Add thread notification dots

Riot/Modules/Threads/ThreadList/Views/Cell/ThreadNotificationStatusView.swift

@@ -0,0 +1,52 @@
+// 
+// Copyright 2021 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 UIKit
+
+/// Dot view for a thread notification status
+class ThreadNotificationStatusView: UIView {
+    
+    private var theme: Theme = ThemeService.shared().theme
+    
+    /// Current status. Update this property to change background color accordingly.
+    var status: ThreadNotificationStatus = .none {
+        didSet {
+            updateBgColor()
+        }
+    }
+    
+    private func updateBgColor() {
+        switch status {
+        case .none:
+            backgroundColor = .clear
+        case .notified:
+            backgroundColor = theme.colors.secondaryContent
+        case .highlighted:
+            backgroundColor = theme.colors.alert
+        }
+    }
+    
+}
+
+extension ThreadNotificationStatusView: Themable {
+    
+    func update(theme: Theme) {
+        self.theme = theme
+        
+        updateBgColor()
+    }
+    
+}