Add lazy loading to discover

src/pages/discover/Discover.tsx

@@ -1,8 +1,6 @@
-import React, { useEffect, useState } from "react";
 import { Helmet } from "react-helmet-async";
 import { useTranslation } from "react-i18next";
 
-import { Loading } from "@/components/layout/Loading";
 import DiscoverContent from "@/pages/discover/discoverContent";
 
 import { SubPageLayout } from "../layouts/SubPageLayout";
@@ -11,25 +9,6 @@ import { PageTitle } from "../parts/util/PageTitle";
 export function Discover() {
   const { t } = useTranslation();
 
-  // Stupid method to "simulate" loading so the user understands this takes a white to load.
-  // TO DO: Lazy load all the media cards 💀
-
-  // State to track whether content is loading or loaded
-  const [loading, setLoading] = useState(true);
-
-  // Simulate loading media cards
-  useEffect(() => {
-    const simulateLoading = async () => {
-      // Simulate a loading time with setTimeout or fetch data here
-      await new Promise((resolve) => {
-        setTimeout(resolve, 2000);
-      }); // Simulate 2s loading time
-      setLoading(false); // After loading, set loading to false
-    };
-
-    simulateLoading();
-  }, []);
-
   return (
     <SubPageLayout>
       <Helmet>
@@ -64,20 +43,7 @@ export function Discover() {
         </p>
       </div>
 
-      {/* Conditional rendering: show loading screen or the content */}
-      {loading ? (
-        <div className="flex flex-col justify-center items-center h-64 space-y-4">
-          <Loading />
-          <p className="text-lg font-medium text-gray-400 animate-pulse mt-4">
-            Fetching the latest movies & TV shows...
-          </p>
-          <p className="text-sm text-gray-500">
-            Please wait while we load the best recommendations for you.
-          </p>
-        </div>
-      ) : (
-        <DiscoverContent />
-      )}
+      <DiscoverContent />
     </SubPageLayout>
   );
 }

src/pages/discover/components/LazyMediaCarousel.tsx

@@ -0,0 +1,78 @@
+import { useEffect, useState } from "react";
+
+import { Category, Genre, Media } from "@/pages/discover/common";
+import { useIntersectionObserver } from "@/pages/discover/hooks/useIntersectionObserver";
+import { useLazyTMDBData } from "@/pages/discover/hooks/useTMDBData";
+
+import { MediaCarousel } from "./MediaCarousel";
+
+interface LazyMediaCarouselProps {
+  category?: Category | null;
+  genre?: Genre | null;
+  mediaType: "movie" | "tv";
+  movieWidth: string;
+  isMobile: boolean;
+  carouselRefs: React.MutableRefObject<{
+    [key: string]: HTMLDivElement | null;
+  }>;
+}
+
+export function LazyMediaCarousel({
+  category,
+  genre,
+  mediaType,
+  movieWidth,
+  isMobile,
+  carouselRefs,
+}: LazyMediaCarouselProps) {
+  const [medias, setMedias] = useState<Media[]>([]);
+
+  // Use intersection observer to detect when this component is visible
+  const { targetRef, isIntersecting, hasIntersected } = useIntersectionObserver(
+    { rootMargin: "200px" }, // Load when within 200px of viewport
+    true, // Only trigger once
+  );
+
+  // Use the lazy loading hook to fetch data when visible
+  const { media, isLoading } = useLazyTMDBData(
+    genre || null,
+    category || null,
+    mediaType,
+    hasIntersected,
+  );
+
+  // Update medias when data is loaded
+  useEffect(() => {
+    if (media.length > 0) {
+      setMedias(media);
+    }
+  }, [media]);
+
+  const categoryName = category?.name || genre?.name || "";
+
+  return (
+    <div ref={targetRef as React.RefObject<HTMLDivElement>}>
+      {isIntersecting ? (
+        <MediaCarousel
+          medias={medias}
+          category={categoryName}
+          isTVShow={mediaType === "tv"}
+          movieWidth={movieWidth}
+          isMobile={isMobile}
+          carouselRefs={carouselRefs}
+        />
+      ) : (
+        <div className="relative overflow-hidden carousel-container">
+          <h2 className="ml-2 md:ml-8 mt-2 text-2xl cursor-default font-bold text-white md:text-2xl mx-auto pl-5 text-balance">
+            {categoryName} {mediaType === "tv" ? "Shows" : "Movies"}
+          </h2>
+          <div className="flex whitespace-nowrap pt-0 pb-4 overflow-auto scrollbar rounded-xl overflow-y-hidden h-[300px] animate-pulse bg-background-secondary/20">
+            <div className="w-full text-center flex items-center justify-center">
+              {isLoading ? "Loading..." : ""}
+            </div>
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}

