From 1b568fc151b49372e57f6e64a45c43e2e0aaef86 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Thu, 1 Jul 2021 02:17:22 +0300
Subject: [PATCH] Save draft on app unload

---
 src/components/main/Main.tsx                  |  36 ++---
 src/components/middle/composer/Composer.tsx   |   6 +-
 .../middle/composer/MessageInput.tsx          |  28 ++--
 .../middle/composer/hooks/useDraft.ts         |  20 ++-
 src/global/cache.ts                           | 130 +++++++++++-------
 src/hooks/useBackgroundMode.ts                |  24 +++-
 src/hooks/useBeforeUnload.ts                  |   9 ++
 src/util/schedulers.ts                        |  22 +++
 8 files changed, 165 insertions(+), 110 deletions(-)
 create mode 100644 src/hooks/useBeforeUnload.ts

diff --git a/src/components/main/Main.tsx b/src/components/main/Main.tsx
index 8d7372937..ea2d15334 100644
--- a/src/components/main/Main.tsx
+++ b/src/components/main/Main.tsx
@@ -1,4 +1,6 @@
-import React, { FC, useEffect, memo } from '../../lib/teact/teact';
+import React, {
+  FC, useEffect, memo, useCallback,
+} from '../../lib/teact/teact';
 import { getGlobal, withGlobal } from '../../lib/teact/teactn';
 
 import { GlobalActions } from '../../global/types';
@@ -20,6 +22,7 @@ import { dispatchHeavyAnimationEvent } from '../../hooks/useHeavyAnimationCheck'
 import buildClassName from '../../util/buildClassName';
 import useShowTransition from '../../hooks/useShowTransition';
 import useBackgroundMode from '../../hooks/useBackgroundMode';
+import useBeforeUnload from '../../hooks/useBeforeUnload';
 
 import LeftColumn from '../left/LeftColumn';
 import MiddleColumn from '../middle/MiddleColumn';
@@ -131,26 +134,9 @@ const Main: FC<StateProps & DispatchProps> = ({
     }
   }, [animationLevel, isRightColumnShown]);
 
-  useBackgroundMode(() => {
+  const handleBlur = useCallback(() => {
     updateIsOnline(false);
-  }, () => {
-    updateIsOnline(true);
-  });
 
-  useEffect(() => {
-    function handleUnload() {
-      updateIsOnline(false);
-    }
-
-    window.addEventListener('beforeunload', handleUnload);
-
-    return () => {
-      window.removeEventListener('beforeunload', handleUnload);
-    };
-  }, [updateIsOnline]);
-
-  // Browser tab indicators
-  useBackgroundMode(() => {
     const initialUnread = selectCountNotMutedUnread(getGlobal());
     let index = 0;
 
@@ -174,7 +160,11 @@ const Main: FC<StateProps & DispatchProps> = ({
 
       index++;
     }, NOTIFICATION_INTERVAL);
-  }, () => {
+  }, [updateIsOnline]);
+
+  const handleFocus = useCallback(() => {
+    updateIsOnline(true);
+
     clearInterval(notificationInterval);
     notificationInterval = undefined;
 
@@ -183,7 +173,11 @@ const Main: FC<StateProps & DispatchProps> = ({
     }
 
     updateIcon(false);
-  });
+  }, [updateIsOnline]);
+
+  // Online status and browser tab indicators
+  useBackgroundMode(handleBlur, handleFocus);
+  useBeforeUnload(handleBlur);
 
   function stopEvent(e: React.MouseEvent<HTMLDivElement, MouseEvent>) {
     e.preventDefault();
diff --git a/src/components/middle/composer/Composer.tsx b/src/components/middle/composer/Composer.tsx
index 9b0f35eb8..89f055673 100644
--- a/src/components/middle/composer/Composer.tsx
+++ b/src/components/middle/composer/Composer.tsx
@@ -777,11 +777,11 @@ const Composer: FC<OwnProps & StateProps & DispatchProps> = ({
               activeVoiceRecording && window.innerWidth <= SCREEN_WIDTH_TO_HIDE_PLACEHOLDER ? '' : lang('Message')
             }
             shouldSetFocus={isSymbolMenuOpen}
-            shouldSupressFocus={IS_SINGLE_COLUMN_LAYOUT && isSymbolMenuOpen}
-            shouldSupressTextFormatter={isEmojiTooltipOpen || isMentionTooltipOpen}
+            shouldSuppressFocus={IS_SINGLE_COLUMN_LAYOUT && isSymbolMenuOpen}
+            shouldSuppressTextFormatter={isEmojiTooltipOpen || isMentionTooltipOpen}
             onUpdate={setHtml}
             onSend={onSend}
-            onSupressedFocus={closeSymbolMenu}
+            onSuppressedFocus={closeSymbolMenu}
           />
           {withScheduledButton && (
             <Button
diff --git a/src/components/middle/composer/MessageInput.tsx b/src/components/middle/composer/MessageInput.tsx
index d3e04bc4f..89deecc1a 100644
--- a/src/components/middle/composer/MessageInput.tsx
+++ b/src/components/middle/composer/MessageInput.tsx
@@ -36,10 +36,10 @@ type OwnProps = {
   html: string;
   placeholder: string;
   shouldSetFocus: boolean;
-  shouldSupressFocus?: boolean;
-  shouldSupressTextFormatter?: boolean;
+  shouldSuppressFocus?: boolean;
+  shouldSuppressTextFormatter?: boolean;
   onUpdate: (html: string) => void;
-  onSupressedFocus?: () => void;
+  onSuppressedFocus?: () => void;
   onSend: () => void;
 };
 
