import fs from "node:fs";

const data = fs.readFileSync("./inputs/input", "utf8");

type collector = { ok: boolean; inc: boolean; dec: boolean };

const init = {
  ok: true,
  inc: false,
  dec: false,
};

const reducer = (col: collector, curr: number, i: number, a: number[]) =>
  i === 0 || !col.ok
    ? col
    : {
        ok:
          a[i - 1] - curr > -4 && a[i - 1] - curr !== 0 && a[i - 1] - curr < 4,
        inc: col.inc || a[i - 1] - curr > 0,
        dec: col.dec || a[i - 1] - curr < 0,
      };

const isOK = (r: collector): boolean => r.ok && !(r.inc && r.dec);

const permute = (report: number[]): number[][] => {
  return Array.from({ length: report.length }, (_, i) => [
    ...report.slice(0, i),
    ...report.slice(i + 1),
  ]);
};

console.log(
  "part one:",
  data
    .split("\n")
    .slice(0, -1) // remove empty trailing newline
    .map((v) => v.split(" ").map((c) => parseInt(c, 10)))
    .reduce(
      (total, current) =>
        isOK(current.reduce(reducer, init)) ? total + 1 : total,
      0
    )
);

console.log(
  "part two:",
  data
    .split("\n")
    .slice(0, -1) // remove empty trailing newline
    .map((v) => v.split(" ").map((c) => parseInt(c, 10)))
    .reduce(
      (total, current) =>
        isOK(current.reduce(reducer, init)) ||
        permute(current)
          .map((v) => v.reduce(reducer, init))
          .reduce((coll, curr) => coll || isOK(curr), false)
          ? total + 1
          : total,
      0
    )
);