extends CanvasLayer

const _preload_animation_name := "Preload"
const _postload_animation_name := "Postload"

var _is_loading := false
var _should_play_animation := false
var _progress_completion := []
var _scene_path: String
var _on_scene_loaded: Callable = func(_scene): pass
var _should_reset := false

@onready var _animator: AnimationPlayer = %animator
@onready var _progress_bar: ProgressBar = %progress_bar
@onready var _background: ColorRect = %background

func _ready():
	_background.visible = false
	_background.modulate = Color(1, 1, 1, 0)

func load_scene(
	path: String,
	use_transition_scene: bool = false,
	on_scene_loaded: Callable = func(_scene): pass) -> bool:
	if _is_loading:
		printerr("Scene loading is already in process")
		return false

	_is_loading = true
	_should_play_animation = use_transition_scene
	_on_scene_loaded = on_scene_loaded
	call_deferred("_deferred_load_scene", path)

	return true

func _process(_delta: float) -> void:
	if _should_reset: _reset()

	if _is_loading:
		var loading_status := ResourceLoader.load_threaded_get_status(
			_scene_path,
			_progress_completion)

		_progress_bar.value = _progress_completion[0]

		match loading_status:
			ResourceLoader.THREAD_LOAD_IN_PROGRESS:
				pass
			ResourceLoader.THREAD_LOAD_LOADED:
				_set_new_scene()
			ResourceLoader.THREAD_LOAD_FAILED:
				printerr("Scene loading failed")
				_is_loading = false

func _deferred_load_scene(path: String) -> void:
	_scene_path = path
	ResourceLoader.load_threaded_request(_scene_path)
	_try_play_animation(_preload_animation_name)

func _set_new_scene() -> void:
	get_tree().change_scene_to_packed(
		ResourceLoader.load_threaded_get(_scene_path))

	_try_play_animation(_postload_animation_name)
	_should_reset = true

func _reset() -> void:
	_on_scene_loaded.call(get_tree().current_scene)

	_is_loading = false
	_progress_completion[0] = 0.0
	_on_scene_loaded = func(_scene): pass
	_should_reset = false

func _try_play_animation(animation_name: String) -> void:
	if _should_play_animation:
		_animator.play(animation_name)