Lottie animation Jetpack Compose

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            ComposeLottieTheme {
                val composition by rememberLottieComposition(
                    spec = LottieCompositionSpec.Asset("anim.json")
                )
                var isPlaying by remember {
                    mutableStateOf(false)
                }
                var isComplete by remember {
                    mutableStateOf(false)
                }
                val animSpec = LottieClipSpec.Progress(
                    0f,
                    if(isComplete) 1f else 0.5f
                )


                Column(
                    modifier = Modifier.fillMaxSize(),
                    horizontalAlignment = Alignment.CenterHorizontally
                ) {
                    LottieAnimation(
                        composition = composition,
                        isPlaying = isPlaying,
                        speed = 1f,
                        iterations = if(isComplete) 1 else LottieConstants.IterateForever,
                        reverseOnRepeat = true,
                        clipSpec = animSpec
                    )
                    Button(
                        onClick = {
                            isPlaying = true
                        }) {
                        Text(text = "Download")
                    }
                    Button(
                        onClick = {
                            isComplete = true
                        }) {
                        Text(text = "Finish")
                    }
                    Button(
                        onClick = {
                            isComplete = false
                        }) {
                        Text(text = "Restart")
                    }
                }
            }
        }
    }
}