import { error } from '@sveltejs/kit';
import { createApiClient } from '$lib/shared/api.server';
import { getErrorMessage } from '$lib/shared/errors';
import { hasWriteAll } from '$lib/shared/server/permissions';

const PAGE_SIZE = 50;

type PersonType = 'PERSON' | 'INSTITUTION' | 'GROUP';

function parseType(raw: string | null): PersonType | undefined {
	return raw === 'PERSON' || raw === 'INSTITUTION' || raw === 'GROUP' ? raw : undefined;
}

export async function load({ url, fetch, locals }) {
	const q = url.searchParams.get('q') || '';
	const page = Math.max(0, Number.parseInt(url.searchParams.get('page') ?? '0', 10) || 0);
	const review =
		url.searchParams.get('review') === '1' || url.searchParams.get('review') === 'true';
	const type = parseType(url.searchParams.get('type'));
	const familyOnly = url.searchParams.get('familyOnly') === 'true';
	const hasDocuments = url.searchParams.get('hasDocuments') === 'true';

	const api = createApiClient(fetch);

	const canWrite = hasWriteAll(locals);

	const filters = {
		q: q || undefined,
		type,
		familyOnly: familyOnly || undefined,
		hasDocuments: hasDocuments || undefined,
		review: review || undefined,
		page,
		size: PAGE_SIZE
	};

	// The "Zu prüfen (N)" link count is the totalElements of a provisional-only query. A size=1
	// page keeps the extra request cheap — we only need the count, not the rows.
	const [personsResult, statsResult, reviewCountResult] = await Promise.all([
		api.GET('/api/persons', { params: { query: filters } }),
		api.GET('/api/stats', {}),
		canWrite
			? api.GET('/api/persons', { params: { query: { provisional: true, review: true, size: 1 } } })
			: Promise.resolve(null)
	]);

	if (!personsResult.response.ok) {
		throw error(personsResult.response.status, getErrorMessage(undefined));
	}

	const result = personsResult.data!;

	const stats = statsResult.response.ok
		? {
				totalPersons: statsResult.data!.totalPersons ?? 0,
				totalDocuments: statsResult.data!.totalDocuments ?? 0
			}
		: { totalPersons: 0, totalDocuments: 0 };

	const needsReviewCount =
		reviewCountResult && reviewCountResult.response.ok
			? (reviewCountResult.data!.totalElements ?? 0)
			: 0;

	return {
		persons: result.items,
		totalElements: result.totalElements,
		totalPages: result.totalPages,
		pageNumber: result.pageNumber,
		pageSize: result.pageSize,
		filters: { type, familyOnly, hasDocuments, review },
		needsReviewCount,
		stats,
		q,
		canWrite
	};
}