Unify the way we decide whether a room is a DM or a group room (#3100)

* Add centralised 'room is DM' check

Also add extension functions for `MatrixRoom` and `MatrixRoomInfo`.

* Use the centralised method and extension functions through the app, including:

- Room list.
- Room details screen.
- Invites.
- Notifications.

Replace most `isDirect` usages with `isDm`.

* Update screenshots

---------

Co-authored-by: ElementBot <benoitm+elementbot@element.io>

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/notification/NotificationData.kt

@@ -33,6 +33,7 @@ data class NotificationData(
     val roomAvatarUrl: String?,
     val roomDisplayName: String?,
     val isDirect: Boolean,
+    val isDm: Boolean,
     val isEncrypted: Boolean,
     val isNoisy: Boolean,
     val timestamp: Long,

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/MatrixRoom.kt

@@ -57,9 +57,6 @@ interface MatrixRoom : Closeable {
     val activeMemberCount: Long
     val joinedMemberCount: Long
 
-    /** Whether the room is a direct message. */
-    val isDm: Boolean get() = isDirect && isOneToOne
-
     val roomInfoFlow: Flow<MatrixRoomInfo>
     val roomTypingMembersFlow: Flow<List<UserId>>
 

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/RoomIsDmCheck.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2024 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.room
+
+/**
+ * Returns whether the room with the provided info is a DM.
+ * A DM is a room with at most 2 active members (one of them may have left).
+ *
+ * @param isDirect true if the room is direct
+ * @param activeMembersCount the number of active members in the room (joined or invited)
+ */
+fun isDm(isDirect: Boolean, activeMembersCount: Int): Boolean {
+    return isDirect && activeMembersCount <= 2
+}
+
+/**
+ * Returns whether the [MatrixRoom] is a DM.
+ */
+val MatrixRoom.isDm get() = isDm(isDirect, activeMemberCount.toInt())
+
+/**
+ * Returns whether the [MatrixRoomInfo] is from a DM.
+ */
+val MatrixRoomInfo.isDm get() = isDm(isDirect, activeMembersCount.toInt())

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/recent/RecentDirectRoom.kt

@@ -21,6 +21,7 @@ import io.element.android.libraries.matrix.api.core.RoomId
 import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.room.CurrentUserMembership
 import io.element.android.libraries.matrix.api.room.MatrixRoom
+import io.element.android.libraries.matrix.api.room.isDm
 import io.element.android.libraries.matrix.api.room.toMatrixUser
 import io.element.android.libraries.matrix.api.user.MatrixUser
 import kotlinx.coroutines.flow.first

libraries/matrix/api/src/test/kotlin/io/element/android/libraries/matrix/api/room/RoomIsDmCheckTest.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2024 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.room
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+
+class RoomIsDmCheckTest {
+    @Test
+    fun `a room is a DM only if it has at most 2 members and is direct`() {
+        val isDirect = true
+        val activeMembersCount = 2
+
+        val isDm = isDm(isDirect, activeMembersCount)
+
+        assertThat(isDm).isTrue()
+    }
+
+    @Test
+    fun `a room can be a DM if it has also a single active user`() {
+        val isDirect = true
+        val activeMembersCount = 1
+
+        val isDm = isDm(isDirect, activeMembersCount)
+
+        assertThat(isDm).isTrue()
+    }
+
+    @Test
+    fun `a room is not a DM if it's not direct`() {
+        val isDirect = false
+        val activeMembersCount = 2
+
+        val isDm = isDm(isDirect, activeMembersCount)
+
+        assertThat(isDm).isFalse()
+    }
+
+    @Test
+    fun `a room is not a DM if it has more than 2 active users`() {
+        val isDirect = true
+        val activeMembersCount = 3
+
+        val isDm = isDm(isDirect, activeMembersCount)
+
+        assertThat(isDm).isFalse()
+    }
+}