RmxAudioPlayer.m

#import "RmxAudioPlayer.h"
#import "AVBidirectionalQueuePlayer.h"

static char kAvQueuePlayerContext;
static char kAvQueuePlayerRateContext;
static char kPlayerItemStatusContext;
static char kPlayerItemDurationContext;
static char kPlayerItemTimeRangesContext;

@interface RmxAudioPlayer() {
    id _playbackTimeObserver;
    BOOL _wasPlayingInterrupted;
    BOOL _commandCenterRegistered;
    BOOL _resetStreamOnPause;
    NSMutableDictionary* _updatedNowPlayingInfo;
    float _rate;
    float _volume;
    BOOL _isReplacingItems;
    BOOL _isWaitingToStartPlayback;
}
@property () NSString* statusCallbackId;
@property (nonatomic, strong) AVBidirectionalQueuePlayer* avQueuePlayer;
@property (nonatomic) NSMutableArray* currentItems;
//@property (nonatomic) NSUInteger currentIndex;
@property () float rate;
@property () float volume;
@property () BOOL loop;
@property (nonatomic) BOOL isAtEnd;
@property (nonatomic) BOOL isAtBeginning;
@property (nonatomic) BOOL isPlaying;
@property (nonatomic) float queuePosition;
@end

@implementation RmxAudioPlayer

- (void) pluginInitialize
{
    _playbackTimeObserver = nil;
    _wasPlayingInterrupted = NO;
    _commandCenterRegistered = NO;
    _updatedNowPlayingInfo = nil;
    _resetStreamOnPause = YES;
    _isReplacingItems = NO;
    _isWaitingToStartPlayback = NO;
    self.rate = 1.0f;
    self.volume = 1.0f;
    self.loop = false;

    [self activateAudioSession];
    [self observeLifeCycle];
}


#pragma mark - Cordova interface

/**
 *
 * Cordova interface
 *
 * These are basically just passing through to the core functionality of the queue and this player.
 *
 * These functions don't really do anything interesting by themselves.
 *
 *
 *
 *
 *
 */
- (void) initialize:(CDVInvokedUrlCommand*) command
{
    NSLog(@"RmxAudioPlayer.execute=initialize");
    self.statusCallbackId = command.callbackId;
    [self onStatus:RMXSTATUS_REGISTER trackId:@"INIT" param:nil];
}

- (void) setOptions:(CDVInvokedUrlCommand*) command {
    NSDictionary* options = [command.arguments objectAtIndex:0];
    if (options == nil) {
        options = @{};
    }
    NSLog(@"RmxAudioPlayer.execute=setOptions, %@", options);
    _resetStreamOnPause = [options[@"resetStreamOnPause"] boolValue];
    // We don't do anything with these yet.
    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDictionary:options];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}

- (void) setPlaylistItems:(CDVInvokedUrlCommand *) command {
    NSMutableArray* items = [command.arguments objectAtIndex:0];
    NSDictionary* options = [command.arguments objectAtIndex:1];

    if (options == nil) {
        options = @{};
    }

    NSLog(@"RmxAudioPlayer.execute=setPlaylistItems, %@, %@", options, items);

    float seekToPosition = 0.0f;
    BOOL retainPosition = options[@"retainPosition"] != nil ? [options[@"retainPosition"] boolValue] : NO;
    float playFromPosition = options[@"playFromPosition"] != nil ? [options[@"playFromPosition"] floatValue] : 0.0f;
    NSString* playFromId = options[@"playFromId"] != nil ? [options[@"playFromId"] stringValue] : nil;
    BOOL startPaused = options[@"startPaused"] != nil ? [options[@"startPaused"] boolValue] : YES;

    if (retainPosition) {
        seekToPosition = [self getTrackCurrentTime:nil];
        if (playFromPosition > 0.0f) {
            seekToPosition = playFromPosition;
        }
    }

    NSDictionary* result = [self findTrackById:playFromId];
    NSInteger idx = [(NSNumber*)result[@"index"] integerValue];
    // AudioTrack* track = result[@"track"];

    if ([self avQueuePlayer].itemsForPlayer.count > 0) {
        if (idx >= 0) {
            [self avQueuePlayer].currentIndex = idx;
        }
    }

    [self.commandDelegate runInBackground:^{
        // This will wait for the AVPlayerItemStatusReadyToPlay status change, and then trigger playback.
        _isWaitingToStartPlayback = !startPaused;
        if (_isWaitingToStartPlayback) {
            NSLog(@"RmxAudioPlayer[setPlaylistItems] will wait for ready event to begin playback");
        }

        [self insertOrReplaceTracks:items replace:YES startPosition:seekToPosition];
        if (_isWaitingToStartPlayback) {
            [self playCommand:NO]; // but we will try to preempt it to avoid the button blinking paused.
        }

        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
        [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
    }];
}

- (void) addItem:(CDVInvokedUrlCommand *) command {
    NSMutableDictionary* item = [command.arguments objectAtIndex:0];

    NSLog(@"RmxAudioPlayer.execute=addItem, %@", item);

    AudioTrack* newTrack = [AudioTrack initWithDictionary:item];
    if (newTrack) {
        NSMutableArray* tempArr = [NSMutableArray arrayWithObject:newTrack];
        [self addTracks:tempArr];
    }

