fix(frontend): check if swr is validating to determine if we should fetch new data

fixes #719

src/components/MovieDetails/MovieRecommendations.tsx

@@ -1,5 +1,5 @@
 import React, { useContext } from 'react';
-import useSWR, { useSWRInfinite } from 'swr';
+import useSWR from 'swr';
 import type { MovieResult } from '../../../server/models/Search';
 import ListView from '../Common/ListView';
 import { useRouter } from 'next/router';
@@ -7,75 +7,38 @@ import Header from '../Common/Header';
 import type { MovieDetails } from '../../../server/models/Movie';
 import { LanguageContext } from '../../context/LanguageContext';
 import { defineMessages, useIntl, FormattedMessage } from 'react-intl';
-import useSettings from '../../hooks/useSettings';
-import { MediaStatus } from '../../../server/constants/media';
 import PageTitle from '../Common/PageTitle';
+import useDiscover from '../../hooks/useDiscover';
+import Error from '../../pages/_error';
 
 const messages = defineMessages({
   recommendations: 'Recommendations',
   recommendationssubtext: 'If you liked {title}, you might also like…',
 });
 
-interface SearchResult {
-  page: number;
-  totalResults: number;
-  totalPages: number;
-  results: MovieResult[];
-}
-
 const MovieRecommendations: React.FC = () => {
-  const settings = useSettings();
   const intl = useIntl();
   const router = useRouter();
   const { locale } = useContext(LanguageContext);
   const { data: movieData, error: movieError } = useSWR<MovieDetails>(
     `/api/v1/movie/${router.query.movieId}?language=${locale}`
   );
-  const { data, error, size, setSize } = useSWRInfinite<SearchResult>(
-    (pageIndex: number, previousPageData: SearchResult | null) => {
-      if (previousPageData && pageIndex + 1 > previousPageData.totalPages) {
-        return null;
-      }
-
-      return `/api/v1/movie/${router.query.movieId}/recommendations?page=${
-        pageIndex + 1
-      }&language=${locale}`;
-    },
-    {
-      initialSize: 3,
-    }
+  const {
+    isLoadingInitialData,
+    isEmpty,
+    isLoadingMore,
+    isReachingEnd,
+    titles,
+    fetchMore,
+    error,
+  } = useDiscover<MovieResult>(
+    `/api/v1/movie/${router.query.movieId}/recommendations`
   );
 
-  const isLoadingInitialData = !data && !error;
-  const isLoadingMore =
-    isLoadingInitialData ||
-    (size > 0 && data && typeof data[size - 1] === 'undefined');
-
-  const fetchMore = () => {
-    setSize(size + 1);
-  };
-
   if (error) {
-    return <div>{error}</div>;
+    return <Error statusCode={500} />;
   }
 
-  let titles = (data ?? []).reduce(
-    (a, v) => [...a, ...v.results],
-    [] as MovieResult[]
-  );
-
-  if (settings.currentSettings.hideAvailable) {
-    titles = titles.filter(
-      (i) =>
-        i.mediaInfo?.status !== MediaStatus.AVAILABLE &&
-        i.mediaInfo?.status !== MediaStatus.PARTIALLY_AVAILABLE
-    );
-  }
-
-  const isEmpty = !isLoadingInitialData && titles?.length === 0;
-  const isReachingEnd =
-    isEmpty || (data && data[data.length - 1]?.results.length < 20);
-
   return (
     <>
       <PageTitle