src/pages/discover/components/LazyTabContent.tsx

@@ -0,0 +1,29 @@
+import { ReactNode, useEffect, useState } from "react";
+
+interface LazyTabContentProps {
+  isActive: boolean;
+  children: ReactNode;
+  preloadWhenInactive?: boolean;
+}
+
+export function LazyTabContent({
+  isActive,
+  children,
+  preloadWhenInactive = false,
+}: LazyTabContentProps) {
+  const [hasLoaded, setHasLoaded] = useState(false);
+
+  useEffect(() => {
+    // Load content when tab becomes active or if preload is enabled
+    if (isActive || preloadWhenInactive) {
+      setHasLoaded(true);
+    }
+  }, [isActive, preloadWhenInactive]);
+
+  // Only render children if the tab has been loaded
+  return (
+    <div style={{ display: isActive ? "block" : "none" }}>
+      {hasLoaded ? children : null}
+    </div>
+  );
+}

src/pages/discover/discoverContent.tsx

@@ -13,6 +13,8 @@ import { conf } from "@/setup/config";
 
 import "./discover.css";
 import { CategoryButtons } from "./components/CategoryButtons";
+import { LazyMediaCarousel } from "./components/LazyMediaCarousel";
+import { LazyTabContent } from "./components/LazyTabContent";
 import { MediaCarousel } from "./components/MediaCarousel";
 import { RandomMovieButton } from "./components/RandomMovieButton";
 import { ScrollToTopButton } from "./components/ScrollToTopButton";
@@ -64,13 +66,21 @@ export function DiscoverContent() {
   // Hooks
   const navigate = useNavigate();
   const { isMobile } = useIsMobile();
-  const { genreMedia: genreMovies, categoryMedia: categoryMovies } =
-    useTMDBData(genres, categories, "movie");
-  const { genreMedia: genreTVShows, categoryMedia: categoryTVShows } =
-    useTMDBData(tvGenres, tvCategories, "tv");
+  const { genreMedia: genreMovies } = useTMDBData(genres, categories, "movie");
+  // const { genreMedia: genreTVShows } = useTMDBData(
+  //   tvGenres,
+  //   tvCategories,
+  //   "tv",
+  // );
+
+  // Only load data for the active tab
+  const isMoviesTab = selectedCategory === "movies";
+  const isTVShowsTab = selectedCategory === "tvshows";
 
   // Fetch TV show genres
   useEffect(() => {
+    if (!isTVShowsTab) return;
+
     const fetchTVGenres = async () => {
       try {
         const data = await get<any>("/genre/tv/list", {
@@ -85,10 +95,12 @@ export function DiscoverContent() {
     };
 
     fetchTVGenres();
-  }, []);
+  }, [isTVShowsTab]);
 
   // Fetch Movie genres
   useEffect(() => {
+    if (!isMoviesTab) return;
+
     const fetchGenres = async () => {
       try {
         const data = await get<any>("/genre/movie/list", {
@@ -104,7 +116,7 @@ export function DiscoverContent() {
     };
 
     fetchGenres();
-  }, []);
+  }, [isMoviesTab]);
 
   useEffect(() => {
     const handleResize = () => {
@@ -182,6 +194,92 @@ export function DiscoverContent() {
     }
   };
 
