Move Analytics from Managers to Modules.

Riot/Modules/Analytics/AnalyticsScreenTimer.swift

@@ -0,0 +1,82 @@
+// 
+// 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
+
+/// An object to record how long a screen has been presented for and
+/// report the screen's display to the `Analytics` object.
+@objcMembers class AnalyticsScreenTimer: NSObject {
+    
+    // MARK: - Properties
+    
+    /// The screen being tracked.
+    private let screen: AnalyticsScreen
+    
+    /// The date that the screen was presented to the user.
+    private var startDate: Date?
+    /// Whether the app was backgrounded whilst the screen was being presented.
+    private var didPause = false
+    
+    /// The duration in milliseconds that the screen has been shown for. The value will
+    /// be reported as `nil` if the timer isn't running, or if the app was backgrounded
+    /// during the screen's display.
+    private var duration: Int? {
+        guard let startDate = startDate else {
+            MXLog.warning("[AnalyticsScreenTimer] Duration requested on a stopped timer!")
+            return nil
+        }
+        
+        // Consider the duration invalid if the app has been backgrounded
+        guard !didPause else { return nil }
+        
+        let timeInterval = Date().timeIntervalSince(startDate)
+        return Int(timeInterval * 1000)
+    }
+    
+    // MARK: - Setup
+    
+    /// Create a new screen timer for the specified screen.
+    /// - Parameter screen: The screen that should be timed.
+    init(screen: AnalyticsScreen) {
+        self.screen = screen
+        
+        super.init()
+        
+        NotificationCenter.default.addObserver(self, selector: #selector(pause), name: UIApplication.willResignActiveNotification, object: nil)
+    }
+    
+    // MARK: - Public
+    
+    /// Start the timer.
+    func start() {
+        startDate = Date()
+    }
+    
+    /// Stop the timer and report the screen to `Analytics`.
+    func stop() {
+        guard let duration = duration else { return }
+        
+        Analytics.shared.trackScreen(screen, duration: duration)
+        self.startDate = nil
+    }
+    
+    // MARK: - Private
+    
+    /// Record that the timer has been interrupted by the app moving to the background.
+    @objc private func pause() {
+        didPause = true
+    }
+}