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) addAllItems:(CDVInvokedUrlCommand *) command {
    NSMutableArray* items = [command.arguments objectAtIndex:0];
    NSLog(@"RmxAudioPlayer.execute=addAllItems, %@", items);

    [self insertOrReplaceTracks:items replace:NO startPosition:-1];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) removeItems:(CDVInvokedUrlCommand *) command {
    NSMutableArray* items = [command.arguments objectAtIndex:0];
    NSLog(@"RmxAudioPlayer.execute=removeItems, %@", items);

    int removed = 0;
    if (items != nil || items.count > 0) {
        for (NSDictionary *item in items) {
            NSString* trackIndex = [item objectForKey:@"trackIndex"];
            NSString* trackId = [item objectForKey:@"trackId"];

            if ([self removeItemWithValues:trackIndex trackId:trackId]) {
                removed++;
            }
        }
    }

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsInt:removed];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) removeItem:(CDVInvokedUrlCommand *) command {
    NSString* trackIndex = [command.arguments objectAtIndex:0];
    NSString* trackId = [command.arguments objectAtIndex:1];

    NSLog(@"RmxAudioPlayer.execute=removeItem, %@, %@", trackId, trackIndex);

    BOOL success = [self removeItemWithValues:trackIndex trackId:trackId];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsBool:success];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) clearAllItems:(CDVInvokedUrlCommand*) command {
    NSLog(@"RmxAudioPlayer.execute=clearAllItems");
    [self removeAllTracks:NO];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) play:(CDVInvokedUrlCommand *) command {
    NSLog(@"RmxAudioPlayer.execute=play");
    [self playCommand:NO];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) playTrackByIndex:(CDVInvokedUrlCommand *) command {
    NSNumber* argVal = [command argumentAtIndex:0 withDefault:[NSNumber numberWithInt:0]];

    NSLog(@"RmxAudioPlayer.execute=playTrackByIndex, %@", argVal);
    int index = argVal.intValue;

    if (index < 0 || index >= [self avQueuePlayer].itemsForPlayer.count) {
        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsString:@"Provided index is out of bounds"];
        [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
    } else {
        [self avQueuePlayer].currentIndex = argVal.intValue;
        [self playCommand:NO];

        NSNumber* argVal1 = [command argumentAtIndex:1 withDefault:[NSNumber numberWithFloat:0.0]];
        float positionTime = argVal1.floatValue;
        [self seekTo:positionTime isCommand:NO];

        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
        [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
    }
}


- (void) playTrackById:(CDVInvokedUrlCommand *) command {
    NSString* trackId = [command.arguments objectAtIndex:0];
    NSLog(@"RmxAudioPlayer.execute=playTrackById, %@", trackId);

    NSDictionary* result = [self findTrackById:trackId];
    NSInteger idx = [(NSNumber*)result[@"index"] integerValue];
    // AudioTrack* track = result[@"track"];

    if ([self avQueuePlayer].itemsForPlayer.count > 0) {
        if (idx >= 0) {
            [self avQueuePlayer].currentIndex = idx;
            [self playCommand:NO];

            NSNumber* argVal = [command argumentAtIndex:1 withDefault:[NSNumber numberWithFloat:0.0]];
            float positionTime = argVal.floatValue;
            [self seekTo:positionTime isCommand:NO];

            CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsNSUInteger:idx];
            [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
        } else {
            CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsString:@"Track ID not found"];
            [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
        }
    } else {
        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsString:@"The playlist is empty!"];
        [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
    }
}


- (void) pause:(CDVInvokedUrlCommand *) command {
    NSLog(@"RmxAudioPlayer.execute=pause");
    _isWaitingToStartPlayback = NO;
    [self pauseCommand:NO];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) skipForward:(CDVInvokedUrlCommand *) command {
    NSLog(@"RmxAudioPlayer.execute=skipForward");
    [self playNext:NO];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) skipBack:(CDVInvokedUrlCommand *) command {
    NSLog(@"RmxAudioPlayer.execute=skipBack");
    [self playPrevious:NO];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) seekTo:(CDVInvokedUrlCommand *) command {
    NSNumber* argVal = [command argumentAtIndex:0 withDefault:[NSNumber numberWithFloat:0.0]];
    NSLog(@"RmxAudioPlayer.execute=seekTo, %@", argVal);

    float positionTime = argVal.floatValue;
    [self seekTo:positionTime isCommand:YES];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) seekToQueuePosition:(CDVInvokedUrlCommand *) command {
    NSNumber* argVal = [command argumentAtIndex:0 withDefault:[NSNumber numberWithFloat:0.0]];
    NSLog(@"RmxAudioPlayer.execute=seekToQueuePosition, %@", argVal);

    float positionTime = argVal.floatValue;

    [[self avQueuePlayer] seekToTimeInQueue:CMTimeMakeWithSeconds(positionTime, NSEC_PER_SEC) completionHandler:^(BOOL complete) {
        // I guess we could check if the seek actually succeeded.
        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
        [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
    }];
}


- (void) setPlaybackRate:(CDVInvokedUrlCommand *) command {
    NSNumber* argVal = [command argumentAtIndex:0 withDefault:[NSNumber numberWithFloat:1.0]];
    NSLog(@"RmxAudioPlayer.execute=setPlaybackRate, %@", argVal);

    self.rate = argVal.floatValue;

