## Sprint 19 — Game session management (#258, D-085)
## Per-game save directories: created on New Game, resumed via game-id.
## SessionManager autoload: new_game(), resume_game(), list_game_dirs().
class_name TestSessionManagerSprint19
extends GdUnitTestSuite

const MAIN_MENU_SCENE = preload("res://scenes/main_menu.tscn")

# Game IDs created during the current test — deleted in after_test().
var _created_ids: Array = []


# ---------------------------------------------------------------------------
# Lifecycle
# ---------------------------------------------------------------------------

func before_test() -> void:
	GameState.current_game_id = ""
	_created_ids = []


func after_test() -> void:
	for game_id in _created_ids:
		var path := "user://saves/" + game_id
		DirAccess.remove_absolute(ProjectSettings.globalize_path(path))
	_created_ids.clear()
	GameState.current_game_id = ""


# ---------------------------------------------------------------------------
# Helper: call new_game() and track the created directory for cleanup.
# ---------------------------------------------------------------------------

func _new_game() -> String:
	var game_id := SessionManager.new_game()
	if not game_id.is_empty():
		_created_ids.append(game_id)
	return game_id


# ---------------------------------------------------------------------------
# GameState.current_game_id field
# ---------------------------------------------------------------------------

func test_current_game_id_field_exists() -> void:
	## D-085: GameState must have current_game_id field.
	assert_bool(GameState.has("current_game_id")).override_failure_message(
		"GameState must have 'current_game_id' field (D-085 #258)"
	).is_true()


func test_current_game_id_default_is_empty_string() -> void:
	## Before any session starts, current_game_id is empty.
	GameState.current_game_id = ""
	assert_str(GameState.current_game_id).override_failure_message(
		"GameState.current_game_id default must be empty string"
	).is_empty()


# ---------------------------------------------------------------------------
# SessionManager autoload exists
# ---------------------------------------------------------------------------

func test_session_manager_autoload_exists() -> void:
	## SessionManager must be registered as an autoload.
	var sm := Engine.get_singleton("SessionManager")
	assert_that(sm != null).override_failure_message(
		"SessionManager must be registered as autoload in project.godot (#258)"
	).is_true()


# ---------------------------------------------------------------------------
# new_game() — game-id format and GameState update
# ---------------------------------------------------------------------------

func test_new_game_returns_non_empty_string() -> void:
	var game_id := _new_game()
	assert_str(game_id).override_failure_message(
		"SessionManager.new_game() must return a non-empty game-id string"
	).is_not_empty()


func test_new_game_sets_current_game_id_on_gamestate() -> void:
	var game_id := _new_game()
	assert_str(GameState.current_game_id).override_failure_message(
		"new_game() must set GameState.current_game_id"
	).is_equal(game_id)


func test_new_game_id_format_has_two_dashes() -> void:
	## Format: <YYYYMMDD>-<HHMMSS>-<hex6> — two separator dashes.
	var game_id := _new_game()
	var parts := game_id.split("-")
	assert_int(parts.size()).override_failure_message(
		"game-id must have format <YYYYMMDD>-<HHMMSS>-<hex6> (3 parts separated by '-')"
	).is_equal(3)


func test_new_game_id_first_part_is_8_digits() -> void:
	## First part is YYYYMMDD — 8 decimal digits.
	var game_id := _new_game()
	var parts := game_id.split("-")
	assert_int(parts[0].length()).override_failure_message(
		"game-id first part (date) must be 8 characters (YYYYMMDD)"
	).is_equal(8)


func test_new_game_id_second_part_is_6_digits() -> void:
	## Second part is HHMMSS — 6 decimal digits.
	var game_id := _new_game()
	var parts := game_id.split("-")
	assert_int(parts[1].length()).override_failure_message(
		"game-id second part (time) must be 6 characters (HHMMSS)"
	).is_equal(6)


func test_new_game_id_third_part_is_6_hex_chars() -> void:
	## Third part is 6 hex characters (RNG seed).
	var game_id := _new_game()
	var parts := game_id.split("-")
	assert_int(parts[2].length()).override_failure_message(
		"game-id third part (hex seed) must be 6 characters"
	).is_equal(6)


func test_new_game_ids_are_unique() -> void:
	## Two rapid new_game() calls should produce different IDs
	## (different RNG seeds; same-second timestamps are valid but seeds differ).
	var id1 := _new_game()
	var id2 := _new_game()
	# Check that hex seeds differ (they almost certainly will)
	var seed1 := id1.split("-")[2]
	var seed2 := id2.split("-")[2]
	assert_str(seed1).override_failure_message(
		"Successive new_game() calls should have different RNG seeds"
	).is_not_equal(seed2)


# ---------------------------------------------------------------------------
# resume_game() — sets GameState.current_game_id
# ---------------------------------------------------------------------------

func test_resume_game_sets_current_game_id() -> void:
	var test_id := "20260225-143022-a7b3f1"
	SessionManager.resume_game(test_id)
	assert_str(GameState.current_game_id).override_failure_message(
		"resume_game() must set GameState.current_game_id to the given id"
	).is_equal(test_id)


func test_resume_game_overwrites_previous_game_id() -> void:
	SessionManager.resume_game("20260225-100000-aabbcc")
	SessionManager.resume_game("20260225-120000-112233")
	assert_str(GameState.current_game_id).is_equal("20260225-120000-112233")


# ---------------------------------------------------------------------------
# Main menu scene
# ---------------------------------------------------------------------------

func test_main_menu_scene_exists() -> void:
	assert_bool(ResourceLoader.exists("res://scenes/main_menu.tscn")).override_failure_message(
		"Main menu scene must exist at res://scenes/main_menu.tscn (#258)"
	).is_true()


func test_main_menu_instantiates_without_crash() -> void:
	if not ResourceLoader.exists("res://scenes/main_menu.tscn"):
		push_warning("TestSessionManagerSprint19: main_menu.tscn not found — skip")
		return
	var scene: Node = MAIN_MENU_SCENE.instantiate()
	auto_free(scene)
	add_child(scene)
	assert_that(scene).is_not_null()


func test_main_menu_has_new_game_button() -> void:
	if not ResourceLoader.exists("res://scenes/main_menu.tscn"):
		return
	var scene: Node = MAIN_MENU_SCENE.instantiate()
	auto_free(scene)
	add_child(scene)
	var btn := scene.get_node_or_null("VBox/NewGameBtn")
	assert_that(btn != null).override_failure_message(
		"Main menu must have VBox/NewGameBtn (#258)"
	).is_true()


func test_main_menu_has_continue_button() -> void:
	if not ResourceLoader.exists("res://scenes/main_menu.tscn"):
		return
	var scene: Node = MAIN_MENU_SCENE.instantiate()
	auto_free(scene)
	add_child(scene)
	var btn := scene.get_node_or_null("VBox/ContinueBtn")
	assert_that(btn != null).override_failure_message(
		"Main menu must have VBox/ContinueBtn (#258)"
	).is_true()


# ---------------------------------------------------------------------------
# Project main scene changed to main_menu.tscn
# ---------------------------------------------------------------------------

func test_project_main_scene_is_main_menu() -> void:
	## D-085: project boots to main menu, not directly to game scene.
	var scene_path: String = ProjectSettings.get_setting("application/run/main_scene", "")
	assert_str(scene_path).override_failure_message(
		"project.godot run/main_scene must be res://scenes/main_menu.tscn (#258)"
	).is_equal("res://scenes/main_menu.tscn")