export const SEARCH_RESULTS_SORT = Object.freeze({
	RELEVANCE: "relevance",
	DATE_DESC: "date_desc",
	FILENAME_ASC: "filename_asc",
});

function pad2(value) {
	return String(value || "").padStart(2, "0");
}

/**
 * Build an ISO-like date key (YYYY-MM-DD) from a search item.
 *
 * Note:
 * - The backend guarantees year/month/day for search items.
 * - We still keep this defensive to avoid runtime crashes on malformed items.
 *
 * @param {any} item
 * @returns {string}
 */
export function toSearchItemIsoDateKey(item) {
	const y = String(item?.year || "");
	const m = pad2(item?.month);
	const d = pad2(item?.day);
	return `${y}-${m}-${d}`;
}

/**
 * Format the search item date as German UI string: DD.MM.YYYY
 *
 * @param {any} item
 * @returns {string}
 */
export function formatSearchItemDateDe(item) {
	const y = String(item?.year || "");
	const m = pad2(item?.month);
	const d = pad2(item?.day);
	return `${d}.${m}.${y}`;
}

/**
 * Sort search items according to the selected sort mode.
 *
 * Policy:
 * - RELEVANCE: keep backend order (we return a shallow copy to avoid accidental mutation)
 * - DATE_DESC: newest date first, then filename asc (stable & predictable)
 * - FILENAME_ASC: filename asc
 *
 * @param {any[]} items
 * @param {"relevance"|"date_desc"|"filename_asc"|string} sortMode
 * @returns {any[]}
 */
export function sortSearchItems(items, sortMode) {
	const arr = Array.isArray(items) ? [...items] : [];

	if (sortMode === SEARCH_RESULTS_SORT.RELEVANCE) return arr;

	if (sortMode === SEARCH_RESULTS_SORT.DATE_DESC) {
		return arr.sort((a, b) => {
			const da = toSearchItemIsoDateKey(a);
			const db = toSearchItemIsoDateKey(b);

			if (da !== db) return da < db ? 1 : -1;

			const fa = String(a?.filename || "");
			const fb = String(b?.filename || "");
			return fa.localeCompare(fb, "de");
		});
	}

	if (sortMode === SEARCH_RESULTS_SORT.FILENAME_ASC) {
		return arr.sort((a, b) =>
			String(a?.filename || "").localeCompare(String(b?.filename || ""), "de")
		);
	}

	// Unknown sort mode => fail-safe to backend order.
	return arr;
}