Carousel

@OptIn(ExperimentalTvMaterial3Api::class, ExperimentalAnimationApi::class)

@Composable
fun SimpleCarousel() {
    @Composable
    fun Modifier.onFirstGainingVisibility(onGainingVisibility: () -> Unit): Modifier {
        var isVisible by remember { mutableStateOf(false) }
        LaunchedEffect(isVisible) { if (isVisible) onGainingVisibility() }

        return onPlaced { isVisible = true }
    }

    @Composable
    fun Modifier.requestFocusOnFirstGainingVisibility(): Modifier {
        val focusRequester = remember { FocusRequester() }
        return focusRequester(focusRequester).onFirstGainingVisibility {
            focusRequester.requestFocus()
        }
    }

    val backgrounds =
        listOf(
            Color.Red.copy(alpha = 0.3f),
            Color.Yellow.copy(alpha = 0.3f),
            Color.Green.copy(alpha = 0.3f),
        )

    var carouselFocused by remember { mutableStateOf(false) }
    Carousel(
        itemCount = backgrounds.size,
        modifier =
            Modifier.height(300.dp).fillMaxWidth().onFocusChanged {
                carouselFocused = it.isFocused
            },
        contentTransformEndToStart = fadeIn(tween(1000)).togetherWith(fadeOut(tween(1000))),
        contentTransformStartToEnd = fadeIn(tween(1000)).togetherWith(fadeOut(tween(1000))),
    ) { itemIndex ->
        Box(
            modifier =
                Modifier.background(backgrounds[itemIndex])
                    .border(2.dp, Color.White.copy(alpha = 0.5f))
                    .fillMaxSize()
        ) {
            var buttonFocused by remember { mutableStateOf(false) }
            val buttonModifier =
                if (carouselFocused) {
                    Modifier.requestFocusOnFirstGainingVisibility()
                } else {
                    Modifier
                }

            Button(
                onClick = {},
                modifier =
                    buttonModifier
                        .onFocusChanged { buttonFocused = it.isFocused }
                        .padding(40.dp)
                        .border(
                            width = 2.dp,
                            color = if (buttonFocused) Color.Red else Color.Transparent,
                            shape = RoundedCornerShape(50),
                        )
                        // Duration of animation here should be less than or equal to carousel's
                        // contentTransform duration to ensure the item below does not disappear
                        // abruptly.
                        .animateEnterExit(
                            enter = slideInHorizontally(animationSpec = tween(1000)) { it / 2 },
                            exit = slideOutHorizontally(animationSpec = tween(1000)),
                        )
                        .padding(vertical = 2.dp, horizontal = 5.dp),
            ) {
                Text(text = "Play")
            }
        }
    }
}