Add /myroomnick slash command to change your display name in the current room

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

@@ -212,4 +212,11 @@ interface JoinedRoom : BaseRoom {
      * @return Result indicating success or failure.
      */
     suspend fun sendLiveLocation(geoUri: String): Result<Unit>
+
+    /**
+     * Sets the display name of the current user within this room.
+     * This is different from the global setDisplayName which updates
+     * the user's display name across all of their rooms.
+     */
+    suspend fun setOwnMemberDisplayName(displayName: String): Result<Unit>
 }

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/room/JoinedRustRoom.kt

@@ -546,6 +546,12 @@ class JoinedRustRoom(
         }
     }
 
+    override suspend fun setOwnMemberDisplayName(displayName: String): Result<Unit> = withContext(roomDispatcher) {
+        runCatchingExceptions {
+            innerRoom.setOwnMemberDisplayName(displayName)
+        }
+    }
+
     override fun close() = destroy()
 
     override fun destroy() {

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/room/FakeJoinedRoom.kt

@@ -92,6 +92,7 @@ class FakeJoinedRoom(
     private val startLiveLocationShareResult: (Long) -> Result<EventId> = { lambdaError() },
     private val stopLiveLocationShareResult: () -> Result<Unit> = { lambdaError() },
     private val sendLiveLocationResult: (String) -> Result<Unit> = { lambdaError() },
+    private val setOwnMemberDisplayNameResult: (String) -> Result<Unit> = { lambdaError() },
 ) : JoinedRoom, BaseRoom by baseRoom {
     private val sendQueueUpdates = MutableSharedFlow<SendQueueUpdate>(extraBufferCapacity = 10)
 
@@ -255,6 +256,10 @@ class FakeJoinedRoom(
         sendLiveLocationResult(geoUri)
     }
 
+    override suspend fun setOwnMemberDisplayName(displayName: String): Result<Unit> = simulateLongTask {
+        setOwnMemberDisplayNameResult(displayName)
+    }
+
     private suspend fun simulateSendMediaProgress(progressCallback: ProgressCallback?) {
         progressCallbackValues.forEach { (current, total) ->
             progressCallback?.onProgress(current, total)

libraries/slashcommands/impl/src/main/kotlin/io/element/android/libraries/slashcommands/impl/Command.kt

@@ -109,7 +109,7 @@ enum class Command(
         parameters = "<display-name>",
         description = R.string.slash_command_description_nick_for_room,
         isAllowedInThread = false,
-        isSupported = false,
+        isSupported = true,
     ),
     ROOM_AVATAR(
         command = "/roomavatar",

libraries/slashcommands/impl/src/main/kotlin/io/element/android/libraries/slashcommands/impl/CommandExecutor.kt

@@ -47,7 +47,7 @@ class CommandExecutor(
             is SlashCommand.ChangeAvatar -> changeAvatar()
             is SlashCommand.ChangeAvatarForRoom -> changeAvatarForRoom()
             is SlashCommand.ChangeDisplayName -> changeDisplayName(slashCommand)
-            is SlashCommand.ChangeDisplayNameForRoom -> changeDisplayNameForRoom()
+            is SlashCommand.ChangeDisplayNameForRoom -> changeDisplayNameForRoom(slashCommand)
             is SlashCommand.ChangeRoomAvatar -> changeRoomAvatar()
             is SlashCommand.ChangeRoomName -> changeRoomName(slashCommand)
             is SlashCommand.ChangeTopic -> changeTopic(slashCommand)
@@ -171,8 +171,8 @@ class CommandExecutor(
         return Result.failure(Exception("Not yet implemented"))
     }
 
-    private fun changeDisplayNameForRoom(): Result<Unit> {
-        return Result.failure(Exception("Not yet implemented"))
+    private suspend fun changeDisplayNameForRoom(slashCommand: SlashCommand.ChangeDisplayNameForRoom): Result<Unit> {
+        return joinedRoom.setOwnMemberDisplayName(slashCommand.displayName)
     }
 
     private suspend fun changeDisplayName(slashCommand: SlashCommand.ChangeDisplayName): Result<Unit> {

libraries/slashcommands/impl/src/test/kotlin/io/element/android/libraries/slashcommands/impl/CommandExecutorTest.kt

@@ -14,7 +14,6 @@ import io.element.android.libraries.matrix.api.timeline.MsgType
 import io.element.android.libraries.matrix.test.AN_AVATAR_URL
 import io.element.android.libraries.matrix.test.A_MESSAGE
 import io.element.android.libraries.matrix.test.A_USER_ID
-import io.element.android.libraries.matrix.test.A_USER_NAME
 import io.element.android.libraries.matrix.test.FakeMatrixClient
 import io.element.android.libraries.matrix.test.room.FakeBaseRoom
 import io.element.android.libraries.matrix.test.room.FakeJoinedRoom
@@ -185,10 +184,18 @@ class CommandExecutorTest {
     }
 
     @Test
-    fun `change display name for room is not supported`() = runTest {
-        val sut = createCommandExecutor()
-        val res = sut.proceedAdmin(SlashCommand.ChangeDisplayNameForRoom(A_USER_NAME))
-        assertThat(res.isFailure).isTrue()
+    fun `change display name for room delegates to joined room`() = runTest {
+        var capturedDisplayName: String? = null
+        val joinedRoom = FakeJoinedRoom(
+            setOwnMemberDisplayNameResult = { displayName ->
+                capturedDisplayName = displayName
+                Result.success(Unit)
+            }
+        )
+        val sut = createCommandExecutor(joinedRoom = joinedRoom)
+        val res = sut.proceedAdmin(SlashCommand.ChangeDisplayNameForRoom("room nick"))
+        assertThat(res.isSuccess).isTrue()
+        assertThat(capturedDisplayName).isEqualTo("room nick")
     }
 
     @Test