import { useCallback, useEffect, useMemo, useState } from 'react';
import { useAtelierClient } from '../lib/api';
import type { CollectionSummary } from '../lib/api';

/**
 * The collection LIST — no detail view any more.
 *
 * A selected collection is rendered by the Gallery panel, which reads the same `?collection=` param.
 * This hook stopped fetching the detail when that moved: two panels both holding a copy of one
 * collection's images is two things to keep in step, and the narrow list has no use for them.
 */
export const useCollectionsManager = () => {
  const client = useAtelierClient();
  const [collections, setCollections] = useState<CollectionSummary[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [query, setQuery] = useState('');

  const refresh = useCallback(async () => {
    try {
      setCollections(await client.listCollections());
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    } finally {
      setLoading(false);
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  useEffect(() => {
    void refresh();
  }, [refresh]);

  // Filtering happens here rather than server-side: the list is small enough that a round trip per
  // keystroke would be slower than the filter, and a search that cannot go stale needs no refresh.
  const visible = useMemo(() => {
    const needle = query.trim().toLowerCase();
    if (!needle) return collections;
    return collections.filter((collection) => collection.name.toLowerCase().includes(needle));
  }, [collections, query]);

  const guard = async (action: () => Promise<unknown>) => {
    try {
      await action();
      setError(null);
      await refresh();
      return true;
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
      return false;
    }
  };

  return {
    collections: visible,
    total: collections.length,
    loading,
    error,
    query,
    setQuery,
    refresh,
    create: (name: string) => guard(() => client.createCollection(name.trim())),
    rename: (id: string, name: string) => guard(() => client.renameCollection(id, name.trim())),
    remove: (id: string, deleteImages: boolean) => guard(() => client.deleteCollection(id, deleteImages)),
  };
};

export type CollectionsManager = ReturnType<typeof useCollectionsManager>;