Direct room: finally use PagedList as we can get a lot of users in DB.

matrix-sdk-android-rx/build.gradle

@@ -38,6 +38,8 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.1.0-beta01'
     implementation 'io.reactivex.rxjava2:rxkotlin:2.3.0'
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
+    // Paging
+    implementation "androidx.paging:paging-runtime-ktx:2.1.0"
 
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test:runner:1.2.0'

matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxSession.kt

@@ -16,6 +16,7 @@
 
 package im.vector.matrix.rx
 
+import androidx.paging.PagedList
 import im.vector.matrix.android.api.session.Session
 import im.vector.matrix.android.api.session.group.model.GroupSummary
 import im.vector.matrix.android.api.session.pushers.Pusher
@@ -48,6 +49,10 @@ class RxSession(private val session: Session) {
         return session.liveUsers().asObservable()
     }
 
+    fun livePagedUsers(filter: String? = null): Observable<PagedList<User>> {
+        return session.livePagedUsers(filter).asObservable()
+    }
+
     fun createRoom(roomParams: CreateRoomParams): Single<String> = Single.create {
         session.createRoom(roomParams, MatrixCallbackSingle(it)).toSingle(it)
     }

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/user/UserService.kt

@@ -17,6 +17,7 @@
 package im.vector.matrix.android.api.session.user
 
 import androidx.lifecycle.LiveData
+import androidx.paging.PagedList
 import im.vector.matrix.android.api.MatrixCallback
 import im.vector.matrix.android.api.session.user.model.User
 import im.vector.matrix.android.api.util.Cancelable
@@ -56,4 +57,11 @@ interface UserService {
      */
     fun liveUsers(): LiveData<List<User>>
 
+    /**
+     * Observe a live [PagedList] of users sorted alphabetically. You can filter the users.
+     * @param filter the filter. It will look into userId and displayName.
+     * @return a Livedata of users
+     */
+    fun livePagedUsers(filter: String? = null): LiveData<PagedList<User>>
+
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/RealmQueryLatch.kt

@@ -19,14 +19,17 @@ package im.vector.matrix.android.internal.database
 import android.os.Handler
 import android.os.HandlerThread
 import io.realm.*
+import timber.log.Timber
 import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
 
 private const val THREAD_NAME = "REALM_QUERY_LATCH"
 
 class RealmQueryLatch<E : RealmObject>(private val realmConfiguration: RealmConfiguration,
                                        private val realmQueryBuilder: (Realm) -> RealmQuery<E>) {
 
-    fun await() {
+    @Throws(InterruptedException::class)
+    fun await(timeout: Long = Long.MAX_VALUE, timeUnit: TimeUnit = TimeUnit.MILLISECONDS) {
         val latch = CountDownLatch(1)
         val handlerThread = HandlerThread(THREAD_NAME + hashCode())
         handlerThread.start()
@@ -46,9 +49,14 @@ class RealmQueryLatch<E : RealmObject>(private val realmConfiguration: RealmConf
             })
         }
         handler.post(runnable)
-        latch.await()
+        try {
+            latch.await(timeout, timeUnit)
+        } catch (exception: InterruptedException) {
+            throw exception
+        } finally {
             handlerThread.quit()
         }
+    }
 
 
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/create/CreateRoomTask.kt

@@ -34,6 +34,7 @@ import im.vector.matrix.android.internal.session.user.accountdata.UpdateUserAcco
 import im.vector.matrix.android.internal.task.Task
 import im.vector.matrix.android.internal.util.tryTransactionSync
 import io.realm.RealmConfiguration
+import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 
 internal interface CreateRoomTask : Task<CreateRoomParams, String>
@@ -56,8 +57,10 @@ internal class DefaultCreateRoomTask @Inject constructor(private val roomAPI: Ro
                 realm.where(RoomEntity::class.java)
                         .equalTo(RoomEntityFields.ROOM_ID, roomId)
             }
-            rql.await()
+            Try {
-            Try.just(roomId)
+                rql.await(timeout = 20L, timeUnit = TimeUnit.SECONDS)
+                roomId
+            }
         }.flatMap { roomId ->
             if (params.isDirect()) {
                 handleDirectChatCreation(params, roomId)

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/membership/joining/JoinRoomTask.kt

