class_name Game
extends Node3D

# Takes care of game state including
# * player state
# * current level
# * player-world state (i.e. which items were picked up in the level)

signal item_picked_up(node_path:NodePath)

@onready var camera = %Camera
@onready var player:Player = %Player

@onready var build_system:BuildSystem = %BuildSystem

var picked_up_level_items:Array[NodePath] = []
var level = null

var _player_camera_offset:Vector3 = Vector3.ZERO

# Called when the node enters the scene tree for the first time.
func _ready():
	_player_camera_offset = camera.global_position - player.global_position + Vector3.UP * 1
	picked_up_level_items.clear()
	
	level = get_node("Level")
	
	InteractionSystem.player = player
	
	register_item_pickups()

# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(_delta):
	if build_system.is_active:
		player.process_mode = Node.PROCESS_MODE_DISABLED
	else:
		player.process_mode = Node.PROCESS_MODE_ALWAYS

		camera.global_position = player.global_position + _player_camera_offset
		camera.look_at(player.global_position)

func register_item_pickups() -> void:
	# When saving a game we need to know which items were picked up.
	for pickup_item in get_tree().get_nodes_in_group("pickup_item"):
		pickup_item.connect("item_picked_up", on_item_pickup)

func on_item_pickup(node_path:NodePath):
	picked_up_level_items.append(node_path)
	item_picked_up.emit(node_path)

func load_level(level_resource_path:String) -> void:
	var level_resource = load(level_resource_path) as PackedScene
	
	var level_node = get_node("Level") as Node3D
	assert(level_node != null)
	
	level_node.queue_free()
	remove_child(level_node)
	
	level = level_resource.instantiate()
	name = "Level"
	add_child(level)

	register_item_pickups()

func save_game(game_profile_path:String):
	var save_data:SaveGameResource = SaveGameResource.new()
	
	save_data.level = level.scene_file_path
	save_data.level_pickup_items = picked_up_level_items
	save_data.player_transform = player.global_transform
	
	for node:Node in get_tree().get_nodes_in_group("quest_state"):
		save_data.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_data.quest_states[node.name][property.name] = node.get(property.name)
	
	for item_stack in player.inventory.get_item_stacks():
		save_data.inventory.append({"item": item_stack.item, "count": item_stack.count})
	
	for structure:BuiltStructure in get_tree().get_nodes_in_group("built_structure"):
		var built_structure_resource = BuiltStructureResource.new()
		built_structure_resource.global_transform = structure.global_transform
		built_structure_resource.item = structure.item
		var item_array = save_data.built_structures.get_or_add(structure.item, [])
		
		item_array.append(structure.global_transform)

	print("Saving game: " + game_profile_path + "/savegame.tres")
	ResourceSaver.save(save_data, game_profile_path + "/savegame.tres")

func load_game(game_profile_path:String) -> void:
	print("Loading game: " + game_profile_path + "/savegame.tres")
	var save_data:SaveGameResource = load(game_profile_path + "/savegame.tres") as SaveGameResource
	
	load_level(save_data.level)
	
	player.global_transform = save_data.player_transform
	player.init_look_target_direction()
	
	# Quest state
	for quest_state:Node in get_tree().get_nodes_in_group("quest_state"):
		for property in quest_state.get_property_list():
			if (property.usage & PROPERTY_USAGE_STORAGE != 0) and (property.usage & PROPERTY_USAGE_SCRIPT_VARIABLE) != 0 and (save_data.quest_states.has(quest_state.name)) and (save_data.quest_states[quest_state.name].has(property.name)):
				quest_state.set(property.name, save_data.quest_states[quest_state.name][property.name])
	
	# Inventory
	player.inventory.clear()
	var inventory_item_stacks:Array[ItemStack] = player.inventory.get_item_stacks()
	
	assert(inventory_item_stacks.size() >= save_data.inventory.size())
	
	for i in range(save_data.inventory.size()):
		inventory_item_stacks[i].item = save_data.inventory[i]["item"]
		inventory_item_stacks[i].count = save_data.inventory[i]["count"]
	
	# Picked up items
	for item_path in save_data.level_pickup_items:
		if get_tree().root.has_node(item_path):
			var item_node = get_tree().root.get_node(item_path)
			picked_up_level_items.append(item_path)
			item_node.queue_free()
	
	# Built structures
	for item:ItemResource in save_data.built_structures.keys():
		var item_transform_array = save_data.built_structures[item] as Array[Transform3D]
		for structure_transform in item_transform_array:
			build_system.build_structure(item, structure_transform)