advent of code 2022 day 5 cparsing

parsing.kt

fun parseFilePart1(inputStream: InputStream) = with(inputStream.bufferedReader()) {
        var line: String? = null
        val stacksRaw = mutableListOf<String>()
        val moves = mutableListOf<List<Int>>()
        var movesListBegun = false
        while (true) {
            line = readLine()

            when {
                line == null -> break
                line.isBlank() -> movesListBegun = true
                !movesListBegun -> stacksRaw.add(line)
                else -> {
                    val values = MOVE_REGEX.find(line)!!.destructured.toList().map(String::toInt)
                    moves.add(values)
                }
            }
        }
        val numberStacks = stacksRaw.last().trim().split("""\s+""".toRegex()).last().toInt()

        val stacks = (1..numberStacks).map { ArrayDeque<String>() }

        stacksRaw.dropLast(1).reversed().forEach { line ->
            (1..numberStacks).forEach { id ->
                val crate = try {
                    (1 + 4 * (id - 1)).let { line.substring(it..it) }
                } catch (e: StringIndexOutOfBoundsException) {
                    ""
                }
                if(crate.isNotBlank()) stacks[id - 1].add(crate)
            }
        }

        stacks to moves
    }