Add "performant" recent album view

ios/JellyfinAudioPlayer.xcodeproj/project.pbxproj

@@ -45,7 +45,7 @@
 		00E356EE1AD99517003FC87E /* JellyfinAudioPlayerTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = JellyfinAudioPlayerTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		00E356F11AD99517003FC87E /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		00E356F21AD99517003FC87E /* JellyfinAudioPlayerTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = JellyfinAudioPlayerTests.m; sourceTree = "<group>"; };
-		13B07F961A680F5B00A75B9A /* JellyfinAudioPlayer.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = JellyfinAudioPlayer.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		13B07F961A680F5B00A75B9A /* Jellyfin Player.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = "Jellyfin Player.app"; sourceTree = BUILT_PRODUCTS_DIR; };
 		13B07FAF1A68108700A75B9A /* AppDelegate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = AppDelegate.h; path = JellyfinAudioPlayer/AppDelegate.h; sourceTree = "<group>"; };
 		13B07FB01A68108700A75B9A /* AppDelegate.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = AppDelegate.m; path = JellyfinAudioPlayer/AppDelegate.m; sourceTree = "<group>"; };
 		13B07FB21A68108700A75B9A /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.xib; name = Base; path = Base.lproj/LaunchScreen.xib; sourceTree = "<group>"; };
@@ -190,7 +190,7 @@
 		83CBBA001A601CBA00E9B192 /* Products */ = {
 			isa = PBXGroup;
 			children = (
-				13B07F961A680F5B00A75B9A /* JellyfinAudioPlayer.app */,
+				13B07F961A680F5B00A75B9A /* Jellyfin Player.app */,
 				00E356EE1AD99517003FC87E /* JellyfinAudioPlayerTests.xctest */,
 				2D02E47B1E0B4A5D006451C7 /* JellyfinAudioPlayer-tvOS.app */,
 				2D02E4901E0B4A5D006451C7 /* JellyfinAudioPlayer-tvOSTests.xctest */,
@@ -237,7 +237,7 @@
 			);
 			name = JellyfinAudioPlayer;
 			productName = JellyfinAudioPlayer;
-			productReference = 13B07F961A680F5B00A75B9A /* JellyfinAudioPlayer.app */;
+			productReference = 13B07F961A680F5B00A75B9A /* Jellyfin Player.app */;
 			productType = "com.apple.product-type.application";
 		};
 		2D02E47A1E0B4A5D006451C7 /* JellyfinAudioPlayer-tvOS */ = {
@@ -651,7 +651,7 @@
 					"-lc++",
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = "org.reactjs.native.example.$(PRODUCT_NAME:rfc1034identifier)";
-				PRODUCT_NAME = JellyfinAudioPlayer;
+				PRODUCT_NAME = "Jellyfin Player";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 				SWIFT_VERSION = 5.0;
 				VERSIONING_SYSTEM = "apple-generic";
@@ -674,7 +674,7 @@
 					"-lc++",
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = "org.reactjs.native.example.$(PRODUCT_NAME:rfc1034identifier)";
-				PRODUCT_NAME = JellyfinAudioPlayer;
+				PRODUCT_NAME = "Jellyfin Player";
 				SWIFT_VERSION = 5.0;
 				VERSIONING_SYSTEM = "apple-generic";
 			};

ios/JellyfinAudioPlayer.xcodeproj/xcshareddata/xcschemes/JellyfinAudioPlayer.xcscheme

@@ -15,7 +15,7 @@
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "13B07F861A680F5B00A75B9A"
-               BuildableName = "JellyfinAudioPlayer.app"
+               BuildableName = "Jellyfin Player.app"
                BlueprintName = "JellyfinAudioPlayer"
                ReferencedContainer = "container:JellyfinAudioPlayer.xcodeproj">
             </BuildableReference>
@@ -55,7 +55,7 @@
          <BuildableReference
             BuildableIdentifier = "primary"
             BlueprintIdentifier = "13B07F861A680F5B00A75B9A"
-            BuildableName = "JellyfinAudioPlayer.app"
+            BuildableName = "Jellyfin Player.app"
             BlueprintName = "JellyfinAudioPlayer"
             ReferencedContainer = "container:JellyfinAudioPlayer.xcodeproj">
          </BuildableReference>
@@ -72,7 +72,7 @@
          <BuildableReference
             BuildableIdentifier = "primary"
             BlueprintIdentifier = "13B07F861A680F5B00A75B9A"
-            BuildableName = "JellyfinAudioPlayer.app"
+            BuildableName = "Jellyfin Player.app"
             BlueprintName = "JellyfinAudioPlayer"
             ReferencedContainer = "container:JellyfinAudioPlayer.xcodeproj">
          </BuildableReference>

