Initial implementation of the JoinRoomScreen. (#2684)

* Update Compound and use super button for room directory.

ElementX/Sources/Screens/JoinRoomScreen/JoinRoomScreenModels.swift

@@ -0,0 +1,74 @@
+//
+// Copyright 2022 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.
+//
+
+import Foundation
+
+enum JoinRoomScreenViewModelAction {
+    case joined
+    case cancelled
+}
+
+struct JoinRoomScreenViewState: BindableState {
+    // Maybe use room summary details or similar here??
+    let roomID: String
+    let roomName: String
+    let avatarURL: URL?
+    
+    let interaction: JoinRoomScreenInteraction
+    
+    var isJoining = false
+    
+    var bindings = JoinRoomScreenViewStateBindings()
+    
+    var title: String {
+        switch interaction {
+        case .knock:
+            L10n.screenJoinRoomTitleKnock
+        case .join, .invited:
+            L10n.screenJoinRoomTitleNoPreview
+        }
+    }
+    
+    var subtitle: String {
+        switch interaction {
+        case .knock:
+            L10n.screenJoinRoomSubtitleKnock
+        case .join, .invited:
+            L10n.screenJoinRoomSubtitleNoPreview
+        }
+    }
+}
+
+struct JoinRoomScreenViewStateBindings {
+    var alertInfo: AlertInfo<JoinRoomScreenAlertType>?
+}
+
+enum JoinRoomScreenAlertType {
+    case joinFailed
+}
+
+enum JoinRoomScreenInteraction {
+    case knock
+    case join
+    case invited
+}
+
+enum JoinRoomScreenViewAction {
+    case knock
+    case join
+    case acceptInvite
+    case declineInvite
+}