/**
 * Built-in views over a library.
 *
 * These are navigation, not content — a fixed set of lenses every library has,
 * as distinct from shelves, which are named collections a user owns. Nothing
 * here is persisted or user-editable.
 *
 * Defined once and consumed twice: the home route renders them as shelves, and
 * the library view renders them as chips. Previously each home shelf was a
 * hand-written query string in the loader, which is how `create_at` (missing a
 * `d`) went unnoticed — that sort silently did nothing.
 */

export interface BookPreset {
	id: string;
	label: string;
	/** Shown as the shelf heading on the home page. */
	heading: string;
	/** Filter values, keyed the way the books endpoint expects them. */
	filters: Record<string, string[]>;
	/** Backend sort field; omitted means "leave the current ordering alone". */
	orderBy?: string;
	/** asc, desc, or random — the API's CustomOrderBy accepts all three. */
	sortOrder?: string;
}

export const BOOK_PRESETS: BookPreset[] = [
	{
		id: 'continue-reading',
		label: 'Reading',
		heading: 'Continue Reading',
		filters: { progress: ['in_progress'] },
		orderBy: 'last_accessed',
		sortOrder: 'desc'
	},
	{
		id: 'recently-added',
		label: 'Recently added',
		heading: 'Recently Added',
		filters: { progress: ['unread'] },
		orderBy: 'created_at',
		sortOrder: 'desc'
	},
	{
		id: 'discover',
		label: 'Discover',
		heading: 'Discover',
		filters: { progress: ['unread'] },
		sortOrder: 'random'
	},
	{
		id: 'read-again',
		label: 'Read again',
		heading: 'Read Again',
		filters: { progress: ['read'] },
		sortOrder: 'random'
	}
];

export function getPreset(id: string) {
	return BOOK_PRESETS.find((preset) => preset.id === id);
}

/**
 * Query string for the books endpoint, used by the home route's loader.
 */
export function presetQuery(preset: BookPreset, libraryId: string | number) {
	const params = new URLSearchParams();
	params.set('libraries', String(libraryId));

	for (const [key, values] of Object.entries(preset.filters)) {
		for (const value of values) params.append(key, value);
	}

	if (preset.orderBy) params.set('orderBy', preset.orderBy);
	if (preset.sortOrder) params.set('sortOrder', preset.sortOrder);

	return params.toString();
}