import fs from "node:fs";
import { printTime, now } from "../util";

const test = false;

const data = fs.readFileSync(
  test ? "./inputs/testinput" : "./inputs/input",
  "utf8"
);

let timer = now.instant();
console.log(
  "part one:",
  data
    .split("\n")
    .slice(0, -1)
    .reduce((coll, curr, index, array) => {
      // 2D string matching is a pain. Let's turn it into a 1D problem!
      // create the columns
      curr.split("").forEach((s, i) => {
        coll[i] = coll[i] ? coll[i] + s : s;
      });
      // create the down-left-diagonals
      curr.split("").forEach((s, i) => {
        coll[i + array.length + index] = coll[i + array.length + index]
          ? coll[i + array.length + index] + s
          : s;
      });
      // create the down-right-diagonals
      curr.split("").forEach((s, i) => {
        coll[array.length * 4 + index - i - 2] = coll[
          array.length * 4 + index - i - 2
        ]
          ? coll[array.length * 4 + index - i - 2] + s
          : s;
      });
      // include the original row
      return [...coll, curr];
    }, Array.from({ length: test ? 10 + (10 * 4 - 2) : 140 + 140 * 4 - 2 }) as string[])
    .reduce((total, curr) => {
      // and now just do some regexes over the set of 1D strings
      let matchesForward = curr.match(/XMAS/g);
      let matchesBackward = curr.match(/SAMX/g);
      if (matchesForward) {
        total += matchesForward.length;
      }
      if (matchesBackward) {
        total += matchesBackward.length;
      }
      return total;
    }, 0),
  printTime(now.instant().since(timer))
);

timer = now.instant();
console.log(
  "part two:",
  data
    .split("\n")
    .slice(0, -1)
    .reduce((coll, curr, index, array) => {
      if (index === 0 || index === array.length - 1) {
        // we can entirely skip the first and last rows, since there's no way to get a cross started
        return coll;
      }
      // look for A's
      curr.split("").forEach((s, i, a) => {
        if (i === 0 || i === a.length - 1) {
          // same as above, edges are useless
          return;
        }
        if (s === "A") {
          // 1 2
          //  A
          // 3 4
          coll = [
            ...coll,
            array[index - 1][i - 1] +
              array[index - 1][i + 1] +
              array[index + 1][i - 1] +
              array[index + 1][i + 1],
          ];
        }
      });
      return coll;
    }, [] as string[])
    .reduce((coll, curr) => {
      // we could have just done this check above,
      // but it's a little more clear, although slower,
      // to iterate again.
      switch (curr) {
        case "MSMS":
        case "SSMM":
        case "SMSM":
        case "MMSS":
          coll += 1;
        default:
          break;
      }
      return coll;
    }, 0),
  printTime(now.instant().since(timer))
);