ios/JellyfinAudioPlayer/Info.plist

@@ -5,7 +5,7 @@
 	<key>CFBundleDevelopmentRegion</key>
 	<string>en</string>
 	<key>CFBundleDisplayName</key>
-	<string>JellyfinAudioPlayer</string>
+	<string>$(PRODUCT_NAME)</string>
 	<key>CFBundleExecutable</key>
 	<string>$(EXECUTABLE_NAME)</string>
 	<key>CFBundleIdentifier</key>

ios/Podfile.lock

@@ -325,6 +325,8 @@ PODS:
     - React
   - RNSVG (12.1.0):
     - React
+  - RNTableView (3.0.0):
+    - React
   - SDWebImage (5.8.1):
     - SDWebImage/Core (= 5.8.1)
   - SDWebImage/Core (5.8.1)
@@ -393,6 +395,7 @@ DEPENDENCIES:
   - RNReanimated (from `../node_modules/react-native-reanimated`)
   - RNScreens (from `../node_modules/react-native-screens`)
   - RNSVG (from `../node_modules/react-native-svg`)
+  - RNTableView (from `../node_modules/react-native-tableview`)
   - Yoga (from `../node_modules/react-native/ReactCommon/yoga`)
 
 SPEC REPOS:
@@ -484,6 +487,8 @@ EXTERNAL SOURCES:
     :path: "../node_modules/react-native-screens"
   RNSVG:
     :path: "../node_modules/react-native-svg"
+  RNTableView:
+    :path: "../node_modules/react-native-tableview"
   Yoga:
     :path: "../node_modules/react-native/ReactCommon/yoga"
 
@@ -514,9 +519,9 @@ SPEC CHECKSUMS:
   React-jsi: b6dc94a6a12ff98e8877287a0b7620d365201161
   React-jsiexecutor: 1540d1c01bb493ae3124ed83351b1b6a155db7da
   React-jsinspector: 512e560d0e985d0e8c479a54a4e5c147a9c83493
-  react-native-safe-area-context: e9a863c2dbbc0d42d2b12209d63fa79dfbc9662c
+  react-native-safe-area-context: e768fca90207ee68924b3d0877633f2ce9cc9d68
   react-native-track-player: ba2416753b58f3cdf9db5a07daa65876d659f925
-  react-native-webview: 938d49de66f0d5c95134f19682243cbe53294f51
+  react-native-webview: 40bbeb6d011226f34cb83f845aeb0fdf515cfc5f
   React-RCTActionSheet: f41ea8a811aac770e0cc6e0ad6b270c644ea8b7c
   React-RCTAnimation: 49ab98b1c1ff4445148b72a3d61554138565bad0
   React-RCTBlob: a332773f0ebc413a0ce85942a55b064471587a71
@@ -527,14 +532,15 @@ SPEC CHECKSUMS:
   React-RCTText: fae545b10cfdb3d247c36c56f61a94cfd6dba41d
   React-RCTVibration: 4356114dbcba4ce66991096e51a66e61eda51256
   ReactCommon: ed4e11d27609d571e7eee8b65548efc191116eb3
-  RNCAsyncStorage: db711e29e5e0500d9bd21aa0c2e397efa45302b1
+  RNCAsyncStorage: d059c3ee71738c39834a627476322a5a8cd5bf36
-  RNCMaskedView: f5c7d14d6847b7b44853f7acb6284c1da30a3459
+  RNCMaskedView: 5a8ec07677aa885546a0d98da336457e2bea557f
   RNCPicker: 1c63b084bcbcd33d159a83144543f3bda4cd1793
   RNFastImage: 35ae972d6727c84ee3f5c6897e07f84d0a3445e9
   RNGestureHandler: 8f09cd560f8d533eb36da5a6c5a843af9f056b38
   RNReanimated: b5ccb50650ba06f6e749c7c329a1bc3ae0c88b43
   RNScreens: 62211832af51e0aebcf6e8c36bcf7dd65592f244
   RNSVG: ce9d996113475209013317e48b05c21ee988d42e
+  RNTableView: e8723c30aec3b259222a12e7d05d763566286a46
   SDWebImage: e3eae2eda88578db0685a0c88597fdadd9433f05
   SDWebImageWebPCoder: 36f8f47bd9879a8aea6044765c1351120fd8e3a8
   Yoga: 3ebccbdd559724312790e7742142d062476b698e

