Remove appForegroundTime property

Signal/AppLaunch/MainAppContext.swift

@@ -11,14 +11,11 @@ class MainAppContext: NSObject, AppContext {
 
     let appLaunchTime: Date
 
-    private(set) var appForegroundTime: Date
-
     override init() {
         _reportedApplicationState = AtomicValue(.inactive, lock: .init())
 
         let launchDate = Date()
         appLaunchTime = launchDate
-        appForegroundTime = launchDate
         _mainApplicationStateOnLaunch = UIApplication.shared.applicationState
 
         super.init()
@@ -68,7 +65,6 @@ class MainAppContext: NSObject, AppContext {
         AssertIsOnMainThread()
 
         self.reportedApplicationState = .inactive
-        self.appForegroundTime = Date()
 
         BenchManager.bench(title: "Slow WillEnterForeground", logIfLongerThan: 0.2, logInProduction: true) {
             NotificationCenter.default.post(name: .OWSApplicationWillEnterForeground, object: nil)

Signal/src/ViewControllers/HomeView/Stories/Context View/StoryPageViewController.swift

@@ -183,28 +183,33 @@ class StoryPageViewController: UIPageViewController {
     private struct MuteStatus {
         let isMuted: Bool
         let shouldInitialRingerStateSetMuteState: Bool
-        let appForegroundTime: Date
     }
 
     // Once unmuted, stays that way until the app is backgrounded.
-    private static var muteStatus: MuteStatus?
+    private static var muteStatus: MuteStatus? {
+        didSet {
+            if muteStatus != nil, muteStatusObserver == nil {
+                muteStatusObserver = NotificationCenter.default.addObserver(
+                    forName: UIApplication.willEnterForegroundNotification,
+                    object: nil,
+                    queue: nil,
+                    using: { _ in muteStatus = nil },
+                )
+            }
+        }
+    }
+
+    private static var muteStatusObserver: (any NSObjectProtocol)?
 
     private var isMuted: Bool {
         get {
-            let appForegroundTime = CurrentAppContext().appForegroundTime
-            if
-                let muteStatus = Self.muteStatus,
-                // Mute status is only valid for one foregroundind session,
-                // dedupe by timestamp.
-                muteStatus.appForegroundTime == appForegroundTime
-            {
+            if let muteStatus = Self.muteStatus {
                 return muteStatus.isMuted
             }
             // Start muted, but let the ringer change the setting.
             let muteStatus = MuteStatus(
                 isMuted: true,
                 shouldInitialRingerStateSetMuteState: true,
-                appForegroundTime: CurrentAppContext().appForegroundTime
             )
             Self.muteStatus = muteStatus
             return muteStatus.isMuted
@@ -213,7 +218,6 @@ class StoryPageViewController: UIPageViewController {
             Self.muteStatus = MuteStatus(
                 isMuted: newValue,
                 shouldInitialRingerStateSetMuteState: false,
-                appForegroundTime: CurrentAppContext().appForegroundTime
             )
             viewControllers?.forEach {
                 ($0 as? StoryContextViewController)?.updateMuteState()

SignalNSE/NSEContext.swift

@@ -19,8 +19,6 @@ class NSEContext: NSObject, AppContext {
     func canPresentNotifications() -> Bool { true }
 
     let appLaunchTime = Date()
-    // In NSE foreground and launch are the same.
-    var appForegroundTime: Date { return appLaunchTime }
 
     func appDocumentDirectoryPath() -> String {
         guard let documentDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).last else {

SignalServiceKit/TestUtils/TestAppContext.swift

@@ -24,7 +24,6 @@ public class TestAppContext: NSObject, AppContext {
 
     public var mainWindow: UIWindow?
     public let appLaunchTime: Date
-    public let appForegroundTime: Date
 
     public override init() {
         // Avoid using OWSTemporaryDirectory(); it can consult the current app context.
@@ -41,7 +40,6 @@ public class TestAppContext: NSObject, AppContext {
         self.internalAppUserDefaults = UserDefaults()
         let launchDate = Date()
         self.appLaunchTime = launchDate
-        self.appForegroundTime = launchDate
 
         super.init()
     }

SignalServiceKit/Util/AppContext.swift

@@ -84,9 +84,6 @@ public protocol AppContext {
 
     var appLaunchTime: Date { get }
 
-    /// Will be updated every time the app is foregrounded.
-    var appForegroundTime: Date { get }
-
     func appDocumentDirectoryPath() -> String
 
     func appSharedDataDirectoryPath() -> String

SignalShareExtension/ShareAppExtensionContext.swift

@@ -16,8 +16,6 @@ final class ShareAppExtensionContext: NSObject {
 
     let appLaunchTime = Date()
 
-    let appForegroundTime = Date()
-
     private var notificationCenterObservers = [NSObjectProtocol]()
 
     static private let isRTL: Bool = {