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) setPlaybackVolume:(CDVInvokedUrlCommand *) command {
    NSNumber* argVal = [command argumentAtIndex:0 withDefault:[NSNumber numberWithFloat:self.volume]];
    NSLog(@"RmxAudioPlayer.execute=setPlaybackVolume, %@", argVal);

    self.volume = argVal.floatValue;

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) setLoopAll:(CDVInvokedUrlCommand *) command {
    id loop2 = [command argumentAtIndex:0];
    if (([loop2 isKindOfClass:[NSString class]] && [loop2 isEqualToString:@"true"]) || [loop2 boolValue]) {
        self.loop = YES;
    } else {
        self.loop = NO;
    }
    NSLog(@"RmxAudioPlayer.execute=setLoopAll, %@", loop2);

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) getPlaybackRate:(CDVInvokedUrlCommand *) command {
    NSLog(@"RmxAudioPlayer.execute=getPlaybackRate, %f", self.rate);
    float rate = self.rate;

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDouble:rate];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) getPlaybackVolume:(CDVInvokedUrlCommand *) command {
    NSLog(@"RmxAudioPlayer.execute=getPlaybackVolume, %f", self.volume);
    float volume = self.volume;

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDouble:volume];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) getPlaybackPosition:(CDVInvokedUrlCommand *) command {
    float currentPosition = [self getTrackCurrentTime:nil];
    NSLog(@"RmxAudioPlayer.execute=getPlaybackPosition, %f", currentPosition);

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDouble:currentPosition];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) getCurrentBuffer:(CDVInvokedUrlCommand *) command {
    NSDictionary* trackStatus = [self getPlayerStatusItem:nil];
    NSLog(@"RmxAudioPlayer.execute=getCurrentBuffer, %@", trackStatus);

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDictionary:trackStatus];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) getQueuePosition:(CDVInvokedUrlCommand *) command {
    float position = self.queuePosition;
    NSLog(@"RmxAudioPlayer.execute=getQueuePosition, %f", position);

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDouble:position];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


- (void) release:(CDVInvokedUrlCommand*)command {
    NSLog(@"RmxAudioPlayer.execute=release");
    _isWaitingToStartPlayback = NO;
    [self releaseResources];

    CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    [self.commandDelegate sendPluginResult:result callbackId:command.callbackId];
}


/* ****** */
/* Utilities for the above functions */

- (void) insertOrReplaceTracks:(NSArray*)items replace:(BOOL)replace startPosition:(float)startPosition {
    if (items == nil || items.count == 0) {
        return;
    }

    NSMutableArray* newList = [NSMutableArray arrayWithCapacity:items.count];
    for (NSDictionary *item in items) {
        AudioTrack* track = [AudioTrack initWithDictionary:item];
        if (track) {
            [newList addObject:track];
        }
    }

    if (replace) {
        [self setTracks:newList startPosition:startPosition];
    } else {
        [self addTracks:newList];
    }
}

- (BOOL) removeItemWithValues:(NSString*)trackIndex trackId:(NSString*)trackId {
    if ((id)trackIndex != [NSNull null]
        && [trackIndex integerValue] > 0
        && [trackIndex integerValue] < [self avQueuePlayer].itemsForPlayer.count
        ) {
        AudioTrack* item = [self avQueuePlayer].itemsForPlayer[[trackIndex integerValue]];
        [self removeTrackObservers:item];
        [[self avQueuePlayer] removeItem:item];
        return YES;
    } else if ((id)trackId != [NSNull null] && ![trackId isEqualToString:@""]) {
        NSDictionary* result = [self findTrackById:trackId];
        NSInteger idx = [(NSNumber*)result[@"index"] integerValue];
        AudioTrack* track = result[@"track"];

        if (idx >= 0) {
            // AudioTrack* item = [self avQueuePlayer].itemsForPlayer[idx];
            [self removeTrackObservers:track];
            [[self avQueuePlayer] removeItem:track];
            return YES;
        } else {
            return NO;
        }
    } else {
        return NO;
    }
}


#pragma mark - player actions

/**
 *
 * Player actions.
 *
 * These are the public API for the player and wrap most of the complexity of the queue.
 *
 *
 *
 *
 *
 *
 *
 */

- (void) playCommand:(BOOL)isCommand
{
    _wasPlayingInterrupted = NO;
    [self initializeMPCommandCenter];
    // [[self avQueuePlayer] play];

    if (_resetStreamOnPause) {
        AudioTrack* currentTrack = (AudioTrack*)[self avQueuePlayer].currentItem;
        if (currentTrack != nil && currentTrack.isStream) {
            [[self avQueuePlayer] seekToTime:kCMTimePositiveInfinity toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];
            [currentTrack seekToTime:kCMTimePositiveInfinity toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero completionHandler:nil];
        }
    }

    [self avQueuePlayer].rate = self.rate;
    [self avQueuePlayer].volume = self.volume;

    if (isCommand) {
        NSString * action = @"music-controls-play";
        NSLog(@"%@", action);
    }
}

- (void) pauseCommand:(BOOL)isCommand
{
    _wasPlayingInterrupted = NO;
    [self initializeMPCommandCenter];
    [[self avQueuePlayer] pause];

