extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_enemy_mothership.gd
# Forgejo #53: a big, slow capital enemy that spawns chasers/artillery on
# their own intervals and fires a heavily telegraphed line beam.
#
# Split into two independent parts, each with its own fleet setup:
#   A. EnemyBigLaserBeam mechanics, tested directly (not through the
#      component's own tick/cooldown timing, which would make the precise
#      geometry assertions below timing-fragile):
#      1. the telegraph holds for the charge - no damage, phase stays
#         CHARGING, for most of charge_time
#      2. the locked aim direction never changes even if the fleet moves
#         away mid-charge
#      3. three ships in a line all die from one shot; a ship that steps
#         outside beam_half_width before the shot lands survives
#      4. a shielded ship in the beam survives, losing exactly one charge
#   B. The composed enemy_mothership definition, tested through a real
#      Enemy.tscn instance:
#      5. structural composition - pursuit, two DISTINCT spawner presets
#         (chaser/artillery), big_laser, no type switch anywhere
#      6. it launches both chaser and artillery spawns on their own
#         intervals
#      7. it closes on the fleet without ever exceeding its own defined
#         speed - "never reaches ramming speed"
#
# Repo-wide lessons from #52, both apply again here:
#   - main.get_node(...).set_process(false) has to happen in _process()'s
#     first real tick, not _initialize() - a disable made before the node
#     has finished entering the tree doesn't reliably stick.
#   - overriding an @export interval on an already-ticking component does
#     NOT reset its in-progress countdown - reset the timer variable too.

var game_state: Node
var main: Node
var fleet: Node
var beam_script: Script
var beam: Node2D
var line_a: Node
var line_b: Node
var line_c: Node
var shield_ship: Node
var initial_aim: Vector2
var mothership: Node
var chaser_spawner: Node
var artillery_spawner: Node
var mothership_start_position: Vector2
var closing_elapsed: float = 0.0
var stage: int = 0
var elapsed: float = 0.0


func _initialize() -> void:
	game_state = root.get_node("GameState")
	beam_script = load("res://enemies/EnemyBigLaserBeam.gd")
	# Four vessels are crewed below, past BASE_FLEET_SIZE's 3 slots, so the
	# capacity doctrines are granted rather than assumed.
	# #219: berths come from Fleet Offices now, not from research. Three of
	# them buy the same four-vessel fleet the doctrines used to. Left
	# unstocked deliberately - upkeep is not charged for the first
	# 25 seconds, and nothing here runs that long.
	for _berth in range(3):
		game_state.add_building(GameState.BUILDING_FLEET_OFFICE,
			Vector2(3000.0 + 400.0 * float(_berth), 3000.0))
	main = load("res://world/Main.tscn").instantiate()
	root.add_child(main)
	fleet = main.get_node("Fleet")


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if elapsed < 0.1:
				return false
			main.get_node("EnemySpawner").set_process(false)
			main.get_node("AsteroidField").set_process(false)
			main.get_node("BuildController").set_process(false)
			for ship in fleet.ships:
				if is_instance_valid(ship):
					ship.queue_free()
			fleet.ships.clear()

			# --- A: line-up three ships along +X, one shielded further out ---
			fleet.add_ship(game_state.VESSEL_INTERCEPTOR)
			line_a = fleet.ships[fleet.ships.size() - 1]
			_pin(line_a, Vector2(300, 0))
			fleet.add_ship(game_state.VESSEL_INTERCEPTOR)
			line_b = fleet.ships[fleet.ships.size() - 1]
			_pin(line_b, Vector2(400, 0))
			fleet.add_ship(game_state.VESSEL_INTERCEPTOR)
			line_c = fleet.ships[fleet.ships.size() - 1]
			_pin(line_c, Vector2(500, 0))
			fleet.add_ship(game_state.VESSEL_SHIELD)
			shield_ship = fleet.ships[fleet.ships.size() - 1]
			_pin(shield_ship, Vector2(600, 0))
			if not shield_ship.has_shield():
				return _fail("shield ship has no shield right after being added")

			var beam_scene: PackedScene = load("res://enemies/EnemyBigLaserBeam.tscn")
			beam = beam_scene.instantiate()
			beam.charge_time = 0.5
			beam.beam_range = 1000.0
			beam.beam_half_width = 35.0
			beam.damage = 3
			root.add_child(beam)
			beam.launch(Vector2.ZERO, Vector2(1, 0))
			initial_aim = beam.aim_direction
			elapsed = 0.0
			stage = 1
			return false
		1:
			# --- 1. telegraph holds, no damage, for most of the charge ---
			if elapsed < beam.charge_time * 0.6:
				return false
			if beam.phase != beam_script.Phase.CHARGING:
				return _fail("beam left CHARGING before charge_time elapsed")
			for ship in [line_a, line_b, line_c, shield_ship]:
				if not is_instance_valid(ship):
					return _fail("a ship in the beam's path died before the charge finished")

