Feature/automatically load more pages until scrollbar is visible (#667)

* Rename "grifRed" to "gridWrapperRef"

* Automatically fetch more pages until scrollbar is visible

src/components/MangaGrid.tsx

@@ -6,7 +6,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-import React, { useEffect, useLayoutEffect, useMemo, useRef, useState } from 'react';
+import React, { ForwardedRef, forwardRef, useEffect, useLayoutEffect, useMemo, useRef, useState } from 'react';
 import Grid, { GridTypeMap } from '@mui/material/Grid';
 import { Box, Typography } from '@mui/material';
 import { GridItemProps, GridStateSnapshot, VirtuosoGrid } from 'react-virtuoso';
@@ -73,7 +73,9 @@ type DefaultGridProps = Pick<MangaCardProps, 'mode'> & {
     handleSelection?: SelectableCollectionReturnType<TManga['id']>['handleSelection'];
 };
 
-const HorizontalGrid = ({
+const HorizontalGrid = forwardRef(
+    (
+        {
             isLoading,
             mangas,
             inLibraryIndicator,
@@ -83,8 +85,11 @@ const HorizontalGrid = ({
             selectedMangaIds,
             handleSelection,
             mode,
-}: DefaultGridProps) => (
+        }: DefaultGridProps,
+        ref: ForwardedRef<HTMLDivElement | null>,
+    ) => (
         <Grid
+            ref={ref}
             container
             spacing={1}
             style={{
@@ -114,9 +119,12 @@ const HorizontalGrid = ({
                 ))
             )}
         </Grid>
+    ),
 );
 
-const VerticalGrid = ({
+const VerticalGrid = forwardRef(
+    (
+        {
             isLoading,
             mangas,
             inLibraryIndicator,
@@ -131,7 +139,9 @@ const VerticalGrid = ({
         }: DefaultGridProps & {
             hasNextPage: boolean;
             loadMore: () => void;
-}) => {
+        },
+        ref: ForwardedRef<HTMLDivElement | null>,
+    ) => {
         const location = useLocation<{ snapshot?: GridStateSnapshot }>();
         const navigate = useNavigate();
         const { snapshot } = location.state ?? {};
@@ -157,6 +167,7 @@ const VerticalGrid = ({
 
         return (
             <>
+                <Box ref={ref}>
                     <VirtuosoGrid
                         useWindowScroll
                         overscan={window.innerHeight * 0.25}
@@ -180,6 +191,7 @@ const VerticalGrid = ({
                             )
                         }
                     />
+                </Box>
                 {/* render div to prevent UI jumping around when showing/hiding loading placeholder */
                 /* eslint-disable-next-line no-nested-ternary */}
                 {isSelectModeActive && gridLayout === GridLayout.List ? (
@@ -192,7 +204,8 @@ const VerticalGrid = ({
                 ) : null}
             </>
         );
-};
+    },
+);
 
 export interface IMangaGridProps extends Omit<DefaultGridProps, 'GridItemContainer'> {
     message?: string;
@@ -221,9 +234,11 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
         mode,
     } = props;
 
+    const gridRef = useRef<HTMLDivElement>(null);
+
     const [dimensions, setDimensions] = useState(document.documentElement.offsetWidth);
     const [gridItemWidth] = useLocalStorage<number>('ItemWidth', 300);
-    const gridRef = useRef<HTMLDivElement>(null);
+    const gridWrapperRef = useRef<HTMLDivElement>(null);
     const GridItemContainer = useMemo(
         () => GridItemContainerWithDimension(dimensions, gridItemWidth, gridLayout),
         [dimensions, gridItemWidth, gridLayout],
@@ -231,7 +246,7 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
 
     const updateGridWidth = () => {
         const getDimensions = () => {
-            const gridWidth = gridRef.current?.offsetWidth;
+            const gridWidth = gridWrapperRef.current?.offsetWidth;
 
             if (!gridWidth) {
                 return document.documentElement.offsetWidth;
@@ -258,6 +273,36 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
         return () => window.removeEventListener('resize', onResize);
     }, []);
 
+    useEffect(() => {
+        if (!gridRef.current) {
+            return () => {};
+        }
+
+        if (gridRef.current.offsetHeight > document.documentElement.clientHeight) {
+            return () => {};
+        }
+
+        const resizeObserver = new ResizeObserver(() => {
+            const gridHeight = gridRef.current!.offsetHeight;
+            const isScrollbarVisible = gridHeight > document.documentElement.clientHeight;
+
+            if (!gridHeight) {
+                return;
+            }
+
+            if (isScrollbarVisible) {
+                resizeObserver.disconnect();
+                return;
+            }
+
+            loadMore();
+            resizeObserver.disconnect();
+        });
+        resizeObserver.observe(gridRef.current);
+
+        return () => resizeObserver.disconnect();
+    }, [loadMore]);
+
     const hasNoItems = !isLoading && mangas.length === 0;
     if (hasNoItems) {
         if (noFaces) {
@@ -278,7 +323,7 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
 
     return (
         <div
-            ref={gridRef}
+            ref={gridWrapperRef}
             style={{
                 overflow: 'hidden',
                 paddingBottom: '13px',
@@ -286,6 +331,7 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
         >
             {horizontal ? (
                 <HorizontalGrid
+                    ref={gridRef}
                     isLoading={isLoading}
                     mangas={mangas}
                     inLibraryIndicator={inLibraryIndicator}
@@ -298,6 +344,7 @@ export const MangaGrid: React.FC<IMangaGridProps> = (props) => {
                 />
             ) : (
                 <VerticalGrid
+                    ref={gridRef}
                     isLoading={isLoading}
                     mangas={mangas}
                     inLibraryIndicator={inLibraryIndicator}

src/screens/SourceMangas.tsx

@@ -13,7 +13,7 @@ import SettingsIcon from '@mui/icons-material/Settings';
 import { useQueryParam, StringParam } from 'use-query-params';
 import { useTranslation } from 'react-i18next';
 import Link from '@mui/material/Link';
-import { Box, Button, styled, useTheme, useMediaQuery, Tooltip } from '@mui/material';
+import { Box, Button, styled, Tooltip } from '@mui/material';
 import FavoriteIcon from '@mui/icons-material/Favorite';
 import NewReleasesIcon from '@mui/icons-material/NewReleases';
 import FilterListIcon from '@mui/icons-material/FilterList';
@@ -194,9 +194,6 @@ export function SourceMangas() {
     const { t } = useTranslation();
     const { setTitle, setAction } = useContext(NavBarContext);
 
-    const theme = useTheme();
-    const isLargeScreen = useMediaQuery(theme.breakpoints.up('sm'));
-
     const { sourceId } = useParams<{ sourceId: string }>();
 
     const navigate = useNavigate();
@@ -232,7 +229,7 @@ export function SourceMangas() {
         contentType,
         searchTerm,
         filtersToApply,
-        isLargeScreen ? 2 : 1,
+        1,
     );
     const mangas = data?.fetchSourceManga.mangas ?? [];
     const hasNextPage = data?.fetchSourceManga.hasNextPage ?? false;