fix(app): stop the inbox reshuffling unread channels as you read them (#1894)

fluxer_app/src/features/app/components/floating/UnreadChannelOrder.test.ts

@@ -1,49 +1,34 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 import {describe, expect, it} from 'vitest';
-import {mergeFrozenUnreadOrder} from './UnreadChannelOrder';
+import {selectFrozenUnreadChannels} from './UnreadChannelOrder';
 
 function ids(channels: ReadonlyArray<{id: string}>): Array<string> {
 	return channels.map((channel) => channel.id);
 }
 
-describe('mergeFrozenUnreadOrder', () => {
+describe('selectFrozenUnreadChannels', () => {
 	it('keeps channels in their frozen position while the list is open', () => {
 		const order = new Map([
 			['a', 0],
 			['b', 1],
 			['c', 2],
 		]);
-		const merged = mergeFrozenUnreadOrder(order, [{id: 'c'}, {id: 'a'}, {id: 'b'}]);
-		expect(ids(merged)).toEqual(['a', 'b', 'c']);
+		expect(ids(selectFrozenUnreadChannels(order, [{id: 'c'}, {id: 'a'}, {id: 'b'}]))).toEqual(['a', 'b', 'c']);
 	});
 
-	it('shows a channel that becomes unread after the order was frozen', () => {
+	it('hides a channel that becomes unread after the order was frozen', () => {
 		const order = new Map([['a', 0]]);
-		const merged = mergeFrozenUnreadOrder(order, [{id: 'a'}, {id: 'late'}]);
-		expect(ids(merged)).toEqual(['a', 'late']);
+		expect(ids(selectFrozenUnreadChannels(order, [{id: 'a'}, {id: 'late'}]))).toEqual(['a']);
 	});
 
-	it('appends late arrivals after existing entries rather than reshuffling', () => {
-		const order = new Map([
-			['a', 0],
-			['b', 1],
-		]);
-		const merged = mergeFrozenUnreadOrder(order, [{id: 'late'}, {id: 'b'}, {id: 'a'}]);
-		expect(ids(merged)).toEqual(['a', 'b', 'late']);
-	});
-
-	it('remembers a late arrival position once assigned', () => {
+	it('never grows the list when every live channel is new to the order', () => {
 		const order = new Map([['a', 0]]);
-		mergeFrozenUnreadOrder(order, [{id: 'a'}, {id: 'late'}]);
-		const merged = mergeFrozenUnreadOrder(order, [{id: 'late'}, {id: 'a'}]);
-		expect(ids(merged)).toEqual(['a', 'late']);
+		expect(ids(selectFrozenUnreadChannels(order, [{id: 'x'}, {id: 'y'}, {id: 'z'}]))).toEqual([]);
 	});
 
-	it('drops nothing when every channel is new', () => {
-		const order = new Map<string, number>();
-		const merged = mergeFrozenUnreadOrder(order, [{id: 'x'}, {id: 'y'}, {id: 'z'}]);
-		expect(ids(merged)).toEqual(['x', 'y', 'z']);
+	it('yields nothing for an empty order', () => {
+		expect(ids(selectFrozenUnreadChannels(new Map<string, number>(), [{id: 'x'}]))).toEqual([]);
 	});
 
 	it('does not resurrect channels that are no longer unread', () => {
@@ -51,7 +36,12 @@ describe('mergeFrozenUnreadOrder', () => {
 			['a', 0],
 			['gone', 1],
 		]);
-		const merged = mergeFrozenUnreadOrder(order, [{id: 'a'}]);
-		expect(ids(merged)).toEqual(['a']);
+		expect(ids(selectFrozenUnreadChannels(order, [{id: 'a'}]))).toEqual(['a']);
+	});
+
+	it('does not mutate the order it was given', () => {
+		const order = new Map([['a', 0]]);
+		selectFrozenUnreadChannels(order, [{id: 'a'}, {id: 'late'}]);
+		expect([...order.keys()]).toEqual(['a']);
 	});
 });

fluxer_app/src/features/app/components/floating/UnreadChannelOrder.ts

@@ -1,21 +1,62 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-function resolveUnreadOrderIndex(order: Map<string, number>, channelId: string): number {
-	const index = order.get(channelId);
-	if (index == null) {
-		return Number.POSITIVE_INFINITY;
-	}
-	return index;
+import {useEffect, useMemo, useRef, useState} from 'react';
+
+export const UNREAD_REFREEZE_COOLDOWN_MS = 10_000;
+
+export interface FrozenUnreadOrder {
+	order: Map<string, number>;
 }
 
