extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_asteroid_mining.gd
# Asteroids used to be pure hazard - the only thing one could ever do was cost
# you a ship. They can now be shot apart for the ore inside, which is the one
# resource reachable in open space without conquering anything.
#
# Covers:
#   A. an asteroid survives a hit it should survive, so "destructible" does
#      not mean "evaporates on contact with anything"
#   B. enough fire destroys it and leaves ore behind
#   C. the ore is fetchable - flying a ship over it loads the fleet's hold,
#      which is the whole point of dropping it
#   D. ramming destroys the asteroid but yields NOTHING. Without that split a
#      shield vessel could farm asteroids by flying into them
#   E. dropped ore expires if nobody collects it, so a field that gets shot up
#      and abandoned cannot leak nodes for the rest of the session; a
#      hand-placed surface rock still lives forever

var game_state: Node
var main: Node
var fleet: Node
var asteroid: Node2D
var stage: int = 0
var elapsed: float = 0.0
var hold_before: int = 0


func _initialize() -> void:
	game_state = root.get_node("GameState")
	game_state.buildings.clear()
	game_state.extractors.clear()
	game_state.reset_progression()
	main = load("res://world/Main.tscn").instantiate()
	root.add_child(main)
	current_scene = main
	fleet = main.get_node("Fleet")


func _spawn_asteroid(at: Vector2) -> Node2D:
	var rock: Node2D = load("res://world/Asteroid.tscn").instantiate()
	rock.position = at
	main.add_child(rock)
	return rock


func _clear_sky() -> void:
	for node in get_nodes_in_group("asteroids") + get_nodes_in_group("rocks") \
			+ get_nodes_in_group("enemies") + get_nodes_in_group("player_projectiles"):
		if is_instance_valid(node):
			node.free()


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if elapsed < 0.3:
				return false
			main.get_node("EnemySpawner").set_process(false)
			main.get_node("AsteroidField").set_process(false)
			_clear_sky()
			fleet.spawn_ships(1, Vector2.ZERO, PackedStringArray([GameState.VESSEL_INTERCEPTOR]))

			# --- A/B. it takes real damage, then breaks -------------------
			asteroid = _spawn_asteroid(Vector2(4000.0, 0.0))
			var hit_points: int = int(asteroid.hp)
			if hit_points < 2:
				return _fail("an asteroid dies to a single point of damage, so there is nothing to survive")
			for i in range(hit_points - 1):
				asteroid.take_damage(1)
			if not is_instance_valid(asteroid) or asteroid.is_queued_for_deletion():
				return _fail("the asteroid broke after %d of its %d hit points" % [hit_points - 1, hit_points])
			print("asteroid survived %d of %d hit points" % [hit_points - 1, hit_points])

			asteroid.take_damage(1)
			if is_instance_valid(asteroid) and not asteroid.is_queued_for_deletion():
				return _fail("the asteroid survived its full %d hit points" % hit_points)
			stage = 1
			elapsed = 0.0
			return false
		1:
			# The drop is deferred - it is created from inside a signal, where
			# the physics server refuses a direct add_child.
			if elapsed < 0.2:
				return false
			var dropped: Array = get_nodes_in_group("rocks")
			if dropped.is_empty():
				return _fail("destroying an asteroid left no ore behind")
			print("destroyed asteroid dropped %d ore node(s)" % dropped.size())

			# --- C. the ore is fetchable ---------------------------------
			hold_before = game_state.fleet_resource(GameState.RESOURCE_ORE)
			var ship: Node2D = fleet.ships[0]
			# Placed just clear of the ship rather than on top of it, so the
			# rock's own drift has to bring it in - that pull is how a player
			# actually collects one.
			dropped[0].position = ship.global_position + Vector2(80.0, 0.0)
			stage = 2
			elapsed = 0.0
			return false
		2:
			if elapsed < 1.5:
				return false
			var gained: int = game_state.fleet_resource(GameState.RESOURCE_ORE) - hold_before
			if gained <= 0:
				return _fail("flying over the dropped ore put nothing in the hold")
			print("dropped ore collected into the fleet hold (+%d)" % gained)

			# --- D. ramming yields nothing -------------------------------
			_clear_sky()
			hold_before = game_state.fleet_resource(GameState.RESOURCE_ORE)
			asteroid = _spawn_asteroid(fleet.ships[0].global_position)
			stage = 3
			elapsed = 0.0
			return false
		3:
			if elapsed < 0.5:
				return false
			if is_instance_valid(asteroid) and not asteroid.is_queued_for_deletion():
				return _fail("an asteroid dropped onto a ship did not shatter against it")
			if not get_nodes_in_group("rocks").is_empty():
				return _fail("ramming an asteroid yielded ore - a shield vessel could farm them that way")
			if game_state.fleet_resource(GameState.RESOURCE_ORE) != hold_before:
				return _fail("ramming an asteroid changed the hold")
			print("ramming shattered the asteroid and yielded nothing")

			# --- E. abandoned ore expires, authored ore does not ----------
			_clear_sky()
			var abandoned: Node2D = load("res://surface/Rock.tscn").instantiate()
			abandoned.build_shape(1)
			abandoned.lifetime = 0.4
			# Far from every ship, or it would be collected rather than expire.
			abandoned.position = fleet.get_centroid() + Vector2(9000.0, 0.0)
			main.add_child(abandoned)
			var authored: Node2D = load("res://surface/Rock.tscn").instantiate()
			authored.build_shape(2)
			authored.position = fleet.get_centroid() + Vector2(9600.0, 0.0)
			main.add_child(authored)
			if authored.lifetime != 0.0:
				return _fail("a plain rock has a lifetime of %.1f - surface rocks must live forever" % authored.lifetime)
			stage = 4
			elapsed = 0.0
			return false
		4:
			if elapsed < 1.0:
				return false
			var survivors: Array = get_nodes_in_group("rocks")
			var names: Array = []
			for rock in survivors:
				names.append(rock.name)
			if survivors.size() != 1:
				return _fail("expected only the authored rock to remain, found %d: %s" % [survivors.size(), str(names)])
			print("abandoned ore expired; the rock with no lifetime is still there")

			print("TEST_ASTEROID_MINING: PASS")
			quit(0)
			return true
	return false


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