package-lock.json

@@ -8823,6 +8823,11 @@
       "resolved": "https://registry.npmjs.org/react-native-screens/-/react-native-screens-2.8.0.tgz",
       "integrity": "sha512-fUCIQLZX+5XB0ypWX038P3zso54IFFjTsQUZJWEsjC3pp5rPItAt5SzqtJn+uVjcJaczZ+dpIuvj6IFLqkWLZQ=="
     },
+    "react-native-section-list-get-item-layout": {
+      "version": "2.2.3",
+      "resolved": "https://registry.npmjs.org/react-native-section-list-get-item-layout/-/react-native-section-list-get-item-layout-2.2.3.tgz",
+      "integrity": "sha512-fzCW5SiYP6qCZyDHebaElHonIFr8NFrZK9JDkxFLnpxMJih4d+HQ4rHyOs0Z4Gb/FjyCVbRH7RtEnjeQ0XffMg=="
+    },
     "react-native-svg": {
       "version": "12.1.0",
       "resolved": "https://registry.npmjs.org/react-native-svg/-/react-native-svg-12.1.0.tgz",
@@ -8841,6 +8846,14 @@
         "glob": "^7.1.2"
       }
     },
+    "react-native-tableview": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/react-native-tableview/-/react-native-tableview-3.0.0.tgz",
+      "integrity": "sha512-EnCNq5uKLEFsg3n7ykEvbo++sW/zUtg4cfJKYOf45s2pZoSAWvBqAjyx4G7uqhaoCLcjjDr8JiHlY62oaU7eUA==",
+      "requires": {
+        "prop-types": "^15.6.2"
+      }
+    },
     "react-native-track-player": {
       "version": "github:leinelissen/react-native-track-player#dafc8ffc0ee4bb3cdeb0fa21530c32dafa5a4dab",
       "from": "github:leinelissen/react-native-track-player"

package.json

@@ -34,8 +34,10 @@
     "react-native-reanimated": "^1.9.0",
     "react-native-safe-area-context": "^3.0.5",
     "react-native-screens": "^2.8.0",
+    "react-native-section-list-get-item-layout": "^2.2.3",
     "react-native-svg": "^12.1.0",
     "react-native-swift": "^1.2.3",
+    "react-native-tableview": "^3.0.0",
     "react-native-track-player": "github:leinelissen/react-native-track-player",
     "react-native-webview": "^10.3.1",
     "react-redux": "^7.2.0",

src/CONSTANTS.ts

@@ -1 +1,2 @@
 export const ALBUM_CACHE_AMOUNT_OF_DAYS = 7;
+export const ALPHABET_LETTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ ';

