From 8834fe9ee7a503102a5c03b3e1fa0d3a8a7a0c1e Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Sat, 25 Sep 2021 12:36:12 +0300
Subject: [PATCH] Message List: Fix marking messages read when in background
 (#1467)

---
 src/components/middle/hooks/useMessageObservers.ts | 1 +
 src/hooks/useIntersectionObserver.ts               | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/components/middle/hooks/useMessageObservers.ts b/src/components/middle/hooks/useMessageObservers.ts
index c20f1601f..06ca65d28 100644
--- a/src/components/middle/hooks/useMessageObservers.ts
+++ b/src/components/middle/hooks/useMessageObservers.ts
@@ -31,6 +31,7 @@ export default function useMessageObservers(
   } = useIntersectionObserver({
     rootRef: containerRef,
     throttleMs: INTERSECTION_THROTTLE_FOR_READING,
+    isAutoUnfreezeDisabled: true,
   }, (entries) => {
     if (type !== 'thread') {
       return;
diff --git a/src/hooks/useIntersectionObserver.ts b/src/hooks/useIntersectionObserver.ts
index 71591dad8..9924ef96f 100644
--- a/src/hooks/useIntersectionObserver.ts
+++ b/src/hooks/useIntersectionObserver.ts
@@ -32,6 +32,7 @@ export function useIntersectionObserver({
   margin,
   threshold,
   isDisabled,
+  isAutoUnfreezeDisabled = false,
 }: {
   rootRef: RefObject<HTMLDivElement>;
   throttleMs?: number;
@@ -40,6 +41,7 @@ export function useIntersectionObserver({
   margin?: number;
   threshold?: number | number[];
   isDisabled?: boolean;
+  isAutoUnfreezeDisabled?: boolean;
 }, rootCallback?: RootCallback): Response {
   const controllerRef = useRef<IntersectionController>();
   const rootCallbackRef = useRef<RootCallback>();
@@ -65,6 +67,10 @@ export function useIntersectionObserver({
   const freeze = useCallback(() => {
     freezeFlagsRef.current++;
 
+    if (isAutoUnfreezeDisabled) {
+      return;
+    }
+
     if (autoUnfreezeTimeoutRef.current) {
       clearTimeout(autoUnfreezeTimeoutRef.current);
       autoUnfreezeTimeoutRef.current = undefined;
@@ -81,7 +87,7 @@ export function useIntersectionObserver({
       freezeFlagsRef.current = 1;
       unfreeze();
     }, AUTO_UNFREEZE_TIMEOUT);
-  }, [unfreeze]);
+  }, [isAutoUnfreezeDisabled, unfreeze]);
 
   useHeavyAnimationCheck(freeze, unfreeze);