fix(reply modal): get mobile scroll position from hook before render

src/hooks/use-reply-modal.ts

@@ -1,9 +1,14 @@
 import { useState, useCallback } from 'react';
+import useWindowWidth from './use-window-width';
 
 const useReplyModal = () => {
   const [showReplyModal, setShowReplyModal] = useState(false);
   const [activeCid, setActiveCid] = useState<string | null>(null);
 
+  // on mobile, the position is absolute instead of fixed, so we need to calculate the top position
+  const isMobile = useWindowWidth() < 640;
+  const [scrollY, setScrollY] = useState<number>(0);
+
   const closeModal = useCallback(() => {
     setActiveCid(null);
     setShowReplyModal(false);
@@ -11,6 +16,9 @@ const useReplyModal = () => {
 
   const openReplyModal = useCallback(
     (cid: string) => {
+      if (isMobile) {
+        setScrollY(window.scrollY);
+      }
       if (activeCid && activeCid !== cid) {
         closeModal();
         setTimeout(() => {
@@ -22,10 +30,10 @@ const useReplyModal = () => {
         setShowReplyModal(true);
       }
     },
-    [activeCid, closeModal],
+    [activeCid, closeModal, isMobile],
   );
 
-  return { showReplyModal, activeCid, openReplyModal, closeModal };
+  return { activeCid, closeModal, openReplyModal, scrollY, showReplyModal };
 };
 
 export default useReplyModal;