    // When the track is a stream, we do not want it to hold the buffer at the current location;
    // it does in fact continue buffering afterwards but the buffer on iOS is rather small, so you'll end up
    // reaching a point where you jump forward in time however long you were paused.
    // The correct behavior for streams is to pick up at the current LIVE point in the stream, which we accomplish
    // by seeking to the "end" of the stream.
    if (_resetStreamOnPause) {
        AudioTrack* currentTrack = (AudioTrack*)[self avQueuePlayer].currentItem;
        if (currentTrack != nil && currentTrack.isStream) {
            [[self avQueuePlayer] seekToTime:kCMTimePositiveInfinity toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];
            [currentTrack seekToTime:kCMTimePositiveInfinity toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero completionHandler:nil];
        }
    }

    if (isCommand) {
        NSString * action = @"music-controls-pause";
        NSLog(@"%@", action);
    }
}

- (void) playPrevious:(BOOL)isCommand
{
    _wasPlayingInterrupted = NO;
    [self initializeMPCommandCenter];

    [[self avQueuePlayer] playPreviousItem];

    if (isCommand) {
        NSString * action = @"music-controls-previous";
        NSLog(@"%@", action);

        AudioTrack* playerItem = (AudioTrack*)[self avQueuePlayer].currentItem;
        NSDictionary* param = @{
                                @"currentIndex": @([self avQueuePlayer].currentIndex),
                                @"currentItem": [playerItem toDict]
                                };
        [self onStatus:RMX_STATUS_SKIP_BACK trackId:playerItem.trackId param:param];
    }
}

- (void) playNext:(BOOL)isCommand
{
    _wasPlayingInterrupted = NO;
    [self initializeMPCommandCenter];

    [[self avQueuePlayer] advanceToNextItem];

    if (isCommand) {
        NSString * action = @"music-controls-next";
        NSLog(@"%@", action);

        AudioTrack* playerItem = (AudioTrack *)[self avQueuePlayer].currentItem;
        NSDictionary* param = @{
                                @"currentIndex": @([self avQueuePlayer].currentIndex),
                                @"currentItem": [playerItem toDict]
                                };
        [self onStatus:RMX_STATUS_SKIP_FORWARD trackId:playerItem.trackId param:param];
    }
}

- (void) seekTo:(float)positionTime isCommand:(BOOL)isCommand
{
    //Handle seeking with the progress slider on lockscreen or control center
    _wasPlayingInterrupted = NO;
    [self initializeMPCommandCenter];

    CMTime seekToTime = CMTimeMakeWithSeconds(positionTime, 1000);
    [[self avQueuePlayer] seekToTime:seekToTime toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];

    NSString * action = @"music-controls-seek-to";
    NSLog(@"%@ %.3f", action, positionTime);

    if (isCommand) {
        AudioTrack* playerItem = (AudioTrack *)[self avQueuePlayer].currentItem;
        [self onStatus:RMXSTATUS_SEEK trackId:playerItem.trackId param:@{@"position": @(positionTime)}];
    }
}

- (float) rate
{
    return _rate;
}

- (void) setRate:(float)rate
{
    _rate = rate;
    [self avQueuePlayer].rate = rate;
}

- (float) volume
{
    return _volume;
}

- (void) setVolume:(float)volume
{
    _volume = volume;
    [self avQueuePlayer].volume = volume;
}

- (void) addTracks:(NSMutableArray<AudioTrack*>*)tracks
{
    for (AudioTrack* playerItem in tracks) {
        [self addTrackObservers:playerItem];
    }

    [[self avQueuePlayer] insertAllItems:tracks];
}

- (void) setTracks:(NSMutableArray<AudioTrack*>*)tracks startPosition:(float)startPosition
{
    for (AudioTrack* item in [self avQueuePlayer].itemsForPlayer) {
        [self removeTrackObservers:item];
    }

    for (AudioTrack* playerItem in tracks) {
        [self addTrackObservers:playerItem];
    }

    _isReplacingItems = YES;
    [[self avQueuePlayer] setItemsForPlayer:tracks];

    if (startPosition > 0) {
        [self seekTo:startPosition isCommand:NO];
    }
}

- (void) removeAllTracks:(BOOL)isCommand
{
    for (AudioTrack* item in [self avQueuePlayer].itemsForPlayer) {
        [self removeTrackObservers:item];
    }

    [[self avQueuePlayer] removeAllItems];
    _wasPlayingInterrupted = NO;

    NSLog(@"RmxAudioPlayer, removeAllTracks, ==> RMXSTATUS_PLAYLIST_CLEARED");
    [self onStatus:RMXSTATUS_PLAYLIST_CLEARED trackId:@"INVALID" param:nil];

    // a.t.m there's no way for this to be triggered from within the plugin,
    // but it might get added at some point.
    if (isCommand) {
        NSString * action = @"music-controls-clear";
        NSLog(@"%@", action);
    }
}


#pragma mark - remote control events

/**
 *
 * Events - receive events from the iOS remote controls and command center.
 *
 *
 *
 *
 *
 *
 *
 *
 */

- (MPRemoteCommandHandlerStatus) playEvent:(MPRemoteCommandEvent *)event {
    [self playCommand:YES];
    return MPRemoteCommandHandlerStatusSuccess;
}

