extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_enemy_collision.gd
# Verifies that an enemy touching a ship destroys that ship, is removed
# from the fleet, while the enemy itself survives the touch (enemies only
# die from being shot, not from ramming).

const CHECK_DELAY: float = 0.05

var main_scene: Node
var fleet: Node
var enemy: Node
var target_ship: Node
var elapsed: float = 0.0
var started: bool = false


func _initialize() -> void:
	var packed: PackedScene = load("res://Main.tscn")
	main_scene = packed.instantiate()
	root.add_child(main_scene)
	fleet = main_scene.get_node("Fleet")


func _physics_process(delta: float) -> bool:
	if not started:
		# Disabling EnemySpawner in _initialize() doesn't reliably stick -
		# a node's set_process(false) call made before it has fully
		# finished entering the tree can get silently reset once the
		# engine's own (deferred) tree-entry finalization runs, which
		# happens strictly after _ready(). Here, at the point _ready() is
		# already confirmed complete, it's safe.
		main_scene.get_node("EnemySpawner").set_process(false)
		target_ship = fleet.ships[0]
		var enemy_scene: PackedScene = load("res://Enemy.tscn")
		enemy = enemy_scene.instantiate()
		enemy.position = target_ship.position
		main_scene.add_child(enemy)
		started = true
		return false

	elapsed += delta
	if elapsed >= CHECK_DELAY:
		_finish()
		return true
	return false


func _finish() -> void:
	var ship_destroyed: bool = not is_instance_valid(target_ship)
	var ship_removed_from_fleet: bool = fleet.ships.find(target_ship) == -1
	var fleet_count_ok: bool = fleet.ships.size() == 4
	var enemy_survived: bool = is_instance_valid(enemy) and enemy.hp > 0

	print("ship_destroyed=%s ship_removed_from_fleet=%s ships_remaining=%d enemy_survived=%s" % [
		ship_destroyed, ship_removed_from_fleet, fleet.ships.size(), enemy_survived
	])

	if ship_destroyed and ship_removed_from_fleet and fleet_count_ok and enemy_survived:
		print("TEST_ENEMY_COLLISION: PASS")
		quit(0)
	else:
		print("TEST_ENEMY_COLLISION: FAIL")
		quit(1)