Decouple the audio attachment player from the video attachment adapter.

// FREEBIE

Signal/src/Models/TSMessageAdapaters/TSVideoAttachmentAdapter.h

@@ -2,6 +2,7 @@
 //  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
 //
 
+#import "OWSAudioAttachmentPlayer.h"
 #import "OWSMessageEditing.h"
 #import "OWSMessageMediaAdapter.h"
 #import <JSQMessagesViewController/JSQVideoMediaItem.h>
@@ -10,22 +11,16 @@ NS_ASSUME_NONNULL_BEGIN
 
 @class TSAttachmentStream;
 
-@interface TSVideoAttachmentAdapter : JSQVideoMediaItem <OWSMessageEditing, OWSMessageMediaAdapter>
+@interface TSVideoAttachmentAdapter
+    : JSQVideoMediaItem <OWSMessageEditing, OWSMessageMediaAdapter, OWSAudioAttachmentPlayerDelegate>
 
 @property NSString *attachmentId;
 @property (nonatomic, strong) NSString *contentType;
-@property (nonatomic) BOOL isAudioPlaying;
-@property (nonatomic) BOOL isPaused;
 
 - (instancetype)initWithAttachment:(TSAttachmentStream *)attachment incoming:(BOOL)incoming;
 
 - (BOOL)isAudio;
 - (BOOL)isVideo;
-- (void)setAudioProgressFromFloat:(float)progress;
-- (void)setAudioIconToPlay;
-- (void)setAudioIconToPause;
-- (void)setDurationOfAudio:(NSTimeInterval)duration;
-- (void)resetAudioDuration;
 
 @end
 

Signal/src/Models/TSMessageAdapaters/TSVideoAttachmentAdapter.m

@@ -28,6 +28,8 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, nullable) UILabel *durationLabel;
 @property (nonatomic) BOOL incoming;
 @property (nonatomic, nullable) AttachmentUploadView *attachmentUploadView;
+@property (nonatomic) BOOL isAudioPlaying;
+@property (nonatomic) BOOL isPaused;
 
 @end
 
@@ -96,16 +98,6 @@ NS_ASSUME_NONNULL_BEGIN
     });
 }
 
-- (void)resetAudioDuration {
-    NSError *err;
-    AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:_attachment.mediaURL error:&err];
-    _durationLabel.text   = [self formatDuration:player.duration];
-}
-
-- (void)setDurationOfAudio:(NSTimeInterval)duration {
-    _durationLabel.text = [self formatDuration:duration];
-}
-
 - (void)setAudioIconToPlay {
     [_audioPlayPauseButton
         setBackgroundImage:[UIImage imageNamed:(_incoming ? @"audio_play_button_blue" : @"audio_play_button")]

Signal/src/ViewControllers/MessagesViewController.m

@@ -1789,7 +1789,8 @@ typedef enum : NSUInteger {
                             }
                         } else if ([messageMedia isAudio]) {
                             if (self.audioAttachmentPlayer) {
-                                if (self.audioAttachmentPlayer.mediaAdapter == messageMedia) {
+                                // Is this player associated with this media adapter?
+                                if (self.audioAttachmentPlayer.owner == messageMedia) {
                                     // Tap to pause & unpause.
                                     [self.audioAttachmentPlayer togglePlayState];
                                     return;
@@ -1800,6 +1801,8 @@ typedef enum : NSUInteger {
                             self.audioAttachmentPlayer =
                                 [[OWSAudioAttachmentPlayer alloc] initWithMediaAdapter:messageMedia
                                                                     databaseConnection:self.uiDatabaseConnection];
+                            // Associate the player with this media adapter.
+                            self.audioAttachmentPlayer.owner = messageMedia;
                             [self.audioAttachmentPlayer play];
                         }
                     }

Signal/src/ViewControllers/OWSAudioAttachmentPlayer.h

@@ -9,13 +9,39 @@ NS_ASSUME_NONNULL_BEGIN
 @class TSVideoAttachmentAdapter;
 @class YapDatabaseConnection;
 
