package day04

import (
	"strconv"
	"strings"
)

type Solver struct {
	elfPairs []ElfPair
}

type ElfPair struct {
	first, second map[int]bool
}

func (s *Solver) ParseInput(input []string) {
	s.elfPairs = make([]ElfPair, len(input))

	for pairIndex, line := range input {
		pairs := strings.Split(line, ",")

		var i, j int

		p1 := strings.Split(pairs[0], "-")
		m1 := make(map[int]bool)

		i, _ = strconv.Atoi(p1[0])
		j, _ = strconv.Atoi(p1[1])
		for ; i <= j; i++ {
			m1[i] = true
		}

		p2 := strings.Split(pairs[1], "-")
		m2 := make(map[int]bool)

		i, _ = strconv.Atoi(p2[0])
		j, _ = strconv.Atoi(p2[1])
		for ; i <= j; i++ {
			m2[i] = true
		}

		s.elfPairs[pairIndex] = ElfPair{m1, m2}
	}
}

func (s *Solver) SolvePart1() any {
	var total int

	for _, ep := range s.elfPairs {
		if contains(ep.first, ep.second) || contains(ep.second, ep.first) {
			total += 1
		}
	}

	return total
}

func (s *Solver) SolvePart2() any {
	var total int

	for _, ep := range s.elfPairs {
		if len(intersect(ep.first, ep.second)) > 0 {
			total += 1
		}
	}

	return total
}

func contains(m1, m2 map[int]bool) bool {
	for k := range m1 {
		if _, ok := m2[k]; !ok {
			return false
		}
	}
	return true
}

func intersect(m1, m2 map[int]bool) []int {
	result := make([]int, 0)
	for k := range m1 {
		if _, ok := m2[k]; ok {
			result = append(result, k)
		}
	}
	return result
}