Merge remote-tracking branch 'upstream/master' into ios-general-fixes

ios/App/Shared/player/AudioPlayer.swift

@@ -19,6 +19,7 @@ enum PlayMethod:Int {
 
 class AudioPlayer: NSObject {
     internal let queue = DispatchQueue(label: "ABSAudioPlayerQueue")
+    internal let logger = AppLogger(category: "AudioPlayer")
     
     // enums and @objc are not compatible
     @objc dynamic var status: Int
@@ -68,7 +69,7 @@ class AudioPlayer: NSObject {
         
         let playbackSession = self.getPlaybackSession()
         guard let playbackSession = playbackSession else {
-            NSLog("Failed to fetch playback session. Player will not initialize")
+            logger.error("Failed to fetch playback session. Player will not initialize")
             NotificationCenter.default.post(name: NSNotification.Name(PlayerEvents.failed.rawValue), object: nil)
             return
         }
@@ -86,10 +87,10 @@ class AudioPlayer: NSObject {
         }
         
         self.currentTrackIndex = getItemIndexForTime(time: playbackSession.currentTime)
-        NSLog("Starting track index \(self.currentTrackIndex) for start time \(playbackSession.currentTime)")
+        logger.log("Starting track index \(self.currentTrackIndex) for start time \(playbackSession.currentTime)")
         
         let playerItems = self.allPlayerItems[self.currentTrackIndex..<self.allPlayerItems.count]
-        NSLog("Setting player items \(playerItems.count)")
+        logger.log("Setting player items \(playerItems.count)")
         
         for item in Array(playerItems) {
             self.audioPlayer.insert(item, after:self.audioPlayer.items().last)
@@ -99,7 +100,7 @@ class AudioPlayer: NSObject {
         setupQueueObserver()
         setupQueueItemStatusObserver()
 
-        NSLog("Audioplayer ready")
+        logger.log("Audioplayer ready")
     }
     
     deinit {
@@ -120,8 +121,8 @@ class AudioPlayer: NSObject {
         do {
             try AVAudioSession.sharedInstance().setActive(false)
         } catch {
-            NSLog("Failed to set AVAudioSession inactive")
-            print(error)
+            logger.error("Failed to set AVAudioSession inactive")
+            logger.error(error)
         }
         
         self.removeAudioSessionNotifications()
@@ -214,14 +215,14 @@ class AudioPlayer: NSObject {
             self.audioPlayer.currentItem.map { item in
                 self.currentTrackIndex = self.allPlayerItems.firstIndex(of:item) ?? 0
                 if (self.currentTrackIndex != prevTrackIndex) {
-                    NSLog("New Current track index \(self.currentTrackIndex)")
+                    self.logger.log("New Current track index \(self.currentTrackIndex)")
                 }
             }
         }
     }
     
     private func setupQueueItemStatusObserver() {
-        NSLog("queueStatusObserver: Setting up")
+        logger.log("queueStatusObserver: Setting up")
 
         // Listen for player item updates
         self.queueItemStatusObserver?.invalidate()
@@ -236,13 +237,13 @@ class AudioPlayer: NSObject {
     }
     
     private func handleQueueItemStatus(playerItem: AVPlayerItem) {
-        NSLog("queueStatusObserver: Current item status changed")
+        logger.log("queueStatusObserver: Current item status changed")
         guard let playbackSession = self.getPlaybackSession() else {
             NotificationCenter.default.post(name: NSNotification.Name(PlayerEvents.failed.rawValue), object: nil)
             return
         }
         if (playerItem.status == .readyToPlay) {
-            NSLog("queueStatusObserver: Current Item Ready to play. PlayWhenReady: \(self.playWhenReady)")
+            logger.log("queueStatusObserver: Current Item Ready to play. PlayWhenReady: \(self.playWhenReady)")
             
