import { open } from "node:fs/promises";

const file = await open("./2024/inputs/6");

const map: string[][] = []
for await (const line of file.readLines()) {
    map.push(line.split(""))
}

type Vector2 = {
    X: number,
    Y: number
}

// 0: UP
// 1: RIGHT
// 2: DOWN
// 3: LEFT

const directions: Vector2[] = [{
    X: 0,
    Y: -1
},
{
    X: 1,
    Y: 0
},
{
    X: 0,
    Y: 1
},
{
    X: -1,
    Y: 0
}]

const height = map.length
const width = map[0].length

let d = 0

const startY = map.findIndex(l => l.includes("^"))
const startX = map[startY].indexOf("^")
const position: Vector2 = {
    X: startX,
    Y: startY
}

function getNextCoordinates(): Vector2 {
    return {
        X: position.X + directions[d].X,
        Y: position.Y + directions[d].Y
    }
}

function getTile({ X, Y }: Vector2) {
    if (X < 0 || Y < 0 || X >= width || Y >= height) {
        return null
    }
    return map[Y][X]
}

function rotate() {
    d = (d + 1) % 4
}

function moveForward() {
    Object.assign(position, getNextCoordinates())
}

while (getTile(getNextCoordinates())) {
    const tile = getTile(getNextCoordinates())
    if (tile == "#") {
        rotate()
    } else {
        moveForward()
    }
    map[position.Y][position.X] = "X"
}

console.log(map.reduce((acc, l) => l.reduce((acc, t) => t == "X" ? acc + 1 : acc, 0) + acc, 0))