package be.vandewalleh.aoc.days

import be.vandewalleh.aoc.utils.input.Day
import be.vandewalleh.aoc.utils.input.Input
import be.vandewalleh.aoc.utils.input.Lines
import be.vandewalleh.aoc.utils.input.createDay
import org.eclipse.collections.impl.factory.primitive.IntLists
import org.eclipse.collections.impl.factory.primitive.IntSets

@Day(8)
class Day08(@Lines val input: Input<List<String>>) {

    private val instructions = input.value
        .map {
            val words = it.split(" ")
            Instruction(Operation.valueOf(words[0].capitalize()), words[1].toInt())
        }.toTypedArray()

    fun part1() = run(instructions)

    private fun run(mutatedInstructions: Array<Instruction>): Int {
        var acc = 0
        var ptr = 0

        val visited = IntSets.mutable.empty()

        while (visited.add(ptr)) {
            val instruction = mutatedInstructions[ptr]
            when (instruction.operation) {
                Operation.Acc -> {
                    acc += instruction.argument
                    ptr++
                }
                Operation.Jmp -> ptr += instruction.argument
                Operation.Nop -> ptr++
            }
            if (ptr !in mutatedInstructions.indices) {
                println(acc)
                error("oob")
            }
        }

        return acc
    }

    fun part2() {
        val possibleMutations = IntLists.mutable.empty()
        instructions.forEachIndexed { i, e ->
            if (e.operation != Operation.Acc) possibleMutations.add(i)
        }

        possibleMutations.forEach { index ->
            val copy = instructions.clone().also {
                val modifiedOperation = if (it[index].operation == Operation.Nop) Operation.Jmp else Operation.Nop
                it[index] = it[index].copy(operation = modifiedOperation)
            }
            run(copy)
        }
    }

}

enum class Operation { Acc, Jmp, Nop }

data class Instruction(val operation: Operation, val argument: Int)

fun main() {
    val day = createDay<Day08>()
    println(day.part1())
    println(day.part2())
}