             // Seek the player before initializing, so a currentTime of 0 does not appear in MediaProgress / session
             let firstReady = self.status < 0
@@ -261,7 +262,7 @@ class AudioPlayer: NSObject {
                 self.play()
             }
         } else if (playerItem.status == .failed) {
-            NSLog("queueStatusObserver: FAILED \(playerItem.error?.localizedDescription ?? "")")
+            logger.error("queueStatusObserver: FAILED \(playerItem.error?.localizedDescription ?? "")")
             NotificationCenter.default.post(name: NSNotification.Name(PlayerEvents.failed.rawValue), object: nil)
         }
     }
@@ -269,8 +270,8 @@ class AudioPlayer: NSObject {
     private func startPausedTimer() {
         guard self.pausedTimer == nil else { return }
         self.queue.async {
-            self.pausedTimer = Timer.scheduledTimer(withTimeInterval: 10, repeats: true) { timer in
-                NSLog("PAUSE TIMER: Syncing from server")
+            self.pausedTimer = Timer.scheduledTimer(withTimeInterval: 10, repeats: true) { [weak self] timer in
+                self?.logger.log("PAUSE TIMER: Syncing from server")
                 Task { await PlayerProgress.shared.syncFromServer() }
             }
         }
@@ -334,7 +335,7 @@ class AudioPlayer: NSObject {
     }
     
     private func resumePlayback() {
-        NSLog("PLAY: Resuming playback")
+        logger.log("PLAY: Resuming playback")
         
         // Stop the paused timer
         self.stopPausedTimer()
@@ -353,7 +354,7 @@ class AudioPlayer: NSObject {
     public func pause() {
         guard self.isInitialized() else { return }
         
-        NSLog("PAUSE: Pausing playback")
+        logger.log("PAUSE: Pausing playback")
         DispatchQueue.runOnMainQueue {
             self.audioPlayer.pause()
         }
@@ -377,17 +378,17 @@ class AudioPlayer: NSObject {
         
         self.pause()
         
-        NSLog("SEEK: Seek to \(to) from \(from)")
+        logger.log("SEEK: Seek to \(to) from \(from)")
         
         guard let playbackSession = self.getPlaybackSession() else { return }
         
         let currentTrack = playbackSession.audioTracks[self.currentTrackIndex]
         let ctso = currentTrack.startOffset ?? 0.0
         let trackEnd = ctso + currentTrack.duration
-        NSLog("SEEK: Seek current track END = \(trackEnd)")
+        logger.log("SEEK: Seek current track END = \(trackEnd)")
         
         let indexOfSeek = getItemIndexForTime(time: to)
-        NSLog("SEEK: Seek to index \(indexOfSeek) | Current index \(self.currentTrackIndex)")
+        logger.log("SEEK: Seek to index \(indexOfSeek) | Current index \(self.currentTrackIndex)")
         
         // Reconstruct queue if seeking to a different track
         if (self.currentTrackIndex != indexOfSeek) {
@@ -410,13 +411,16 @@ class AudioPlayer: NSObject {
             
             setupQueueItemStatusObserver()
         } else {
-            NSLog("SEEK: Seeking in current item \(to)")
+            logger.log("SEEK: Seeking in current item \(to)")
             let currentTrackStartOffset = playbackSession.audioTracks[self.currentTrackIndex].startOffset ?? 0.0
             let seekTime = to - currentTrackStartOffset
             
             DispatchQueue.runOnMainQueue {
                 self.audioPlayer.seek(to: CMTime(seconds: seekTime, preferredTimescale: 1000)) { [weak self] completed in
-                    guard completed else { return NSLog("SEEK: WARNING: seeking not completed (to \(seekTime)") }
+                    guard completed else {
+                        self?.logger.log("SEEK: WARNING: seeking not completed (to \(seekTime)")
+                        return
+                    }
                     guard let self = self else { return }
                     
                     if continuePlaying {
@@ -433,7 +437,7 @@ class AudioPlayer: NSObject {
         let playbackSpeedChanged = rate > 0.0 && rate != self.tmpRate && !(observed && rate == 1)
         