+  // Render Movies content with lazy loading
+  const renderMoviesContent = () => {
+    return (
+      <>
+        {/* Provider Movies */}
+        {providerMovies.length > 0 && (
+          <MediaCarousel
+            medias={providerMovies}
+            category={selectedProvider.name}
+            isTVShow={false}
+            movieWidth={movieWidth}
+            isMobile={isMobile}
+            carouselRefs={carouselRefs}
+          />
+        )}
+
+        {/* Categories */}
+        {categories.map((category) => (
+          <LazyMediaCarousel
+            key={category.name}
+            category={category}
+            mediaType="movie"
+            movieWidth={movieWidth}
+            isMobile={isMobile}
+            carouselRefs={carouselRefs}
+          />
+        ))}
+
+        {/* Genres */}
+        {genres.map((genre) => (
+          <LazyMediaCarousel
+            key={genre.id}
+            genre={genre}
+            mediaType="movie"
+            movieWidth={movieWidth}
+            isMobile={isMobile}
+            carouselRefs={carouselRefs}
+          />
+        ))}
+      </>
+    );
+  };
+
+  // Render TV Shows content with lazy loading
+  const renderTVShowsContent = () => {
+    return (
+      <>
+        {/* Provider TV Shows */}
+        {providerTVShows.length > 0 && (
+          <MediaCarousel
+            medias={providerTVShows}
+            category={selectedProvider.name}
+            isTVShow
+            movieWidth={movieWidth}
+            isMobile={isMobile}
+            carouselRefs={carouselRefs}
+          />
+        )}
+
+        {/* Categories */}
+        {tvCategories.map((category) => (
+          <LazyMediaCarousel
+            key={category.name}
+            category={category}
+            mediaType="tv"
+            movieWidth={movieWidth}
+            isMobile={isMobile}
+            carouselRefs={carouselRefs}
+          />
+        ))}
+
+        {/* Genres */}
+        {tvGenres.map((genre) => (
+          <LazyMediaCarousel
+            key={genre.id}
+            genre={genre}
+            mediaType="tv"
+            movieWidth={movieWidth}
+            isMobile={isMobile}
+            carouselRefs={carouselRefs}
+          />
+        ))}
+      </>
+    );
+  };
+
   return (
     <div>
       {/* Random Movie Button */}
@@ -247,63 +345,18 @@ export function DiscoverContent() {
           />
         </div>
       </div>
-      {/* Content Section */}
-      <div className="w-full md:w-[90%] max-w-[2400px] mx-auto">
-        {(() => {
-          const isMovieCategory = selectedCategory === "movies";
-          const providerMedia = isMovieCategory
-            ? providerMovies
-            : providerTVShows;
-          const mediaGenres = isMovieCategory ? genres : tvGenres;
-          const mediaCategories = isMovieCategory ? categories : tvCategories;
 
-          return (
-            <>
-              {/* Media Carousels */}
-              {providerMedia.length > 0 && (
-                <MediaCarousel
-                  medias={providerMedia}
-                  category={selectedProvider.name}
-                  isTVShow={!isMovieCategory}
-                  movieWidth={movieWidth}
-                  isMobile={isMobile}
-                  carouselRefs={carouselRefs}
-                />
-              )}
-              {/* Categories and Genres */}
-              {mediaCategories.map((category) => (
-                <MediaCarousel
-                  key={category.name}
-                  medias={
-                    isMovieCategory
-                      ? categoryMovies[category.name] || []
-                      : categoryTVShows[category.name] || []
-                  }
-                  category={category.name}
-                  isTVShow={!isMovieCategory}
-                  movieWidth={movieWidth}
-                  isMobile={isMobile}
-                  carouselRefs={carouselRefs}
-                />
-              ))}
-              {mediaGenres.map((genre) => (
-                <MediaCarousel
-                  key={genre.id}
-                  medias={
-                    isMovieCategory
-                      ? genreMovies[genre.id] || []
-                      : genreTVShows[genre.id] || []
-                  }
-                  category={genre.name}
-                  isTVShow={!isMovieCategory}
-                  movieWidth={movieWidth}
-                  isMobile={isMobile}
-                  carouselRefs={carouselRefs}
-                />
-              ))}
-            </>
-          );
-        })()}
+      {/* Content Section with Lazy Loading Tabs */}
+      <div className="w-full md:w-[90%] max-w-[2400px] mx-auto">
+        {/* Movies Tab */}
+        <LazyTabContent isActive={isMoviesTab}>
+          {renderMoviesContent()}
+        </LazyTabContent>
+
+        {/* TV Shows Tab */}
+        <LazyTabContent isActive={isTVShowsTab}>
+          {renderTVShowsContent()}
+        </LazyTabContent>
       </div>
 
       <ScrollToTopButton />

src/pages/discover/hooks/useIntersectionObserver.tsx

@@ -0,0 +1,43 @@
+import { useEffect, useRef, useState } from "react";
+
+interface IntersectionObserverOptions {
+  root?: Element | null;
+  rootMargin?: string;
+  threshold?: number | number[];
+}
+
+export function useIntersectionObserver(
+  options: IntersectionObserverOptions = {},
+  onceOnly = false,
+) {
+  const [isIntersecting, setIsIntersecting] = useState(false);
+  const [hasIntersected, setHasIntersected] = useState(false);
+  const targetRef = useRef<Element | null>(null);
+
+  useEffect(() => {
+    const observer = new IntersectionObserver(([entry]) => {
+      setIsIntersecting(entry.isIntersecting);
+
+      if (entry.isIntersecting && !hasIntersected) {
+        setHasIntersected(true);
+      }
+    }, options);
+
+    const currentTarget = targetRef.current;
+    if (currentTarget) {
+      observer.observe(currentTarget);
+    }
+
+    return () => {
+      if (currentTarget) {
+        observer.unobserve(currentTarget);
+      }
+    };
+  }, [options, hasIntersected]);
+
+  // If onceOnly is true, we only care if it has ever intersected
+  // Otherwise, we care about the current intersection state
+  const shouldLoad = onceOnly ? hasIntersected : isIntersecting;
+
+  return { targetRef, isIntersecting: shouldLoad, hasIntersected };
+}

