class Day06 : Puzzle {

    val numsPartOne = mutableListOf<MutableList<Long>>()
    val numsPartTwo = mutableListOf<List<Long>>()
    val ops = mutableListOf<(Long, Long) -> Long>()

    override fun readFile() {
        val input = readInputFromFile("src/main/resources/a2025/day06.txt")
        val lines = input.lines().filter { it.isNotBlank() }

        // parse part1 input
        for (line in lines.dropLast(1)) {
            for ((c, num) in line.trim().split(" +".toRegex()).withIndex()) {
                if (numsPartOne.getOrNull(c) == null) numsPartOne.add(mutableListOf())
                numsPartOne[c].add(num.toLong())
            }
        }

        // parse part2 input
        var numList = mutableListOf<Long>()
        for (c in 0..<lines.maxOf { it.length }) {
            var numStr = ""
            for (r in 0..<lines.size - 1) {
                numStr += lines[r].getOrElse(c) { ' ' }
            }
            if (numStr.isBlank()) {
                numsPartTwo.add(numList)
                numList = mutableListOf()
            } else {
                numList.add(numStr.trim().toLong())
            }
        }
        numsPartTwo.add(numList)

        // parse operators
        ops.addAll(
            lines.last().split(" +".toRegex())
                .map { it.trim()[0] }
                .map {
                    when (it) {
                        '*' -> { a: Long, b: Long -> a * b }
                        '+' -> { a: Long, b: Long -> a + b }
                        else -> throw IllegalArgumentException("Unknown operator: $it")
                    }
                }
        )
    }

    override fun solvePartOne(): String {
        return numsPartOne.mapIndexed { c, list -> list.reduce { a, b -> ops[c](a, b) } }.sum().toString()
    }

    override fun solvePartTwo(): String {
        return numsPartTwo.mapIndexed { c, list -> list.reduce { a, b -> ops[c](a, b) } }.sum().toString()
    }
}