feat: add validated quicksave persistence

main.tscn

@@ -8,6 +8,7 @@
 [ext_resource type="Script" uid="uid://cjvbgqx8rao0t" path="res://world/ui/ui.gd" id="6_7mycd"]
 [ext_resource type="PackedScene" uid="uid://dvd3qjpjor4sq" path="res://world/resource_nodes/ResourceNode.tscn" id="8_r3s0u"]
 [ext_resource type="Script" uid="uid://bbwol3mrjgn2x" path="res://world/active_world_adapter.gd" id="9_adapter"]
+[ext_resource type="Script" path="res://simulation/persistence/SaveSlotController.gd" id="10_save"]
 
 [sub_resource type="NavigationMesh" id="NavigationMesh_lquwl"]
 vertices = PackedVector3Array(-14.5, 0.5, 0, -1, 0.5, 0, -1, 0.5, -0.75, 0, 0.5, -1, 0, 0.5, -14.5, -14.5, 0.5, -14.5, 0.75, 0.5, -1, 0.75, 0.75, -0.5, 14.5, 0.5, -0.5, 14.5, 0.5, -14.5, 0.75, 0.75, 0, 0, 1, 0, 0, 0.75, 0.75, -0.5, 0.75, 0.75, -0.5, 0.5, 14.5, 14.5, 0.5, 14.5, -1, 0.5, 0.75, -14.5, 0.5, 14.5)
@@ -115,6 +116,10 @@ pantry_marker = NodePath("../ActivityMarkers/PantryMarker")
 script = ExtResource("3_lquwl")
 active_world_adapter = NodePath("../ActiveWorldAdapter")
 
+[node name="SaveSlotController" type="Node" parent="." node_paths=PackedStringArray("simulation_manager")]
+script = ExtResource("10_save")
+simulation_manager = NodePath("../SimulationManager")
+
 [node name="WorldViewManager" type="Node" parent="." unique_id=763982891 node_paths=PackedStringArray("simulation_manager", "active_npcs_parent")]
 script = ExtResource("4_1bvp3")
 npc_visual_scene = ExtResource("5_lquwl")

simulation/SimulationManager.gd

@@ -11,6 +11,7 @@ signal npc_target_requested(npc: SimNPC)
 signal npc_travel_requested(npc: SimNPC, target_position: Vector3)
 signal npc_inventory_changed(npc: SimNPC, item_id: StringName, amount: float)
 signal economic_event_recorded(event: EconomicEventRecord)
+signal state_restored
 
 var village := SimVillage.new()
 
@@ -749,4 +750,5 @@ func restore_state(record: SimulationStateRecord) -> bool:
 	register_loaded_resource_nodes()
 
 	village_changed.emit(village)
+	state_restored.emit()
 	return true

simulation/persistence/SaveSlotController.gd

@@ -0,0 +1,21 @@
+extends Node
+
+@export var simulation_manager: Node
+
+var store := SaveSlotStore.new()
+
+func _unhandled_key_input(event: InputEvent) -> void:
+	if not event.pressed or event.echo:
+		return
+	if event.keycode == KEY_F5:
+		if store.save(simulation_manager):
+			print("[SaveSlot] Quicksave written")
+		else:
+			push_error("[SaveSlot] " + store.last_error)
+		get_viewport().set_input_as_handled()
+	elif event.keycode == KEY_F9:
+		if store.load_into(simulation_manager):
+			print("[SaveSlot] Quicksave restored")
+		else:
+			push_error("[SaveSlot] " + store.last_error)
+		get_viewport().set_input_as_handled()