@@ -26,6 +26,7 @@ import im.vector.matrix.android.internal.session.room.RoomAPI
 import im.vector.matrix.android.internal.session.room.read.SetReadMarkersTask
 import im.vector.matrix.android.internal.task.Task
 import io.realm.RealmConfiguration
+import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 
 internal interface JoinRoomTask : Task<JoinRoomTask.Params, Unit> {
@@ -48,8 +49,10 @@ internal class DefaultJoinRoomTask @Inject constructor(private val roomAPI: Room
                 realm.where(RoomEntity::class.java)
                         .equalTo(RoomEntityFields.ROOM_ID, roomId)
             }
-            rql.await()
+            Try {
-            Try.just(roomId)
+                rql.await(20L, TimeUnit.SECONDS)
+                roomId
+            }
         }.flatMap { roomId ->
             setReadMarkers(roomId)
         }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/user/DefaultUserService.kt

@@ -18,6 +18,9 @@ package im.vector.matrix.android.internal.session.user
 
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Transformations
+import androidx.paging.DataSource
+import androidx.paging.LivePagedListBuilder
+import androidx.paging.PagedList
 import com.zhuinden.monarchy.Monarchy
 import im.vector.matrix.android.api.MatrixCallback
 import im.vector.matrix.android.api.session.user.UserService
@@ -38,6 +41,24 @@ internal class DefaultUserService @Inject constructor(private val monarchy: Mona
                                                       private val searchUserTask: SearchUserTask,
                                                       private val taskExecutor: TaskExecutor) : UserService {
 
+    private val realmDataSourceFactory: Monarchy.RealmDataSourceFactory<UserEntity> by lazy {
+        monarchy.createDataSourceFactory { realm ->
+            realm.where(UserEntity::class.java)
+                    .isNotEmpty(UserEntityFields.USER_ID)
+                    .sort(UserEntityFields.DISPLAY_NAME)
+        }
+    }
+
+    private val domainDataSourceFactory: DataSource.Factory<Int, User> by lazy {
+        realmDataSourceFactory.map {
+            it.asDomain()
+        }
+    }
+
+    private val livePagedListBuilder: LivePagedListBuilder<Int, User> by lazy {
+        LivePagedListBuilder(domainDataSourceFactory, PagedList.Config.Builder().setPageSize(100).setEnablePlaceholders(false).build())
+    }
+
     override fun getUser(userId: String): User? {
         val userEntity = monarchy.fetchCopied { UserEntity.where(it, userId).findFirst() }
                          ?: return null
@@ -67,6 +88,25 @@ internal class DefaultUserService @Inject constructor(private val monarchy: Mona
         )
     }
 
+    override fun livePagedUsers(filter: String?): LiveData<PagedList<User>> {
+        realmDataSourceFactory.updateQuery { realm ->
+            val query = realm.where(UserEntity::class.java)
+            if (filter.isNullOrEmpty()) {
+                query.isNotEmpty(UserEntityFields.USER_ID)
+            } else {
+                query
+                        .beginGroup()
+                        .contains(UserEntityFields.DISPLAY_NAME, filter)
+                        .or()
+                        .contains(UserEntityFields.USER_ID, filter)
+                        .endGroup()
+            }
+            query.sort(UserEntityFields.DISPLAY_NAME)
+        }
+        return monarchy.findAllPagedWithChanges(realmDataSourceFactory, livePagedListBuilder)
+    }
+
+
     override fun searchUsersDirectory(search: String,
                                       limit: Int,
                                       excludedUserIds: Set<String>,

vector/build.gradle

@@ -148,7 +148,7 @@ android {
 
 dependencies {
 
-    def epoxy_version = "3.3.0"
+    def epoxy_version = "3.7.0"
     def arrow_version = "0.8.2"
     def coroutines_version = "1.0.1"
     def markwon_version = '3.0.0'
@@ -193,11 +193,15 @@ dependencies {
 
     implementation("com.airbnb.android:epoxy:$epoxy_version")
     kapt "com.airbnb.android:epoxy-processor:$epoxy_version"
+    implementation "com.airbnb.android:epoxy-paging:$epoxy_version"
     implementation 'com.airbnb.android:mvrx:1.0.1'
 
