)


func _on_quit_button_pressed():
	get_tree().quit()


func _on_new_game_button_pressed():
	activate_ui_panel(%NewGameUI)


func _to_main_menu_button_pressed():
	set_root_ui_state(ROOT_UI_STATE.MENU)