src/components/AlphabetScroller.tsx

@@ -0,0 +1,87 @@
+import React, { useCallback, useRef, useState } from 'react';
+import styled from 'styled-components/native';
+import { ALPHABET_LETTERS } from 'CONSTANTS';
+import { View, LayoutChangeEvent } from 'react-native';
+import { TouchableWithoutFeedback, PanGestureHandler, PanGestureHandlerGestureEvent, TapGestureHandler, TapGestureHandlerGestureEvent } from 'react-native-gesture-handler';
+
+interface LetterContainerProps {
+    onPress: (letter: string) => void;
+    letter: string;
+}
+
+const LetterContainer: React.FC<LetterContainerProps> = ({ children, letter, onPress }) => {
+    const handlePress = useCallback(() => {
+        onPress(letter);
+    }, [letter, onPress]);
+
+    return (
+        <TouchableWithoutFeedback onPress={handlePress}>
+            {children}
+        </TouchableWithoutFeedback>
+    );
+};
+
+const Container = styled.View`
+    position: absolute;
+    right: 5px;
+    top: 0;
+    height: 100%;
+    z-index: 10;
+    padding: 5px;
+    margin: auto 0;
+    justify-content: space-around;
+`;
+
+const Letter = styled.Text`
+    text-align: center;
+    padding: 1px 0;
+`;
+
+interface Props {
+    onSelect: (index: number) => void;
+}
+
+/**
+ * A generic component that introduces a scrolling bar on the right side of the
+ * screen with all letters of the Alphabet.
+ */
+const AlphabetScroller: React.FC<Props> = ({ onSelect }) => {
+    const [ height, setHeight ] = useState(0);
+    const [ index, setIndex ] = useState<number>();
+
+    // Handler for setting the correct height for a single alphabet item
+    const handleLayout = useCallback((event: LayoutChangeEvent) => {
+        setHeight(event.nativeEvent.layout.height);
+    }, []);
+
+    // Handler for passing on a new index when it is tapped or swiped
+    const handleGestureEvent = useCallback((event: PanGestureHandlerGestureEvent | TapGestureHandlerGestureEvent) => {
+        const newIndex = Math.floor(event.nativeEvent.y / height);
+
+        if (newIndex !== index) {
+            setIndex(newIndex);
+            onSelect(newIndex);
+        }
+    }, [height, index]);
+
+    return (
+        <Container>
+            <TapGestureHandler onHandlerStateChange={handleGestureEvent}>
+                <PanGestureHandler onGestureEvent={handleGestureEvent}>
+                    <View>
+                        {ALPHABET_LETTERS.split('').map((l, i) => (
+                            <View
+                                key={l}
+                                onLayout={i === 0 ? handleLayout : undefined}
+                            >
+                                <Letter>{l}</Letter>
+                            </View>
+                        ))}
+                    </View>
+                </PanGestureHandler>              
+            </TapGestureHandler>
+        </Container>
+    );
+};
+
+export default AlphabetScroller;

src/screens/Music/stacks/Albums.tsx

@@ -1,7 +1,7 @@
-import React, { useCallback, useEffect } from 'react';
+import React, { useCallback, useEffect, useRef, PureComponent, ReactText } from 'react';
 import { useGetImage } from 'utility/JellyfinApi';
 import { Album, NavigationProp } from '../types';
-import { Text, SafeAreaView, FlatList } from 'react-native';
+import { Text, SafeAreaView, SectionList, View } from 'react-native';
 import { useDispatch } from 'react-redux';
 import { useNavigation } from '@react-navigation/native';
 import { differenceInDays } from 'date-fns';
@@ -11,23 +11,163 @@ import { ALBUM_CACHE_AMOUNT_OF_DAYS } from 'CONSTANTS';
 import TouchableHandler from 'components/TouchableHandler';
 import ListContainer from './components/ListContainer';
 import AlbumImage, { AlbumItem } from './components/AlbumImage';
-import { useAlbumsByArtist } from 'store/music/selectors';
+import { selectAlbumsByAlphabet, SectionedId } from 'store/music/selectors';
+import AlphabetScroller from 'components/AlphabetScroller';
+import { EntityId } from '@reduxjs/toolkit';
+
+interface VirtualizedItemInfo {
+    section: SectionedId,
+    // Key of the section or combined key for section + item
+    key: string,
+    // Relative index within the section
+    index: number,
+    // True if this is the section header
+    header?: boolean,
+    leadingItem?: EntityId,
+    leadingSection?: SectionedId,
+    trailingItem?: EntityId,
+    trailingSection?: SectionedId,
+}
+
+type VirtualizedSectionList = { _subExtractor: (index: number) => VirtualizedItemInfo };
+
+function generateSection({ section }: { section: SectionedId }) {
+    return (
+        <SectionHeading label={section.label} />
+    );
+}
+
+class SectionHeading extends PureComponent<{ label: string }> {
+    render() {
+        const { label } = this.props;
+
+        return (
+            <View style={{ backgroundColor: '#f6f6f6', borderBottomColor: '#eee', borderBottomWidth: 1, height: 50, justifyContent: 'center'  }}>
+                <Text style={{ fontSize: 24, fontWeight: 'bold'}}>{label}</Text>
+            </View>
+        );
+    }
+}
+
+interface GeneratedAlbumItemProps {
+    id: ReactText;
+    imageUrl: string;
+    name: string;
+    artist: string;
+    onPress: (id: string) => void;
+}
+
+class GeneratedAlbumItem extends PureComponent<GeneratedAlbumItemProps> {
+    render() {
+        const { id, imageUrl, name, artist, onPress } = this.props;
+
+        return (
+            <TouchableHandler id={id as string} onPress={onPress}>
+                <AlbumItem>
+                    <AlbumImage source={{ uri: imageUrl }} />
+                    <Text numberOfLines={1}>{name}</Text>
+                    <Text numberOfLines={1} style={{ opacity: 0.5 }}>{artist}</Text>
+                </AlbumItem>
+            </TouchableHandler>
+        );
+    }
+}
+
+// const getItemLayout: any = sectionListGetItemLayout({
+//     getItemHeight: (rowData, sectionIndex, rowIndex) => {
+//         console.log(sectionIndex, rowIndex, rowData);
+//         if (sectionIndex === 0) { return 0; }
+//         else if (rowIndex % 2 > 0) { return 0; }
+//         return 220;
+//     },
+//     getSectionHeaderHeight: () => 50,
+//     // getSeparatorHeight: () => 1 / PixelRatio.get(),
+//     // listHeaderHeight: 0,
+// });
 