simulation/persistence/SaveSlotController.gd.uid

@@ -0,0 +1 @@
+uid://cwvdljsh148wh

simulation/persistence/SaveSlotStore.gd

@@ -0,0 +1,131 @@
+class_name SaveSlotStore
+extends RefCounted
+
+const DEFAULT_DIRECTORY := "user://saves"
+const DEFAULT_SLOT := "quicksave"
+const MAX_SAVE_BYTES := 16 * 1024 * 1024
+
+var save_directory: String
+var last_error := ""
+
+func _init(directory: String = DEFAULT_DIRECTORY) -> void:
+	save_directory = directory
+
+func save(manager: Node, slot_name: String = DEFAULT_SLOT) -> bool:
+	last_error = ""
+	if manager == null or not manager.has_method("serialize_state"):
+		return _fail("Save source cannot serialize simulation state")
+	if not _is_valid_slot_name(slot_name):
+		return _fail("Invalid save slot name")
+
+	var json_text: String = manager.serialize_state()
+	if json_text.to_utf8_buffer().size() > MAX_SAVE_BYTES:
+		return _fail("Save exceeds the supported size limit")
+	if SimulationStateRecord.from_json(json_text) == null:
+		return _fail("Simulation produced an invalid save record")
+	if not _ensure_directory():
+		return false
+
+	var final_path := get_slot_path(slot_name)
+	var temporary_path := final_path + ".tmp"
+	var backup_path := final_path + ".bak"
+	_remove_if_present(temporary_path)
+
+	var file := FileAccess.open(temporary_path, FileAccess.WRITE)
+	if file == null:
+		return _fail("Could not open temporary save file")
+	file.store_string(json_text)
+	file.flush()
+	file.close()
+	if _read_record(temporary_path) == null:
+		_remove_if_present(temporary_path)
+		return _fail("Temporary save failed validation")
+
+	var had_existing := FileAccess.file_exists(final_path)
+	if had_existing:
+		_remove_if_present(backup_path)
+		if DirAccess.rename_absolute(final_path, backup_path) != OK:
+			_remove_if_present(temporary_path)
+			return _fail("Could not preserve the previous save")
+	if DirAccess.rename_absolute(temporary_path, final_path) != OK:
+		if had_existing:
+			DirAccess.rename_absolute(backup_path, final_path)
+		_remove_if_present(temporary_path)
+		return _fail("Could not install the new save")
+	_remove_if_present(backup_path)
+	return true
+
+func load_into(manager: Node, slot_name: String = DEFAULT_SLOT) -> bool:
+	last_error = ""
+	if manager == null or not manager.has_method("restore_state"):
+		return _fail("Save target cannot restore simulation state")
+	if not _is_valid_slot_name(slot_name):
+		return _fail("Invalid save slot name")
+
+	var final_path := get_slot_path(slot_name)
+	var record := _read_record(final_path)
+	if record == null:
+		record = _read_record(final_path + ".bak")
+	if record == null:
+		return _fail("Save slot is missing, invalid, or unsupported")
+	if not bool(manager.restore_state(record)):
+		return _fail("Simulation refused the validated save record")
+	return true
+
+func has_slot(slot_name: String = DEFAULT_SLOT) -> bool:
+	if not _is_valid_slot_name(slot_name):
+		return false
+	var final_path := get_slot_path(slot_name)
+	return (
+		_read_record(final_path) != null
+		or _read_record(final_path + ".bak") != null
+	)
+
+func delete_slot(slot_name: String = DEFAULT_SLOT) -> bool:
+	if not _is_valid_slot_name(slot_name):
+		return false
+	var final_path := get_slot_path(slot_name)
+	_remove_if_present(final_path)
+	_remove_if_present(final_path + ".tmp")
+	_remove_if_present(final_path + ".bak")
+	return true
+
+func get_slot_path(slot_name: String = DEFAULT_SLOT) -> String:
+	return save_directory.path_join(slot_name + ".json")
+
+func _read_record(path: String) -> SimulationStateRecord:
+	if not FileAccess.file_exists(path):
+		return null
+	var file := FileAccess.open(path, FileAccess.READ)
+	if file == null:
+		return null
+	if file.get_length() > MAX_SAVE_BYTES:
+		file.close()
+		return null
+	var json_text := file.get_as_text()
+	file.close()
+	return SimulationStateRecord.from_json(json_text)
+
+func _ensure_directory() -> bool:
+	var absolute_directory := ProjectSettings.globalize_path(save_directory)
+	var error := DirAccess.make_dir_recursive_absolute(absolute_directory)
+	if error != OK and error != ERR_ALREADY_EXISTS:
+		return _fail("Could not create the save directory")
+	return true
+
+func _is_valid_slot_name(slot_name: String) -> bool:
+	if slot_name.is_empty() or slot_name.length() > 32:
+		return false
+	var allowed := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-"
+	for character in slot_name:
+		if not allowed.contains(character):
+			return false
+	return true
+
+func _remove_if_present(path: String) -> void:
+	if FileAccess.file_exists(path):
+		DirAccess.remove_absolute(path)
+
+func _fail(message: String) -> bool:
+	last_error = message
+	return false

simulation/persistence/SaveSlotStore.gd.uid

@@ -0,0 +1 @@
+uid://3w3wsbtr4gpw

tests/npc_visual_lifecycle_test.gd

@@ -99,6 +99,23 @@ func _run() -> void:
 		"Active position callback should synchronize simulation state"
 	)
 