@@ -77,10 +77,10 @@ const MessageInput: FC<OwnProps & StateProps & DispatchProps> = ({
   html,
   placeholder,
   shouldSetFocus,
-  shouldSupressFocus,
-  shouldSupressTextFormatter,
+  shouldSuppressFocus,
+  shouldSuppressTextFormatter,
   onUpdate,
-  onSupressedFocus,
+  onSuppressedFocus,
   onSend,
   currentChatId,
   replyingToId,
@@ -148,7 +148,7 @@ const MessageInput: FC<OwnProps & StateProps & DispatchProps> = ({
     const selectionRange = selection.getRangeAt(0);
     const selectedText = selectionRange.toString().trim();
     if (
-      shouldSupressTextFormatter
+      shouldSuppressTextFormatter
       || !isSelectionInsideInput(selectionRange, editableInputId || EDITABLE_INPUT_ID)
       || !selectedText
       || parseEmojiOnlyString(selectedText)
@@ -344,27 +344,27 @@ const MessageInput: FC<OwnProps & StateProps & DispatchProps> = ({
   useEffect(() => {
     const input = inputRef.current!;
 
-    function supressFocus() {
+    function suppressFocus() {
       input.blur();
     }
 
-    if (shouldSupressFocus) {
-      input.addEventListener('focus', supressFocus);
+    if (shouldSuppressFocus) {
+      input.addEventListener('focus', suppressFocus);
     }
 
     return () => {
-      input.removeEventListener('focus', supressFocus);
+      input.removeEventListener('focus', suppressFocus);
     };
-  }, [shouldSupressFocus]);
+  }, [shouldSuppressFocus]);
 
   const className = buildClassName(
     'form-control custom-scroll',
     html.length > 0 && 'touched',
-    shouldSupressFocus && 'focus-disabled',
+    shouldSuppressFocus && 'focus-disabled',
   );
 
   return (
-    <div id={id} onClick={shouldSupressFocus ? onSupressedFocus : undefined} dir={lang.isRtl ? 'rtl' : undefined}>
+    <div id={id} onClick={shouldSuppressFocus ? onSuppressedFocus : undefined} dir={lang.isRtl ? 'rtl' : undefined}>
       <div
         ref={inputRef}
         id={editableInputId || EDITABLE_INPUT_ID}
diff --git a/src/components/middle/composer/hooks/useDraft.ts b/src/components/middle/composer/hooks/useDraft.ts
index 3387beca4..77e7e33ca 100644
--- a/src/components/middle/composer/hooks/useDraft.ts
+++ b/src/components/middle/composer/hooks/useDraft.ts
@@ -9,6 +9,8 @@ import { debounce } from '../../../../util/schedulers';
 import focusEditableElement from '../../../../util/focusEditableElement';
 import parseMessageInput from '../helpers/parseMessageInput';
 import getMessageTextAsHtml from '../helpers/getMessageTextAsHtml';
+import useBackgroundMode from '../../../../hooks/useBackgroundMode';
+import useBeforeUnload from '../../../../hooks/useBeforeUnload';
 
 // Used to avoid running debounced callbacks when chat changes.
 let currentChatId: number | undefined;
@@ -90,18 +92,12 @@ export default (
     }
   }, [chatId, html, prevChatId, prevHtml, prevThreadId, runDebouncedForSaveDraft, threadId, updateDraft]);
 
