#40: Add the login screen from EI.

- Remove SSO and replace fallback with OIDC.

ElementX/Sources/Screens/Authentication/LoginScreen/LoginMode.swift

@@ -0,0 +1,56 @@
+// 
+// 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
+
+/// The supported forms of login that a homeserver allows.
+enum LoginMode: Equatable {
+    /// The login mode hasn't been determined yet.
+    case unknown
+    /// The homeserver supports login via OpenID Connect at the associated URL.
+    case oidc(URL)
+    /// The homeserver supports login with a password.
+    case password
+    /// The homeserver only allows login with unsupported mechanisms. Use fallback instead.
+    case unsupported
+    
+    var supportsOIDCFlow: Bool {
+        switch self {
+        case .oidc:
+            return true
+        default:
+            return false
+        }
+    }
+    
+    var supportsPasswordFlow: Bool {
+        switch self {
+        case .password:
+            return true
+        default:
+            return false
+        }
+    }
+
+    var isUnsupported: Bool {
+        switch self {
+        case .unsupported:
+            return true
+        default:
+            return false
+        }
+    }
+}