     // Work
     implementation "androidx.work:work-runtime-ktx:2.1.0-rc01"
 
+    // Paging
+    implementation "androidx.paging:paging-runtime-ktx:2.1.0"
+
     // Functional Programming
     implementation "io.arrow-kt:arrow-core:$arrow_version"
 

vector/src/main/java/im/vector/riotx/core/di/ScreenComponent.kt

@@ -38,7 +38,7 @@ import im.vector.riotx.features.home.HomeDrawerFragment
 import im.vector.riotx.features.home.HomeModule
 import im.vector.riotx.features.home.createdirect.CreateDirectRoomActivity
 import im.vector.riotx.features.home.createdirect.CreateDirectRoomDirectoryUsersFragment
-import im.vector.riotx.features.home.createdirect.CreateDirectRoomFragment
+import im.vector.riotx.features.home.createdirect.CreateDirectRoomKnownUsersFragment
 import im.vector.riotx.features.home.group.GroupListFragment
 import im.vector.riotx.features.home.room.detail.RoomDetailFragment
 import im.vector.riotx.features.home.room.detail.timeline.action.*
@@ -159,7 +159,7 @@ interface ScreenComponent {
 
     fun inject(pushGatewaysFragment: PushGatewaysFragment)
 
-    fun inject(createDirectRoomKnownUsersFragment: CreateDirectRoomFragment)
+    fun inject(createDirectRoomKnownUsersFragment: CreateDirectRoomKnownUsersFragment)
 
     fun inject(createDirectRoomDirectoryUsersFragment: CreateDirectRoomDirectoryUsersFragment)
 

vector/src/main/java/im/vector/riotx/features/home/createdirect/CreateDirectRoomActivity.kt

@@ -70,7 +70,7 @@ class CreateDirectRoomActivity : SimpleFragmentActivity() {
             }
         }
         if (isFirstCreation()) {
-            addFragment(CreateDirectRoomFragment(), R.id.container)
+            addFragment(CreateDirectRoomKnownUsersFragment(), R.id.container)
         }
         viewModel.selectSubscribe(this, CreateDirectRoomViewState::createAndInviteState) {
             renderCreateAndInviteState(it)

vector/src/main/java/im/vector/riotx/features/home/createdirect/CreateDirectRoomDirectoryUsersFragment.kt

@@ -32,13 +32,13 @@ import im.vector.riotx.core.platform.VectorBaseFragment
 import kotlinx.android.synthetic.main.fragment_create_direct_room_directory_users.*
 import javax.inject.Inject
 
-class CreateDirectRoomDirectoryUsersFragment : VectorBaseFragment(), CreateDirectRoomController.Callback {
+class CreateDirectRoomDirectoryUsersFragment : VectorBaseFragment(), DirectoryUsersController.Callback {
 
     override fun getLayoutResId() = R.layout.fragment_create_direct_room_directory_users
 
     private val viewModel: CreateDirectRoomViewModel by activityViewModel()
 
-    @Inject lateinit var directRoomController: CreateDirectRoomController
+    @Inject lateinit var directRoomController: DirectoryUsersController
     private lateinit var navigationViewModel: CreateDirectRoomNavigationViewModel
 
     override fun injectWith(injector: ScreenComponent) {
@@ -56,7 +56,6 @@ class CreateDirectRoomDirectoryUsersFragment : VectorBaseFragment(), CreateDirec
     private fun setupRecyclerView() {
         recyclerView.setHasFixedSize(true)
         directRoomController.callback = this
-        directRoomController.displayMode = CreateDirectRoomViewState.DisplayMode.DIRECTORY_USERS
         recyclerView.setController(directRoomController)
     }
 
@@ -76,7 +75,7 @@ class CreateDirectRoomDirectoryUsersFragment : VectorBaseFragment(), CreateDirec
 
     private fun setupCloseView() {
         createDirectRoomClose.setOnClickListener {
-            navigationViewModel.goTo(CreateDirectRoomActivity.Navigation.Close)
+            navigationViewModel.goTo(CreateDirectRoomActivity.Navigation.Previous)
         }
     }
 

vector/src/main/java/im/vector/riotx/features/home/createdirect/CreateDirectRoomKnownUsersFragment.kt

