From 656c10976b2ca53dbc40306ab2495ace1ed94d24 Mon Sep 17 00:00:00 2001
From: Stanislav Dmitrenko <7953703+avently@users.noreply.github.com>
Date: Sun, 16 Oct 2022 14:41:01 +0300
Subject: [PATCH] android: Fix autoscroll to bottom when going from group to
 direct (#1209)

* android: Fix autoscroll to bottom when going from group to direct
- and makes scrolling smoother because of -1 number of recompose

* Rename
---
 .../chat/simplex/app/views/chat/ChatView.kt   | 27 +++++++++++--------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/apps/android/app/src/main/java/chat/simplex/app/views/chat/ChatView.kt b/apps/android/app/src/main/java/chat/simplex/app/views/chat/ChatView.kt
index 2849218d8e..1fc14e1027 100644
--- a/apps/android/app/src/main/java/chat/simplex/app/views/chat/ChatView.kt
+++ b/apps/android/app/src/main/java/chat/simplex/app/views/chat/ChatView.kt
@@ -48,7 +48,6 @@ import kotlinx.coroutines.flow.*
 import kotlinx.datetime.Clock
 import java.io.File
 import kotlin.math.sign
-import kotlin.math.roundToInt
 
 @Composable
 fun ChatView(chatModel: ChatModel) {
@@ -447,16 +446,7 @@ fun BoxWithConstraintsScope.ChatItemsList(
   val scope = rememberCoroutineScope()
   val uriHandler = LocalUriHandler.current
   val cxt = LocalContext.current
-  // Helps to scroll to bottom after moving from Group to Direct chat
-  // and prevents scrolling to bottom on orientation change
-  var shouldAutoScroll by rememberSaveable { mutableStateOf(true) }
-  LaunchedEffect(chat.chatInfo.apiId, chat.chatInfo.chatType, shouldAutoScroll) {
-    if (shouldAutoScroll && listState.firstVisibleItemIndex != 0) {
-      scope.launch { listState.scrollToItem(0) }
-    }
-    // Don't autoscroll next time until it will be needed
-    shouldAutoScroll = false
-  }
+  ScrollToBottom(chat.id, listState)
   var prevSearchEmptiness by rememberSaveable { mutableStateOf(searchValue.value.isEmpty()) }
   // Scroll to bottom when search value changes from something to nothing and back
   LaunchedEffect(searchValue.value.isEmpty()) {
@@ -578,6 +568,21 @@ fun BoxWithConstraintsScope.ChatItemsList(
   FloatingButtons(chatItems, unreadCount, chat.chatStats.minUnreadItemId, searchValue, markRead, setFloatingButton, listState)
 }
 
+@Composable
+private fun ScrollToBottom(chatId: ChatId, listState: LazyListState) {
+  val scope = rememberCoroutineScope()
+  // Helps to scroll to bottom after moving from Group to Direct chat
+  // and prevents scrolling to bottom on orientation change
+  var shouldAutoScroll by rememberSaveable { mutableStateOf(true to chatId) }
+  LaunchedEffect(chatId, shouldAutoScroll) {
+    if ((shouldAutoScroll.first || shouldAutoScroll.second != chatId) && listState.firstVisibleItemIndex != 0) {
+      scope.launch { listState.scrollToItem(0) }
+    }
+    // Don't autoscroll next time until it will be needed
+    shouldAutoScroll = false to chatId
+  }
+}
+
 @Composable
 fun BoxWithConstraintsScope.FloatingButtons(
   chatItems: List<ChatItem>,