From c2b06e5cfdc0ee854267d9d92fb2d8b0b37cc7e6 Mon Sep 17 00:00:00 2001
From: Sylvain Berfini <sylvain.berfini@belledonne-communications.com>
Date: Tue, 26 Oct 2021 14:15:11 +0200
Subject: [PATCH] Added fake event to indicate first unread message & unread
 message count in chat messages list

---
 .../chat/adapters/ChatMessagesListAdapter.kt  | 61 +++++++++++++++++--
 .../chat/fragments/DetailChatRoomFragment.kt  | 28 +++++++--
 .../chat_unread_messages_list_header.xml      | 34 +++++++++++
 app/src/main/res/values/strings.xml           |  6 ++
 4 files changed, 121 insertions(+), 8 deletions(-)
 create mode 100644 app/src/main/res/layout/chat_unread_messages_list_header.xml

diff --git a/app/src/main/java/org/linphone/activities/main/chat/adapters/ChatMessagesListAdapter.kt b/app/src/main/java/org/linphone/activities/main/chat/adapters/ChatMessagesListAdapter.kt
index afc18450a..2451aff01 100644
--- a/app/src/main/java/org/linphone/activities/main/chat/adapters/ChatMessagesListAdapter.kt
+++ b/app/src/main/java/org/linphone/activities/main/chat/adapters/ChatMessagesListAdapter.kt
@@ -24,6 +24,7 @@ import android.content.ClipboardManager
 import android.content.Context
 import android.view.Gravity
 import android.view.LayoutInflater
+import android.view.View
 import android.view.ViewGroup
 import android.widget.PopupWindow
 import androidx.databinding.DataBindingUtil
@@ -43,16 +44,16 @@ import org.linphone.core.ChatMessage
 import org.linphone.core.ChatRoomCapabilities
 import org.linphone.core.Content
 import org.linphone.core.EventLog
-import org.linphone.databinding.ChatEventListCellBinding
-import org.linphone.databinding.ChatMessageListCellBinding
-import org.linphone.databinding.ChatMessageLongPressMenuBindingImpl
+import org.linphone.databinding.*
 import org.linphone.utils.AppUtils
 import org.linphone.utils.Event
+import org.linphone.utils.HeaderAdapter
 
 class ChatMessagesListAdapter(
     selectionVM: ListTopBarViewModel,
     private val viewLifecycleOwner: LifecycleOwner
-) : SelectionListAdapter<EventLogData, RecyclerView.ViewHolder>(selectionVM, ChatMessageDiffCallback()) {
+) : SelectionListAdapter<EventLogData, RecyclerView.ViewHolder>(selectionVM, ChatMessageDiffCallback()),
+    HeaderAdapter {
     companion object {
         const val MAX_TIME_TO_GROUP_MESSAGES = 60 // 1 minute
     }
@@ -97,6 +98,9 @@ class ChatMessagesListAdapter(
 
     private var contextMenuDisabled: Boolean = false
 
+    private var unreadMessagesCount: Int = 0
+    private var firstUnreadMessagePosition: Int = -1
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
         return when (viewType) {
             EventLog.Type.ConferenceChatMessage.toInt() -> createChatMessageViewHolder(parent)
@@ -133,10 +137,59 @@ class ChatMessagesListAdapter(
         return eventLog.eventLog.type.toInt()
     }
 
+    override fun onCurrentListChanged(
+        previousList: MutableList<EventLogData>,
+        currentList: MutableList<EventLogData>
+    ) {
+        // Need to wait for messages to be added before computing new first unread message position
+        firstUnreadMessagePosition = -1
+    }
+
+    override fun displayHeaderForPosition(position: Int): Boolean {
+        if (unreadMessagesCount > 0 && firstUnreadMessagePosition == -1) {
+            computeFirstUnreadMessagePosition()
+        }
+        return position == firstUnreadMessagePosition
+    }
+
+    override fun getHeaderViewForPosition(context: Context, position: Int): View {
+        val binding: ChatUnreadMessagesListHeaderBinding = DataBindingUtil.inflate(
+            LayoutInflater.from(context),
+            R.layout.chat_unread_messages_list_header, null, false
+        )
+        binding.title = AppUtils.getStringWithPlural(R.plurals.chat_room_unread_messages_event, unreadMessagesCount)
+        binding.executePendingBindings()
+        return binding.root
+    }
+
     fun disableContextMenu() {
         contextMenuDisabled = true
     }
 
+    fun setUnreadMessageCount(count: Int, forceUpdate: Boolean) {
+        // Once list has been filled once, don't show the unread message header
+        // when new messages are added to the history whilst it is visible
+        unreadMessagesCount = if (itemCount == 0 || forceUpdate) count else 0
+        firstUnreadMessagePosition = -1
+    }
+
+    private fun computeFirstUnreadMessagePosition() {
+        if (unreadMessagesCount > 0) {
+            var messageCount = 0
+            for (position in itemCount - 1 downTo 0) {
+                val eventLog = getItem(position)
+                val data = eventLog.data
+                if (data is ChatMessageData) {
+                    messageCount += 1
+                    if (messageCount == unreadMessagesCount) {
+                        firstUnreadMessagePosition = position
+                        break
+                    }
+                }
+            }
+        }
+    }
+
     inner class ChatMessageViewHolder(
         val binding: ChatMessageListCellBinding
     ) : RecyclerView.ViewHolder(binding.root) {
diff --git a/app/src/main/java/org/linphone/activities/main/chat/fragments/DetailChatRoomFragment.kt b/app/src/main/java/org/linphone/activities/main/chat/fragments/DetailChatRoomFragment.kt
index 39b9a6219..e0dd99620 100644
--- a/app/src/main/java/org/linphone/activities/main/chat/fragments/DetailChatRoomFragment.kt
+++ b/app/src/main/java/org/linphone/activities/main/chat/fragments/DetailChatRoomFragment.kt
@@ -80,7 +80,6 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
                 // But only if user hasn't initiated a scroll up in the messages history
                 if (viewModel.isUserScrollingUp.value == false) {
                     scrollToBottom()
-                    viewModel.chatRoom.markAsRead()
                 } else {
                     Log.w("[Chat Room] User has scrolled up manually in the messages history, don't scroll to the newly added message at the bottom & don't mark the chat room as read")
                 }
@@ -94,7 +93,9 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
 