         if self.audioPlayer.rate != rate {
-            NSLog("setPlaybakRate rate changed from \(self.audioPlayer.rate) to \(rate)")
+            logger.log("setPlaybakRate rate changed from \(self.audioPlayer.rate) to \(rate)")
             DispatchQueue.runOnMainQueue {
                 self.audioPlayer.rate = rate
             }
@@ -490,7 +494,7 @@ class AudioPlayer: NSObject {
         } else if (playbackSession.playMethod == PlayMethod.local.rawValue) {
             guard let localFile = track.getLocalFile() else {
                 // Worst case we can stream the file
-                NSLog("Unable to play local file. Resulting to streaming \(track.localFileId ?? "Unknown")")
+                logger.log("Unable to play local file. Resulting to streaming \(track.localFileId ?? "Unknown")")
                 let filename = track.metadata?.filename ?? ""
                 let filenameEncoded = filename.addingPercentEncoding(withAllowedCharacters: NSCharacterSet.urlQueryAllowed)
                 let urlstr = "\(Store.serverConfig!.address)/s/item/\(itemId)/\(filenameEncoded ?? "")?token=\(Store.serverConfig!.token)"
@@ -510,8 +514,8 @@ class AudioPlayer: NSObject {
         do {
             try AVAudioSession.sharedInstance().setCategory(.playback, mode: .spokenAudio)
         } catch {
-            NSLog("Failed to set AVAudioSession category")
-            print(error)
+            logger.error("Failed to set AVAudioSession category")
+            logger.error(error)
         }
     }
     
@@ -519,7 +523,7 @@ class AudioPlayer: NSObject {
         do {
             try AVAudioSession.sharedInstance().setActive(active)
         } catch {
-            NSLog("Failed to set audio session as active=\(active)")
+            logger.error("Failed to set audio session as active=\(active)")
         }
     }
     
@@ -650,11 +654,11 @@ class AudioPlayer: NSObject {
     public override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
         if context == &playerContext {
             if keyPath == #keyPath(AVPlayer.rate) {
-                NSLog("playerContext observer player rate")
+                logger.log("playerContext observer player rate")
                 self.setPlaybackRate(change?[.newKey] as? Float ?? 1.0, observed: true)
             } else if keyPath == #keyPath(AVPlayer.currentItem) {
                 NotificationCenter.default.post(name: NSNotification.Name(PlayerEvents.update.rawValue), object: nil)
-                NSLog("WARNING: Item ended")
+                logger.log("WARNING: Item ended")
             }
         } else {
             super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)

ios/App/Shared/player/AudioPlayerSleepTimer.swift

@@ -31,7 +31,7 @@ extension AudioPlayer {
     }
     
     public func setSleepTimer(secondsUntilSleep: Double) {
-        NSLog("SLEEP TIMER: Sleeping in \(secondsUntilSleep) seconds")
+        logger.log("SLEEP TIMER: Sleeping in \(secondsUntilSleep) seconds")
         self.removeSleepTimer()
         self.sleepTimeRemaining = secondsUntilSleep
         
@@ -48,7 +48,7 @@ extension AudioPlayer {
     }
     
     public func setChapterSleepTimer(stopAt: Double) {
-        NSLog("SLEEP TIMER: Scheduling for chapter end \(stopAt)")
+        logger.log("SLEEP TIMER: Scheduling for chapter end \(stopAt)")
         self.removeSleepTimer()
         
         // Schedule the observation time
@@ -124,7 +124,7 @@ extension AudioPlayer {
     }
     
     private func handleSleepEnd() {
-        NSLog("SLEEP TIMER: Pausing audio")
+        logger.log("SLEEP TIMER: Pausing audio")
         self.pause()
         self.removeSleepTimer()
     }

ios/App/Shared/player/PlayerProgress.swift

@@ -14,6 +14,8 @@ class PlayerProgress {
     
     private static let TIME_BETWEEN_SESSION_SYNC_IN_SECONDS = 10.0
     
+    private let logger = AppLogger(category: "PlayerProgress")
+    
     private init() {}
     
