From 9c04a2eaa525747dcea1e7d68d7feb46340b0418 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Wed, 2 Feb 2022 22:48:59 +0100
Subject: [PATCH] [Perf] Shared Media, Global Search: Improve media loading

---
 src/components/common/Media.tsx             | 33 ++++++++++++++++-----
 src/components/common/WebLink.tsx           | 10 +++++--
 src/components/left/search/FileResults.tsx  | 19 ++++++++++--
 src/components/left/search/LinkResults.tsx  | 17 +++++++++--
 src/components/left/search/MediaResults.tsx | 16 ++++++++--
 src/components/right/Profile.tsx            | 12 +++++++-
 src/modules/actions/api/localSearch.ts      | 10 ++++---
 7 files changed, 95 insertions(+), 22 deletions(-)

diff --git a/src/components/common/Media.tsx b/src/components/common/Media.tsx
index b3254f1a9..10005ad10 100644
--- a/src/components/common/Media.tsx
+++ b/src/components/common/Media.tsx
@@ -1,4 +1,4 @@
-import React, { FC, memo, useCallback } from '../../lib/teact/teact';
+import React, { FC, memo, useCallback, useRef } from '../../lib/teact/teact';
 
 import { ApiMessage } from '../../api/types';
 
@@ -12,6 +12,7 @@ import {
 import buildClassName from '../../util/buildClassName';
 import useMedia from '../../hooks/useMedia';
 import useMediaTransition from '../../hooks/useMediaTransition';
+import { ObserveFn, useIsIntersecting } from '../../hooks/useIntersectionObserver';
 
 import './Media.scss';
 
@@ -19,6 +20,7 @@ type OwnProps = {
   message: ApiMessage;
   idPrefix?: string;
   isProtected?: boolean;
+  observeIntersection?: ObserveFn;
   onClick?: (messageId: number, chatId: string) => void;
 };
 
@@ -26,26 +28,43 @@ const Media: FC<OwnProps> = ({
   message,
   idPrefix = 'shared-media',
   isProtected,
+  observeIntersection,
   onClick,
 }) => {
-  const handleClick = useCallback(() => {
-    onClick!(message.id, message.chatId);
-  }, [message.id, message.chatId, onClick]);
+  // eslint-disable-next-line no-null/no-null
+  const ref = useRef<HTMLDivElement>(null);
 
+  const isIntersecting = useIsIntersecting(ref, observeIntersection);
   const thumbDataUri = getMessageMediaThumbDataUri(message);
-  const mediaBlobUrl = useMedia(getMessageMediaHash(message, 'pictogram'));
+  const mediaBlobUrl = useMedia(getMessageMediaHash(message, 'pictogram'), !isIntersecting);
   const transitionClassNames = useMediaTransition(mediaBlobUrl);
 
   const video = getMessageVideo(message);
 
+  const handleClick = useCallback(() => {
+    onClick!(message.id, message.chatId);
+  }, [message.id, message.chatId, onClick]);
+
   return (
-    <div id={`${idPrefix}${message.id}`} className="Media scroll-item" onClick={onClick ? handleClick : undefined}>
-      <img src={thumbDataUri} alt="" draggable={!isProtected} onContextMenu={isProtected ? stopEvent : undefined} />
+    <div
+      ref={ref}
+      id={`${idPrefix}${message.id}`}
+      className="Media scroll-item"
+      onClick={onClick ? handleClick : undefined}
+    >
+      <img
+        src={thumbDataUri}
+        alt=""
+        draggable={!isProtected}
+        decoding="async"
+        onContextMenu={isProtected ? stopEvent : undefined}
+      />
       <img
         src={mediaBlobUrl}
         className={buildClassName('full-media', transitionClassNames)}
         alt=""
         draggable={!isProtected}
+        decoding="async"
         onContextMenu={isProtected ? stopEvent : undefined}
       />
       {video && <span className="video-duration">{video.isGif ? 'GIF' : formatMediaDuration(video.duration)}</span>}
diff --git a/src/components/common/WebLink.tsx b/src/components/common/WebLink.tsx
index bbb3f7524..51cbb0812 100644
--- a/src/components/common/WebLink.tsx
+++ b/src/components/common/WebLink.tsx
@@ -1,6 +1,7 @@
 import React, { FC, memo, useCallback } from '../../lib/teact/teact';
 
 import { ApiMessage, ApiWebPage } from '../../api/types';
+import { ObserveFn } from '../../hooks/useIntersectionObserver';
 
 import {
   getFirstLinkInMessage, getMessageText,
@@ -25,13 +26,16 @@ type OwnProps = {
   message: ApiMessage;
   senderTitle?: string;
   isProtected?: boolean;
+  observeIntersection?: ObserveFn;
   onMessageClick: (messageId: number, chatId: string) => void;
 };
 
