class_name DeckManager
extends RefCounted

## DeckManager - Handles deck persistence (save/load)

const DECKS_DIR = "user://decks/"


## Save a deck to file
## Returns true on success
static func save_deck(deck: Deck, filename: String) -> bool:
	# Ensure directory exists
	DirAccess.make_dir_recursive_absolute(DECKS_DIR)

	var path = DECKS_DIR + _sanitize_filename(filename) + ".json"
	var file = FileAccess.open(path, FileAccess.WRITE)
	if not file:
		push_error("DeckManager: Failed to open file for writing: " + path)
		return false

	var data = deck.to_dict()
	file.store_string(JSON.stringify(data, "\t"))
	file.close()
	return true


## Load a deck from file
## Returns null on failure
static func load_deck(filename: String) -> Deck:
	var path = DECKS_DIR + _sanitize_filename(filename) + ".json"

	if not FileAccess.file_exists(path):
		push_error("DeckManager: File not found: " + path)
		return null

	var file = FileAccess.open(path, FileAccess.READ)
	if not file:
		push_error("DeckManager: Failed to open file for reading: " + path)
		return null

	var json_text = file.get_as_text()
	file.close()

	var json = JSON.new()
	var error = json.parse(json_text)
	if error != OK:
		push_error("DeckManager: JSON parse error: " + json.get_error_message())
		return null

	var data = json.get_data()
	if not data is Dictionary:
		push_error("DeckManager: Invalid deck data format")
		return null

	var deck = Deck.new()
	deck.from_dict(data)
	return deck


## Delete a deck file
## Returns true on success
static func delete_deck(filename: String) -> bool:
	var path = DECKS_DIR + _sanitize_filename(filename) + ".json"

	if not FileAccess.file_exists(path):
		return false

	var dir = DirAccess.open(DECKS_DIR)
	if dir:
		return dir.remove(_sanitize_filename(filename) + ".json") == OK
	return false


## List all saved decks
## Returns array of deck names (without .json extension)
static func list_decks() -> Array[String]:
	var decks: Array[String] = []

	# Ensure directory exists
	DirAccess.make_dir_recursive_absolute(DECKS_DIR)

	var dir = DirAccess.open(DECKS_DIR)
	if not dir:
		return decks

	dir.list_dir_begin()
	var filename = dir.get_next()
	while filename != "":
		if not dir.current_is_dir() and filename.ends_with(".json"):
			decks.append(filename.trim_suffix(".json"))
		filename = dir.get_next()
	dir.list_dir_end()

	decks.sort()
	return decks


## Check if a deck exists
static func deck_exists(filename: String) -> bool:
	var path = DECKS_DIR + _sanitize_filename(filename) + ".json"
	return FileAccess.file_exists(path)


## Generate a unique deck name
static func generate_unique_name(base_name: String = "New Deck") -> String:
	var name = base_name
	var counter = 1

	while deck_exists(name):
		counter += 1
		name = "%s %d" % [base_name, counter]

	return name


## Sanitize filename to prevent path traversal
static func _sanitize_filename(filename: String) -> String:
	# Remove path separators and dangerous characters
	var sanitized = filename.replace("/", "_").replace("\\", "_")
	sanitized = sanitized.replace("..", "_").replace(":", "_")
	# Trim whitespace
	sanitized = sanitized.strip_edges()
	# Ensure not empty
	if sanitized.is_empty():
		sanitized = "deck"
	return sanitized