Persist selected users in data store

features/userlist/api/src/main/kotlin/io/element/android/features/userlist/api/UserListDataStore.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023 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.features.userlist.api
+
+import io.element.android.libraries.matrix.ui.model.MatrixUser
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import javax.inject.Inject
+
+class UserListDataStore @Inject constructor() {
+
+    private val selectedUsers: MutableStateFlow<List<MatrixUser>> = MutableStateFlow(emptyList())
+
+    fun selectUser(user: MatrixUser) {
+        selectedUsers.tryEmit(selectedUsers.value.plus(user))
+    }
+
+    fun removeUserFromSelection(user: MatrixUser) {
+        selectedUsers.tryEmit(selectedUsers.value.minus(user))
+    }
+
+    fun selectedUsers(): Flow<List<MatrixUser>> = selectedUsers
+}

features/userlist/api/src/main/kotlin/io/element/android/features/userlist/api/UserListPresenter.kt

@@ -21,6 +21,10 @@ import io.element.android.libraries.architecture.Presenter
 interface UserListPresenter : Presenter<UserListState> {
 
     interface Factory {
-        fun create(args: UserListPresenterArgs, userListDataSource: UserListDataSource): UserListPresenter
+        fun create(
+            args: UserListPresenterArgs,
+            userListDataSource: UserListDataSource,
+            userListDataStore: UserListDataStore,
+        ): UserListPresenter
     }
 }