-  // Subscribe and handle `window.blur`
-  useEffect(() => {
-    function handleBlur() {
-      if (chatId && threadId) {
-        updateDraft(chatId, threadId);
-      }
+  const handleBlur = useCallback(() => {
+    if (chatId && threadId) {
+      updateDraft(chatId, threadId);
     }
-
-    window.addEventListener('blur', handleBlur);
-
-    return () => {
-      window.removeEventListener('blur', handleBlur);
-    };
   }, [chatId, threadId, updateDraft]);
+
+  useBackgroundMode(handleBlur);
+  useBeforeUnload(handleBlur);
 };
diff --git a/src/global/cache.ts b/src/global/cache.ts
index 7cbe17c70..6b27f17e1 100644
--- a/src/global/cache.ts
+++ b/src/global/cache.ts
@@ -5,7 +5,7 @@ import {
 import { GlobalState } from './types';
 import { MAIN_THREAD_ID } from '../api/types';
 
-import { onIdle, throttle } from '../util/schedulers';
+import { onBeforeUnload, onIdle, throttle } from '../util/schedulers';
 import {
   DEBUG,
   GLOBAL_STATE_CACHE_DISABLED,
@@ -20,11 +20,12 @@ import { INITIAL_STATE } from './initial';
 import { selectCurrentMessageList } from '../modules/selectors';
 import { hasStoredSession } from '../util/sessions';
 
-const UPDATE_THROTTLE = 1000;
+const UPDATE_THROTTLE = 5000;
 
-const updateCacheThrottled = throttle(updateCache, UPDATE_THROTTLE, false);
+const updateCacheThrottled = throttle(() => onIdle(updateCache), UPDATE_THROTTLE, false);
 
-let isAllowed = false;
+let isCaching = false;
+let unsubscribeFromBeforeUnload: NoneToVoidFunction | undefined;
 
 export function initCache() {
   if (GLOBAL_STATE_CACHE_DISABLED) {
@@ -32,29 +33,54 @@ export function initCache() {
   }
 
   addReducer('saveSession', () => {
-    isAllowed = true;
-    addCallback(updateCacheThrottled);
+    if (isCaching) {
+      return;
+    }
+
+    setupCaching();
   });
 
   addReducer('reset', () => {
-    isAllowed = false;
-    removeCallback(updateCacheThrottled);
     localStorage.removeItem(GLOBAL_STATE_CACHE_KEY);
+
+    if (!isCaching) {
+      return;
+    }
+
+    clearCaching();
   });
 }
 
 export function loadCache(initialState: GlobalState) {
-  if (!GLOBAL_STATE_CACHE_DISABLED) {
-    if (hasStoredSession(true)) {
-      isAllowed = true;
-      addCallback(updateCacheThrottled);
-      return readCache(initialState);
-    } else {
-      isAllowed = false;
-    }
+  if (GLOBAL_STATE_CACHE_DISABLED) {
+    return undefined;
   }
 
-  return undefined;
+  if (hasStoredSession(true)) {
+    setupCaching();
+
+    return readCache(initialState);
+  } else {
+    clearCaching();
+
+    return undefined;
+  }
+}
+
+function setupCaching() {
+  isCaching = true;
+  unsubscribeFromBeforeUnload = onBeforeUnload(updateCache, true);
+  window.addEventListener('blur', updateCache);
+  addCallback(updateCacheThrottled);
+}
+
+function clearCaching() {
+  isCaching = false;
+  removeCallback(updateCacheThrottled);
+  window.removeEventListener('blur', updateCache);
+  if (unsubscribeFromBeforeUnload) {
+    unsubscribeFromBeforeUnload();
+  }
 }
 
 function readCache(initialState: GlobalState) {
@@ -94,46 +120,44 @@ function readCache(initialState: GlobalState) {
 }
 
 function updateCache() {
-  onIdle(() => {
-    if (!isAllowed) {
-      return;
-    }
+  if (!isCaching) {
+    return;
+  }
 
-    const global = getGlobal();
+  const global = getGlobal();
 
-    if (global.isLoggingOut) {
-      return;
-    }
+  if (global.isLoggingOut) {
+    return;
+  }
 