@@ -41,7 +41,7 @@ import im.vector.riotx.features.home.AvatarRenderer
 import kotlinx.android.synthetic.main.fragment_create_direct_room.*
 import javax.inject.Inject
 
-class CreateDirectRoomFragment : VectorBaseFragment(), CreateDirectRoomController.Callback {
+class CreateDirectRoomKnownUsersFragment : VectorBaseFragment(), KnownUsersController.Callback {
 
     override fun getLayoutResId() = R.layout.fragment_create_direct_room
 
@@ -49,7 +49,7 @@ class CreateDirectRoomFragment : VectorBaseFragment(), CreateDirectRoomControlle
 
     private val viewModel: CreateDirectRoomViewModel by activityViewModel()
 
-    @Inject lateinit var directRoomController: CreateDirectRoomController
+    @Inject lateinit var directRoomController: KnownUsersController
     @Inject lateinit var avatarRenderer: AvatarRenderer
     private lateinit var navigationViewModel: CreateDirectRoomNavigationViewModel
 
@@ -104,13 +104,13 @@ class CreateDirectRoomFragment : VectorBaseFragment(), CreateDirectRoomControlle
         // Don't activate animation as we might have way to much item animation when filtering
         recyclerView.itemAnimator = null
         directRoomController.callback = this
-        directRoomController.displayMode = CreateDirectRoomViewState.DisplayMode.KNOWN_USERS
         recyclerView.setController(directRoomController)
     }
 
     private fun setupFilterView() {
         createDirectRoomFilter
                 .textChanges()
+                .startWith(createDirectRoomFilter.text)
                 .subscribe { text ->
                     val filterValue = text.trim()
                     val action = if (filterValue.isBlank()) {

vector/src/main/java/im/vector/riotx/features/home/createdirect/CreateDirectRoomViewModel.kt

@@ -35,6 +35,7 @@ import im.vector.riotx.core.platform.VectorViewModel
 import im.vector.riotx.core.utils.LiveEvent
 import io.reactivex.Observable
 import io.reactivex.Single
+import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.functions.BiFunction
 import java.util.concurrent.TimeUnit
 
@@ -154,22 +155,13 @@ class CreateDirectRoomViewModel @AssistedInject constructor(@Assisted
     }
 
     private fun observeKnownUsers() {
-        Observable
+        knownUsersFilter
-                .combineLatest<List<User>, Option<KnowUsersFilter>, List<User>>(
+                .throttleLast(300, TimeUnit.MILLISECONDS)
-                        session.rx().liveUsers(),
+                .observeOn(AndroidSchedulers.mainThread())
-                        knownUsersFilter.throttleLast(300, TimeUnit.MILLISECONDS),
+                .switchMap {
-                        BiFunction { users, filter ->
+                    session.rx().livePagedUsers(it.orNull())
-                            val filterValue = filter.orNull()
-                            if (filterValue.isNullOrEmpty()) {
-                                users
-                            } else {
-                                users.filter {
-                                    it.displayName?.contains(filterValue, ignoreCase = true) ?: false
-                                    || it.userId.contains(filterValue, ignoreCase = true)
                 }
-                            }
+                .execute { async ->
-                        }
-                ).execute { async ->
                     copy(
                             knownUsers = async,
                             filterKnownUsersValue = knownUsersFilter.value ?: Option.empty()

vector/src/main/java/im/vector/riotx/features/home/createdirect/CreateDirectRoomViewState.kt

@@ -18,6 +18,7 @@
 
 package im.vector.riotx.features.home.createdirect
 
+import androidx.paging.PagedList
 import arrow.core.Option
 import com.airbnb.mvrx.Async
 import com.airbnb.mvrx.MvRxState
@@ -25,7 +26,7 @@ import com.airbnb.mvrx.Uninitialized
 import im.vector.matrix.android.api.session.user.model.User
 
 data class CreateDirectRoomViewState(
-        val knownUsers: Async<List<User>> = Uninitialized,
+        val knownUsers: Async<PagedList<User>> = Uninitialized,
         val directoryUsers: Async<List<User>> = Uninitialized,
         val selectedUsers: Set<User> = emptySet(),
         val createAndInviteState: Async<String> = Uninitialized,

vector/src/main/java/im/vector/riotx/features/home/createdirect/DirectoryUsersController.kt