- (MPRemoteCommandHandlerStatus) pauseEvent:(MPRemoteCommandEvent *)event {
    [self pauseCommand:YES];
    return MPRemoteCommandHandlerStatusSuccess;
}

- (MPRemoteCommandHandlerStatus) togglePlayPauseTrackEvent:(MPRemoteCommandEvent *)event {
    if ([self avQueuePlayer].isPlaying) {
        [self pauseCommand:YES];
    } else {
        [self playCommand:YES];
    }
    return MPRemoteCommandHandlerStatusSuccess;
}

- (MPRemoteCommandHandlerStatus) prevTrackEvent:(MPRemoteCommandEvent *)event {
    [self playPrevious:YES];
    return MPRemoteCommandHandlerStatusSuccess;
}

- (MPRemoteCommandHandlerStatus) nextTrackEvent:(MPRemoteCommandEvent *)event {
    [self playNext:YES];
    return MPRemoteCommandHandlerStatusSuccess;
}

- (MPRemoteCommandHandlerStatus) changedThumbSliderOnLockScreen:(MPChangePlaybackPositionCommandEvent *)event {
    [self seekTo:event.positionTime isCommand:YES];
    return MPRemoteCommandHandlerStatusSuccess;
}


#pragma mark - notifications

/**
 *
 * Notifications
 *
 * These handle the events raised by the queue and the player items.
 *
 *
 *
 *
 *
 *
 *
 */

- (void) itemStalledPlaying:(NSNotification *) notification {
    // This happens when the network is insufficient to continue playback.
    AudioTrack* playerItem = (AudioTrack*)[self avQueuePlayer].currentItem;
    NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];
    [self onStatus:RMXSTATUS_STALLED trackId:playerItem.trackId param:trackStatus];
    [self onStatus:RMXSTATUS_PAUSE trackId:playerItem.trackId param:trackStatus];
}

- (void) playerItemDidReachEnd:(NSNotification *) notification {
    NSLog(@"Player item reached end: %@", notification.object);
    AudioTrack* playerItem = (AudioTrack*)notification.object;
    // When an item finishes, immediately scrub it back to the beginning
    // so that the visual indicators show you can "play again" or whatever.
    // Might make sense to have a flag for this behavior.
    [playerItem seekToTime:kCMTimeZero toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero completionHandler:nil];

    NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];
    [self onStatus:RMXSTATUS_COMPLETED trackId:playerItem.trackId param:trackStatus];
}

- (void) handleAudioSessionInterruption:(NSNotification*)interruptionNotification
{
    NSLog(@"Audio session interruption received: %@", interruptionNotification);

    NSDictionary* userInfo = interruptionNotification.userInfo;
    AVAudioSessionInterruptionType interruptionType = [userInfo[AVAudioSessionInterruptionTypeKey] unsignedIntegerValue];

    switch (interruptionType) {
        case AVAudioSessionInterruptionTypeBegan: {
            BOOL suspended = [userInfo[AVAudioSessionInterruptionWasSuspendedKey] boolValue];
            NSLog(@"AVAudioSessionInterruptionTypeBegan. Was suspended: %d", suspended);
            if ([[self avQueuePlayer] isPlaying]) {
                _wasPlayingInterrupted = YES;
            }

            // [[self avQueuePlayer] pause];
            [self pauseCommand:NO];
            break;
        }
        case AVAudioSessionInterruptionTypeEnded: {
            NSLog(@"AVAudioSessionInterruptionTypeEnded");
            AVAudioSessionInterruptionOptions interruptionOption = [userInfo[AVAudioSessionInterruptionOptionKey] unsignedIntegerValue];
            if (interruptionOption == AVAudioSessionInterruptionOptionShouldResume) {
                if (_wasPlayingInterrupted) {
                    [[self avQueuePlayer] play];
                }
            }
            _wasPlayingInterrupted = NO;
            break;
        }
        default:
            break;
    }
}

/*
 * This method only executes while the queue is playing, so we can use the playback position event.
 */
- (void) executePeriodicUpdate:(CMTime)time {
    AudioTrack *playerItem = (AudioTrack *)[self avQueuePlayer].currentItem;

    if (!CMTIME_IS_INDEFINITE(playerItem.currentTime)) {
        [self updateNowPlayingTrackInfo:playerItem updateTrackData:NO];

        if([[self avQueuePlayer] isPlaying]) {
            NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];
            [self onStatus:RMXSTATUS_PLAYBACK_POSITION trackId:playerItem.trackId param:trackStatus];
            // NSLog(@" . %.5f / %.5f sec (%.1f %%) [%@]", currentTime, duration, (currentTime / duration)*100.0, name);
        }
    }

    return;
}


- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"currentItem"] && context == &kAvQueuePlayerContext)
    {
        AVBidirectionalQueuePlayer *player = (AVBidirectionalQueuePlayer *)object;
        AudioTrack *playerItem = (AudioTrack *)player.currentItem;
        [self handlePlayerCurrentItemChanged:playerItem];
        return;
    }

