import { __ } from '@wordpress/i18n';

/**
 * An ordering of gallery images: the field to order by and the direction.
 */
export type Order = {
	orderby: string;
	order: string;
};

/**
 * The composite `"orderby/order"` select value for an order. A select needs one
 * string per option, so this format exists only at the select boundary; the
 * rest of the feature passes `Order` objects.
 *
 * @param order The order.
 * @return The select value.
 */
export function toOrderValue( order: Order ): string {
	return `${ order.orderby }/${ order.order }`;
}

/**
 * Parses a composite `"orderby/order"` select value back into an order.
 *
 * @param value The select value.
 * @return The order.
 */
export function parseOrderValue( value: string ): Order {
	const [ orderby, order ] = value.split( '/' );
	return { orderby, order };
}

/**
 * Ordering options offered for gallery images. Each value is a composite
 * `orderby/order` string. The two modes share values and labels but differ
 * in their comparison logic:
 *
 * - A dynamic gallery passes `orderby/order` to the REST API in the editor (the
 *   `/wp/v2/media` collection params; see `dynamic-source.js`) and to a
 *   `WP_Query` on the front end (see `index.php`). Either way the database
 *   orders by post date or post title.
 * - A static gallery orders its inner image blocks client-side from the same
 *   attachment fields (see `order-images.js`). Dates compare the same way.
 *   Titles use a natural, case-insensitive compare, so `IMG_2` sorts before
 *   `IMG_10` where the database would put it after. The two title orders can
 *   therefore differ for numbered titles.
 *
 * `menu_order` is deliberately omitted — it isn't a valid REST `orderby`
 * value, so the editor preview couldn't reproduce it (see `dynamic-source.js`).
 */
export const ORDER_OPTIONS = [
	{ label: __( 'Newest to oldest' ), value: 'date/desc' },
	{ label: __( 'Oldest to newest' ), value: 'date/asc' },
	{
		/* translators: Label for ordering images by title in ascending order. */
		label: __( 'A → Z' ),
		value: 'title/asc',
	},
	{
		/* translators: Label for ordering images by title in descending order. */
		label: __( 'Z → A' ),
		value: 'title/desc',
	},
];

/**
 * The "Random" order. Unlike the orders above it isn't an `orderby`: it is the
 * gallery's `randomOrder` attribute, applied only on the front end by shuffling
 * the rendered images (see `index.php`), so the editor keeps showing the
 * underlying order. Offered as the last option of both modes' "Order by"
 * control, since it overrides whatever other order is in place.
 */
export const RANDOM_ORDER = 'random';
export const RANDOM_OPTION = { label: __( 'Random' ), value: RANDOM_ORDER };