class_name SaveState extends Resource
## Serializable container for gameplay state.

const CURRENT_VERSION := 0
const PERSISTENT_GROUP := "Persistent"
const SERIALIZE_METHOD := "serialize"
const DESERIALIZE_METHOD := "deserialize"

@export var save_version := CURRENT_VERSION

@export var level_path: String

@export var persistent_state: Dictionary[String, Dictionary] = {}

@export_group("WorldManager State")
@export var grunk_tank_limit: int
@export var mp3_player_unlocked: bool
@export var toothbrush_unlocked: bool
@export var stickers_unlocked: bool

@export var grunk_tank: float
@export var grunk_vault: float
@export var alert_level: int


static func node_key(node: Node, world: World) -> String:
	return str(world.level_root.get_path_to(node))


func load_to_world(world: World) -> void:
	if level_path != world.current_level_scene.resource_path:
		push_warning(
			"This save is for ",
			level_path,
			" but the loaded level is for ",
			world.current_level_scene.resource_path
		)

	world.manager.grunk_tank_limit = grunk_tank_limit
	world.manager.mp3_player_unlocked = mp3_player_unlocked
	world.manager.toothbrush_unlocked = toothbrush_unlocked
	world.manager.stickers_unlocked = stickers_unlocked
	world.manager.grunk_tank = grunk_tank
	world.manager.grunk_vault = grunk_vault
	world.manager.alert_level = alert_level

	var persistent := world.get_tree().get_nodes_in_group(PERSISTENT_GROUP)

	for node: Node in persistent:
		var key := SaveState.node_key(node, world)
		if key in persistent_state:
			# Node is in our persistent state, so load it with data.
			Callable(node, DESERIALIZE_METHOD).call(persistent_state[key])
		else:
			# Node isn't in our persistent state, so it must have been destroyed.
			node.queue_free()


static func serialize(world: World) -> SaveState:
	var save := SaveState.new()

	save.level_path = world.current_level_scene.resource_path

	save.grunk_tank_limit = world.manager.grunk_tank_limit
	save.mp3_player_unlocked = world.manager.mp3_player_unlocked
	save.toothbrush_unlocked = world.manager.toothbrush_unlocked
	save.stickers_unlocked = world.manager.stickers_unlocked
	save.grunk_tank = world.manager.grunk_tank
	save.grunk_vault = world.manager.grunk_vault
	save.alert_level = world.manager.alert_level

	# NOTE: I'm assuming that `persistent` will have the same order ever time the world is loaded.
	# This may not be the case. If so, we need to find a different way to uniquely identify nodes.
	var persistent := world.get_tree().get_nodes_in_group(PERSISTENT_GROUP)

	for node: Node in persistent:
		var key := SaveState.node_key(node, world)
		var data: Dictionary = Callable(node, SERIALIZE_METHOD).call()
		save.persistent_state[key] = data

	return save