# physics_push_test —— §3.7：受击击退物理（GameLib/PhysicsObject.cpp CPhysicsObject +
# MapUtil.cpp CEaseOutInterpolation）headless 自检。
#   godot --headless --path project --script physics_push_test.gd
extends SceneTree

const PhysicsPush = preload("res://physics_push.gd")

var _fail := 0
func _ck(c: bool, m: String) -> void:
	if not c:
		_fail += 1
		printerr("FAIL: " + m)

func _init() -> void:
	_run()
	if _fail == 0:
		print("PASS: physics_push_test (external force / friction / ease-out blend)")
		quit(0)
	else:
		printerr("%d check(s) failed" % _fail)
		quit(1)

func _run() -> void:
	# 初始：不在 blending，每帧位移 0
	var p := PhysicsPush.new()
	_ck(not p.is_blending(), "fresh object -> not blending")
	p.update(0.02)
	_ck(p.get_movement() == Vector2.ZERO, "fresh object -> zero movement")

	# IncreaseExternalForce(F=3, dir +X)：vel 3 -> 每步摩擦 0.3，累计 2.7+2.4+…+0.3 = 13.5 cm
	p.set_direction(Vector2(1, 0))
	p.increase_external_force(3.0)
	_ck(absf(p.get_last_position().x - 13.5) < 0.001 and absf(p.get_last_position().y) < 0.001,
			"F=3 along +X -> last position (13.5, 0), got %s" % p.get_last_position())
	_ck(p.is_blending(), "after push -> blending (ease-out playing)")

	# 逐帧 AddMovement(GetXMovement, GetYMovement)：2 秒 ease-out 累计 ≈ 13.5（离散 Euler 少 1/N）
	var sum := Vector2.ZERO
	var frames := 0
	while p.is_blending() and frames < 1000:
		p.update(0.02)
		sum += p.get_movement()
		frames += 1
	_ck(frames >= 99 and frames <= 101, "blend lasts LoopValue*c_fFrameTime = 2s, got %d frames" % frames)
	_ck(absf(sum.x - 13.5) < 0.3 and absf(sum.y) < 0.001, "ease-out total movement ≈ 13.5, got %s" % sum)
	p.update(0.02)
	_ck(p.get_movement() == Vector2.ZERO, "blend done -> movement 0")

	# 斜向：分量各自摩擦，13.5 * cos45
	var q := PhysicsPush.new()
	q.set_direction(Vector2(1, 1).normalized())
	q.increase_external_force(3.0)
	_ck(absf(q.get_last_position().x - 13.5 * 0.70710678) < 0.01 and absf(q.get_last_position().y - 13.5 * 0.70710678) < 0.01,
			"diagonal push -> per-axis 9.546, got %s" % q.get_last_position())

	# 分量 vel*dir < EPSILON(0.001) 当步清零（3*0.01*0.01 = 3e-4）
	var w := PhysicsPush.new()
	w.set_direction(Vector2(0.99995, 0.01))
	w.increase_external_force(3.0)
	_ck(w.get_last_position().y == 0.0, "tiny axis component zeroed on first step, got %s" % w.get_last_position())

	# 力为 0：没有位移，也不 blending（Setup(0,0,2) 仍在播放 -> isBlending 为真，与参考端一致）
	var z := PhysicsPush.new()
	z.set_direction(Vector2(1, 0))
	z.increase_external_force(0.0)
	_ck(z.get_last_position() == Vector2.ZERO, "zero force -> no movement")

	# 撞墙（IPhysicsWorld::isPhysicalCollision 为真）-> Initialize()，不推
	var c := PhysicsPush.new()
	c.set_direction(Vector2(1, 0))
	c.increase_external_force(3.0, func(_moved: Vector2) -> bool: return true)
	_ck(c.get_last_position() == Vector2.ZERO and not c.is_blending(), "world collision -> Initialize, no push")