extends SceneTree

# Forgejo #225: the run survives being written to disk and read back.
#
# The interesting part is not "does it write a file" but whether the things
# JSON cannot hold survive: Vector2 positions, chunk coordinates used as
# dictionary KEYS, and Inventory objects nested inside the buildings array.
# Those are what a naive save silently flattens.
#
# Covers:
#   A. a rich run round-trips field for field
#   B. Vector2i dictionary keys come back as Vector2i, not as strings
#   C. inventories come back with their contents AND their capacity
#   D. a save from a newer build is refused, with a reason
#   E. a damaged file is refused rather than half-applied
#   F. a field the save predates keeps its new-game value

# Mirrored rather than read off SaveGame: a bare ClassName.CONST in a
# SceneTree script has broken method resolution for a whole file here before.
const TEST_PATH: String = "user://test_savegame.json"

var game_state: Node


func _initialize() -> void:
	game_state = root.get_node("GameState")


func _process(_delta: float) -> bool:
	game_state.buildings.clear()
	game_state.extractors.clear()
	game_state.reset_progression()
	game_state.reset_new_game()
	game_state.reset_quests()

	# --- a run with something in every awkward corner -------------------
	game_state.research_points = 42
	game_state.unlocked = ["shipyards", "coordination"]
	game_state.rocks = 1234
	game_state.fleet_position = Vector2(987.5, -321.25)
	game_state.wave_number = 7
	game_state.quest_index = 5
	game_state.explored_chunks[Vector2i(3, -4)] = true
	game_state.explored_chunks[Vector2i(-11, 0)] = true
	game_state.visited_planets["some-planet-id"] = true
	var b_id: int = game_state.add_building(GameState.BUILDING_TRANSPORT_HUB, Vector2(600.0, -150.0))
	var record: Dictionary = game_state.find_building(b_id)
	record.inventory.total_capacity = 88
	record.inventory.set_amount(GameState.RESOURCE_ORE, 17)
	game_state.fleet_inventory.set_amount(GameState.RESOURCE_GAS, 9)

	var before: Dictionary = _snapshot()

	if not SaveGame.save(game_state, TEST_PATH):
		return _fail("the run would not save")
	if not SaveGame.has_save(TEST_PATH):
		return _fail("saved, but has_save() cannot see the file")

	# Wipe it back to a fresh game, so a load that does nothing cannot pass.
	game_state.buildings.clear()
	game_state.extractors.clear()
	game_state.reset_progression()
	game_state.reset_new_game()
	game_state.reset_quests()
	game_state.explored_chunks.clear()
	if _snapshot() == before:
		return _fail("wiping the run changed nothing, so a load would prove nothing")

	var result: Dictionary = SaveGame.load_into(game_state, TEST_PATH)
	if not bool(result.get("ok", false)):
		return _fail("the run would not load back: %s" % result.get("reason", ""))

	# --- A. field for field ---------------------------------------------
	var after: Dictionary = _snapshot()
	for key in before:
		if after.get(key) != before[key]:
			return _fail("'%s' did not survive the round trip: %s -> %s" \
				% [key, before[key], after.get(key)])
	print("a run with %d fields round-tripped intact" % before.size())

	# --- B. chunk coordinates are still coordinates ----------------------
	if not game_state.explored_chunks.has(Vector2i(3, -4)):
		return _fail("chunk keys came back as something other than Vector2i: %s" \
			% str(game_state.explored_chunks.keys()))
	print("explored chunks came back keyed by Vector2i")

	# --- C. inventories keep contents and capacity -----------------------
	var loaded: Dictionary = game_state.find_building(b_id)
	if loaded.is_empty():
		return _fail("the transport hub did not come back")
	if int(loaded.inventory.amount(GameState.RESOURCE_ORE)) != 17:
		return _fail("the hub's ore did not survive: %d" % loaded.inventory.amount(GameState.RESOURCE_ORE))
	if int(loaded.inventory.total_capacity) != 88:
		return _fail("the hub's capacity did not survive: %d" % loaded.inventory.total_capacity)
	if int(game_state.fleet_inventory.amount(GameState.RESOURCE_GAS)) != 9:
		return _fail("the fleet hold's gas did not survive")
	print("inventories came back with their contents and their capacity")

	# --- D. a save from a newer build is refused --------------------------
	_rewrite_version(999)
	var newer: Dictionary = SaveGame.load_into(game_state, TEST_PATH)
	if bool(newer.get("ok", false)):
		return _fail("a save from a newer build loaded anyway")
	if not String(newer.get("reason", "")).to_lower().contains("newer"):
		return _fail("a newer save was refused without saying why: '%s'" % newer.get("reason", ""))
	print("a newer save is refused: %s" % newer.get("reason", ""))

	# --- E. a damaged file is refused, not half-applied -------------------
	var f: FileAccess = FileAccess.open(TEST_PATH, FileAccess.WRITE)
	f.store_string("{ this is not json")
	f.close()
	var marker: int = game_state.research_points
	var damaged: Dictionary = SaveGame.load_into(game_state, TEST_PATH)
	if bool(damaged.get("ok", false)):
		return _fail("a damaged save reported success")
	if game_state.research_points != marker:
		return _fail("a damaged save was partly applied before it failed")
	print("a damaged save is refused: %s" % damaged.get("reason", ""))

	# --- F. a field the save predates keeps its new-game value ------------
	# Adding progression must not invalidate every existing save, so a
	# missing field is left alone rather than cleared.
	SaveGame.save(game_state, TEST_PATH)
	_drop_field("research_points")
	game_state.research_points = 77
	var partial: Dictionary = SaveGame.load_into(game_state, TEST_PATH)
	if not bool(partial.get("ok", false)):
		return _fail("a save missing one field was refused entirely: %s" % partial.get("reason", ""))
	if game_state.research_points != 77:
		return _fail("a missing field was cleared instead of left alone (%d)" % game_state.research_points)
	print("a field the save predates keeps its current value")

	SaveGame.clear(TEST_PATH)
	print("TEST_SAVE_GAME: PASS")
	quit(0)
	return true


# The fields this test compares. Deliberately a hand-picked spread rather
# than SaveGame.FIELDS: comparing the list against itself would pass even if
# the codec dropped everything.
func _snapshot() -> Dictionary:
	return {
		"research_points": game_state.research_points,
		"unlocked": game_state.unlocked.duplicate(),
		"rocks": game_state.rocks,
		"fleet_position": game_state.fleet_position,
		"wave_number": game_state.wave_number,
		"quest_index": game_state.quest_index,
		"building_count": game_state.buildings.size(),
		"chunk_count": game_state.explored_chunks.size(),
		"visited": game_state.visited_planets.size(),
	}


func _rewrite_version(to: int) -> void:
	var file: FileAccess = FileAccess.open(TEST_PATH, FileAccess.READ)
	var data: Dictionary = JSON.parse_string(file.get_as_text())
	file.close()
	data["version"] = to
	file = FileAccess.open(TEST_PATH, FileAccess.WRITE)
	file.store_string(JSON.stringify(data))
	file.close()


func _drop_field(name: String) -> void:
	var file: FileAccess = FileAccess.open(TEST_PATH, FileAccess.READ)
	var data: Dictionary = JSON.parse_string(file.get_as_text())
	file.close()
	data["fields"].erase(name)
	file = FileAccess.open(TEST_PATH, FileAccess.WRITE)
	file.store_string(JSON.stringify(data))
	file.close()


func _fail(message: String) -> bool:
	print("TEST_SAVE_GAME: FAIL (%s)" % message)
	quit(1)
	return true