--- Day 4: Ceres Search ---

"Looks like the Chief's not here. Next!" One of The Historians pulls out a device and pushes the only button on it. After a brief flash, you recognize the interior of the Ceres monitoring station!

As the search for the Chief continues, a small Elf who lives on the station tugs on your shirt; she'd like to know if you could help her with her word search (your puzzle input). She only has to find one word: XMAS.

This word search allows words to be horizontal, vertical, diagonal, written backwards, or even overlapping other words. It's a little unusual, though, as you don't merely need to find one instance of XMAS - you need to find all of them. Here are a few ways XMAS might appear, where irrelevant characters have been replaced with .:

..X...
.SAMX.
.A..A.
XMAS.S
.X....
The actual word search will be full of letters instead. For example:

MMMSXXMASM
MSAMXMSMSA
AMXSXMAAMM
MSAMASMSMX
XMASAMXAMM
XXAMMXXAMA
SMSMSASXSS
SAXAMASAAA
MAMMMXMMMM
MXMXAXMASX
In this word search, XMAS occurs a total of 18 times; here's the same word search again, but where letters not involved in any XMAS have been replaced with .:

....XXMAS.
.SAMXMS...
...S..A...
..A.A.MS.X
XMASAMX.MM
X.....XA.A
S.S.S.S.SS
.A.A.A.A.A
..M.M.M.MM
.X.X.XMASX
Take a look at the little Elf's word search. How many times does XMAS appear?

Your puzzle answer was 2434.

--- Part Two ---

The Elf looks quizzically at you. Did you misunderstand the assignment?

Looking for the instructions, you flip over the word search to find that this isn't actually an XMAS puzzle; it's an X-MAS puzzle in which you're supposed to find two MAS in the shape of an X. One way to achieve that is like this:

M.S
.A.
M.S
Irrelevant characters have again been replaced with . in the above diagram. Within the X, each MAS can be written forwards or backwards.

Here's the same example from before, but this time all of the X-MASes have been kept instead:

.M.S......
..A..MSMS.
.M.S.MAA..
..A.ASMSM.
.M.S.M....
..........
S.S.S.S.S.
.A.A.A.A..
M.M.M.M.M.
..........
In this example, an X-MAS appears 9 times.

Flip the word search from the instructions back over to the word search side and try again. How many times does an X-MAS appear?
const fs = require('fs');

// Function to read the input file and split it into rows
function readInput(filePath) {
  try {
    const data = fs.readFileSync(filePath, 'utf-8');
    return data.split("\n").filter(row => row.length > 0);  // Filter out any empty rows
  } catch (error) {
    console.error('Error reading the file:', error);
    return [];
  }
}

// Function to check if an "X-MAS" pattern is found at a given position in the grid
function isXMASPattern(rows, rowIndex, colIndex, WIDTH, HEIGHT) {
  // Check if we're within bounds and the letter at the center is 'A'
  if (rowIndex > 0 && rowIndex < HEIGHT - 1 && colIndex > 0 && colIndex < WIDTH - 1 && rows[rowIndex][colIndex] === 'A') {
    return (
      // Check for diagonals forming 'X-MAS' in both directions
      (
        rows[rowIndex + 1][colIndex + 1] === 'M' && rows[rowIndex - 1][colIndex - 1] === 'S' ||
        rows[rowIndex + 1][colIndex + 1] === 'S' && rows[rowIndex - 1][colIndex - 1] === 'M'
      ) &&
      (
        rows[rowIndex + 1][colIndex - 1] === 'M' && rows[rowIndex - 1][colIndex + 1] === 'S' ||
        rows[rowIndex + 1][colIndex - 1] === 'S' && rows[rowIndex - 1][colIndex + 1] === 'M'
      )
    );
  }
  return false;
}

// Function to count occurrences of the "X-MAS" pattern in the grid
function countXMASPatterns(rows, WIDTH, HEIGHT) {
  let runningTotal = 0;

  // Loop over each row and column to check for "X-MAS" patterns
  rows.forEach((row, rowIndex) => {
    [...row].forEach((letter, colIndex) => {
      if (isXMASPattern(rows, rowIndex, colIndex, WIDTH, HEIGHT)) {
        runningTotal++;
      }
    });
  });

  return runningTotal;
}

// Main function to orchestrate the entire process
function main() {
  const rows = readInput('input.txt');
  if (rows.length === 0) return;

  const WIDTH = rows[0].length;
  const HEIGHT = rows.length;

  // Count the occurrences of "X-MAS" patterns
  const totalPatterns = countXMASPatterns(rows, WIDTH, HEIGHT);

  // Output the result
  console.log(totalPatterns);
}

main();  // Run the main function