-type ApiWebPageWithFormatted = ApiWebPage & { formattedDescription?: TextPart[] };
+type ApiWebPageWithFormatted =
+  ApiWebPage
+  & { formattedDescription?: TextPart[] };
 
 const WebLink: FC<OwnProps> = ({
-  message, senderTitle, isProtected, onMessageClick,
+  message, senderTitle, isProtected, observeIntersection, onMessageClick,
 }) => {
   const lang = useLang();
 
@@ -85,7 +89,7 @@ const WebLink: FC<OwnProps> = ({
       dir={lang.isRtl ? 'rtl' : undefined}
     >
       {photo && (
-        <Media message={message} isProtected={isProtected} />
+        <Media message={message} isProtected={isProtected} observeIntersection={observeIntersection} />
       )}
       <div className="content">
         <Link isRtl={lang.isRtl} className="site-title" onClick={handleMessageClick}>
diff --git a/src/components/left/search/FileResults.tsx b/src/components/left/search/FileResults.tsx
index ff751e63a..6a1fdd019 100644
--- a/src/components/left/search/FileResults.tsx
+++ b/src/components/left/search/FileResults.tsx
@@ -1,5 +1,5 @@
 import React, {
-  FC, memo, useCallback, useMemo,
+  FC, memo, useCallback, useMemo, useRef,
 } from '../../../lib/teact/teact';
 import { getDispatch, withGlobal } from '../../../lib/teact/teactn';
 
@@ -15,6 +15,7 @@ import { throttle } from '../../../util/schedulers';
 import { getMessageDocument } from '../../../modules/helpers';
 import useAsyncRendering from '../../right/hooks/useAsyncRendering';
 import useLang from '../../../hooks/useLang';
+import { useIntersectionObserver } from '../../../hooks/useIntersectionObserver';
 
 import Document from '../../common/Document';
 import InfiniteScroll from '../../ui/InfiniteScroll';
@@ -26,6 +27,8 @@ export type OwnProps = {
 };
 
 const CURRENT_TYPE = 'documents';
+const INTERSECTION_THROTTLE = 500;
+
 const runThrottled = throttle((cb) => cb(), 500, true);
 
 const FileResults: FC<OwnProps & StateProps> = ({
@@ -44,7 +47,16 @@ const FileResults: FC<OwnProps & StateProps> = ({
     focusMessage,
   } = getDispatch();
 
+  // eslint-disable-next-line no-null/no-null
+  const containerRef = useRef<HTMLDivElement>(null);
+
   const lang = useLang();
+
+  const { observe: observeIntersectionForMedia } = useIntersectionObserver({
+    rootRef: containerRef,
+    throttleMs: INTERSECTION_THROTTLE,
+  });
+
   const handleLoadMore = useCallback(({ direction }: { direction: LoadMoreDirection }) => {
     if (lastSyncTime && direction === LoadMoreDirection.Backwards) {
       runThrottled(() => {
@@ -93,8 +105,9 @@ const FileResults: FC<OwnProps & StateProps> = ({
             smaller
             sender={getSenderName(lang, message, chatsById, usersById)}
             className="scroll-item"
-            onDateClick={handleMessageFocus}
             isDownloading={activeDownloads[message.chatId]?.includes(message.id)}
+            observeIntersection={observeIntersectionForMedia}
+            onDateClick={handleMessageFocus}
           />
         </div>
       );
@@ -104,7 +117,7 @@ const FileResults: FC<OwnProps & StateProps> = ({
   const canRenderContents = useAsyncRendering([searchQuery], SLIDE_TRANSITION_DURATION) && !isLoading;
 
   return (
-    <div className="LeftSearch">
+    <div ref={containerRef} className="LeftSearch">
       <InfiniteScroll
         className="search-content documents-list custom-scroll"
         items={foundMessages}
diff --git a/src/components/left/search/LinkResults.tsx b/src/components/left/search/LinkResults.tsx
index a251952d1..633bb3560 100644
--- a/src/components/left/search/LinkResults.tsx
+++ b/src/components/left/search/LinkResults.tsx
@@ -1,5 +1,5 @@
 import React, {
-  FC, memo, useCallback, useMemo,
+  FC, memo, useCallback, useMemo, useRef,
 } from '../../../lib/teact/teact';
 import { getDispatch, withGlobal } from '../../../lib/teact/teactn';
 
