package day04

import (
	"regexp"
	"sort"
	"strconv"
	"tools"
)

var roomRegexp = regexp.MustCompile(`^(.*)-([[:digit:]]+)\[(.*)]$`)

func validateChecksum(roomname, checksum string) bool {
	charcount := make(map[int32]int)
	for _, c := range roomname {
		if c != '-' {
			charcount[c]++
		}
	}

	charcountReverse := make(map[int]tools.ByteSlice)
	counts := tools.NewSetInt()
	for c, v := range charcount {
		counts.Add(v)
		charcountReverse[v] = append(charcountReverse[v], byte(c))
	}

	countList := counts.Keys()
	sort.Sort(sort.Reverse(countList))

	calcChecksum := ""
	for _, v := range countList {
		charList := charcountReverse[v]
		sort.Sort(charList)
		for _, c := range charList {
			calcChecksum += string(c)
		}
	}

	return checksum == calcChecksum[:5]
}

func Part1(puzzle tools.AoCPuzzle) interface{} {
	sectorSum := 0
	for _, line := range puzzle.GetInputArray() {
		roomMatches := roomRegexp.FindStringSubmatch(line)
		roomName := roomMatches[1]
		roomSectorId, _ := strconv.Atoi(roomMatches[2])
		roomChecksum := roomMatches[3]

		if validateChecksum(roomName, roomChecksum) {
			sectorSum += roomSectorId
		}
	}

	return sectorSum
}

func Part2(puzzle tools.AoCPuzzle) interface{} {
	for _, line := range puzzle.GetInputArray() {
		roomMatches := roomRegexp.FindStringSubmatch(line)
		roomName := roomMatches[1]
		roomSectorId, _ := strconv.Atoi(roomMatches[2])
		roomChecksum := roomMatches[3]

		if validateChecksum(roomName, roomChecksum) {
			addNum := int32(roomSectorId) % 26
			realName := ""
			for _, c := range roomName {
				switch c {
				case '-':
					realName += " "
				default:
					for c+addNum > 122 {
						c -= 26
					}
					realName += string(c + addNum)
				}
			}
			if realName == "northpole object storage" {
				return roomSectorId
			}
		}
	}

	return -1
}