    if ([keyPath isEqualToString:@"rate"] && context == &kAvQueuePlayerRateContext)
    {
        AVBidirectionalQueuePlayer *player = (AVBidirectionalQueuePlayer *)object;
        AudioTrack *playerItem = (AudioTrack *)player.currentItem;

        if (playerItem == nil) {
            return;
        }

        NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];
        NSLog(@"Playback rate changed: %f, is playing: %d", player.rate, player.isPlaying);

        if (player.isPlaying) {
            [self onStatus:RMXSTATUS_PLAYING trackId:playerItem.trackId param:trackStatus];
        } else {
            [self onStatus:RMXSTATUS_PAUSE trackId:playerItem.trackId param:trackStatus];
        }
        return;
    }

    if ([keyPath isEqualToString:@"status"] && context == &kPlayerItemStatusContext)
    {
        AudioTrack *playerItem = (AudioTrack *)object;
        [self handleTrackStatusEvent:playerItem];
        return;
    }

    if ([keyPath isEqualToString:@"duration"] && context == &kPlayerItemDurationContext)
    {
        AudioTrack *playerItem = (AudioTrack *)object;
        [self handleTrackDuration:playerItem];
        return;
    }

    if ([keyPath isEqualToString:@"loadedTimeRanges"] && context == &kPlayerItemTimeRangesContext)
    {
        AudioTrack *playerItem = (AudioTrack *)object;
        [self handleTrackBuffering:playerItem];
        return;
    }

    [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    return;
}


- (void) updateNowPlayingTrackInfo:(AudioTrack*)playerItem updateTrackData:(BOOL)updateTrackData
{
    AudioTrack* currentItem = playerItem;
    if (currentItem == nil) {
        currentItem = (AudioTrack*)[self avQueuePlayer].currentItem;
    }

    MPNowPlayingInfoCenter* nowPlayingInfoCenter =  [MPNowPlayingInfoCenter defaultCenter];
    if (_updatedNowPlayingInfo == nil) {
        NSDictionary* nowPlayingInfo = nowPlayingInfoCenter.nowPlayingInfo;
        _updatedNowPlayingInfo = [NSMutableDictionary dictionaryWithDictionary:nowPlayingInfo];
    }

    // for (NSString* val in _updatedNowPlayingInfo.allKeys) {
    //     NSLog(@"%@ ==> %@", val, _updatedNowPlayingInfo[val]);
    // }

    float currentTime = CMTimeGetSeconds(currentItem.currentTime);
    float duration = CMTimeGetSeconds(currentItem.duration);
    if (CMTIME_IS_INDEFINITE(currentItem.duration)) {
        duration = 0;
    }

    if (updateTrackData) {
        _updatedNowPlayingInfo[MPMediaItemPropertyArtist] = currentItem.artist;
        _updatedNowPlayingInfo[MPMediaItemPropertyTitle] = currentItem.title;
        _updatedNowPlayingInfo[MPMediaItemPropertyAlbumTitle] = currentItem.album;
        MPMediaItemArtwork* mediaItemArtwork = [self createCoverArtwork:[currentItem.albumArt absoluteString]];

        if (mediaItemArtwork != nil) {
            [_updatedNowPlayingInfo setObject:mediaItemArtwork forKey:MPMediaItemPropertyArtwork];
        }
    }

    _updatedNowPlayingInfo[MPMediaItemPropertyPlaybackDuration] = [NSNumber numberWithFloat:duration];
    _updatedNowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = [NSNumber numberWithFloat:currentTime];
    _updatedNowPlayingInfo[MPNowPlayingInfoPropertyPlaybackRate] = [NSNumber numberWithFloat:1.0];

    nowPlayingInfoCenter.nowPlayingInfo = _updatedNowPlayingInfo;

    MPRemoteCommandCenter *commandCenter = [MPRemoteCommandCenter sharedCommandCenter];
    [commandCenter.nextTrackCommand setEnabled:!self.isAtEnd];
    [commandCenter.previousTrackCommand setEnabled:!self.isAtBeginning];
}

- (MPMediaItemArtwork *) createCoverArtwork: (NSString *) coverUri {
    UIImage * coverImage = nil;
    if (coverUri == nil) {
        return nil;
    }

    if ([coverUri.lowercaseString hasPrefix:@"file://"]) {
        NSString * fullCoverImagePath = [coverUri stringByReplacingOccurrencesOfString:@"file://" withString:@""];

        if ([[NSFileManager defaultManager] fileExistsAtPath: fullCoverImagePath]) {
            coverImage = [[UIImage alloc] initWithContentsOfFile: fullCoverImagePath];
        }
    }
    else if ([coverUri hasPrefix:@"http://"] || [coverUri hasPrefix:@"https://"]) {
        NSURL * coverImageUrl = [NSURL URLWithString:coverUri];
        NSData * coverImageData = [NSData dataWithContentsOfURL: coverImageUrl];

        coverImage = [UIImage imageWithData: coverImageData];
    }
    else if (![coverUri isEqual:@""]) {
        NSString * baseCoverImagePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
        NSString * fullCoverImagePath = [NSString stringWithFormat:@"%@%@", baseCoverImagePath, coverUri];

        if ([[NSFileManager defaultManager] fileExistsAtPath:fullCoverImagePath]) {
            coverImage = [UIImage imageNamed:fullCoverImagePath];
        }
    }
    else {
        coverImage = [UIImage imageNamed:@"none"];
    }

    return [self isCoverImageValid:coverImage] ? [[MPMediaItemArtwork alloc] initWithImage:coverImage] : nil;
}

