import { redirect } from '@sveltejs/kit';
import { createApiClient } from '$lib/api.server';
import type { components } from '$lib/generated/api';

type IncompleteDocumentDTO = components['schemas']['IncompleteDocumentDTO'];
type StatsDTO = components['schemas']['StatsDTO'];
type Document = components['schemas']['Document'];
type SearchMatchData = components['schemas']['SearchMatchData'];

export async function load({ url, fetch }) {
	const q = url.searchParams.get('q') || '';
	const from = url.searchParams.get('from') || '';
	const to = url.searchParams.get('to') || '';
	const senderId = url.searchParams.get('senderId') || '';
	const receiverId = url.searchParams.get('receiverId') || '';
	const tags = url.searchParams.getAll('tag');
	const VALID_SORTS = ['DATE', 'TITLE', 'SENDER', 'RECEIVER', 'UPLOAD_DATE'] as const;
	type ValidSort = (typeof VALID_SORTS)[number];
	const rawSort = url.searchParams.get('sort') ?? 'DATE';
	const sort: ValidSort = (VALID_SORTS as readonly string[]).includes(rawSort)
		? (rawSort as ValidSort)
		: 'DATE';
	const VALID_DIRS = ['asc', 'desc'] as const;
	type ValidDir = (typeof VALID_DIRS)[number];
	const rawDir = url.searchParams.get('dir') ?? 'desc';
	const dir: ValidDir = (VALID_DIRS as readonly string[]).includes(rawDir)
		? (rawDir as ValidDir)
		: 'desc';
	const tagQ = url.searchParams.get('tagQ') || '';

	const isDashboard = !q && !from && !to && !senderId && !receiverId && !tags.length && !tagQ;

	const api = createApiClient(fetch);

	try {
		const [docsResult, personsResult] = await Promise.all([
			isDashboard
				? Promise.resolve(null)
				: api.GET('/api/documents/search', {
						params: {
							query: {
								q: q || undefined,
								from: from || undefined,
								to: to || undefined,
								senderId: senderId || undefined,
								receiverId: receiverId || undefined,
								tag: tags.length ? tags : undefined,
								tagQ: tagQ || undefined,
								sort,
								dir: dir || undefined
							}
						}
					}),
			api.GET('/api/persons')
		]);

		if (personsResult.response.status === 401) {
			throw redirect(302, '/login');
		}
		if (docsResult && docsResult.response.status === 401) {
			throw redirect(302, '/login');
		}

		const searchResult = docsResult?.data as {
			documents?: Document[];
			total?: number;
			matchData?: Record<string, SearchMatchData>;
		} | null;
		const documents: Document[] = searchResult?.documents ?? [];
		const total: number = searchResult?.total ?? 0;
		const matchData: Record<string, SearchMatchData> = searchResult?.matchData ?? {};
		const allPersons = (personsResult.data ?? []) as {
			id: string;
			firstName: string;
			lastName: string;
		}[];

		const senderObj = allPersons.find((p) => p.id === senderId);
		const receiverObj = allPersons.find((p) => p.id === receiverId);

		// Dashboard widgets — failures are isolated and don't crash the page
		let stats: StatsDTO | null = null;
		let incompleteDocs: IncompleteDocumentDTO[] = [];
		let recentDocs: Document[] = [];

		if (isDashboard) {
			const [statsResult, incompleteResult, recentResult] = await Promise.allSettled([
				api.GET('/api/stats'),
				api.GET('/api/documents/incomplete', { params: { query: { size: 3 } } }),
				api.GET('/api/documents/recent-activity', { params: { query: { size: 5 } } })
			]);

			if (statsResult.status === 'fulfilled' && statsResult.value.response.ok) {
				stats = statsResult.value.data ?? null;
			}
			if (incompleteResult.status === 'fulfilled' && incompleteResult.value.response.ok) {
				incompleteDocs = incompleteResult.value.data ?? [];
			}
			if (recentResult.status === 'fulfilled' && recentResult.value.response.ok) {
				recentDocs = recentResult.value.data ?? [];
			}
		}

		return {
			isDashboard,
			documents,
			total,
			matchData,
			stats,
			incompleteDocs,
			recentDocs,
			initialValues: {
				senderName: senderObj?.displayName ?? '',
				receiverName: receiverObj?.displayName ?? ''
			},
			filters: { q, from, to, senderId, receiverId, tags, sort, dir, tagQ },
			error: null as string | null
		};
	} catch (e) {
		if ((e as { status?: number }).status) throw e;
		console.error('Error loading data:', e);
		return {
			isDashboard,
			documents: [],
			total: 0,
			matchData: {} as Record<string, SearchMatchData>,
			stats: null,
			incompleteDocs: [],
			recentDocs: [],
			initialValues: { senderName: '', receiverName: '' },
			filters: { q, from, to, senderId, receiverId, tags, sort, dir, tagQ },
			error: 'Daten konnten nicht geladen werden.' as string | null
		};
	}
}