			# Move line_b out of the beam's path - this alone also shifts
			# fleet.get_centroid() (line_b is part of the same fleet), which
			# is exactly the "the fleet moved mid-charge" event stage 2
			# needs to prove the beam does NOT re-track. line_a/line_c/
			# shield_ship stay exactly where they were.
			_pin(line_b, Vector2(400, 400))
			elapsed = 0.0
			stage = 2
			return false
		2:
			if elapsed < beam.charge_time * 0.6:
				return false
			if beam.aim_direction != initial_aim:
				return _fail("beam re-tracked the fleet mid-charge - aim_direction changed from %s to %s" % [
					initial_aim, beam.aim_direction
				])
			elapsed = 0.0
			stage = 3
			return false
		3:
			# --- 3 + 4. the shot has landed by now ---
			if is_instance_valid(line_a):
				return _fail("line_a (still in the beam) survived the shot")
			if is_instance_valid(line_c):
				return _fail("line_c (still in the beam) survived the shot")
			if not is_instance_valid(line_b):
				return _fail("line_b (moved out of the beam before it fired) was killed anyway")
			if not is_instance_valid(shield_ship):
				return _fail("the shielded ship died despite having a shield")
			if shield_ship.shield_charges != 0:
				return _fail("shield charges did not drop to exactly 1 lost (charges=%d)" % shield_ship.shield_charges)

			# --- B: reset to a clean single-ship fleet for the mothership ---
			for ship in fleet.ships:
				if is_instance_valid(ship):
					ship.queue_free()
			fleet.ships.clear()
			fleet.spawn_ships(1, Vector2(3000, 0))

			mothership = load("res://enemies/Enemy.tscn").instantiate()
			mothership.enemy_id = "enemy_mothership"
			mothership.position = Vector2.ZERO
			main.add_child(mothership)
			elapsed = 0.0
			stage = 4
			return false
		4:
			if elapsed < 0.15:
				return false
			# --- 5. structural composition, no type switch ---
			if mothership.max_hp != 60:
				return _fail("enemy_mothership max_hp is %d, expected 60" % mothership.max_hp)
			# Compared against the CHASER rather than a hardcoded 35.0. What
			# matters is that this thing lumbers - "never reaches ramming
			# speed", per the note at the top of this file - and that is a
			# statement about the two relative to each other. The literal was
			# a hidden dependency on one balance pass: #88 raised every speed
			# in the game by 1.5 and this failed while the mothership was
			# still exactly as slow, relatively, as it had always been.
			var definitions: Script = load("res://enemies/EnemyDefinitions.gd")
			var chaser_speed: float = float(definitions.get_definition("chaser").speed)
			if mothership.speed >= chaser_speed * 0.5:
				return _fail("enemy_mothership moves at %s against a chaser's %s - it is meant to lumber" \
					% [mothership.speed, chaser_speed])
			if not mothership.has_capability("pursuit"):
				return _fail("enemy_mothership has no pursuit component - it should close on the fleet")
			if not mothership.has_capability("big_laser"):
				return _fail("enemy_mothership has no big_laser component")

			var spawners: Array = []
			for child in mothership.get_children():
				if child.get("capability_id") == "spawner":
					spawners.append(child)
			if spawners.size() != 2:
				return _fail("enemy_mothership has %d spawner components, expected 2 (chaser + artillery)" % spawners.size())
			for spawner in spawners:
				if spawner.spawned_enemy_id == "chaser":
					chaser_spawner = spawner
				elif spawner.spawned_enemy_id == "artillery":
					artillery_spawner = spawner
			if chaser_spawner == null or artillery_spawner == null:
				return _fail("the two spawner components are not one chaser + one artillery preset")

			# Speed up both intervals for the test, resetting the in-progress
			# timer too (#52's lesson: changing the interval alone does not
			# touch a countdown already running from the definition default).
			# Staggered slightly rather than both at 0.0: two sibling
			# spawners both instantiating Enemy.tscn on the exact same
			# physics frame hit a transient PackedScene.instantiate()
			# failure ("node count is 0") on this engine build - spreading
			# their first fire across different frames avoids it, and is
			# also what naturally happens in real play anyway.
			chaser_spawner.spawn_interval = 0.2
			chaser_spawner.spawn_timer = 0.0
			artillery_spawner.spawn_interval = 0.3
			artillery_spawner.spawn_timer = 0.05

			mothership_start_position = mothership.position
			elapsed = 0.0
			closing_elapsed = 0.0
			stage = 5
			return false
		5:
			# --- 6. launches both chasers and artillery on their own intervals ---
			closing_elapsed += delta
			if elapsed < 1.2:
				return false
			if chaser_spawner.spawned.is_empty():
				return _fail("mothership never spawned a chaser")
			if artillery_spawner.spawned.is_empty():
				return _fail("mothership never spawned an artillery")
			for spawn in chaser_spawner.spawned:
				if spawn.enemy_id != "chaser":
					return _fail("a chaser-spawner spawn has enemy_id '%s'" % spawn.enemy_id)
			for spawn in artillery_spawner.spawned:
				if spawn.enemy_id != "artillery":
					return _fail("an artillery-spawner spawn has enemy_id '%s'" % spawn.enemy_id)

			# --- 7. closes on the fleet, never exceeding its own speed ---
			var traveled: float = mothership.position.distance_to(mothership_start_position)
			var max_possible: float = mothership.speed * closing_elapsed + 5.0   # small integration slack
			if traveled > max_possible:
				return _fail("mothership traveled %.1f in %.2fs, more than speed(%.1f) allows (%.1f)" % [
					traveled, closing_elapsed, mothership.speed, max_possible
				])
			var distance_to_fleet: float = mothership.position.distance_to(fleet.get_centroid())
			var starting_distance: float = mothership_start_position.distance_to(Vector2(3000, 0))
			if distance_to_fleet >= starting_distance:
				return _fail("mothership did not close on the fleet at all (distance %.1f >= starting %.1f)" % [
					distance_to_fleet, starting_distance
				])

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


func _pin(ship: Node, at: Vector2) -> void:
	ship.position = at
	ship.move_target = at


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