MutatorMutex

import androidx.compose.foundation.MutatorMutex
import androidx.compose.foundation.layout.Row
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.Stable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.rememberCoroutineScope

@Stable
class ScrollState(position: Int = 0) {
    private var _position by mutableStateOf(position)
    var position: Int
        get() = _position.coerceAtMost(range)
        set(value) {
            _position = value.coerceIn(0, range)
        }

    private var _range by mutableStateOf(0)
    var range: Int
        get() = _range
        set(value) {
            _range = value.coerceAtLeast(0)
        }

    var isScrolling by mutableStateOf(false)
        private set

    private val mutatorMutex = MutatorMutex()

    /** Only one caller to [scroll] can be in progress at a time. */
    suspend fun <R> scroll(block: suspend () -> R): R =
        mutatorMutex.mutate {
            isScrolling = true
            try {
                block()
            } finally {
                // MutatorMutex.mutate ensures mutual exclusion between blocks.
                // By setting back to false in the finally block inside mutate, we ensure that
                // we
                // reset the state upon cancellation before the next block starts to run (if
                // any).
                isScrolling = false
            }
        }
}

/** Arbitrary animations can be defined as extensions using only public API */
suspend fun ScrollState.animateTo(target: Int) {
    scroll { animate(from = position, to = target) { newPosition -> position = newPosition } }
}

/**
 * Presents two buttons for animating a scroll to the beginning or end of content. Pressing one
 * will cancel any current animation in progress.
 */
@Composable
fun ScrollControls(scrollState: ScrollState) {
    Row {
        val scope = rememberCoroutineScope()
        Button(onClick = { scope.launch { scrollState.animateTo(0) } }) {
            Text("Scroll to beginning")
        }
        Button(onClick = { scope.launch { scrollState.animateTo(scrollState.range) } }) {
            Text("Scroll to end")
        }
    }
}