package day14

import (
	"crypto/md5"
	"fmt"
	"strconv"
	"tools"
)

func generateHashes(hashmap map[int][]byte, salt string, start, end int, stretch bool) map[int][]byte {
	for i := start; i <= end; i++ {
		thisSalt := salt + strconv.Itoa(i)
		if _, ok := hashmap[i]; ok {
			continue
		}

		if !stretch {
			hashmap[i] = []byte(fmt.Sprintf("%x", md5.Sum([]byte(thisSalt))))
		} else {
			hash := fmt.Sprintf("%x", md5.Sum([]byte(thisSalt)))
			for i := 0; i < 2016; i++ {
				hash = fmt.Sprintf("%x", md5.Sum([]byte(hash)))
			}
			hashmap[i] = []byte(hash)
		}
	}

	return hashmap
}

func getIndexForKeys(salt string, needKeys int, stretch bool) int {
	hashmap := make(map[int][]byte)

	keyCount := 0
	index := -1
	for keyCount < needKeys {
		index++
		hashmap = generateHashes(hashmap, salt, index, index+1000, stretch)
		foundKey := false
		for i := 0; i < len(hashmap[index])-2; i++ {
			c := hashmap[index][i]
			if c == hashmap[index][i+1] && c == hashmap[index][i+2] {
				for j := 1; j <= 1000; j++ {
					hash := hashmap[index+j]
					for k := 1; k < len(hash)-5; k++ {
						if c != hash[k] {
							continue
						}
						if hash[k+1] == c && hash[k+2] == c && hash[k+3] == c && hash[k+4] == c {
							foundKey = true
							keyCount++
							break
						}
					}
				}
				break
			}
			if foundKey {
				break
			}
		}
	}

	return index
}

func Part1(puzzle tools.AoCPuzzle) interface{} {
	salt := puzzle.GetInputArray()[0]

	return getIndexForKeys(salt, 64, false)
}

func Part2(puzzle tools.AoCPuzzle) interface{} {
	salt := puzzle.GetInputArray()[0]

	return getIndexForKeys(salt, 64, true)
}