+	var saved_state: String = manager.serialize_state()
+	var visual_before_restore: Node3D = view.active_npc_visuals[npc.id]
+	npc.hunger = 99.0
+	_check(
+		manager.restore_state_from_json(saved_state),
+		"Visual lifecycle scenario should restore valid state"
+	)
+	var visual_after_restore: Node3D = view.active_npc_visuals[npc.id]
+	_check(
+		visual_after_restore != visual_before_restore,
+		"State restoration should rebuild active NPC presentation"
+	)
+	_check(
+		visual_after_restore.global_position.is_equal_approx(npc.position),
+		"Rebuilt presentation should use the restored authoritative position"
+	)
+
 	if failures.is_empty():
 		print("[TEST] NPC visual lifecycle passed")
 		quit(0)

tests/save_slot_persistence_test.gd

@@ -0,0 +1,75 @@
+extends SceneTree
+
+var failures: Array[String] = []
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+func _run() -> void:
+	var test_directory := "user://save_slot_test_%s" % Time.get_ticks_usec()
+	var store := SaveSlotStore.new(test_directory)
+	var manager: Node = load("res://simulation/SimulationManager.gd").new()
+	manager.debug_logs = false
+	root.add_child(manager)
+	manager.set_process(false)
+
+	for step in 8:
+		manager.simulate_tick()
+	var saved_checksum: String = manager.get_state_checksum()
+	_check(store.save(manager), "A valid simulation should save atomically")
+	_check(store.has_slot(), "The validated quicksave should be discoverable")
+
+	for step in 5:
+		manager.simulate_tick()
+	_check(
+		manager.get_state_checksum() != saved_checksum,
+		"The scenario should change after the save point"
+	)
+	_check(store.load_into(manager), "A valid quicksave should load")
+	_check(
+		manager.get_state_checksum() == saved_checksum,
+		"Loading should restore the exact saved simulation"
+	)
+
+	var final_path := store.get_slot_path()
+	var backup_path := final_path + ".bak"
+	_check(
+		DirAccess.rename_absolute(final_path, backup_path) == OK,
+		"Test should reproduce the atomic replacement recovery window"
+	)
+	_check(
+		store.load_into(manager),
+		"A preserved previous save should recover an interrupted replacement"
+	)
+	_check(
+		DirAccess.rename_absolute(backup_path, final_path) == OK,
+		"Test should restore the primary save path"
+	)
+
+	var unchanged_checksum: String = manager.get_state_checksum()
+	var file := FileAccess.open(final_path, FileAccess.WRITE)
+	file.store_string("{\"schema\":\"broken\"}")
+	file.close()
+	_check(not store.load_into(manager), "Invalid save data should be rejected")
+	_check(
+		manager.get_state_checksum() == unchanged_checksum,
+		"A rejected save must not partially mutate the simulation"
+	)
+	_check(
+		not store.save(manager, "../escape"),
+		"Slot names must not escape the save directory"
+	)
+
+	store.delete_slot()
+	DirAccess.remove_absolute(ProjectSettings.globalize_path(test_directory))
+	if failures.is_empty():
+		print("[TEST] Save-slot persistence passed")
+		quit(0)
+		return
+	for failure in failures:
+		push_error("[TEST] " + failure)
+	quit(1)
+
+func _check(condition: bool, message: String) -> void:
+	if not condition:
+		failures.append(message)

tests/save_slot_persistence_test.gd.uid

@@ -0,0 +1 @@
+uid://c7ow4dj42sfhl

world/world_view_manager.gd

@@ -41,6 +41,10 @@ func initialize_world_view() -> void:
 		push_error(
 			"WorldViewManager: SimulationManager has no npc_inventory_changed signal"
 		)
+	if simulation_manager.has_signal("state_restored"):
+		simulation_manager.state_restored.connect(_on_simulation_state_restored)
+	else:
+		push_error("WorldViewManager: SimulationManager has no state_restored signal")
 	spawn_initial_npcs()
 
 func spawn_initial_npcs() -> void:
@@ -180,3 +184,9 @@ func _on_npc_inventory_changed(
 		push_error(
 			"WorldViewManager: NPCVisual has no set_carried_food_visible method"
 		)
+
+func _on_simulation_state_restored() -> void:
+	for visual in active_npc_visuals.values():
+		visual.queue_free()
+	active_npc_visuals.clear()
+	spawn_initial_npcs()