const fs = require('fs');

const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');

interface Coord {
    x: number,
    y: number,
};

enum Dir {
    Up,
    Right,
    Down,
    Left,
};

const map: Array<Array<string>> = input.split("\n").map((row: string) => row.split(''));

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

const startIndex = input.indexOf('S');
let startPos = { x: startIndex % (width + 1), y: Math.floor(startIndex / height) };

function get(pos: Coord): string {
    if (map[pos.y] && map[pos.y][pos.x]) {
        return map[pos.y][pos.x];
    }
    return '#';
}

function set(pos: Coord, val: string): void {
    map[pos.y][pos.x] = val;
}

function nextDir(dir: Dir): Dir {
    const directions = [Dir.Up, Dir.Right, Dir.Down, Dir.Left];
    const i = (directions.indexOf(dir) + 1) % directions.length;
    return directions[i];
}
function prevDir(dir: Dir): Dir {
    const directions = [Dir.Up, Dir.Right, Dir.Down, Dir.Left];
    const i = directions.indexOf(dir) - 1;
    if (i < 0) {
        return directions[directions.length - 1];
    }
    return directions[i];
}

function nextCoord(pos: Coord, direction: Dir): Coord {
    return direction === Dir.Up ? { x: pos.x, y: pos.y - 1 }
        : (direction === Dir.Right ? { x: pos.x + 1, y: pos.y }
            : (direction === Dir.Down ? { x: pos.x, y: pos.y + 1 } : { x: pos.x - 1, y: pos.y })
        );
}

const shortCuts: Array<number> = [];

const pathCoords: Array<Coord> = [startPos];

const cheatTime = 20;
const minShortCut = 100;

let speedMap: { [key: string]: number } = {};

function findShortCuts(pos: Coord): void {
    for (let i = 0; i < pathCoords.length - minShortCut; i++) {
        const possibleSC = pathCoords[i];
        const dx = possibleSC.x - pos.x;
        const dy = possibleSC.y - pos.y;
        const cheatLength = Math.abs(dx) + Math.abs(dy);
        if (cheatLength <= cheatTime) {
            const shortCutLength = pathCoords.length - i - cheatLength;
            if (shortCutLength >= minShortCut) {
                shortCuts.push(shortCutLength);
            }
        }
    }
}

for (let dir of [Dir.Up, Dir.Right, Dir.Down, Dir.Left]) {
    if (get(nextCoord(startPos, dir)) === '.') {
        let pos = startPos;
        loop:
        while (true) {
            for (let newDir of [dir, nextDir(dir), prevDir(dir)]) {
                const next = nextCoord(pos, newDir);
                const nextStr = `${next.x},${next.y}`;
                const nextChar = get(next);
                if (nextChar === 'E') {
                    findShortCuts(next);
                    pathCoords.push(next);
                    break loop;
                } else if (nextChar === '.') {
                    findShortCuts(next);
                    pathCoords.push(next);
                    pos = next;
                    dir = newDir;
                    break;
                }
            };
        }
        break;
    }
}

console.log(shortCuts.length);