@@ -13,6 +13,7 @@ import { getSenderName } from './helpers/getSenderName';
 import { throttle } from '../../../util/schedulers';
 import useAsyncRendering from '../../right/hooks/useAsyncRendering';
 import useLang from '../../../hooks/useLang';
+import { useIntersectionObserver } from '../../../hooks/useIntersectionObserver';
 
 import InfiniteScroll from '../../ui/InfiniteScroll';
 import WebLink from '../../common/WebLink';
@@ -24,6 +25,8 @@ export type OwnProps = {
 };
 
 const CURRENT_TYPE = 'links';
+const INTERSECTION_THROTTLE = 500;
+
 const runThrottled = throttle((cb) => cb(), 500, true);
 
 const LinkResults: FC<OwnProps & StateProps> = ({
@@ -42,7 +45,16 @@ const LinkResults: FC<OwnProps & StateProps> = ({
     focusMessage,
   } = getDispatch();
 
+  // eslint-disable-next-line no-null/no-null
+  const containerRef = useRef<HTMLDivElement>(null);
+
   const lang = useLang();
+
+  const { observe: observeIntersectionForMedia } = useIntersectionObserver({
+    rootRef: containerRef,
+    throttleMs: INTERSECTION_THROTTLE,
+  });
+
   const handleLoadMore = useCallback(({ direction }: { direction: LoadMoreDirection }) => {
     if (lastSyncTime && direction === LoadMoreDirection.Backwards) {
       runThrottled(() => {
@@ -91,6 +103,7 @@ const LinkResults: FC<OwnProps & StateProps> = ({
             message={message}
             senderTitle={getSenderName(lang, message, chatsById, usersById)}
             isProtected={isChatProtected || message.isProtected}
+            observeIntersection={observeIntersectionForMedia}
             onMessageClick={handleMessageFocus}
           />
         </div>
@@ -101,7 +114,7 @@ const LinkResults: FC<OwnProps & StateProps> = ({
   const canRenderContents = useAsyncRendering([searchQuery], SLIDE_TRANSITION_DURATION) && !isLoading;
 
   return (
-    <div className="LeftSearch">
+    <div ref={containerRef} className="LeftSearch">
       <InfiniteScroll
         className="search-content documents-list custom-scroll"
         items={foundMessages}
diff --git a/src/components/left/search/MediaResults.tsx b/src/components/left/search/MediaResults.tsx
index 737064cff..318c8e0fb 100644
--- a/src/components/left/search/MediaResults.tsx
+++ b/src/components/left/search/MediaResults.tsx
@@ -1,5 +1,5 @@
 import React, {
-  FC, memo, useCallback, useMemo,
+  FC, memo, useCallback, useMemo, useRef,
 } from '../../../lib/teact/teact';
 import { getDispatch, withGlobal } from '../../../lib/teact/teactn';
 
@@ -12,6 +12,7 @@ import buildClassName from '../../../util/buildClassName';
 import { throttle } from '../../../util/schedulers';
 import useLang from '../../../hooks/useLang';
 import useAsyncRendering from '../../right/hooks/useAsyncRendering';
+import { useIntersectionObserver } from '../../../hooks/useIntersectionObserver';
 
 import InfiniteScroll from '../../ui/InfiniteScroll';
 import Media from '../../common/Media';
@@ -24,6 +25,8 @@ export type OwnProps = {
 };
 
 const CURRENT_TYPE = 'media';
+const INTERSECTION_THROTTLE = 500;
+
 const runThrottled = throttle((cb) => cb(), 500, true);
 
 const MediaResults: FC<OwnProps & StateProps> = ({
@@ -40,8 +43,16 @@ const MediaResults: FC<OwnProps & StateProps> = ({
     openMediaViewer,
   } = getDispatch();
 
+  // eslint-disable-next-line no-null/no-null
+  const containerRef = useRef<HTMLDivElement>(null);
+
   const lang = useLang();
 
