import {
	branchPath,
	yearPath,
	monthPath,
	dayPath,
} from "@/lib/frontend/routes";
import { formatMonthLabel } from "@/lib/frontend/explorer/formatters";
import { sortNumericStringsDesc } from "@/lib/frontend/explorer/sorters";

/**
 * normalizeNumericOptions
 *
 * Pure helper:
 * - Ensures array input
 * - Filters empty values
 * - Deduplicates
 * - Sorts descending (latest first) for numeric strings
 *
 * @param {string[]|null|undefined} options
 * @returns {string[]|null}
 */
export function normalizeNumericOptions(options) {
	if (!Array.isArray(options) || options.length === 0) return null;

	const unique = Array.from(
		new Set(options.map((x) => String(x)).filter(Boolean))
	);
	if (unique.length === 0) return null;

	return sortNumericStringsDesc(unique);
}

/**
 * buildExplorerDropdownItems
 *
 * Builds dropdown menu items for year/month/day breadcrumb segments.
 * This function is intentionally pure and React-free to keep it testable.
 *
 * @param {{
 *   branch: string,
 *   year?: string|null,
 *   month?: string|null,
 *   day?: string|null,
 *   yearOptions?: string[]|null,
 *   monthOptions?: string[]|null,
 *   dayOptions?: string[]|null
 * }} input
 * @returns {{
 *   yearItems: Array<{ value: string, label: string, href: string }> | null,
 *   monthItems: Array<{ value: string, label: string, href: string }> | null,
 *   dayItems: Array<{ value: string, label: string, href: string }> | null
 * }}
 */
export function buildExplorerDropdownItems({
	branch,
	year = null,
	month = null,
	day = null,
	yearOptions = null,
	monthOptions = null,
	dayOptions = null,
}) {
	const years = normalizeNumericOptions(yearOptions);
	const months = normalizeNumericOptions(monthOptions);
	const days = normalizeNumericOptions(dayOptions);

	const yearItems =
		year && years
			? years.map((y) => ({
					value: y,
					label: y,
					href: yearPath(branch, y),
			  }))
			: null;

	const monthItems =
		year && month && months
			? months.map((m) => ({
					value: m,
					label: formatMonthLabel(m),
					href: monthPath(branch, year, m),
			  }))
			: null;

	const dayItems =
		year && month && day && days
			? days.map((d) => ({
					value: d,
					label: d,
					href: dayPath(branch, year, month, d),
			  }))
			: null;

	return { yearItems, monthItems, dayItems };
}

/**
 * buildBranchCrumbHref
 *
 * Tiny helper to keep the breadcrumb component simple.
 *
 * @param {string} branch
 * @returns {string}
 */
export function buildBranchCrumbHref(branch) {
	return branchPath(branch);
}