extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_building_collateral.gd
# Forgejo #176: the player's own ships and their weapons do not damage the
# player's buildings. Friendly fire on structures made defending them with a
# gas bomb or crossing them at speed punish ordinary play.
#
# Covers:
#   A. a bomb landing on a structure leaves it unharmed
#   B. a bomb landing clear of it does not - the radius is the radius, and
#      this is a weapon that has to be aimed
#   C. a vessel resting against a structure does NOT damage it. The fleet
#      sits on its own mothership constantly to bank ore; if that hurt, the
#      game's own economy loop would grind its buildings down
#   D. a vessel arriving fast still does not damage it or itself

var game_state: Node
var main: Node
var fleet: Node
var building_id: int = 0
var stage: int = 0
var elapsed: float = 0.0
var hp_before: int = 0
var ships_before: int = 0
const BUILDING_AT := Vector2(1200.0, 0.0)


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 _hp() -> int:
	return int(game_state.find_building(building_id).get("hp", 0))


func _detonate_at(at: Vector2) -> void:
	var bomb: Node2D = load("res://vfx/GasBombEffect.gd").new()
	main.add_child(bomb)
	bomb.target = at
	bomb.damage = 6
	bomb._explode()
	bomb.queue_free()


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if elapsed < 0.4:
				return false
			main.get_node("EnemySpawner").set_process(false)
			main.get_node("AsteroidField").set_process(false)
			for hazard in get_nodes_in_group("asteroids") + get_nodes_in_group("enemies"):
				if is_instance_valid(hazard):
					hazard.queue_free()
			main.get_node("BuildingField").place(GameState.BUILDING_MOTHERSHIP, BUILDING_AT)
			building_id = int(game_state.buildings[0].id)
			if _hp() <= 0:
				return _fail("the structure has no hit points to lose")
			stage = 1
			elapsed = 0.0
			return false
		1:
			if elapsed < 0.2:
				return false
			# --- B. a bomb well clear of it does nothing ------------------
			hp_before = _hp()
			_detonate_at(BUILDING_AT + Vector2(900.0, 0.0))
			if _hp() != hp_before:
				return _fail("a bomb 900 away still damaged the structure")
			print("a bomb clear of the structure leaves it alone")

			# --- A. a friendly bomb on top of it is safe ----------------------
			_detonate_at(BUILDING_AT)
			if _hp() != hp_before:
				return _fail("a friendly bomb damaged the structure (%d -> %d)" % [hp_before, _hp()])
			print("a friendly bomb on the structure leaves it at %d hp" % _hp())

			# --- C. resting against it is free ------------------------------
			hp_before = _hp()
			fleet.spawn_ships(1, BUILDING_AT, PackedStringArray([GameState.VESSEL_INTERCEPTOR]))
			for ship in fleet.ships:
				ship.global_position = BUILDING_AT
				ship.velocity = Vector2.ZERO
			stage = 2
			elapsed = 0.0
			return false
		2:
			# Long enough for several strike ticks to have passed.
			if elapsed < 2.0:
				return false
			for ship in fleet.ships:
				ship.velocity = Vector2.ZERO
			if _hp() != hp_before:
				return _fail("a vessel resting on the structure damaged it (%d -> %d) - the fleet docks here to bank ore" \
					% [hp_before, _hp()])
			print("a vessel parked on the structure for %.1fs did nothing to it" % elapsed)

			# --- D. arriving fast is still friendly -------------------------
			hp_before = _hp()
			ships_before = fleet.ships.size()
			for ship in fleet.ships:
				# Placed clear and sent IN, because the impact is detected on
				# entry - a ship spawned already overlapping never enters.
				ship.global_position = BUILDING_AT - Vector2(400.0, 0.0)
				ship.velocity = Vector2(900.0, 0.0)
				ship.set_move_target(BUILDING_AT + Vector2(600.0, 0.0))
			stage = 3
			elapsed = 0.0
			return false
		3:
			if elapsed < 1.2:
				return false
			if _hp() != hp_before:
				return _fail("a fast friendly vessel damaged the structure (%d -> %d)" % [hp_before, _hp()])
			if fleet.ships.size() != ships_before:
				return _fail("a friendly building destroyed a vessel crossing it")
			print("a vessel crossing the structure at speed leaves both unharmed")

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


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