import { DateTime } from "luxon";

export default function (eleventyConfig) {
	/* Create a single alt string from a multi-string alt object */
	eleventyConfig.addFilter("createAlt", (altObject) => {
		let alt;

		if (altObject.length > 1)
			alt = `a ${altObject.length} picture collage.`;
		for (let i = 0; i < altObject.length; i++)
			alt += ` Image ${i + 1} is ${altObject[i]}`;

		return alt;
	});

	/* For <time> elements */
	eleventyConfig.addFilter("htmlDateString", (dateObj) => {
		return DateTime.fromJSDate(dateObj, { zone: "utc" }).toFormat("yyyy-LL-dd");
	});

	/* What it says on the tin */
	eleventyConfig.addFilter("randomize", function(array) {
		// Create a copy of the array to avoid modifying the original
		let shuffledArray = array.slice();

		// Fisher-Yates shuffle algorithm
		for (let i = shuffledArray.length - 1; i > 0; i--) {
				const j = Math.floor(Math.random() * (i + 1));
				[shuffledArray[i], shuffledArray[j]] = [shuffledArray[j], shuffledArray[i]];
		}

		return shuffledArray;
	});

	/* Sort alphabetically by item title */
	eleventyConfig.addFilter("sortAlphabeticallyByTitle", collection => {
		collection.sort((b, a) => b.data.title.localeCompare(a.data.title));
		return collection;
	});
};