extends SceneTree

# Headless test: run with
#   godot --headless -s res://tests/test_shot_and_vfx_weight.gd
# Forgejo #155 ("default vessel shots should go faster and further") and #152
# ("add a vfx for dead enemies and for exploded rock and for resource
# collected on fleet").
#
# The #152 finding is worth recording: all three effects already existed and
# were already wired. What had happened is that #130 gave a lost VESSEL
# thirty particles and a shockwave, which left every other event in the game
# visibly smaller than it - a kill, the thing the player is rewarded for,
# was a twelve-particle puff beside it. So this is about PROPORTION, and
# proportion is what is checked: numbers get rebalanced, an ordering that
# says a rock outweighs a battleship is a bug.
#
# Covers:
#   A. the default gun outranges the enemies that stand off from it
#   B. a shot crosses that range quickly enough to read as hitting something
#   C. a shot's own lifetime is derived from its range, so faster does not
#      mean falling short
#   D. every one of #152's three events actually produces something
#   E. and they are in proportion - a lost vessel is the biggest, a rock is
#      not a puff, and nothing is on the base class's defaults

const ENEMY_STANDOFF = preload("res://enemies/EnemyStandoffComponent.gd")
const EXPLOSION_BASE = preload("res://vfx/ExplosionVFXBase.gd")

var game_state: Node
var scene: Node
var fleet: Node2D
var stage: int = 0
var elapsed: float = 0.0


func _initialize() -> void:
	# GameState is an autoload: a bare GameState.<instance member> does not
	# compile in a SceneTree script, so the node is fetched by name instead.
	game_state = root.get_node("GameState")
	game_state.reset_new_game()
	game_state.intro_active = false
	game_state.reset_quests()


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


func _count(of_class) -> int:
	var n: int = 0
	for node in root.get_children():
		if is_instance_of(node, of_class):
			n += 1
	return n


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			# --- A, B, C. the shot ----------------------------------
			var range_units: float = game_state.ship_fire_range(GameState.VESSEL_INTERCEPTOR)
			var shot: Node2D = load("res://vessels/Projectile.tscn").instantiate()
			var speed: float = shot.speed
			shot.set_range(range_units)
			var flight: float = shot.lifetime
			var standoff: float = ENEMY_STANDOFF.new().preferred_range

			if range_units <= standoff:
				return _fail("the default gun reaches %.0f and enemies stand off at %.0f - it is outranged" \
					% [range_units, standoff])
			if flight > 0.9:
				return _fail("a shot takes %.2fs to cross its own range - that reads as leaving, not hitting" \
					% flight)
			if absf(flight - range_units / speed) > 0.001:
				return _fail("lifetime %.3fs does not match range %.0f at speed %.0f - shots would fall short or overshoot" \
					% [flight, range_units, speed])
			print("default gun: %.0f units at %.0f/s, crossing its range in %.2fs (enemies stand off at %.0f)" \
				% [range_units, speed, flight, standoff])
			shot.free()

			scene = load("res://world/Main.tscn").instantiate()
			root.add_child(scene)
			current_scene = scene
			fleet = scene.get_node("Fleet")
			elapsed = 0.0
			stage = 1
			return false
		1:
			if elapsed < 0.4:
				return false
			scene.get_node("AsteroidField").set_process(false)
			scene.get_node("EnemySpawner").set_process(false)
			for hazard in get_nodes_in_group("asteroids") + get_nodes_in_group("enemies"):
				hazard.free()

			# --- D. an enemy dying is seen --------------------------
			var enemy: Node2D = load("res://enemies/Enemy.tscn").instantiate()
			enemy.enemy_id = "chaser"
			enemy.position = Vector2(600.0, 0.0)
			scene.add_child(enemy)
			var before: int = _count(EnemyExplosionVFX)
			enemy.take_damage(999)
			if _count(EnemyExplosionVFX) <= before:
				return _fail("an enemy died with nothing to show for it")

			# --- ...a rock breaking up ------------------------------
			var rock: Node2D = load("res://world/Asteroid.tscn").instantiate()
			rock.position = Vector2(-600.0, 0.0)
			scene.add_child(rock)
			var rocks_before: int = _count(AsteroidExplosionVFX)
			rock.shatter(false)
			if _count(AsteroidExplosionVFX) <= rocks_before:
				return _fail("a rock broke up with nothing to show for it")

			# --- ...and ore reaching the hold -----------------------
			var pickup_script: GDScript = load("res://vfx/ResourcePickupVFX.gd")
			var pickups_before: int = _count(pickup_script)
			pickup_script.spawn(root, Vector2.ZERO, GameState.RESOURCE_ORE, 1)
			if _count(pickup_script) <= pickups_before:
				return _fail("collecting ore showed nothing")
			print("all three events produce an effect")

			# --- E. and they are in proportion ----------------------
			var base: Node2D = EXPLOSION_BASE.new()
			var ship: Node2D = ShipExplosionVFX.new()
			var kill: Node2D = EnemyExplosionVFX.new()
			var stone: Node2D = AsteroidExplosionVFX.new()
			for pair in [["a lost vessel", ship], ["an enemy kill", kill], ["a broken rock", stone]]:
				var vfx: Node2D = pair[1]
				if vfx.particle_count <= base.particle_count:
					return _fail("%s is still on the base class's %d particles" \
						% [pair[0], base.particle_count])
				if vfx.shockwave_radius <= 0.0:
					return _fail("%s has no shockwave behind it" % pair[0])
			if ship.particle_count < kill.particle_count:
				return _fail("losing a vessel (%d) is smaller than killing an enemy (%d)" \
					% [ship.particle_count, kill.particle_count])
			if kill.particle_count < stone.particle_count:
				return _fail("killing an enemy (%d) is smaller than breaking a rock (%d)" \
					% [kill.particle_count, stone.particle_count])
			print("particles: vessel %d > enemy %d > rock %d > base default %d" \
				% [ship.particle_count, kill.particle_count, stone.particle_count,
					base.particle_count])
			for vfx in [base, ship, kill, stone]:
				vfx.free()

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