+  const { observe: observeIntersectionForMedia } = useIntersectionObserver({
+    rootRef: containerRef,
+    throttleMs: INTERSECTION_THROTTLE,
+  });
+
   const handleLoadMore = useCallback(({ direction }: { direction: LoadMoreDirection }) => {
     if (lastSyncTime && direction === LoadMoreDirection.Backwards) {
       runThrottled(() => {
@@ -83,6 +94,7 @@ const MediaResults: FC<OwnProps & StateProps> = ({
             idPrefix="search-media"
             message={message}
             isProtected={isChatProtected || message.isProtected}
+            observeIntersection={observeIntersectionForMedia}
             onClick={handleSelectMedia}
           />
         ))}
@@ -110,7 +122,7 @@ const MediaResults: FC<OwnProps & StateProps> = ({
   );
 
   return (
-    <div className="LeftSearch">
+    <div ref={containerRef} className="LeftSearch">
       <InfiniteScroll
         className={classNames}
         items={foundMessages}
diff --git a/src/components/right/Profile.tsx b/src/components/right/Profile.tsx
index f708fbfc3..b17c5fa7c 100644
--- a/src/components/right/Profile.tsx
+++ b/src/components/right/Profile.tsx
@@ -61,6 +61,7 @@ import DeleteMemberModal from './DeleteMemberModal';
 import GroupChatInfo from '../common/GroupChatInfo';
 
 import './Profile.scss';
+import { useIntersectionObserver } from '../../hooks/useIntersectionObserver';
 
 type OwnProps = {
   chatId: string;
@@ -104,6 +105,7 @@ const TABS = [
 ];
 
 const HIDDEN_RENDER_DELAY = 1000;
+const INTERSECTION_THROTTLE = 500;
 
 const Profile: FC<OwnProps & StateProps> = ({
   chatId,
@@ -179,6 +181,11 @@ const Profile: FC<OwnProps & StateProps> = ({
 
   const [cacheBuster, resetCacheBuster] = useCacheBuster();
 
+  const { observe: observeIntersectionForMedia } = useIntersectionObserver({
+    rootRef: containerRef,
+    throttleMs: INTERSECTION_THROTTLE,
+  });
+
   const handleTransitionStop = useCallback(() => {
     releaseTransitionFix();
     resetCacheBuster();
@@ -325,6 +332,7 @@ const Profile: FC<OwnProps & StateProps> = ({
               key={id}
               message={chatMessages[id]}
               isProtected={isChatProtected || chatMessages[id].isProtected}
+              observeIntersection={observeIntersectionForMedia}
               onClick={handleSelectMedia}
             />
           ))
@@ -336,8 +344,9 @@ const Profile: FC<OwnProps & StateProps> = ({
               withDate
               smaller
               className="scroll-item"
-              onDateClick={handleMessageFocus}
               isDownloading={activeDownloadIds.includes(id)}
+              observeIntersection={observeIntersectionForMedia}
+              onDateClick={handleMessageFocus}
             />
           ))
         ) : resultType === 'links' ? (
@@ -346,6 +355,7 @@ const Profile: FC<OwnProps & StateProps> = ({
               key={id}
               message={chatMessages[id]}
               isProtected={isChatProtected || chatMessages[id].isProtected}
+              observeIntersection={observeIntersectionForMedia}
               onMessageClick={handleMessageFocus}
             />
           ))
diff --git a/src/modules/actions/api/localSearch.ts b/src/modules/actions/api/localSearch.ts
index 939a6bb86..e2e6d50cc 100644
--- a/src/modules/actions/api/localSearch.ts
+++ b/src/modules/actions/api/localSearch.ts
@@ -126,11 +126,12 @@ async function searchSharedMedia(
   chatOrUser: ApiChat | ApiUser,
   type: SharedMediaType,
   offsetId?: number,
+  isBudgetPreload = false,
 ) {
   const result = await callApi('searchMessagesLocal', {
     chatOrUser,
     type,
-    limit: SHARED_MEDIA_SLICE,
+    limit: SHARED_MEDIA_SLICE * 2,
     offsetId,
   });
 
@@ -156,11 +157,12 @@ async function searchSharedMedia(
   global = addUsers(global, buildCollectionByKey(users, 'id'));
   global = updateLocalMediaSearchResults(global, chatOrUser.id, type, newFoundIds, totalCount, nextOffsetId);
   setGlobal(global);
+
+  if (!isBudgetPreload) {
+    searchSharedMedia(chatOrUser, type, nextOffsetId, true);
+  }
 }
 
-/**
- * @param timestamp start of target date in seconds
- */
 async function searchMessagesByDate(chat: ApiChat, timestamp: number) {
   const messageId = await callApi('findFirstMessageIdAfterDate', {
     chat,