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 org.eclipse.collections.api.factory.Bags
import org.eclipse.collections.api.multimap.set.MutableSetMultimap
import org.eclipse.collections.impl.factory.Multimaps

@Day(21)
class Day21(@Lines val input: Input<List<String>>) {
    private val foods = input.value.map { line ->
        val parOpen = line.indexOf('(')
        val ingredients = line.substring(0 until parOpen - 1).split(" ")
        val allergens = line.substring(parOpen + 1 until line.length - 1).removePrefix("contains ").split(", ")
        ingredients to allergens
    }

    private val allIngredients = foods.flatMap { it.first }.toSet()
    private val allAllergens = foods.flatMap { it.second }.toSet()
    private val dangerousIngredients = dangerousIngredients()

    fun part1(): Int {
        val occurrences = Bags.mutable.empty<String>()
        foods.forEach { (ingredients) -> occurrences.addAll(ingredients) }
        return allIngredients.filter { !dangerousIngredients.containsValue(it) }
            .map { ingredient -> occurrences.count { it == ingredient } }
            .sum()
    }

    fun part2(): String {
        while (!dangerousIngredients.multiValuesView().all { it.size() == 1 }) {
            dangerousIngredients.multiValuesView()
                .filter { it.size() == 1 }
                .map { it.first() }
                .forEach { removeMe ->
                    dangerousIngredients.keyMultiValuePairsView()
                        .filter { it.two.size() != 1 && it.two.contains(removeMe) }
                        .forEach { dangerousIngredients.remove(it.one, removeMe) }
                }
        }
        return dangerousIngredients.keySet().sorted().joinToString(",") { dangerousIngredients.get(it).first() }
    }

    private fun dangerousIngredients(): MutableSetMultimap<String, String> {
        val map = Multimaps.mutable.set.empty<String, String>()
        allAllergens.forEach { map.putAll(it, allIngredients) }

        foods.forEach { (ingredients, allergens) ->
            allergens.forEach { allergen ->
                allIngredients.forEach {
                    if (!ingredients.contains(it)) map.remove(allergen, it)
                }
            }
        }
        return map
    }
}