@@ -32,13 +32,12 @@ import im.vector.riotx.core.resources.StringProvider
 import im.vector.riotx.features.home.AvatarRenderer
 import javax.inject.Inject
 
-class CreateDirectRoomController @Inject constructor(private val session: Session,
+class DirectoryUsersController @Inject constructor(private val session: Session,
                                                    private val avatarRenderer: AvatarRenderer,
                                                    private val stringProvider: StringProvider,
                                                    private val errorFormatter: ErrorFormatter) : EpoxyController() {
 
     private var state: CreateDirectRoomViewState? = null
-    var displayMode = CreateDirectRoomViewState.DisplayMode.KNOWN_USERS
 
     var callback: Callback? = null
 
@@ -51,19 +50,15 @@ class CreateDirectRoomController @Inject constructor(private val session: Sessio
         requestModelBuild()
     }
 
+
     override fun buildModels() {
         val currentState = state ?: return
         val hasSearch = currentState.directorySearchTerm.isNotBlank()
-        val isFiltering = currentState.filterKnownUsersValue.nonEmpty()
+        val asyncUsers = currentState.directoryUsers
-        val asyncUsers = if (displayMode == CreateDirectRoomViewState.DisplayMode.DIRECTORY_USERS) {
-            currentState.directoryUsers
-        } else {
-            currentState.knownUsers
-        }
         when (asyncUsers) {
             is Uninitialized -> renderEmptyState(false)
             is Loading       -> renderLoading()
-            is Success       -> renderSuccess(asyncUsers(), currentState.selectedUsers.map { it.userId }, hasSearch, isFiltering)
+            is Success       -> renderSuccess(asyncUsers(), currentState.selectedUsers.map { it.userId }, hasSearch)
             is Fail          -> renderFailure(asyncUsers.error)
         }
     }
@@ -84,31 +79,20 @@ class CreateDirectRoomController @Inject constructor(private val session: Sessio
 
     private fun renderSuccess(users: List<User>,
                               selectedUsers: List<String>,
-                              hasSearch: Boolean,
+                              hasSearch: Boolean) {
-                              isFiltering: Boolean) {
         if (users.isEmpty()) {
             renderEmptyState(hasSearch)
         } else {
-            renderUsers(users, selectedUsers, isFiltering)
+            renderUsers(users, selectedUsers)
         }
     }
 
-    private fun renderUsers(users: List<User>, selectedUsers: List<String>, isFiltering: Boolean) {
+    private fun renderUsers(users: List<User>, selectedUsers: List<String>) {
-        var lastFirstLetter: String? = null
         for (user in users) {
             if (user.userId == session.myUserId) {
                 continue
             }
             val isSelected = selectedUsers.contains(user.userId)
-            val currentFirstLetter = user.displayName.firstLetterOfDisplayName()
-            val showLetter = !isFiltering && currentFirstLetter.isNotEmpty() && lastFirstLetter != currentFirstLetter
-            lastFirstLetter = currentFirstLetter
-
-            CreateDirectRoomLetterHeaderItem_()
-                    .id(currentFirstLetter)
-                    .letter(currentFirstLetter)
-                    .addIf(showLetter, this)
-
             createDirectRoomUserItem {
                 id(user.userId)
                 selected(isSelected)
@@ -124,15 +108,11 @@ class CreateDirectRoomController @Inject constructor(private val session: Sessio
     }
 
     private fun renderEmptyState(hasSearch: Boolean) {
-        val noResultRes = if (displayMode == CreateDirectRoomViewState.DisplayMode.DIRECTORY_USERS) {
+        val noResultRes = if (hasSearch) {
-            if (hasSearch) {
             R.string.no_result_placeholder
         } else {
             R.string.direct_room_start_search
         }
-        } else {
-            R.string.direct_room_no_known_users
-        }
         noResultItem {
             id("noResult")
             text(stringProvider.getString(noResultRes))
@@ -141,9 +121,7 @@ class CreateDirectRoomController @Inject constructor(private val session: Sessio
 
     interface Callback {
         fun onItemClick(user: User)
-        fun retryDirectoryUsersRequest() {
+        fun retryDirectoryUsersRequest()
-            // NO-OP
-        }
     }
 
