package main

import (
	"fmt"
	"os"
	"strings"
)

func readFile(f string) [][]string {
	file, err := os.ReadFile(f)
	if err != nil {
		panic(err)
	}
	ret := [][]string{}
	for _, line := range strings.Split(string(file), "\n") {
		ret = append(ret, strings.Split(line, ""))
	}
	return ret
}


func lookAround(l [][]string, y int, x int) int {
	yToCheck := []int{(y-1), y, (y+1)}
	xToCheck := []int{(x-1), x, (x+1)}
	numNearby := 0
	for _, curY := range yToCheck {
		if curY < 0 || curY > (len(l)-1) {
			continue
		}
		for _, curX := range xToCheck {
			if curX < 0 || curX > (len(l[curY])-1) {
				continue
			}
			if curX == x && curY == y {
				continue
			}
			if l[curY][curX] == "@" {
				numNearby++
			}
		}
	}
	return numNearby
}

func removeRolls (l [][]string, toRemove [][]int) [][]string {
	for _, r := range toRemove {
		l[r[0]][r[1]] = "x"
	}
	return l
}

func runForklift (l [][]string) (int,[][]string) {
	rollsToRemove := [][]int{}
	numReachable := 0
	for y := range l {
		for x := range l[y] {
			if l[y][x] != "@"{
				continue
			} else if lookAround(l, y, x) < 4 {
				numReachable++
				rollsToRemove = append(rollsToRemove, []int{y,x})
			}
		}
	}
	return numReachable, removeRolls(l, rollsToRemove)
}

func partOne() (int) {
	input := readFile("input.txt")
	numReachable := 0
	for y := range input {
		for x := range input[y] {
			if input[y][x] == "."{
				continue
			} else if lookAround(input, y, x) < 4 {
				numReachable++
			}
		}
	}
	return numReachable
}

func partTwo() int {
	input := readFile("input.txt")
	num := 0
	numReachable := -1
	for numReachable != 0 {
		if numReachable != -1 {
			num += numReachable
		}
		numReachable = 0
		numReachable, input = runForklift(input)
	}
	num += numReachable
	return num
}

func main() {
	fmt.Println(partOne())
	fmt.Println(partTwo())
}