     
@@ -28,8 +30,8 @@ class PlayerProgress {
                 try await updateServerSessionFromLocalSession(session, rateLimitSync: !isStopping)
             }
         } catch {
-            debugPrint("Failed to syncFromPlayer")
-            debugPrint(error)
+            logger.error("Failed to syncFromPlayer")
+            logger.error(error)
         }
         await UIApplication.shared.endBackgroundTask(backgroundToken)
     }
@@ -39,8 +41,8 @@ class PlayerProgress {
         do {
             try await updateAllServerSessionFromLocalSession()
         } catch {
-            debugPrint("Failed to syncToServer")
-            debugPrint(error)
+            logger.error("Failed to syncToServer")
+            logger.error(error)
         }
         await UIApplication.shared.endBackgroundTask(backgroundToken)
     }
@@ -50,8 +52,8 @@ class PlayerProgress {
         do {
             try await updateLocalSessionFromServerMediaProgress()
         } catch {
-            debugPrint("Failed to syncFromServer")
-            debugPrint(error)
+            logger.error("Failed to syncFromServer")
+            logger.error(error)
         }
         await UIApplication.shared.endBackgroundTask(backgroundToken)
     }
@@ -96,7 +98,7 @@ class PlayerProgress {
 
         try localMediaProgress.updateFromPlaybackSession(session)
         
-        NSLog("Local progress saved to the database")
+        logger.log("Local progress saved to the database")
         
         // Send the local progress back to front-end
         NotificationCenter.default.post(name: NSNotification.Name(PlayerEvents.localProgress.rawValue), object: nil)
@@ -141,7 +143,7 @@ class PlayerProgress {
         session = session.freeze()
         
         guard safeToSync else { return }
-        NSLog("Sending sessionId(\(session.id)) to server with currentTime(\(session.currentTime))")
+        logger.log("Sending sessionId(\(session.id)) to server with currentTime(\(session.currentTime))")
         
         var success = false
         if session.isLocal {
@@ -161,25 +163,25 @@ class PlayerProgress {
     }
     
     private func updateLocalSessionFromServerMediaProgress() async throws {
-        NSLog("updateLocalSessionFromServerMediaProgress: Checking if local media progress was updated on server")
+        logger.log("updateLocalSessionFromServerMediaProgress: Checking if local media progress was updated on server")
         guard let session = try await Realm().objects(PlaybackSession.self).last(where: {
             $0.isActiveSession == true && $0.serverConnectionConfigId == Store.serverConfig?.id
         })?.freeze() else {
-            NSLog("updateLocalSessionFromServerMediaProgress: Failed to get session")
+            logger.log("updateLocalSessionFromServerMediaProgress: Failed to get session")
             return
         }
         
         // Fetch the current progress
         let progress = await ApiClient.getMediaProgress(libraryItemId: session.libraryItemId!, episodeId: session.episodeId)
         guard let progress = progress else {
-            NSLog("updateLocalSessionFromServerMediaProgress: No progress object")
+            logger.log("updateLocalSessionFromServerMediaProgress: No progress object")
             return
         }
         
         // Determine which session is newer
         let serverLastUpdate = progress.lastUpdate
         guard let localLastUpdate = session.updatedAt else {
-            NSLog("updateLocalSessionFromServerMediaProgress: No local session updatedAt")
+            logger.log("updateLocalSessionFromServerMediaProgress: No local session updatedAt")
             return
         }
         let serverCurrentTime = progress.currentTime
@@ -190,16 +192,16 @@ class PlayerProgress {
         
