extends Node

enum VNLoadSource {
	NEW_GAME = 300,
	FROM_MANUAL_SAVE = 301,
	FROM_AUTOSAVE = 302,
}

enum VNSaveTarget {
	MANUAL_SAVE = 401,
	AUTOSAVE = 402,
}

const GLOBAL_DATA_PATH = "user://data.json"
const SAVES_DIR = "user://saves"
const MAX_SAVES = 24

signal loaded
signal updated_save_files(save_file_list)
signal new_manual_save(save_file)
signal new_autosave(save_file)

var has_loaded = false
var can_continue = false
var current_load_source: VNLoadSource = VNLoadSource.NEW_GAME
var current_load_path = ""
var current_load_file = null
var save_files = []
var global_data = null

var new_game_save_file = {}

func _ready():
	DirAccess.make_dir_recursive_absolute(SAVES_DIR)

	# Populate previously saved files
	for file_name in DirAccess.get_files_at(SAVES_DIR):
		if file_name.length() == 7 and file_name.right(5) == ".json":
			can_continue = true
			var path = "%s/%s" % [SAVES_DIR, file_name]
			var file = FileAccess.open(path, FileAccess.READ)
			var data = JSON.parse_string(file.get_as_text())
			file.close()
			save_files.append({
				"idx": int(file_name.left(2)),
				"path": path,
				"timestamp": data["timestamp"],
				"name": data["name"],
				"is_autosave": data.get("is_autosave", false),
			})
	save_files.sort_custom(func (a, b): return Time.get_unix_time_from_datetime_string(a["timestamp"]) > Time.get_unix_time_from_datetime_string(b["timestamp"]))

	has_loaded = true
	loaded.emit()

func create_save_file(target: VNSaveTarget, data: Variant, save_name: String = "") -> String:
	var timestamp = Time.get_datetime_string_from_system(false, true)
	var idx = 1
	var path = ""
	var is_autosave = target == VNSaveTarget.AUTOSAVE
	can_continue = true

	if save_files.size() > 0:
		idx = save_files[0]["idx"] % 99 + 1 # Avoid creating a 00.json file
	path = "%s/%02d.json" % [SAVES_DIR, idx]
	for i in range(save_files.size() - 1, -1, -1):
		# Remove file if MAX_SAVES limit would be exceeded or if "idx" wraps around and overwrites this
		if i >= MAX_SAVES - 1 or save_files[i]["idx"] == idx:
			# Should be safe to remove, since we're resizing from the right
			var save_to_delete = save_files.pop_at(i)
			DirAccess.remove_absolute(save_to_delete["path"])

	var file = FileAccess.open(path, FileAccess.WRITE)
	file.store_string(JSON.stringify({
		"timestamp": timestamp,
		"name": save_name,
		"is_autosave": is_autosave,
		"data": data,
	}))
	file.close()
	save_files.push_front({
		"idx": idx,
		"path": path,
		"timestamp": timestamp,
		"name": save_name,
		"is_autosave": is_autosave,
	})
	match target:
		VNSaveTarget.MANUAL_SAVE:
			new_manual_save.emit(save_files[0])
		VNSaveTarget.AUTOSAVE:
			new_autosave.emit(save_files[0])
		_:
			assert(false, "Unknown save target %s" % target)
	return path

func load_save_file(load_target: VNLoadSource, load_file = null) -> Variant:
	current_load_source = load_target
	match load_target:
		VNLoadSource.NEW_GAME:
			return new_game_save_file
		#VNLoadSource.FROM_MANUAL_SAVE when not load_file:
		#	current_load_source = VNLoadSource.FROM_AUTOSAVE
		VNLoadSource.FROM_AUTOSAVE:
			current_load_path = load_file["path"]
		VNLoadSource.FROM_MANUAL_SAVE:
			current_load_path = load_file["path"]
		_:
			assert(false, "Can't figure out where to load saved data from!")
	if not FileAccess.file_exists(current_load_path):
		push_warning("Load file not found, returning new game data...")
		current_load_path = ""
		current_load_source = VNLoadSource.NEW_GAME
		return {}
	return JSON.parse_string(FileAccess.open(current_load_path, FileAccess.READ).get_as_text())["data"]

func delete_save_file(load_file = null):
	var i = save_files.find(load_file)
	if i == -1:
		push_warning("Couldn't locate file for deletion!")
		return
	DirAccess.remove_absolute(load_file["path"])
	save_files.remove_at(i)
	updated_save_files.emit(save_files)

func set_global_data(key: String, value: Variant):
	if FileAccess.file_exists(GLOBAL_DATA_PATH):
		var file = FileAccess.open(GLOBAL_DATA_PATH, FileAccess.READ)
		global_data = JSON.parse_string(file.get_as_text())
		file.close()
	elif not global_data:
		global_data = {}
	var prev_value = global_data.get(key)
	global_data[key] = value
	if value != prev_value:
		var file = FileAccess.open(GLOBAL_DATA_PATH, FileAccess.WRITE)
		file.store_string(JSON.stringify(global_data))
		file.close()
	return prev_value

func get_global_data(key: String, default = null):
	if not global_data:
		if FileAccess.file_exists(GLOBAL_DATA_PATH):
			var file = FileAccess.open(GLOBAL_DATA_PATH, FileAccess.READ)
			global_data = JSON.parse_string(file.get_as_text())
			file.close()
		else:
			global_data = {}
	return global_data.get(key, default)