From 99767907a73a210c4a4b36d7254fa737015a75e9 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Sun, 13 Nov 2022 17:06:17 +0400
Subject: [PATCH] Spoiler: Fixes for emojis (#2132)

---
 src/components/common/MessageText.tsx     |  5 +++++
 src/components/common/spoiler/Spoiler.tsx | 25 ++++++++++++++++++-----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/src/components/common/MessageText.tsx b/src/components/common/MessageText.tsx
index 69a2ec9ee..ed583b19e 100644
--- a/src/components/common/MessageText.tsx
+++ b/src/components/common/MessageText.tsx
@@ -42,6 +42,11 @@ function MessageText({
 
   const { text, entities } = message.content.text || {};
   const withSharedCanvas = useMemo(() => {
+    const hasSpoilers = entities?.some((e) => e.type === ApiMessageEntityTypes.Spoiler);
+    if (hasSpoilers) {
+      return false;
+    }
+
     const customEmojisCount = entities?.filter((e) => e.type === ApiMessageEntityTypes.CustomEmoji).length || 0;
     return customEmojisCount >= MIN_CUSTOM_EMOJIS_FOR_SHARED_CANVAS;
   }, [entities]) || 0;
diff --git a/src/components/common/spoiler/Spoiler.tsx b/src/components/common/spoiler/Spoiler.tsx
index 255933531..9be13a3de 100644
--- a/src/components/common/spoiler/Spoiler.tsx
+++ b/src/components/common/spoiler/Spoiler.tsx
@@ -22,6 +22,7 @@ const MAX_HIDE_TIMEOUT = 60000; // 1m
 const actionsByMessageId: Map<number, {
   reveal: VoidFunction;
   conceal: VoidFunction;
+  contentLength: number;
 }[]> = new Map();
 
 const buildClassName = createClassNameBuilder('Spoiler');
@@ -35,14 +36,26 @@ const Spoiler: FC<OwnProps> = ({
 
   const [isRevealed, reveal, conceal] = useFlag();
 
+  const getContentLength = useCallback(() => {
+    if (!contentRef.current) {
+      return 0;
+    }
+
+    const textLength = contentRef.current.textContent?.length || 0;
+    const emojiCount = contentRef.current.querySelectorAll('.emoji').length;
+    // Optimization: ignore alt, assume that viewing emoji takes same time as viewing 4 characters
+    return textLength + emojiCount * 4;
+  }, []);
+
   const handleClick = useCallback((e: React.MouseEvent<HTMLDivElement, MouseEvent>) => {
     e.preventDefault();
     e.stopPropagation();
 
     actionsByMessageId.get(messageId!)?.forEach((actions) => actions.reveal());
 
-    const contentLength = contentRef.current!.innerText.length;
-    const readingMs = Math.round(contentLength / READING_SYMBOLS_PER_SECOND) * 1000;
+    const totalContentLength = actionsByMessageId.get(messageId!)
+      ?.reduce((acc, actions) => acc + actions.contentLength, 0) || 0;
+    const readingMs = Math.round(totalContentLength / READING_SYMBOLS_PER_SECOND) * 1000;
     const timeoutMs = Math.max(MIN_HIDE_TIMEOUT, Math.min(readingMs, MAX_HIDE_TIMEOUT));
 
     setTimeout(() => {
@@ -56,16 +69,18 @@ const Spoiler: FC<OwnProps> = ({
       return undefined;
     }
 
+    const contentLength = getContentLength();
+
     if (actionsByMessageId.has(messageId)) {
-      actionsByMessageId.get(messageId)!.push({ reveal, conceal });
+      actionsByMessageId.get(messageId)!.push({ reveal, conceal, contentLength });
     } else {
-      actionsByMessageId.set(messageId, [{ reveal, conceal }]);
+      actionsByMessageId.set(messageId, [{ reveal, conceal, contentLength }]);
     }
 
     return () => {
       actionsByMessageId.delete(messageId);
     };
-  }, [conceal, handleClick, isRevealed, messageId, reveal]);
+  }, [conceal, getContentLength, handleClick, isRevealed, messageId, reveal]);
 
   return (
     <span