         // Update the session, if needed
         if serverIsNewerThanLocal && currentTimeIsDifferent {
-            NSLog("updateLocalSessionFromServerMediaProgress: Server has newer time than local serverLastUpdate=\(serverLastUpdate) localLastUpdate=\(localLastUpdate)")
+            logger.log("updateLocalSessionFromServerMediaProgress: Server has newer time than local serverLastUpdate=\(serverLastUpdate) localLastUpdate=\(localLastUpdate)")
             guard let session = session.thaw() else { return }
             try session.update {
                 session.currentTime = serverCurrentTime
                 session.updatedAt = serverLastUpdate
             }
-            NSLog("updateLocalSessionFromServerMediaProgress: Updated session currentTime newCurrentTime=\(serverCurrentTime) previousCurrentTime=\(localCurrentTime)")
+            logger.log("updateLocalSessionFromServerMediaProgress: Updated session currentTime newCurrentTime=\(serverCurrentTime) previousCurrentTime=\(localCurrentTime)")
             PlayerHandler.seek(amount: session.currentTime)
         } else {
-            NSLog("updateLocalSessionFromServerMediaProgress: Local session does not need updating; local has latest progress")
+            logger.log("updateLocalSessionFromServerMediaProgress: Local session does not need updating; local has latest progress")
         }
     }
     

ios/App/Shared/util/ApiClient.swift

@@ -9,6 +9,8 @@ import Foundation
 import Alamofire
 
 class ApiClient {
+    private static let logger = AppLogger(category: "ApiClient")
+    
     public static func getData(from url: URL, completion: @escaping (UIImage?) -> Void) {
         URLSession.shared.dataTask(with: url, completionHandler: {(data, response, error) in
             if let data = data {
@@ -19,7 +21,7 @@ class ApiClient {
     
     public static func postResource<T: Decodable>(endpoint: String, parameters: [String: Any], decodable: T.Type = T.self, callback: ((_ param: T) -> Void)?) {
         if (Store.serverConfig == nil) {
-            NSLog("Server config not set")
+            logger.error("Server config not set")
             return
         }
         
@@ -32,7 +34,7 @@ class ApiClient {
             case .success(let obj):
                 callback?(obj)
             case .failure(let error):
-                NSLog("api request to \(endpoint) failed")
+                logger.error("api request to \(endpoint) failed")
                 print(error)
             }
         }
@@ -40,7 +42,7 @@ class ApiClient {
     
     public static func postResource<T: Encodable, U: Decodable>(endpoint: String, parameters: T, decodable: U.Type = U.self, callback: ((_ param: U) -> Void)?) {
         if (Store.serverConfig == nil) {
-            NSLog("Server config not set")
+            logger.error("Server config not set")
             return
         }
         
@@ -53,7 +55,7 @@ class ApiClient {
             case .success(let obj):
                 callback?(obj)
             case .failure(let error):
-                NSLog("api request to \(endpoint) failed")
+                logger.error("api request to \(endpoint) failed")
                 print(error)
             }
         }
@@ -69,7 +71,7 @@ class ApiClient {
     
     public static func postResource<T:Encodable>(endpoint: String, parameters: T, callback: ((_ success: Bool) -> Void)?) {
         if (Store.serverConfig == nil) {
-            NSLog("Server config not set")
+            logger.error("Server config not set")
             callback?(false)
             return
         }
@@ -83,7 +85,7 @@ class ApiClient {
             case .success(_):
                 callback?(true)
             case .failure(let error):
-                NSLog("api request to \(endpoint) failed")
+                logger.error("api request to \(endpoint) failed")
                 print(error)
                 
                 callback?(false)
@@ -93,7 +95,7 @@ class ApiClient {
     
     public static func patchResource<T: Encodable>(endpoint: String, parameters: T, callback: ((_ success: Bool) -> Void)?) {
         if (Store.serverConfig == nil) {
-            NSLog("Server config not set")
+            logger.error("Server config not set")
             callback?(false)
             return
         }
@@ -107,7 +109,7 @@ class ApiClient {
             case .success(_):
                 callback?(true)
             case .failure(let error):
-                NSLog("api request to \(endpoint) failed")
+                logger.error("api request to \(endpoint) failed")
                 print(error)
                 callback?(false)
             }
@@ -124,7 +126,7 @@ class ApiClient {
     
