implement loading and saving raw data to save file resource

src/dev-util/savegame.gd

@@ -1,8 +1,69 @@
 @tool
 class_name SaveGame extends Resource
 
+@export var filepath: String
+@export var save_slot_id: int 
+@export var unique_save_name: String = "frame_of_mind_save_slot_%d_%s_%s" % [save_slot_id, Time.get_date_string_from_system(), Time.get_time_string_from_system()]
 @export var current_room: State.rooms = 0
 @export var mementos_complete: int = 0
-@export var board_state: PackedScene
+@export var board_state: Dictionary
-@export var thumbnail: Texture2D = preload("res://import/interface-elements/empty_save_slot.png")
+@export var thumbnail: Image = Image.load_from_file("res://import/interface-elements/empty_save_slot.png")
 @export var last_saved: Dictionary = Time.get_datetime_dict_from_system()
+
+@export var is_save_file_valid: bool = false
+
+func _init(filepath = "") -> void:
+	if filepath == "":
+		filepath = "usr://saves/%s" % unique_save_name
+		
+	read_save_file()
+
+func _get_save_dict() -> Dictionary:
+	return {
+		"save_slot_id": save_slot_id,
+		"unique_save_name": unique_save_name,
+		"current_room": current_room,
+		"mementos_complete": mementos_complete,
+		"board_state": board_state,
+		"last_saved": last_saved
+	}
+
+
+func read_save_file():
+	if FileAccess.file_exists("%s.json:" % filepath):
+		
+		
+		var file = FileAccess.open("%s.json:" % filepath, FileAccess.READ)
+		var raw_json = FileAccess.get_file_as_string("%s.json:" % filepath)
+		file.close()
+		var parsed: Dictionary = JSON.parse_string(raw_json)
+		
+		var tmp_img
+		if FileAccess.file_exists("%s.png" % filepath):
+			tmp_img = Image.load_from_file("%s.png" % filepath)
+		
+		is_save_file_valid = (
+				save_slot_id is int and
+				unique_save_name is String and
+				current_room is int and
+				mementos_complete is int and
+				board_state is Dictionary and
+				last_saved is Dictionary and
+				Time.get_unix_time_from_datetime_dict(last_saved) != 0 and 
+				tmp_img is Image
+			)
+		
+		if is_save_file_valid:
+			for key in parsed.keys():
+				set(key, parsed[key])
+		
+			thumbnail = tmp_img
+
+func save_file(current_screen: ImageTexture):
+	thumbnail = current_screen.get_image()
+	current_screen.resize(384, 261, Image.INTERPOLATE_LANCZOS)
+	
+	thumbnail.save_png("%s.png" % filepath)
+	
+	var file = FileAccess.open("%s.json:" % filepath, FileAccess.WRITE)
+	file.store_string(JSON.stringify(_get_save_dict()))

src/logic-scenes/main menu/save_game_display.gd

@@ -6,7 +6,7 @@ func _init(save: SaveGame, id: int) -> void:
 	add_child(base_container)
 	
 	var texture:= TextureRect.new()
-	texture.texture = save.thumbnail
+	texture.texture = ImageTexture.create_from_image(save.thumbnail)
 	texture.size_flags_vertical = Control.SIZE_SHRINK_CENTER
 	
 	base_container.add_child(texture)