package be.vandewalleh.aoc.days

import be.vandewalleh.aoc.utils.BaseDay
import be.vandewalleh.aoc.utils.input.Day

@Day
class Day10 : BaseDay() {
    private val chunks = mapOf(
        ')' to '(',
        ']' to '[',
        '>' to '<',
        '}' to '{',
    )

    override fun part1(): Any {
        val points = mapOf(
            ')' to 3,
            ']' to 57,
            '}' to 1197,
            '>' to 25137,
        )
        return input.lines.value.sumOf { line ->
            val stack = mutableListOf<Char>()
            for (char in line) {
                if (char in chunks) {
                    if (stack.last() == chunks[char]!!) stack.removeLast()
                    else return@sumOf points[char]!!
                } else {
                    stack.add(char)
                }
            }
            0
        }
    }

    override fun part2(): Any {
        val points = mapOf(
            '(' to 1,
            '[' to 2,
            '{' to 3,
            '<' to 4,
        )
        return input.lines.value.mapNotNull { line ->
            val stack = mutableListOf<Char>()
            for (char in line) {
                if (char in chunks) {
                    if (stack.last() == chunks[char]!!) stack.removeLast()
                    else return@mapNotNull null
                } else {
                    stack.add(char)
                }
            }
            stack.asReversed().fold(0L) { score, char -> score * 5 + points[char]!! }
        }.sorted().let { it[it.size / 2] }
    }
}