chess-moves.kt

@Composable
fun Moves(
    gameState: GameState,
    onClickMove: (Int) -> Unit,
) {
    val listState = rememberLazyListState()
    val coroutineScope = rememberCoroutineScope()

    LazyRow(
        state = listState,
        modifier = Modifier.padding(start = 16.dp, end = 16.dp),
        verticalAlignment = Alignment.CenterVertically
    ) {
        val moves = gameState.moves()
        val selectedItemIndex = gameState.currentIndex - 1
        moves.forEachIndexed { index, move ->
            val selected = index == selectedItemIndex

            // Move number vs ply (half-move) number
            if (index % 2 == 0) {
                item {
                    StepNumber(index / 2 + 1)
                    Spacer(modifier = Modifier.width(2.dp))
                }
            }

            // Passing a key to item
            item("$index$selected") {
                if (selected) {
                    Pill {
                        Move(move) { onClickMove(index) }
                    }
                } else {
                    Move(move) { onClickMove(index) }
                }
            }

            // Some trailing space after every second move
            if (index % 2 == 1) {
                item {
                    Spacer(modifier = Modifier.width(10.dp))
                }
            }
        }

        // Scroll to the currently selected one
        if (moves.isNotEmpty()) {
            coroutineScope.launch {
                listState.animateScrollToItem(selectedItemIndex * 2)
            }
        }
    }
}