/**
 * A part of a doll, such as a head, torso, arm or leg.
 * DollParts are created by a [Doll] (which also joins the parts together).
 * Note, a [Doll] is invisible, and only the [DollPart]s are visible.
 */
class DollPart : AbstractDraggable, Scalable {

    @CostumeAttribute(order = 1)
    val offset = Vector2()

    @CostumeAttribute(order = 2)
    val fromAngle = Angle.degrees(-180.0)

    @CostumeAttribute(order = 3)
    val toAngle = Angle.degrees(180.0)

    var doll: Doll = null

    override fun tick() {
        super.tick()
        // Does nothing. JBox2d takes care of all movements
    }

    override fun mass() = doll.totalMass

    override fun scale( by : Vector2 ) {
        doll.scale( by )
    }
}

/**
 * The only difference between MajorDollPart and [DollPart] is a test in tick().
 * If the velocity changes a lot, (i.e. the doll has collided with something) then a sound is made.
 * Only the head, torso and abdomen use this class, so no sound when an arm or leg collide.
 * Note, there is a large change in speed when a Doll is launched by a [Launcher]. However,
 * [Doll.hit] ignores this.
 */
class MajorDollPart : DollPart() {

    /**
     * Used to test for then the doll part has hit something
     */
    var oldSpeed = Vector2(0, 0)

    /**
     * Make a sound when the change in velocity is high (because it has hit something)
     */
    override fun tick() {
        val newSpeed = actor.body.linearVelocity

        val dx = Math.abs(oldSpeed.x - newSpeed.x)
        val dy = Math.abs(oldSpeed.y - newSpeed.y)
        if (dx > 100.0 || dy > 100.0) {
            doll.hit(dx + dy)
        }
        oldSpeed.set(newSpeed)
    }
}