 }

vector/src/main/java/im/vector/riotx/features/home/createdirect/KnownUsersController.kt

@@ -0,0 +1,130 @@
+/*
+ * Copyright 2019 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 im.vector.riotx.features.home.createdirect
+
+import com.airbnb.epoxy.EpoxyModel
+import com.airbnb.epoxy.paging.PagedListEpoxyController
+import com.airbnb.mvrx.Async
+import com.airbnb.mvrx.Fail
+import com.airbnb.mvrx.Incomplete
+import com.airbnb.mvrx.Loading
+import com.airbnb.mvrx.Success
+import com.airbnb.mvrx.Uninitialized
+import im.vector.matrix.android.api.session.Session
+import im.vector.matrix.android.api.session.user.model.User
+import im.vector.matrix.android.internal.util.createUIHandler
+import im.vector.matrix.android.internal.util.firstLetterOfDisplayName
+import im.vector.riotx.R
+import im.vector.riotx.core.epoxy.EmptyItem_
+import im.vector.riotx.core.epoxy.errorWithRetryItem
+import im.vector.riotx.core.epoxy.loadingItem
+import im.vector.riotx.core.epoxy.noResultItem
+import im.vector.riotx.core.error.ErrorFormatter
+import im.vector.riotx.core.resources.StringProvider
+import im.vector.riotx.features.home.AvatarRenderer
+import javax.inject.Inject
+
+class KnownUsersController @Inject constructor(private val session: Session,
+                                               private val avatarRenderer: AvatarRenderer,
+                                               private val stringProvider: StringProvider) : PagedListEpoxyController<User>(
+        modelBuildingHandler = createUIHandler()
+) {
+
+    private var selectedUsers: List<String> = emptyList()
+    private var users: Async<List<User>> = Uninitialized
+    private var isFiltering: Boolean = false
+
+    var callback: Callback? = null
+
+    init {
+        requestModelBuild()
+    }
+
+    fun setData(state: CreateDirectRoomViewState) {
+        this.isFiltering = !state.filterKnownUsersValue.isEmpty()
+        val newSelection = state.selectedUsers.map { it.userId }
+        this.users = state.knownUsers
+        if (newSelection != selectedUsers) {
+            this.selectedUsers = newSelection
+            requestForcedModelBuild()
+        }
+        submitList(state.knownUsers())
+    }
+
+    override fun buildItemModel(currentPosition: Int, item: User?): EpoxyModel<*> {
+        return if (item == null) {
+            EmptyItem_().id(currentPosition)
+        } else {
+            val isSelected = selectedUsers.contains(item.userId)
+            CreateDirectRoomUserItem_()
+                    .id(item.userId)
+                    .selected(isSelected)
+                    .userId(item.userId)
+                    .name(item.displayName)
+                    .avatarUrl(item.avatarUrl)
+                    .avatarRenderer(avatarRenderer)
+                    .clickListener { _ ->
+                        callback?.onItemClick(item)
+                    }
+        }
+    }
+
+    override fun addModels(models: List<EpoxyModel<*>>) {
+        if (users is Incomplete) {
+            renderLoading()
+        } else if (models.isEmpty()) {
+            renderEmptyState()
+        } else {
+            var lastFirstLetter: String? = null
+            for (model in models) {
+                if (model is CreateDirectRoomUserItem) {
+                    if (model.userId == session.myUserId) continue
+                    val currentFirstLetter = model.name.firstLetterOfDisplayName()
+                    val showLetter = !isFiltering && currentFirstLetter.isNotEmpty() && lastFirstLetter != currentFirstLetter
+                    lastFirstLetter = currentFirstLetter
+
+                    CreateDirectRoomLetterHeaderItem_()
+                            .id(currentFirstLetter)
+                            .letter(currentFirstLetter)
+                            .addIf(showLetter, this)
+
+                    model.addTo(this)
+                } else {
+                    continue
+                }
+            }
+        }
+    }
+
+    private fun renderLoading() {
+        loadingItem {
+            id("loading")
+        }
+    }
+
+    private fun renderEmptyState() {
+        noResultItem {
+            id("noResult")
+            text(stringProvider.getString(R.string.direct_room_no_known_users))
+        }
+    }
+
+    interface Callback {
+        fun onItemClick(user: User)
+    }
+
+}