class AnimationHandler(private val animationFactory: AnimatorFactory, private val animationListProvider: vg2.a<List<wg2.a>, Payload>) {

    private val animationList = mutableListOf<Animation>()
    private val animationObserver = vg2.c<List<wg2.a>, Unit>(emptyList())
    private val animator = AnimatorFactory.createAnimator(animationFactory, 0.5f, 0.0f, AccelerateDecelerateInterpolator(), 2, null)

    init {
        animationListProvider.registerObserver(AnimationObserver(this))
    }

    private fun updateAnimationList() {
        val animations = if (animator.isRunning) animationList else animationListProvider.get()
        vg2.c.update(animationObserver, animations, null, 2, null)
    }

    private fun createAnimation(animation: wg2.a, animate: Boolean): wg2.a {
        val animationList = if (animate) listOf(tg2.createAnimation(animation.x(), animation.c())) else emptyList()
        return yg2.b(tg2.h(animationList))
    }

    fun getAnimationObserver(): vg2.a<List<wg2.a>, Unit> {
        return animationObserver
    }

    fun isAnimatorRunning(): Boolean {
        return animator.isRunning
    }

    fun updateAnimations(animations: List<wg2.a>, payload: Payload?) {
        val animate = payload?.isAnimate() ?: false
        if (!animate) {
            qg2.a.stopAnimator(animator, false, 1, null)
            updateAnimationList()
            return
        }
        animationList.clear()
        animations.forEach { animation ->
            animationList.add(createAnimation(animation, true))
        }
        while (animations.size < animationList.size) {
            animations.add(createAnimation(animations.last(), true))
        }
        animationList.clear()
        for (i in animations.indices) {
            animationList.add(Animation(animationList[i], animations[i]))
        }
        animator.animate(0.0f, 1.0f, animate)
    }

    fun updateAnimationProgress() {
        if (animator.isRunning) {
            val progress = animator.progress
            for (i in animationList.indices) {
                animationList[i].updateProgress(progress)
            }
            updateAnimationList()
        }
    }

    class Payload(private val animate: Boolean) {

        fun isAnimate(): Boolean {
            return animate
        }

        override fun equals(other: Any?): Boolean {
            if (this === other) return true
            if (other !is Payload) return false
            return animate == other.animate
        }

        override fun hashCode(): Int {
            return animate.hashCode()
        }

        override fun toString(): String {
            return "Payload(animate=$animate)"
        }
    }

    class Animation(private val animation1: wg2.a, private val animation2: wg2.a) {
        // The rest of the class implementation goes here
    }

    class AnimationObserver(private val handler: AnimationHandler) : Observer {
        // The rest of the class implementation goes here
    }
}