Improve direct chat handling

We show less information in direct chats in dual chat bubble layout, as
we assume that the senders know themselves, and see the chat partner
from  the action bar at the top.

However, there are some limitations:
- A directChat might actually include more members, due to helper bots,
  multiple accounts, or misconfigurations
- Even if a direct chat has exactly two members, there might have been
  some membership changes in the past

To account for this, we do the following:
- Only enable the direct message layout if there are exactly two members
  in the room currently (in addition to the isDirect-flag being set)
- Before hiding sender information, check if the sender is actually the
  expected chat partner. If not, fallback to showing avatar and name for
  this message.

Possible improvement for the future: if we have a message in a direct
chat by a non-member, following messages by the dm chat partner might
benefit from showing member name either way.

Change-Id: Ie4a204510990301175339e60469048b06669d36b

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/helper/MessageInformationDataFactory.kt

@@ -35,6 +35,8 @@ import org.matrix.android.sdk.api.extensions.orFalse
 import org.matrix.android.sdk.api.session.Session
 import org.matrix.android.sdk.api.session.events.model.EventType
 import org.matrix.android.sdk.api.session.events.model.toModel
+import org.matrix.android.sdk.api.session.room.members.roomMemberQueryParams
+import org.matrix.android.sdk.api.session.room.model.Membership
 import org.matrix.android.sdk.api.session.room.model.ReferencesAggregatedContent
 import org.matrix.android.sdk.api.session.room.model.message.MessageVerificationRequestContent
 import org.matrix.android.sdk.api.session.room.send.SendState
@@ -76,6 +78,27 @@ class MessageInformationDataFactory @Inject constructor(private val session: Ses
         val time = dateFormatter.format(event.root.originServerTs, DateFormatKind.MESSAGE_SIMPLE)
         val e2eDecoration = getE2EDecoration(event)
 
+        var isEffectivelyDirect = false
+        var dmOtherMemberId: String? = null
+        if ((roomSummaryHolder.roomSummary?.isDirect == true) && event.root.roomId != null) {
+            val members = session.getRoom(event.root.roomId!!)
+                    ?.getRoomMembers(roomMemberQueryParams { memberships = listOf(Membership.JOIN) })
+                    ?.map { it.userId }
+                    .orEmpty()
+                    .toSet()
+            if (members.size == 2) {
+                var foundSelf = false
+                for (member in members) {
+                    if (member == session.myUserId) {
+                        foundSelf = true
+                    } else {
+                        dmOtherMemberId = member
+                    }
+                }
+                isEffectivelyDirect = foundSelf && (dmOtherMemberId != null)
+            }
+        }
+
         return MessageInformationData(
                 eventId = eventId,
                 senderId = event.root.senderId ?: "",
@@ -127,7 +150,8 @@ class MessageInformationDataFactory @Inject constructor(private val session: Ses
                 } else {
                     AnonymousReadReceipt.PROCESSING
                 },
-                isDirect = roomSummaryHolder.roomSummary?.isDirect ?: false,
+                isDirect = isEffectivelyDirect,
+                dmChatPartnerId = dmOtherMemberId,
                 e2eDecoration = e2eDecoration
         )
     }

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/item/AbsMessageItem.kt

@@ -242,7 +242,7 @@ abstract class AbsMessageItem<H : AbsMessageItem.Holder> : AbsBaseMessageItem<H>
     }
 
     override fun ignoreMessageGuideline(context: Context): Boolean {
-        return infoInBubbles(context) && (attributes.informationData.sentByMe || attributes.informationData.isDirect)
+        return infoInBubbles(context) && canHideAvatars()
     }
 
     open fun getViewStubMinimumWidth(holder: H, contentInBubble: Boolean, showInformation: Boolean): Int {
@@ -303,7 +303,8 @@ abstract class AbsMessageItem<H : AbsMessageItem.Holder> : AbsBaseMessageItem<H>
     }
 
     open fun canHideAvatars(): Boolean {
-        return attributes.informationData.sentByMe || attributes.informationData.isDirect
+        return attributes.informationData.sentByMe ||
+                (attributes.informationData.isDirect && attributes.informationData.senderId == attributes.informationData.dmChatPartnerId)
     }
 
     override fun setBubbleLayout(holder: H, bubbleStyle: String, bubbleStyleSetting: String, reverseBubble: Boolean) {

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/item/MessageInformationData.kt

@@ -44,6 +44,7 @@ data class MessageInformationData(
         val sentByMe : Boolean,
         val readReceiptAnonymous: AnonymousReadReceipt,
         val isDirect: Boolean,
+        val dmChatPartnerId: String?,
         val e2eDecoration: E2EDecoration = E2EDecoration.NONE
 ) : Parcelable {