-    const reducedGlobal: GlobalState = {
-      ...INITIAL_STATE,
-      ...pick(global, [
-        'authState',
-        'authPhoneNumber',
-        'authRememberMe',
-        'authNearestCountry',
-        'currentUserId',
-        'contactList',
-        'topPeers',
-        'recentEmojis',
-        'emojiKeywords',
-        'push',
-        'shouldShowContextMenuHint',
-      ]),
-      isChatInfoShown: reduceShowChatInfo(global),
-      users: reduceUsers(global),
-      chats: reduceChats(global),
-      messages: reduceMessages(global),
-      globalSearch: {
-        recentlyFoundChatIds: global.globalSearch.recentlyFoundChatIds,
-      },
-      settings: reduceSettings(global),
-      chatFolders: reduceChatFolders(global),
-    };
+  const reducedGlobal: GlobalState = {
+    ...INITIAL_STATE,
+    ...pick(global, [
+      'authState',
+      'authPhoneNumber',
+      'authRememberMe',
+      'authNearestCountry',
+      'currentUserId',
+      'contactList',
+      'topPeers',
+      'recentEmojis',
+      'emojiKeywords',
+      'push',
+      'shouldShowContextMenuHint',
+    ]),
+    isChatInfoShown: reduceShowChatInfo(global),
+    users: reduceUsers(global),
+    chats: reduceChats(global),
+    messages: reduceMessages(global),
+    globalSearch: {
+      recentlyFoundChatIds: global.globalSearch.recentlyFoundChatIds,
+    },
+    settings: reduceSettings(global),
+    chatFolders: reduceChatFolders(global),
+  };
 
-    const json = JSON.stringify(reducedGlobal);
-    localStorage.setItem(GLOBAL_STATE_CACHE_KEY, json);
-  });
+  const json = JSON.stringify(reducedGlobal);
+  localStorage.setItem(GLOBAL_STATE_CACHE_KEY, json);
 }
 
 function reduceShowChatInfo(global: GlobalState): boolean {
diff --git a/src/hooks/useBackgroundMode.ts b/src/hooks/useBackgroundMode.ts
index 80e9f8074..6a1bc3be7 100644
--- a/src/hooks/useBackgroundMode.ts
+++ b/src/hooks/useBackgroundMode.ts
@@ -1,20 +1,30 @@
 import { useEffect } from '../lib/teact/teact';
 
 export default function useBackgroundMode(
-  onBlur: AnyToVoidFunction,
-  onFocus: AnyToVoidFunction,
+  onBlur?: AnyToVoidFunction,
+  onFocus?: AnyToVoidFunction,
 ) {
   useEffect(() => {
-    if (!document.hasFocus()) {
+    if (onBlur && !document.hasFocus()) {
       onBlur();
     }
 
-    window.addEventListener('blur', onBlur);
-    window.addEventListener('focus', onFocus);
+    if (onBlur) {
+      window.addEventListener('blur', onBlur);
+    }
+
+    if (onFocus) {
+      window.addEventListener('focus', onFocus);
+    }
 
     return () => {
-      window.removeEventListener('focus', onFocus);
-      window.removeEventListener('blur', onBlur);
+      if (onFocus) {
+        window.removeEventListener('focus', onFocus);
+      }
+
+      if (onBlur) {
+        window.removeEventListener('blur', onBlur);
+      }
     };
   }, [onBlur, onFocus]);
 }
diff --git a/src/hooks/useBeforeUnload.ts b/src/hooks/useBeforeUnload.ts
new file mode 100644
index 000000000..39e1b6a5b
--- /dev/null
+++ b/src/hooks/useBeforeUnload.ts
@@ -0,0 +1,9 @@
+import { useEffect } from '../lib/teact/teact';
+
+import { onBeforeUnload } from '../util/schedulers';
+
+export default function useBeforeUnload(callback: AnyToVoidFunction) {
+  useEffect(() => {
+    return onBeforeUnload(callback);
+  }, [callback]);
+}
diff --git a/src/util/schedulers.ts b/src/util/schedulers.ts
index de6d9c8db..837938cc0 100644
--- a/src/util/schedulers.ts
+++ b/src/util/schedulers.ts
@@ -159,3 +159,25 @@ export function fastRaf(callback: NoneToVoidFunction, isPrimary = false) {
 export function fastPrimaryRaf(callback: NoneToVoidFunction) {
   fastRaf(callback, true);
 }
+
+let beforeUnloadCallbacks: NoneToVoidFunction[] | undefined;
+
+export function onBeforeUnload(callback: NoneToVoidFunction, isLast = false) {
+  if (!beforeUnloadCallbacks) {
+    beforeUnloadCallbacks = [];
+    // eslint-disable-next-line no-restricted-globals
+    self.addEventListener('beforeunload', () => {
+      beforeUnloadCallbacks!.forEach((cb) => cb());
+    });
+  }
+
+  if (isLast) {
+    beforeUnloadCallbacks.push(callback);
+  } else {
+    beforeUnloadCallbacks.unshift(callback);
+  }
+
+  return () => {
+    beforeUnloadCallbacks = beforeUnloadCallbacks!.filter((cb) => cb !== callback);
+  };
+}