-export function mergeFrozenUnreadOrder<T extends {id: string}>(
-	order: Map<string, number>,
-	current: ReadonlyArray<T>,
+export function selectFrozenUnreadChannels<T extends {id: string}>(
+	order: ReadonlyMap<string, number>,
+	live: ReadonlyArray<T>,
 ): Array<T> {
-	for (const channel of current) {
-		if (!order.has(channel.id)) {
-			order.set(channel.id, order.size);
-		}
+	const held: Array<{index: number; channel: T}> = [];
+	for (const channel of live) {
+		const index = order.get(channel.id);
+		if (index == null) continue;
+		held.push({index, channel});
 	}
-	return [...current].sort((a, b) => resolveUnreadOrderIndex(order, a.id) - resolveUnreadOrderIndex(order, b.id));
+	held.sort((a, b) => a.index - b.index);
+	return held.map((entry) => entry.channel);
+}
+
+export function useFrozenUnreadOrder<S extends FrozenUnreadOrder, T extends {id: string}>(
+	takeSnapshot: () => S,
+	live: ReadonlyArray<T>,
+): {snapshot: S; channels: Array<T>} {
+	const [snapshot, setSnapshot] = useState(takeSnapshot);
+	const [cooldownAttempt, setCooldownAttempt] = useState(0);
+	const snapshotTakenAtRef = useRef(Date.now());
+	const hasShownFrozenListRef = useRef(false);
+	const channels = useMemo(() => selectFrozenUnreadChannels(snapshot.order, live), [snapshot, live]);
+	useEffect(() => {
+		if (channels.length > 0) {
+			hasShownFrozenListRef.current = true;
+			return undefined;
+		}
+		const next = takeSnapshot();
+		if (next.order.size === 0) {
+			if (snapshot.order.size > 0) {
+				setSnapshot(next);
+			}
+			return undefined;
+		}
+		if (hasShownFrozenListRef.current) {
+			const heldFor = Date.now() - snapshotTakenAtRef.current;
+			if (heldFor < UNREAD_REFREEZE_COOLDOWN_MS) {
+				const timer = setTimeout(
+					() => setCooldownAttempt((attempt) => attempt + 1),
+					UNREAD_REFREEZE_COOLDOWN_MS - heldFor,
+				);
+				return () => clearTimeout(timer);
+			}
+		}
+		snapshotTakenAtRef.current = Date.now();
+		hasShownFrozenListRef.current = false;
+		setSnapshot(next);
+		return undefined;
+	}, [channels, snapshot, cooldownAttempt]);
+	return {snapshot, channels};
 }

fluxer_app/src/features/app/components/floating/UnreadChannelsContent.module.css

@@ -9,12 +9,20 @@
 	--inbox-icon-button-radius: 0.375rem;
 	--inbox-collapse-button-size: 1.375rem;
 	--inbox-collapse-button-radius: 0.375rem;
+	--inbox-sticky-header-height: 3.5rem;
 	flex: 1;
 	min-height: 0;
 	min-width: 0;
 	padding: 0 var(--inbox-scroller-padding-x) var(--inbox-scroller-padding-bottom);
 }
 
+.stickyChannelHeader {
+	position: sticky;
+	top: 0;
+	z-index: 1;
+	background-color: var(--form-surface-background);
+}
+
 .guildGroup {
 	min-width: 0;
 }
@@ -100,6 +108,8 @@
 
 .messageRow {
 	position: relative;
+	isolation: isolate;
+	scroll-margin-top: var(--inbox-sticky-header-height);
 }
 
 .messageActions {

fluxer_app/src/features/app/components/floating/UnreadChannelsContent.tsx

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 import Accessibility from '@app/features/accessibility/state/Accessibility';
-import {mergeFrozenUnreadOrder} from '@app/features/app/components/floating/UnreadChannelOrder';
+import {useFrozenUnreadOrder} from '@app/features/app/components/floating/UnreadChannelOrder';
 import styles from '@app/features/app/components/floating/UnreadChannelsContent.module.css';
 import {
 	BULK_PREVIEW_CHANNEL_BATCH_SIZE,
@@ -27,6 +27,7 @@ import {ensureMembersForMessages} from '@app/features/messaging/commands/Message
 import {InboxMessageHeader} from '@app/features/messaging/components/popouts/InboxMessageHeader';
 import {useMessageListKeyboardNavigation} from '@app/features/messaging/hooks/useMessageListKeyboardNavigation';
 import {useMessageSelectionCopyForMessages} from '@app/features/messaging/hooks/useMessageSelectionCopy';
+import {NearViewportSurfaceContext} from '@app/features/messaging/hooks/useNearViewport';
 import {Message} from '@app/features/messaging/models/MessagingMessage';
 import {ChannelMessages} from '@app/features/messaging/state/ChannelMessages';
 import {createChannelStream} from '@app/features/messaging/utils/MessageGroupingUtils';
@@ -136,6 +137,29 @@ interface ChannelPreviewData {
 const INITIAL_VISIBLE_CHANNELS = 10;
 const LOAD_MORE_CHUNK = 10;
 
