extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_asteroid_spawning.gd
# Verifies AsteroidField spawns moving asteroids once the fleet enters an
# ASTEROID_FIELD biome chunk, and despawns them again once the fleet moves
# far enough away - guards against unbounded node accumulation over a long
# play session while still populating newly-entered regions on the fly.

var main_scene: Node
var fleet: Node
var asteroid_field: Node
var asteroid_chunk: Vector2i
var spawned_asteroids: Array = []
var elapsed: float = 0.0
var stage: int = 0
var ok: bool = true


func _initialize() -> void:
	var found: bool = false
	for x in range(-15, 15):
		for y in range(-15, 15):
			var chunk: Vector2i = Vector2i(x, y)
			if WorldGen.biome_at_chunk(chunk) == WorldGen.Biome.ASTEROID_FIELD:
				asteroid_chunk = chunk
				found = true
				break
		if found:
			break

	if not found:
		print("FAIL: could not find any ASTEROID_FIELD chunk to test with")
		quit(1)
		return

	var packed: PackedScene = load("res://world/Main.tscn")
	main_scene = packed.instantiate()
	root.add_child(main_scene)
	fleet = main_scene.get_node("Fleet")
	asteroid_field = main_scene.get_node("AsteroidField")


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			# Wait one tick so Fleet._ready() has run and fleet.ships is
			# populated before we try to teleport them - reposition
			# attempted synchronously in _initialize() would silently
			# no-op on an empty ships array.
			var target_pos: Vector2 = WorldGen.chunk_origin(asteroid_chunk) + Vector2.ONE * WorldGen.CHUNK_SIZE * 0.5
			for ship in fleet.ships:
				ship.position = target_pos
			fleet.move_to(target_pos)
			elapsed = 0.0
			stage = 1
			return false
		1:
			if elapsed < asteroid_field.check_interval + 0.1:
				return false
			_check_spawned()
			elapsed = 0.0
			stage = 2
			return false
		2:
			var far_pos: Vector2 = WorldGen.chunk_origin(asteroid_chunk) + Vector2(50000, 50000)
			for ship in fleet.ships:
				ship.position = far_pos
			fleet.move_to(far_pos)
			elapsed = 0.0
			stage = 3
			return false
		3:
			if elapsed < asteroid_field.check_interval + 0.1:
				return false
			_check_despawned()
			return true
	return false


func _check_spawned() -> void:
	var has_chunk: bool = asteroid_field.populated_chunks.has(asteroid_chunk)
	if not has_chunk:
		ok = false
		print("FAIL: asteroid_chunk %s not populated after check_interval" % asteroid_chunk)
		return

	spawned_asteroids = asteroid_field.populated_chunks[asteroid_chunk]
	var count_ok: bool = spawned_asteroids.size() == asteroid_field.asteroids_per_chunk
	var moving_ok: bool = true
	for asteroid in spawned_asteroids:
		if asteroid.velocity.length() <= 0.1:
			moving_ok = false

	ok = ok and count_ok and moving_ok
	print("spawned_count=%d expected=%d moving_ok=%s" % [spawned_asteroids.size(), asteroid_field.asteroids_per_chunk, moving_ok])


func _check_despawned() -> void:
	var chunk_removed: bool = not asteroid_field.populated_chunks.has(asteroid_chunk)
	var all_freed: bool = true
	for asteroid in spawned_asteroids:
		if is_instance_valid(asteroid):
			all_freed = false

	ok = ok and chunk_removed and all_freed
	print("chunk_removed=%s all_freed=%s" % [chunk_removed, all_freed])

	if ok:
		print("TEST_ASTEROID_SPAWNING: PASS")
		quit(0)
	else:
		print("TEST_ASTEROID_SPAWNING: FAIL")
		quit(1)