     override fun onDestroyView() {
         if (_adapter != null) {
-            adapter.unregisterAdapterDataObserver(observer)
+            try {
+                adapter.unregisterAdapterDataObserver(observer)
+            } catch (ise: IllegalStateException) {}
         }
         binding.chatMessagesList.adapter = null
         super.onDestroyView()
@@ -176,6 +177,10 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
         layoutManager.stackFromEnd = true
         binding.chatMessagesList.layoutManager = layoutManager
 
+        // Displays unread messages header
+        val headerItemDecoration = RecyclerViewHeaderDecoration(requireContext(), adapter)
+        binding.chatMessagesList.addItemDecoration(headerItemDecoration)
+
         // Swipe action
         /*val swipeConfiguration = RecyclerViewSwipeConfiguration()
         swipeConfiguration.leftToRightAction = RecyclerViewSwipeConfiguration.Action(icon = R.drawable.menu_reply_default)
@@ -235,6 +240,7 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
         listViewModel.events.observe(
             viewLifecycleOwner,
             { events ->
+                adapter.setUnreadMessageCount(viewModel.chatRoom.unreadMessagesCount, viewModel.isUserScrollingUp.value == true)
                 adapter.submitList(events)
             }
         )
@@ -388,7 +394,11 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
                     }
                     val index = events.indexOf(eventLog)
                     try {
-                        binding.chatMessagesList.smoothScrollToPosition(index)
+                        if (corePreferences.enableAnimations) {
+                            binding.chatMessagesList.smoothScrollToPosition(index)
+                        } else {
+                            binding.chatMessagesList.scrollToPosition(index)
+                        }
                     } catch (iae: IllegalArgumentException) {
                         Log.e("[Chat Room] Can't scroll to position $index")
                     }
@@ -542,6 +552,7 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
             // Prevent notifications for this chat room to be displayed
             val peerAddress = viewModel.chatRoom.peerAddress.asStringUriOnly()
             coreContext.notificationsManager.currentlyDisplayedChatRoomAddress = peerAddress
+            Log.i("[Chat Room] Fragment resuming, mark chat room as read")
             viewModel.chatRoom.markAsRead()
         } else {
             Log.e("[Chat Room] Fragment resuming but viewModel lateinit property isn't initialized!")
@@ -572,6 +583,11 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
     override fun goBack() {
         if (!findNavController().popBackStack()) {
             if (sharedViewModel.isSlidingPaneSlideable.value == true) {
+                if (_adapter != null) {
+                    try {
+                        adapter.unregisterAdapterDataObserver(observer)
+                    } catch (ise: IllegalStateException) {}
+                }
                 sharedViewModel.closeSlidingPaneEvent.value = Event(true)
             } else {
                 navigateToEmptyChatRoom()
@@ -738,7 +754,11 @@ class DetailChatRoomFragment : MasterFragment<ChatRoomDetailFragmentBinding, Cha
 
     private fun smoothScrollToPosition() {
         if (_adapter != null && adapter.itemCount > 0) {
-            binding.chatMessagesList.smoothScrollToPosition(adapter.itemCount - 1)
+            if (corePreferences.enableAnimations) {
+                binding.chatMessagesList.smoothScrollToPosition(adapter.itemCount - 1)
+            } else {
+                binding.chatMessagesList.scrollToPosition(adapter.itemCount - 1)
+            }
         }
     }
 
diff --git a/app/src/main/res/layout/chat_unread_messages_list_header.xml b/app/src/main/res/layout/chat_unread_messages_list_header.xml
new file mode 100644
index 000000000..0b41e89b5
--- /dev/null
+++ b/app/src/main/res/layout/chat_unread_messages_list_header.xml
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <data>
+        <variable
+            name="title"
+            type="String" />
+    </data>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="5dp"
+        android:layout_marginBottom="5dp"
+        android:gravity="center"
+        android:background="@drawable/event_decoration_gray"
+        android:orientation="horizontal">
+
+        <TextView
+            android:text="@{title}"
+            android:textSize="13sp"
+            android:fontFamily="sans-serif"
+            android:lineSpacingExtra="0sp"
+            android:textStyle="italic"
+            android:textColor="@color/light_grey_color"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:paddingRight="5dp"
+            android:paddingLeft="5dp"
+            android:background="?attr/backgroundColor" />
+
+    </LinearLayout>
+
+</layout>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 63d22fca4..a3879da35 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -221,6 +221,12 @@
     <string name="chat_room_sending_message_hint">Message</string>
     <string name="chat_message_voice_recording_hold_to_record">Hold button to record voice message</string>
     <string name="chat_message_voice_recording_playback_low_volume">Your media volume is low, you may want to increase it</string>
+    <string name="chat_room_unread_message">%1$d unread message</string>
+    <string name="chat_room_unread_messages">%1$d unread messages</string>
+    <plurals name="chat_room_unread_messages_event">
+        <item quantity="one">@string/chat_room_unread_message</item>
+        <item quantity="other">@string/chat_room_unread_messages</item>
+    </plurals>
 
     <!-- Recordings -->
     <string name="recordings_empty_list">No recordings</string>