     public static func getResource<T: Decodable>(endpoint: String, decodable: T.Type = T.self, callback: ((_ param: T?) -> Void)?) {
         if (Store.serverConfig == nil) {
-            NSLog("Server config not set")
+            logger.error("Server config not set")
             callback?(nil)
             return
         }
@@ -138,7 +140,7 @@ class ApiClient {
                 case .success(let obj):
                     callback?(obj)
                 case .failure(let error):
-                    NSLog("api request to \(endpoint) failed")
+                    logger.error("api request to \(endpoint) failed")
                     print(error)
             }
         }
@@ -193,10 +195,10 @@ class ApiClient {
         
         if ( !localMediaProgressList.isEmpty ) {
             let payload = LocalMediaProgressSyncPayload(localMediaProgress: localMediaProgressList)
-            NSLog("Sending sync local progress request with \(localMediaProgressList.count) progress items")
+            logger.log("Sending sync local progress request with \(localMediaProgressList.count) progress items")
             postResource(endpoint: "api/me/sync-local-progress", parameters: payload, decodable: MediaProgressSyncResponsePayload.self) { response in
                 let resultsPayload = LocalMediaProgressSyncResultsPayload(numLocalMediaProgressForServer: localMediaProgressList.count, numServerProgressUpdates: response.numServerProgressUpdates, numLocalProgressUpdates: response.localProgressUpdates?.count)
-                NSLog("Media Progress Sync | \(String(describing: try? resultsPayload.asDictionary()))")
+                logger.log("Media Progress Sync | \(String(describing: try? resultsPayload.asDictionary()))")
                 
                 if let updates = response.localProgressUpdates {
                     for update in updates {
@@ -212,13 +214,13 @@ class ApiClient {
                 callback(resultsPayload)
             }
         } else {
-            NSLog("No local media progress to sync")
+            logger.log("No local media progress to sync")
             callback(LocalMediaProgressSyncResultsPayload(numLocalMediaProgressForServer: 0, numServerProgressUpdates: 0, numLocalProgressUpdates: 0))
         }
     }
     
     public static func updateMediaProgress<T:Encodable>(libraryItemId: String, episodeId: String?, payload: T, callback: @escaping () -> Void) {
-        NSLog("updateMediaProgress \(libraryItemId) \(episodeId ?? "NIL") \(payload)")
+        logger.log("updateMediaProgress \(libraryItemId) \(episodeId ?? "NIL") \(payload)")
         let endpoint = episodeId?.isEmpty ?? true ? "api/me/progress/\(libraryItemId)" : "api/me/progress/\(libraryItemId)/\(episodeId ?? "")"
         patchResource(endpoint: endpoint, parameters: payload) { success in
             callback()
@@ -226,7 +228,7 @@ class ApiClient {
     }
     
     public static func getMediaProgress(libraryItemId: String, episodeId: String?) async -> MediaProgress? {
-        NSLog("getMediaProgress \(libraryItemId) \(episodeId ?? "NIL")")
+        logger.log("getMediaProgress \(libraryItemId) \(episodeId ?? "NIL")")
         let endpoint = episodeId?.isEmpty ?? true ? "api/me/progress/\(libraryItemId)" : "api/me/progress/\(libraryItemId)/\(episodeId ?? "")"
         return await getResource(endpoint: endpoint, decodable: MediaProgress.self)
     }

ios/App/Shared/util/Database.swift

@@ -12,6 +12,8 @@ class Database {
     public static var shared = {
         return Database()
     }()
+    
+    private let logger = AppLogger(category: "Database")
 
     private init() {}
     
@@ -30,7 +32,7 @@ class Database {
                     existing.token = config.token
                 }
             } catch {
-                NSLog("failed to update server config")
+                logger.error("failed to update server config")
                 debugPrint(error)
             }
             
