fix(fc): prevent jumping back to unread separator

Signed-off-by: Brandon McAnsh <git@bmcreations.dev>

Author: bmc08gt

flipchatApp/src/main/kotlin/xyz/flipchat/app/features/chat/conversation/ConversationMessages.kt

@@ -1,7 +1,10 @@
 package xyz.flipchat.app.features.chat.conversation
 
+import androidx.compose.animation.core.animateFloatAsState
+import androidx.compose.animation.core.tween
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.rememberLazyListState
@@ -135,10 +138,16 @@ internal fun ConversationMessages(
             }
         )
 
+        val animatedAlpha by animateFloatAsState(
+            targetValue = if (lazyListState.canScrollBackward) 1f else 0f,
+            animationSpec = tween(durationMillis = 300),
+            label = "alpha of jump-to-bottom"
+        )
+
         Surface(
             modifier = Modifier
                 .graphicsLayer {
-                    alpha = if (lazyListState.canScrollBackward) 1f else 0f
+                    alpha = animatedAlpha
                 }
                 .padding(
                     end = CodeTheme.dimens.inset,

flipchatApp/src/main/kotlin/xyz/flipchat/app/features/chat/conversation/ConversationViewModel.kt

@@ -720,7 +720,6 @@ class ConversationViewModel @Inject constructor(
                     messageControls = MessageControls(
                         actions = buildMessageActions(message, member, contents, enableReply),
                     ),
-                    key = message.id.uuid.toString()
                 )
             }
         }

ui/components/src/main/kotlin/com/getcode/ui/components/chat/MessageList.kt

@@ -12,6 +12,7 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Modifier
@@ -33,6 +34,7 @@ import com.getcode.util.formatDateRelatively
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.filter
+import kotlinx.coroutines.flow.filterNot
 
 sealed interface MessageListEvent {
     data class AdvancePointer(val messageId: ID) : MessageListEvent
@@ -66,7 +68,7 @@ fun MessageList(
     },
     dispatch: (MessageListEvent) -> Unit = { },
 ) {
-    var hasSetAtUnread by remember { mutableStateOf(false) }
+    var hasSetAtUnread by rememberSaveable(key = "0") { mutableStateOf(false) }
 
     HandleMessageReads(listState, messages, hasSetAtUnread) {
         dispatch(MessageListEvent.AdvancePointer(it))
@@ -252,23 +254,21 @@ private fun HandleStartAtUnread(
     hasSetAtUnread: Boolean,
     onHandled: () -> Unit,
 ) {
-    val density = LocalDensity.current
+    // Flag to ensure scroll logic runs only once
+    var hasScrolledToUnread by rememberSaveable { mutableStateOf(false) }
+
     LaunchedEffect(listState, messages) {
         snapshotFlow { messages.loadState }
+            .filterNot { hasScrolledToUnread }
             .collect { loadState ->
                 if (loadState.refresh is LoadState.NotLoading && messages.itemCount > 0) {
                     val separatorIndex = messages.itemSnapshotList
                         .indexOfFirst { it is ChatItem.UnreadSeparator }
 
-                    if (separatorIndex >= 0 && !hasSetAtUnread) {
-                        // Calculate the center offset
-                        val centerOffset = with(density) {
-                            val viewportHeight = listState.layoutInfo.viewportSize.height.toDp()
-                            viewportHeight.roundToPx() / 2
-                        }
-
+                    if (separatorIndex > 0 && !hasSetAtUnread) {
                         onHandled()
-                        listState.scrollToItem(separatorIndex, scrollOffset = -centerOffset)
+                        hasScrolledToUnread = true
+                        listState.scrollToItem(separatorIndex - 1)
                     } else {
                         onHandled()
                     }

ui/components/src/main/kotlin/com/getcode/ui/components/chat/utils/ChatItem.kt

@@ -6,6 +6,7 @@ import com.getcode.model.chat.ChatMessage
 import com.getcode.model.chat.MessageContent
 import com.getcode.model.chat.MessageStatus
 import com.getcode.model.chat.Sender
+import com.getcode.model.uuid
 import com.getcode.ui.components.chat.messagecontents.MessageControls
 import com.getcode.util.formatDateRelatively
 import kotlinx.datetime.Instant
@@ -26,7 +27,6 @@ data class ReplyMessageAnchor(
 sealed class ChatItem(open val key: Any) {
     @Stable
     data class Message(
-        val id: String = UUID.randomUUID().toString(),
         val chatMessageId: ID,
         val message: MessageContent,
         val sender: Sender,
@@ -40,8 +40,7 @@ sealed class ChatItem(open val key: Any) {
         val enableMarkup: Boolean = false,
         val enableReply: Boolean = false,
         val originalMessage: ReplyMessageAnchor? = null,
-        override val key: Any = id
-    ) : ChatItem(key) {
+    ) : ChatItem(chatMessageId.uuid!!) {
         val relativeDate: String = date.formatDateRelatively()
     }