import { useState, useEffect } from 'react';
import { RxCollection } from 'rxdb';
import useRxDB from './useRxDB';

function useRxCollection<T>(name: string): RxCollection<T> | null {
	const [collection, setCollection] = useState<RxCollection<T> | null>(null);
	const db = useRxDB();

	useEffect(() => {
		if (!db) {
			return;
		}
		const found = db[name];
		if (found) {
			setCollection(found);
		}
		if (db.newCollections$) {
			const sub = db.newCollections$.subscribe(col => {
				if (col[name]) {
					// We don't unsubscribe so that we get notified
					// and update collection if it gets deleted/recreated
					setCollection(col[name]);
				}
			});
			return () => {
				sub.unsubscribe();
			};
		}
	}, [db, name]);

	return collection;
}

export default useRxCollection;