@@ -51,7 +53,7 @@ class Database {
                     realm.add(config)
                 }
             } catch(let exception) {
-                NSLog("failed to save server config")
+                logger.error("failed to save server config")
                 debugPrint(exception)
             }
             
@@ -70,7 +72,7 @@ class Database {
                 }
             }
         } catch(let exception) {
-            NSLog("failed to delete server config")
+            logger.error("failed to delete server config")
             debugPrint(exception)
         }
     }
@@ -101,7 +103,7 @@ class Database {
                 }
             }
         } catch(let exception) {
-            NSLog("failed to save server config active index")
+            logger.error("failed to save server config active index")
             debugPrint(exception)
         }
     }
@@ -121,7 +123,7 @@ class Database {
                 realm.add(deviceSettings)
             }
         } catch {
-            NSLog("failed to save device settings")
+            logger.error("failed to save device settings")
         }
     }
     

ios/App/Shared/util/Extensions.swift

@@ -59,7 +59,7 @@ extension CAPPluginCall {
             let json = try JSONSerialization.data(withJSONObject: value)
             return try JSONDecoder().decode(type, from: json)
         } catch {
-            NSLog("Failed to get json for \(key)")
+            AppLogger().error("Failed to get json for \(key)")
             debugPrint(error)
             return nil
         }

ios/App/Shared/util/Logger.swift

@@ -0,0 +1,72 @@
+//
+//  AppLogger.swift
+//  AppLogger
+//
+//  Created by Fernando Fernandes on 29.06.20.
+//
+
+import Foundation
+import os
+
+/// Logs app info by using the newest Swift unified logging APIs.
+///
+/// Reference:
+///  - [Explore logging in Swift (WWDC20)](https://developer.apple.com/wwdc20/10168)
+///  - [Unified Logging](https://developer.apple.com/documentation/os/logging)
+///  - [OSLog](https://developer.apple.com/documentation/os/oslog)
+///  - [Logger](https://developer.apple.com/documentation/os/logger)
+public struct AppLogger {
+
+    // MARK: - Properties
+
+    /// Default values used by the `AppLogger`.
+    public struct Defaults {
+        public static let subsystem = Bundle.main.bundleIdentifier ?? "ABS"
+        public static let category = "default"
+        public static let isPrivate = false
+    }
+
+    // MARK: - Private Properties
+
+    private let logger: Logger
+
+    // MARK: - Lifecycle
+
+    /// Creates an `AppLogger` instance.
+    ///
+    /// - Parameters:
+    ///   - subsystem: `String`. Organizes large topic areas within the app or apps. For example, you might define
+    ///   a subsystem for each process that you create. The default is `Bundle.main.bundleIdentifier ?? "AppLogger"`.
+    ///   - category: `String`. Within a `subsystem`, you define categories to further distinguish parts of that
+    ///   subsystem. For example, if you used a single subsystem for your app, you might create separate categories for
+    ///   model code and user-interface code. In a game, you might use categories to distinguish between physics, AI,
+    ///   world simulation, and rendering. The default is `default`.
+    public init(subsystem: String = Defaults.subsystem, category: String = Defaults.category) {
+        self.logger = Logger(subsystem: subsystem, category: category)
+    }
+}
+
+// MARK: - Interface
+
+public extension AppLogger {
+    
+    func log(_ information: String, isPrivate: Bool = Defaults.isPrivate) {
+        if isPrivate {
+            logger.log("\(information, privacy: .private)")
+        } else {
+            logger.log("\(information, privacy: .public)")
+        }
+    }
+    
+    func error(_ information: String, isPrivate: Bool = Defaults.isPrivate) {
+        if isPrivate {
+            logger.error("\(information, privacy: .private)")
+        } else {
+            logger.error("\(information, privacy: .public)")
+        }
+    }
+    
+    func error(_ error: Error) {
+        logger.error("\(String(describing: error))")
+    }
+}