- (bool) isCoverImageValid: (UIImage *) coverImage {
    return coverImage != nil && ([coverImage CIImage] != nil || [coverImage CGImage] != nil);
}

- (void) handlePlayerCurrentItemChanged:(AudioTrack*)playerItem
{
    NSLog(@"Queue changed current item to: %@", [playerItem toDict]);
    // NSLog(@"New music name: %@", ((AVURLAsset*)playerItem.asset).URL.pathComponents.lastObject);
    NSLog(@"New item ID: %@", playerItem.trackId);
    NSLog(@"Queue is at end: %@", self.isAtEnd ? @"YES" : @"NO");
    NSLog(@"Queue changed current item to: %@", playerItem != nil ? @"NOTNIL" : @"NIL");

    if (playerItem != nil) {
        // When an item starts, immediately scrub it back to the beginning
        [playerItem seekToTime:kCMTimeZero toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero completionHandler:nil];
        // Update the command center
        [self updateNowPlayingTrackInfo:playerItem updateTrackData:YES];
    }
    else if (self.loop){
        return;
    }

    NSDictionary* info = @{
                           @"currentItem": playerItem != nil ? [playerItem toDict] : @{},
                           @"currentIndex": @([self avQueuePlayer].currentIndex),
                           @"isAtEnd": @(self.isAtEnd),
                           @"isAtBeginning": @(self.isAtBeginning),
                           @"hasNext": @(!self.isAtEnd),
                           @"hasPrevious": @(!self.isAtBeginning)
                           };
    NSString* trackId = playerItem != nil ? playerItem.trackId : @"NONE";
    [self onStatus:RMXSTATUS_TRACK_CHANGED trackId:trackId param:info];

    if ([[self avQueuePlayer] isAtEnd] && [self avQueuePlayer].currentItem == nil) {
        [[self avQueuePlayer] seekToTime:kCMTimeZero toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];

        if ([self avQueuePlayer].itemsForPlayer.count > 0 && !_isReplacingItems) {
            [self onStatus:RMXSTATUS_PLAYLIST_COMPLETED trackId:@"INVALID" param:nil];
        }

        if (self.loop && [self avQueuePlayer].itemsForPlayer.count > 0) {
            [[self avQueuePlayer] play];
        } else {
            [self onStatus:RMXSTATUS_STOPPED trackId:@"INVALID" param:nil];
        }
    }
}


- (void) handleTrackStatusEvent:(AudioTrack*)playerItem
{
    // NSString* name = ((AVURLAsset*)playerItem.asset).URL.pathComponents.lastObject;
    NSString* name = playerItem.trackId;
    AVPlayerItemStatus status = playerItem.status;

    // Switch over the status
    switch (status) {
        case AVPlayerItemStatusReadyToPlay: {
            NSLog(@"PlayerItem status changed to AVPlayerItemStatusReadyToPlay [%@]", name);
            NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];
            [self onStatus:RMXSTATUS_CANPLAY trackId:playerItem.trackId param:trackStatus];

            if (_isWaitingToStartPlayback) {
                _isWaitingToStartPlayback = NO;
                NSLog(@"RmxAudioPlayer[setPlaylistItems] is beginning playback after waiting for ReadyToPlay event");
                [self playCommand:NO];
            }
            break;
        }
        case AVPlayerItemStatusFailed: {
            // Failed. Examine AVPlayerItem.error
            _isWaitingToStartPlayback = NO;
            NSString* errorMsg = @"";
            if (playerItem.error) {
                errorMsg = [NSString stringWithFormat:@"Error playing audio track: %@", [playerItem.error localizedFailureReason]];
            }
            NSLog(@"AVPlayerItemStatusFailed: Error playing audio track: %@", errorMsg);
            NSDictionary* errorParam = [self createErrorWithCode:RMXERR_DECODE message:errorMsg];
            [self onStatus:RMXSTATUS_ERROR trackId:playerItem.trackId param:errorParam];
            break;
        }
        case AVPlayerItemStatusUnknown:
            _isWaitingToStartPlayback = NO;
            NSLog(@"PlayerItem status changed to AVPlayerItemStatusUnknown [%@]", name);
            // Not ready
            break;
        default:
            break;
    }
}

- (void) handleTrackDuration:(AudioTrack*)playerItem
{
    // This function isn't all that useful really in terms of state management.
    // It doesn't always fire, and it is not needed because the queue's periodic update can also
    // deliver this info.
    //NSString* name = ((AVURLAsset*)playerItem.asset).URL.pathComponents.lastObject;
    NSString* name = playerItem.trackId;
    if (!CMTIME_IS_INDEFINITE(playerItem.duration)) {
        float duration = CMTimeGetSeconds(playerItem.duration);
        NSLog(@"The track duration was changed [%@]: %f", name, duration);

        // We will still report the duration though.
        NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];
        [self onStatus:RMXSTATUS_DURATION trackId:playerItem.trackId param:trackStatus];
    } else {
        NSLog(@"Item duration is indefinite (unknown): %@", ((AVURLAsset*)playerItem.asset).URL);
    }
}