src/pages/discover/hooks/useTMDBData.tsx

@@ -10,6 +10,7 @@ export function useTMDBData(
   genres: Genre[],
   categories: Category[],
   mediaType: MediaType,
+  shouldLoad = true,
 ) {
   const [genreMedia, setGenreMedia] = useState<{
     [id: number]: Movie[] | TVShow[];
@@ -17,13 +18,15 @@ export function useTMDBData(
   const [categoryMedia, setCategoryMedia] = useState<{
     [categoryName: string]: Movie[] | TVShow[];
   }>({});
+  const [isLoading, setIsLoading] = useState(false);
 
   // Unified fetch function
   const fetchMedia = useCallback(
     async (endpoint: string, key: string, isGenre: boolean) => {
       try {
         const media: Movie[] | TVShow[] = [];
-        for (let page = 1; page <= 6; page += 1) {
+        // Reduce the number of pages to improve performance
+        for (let page = 1; page <= 2; page += 1) {
           const data = await get<any>(endpoint, {
             api_key: conf().TMDB_READ_API_KEY,
             language: "en-US",
@@ -53,7 +56,10 @@ export function useTMDBData(
 
   // Fetch media for each genre
   useEffect(() => {
+    if (!shouldLoad || genres.length === 0) return;
+
     const fetchMediaForGenres = async () => {
+      setIsLoading(true);
       const genrePromises = genres.map(async (genre) => {
         const media = await fetchMedia(
           `/discover/${mediaType}`,
@@ -63,23 +69,79 @@ export function useTMDBData(
         setGenreMedia((prev) => ({ ...prev, [genre.id]: media }));
       });
       await Promise.all(genrePromises);
+      setIsLoading(false);
     };
 
     fetchMediaForGenres();
-  }, [genres, mediaType, fetchMedia]);
+  }, [genres, mediaType, fetchMedia, shouldLoad]);
 
   // Fetch media for each category
   useEffect(() => {
+    if (!shouldLoad || categories.length === 0) return;
+
     const fetchMediaForCategories = async () => {
+      setIsLoading(true);
       const categoryPromises = categories.map(async (category) => {
         const media = await fetchMedia(category.endpoint, category.name, false);
         setCategoryMedia((prev) => ({ ...prev, [category.name]: media }));
       });
       await Promise.all(categoryPromises);
+      setIsLoading(false);
     };
 
     fetchMediaForCategories();
-  }, [categories, mediaType, fetchMedia]);
+  }, [categories, mediaType, fetchMedia, shouldLoad]);
 
-  return { genreMedia, categoryMedia };
+  return { genreMedia, categoryMedia, isLoading };
+}
+
+// Create a hook for lazy loading a specific genre or category
+export function useLazyTMDBData(
+  genre: Genre | null,
+  category: Category | null,
+  mediaType: MediaType,
+  shouldLoad = false,
+) {
+  const [media, setMedia] = useState<Movie[] | TVShow[]>([]);
+  const [isLoading, setIsLoading] = useState(false);
+
+  const fetchMedia = useCallback(
+    async (endpoint: string, key: string, isGenre: boolean) => {
+      try {
+        setIsLoading(true);
+        const mediaItems: Movie[] | TVShow[] = [];
+        // Only fetch one page for better performance
+        const data = await get<any>(endpoint, {
+          api_key: conf().TMDB_READ_API_KEY,
+          language: "en-US",
+          page: "1",
+          ...(isGenre ? { with_genres: key } : {}),
+        });
+        mediaItems.push(...data.results);
+        setMedia(mediaItems);
+        setIsLoading(false);
+        return mediaItems;
+      } catch (error) {
+        console.error(
+          `Error fetching ${mediaType} for ${isGenre ? "genre" : "category"}:`,
+          error,
+        );
+        setIsLoading(false);
+        return [];
+      }
+    },
+    [mediaType],
+  );
+
+  useEffect(() => {
+    if (!shouldLoad) return;
+
+    if (genre) {
+      fetchMedia(`/discover/${mediaType}`, genre.id.toString(), true);
+    } else if (category) {
+      fetchMedia(category.endpoint, category.name, false);
+    }
+  }, [genre, category, mediaType, fetchMedia, shouldLoad]);
+
+  return { media, isLoading };
 }