+@protocol OWSAudioAttachmentPlayerDelegate <NSObject>
+
+- (BOOL)isAudioPlaying;
+- (void)setIsAudioPlaying:(BOOL)isAudioPlaying;
+
+- (BOOL)isPaused;
+- (void)setIsPaused:(BOOL)isPaused;
+
+- (void)setAudioProgressFromFloat:(float)progress;
+- (void)setAudioIconToPlay;
+- (void)setAudioIconToPause;
+
+@end
+
+#pragma mark -
+
 @interface OWSAudioAttachmentPlayer : NSObject <AVAudioPlayerDelegate>
 
-@property (nonatomic, readonly) TSVideoAttachmentAdapter *mediaAdapter;
+@property (nonatomic, readonly, weak) id<OWSAudioAttachmentPlayerDelegate> delegate;
+
+// This property can be used to associate instances of the player with view
+// or model objects.
+@property (nonatomic, weak) id owner;
 
+// A convenience initializer for MessagesViewController.
+//
+// It assumes the delegate (e.g. view) for this player will be the adapter.
 - (instancetype)initWithMediaAdapter:(TSVideoAttachmentAdapter *)mediaAdapter
                   databaseConnection:(YapDatabaseConnection *)databaseConnection;
 
+// An generic initializer.
+- (instancetype)initWithMediaUrl:(NSURL *)mediaUrl delegate:(id<OWSAudioAttachmentPlayerDelegate>)delegate;
+
 - (void)play;
 - (void)pause;
 - (void)stop;

Signal/src/ViewControllers/OWSAudioAttachmentPlayer.m

@@ -13,7 +13,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface OWSAudioAttachmentPlayer ()
 
-@property (nonatomic) TSAttachmentStream *attachmentStream;
+@property (nonatomic, readonly) NSURL *mediaUrl;
 
 @property (nonatomic, nullable) AVAudioPlayer *audioPlayer;
 @property (nonatomic, nullable) NSTimer *audioPlayerPoller;
@@ -24,31 +24,49 @@ NS_ASSUME_NONNULL_BEGIN
 
 @implementation OWSAudioAttachmentPlayer
 
-- (instancetype)initWithMediaAdapter:(TSVideoAttachmentAdapter *)mediaAdapter
++ (NSURL *)mediaUrlForMediaAdapter:(TSVideoAttachmentAdapter *)mediaAdapter
-                  databaseConnection:(YapDatabaseConnection *)databaseConnection
+                databaseConnection:(YapDatabaseConnection *)databaseConnection
 {
-    self = [super init];
-    if (!self) {
-        return self;
-    }
-
     OWSAssert(mediaAdapter);
     OWSAssert([mediaAdapter isAudio]);
     OWSAssert(mediaAdapter.attachmentId);
     OWSAssert(databaseConnection);
 
-    _mediaAdapter = mediaAdapter;
-
     __block TSAttachment *attachment = nil;
     [databaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         attachment = [TSAttachment fetchObjectWithUniqueID:mediaAdapter.attachmentId transaction:transaction];
     }];
     OWSAssert(attachment);
 
+    TSAttachmentStream *attachmentStream = nil;
     if ([attachment isKindOfClass:[TSAttachmentStream class]]) {
-        self.attachmentStream = (TSAttachmentStream *)attachment;
+        attachmentStream = (TSAttachmentStream *)attachment;
     }
-    OWSAssert(self.attachmentStream);
+    OWSAssert(attachmentStream);
+
+    return attachmentStream.mediaURL;
+}
+
+- (instancetype)initWithMediaAdapter:(TSVideoAttachmentAdapter *)mediaAdapter
+                  databaseConnection:(YapDatabaseConnection *)databaseConnection
+{
+    return [self initWithMediaUrl:[OWSAudioAttachmentPlayer mediaUrlForMediaAdapter:mediaAdapter
+                                                                 databaseConnection:databaseConnection]
+                         delegate:mediaAdapter];
+}
+
+- (instancetype)initWithMediaUrl:(NSURL *)mediaUrl delegate:(id<OWSAudioAttachmentPlayerDelegate>)delegate
+{
+    self = [super init];
+    if (!self) {
+        return self;
+    }
+
+    OWSAssert(mediaUrl);
+    OWSAssert(delegate);
+
+    _delegate = delegate;
+    _mediaUrl = mediaUrl;
 
