Respect system alert volume for notifications while in app

// FREEBIE

Signal/src/environment/NotificationsManager.m

@@ -239,8 +239,9 @@
         } else {
             if (shouldPlaySound && [Environment.preferences soundInForeground]) {
                 OWSSound sound = [OWSSounds notificationSoundForThread:thread];
-                self.audioPlayer = [OWSSounds audioPlayerForSound:sound];
+                SystemSoundID soundId = [OWSSounds systemSoundIDForSound:sound quiet:YES];
-                [self.audioPlayer playAsForegroundAlert];
+                // Vibrate, respect silent switch, respect "Alert" volume, not media volume.
+                AudioServicesPlayAlertSound(soundId);
             }
         }
     });
@@ -345,8 +346,9 @@
         } else {
             if (shouldPlaySound && [Environment.preferences soundInForeground]) {
                 OWSSound sound = [OWSSounds notificationSoundForThread:thread];
-                self.audioPlayer = [OWSSounds audioPlayerForSound:sound];
+                SystemSoundID soundId = [OWSSounds systemSoundIDForSound:sound quiet:YES];
-                [self.audioPlayer playAsForegroundAlert];
+                // Vibrate, respect silent switch, respect "Alert" volume, not media volume.
+                AudioServicesPlayAlertSound(soundId);
             }
         }
     });

SignalMessaging/environment/OWSSounds.h

@@ -2,6 +2,8 @@
 //  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
+#import <AudioToolbox/AudioServices.h>
+
 NS_ASSUME_NONNULL_BEGIN
 
 typedef NS_ENUM(NSUInteger, OWSSound) {
@@ -57,6 +59,7 @@ typedef NS_ENUM(NSUInteger, OWSSound) {
 + (void)setGlobalNotificationSound:(OWSSound)sound transaction:(YapDatabaseReadWriteTransaction *)transaction;
 
 + (OWSSound)notificationSoundForThread:(TSThread *)thread;
++ (SystemSoundID)systemSoundIDForSound:(OWSSound)sound quiet:(BOOL)quiet;
 + (void)setNotificationSound:(OWSSound)sound forThread:(TSThread *)thread;
 
 #pragma mark - AudioPlayer

SignalMessaging/environment/OWSSounds.m

@@ -16,6 +16,7 @@ NSString *const kOWSSoundsStorageGlobalNotificationKey = @"kOWSSoundsStorageGlob
 @interface OWSSounds ()
 
 @property (nonatomic, readonly) YapDatabaseConnection *dbConnection;
+@property (nonatomic, readonly) NSMutableDictionary<NSString *, NSNumber *> *cachedSoundIDs;
 
 @end
 
@@ -51,6 +52,7 @@ NSString *const kOWSSoundsStorageGlobalNotificationKey = @"kOWSSoundsStorageGlob
     OWSAssert(primaryStorage);
 
     _dbConnection = primaryStorage.newDatabaseConnection;
+    _cachedSoundIDs = [NSMutableDictionary new];
 
     OWSSingletonAssert();
 
@@ -207,6 +209,33 @@ NSString *const kOWSSoundsStorageGlobalNotificationKey = @"kOWSSoundsStorageGlob
     return url;
 }
 
++ (SystemSoundID)systemSoundIDForSound:(OWSSound)sound quiet:(BOOL)quiet
+{
+    return [self.sharedManager systemSoundIDForSound:(OWSSound)sound quiet:quiet];
+}
+
+- (SystemSoundID)systemSoundIDForSound:(OWSSound)sound quiet:(BOOL)quiet
+{
+    NSString *cacheKey = [NSString stringWithFormat:@"%lu:%d", (unsigned long)sound, quiet];
+    NSNumber *cachedSoundId = self.cachedSoundIDs[cacheKey];
+
+    if (cachedSoundId) {
+        return (SystemSoundID)cachedSoundId.intValue;
+    }
+
+    NSURL *soundURL = [self.class soundURLForSound:sound quiet:quiet];
+
+    DDLogVerbose(@"%@ creating system sound for %@", self.logTag, soundURL.lastPathComponent);
+    SystemSoundID newSoundID;
+    OSStatus status = AudioServicesCreateSystemSoundID((__bridge CFURLRef _Nonnull)(soundURL), &newSoundID);
+    OWSAssert(status == 0);
+    OWSAssert(newSoundID);
+
+    self.cachedSoundIDs[cacheKey] = @(newSoundID);
+
+    return newSoundID;
+}
+
 #pragma mark - Notifications
 
 + (OWSSound)defaultNotificationSound

SignalMessaging/utils/OWSAudioPlayer.h

@@ -38,9 +38,6 @@ typedef NS_ENUM(NSInteger, AudioPlaybackState) {
 // respects silent switch
 - (void)playWithCurrentAudioCategory;
 
-// respects silent switch, mixes with others
-- (void)playAsForegroundAlert;
-
 // will ensure sound is audible, even if silent switch is enabled
 - (void)playWithPlaybackAudioCategory;
 

SignalMessaging/utils/OWSAudioPlayer.m

@@ -104,15 +104,6 @@ NS_ASSUME_NONNULL_BEGIN
     [self play];
 }
 
-- (void)playAsForegroundAlert
-{
-    OWSAssertIsOnMainThread();
-    [OWSAudioSession.shared startAmbientAudioActivity:self.audioActivity];
-
-    AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
-    [self play];
-}
-
 - (void)play
 {
     OWSAssertIsOnMainThread();