class_name SaveGame extends Resource

## Save game data container
## This is primarily a data class - file I/O helpers are thin wrappers around ResourceSaver/Loader


# === Data Fields ===

@export var unique_save_name: String = ""
@export var current_room: State.rooms = State.rooms.NULL
@export_flags("Intro", "Childhood", "Voice Training", "Jui Jutsu") var mementos_complete: int = 0
@export_flags_2d_physics var sequences_enabled: int = 63

# Board state - properly typed fields
@export var board_positions: Dictionary[StringName, Vector2] = {}  # Position of all cards and stickies
@export var board_attachments: Dictionary[StringName, StringName] = {}  # Sticky name → Card name (if attached)

## Scenes / Items / IDs that were seen
@export var seen : Array[StringName] = []

@export var childhood_board_complete: bool = false
@export var subway_burnout : bool = false

@export var player_position : Vector3 = Vector3.ZERO
@export var player_yaw : float = 0.0
@export var player_pitch : float = 0.0

@export var last_saved: int = 0

# === Computed Properties ===
var is_valid: bool:
	get: return _validate()

var current_room_path: String:
	get: return Main.room_paths[current_room] if Main else ""

var is_empty: bool:
	get: return not FileAccess.file_exists(file_name) or (current_room == State.rooms.NULL)

var completed_sequences: int:
	get:
		# Hamming weight (population count) algorithm for counting set bits
		var i: int = mementos_complete - ((mementos_complete >> 1) & 0x55555555)
		i = (i & 0x33333333) + ((i >> 2) & 0x33333333)
		i = (i + (i >> 4)) & 0x0F0F0F0F
		i *= 0x01010101
		return i >> 24

var total_connections: int:
	get:
		return board_attachments.size()

# === State Variables / External Data ===
## Where to save the savegame to / where it was loaded from
var file_name: String = ""

## Screenshot or placeholder image
var thumbnail: Texture = preload("res://import/interface-elements/empty_save_slot.png")

# === Static Helpers ===

## Generates a unique save filepath
static func generate_save_path() -> String:
	var timestamp := "%s_%s" % [Time.get_date_string_from_system(), Time.get_time_string_from_system().replace(":", "-")]
	var unique_name := "frame_of_mind_%s-%d" % [timestamp, randi()]
	return "%s/%s.tres" % [State.user_saves_path, unique_name]

## Creates a new save game with generated filepath
static func create_new() -> SaveGame:
	var save := SaveGame.new()
	save.file_name = generate_save_path()
	save.unique_save_name = save.file_name.get_file().get_basename()
	save.last_saved = int(Time.get_unix_time_from_system())

	# Ensure save directory exists
	if not DirAccess.dir_exists_absolute(save.file_name.get_base_dir()):
		DirAccess.make_dir_absolute(save.file_name.get_base_dir())

	print("SaveGame: Created new save: %s" % save.file_name)
	return save

## Loads an existing save from disk
static func load_from_file(save_filepath: String) -> SaveGame:
	if not FileAccess.file_exists(save_filepath):
		push_error("SaveGame: File does not exist: %s" % save_filepath)
		return null

	var loaded: SaveGame = ResourceLoader.load(save_filepath, "", ResourceLoader.CACHE_MODE_IGNORE)
	if not loaded:
		push_error("SaveGame: Failed to load resource from: %s" % save_filepath)
		return null

	# Update filepath metadata
	loaded.file_name = save_filepath
	loaded.unique_save_name = save_filepath.get_file().get_basename()

	# Load thumbnail (stored separately as PNG)
	_load_thumbnail(loaded)

	# Validate and return
	loaded.is_valid = loaded._validate()
	if not loaded.is_valid:
		push_error("SaveGame: Validation failed: %s" % save_filepath)
		return null

	return loaded

## Helper to load thumbnail from separate PNG file
static func _load_thumbnail(save: SaveGame) -> void:
	var thumbnail_path := "%s/thumbnails/%s.png" % [save.file_name.get_base_dir(), save.unique_save_name]
	if FileAccess.file_exists(thumbnail_path):
		var img := Image.load_from_file(thumbnail_path)
		if img:
			save.thumbnail = ImageTexture.create_from_image(img)

# === Instance Methods ===

## Captures current player position/rotation from State.player
func capture_player_state() -> void:
	if not State.player:
		return

	player_position = State.player.global_position
	var yaw: Node3D = State.player.get_node("Yaw")
	var pitch: Node3D = yaw.get_node("Pitch")
	player_yaw = yaw.rotation.y
	player_pitch = pitch.rotation.x

	print("SaveGame: Captured player state - pos: %s, yaw: %.2f, pitch: %.2f" % [player_position, player_yaw, player_pitch])

## Saves to disk with thumbnail
func save_to_file(screen_shot: Texture2D) -> void:
	if unique_save_name == "DEBUG":
		push_warning("SaveGame: DEBUG save skipped (intentional).")
		return

	assert(State.room, "Trying to save while not in a room.")
	assert(State.room.id != State.rooms.NULL, "Trying to save in a room that's not correctly initialized.")

	# Save game can track the room it is in by itself;
	# and we should never save before having successfully entered a room.
	current_room = State.room.id

	prints("-----------", "SAVE POINT", State.room, "-----------")
	print("SaveGame: Saving to file: %s" % file_name)

	# Capture current state
	capture_player_state()
	last_saved = int(Time.get_unix_time_from_system())

	# Save thumbnail
	_save_thumbnail(screen_shot)

	# Save resource
	var result := ResourceSaver.save(self, file_name)
	if result != OK:
		push_error("Failed to save resource to: %s (Error: %d)" % [file_name, result])
	else:
		print("Successfully saved to: %s" % file_name)

## Processes and saves thumbnail as PNG
func _save_thumbnail(screen_shot: Texture2D) -> void:
	var img: Image = screen_shot.get_image()
	img.convert(Image.FORMAT_RGB8)
	img.linear_to_srgb()
	img.resize(384, 216, Image.INTERPOLATE_LANCZOS)
	img.crop(384, 216)

	# Ensure thumbnails directory exists
	var save_dir := DirAccess.open(file_name.get_base_dir())
	if not save_dir.dir_exists("thumbnails"):
		save_dir.make_dir("thumbnails")

	var thumbnail_path := "%s/thumbnails/%s.png" % [file_name.get_base_dir(), unique_save_name]
	img.save_png(thumbnail_path)


# === Legacy Validation (may want to be removed) ===

func _validate() -> bool:
	return _validate_board_state()

func _validate_board_state() -> bool:
	# Validate positions
	for position in board_positions.values():
		if not position is Vector2:
			push_error("Save %s: Corrupted board positions" % unique_save_name)
			return false

	# Validate attachments (sticky must exist, card must exist)
	for sticky_name in board_attachments.keys():
		var card_name := board_attachments[sticky_name]
		if not board_positions.has(card_name):
			push_error("Save %s: Sticky '%s' attached to non-existent card '%s'" % [unique_save_name, sticky_name, card_name])
			return false

	return true