extends Object
class_name TopicData

signal topic_added(topic)
signal topic_inserted(topic, position)

const FILE_NAME = "topic_list.dat"

var dirty_flag = false
var loaded_topics = []


func add_topic(content, type): # On start-up.
	var topic = Topic.new()
	topic.content = content
	topic.type = type
	loaded_topics.append(topic)
	
	emit_signal("topic_added", topic)


func insert_topic(position: int):
	var topic = Topic.new()
	loaded_topics.append(topic)
	dirty_flag = true
	
	emit_signal("topic_inserted", topic, position)


func sort_topics():
	loaded_topics.sort_custom(self, "_compare_topic_index")


func _compare_topic_index(a, b):
	return a.associated_node.parent.get_index() < b.associated_node.parent.get_index()


func load_data():
	var file = File.new()
	if not file.file_exists("user://" + FILE_NAME):
		return
	file.open("user://" + FILE_NAME, File.READ)
	var json_string = file.get_as_text()
	if validate_json(json_string):
		printerr("\"" + FILE_NAME + "\" was found, but is corrupted.")
		return
	var topic_data_list = parse_json(json_string)
	for topic_data in topic_data_list:
		add_topic(
			topic_data["content"],
			int(topic_data["type"])
		)


func save_data():
	if dirty_flag:
		sort_topics() # Important before saving, to remain the order.
		var topic_data_list = []
		for topic in loaded_topics:
			var topic_data = {
				"content" : topic.content,
				"type" : topic.type
			}
			topic_data_list.append(topic_data)
		var json_string = to_json(topic_data_list)
		var file = File.new()
		file.open("user://" + FILE_NAME, File.WRITE)
		file.store_string(json_string)
		file.close()
	# dirty_flag needs to be set to false after successful save!
	dirty_flag = false