+interface FrozenUnreadCounts {
+	mentionCount: number;
+	unreadCount: number;
+}
+
+interface FrozenUnreadChannels {
+	order: Map<string, number>;
+	counts: Map<string, FrozenUnreadCounts>;
+}
+
+function freezeUnreadChannels(): FrozenUnreadChannels {
+	const order = new Map<string, number>();
+	const counts = new Map<string, FrozenUnreadCounts>();
+	for (const [index, channel] of getUnreadChannels().entries()) {
+		order.set(channel.id, index);
+		counts.set(channel.id, {
+			mentionCount: ReadStates.getMentionCount(channel.id),
+			unreadCount: ReadStates.getUnreadCount(channel.id),
+		});
+	}
+	return {order, counts};
+}
+
 interface CacheEntry {
 	cacheKey: string;
 	data: ChannelPreviewData;
@@ -350,22 +374,24 @@ const UnreadChannelCard = observer(function UnreadChannelCard({
 	channel,
 	headingId,
 	previewData,
+	mentionCount,
+	unreadCount,
 }: {
 	channel: Channel;
 	headingId: string;
 	previewData: ChannelPreviewData | null;
+	mentionCount: number;
+	unreadCount: number;
 }) {
 	const {i18n} = useLingui();
 	const messageDisplayCompact = UserSettings.getMessageDisplayCompact();
 	const messageGroupSpacing = Accessibility.getMessageGroupSpacingValue(messageDisplayCompact);
-	const mentionCount = ReadStates.getMentionCount(channel.id);
 	const isCollapsed = UnreadChannels.isCollapsed(channel.id);
 	const isMuted = UserGuildSettings.isMutedAtAnyLevel(channel.guildId ?? null, channel.id);
 	const previewMessages = previewData?.messages ?? [];
 	const oldestUnreadMessageId = previewData?.oldestUnreadMessageId ?? null;
-	const totalUnreadCount = ReadStates.getUnreadCount(channel.id);
 	const hasMoreUnreadThanShown =
-		oldestUnreadMessageId != null && totalUnreadCount > 0 && totalUnreadCount > previewMessages.length;
+		oldestUnreadMessageId != null && unreadCount > 0 && unreadCount > previewMessages.length;
 	const spammerOverrideVersion = LocalUserSpamOverride.version;
 	useEffect(() => {
 		if (previewMessages.length === 0) return;
@@ -497,6 +523,7 @@ const UnreadChannelCard = observer(function UnreadChannelCard({
 				</h2>
 				<InboxMessageHeader
 					channel={channel}
+					className={styles.stickyChannelHeader}
 					onClick={handleHeaderClick}
 					mentionCount={mentionCount}
 					leftAdornment={
@@ -648,19 +675,14 @@ const UnreadChannelCard = observer(function UnreadChannelCard({
 export const UnreadChannelsContent = observer(function UnreadChannelsContent() {
 	const {i18n} = useLingui();
 	const scrollerRef = useRef<ScrollerHandle | null>(null);
+	const resolveInboxScrollSurface = useMemo(() => () => scrollerRef.current?.getViewportElement() ?? null, []);
 	const readStateVersion = ReadStates.version;
 	const settingsVersion = UserGuildSettings.version;
-	const frozenOrderRef = useRef<Map<string, number> | null>(null);
-	if (frozenOrderRef.current === null) {
-		frozenOrderRef.current = new Map(getUnreadChannels().map((channel, index) => [channel.id, index]));
-	}
-	const allUnreadChannels = useMemo(() => {
-		const order = frozenOrderRef.current;
-		if (order == null) {
-			return [];
-		}
-		return mergeFrozenUnreadOrder(order, getUnreadChannels());
-	}, [readStateVersion, settingsVersion]);
+	const liveUnreadChannels = useMemo(() => getUnreadChannels(), [readStateVersion, settingsVersion]);
+	const {snapshot: frozenUnread, channels: allUnreadChannels} = useFrozenUnreadOrder(
+		freezeUnreadChannels,
+		liveUnreadChannels,
+	);
 	const [loadedCount, setLoadedCount] = useState(INITIAL_VISIBLE_CHANNELS);
 	const visibleChannels = useMemo(() => allUnreadChannels.slice(0, loadedCount), [allUnreadChannels, loadedCount]);
 	const channelPreviews = useBulkChannelPreviews(visibleChannels);
@@ -697,19 +719,29 @@ export const UnreadChannelsContent = observer(function UnreadChannelsContent() {
