extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_enemy_combat.gd
# Verifies the fleet auto-fires on an enemy within range and kills it after
# a few hits, without the enemy ever having to touch a ship, and that a
# coherent red light-burst explosion VFX spawns at the moment it dies.

const TEST_DURATION: float = 3.0
const SPAWN_OFFSET: Vector2 = Vector2(220, 0)  # inside fire_range, outside collision radius

var main_scene: Node
var fleet: Node
var enemy: 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)
		var enemy_scene: PackedScene = load("res://Enemy.tscn")
		enemy = enemy_scene.instantiate()
		enemy.position = fleet.get_centroid() + SPAWN_OFFSET
		main_scene.add_child(enemy)
		started = true
		return false

	elapsed += delta

	if not is_instance_valid(enemy):
		_finish(true, "enemy destroyed by fleet fire after %.2fs" % elapsed)
		return true

	if elapsed >= TEST_DURATION:
		_finish(false, "enemy still alive after %.2fs (hp=%d)" % [elapsed, enemy.hp])
		return true

	return false


func _finish(ok: bool, message: String) -> void:
	print("ships_remaining=%d" % fleet.ships.size())
	print(message)

	var vfx_ok: bool = false
	for child in root.get_children():
		if child is EnemyExplosionVFX:
			vfx_ok = true
	print("enemy_vfx_ok=%s" % vfx_ok)

	if ok and fleet.ships.size() == 5 and vfx_ok:
		print("TEST_ENEMY_COMBAT: PASS")
		quit(0)
	else:
		if fleet.ships.size() != 5:
			print("FAIL: a ship was lost - enemy must have reached melee range instead of dying to fire")
		if not vfx_ok:
			print("FAIL: no matching red light-burst explosion VFX found for the destroyed enemy")
		print("TEST_ENEMY_COMBAT: FAIL")
		quit(1)