 const Albums: React.FC = () => {
     // Retrieve data from store
     const { entities: albums } = useTypedSelector((state) => state.music.albums);
-    const ids = useAlbumsByArtist();
     const isLoading = useTypedSelector((state) => state.music.albums.isLoading);
     const lastRefreshed = useTypedSelector((state) => state.music.lastRefreshed);
+    const sections = useTypedSelector(selectAlbumsByAlphabet);
     
     // Initialise helpers
     const dispatch = useDispatch();
     const navigation = useNavigation<NavigationProp>();
     const getImage = useGetImage();
+    const listRef = useRef<SectionList<EntityId>>(null);
+
+    const getItemLayout = useCallback((data: SectionedId[] | null, index: number): { offset: number, length: number, index: number } => {
+        // We must wait for the ref to become available before we can use the
+        // native item retriever in VirtualizedSectionList
+        if (!listRef.current) {
+            return { offset: 0, length: 0, index };
+        }
+
+        // Retrieve the right item info
+        // @ts-ignore
+        const wrapperListRef = (listRef.current?._wrapperListRef) as VirtualizedSectionList;
+        const info: VirtualizedItemInfo = wrapperListRef._subExtractor(index);
+        const { index: itemIndex, header, key } = info;
+        const sectionIndex = parseInt(key.split(':')[0]);
+
+        // We can then determine the "length" (=height) of this item. Header items
+        // end up with an itemIndex of -1, thus are easy to identify.
+        const length = header ? 50 : (itemIndex % 2 === 0 ? 220 : 0);
+    
+        // We'll also need to account for any unevenly-ended lists up until the
+        // current item.
+        const previousRows = data?.filter((row, i) => i < sectionIndex)
+            .reduce((sum, row) => sum + Math.ceil(row.data.length / 2), 0) || 0;
+    
+        // We must also calcuate the offset, total distance from the top of the
+        // screen. First off, we'll account for each sectionIndex that is shown up
+        // until now. This only includes the heading for the current section if the
+        // item is not the section header
+        const headingOffset = 50 * (header ? sectionIndex : sectionIndex + 1);
+        const currentRows = itemIndex > 1 ? Math.ceil((itemIndex + 1) / 2) : 0;
+        const itemOffset = 220 * (previousRows + currentRows);
+        const offset = headingOffset + itemOffset;
+    
+        // console.log(index, sectionIndex, itemIndex, previousRows, currentRows, offset);
+    
+        return { index, length, offset };
+    }, [listRef]);
 
     // Set callbacks
     const retrieveData = useCallback(() => dispatch(fetchAllAlbums()), [dispatch]);
     const selectAlbum = useCallback((id: string) => navigation.navigate('Album', { id, album: albums[id] as Album }), [navigation, albums]);
+    const selectLetter = useCallback((sectionIndex: number) => { 
+        listRef.current?.scrollToLocation({ sectionIndex, itemIndex: 0, animated: false, }); 
+    }, [listRef]);
+    const generateItem = ({ item, index, section }: { item: EntityId, index: number, section: SectionedId }) => {
+        if (index % 2 === 1) {
+            return null;
+        }
+        const nextItem = section.data[index + 1];
+
+        return (
+            <View style={{ flexDirection: 'row' }}>
+                <GeneratedAlbumItem
+                    id={item}
+                    imageUrl={getImage(item as string)}
+                    name={albums[item]?.Name || ''}
+                    artist={albums[item]?.AlbumArtist || ''}
+                    onPress={selectAlbum}
+                />
+                {albums[nextItem] && 
+                    <GeneratedAlbumItem
+                        id={nextItem}
+                        imageUrl={getImage(nextItem as string)}
+                        name={albums[nextItem]?.Name || ''}
+                        artist={albums[nextItem]?.AlbumArtist || ''}
+                        onPress={selectAlbum}
+                    />
+                }
+            </View>
+        );
+    };
 
