extends SceneTree
## Save/load round trip: play a bit (chop a tree, mine a boulder, pick
## something up, build a workbench + chest with items in it, walk somewhere),
## save, throw the world away, load it fresh and check everything came back.
## Also covers world slots (create/list/delete) and a seed being honoured.
##
## Uses its own folder (user://test_worlds) so real saves are never touched.
## Run: godot --headless --path . --script res://tests/test_save_load.gd

var _fails := 0
var _finished := false
var A: Node    # Actions
var S: Node    # Saves
var DB: Node   # ItemDB

func check(cond: bool, what: String) -> void:
	print(("  ok   " if cond else "  FAIL ") + what)
	if not cond:
		_fails += 1

func _initialize() -> void:
	_run.call_deferred()

func _spawn_world() -> Node3D:
	var w: Node3D = load("res://scenes/world.tscn").instantiate()
	root.add_child(w)
	for _i in range(5):
		await physics_frame
	return w

func _run() -> void:
	A = root.get_node("Actions")
	S = root.get_node("Saves")
	DB = root.get_node("ItemDB")
	S.root_dir = "user://test_worlds"
	for w in S.list_worlds():
		S.delete_world(w.id)

	print("slots")
	var id: String = S.create_world("Test Island", 4242)
	var id2: String = S.create_world("Test Island", 7)
	check(id != id2, "two worlds with the same name get different ids (%s, %s)" % [id, id2])
	check(S.list_worlds().size() == 2, "both worlds are listed")
	S.delete_world(id2)
	check(S.list_worlds().size() == 1, "deleting a world removes it")
	S.current_id = id

	print("play + save")
	var world: Node3D = await _spawn_world()
	var terrain: Node3D = world.get_node("Terrain")
	check(terrain.noise_seed == 4242, "world generated from its saved seed")
	var player: CharacterBody3D = world.get_node("Player")
	var inv: Inventory = player.inventory
	var props: Node3D = world.get_node("Props")

	inv.add("stone_axe", 1); inv.add("stone_pickaxe", 1)
	var tree := _nearest(world, player, "tree")
	player.global_position = tree.global_position + Vector3(1.5, 0.2, 0)
	_hold(player, "stone_axe")
	while not tree.depleted:
		A.harvest_hit(player, tree, tree.global_position)
	var tree_uid: String = tree.uid
	var rock := _nearest(world, player, "rock")
	var rock_uid: String = rock.uid
	player.global_position = rock.global_position + Vector3(2.0, 0.5, 0)
	_hold(player, "stone_pickaxe")
	A.harvest_hit(player, rock, rock.global_position)
	A.harvest_hit(player, rock, rock.global_position)
	var rock_hp: float = rock.hp
	var pk_uid: String = props.pickups.keys()[0]
	var pk: Node3D = props.pickups[pk_uid]
	player.global_position = pk.global_position + Vector3(0.4, 0.4, 0)
	A.pickup(player, pk)

	inv.add("workbench", 1); inv.add("chest", 1); inv.add("wood", 33)
	var spot := Vector3(player.global_position.x + 3.0, 0, player.global_position.z)
	spot.y = terrain.sample_height(spot.x, spot.z)
	world.spawn_piece(DB.get_item("workbench"), Transform3D(Basis(Vector3.UP, 0.7), spot))
	var chest: Node = world.spawn_piece(DB.get_item("chest"), Transform3D(Basis(), spot + Vector3(0, 0, 3)))
	chest.inventory.add("flint", 7)
	chest.inventory.add("wood", 12)
	player.global_position = Vector3(5.0, terrain.sample_height(5.0, 6.0) + 1.0, 6.0)
	player.rotation.y = 1.25
	player.select(3)
	var wood_before := inv.count("wood")
	var pos_before := player.global_position
	check(world.save_now(), "save_now() succeeded")
	check(FileAccess.file_exists(S.root_dir.path_join(id).path_join("world.json")), "world.json written")

	world.queue_free()
	await process_frame
	await process_frame

	print("load")
	world = await _spawn_world()
	player = world.get_node("Player")
	inv = player.inventory
	props = world.get_node("Props")
	check(player.global_position.distance_to(pos_before) < 0.6, "player back where they saved (%.2f m off)" % player.global_position.distance_to(pos_before))
	check(absf(player.rotation.y - 1.25) < 0.01 and player.selected == 3, "facing and hotbar slot restored")
	check(inv.count("wood") == wood_before and inv.count("stone_axe") == 1, "inventory restored")
	check(props.resource_nodes[tree_uid].depleted, "felled tree is still a stump")
	var r = props.resource_nodes[rock_uid]
	check(is_instance_valid(r) and absf(r.hp - rock_hp) < 0.01, "half-mined boulder kept its damage")
	var pk2 = props.pickups[pk_uid]
	check(not is_instance_valid(pk2) or pk2.taken, "picked-up item stays picked up")
	var benches := 0
	var chest2: Node = null
	for p in world.get_node("Pieces").get_children():
		if p.item_id == "workbench":
			benches += 1
		elif p.item_id == "chest":
			chest2 = p
	check(benches == 1, "workbench rebuilt")
	check(chest2 != null and chest2.inventory.count("flint") == 7 and chest2.inventory.count("wood") == 12, "chest rebuilt with its contents")
	check(S.read_meta(id).play_time >= 0.0, "meta updated")

	_finished = true
	world.queue_free()
	S.delete_world(id)
	DirAccess.remove_absolute(S.root_dir)
	check(_finished, "test ran to the end (no script errors)")
	print("RESULT: %s (%d failures)" % ["PASS" if _fails == 0 else "FAIL", _fails])
	quit(1 if _fails > 0 else 0)

func _hold(player: Node, id: String) -> void:
	var inv: Inventory = player.inventory
	for i in range(inv.size()):
		var s = inv.get_slot(i)
		if s != null and s.id == id:
			var tmp = inv.get_slot(0)
			inv.set_slot(0, s)
			inv.set_slot(i, tmp)
			break
	player.select(0)

func _nearest(world: Node, player: Node3D, kind: String) -> Node3D:
	var best: Node3D = null
	var bd := INF
	for n in world.get_tree().get_nodes_in_group("harvestable"):
		if n.kind == kind and not n.depleted:
			var d := player.global_position.distance_to(n.global_position)
			if d < bd:
				bd = d
				best = n
	return best