"use strict";

import { readFile } from "fs/promises";

if (process.argv.length <= 2) {
	console.error(`Needs more args >:(`).
	process.exit(0);
}

const fileToRead = process.argv[2];
const file = await readFile(fileToRead, `utf-8`);

/** @type {Array<Array<string>>} */
const wordSearch = [];
const wordToLookFor = "XMAS"

for (const line of file.split(`\n`)) {
	wordSearch.push(line.split(``));
};

const locationTransformers = {
	north: ([y, x], i) => [y - i, x],
	northeast: ([y, x], i) => [y - i, x + i],
	east: ([y, x], i) => [y, x + i],
	southeast: ([y, x], i) => [y + i, x + i],
	south: ([y, x], i) => [y + i, x],
	southwest: ([y, x], i) => [y + i, x - i],
	west: ([y, x], i) => [y, x - i],
	northwest: ([y, x], i) => [y - i, x - i],
}

let total = 0;

// Iterating the puzzle space
for (let y = 0, l1 = wordSearch.length; y < l1; y++) {
	for (let x = 0, l2 = wordSearch[y].length; x < l2; x++) {


		// Short-circuit for performance
		const middle = wordSearch[y][x];
		if (wordToLookFor.at(0) !== middle) {
			continue;
		};

		const valid = {
			north: true,
			northeast: true,
			east: true,
			southeast: true,
			south: true,
			southwest: true,
			west: true,
			northwest: true,
		};

		// Compare each direction against the letters in the word.
		for (const i in wordToLookFor) {
			const required = wordToLookFor.at(i);

			// Convert the coordinates for each direction then compare
			for (const direction in locationTransformers) {
				if (!valid[direction]) continue;
				const [ newY, newX ] = locationTransformers[direction](
					[y, x],
					parseInt(i)
				);

				try {
					valid[direction] = wordSearch[newY][newX] === required;
				} catch {
					valid[direction] = false;
				};
			};
		};

		total += Object.values(valid).filter(v => v).length;
	};
};

console.log(`Found ${total} instances of ${wordToLookFor}`);