class_name OverworldSingleton extends Node

signal mapChanged(map:PackedScene, playerDestinationNodeName:String)


var newMapPath:String
var hasFadedOut:bool = false
var playerDestinationNodeName:String
var newMapLoaded:bool = false

func isMapChanging() -> bool:
	return newMapPath != ""

func _enter_tree() -> void:
	pass

func _exit_tree() -> void:
	TRANSITION.fadeOutEnd.disconnect(onFadeOutEnd)
	TRANSITION.fadeInEnd.disconnect(onFadeInEnd)

func _process(_delta:float) -> void:
	if(!isMapChanging()):
		return

	var status = ResourceLoader.load_threaded_get_status(newMapPath)
	if status == ResourceLoader.THREAD_LOAD_FAILED:
		push_error("Failed to load map: " + newMapPath)
		newMapPath = ""
		
	elif status == ResourceLoader.THREAD_LOAD_INVALID_RESOURCE:
		push_error("Failed to load map: " + newMapPath)
		newMapPath = ""

	elif status == ResourceLoader.THREAD_LOAD_IN_PROGRESS:
		print("Map loading in progress for: " + newMapPath)

	elif status == ResourceLoader.THREAD_LOAD_LOADED:
		newMapLoaded = true
		newMapReady()



func mapChange(map:String, playerDestinationNodeName:String) -> void:
	# Begin Loading new map
	newMapPath = map
	playerDestinationNodeName = playerDestinationNodeName
	ResourceLoader.load_threaded_request(newMapPath)

	# Begin fadeout
	hasFadedOut = false
	TRANSITION.fade(TransitionSingleton.FadeType.FADE_OUT)
	TRANSITION.fadeOutEnd.connect(onFadeOutEnd)

func onFadeOutEnd() -> void:
	# Fade out has occurred, are we still waiting for the map to load?
	TRANSITION.fadeOutEnd.disconnect(onFadeOutEnd)
	hasFadedOut = true

	# Make sure we aren't still waiting for the map to load.
	if !newMapLoaded:
		return
	newMapReady()

func newMapReady():
	if !hasFadedOut:
		return

	# Instantiate the new map
	var mapResource = ResourceLoader.load_threaded_get(newMapPath)
	if mapResource == null:
		push_error("Failed to load map resource: " + newMapPath)
		return
	
	# Stop tracking new map name
	newMapPath = ""

	# Emit event
	mapChanged.emit(mapResource, playerDestinationNodeName)

	# Begin Fade In
	TRANSITION.fade(TransitionSingleton.FadeType.FADE_IN)
	TRANSITION.fadeInEnd.connect(onFadeInEnd)

func onFadeInEnd() -> void:
	TRANSITION.fadeInEnd.disconnect(onFadeInEnd)