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(applicationDidEnterBackground:)
@@ -74,20 +92,21 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)play
 {
-    OWSAssert(self.attachmentStream);
+    OWSAssert([NSThread isMainThread]);
-    OWSAssert(![self.mediaAdapter isAudioPlaying]);
+    OWSAssert(self.mediaUrl);
+    OWSAssert(![self.delegate isAudioPlaying]);
 
     [ViewControllerUtils setAudioIgnoresHardwareMuteSwitch:YES];
 
     [self.audioPlayerPoller invalidate];
 
-    self.mediaAdapter.isAudioPlaying = YES;
+    self.delegate.isAudioPlaying = YES;
-    self.mediaAdapter.isPaused = NO;
+    self.delegate.isPaused = NO;
-    [self.mediaAdapter setAudioIconToPause];
+    [self.delegate setAudioIconToPause];
 
     if (!self.audioPlayer) {
         NSError *error;
-        self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:self.attachmentStream.mediaURL error:&error];
+        self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:self.mediaUrl error:&error];
         if (error) {
             DDLogError(@"%@ error: %@", self.tag, error);
             [self stop];
@@ -107,35 +126,34 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)pause
 {
-    OWSAssert(self.attachmentStream);
+    OWSAssert([NSThread isMainThread]);
 
-    self.mediaAdapter.isAudioPlaying = NO;
+    self.delegate.isAudioPlaying = NO;
-    self.mediaAdapter.isPaused = YES;
+    self.delegate.isPaused = YES;
     [self.audioPlayer pause];
     [self.audioPlayerPoller invalidate];
     double current = [self.audioPlayer currentTime] / [self.audioPlayer duration];
-    [self.mediaAdapter setAudioProgressFromFloat:(float)current];
+    [self.delegate setAudioProgressFromFloat:(float)current];
-    [self.mediaAdapter setAudioIconToPlay];
+    [self.delegate setAudioIconToPlay];
 }
 
 - (void)stop
 {
-    OWSAssert(self.attachmentStream);
+    OWSAssert([NSThread isMainThread]);
 
     [self.audioPlayer pause];
     [self.audioPlayerPoller invalidate];
-    [self.mediaAdapter setAudioProgressFromFloat:0];
+    [self.delegate setAudioProgressFromFloat:0];
-    [self.mediaAdapter setDurationOfAudio:self.audioPlayer.duration];
+    [self.delegate setAudioIconToPlay];
-    [self.mediaAdapter setAudioIconToPlay];
+    self.delegate.isAudioPlaying = NO;
-    self.mediaAdapter.isAudioPlaying = NO;
+    self.delegate.isPaused = NO;
-    self.mediaAdapter.isPaused = NO;
 }
 
 - (void)togglePlayState
 {
-    OWSAssert(self.attachmentStream);
+    OWSAssert([NSThread isMainThread]);
 
-    if (self.mediaAdapter.isAudioPlaying) {
+    if (self.delegate.isAudioPlaying) {
         [self pause];
     } else {
         [self play];
@@ -146,17 +164,19 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)audioPlayerUpdated:(NSTimer *)timer
 {
+    OWSAssert([NSThread isMainThread]);
+
     OWSAssert(self.audioPlayer);
     OWSAssert(self.audioPlayerPoller);
 
     double current = [self.audioPlayer currentTime] / [self.audioPlayer duration];
-    double interval = [self.audioPlayer duration] - [self.audioPlayer currentTime];
+    [self.delegate setAudioProgressFromFloat:(float)current];
-    [self.mediaAdapter setDurationOfAudio:interval];
-    [self.mediaAdapter setAudioProgressFromFloat:(float)current];
 }
 
 - (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
 {
+    OWSAssert([NSThread isMainThread]);
+
     [self stop];
 }