     // Retrieve data on mount
     useEffect(() => { 
@@ -40,21 +180,17 @@ const Albums: React.FC = () => {
     return (
         <SafeAreaView>
             <ListContainer>
-                <FlatList
+                <AlphabetScroller onSelect={selectLetter} />
-                    data={ids as string[]} 
+                <SectionList
+                    sections={sections} 
                     refreshing={isLoading}
                     onRefresh={retrieveData}
-                    numColumns={2}
+                    getItemLayout={getItemLayout}
-                    keyExtractor={d => d}
+                    keyExtractor={(d) => d as string}
-                    renderItem={({ item }) => (
+                    ref={listRef}
-                        <TouchableHandler id={item} onPress={selectAlbum}>
+                    onScrollToIndexFailed={console.log}
-                            <AlbumItem>
+                    renderSectionHeader={generateSection}
-                                <AlbumImage source={{ uri: getImage(item) }} />
+                    renderItem={generateItem}
-                                <Text>{albums[item]?.Name}</Text>
-                                <Text style={{ opacity: 0.5 }}>{albums[item]?.AlbumArtist}</Text>
-                            </AlbumItem>
-                        </TouchableHandler>
-                    )}
                 />
             </ListContainer>
         </SafeAreaView>

src/screens/Music/stacks/components/AlbumImage.ts

@@ -7,6 +7,7 @@ const Screen = Dimensions.get('screen');
 export const AlbumItem = styled.View`
     width: ${Screen.width / 2 - 10}px;
     padding: 10px;
+    height: 220px;
 `;
 
 const AlbumImage = styled(FastImage)`

src/store/music/selectors.ts

@@ -1,6 +1,8 @@
-import { useTypedSelector } from 'store';
+import { useTypedSelector, AppState } from 'store';
 import { parseISO } from 'date-fns';
-import { Album } from './types';
+import { ALPHABET_LETTERS } from 'CONSTANTS';
+import { createSelector, EntityId } from '@reduxjs/toolkit';
+import { SectionListData } from 'react-native';
 
 /**
  * Retrieves a list of the n most recent albums
@@ -20,9 +22,11 @@ export function useRecentAlbums(amount: number) {
     return sorted.slice(0, amount);
 }
 
-export function useAlbumsByArtist() {
+/**
-    const albums = useTypedSelector((state) => state.music.albums.entities);
+ * Sort all albums by AlbumArtist
-    const albumIds = useTypedSelector((state) => state.music.albums.ids);
+ */
+function albumsByArtist(state: AppState['music']['albums']) {
+    const { entities: albums, ids: albumIds } = state;
 
     const sorted = [...albumIds].sort((a, b) => {
         const albumA = albums[a];
@@ -40,3 +44,36 @@ export function useAlbumsByArtist() {
 
     return sorted;
 }
+
+export const selectAlbumsByArtist = createSelector(
+    (state: AppState) => state.music.albums,
+    albumsByArtist,
+);
+
+export type SectionedId = SectionListData<EntityId>;
+
+/**
+ * Splits a set of albums into a list that is split by alphabet letters
+ */
+function splitByAlphabet(state: AppState['music']['albums']): SectionedId[] {
+    const { entities: albums } = state;
+    const albumIds = albumsByArtist(state);
+    const sections: SectionedId[] = ALPHABET_LETTERS.split('').map((l) => ({ label: l, data: [] }));
+
+    albumIds.forEach((id) => {
+        const album = albums[id];
+        const letter = album?.AlbumArtist?.toUpperCase().charAt(0);
+        const index = letter ? ALPHABET_LETTERS.indexOf(letter) : 26;
+        (sections[index >= 0 ? index : 26].data as Array<EntityId>).push(id);
+    });
+
+    return sections;
+}
+
+/**
+ * Wrap splitByAlphabet into a memoized selector
+ */
+export const selectAlbumsByAlphabet = createSelector(
+    (state: AppState) => state.music.albums,
+    splitByAlphabet,
+);