 		return groups;
 	}, [visibleChannels, channelPreviews, i18n.locale]);
 	const unreadRows = useMemo(() => {
-		const rows: Array<{channel: Channel; endsGroup: boolean; groupLabel: string; key: string}> = [];
+		const rows: Array<{
+			channel: Channel;
+			endsGroup: boolean;
+			groupLabel: string;
+			key: string;
+			mentionCount: number;
+			unreadCount: number;
+		}> = [];
 		for (const group of groupedChannels) {
 			for (const [index, channel] of group.channels.entries()) {
+				const counts = frozenUnread.counts.get(channel.id);
 				rows.push({
 					channel,
 					endsGroup: index === group.channels.length - 1,
 					groupLabel: group.label,
 					key: channel.id,
+					mentionCount: counts?.mentionCount ?? 0,
+					unreadCount: counts?.unreadCount ?? 0,
 				});
 			}
 		}
 		return rows;
-	}, [groupedChannels]);
+	}, [groupedChannels, frozenUnread]);
 	const hasMore = loadedCount < allUnreadChannels.length;
 	const handleScroll = useCallback(
 		(event: React.UIEvent<HTMLDivElement>) => {
@@ -780,40 +812,44 @@ export const UnreadChannelsContent = observer(function UnreadChannelsContent() {
 		);
 	}
 	return (
-		<Scroller
-			key="unread-channels-scroller"
-			className={styles.scroller}
-			ref={scrollerRef}
-			onScroll={handleScroll}
-			onCopy={onCopySelectedMessages}
-			data-message-selection-root="true"
-			data-flx="app.floating.unread-channels-content.scroller"
-		>
-			<div className={styles.list} role="list" data-flx="app.floating.unread-channels-content.list">
-				{unreadRows.map((row, rowIndex) => (
-					<div
-						key={row.key}
-						className={clsx(styles.row, row.endsGroup && styles.rowGroupEnd)}
-						role="listitem"
-						aria-posinset={rowIndex + 1}
-						aria-setsize={unreadRows.length}
-						data-flx="app.floating.unread-channels-content.row"
-					>
-						<section
-							className={styles.guildGroup}
-							aria-label={row.groupLabel}
-							data-flx="app.floating.unread-channels-content.guild-group"
+		<NearViewportSurfaceContext.Provider value={resolveInboxScrollSurface}>
+			<Scroller
+				key="unread-channels-scroller"
+				className={styles.scroller}
+				ref={scrollerRef}
+				onScroll={handleScroll}
+				onCopy={onCopySelectedMessages}
+				data-message-selection-root="true"
+				data-flx="app.floating.unread-channels-content.scroller"
+			>
+				<div className={styles.list} role="list" data-flx="app.floating.unread-channels-content.list">
+					{unreadRows.map((row, rowIndex) => (
+						<div
+							key={row.key}
+							className={clsx(styles.row, row.endsGroup && styles.rowGroupEnd)}
+							role="listitem"
+							aria-posinset={rowIndex + 1}
+							aria-setsize={unreadRows.length}
+							data-flx="app.floating.unread-channels-content.row"
 						>
-							<UnreadChannelCard
-								channel={row.channel}
-								headingId={`inbox-unread-channel-${row.channel.id}`}
-								previewData={channelPreviews.get(row.channel.id) ?? null}
-								data-flx="app.floating.unread-channels-content.unread-channel-card"
-							/>
-						</section>
-					</div>
-				))}
-			</div>
-		</Scroller>
+							<section
+								className={styles.guildGroup}
+								aria-label={row.groupLabel}
+								data-flx="app.floating.unread-channels-content.guild-group"
+							>
+								<UnreadChannelCard
+									channel={row.channel}
+									headingId={`inbox-unread-channel-${row.channel.id}`}
+									previewData={channelPreviews.get(row.channel.id) ?? null}
+									mentionCount={row.mentionCount}
+									unreadCount={row.unreadCount}
+									data-flx="app.floating.unread-channels-content.unread-channel-card"
+								/>
+							</section>
+						</div>
+					))}
+				</div>
+			</Scroller>
+		</NearViewportSurfaceContext.Provider>
 	);
 });