extends Node3D
## Headless physics probe. Run via run_probe.sh, which switches the physics
## engine through override.cfg and launches this scene under each backend.
##
## Test 1 — tunneling: fire a ball at a 1 cm static wall at increasing speeds,
## with CCD off and on, and report whether the wall contains it.
## Test 2 — hinge motor: drive a hinged arm with a joint motor and report
## whether it actually rotates (a flipper is a motorised hinge).

const WALL_THICKNESS := 0.01
const BALL_RADIUS := 0.0135
const START_Z := 2.0
const SPEEDS := [5.0, 10.0, 20.0, 40.0, 80.0, 160.0]

func _ready() -> void:
	var engine := str(ProjectSettings.get_setting("physics/3d/physics_engine"))
	print("PROBE_START engine=%s tick=%d" % [engine, Engine.physics_ticks_per_second])
	_run(engine)

func _run(engine: String) -> void:
	var wall := StaticBody3D.new()
	var cs := CollisionShape3D.new()
	var box := BoxShape3D.new()
	box.size = Vector3(1.0, 1.0, WALL_THICKNESS)
	cs.shape = box
	wall.add_child(cs)
	add_child(wall)

	for ccd in [false, true]:
		for speed in SPEEDS:
			var r := await _fire(float(speed), ccd)
			print("PROBE engine=\"%s\" speed=%d ccd=%s result=%s final_z=%.3f drift_y=%.4f" % [
				engine, int(speed), "on" if ccd else "off",
				"tunneled" if r.tunneled else "contained", r.final_z, r.drift_y])

	var m := await _motor_test()
	print("PROBE_MOTOR engine=\"%s\" moved_deg=%.1f works=%s" % [
		engine, m.moved_deg, "yes" if m.moved_deg > 20.0 else "NO"])

	get_tree().quit(0)

func _fire(speed: float, ccd: bool) -> Dictionary:
	var ball := RigidBody3D.new()
	var cs := CollisionShape3D.new()
	var sph := SphereShape3D.new()
	sph.radius = BALL_RADIUS
	cs.shape = sph
	ball.add_child(cs)
	ball.mass = 0.08
	ball.continuous_cd = ccd
	ball.gravity_scale = 0.0
	ball.can_sleep = false
	ball.position = Vector3(0, 0, START_Z)
	add_child(ball)
	ball.linear_velocity = Vector3(0, 0, -speed)

	# Enough ticks to cover the distance plus settle time.
	var ticks := maxi(90, int(ceil((START_Z + 1.0) / speed * 60.0)) + 30)
	for i in ticks:
		await get_tree().physics_frame

	var result := {
		"tunneled": ball.position.z < -(WALL_THICKNESS / 2.0 + BALL_RADIUS + 0.05),
		"final_z": ball.position.z,
		"drift_y": absf(ball.position.y),  # nonzero = gravity_scale unsupported
	}
	ball.queue_free()
	await get_tree().physics_frame
	return result

func _motor_test() -> Dictionary:
	var anchor := StaticBody3D.new()
	var acs := CollisionShape3D.new()
	var abox := BoxShape3D.new()
	abox.size = Vector3(0.05, 0.05, 0.05)
	acs.shape = abox
	anchor.add_child(acs)
	anchor.position = Vector3(3, 0, 0)  # far from the wall test
	add_child(anchor)

	var arm := RigidBody3D.new()
	var ccs := CollisionShape3D.new()
	var bbox := BoxShape3D.new()
	bbox.size = Vector3(0.1, 0.03, 0.022)
	ccs.shape = bbox
	ccs.position = Vector3(0.05, 0, 0)
	arm.add_child(ccs)
	arm.mass = 0.15
	arm.gravity_scale = 0.0
	arm.can_sleep = false
	arm.position = Vector3(3.1, 0, 0)
	add_child(arm)

	var joint := HingeJoint3D.new()
	# Local Z (the hinge axis) pointed along world +Y.
	joint.transform = Transform3D(Basis(Vector3(1, 0, 0), -PI / 2.0), Vector3(3.1, 0, 0))
	joint.set_flag(HingeJoint3D.FLAG_ENABLE_MOTOR, true)
	joint.set_param(HingeJoint3D.PARAM_MOTOR_TARGET_VELOCITY, 5.0)
	joint.set_param(HingeJoint3D.PARAM_MOTOR_MAX_IMPULSE, 5.0)
	add_child(joint)
	# Paths only resolve once the joint is inside the tree.
	joint.node_a = joint.get_path_to(anchor)
	joint.node_b = joint.get_path_to(arm)

	var start_q := arm.global_transform.basis.get_rotation_quaternion()
	for i in 60:
		await get_tree().physics_frame
	var end_q := arm.global_transform.basis.get_rotation_quaternion()
	var moved := start_q.angle_to(end_q)
	print("PROBE_MOTOR_DEBUG rotation=%s ang_vel=%s pos=%s" % [
		arm.rotation, arm.angular_velocity, arm.position])
	return {"moved_deg": rad_to_deg(moved)}