- (void) handleTrackBuffering:(AudioTrack*)playerItem
{
    //NSString* name = ((AVURLAsset*)playerItem.asset).URL.pathComponents.lastObject;
    NSString* name = playerItem.trackId;
    NSDictionary* trackStatus = [self getPlayerStatusItem:playerItem];

    NSLog(@" . . . %.5f -> %.5f (%.1f %%) [%@]",
          [trackStatus[@"bufferStart"] floatValue],
          [trackStatus[@"bufferStart"] floatValue] + [trackStatus[@"bufferEnd"] floatValue],
          [trackStatus[@"bufferPercent"] floatValue], name);

    [self onStatus:RMXSTATUS_BUFFERING trackId:playerItem.trackId param:trackStatus];

    if ([trackStatus[@"bufferPercent"] floatValue] >= 100.0) {
        [self onStatus:RMXSTATUS_LOADED trackId:playerItem.trackId param:trackStatus];
    }
}


/**
 *
 * Status utilities
 *
 * These provide the statis objects and data for the player items when they update.
 *
 * It is largely this data that is actually reported to the consumers.
 *
 *
 *
 *
 *
 */

// Not really needed, the dicts do this themselves but, blah.
- (NSNumber*) getNumberForString:(NSString*)str {
    NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
    f.numberStyle = NSNumberFormatterDecimalStyle;
    [f setLocale:[NSLocale currentLocale]];
    return [f numberFromString:str];
}

- (NSDictionary*) getPlayerStatusItem:(AudioTrack*)playerItem
{
    AudioTrack* currentItem = playerItem;
    if (currentItem == nil) {
        currentItem = (AudioTrack*)[self avQueuePlayer].currentItem;
    }

    if (currentItem == nil) {
        return nil;
    }

    NSDictionary* bufferInfo = [self getTrackBufferInfo:currentItem];
    float position = [self getTrackCurrentTime:currentItem];
    float duration = [bufferInfo[@"duration"] floatValue];

    // Correct this value here, so that playbackPercent is not set to INFINITY
    if (isnan(position) || isinf(position)) {
        position = 0.0f;
    }

    float playbackPercent = duration > 0 ? (position / duration) * 100.0 : 0.0f;

    NSString* status = @"";
    if (currentItem.status == AVPlayerItemStatusReadyToPlay) {
        status = @"ready";
    } else if (currentItem.status == AVPlayerItemStatusFailed) {
        status = @"error";
    } else {
        status = @"unknown";
    }

    if ([self avQueuePlayer].currentItem == currentItem) {
        if ([self avQueuePlayer].rate != 0.0f) {
            status = @"playing";

            if (position <= 0 && [bufferInfo[@"bufferPercent"] floatValue] == 0) {
                status = @"loading";
            }
        } else {
            status = @"paused";
        }
    }

    NSDictionary *info = @{
                           @"trackId": currentItem.trackId,
                           @"isStream": currentItem.isStream ? @(1) : @(0),
                           @"currentIndex": @([self avQueuePlayer].currentIndex),
                           @"status": status,
                           @"currentPosition": @(position),
                           @"duration": @(duration),
                           @"playbackPercent": @(playbackPercent),
                           @"bufferPercent": @([bufferInfo[@"bufferPercent"] floatValue]),
                           @"bufferStart": @([bufferInfo[@"start"] floatValue]),
                           @"bufferEnd": @([bufferInfo[@"end"] floatValue])
                           };
    return info;
}

- (float) getTrackCurrentTime:(AudioTrack*)playerItem
{
    AudioTrack* currentItem = playerItem;
    if (currentItem == nil) {
        currentItem = (AudioTrack*)[self avQueuePlayer].currentItem;
    }

    if (currentItem == nil) {
        return 0.0f;
    }

    if (!CMTIME_IS_INDEFINITE(currentItem.currentTime) && CMTIME_IS_VALID(currentItem.currentTime)) {
        return CMTimeGetSeconds(currentItem.currentTime);
    } else {
        return 0.0f;
    }
}

- (NSDictionary*) getTrackBufferInfo:(AudioTrack*)playerItem
{
    if (!CMTIME_IS_INDEFINITE(playerItem.duration)) {
        float duration = CMTimeGetSeconds(playerItem.duration);
        NSArray *timeRanges = [playerItem loadedTimeRanges];
        if (timeRanges && [timeRanges count]) {
            CMTimeRange timerange = [[timeRanges objectAtIndex:0] CMTimeRangeValue];
            float start = CMTimeGetSeconds(timerange.start);
            float rangeEnd = CMTimeGetSeconds(timerange.duration);
            float bufferPercent = (rangeEnd / duration) * 100.0;

            NSDictionary* bufferInfo = @{
                                         @"start": @(start),
                                         @"end": @(rangeEnd),
                                         @"bufferPercent": @(bufferPercent),
                                         @"duration": @(duration)
                                         };
            return bufferInfo;
        } else {
            NSDictionary* bufferInfo = @{@"start": @0.0, @"end": @0.0, @"bufferPercent": @0.0, @"duration": @(duration)};
            return bufferInfo;
        }
    }

    NSDictionary* bufferInfo = @{@"start": @0.0, @"end": @0.0, @"bufferPercent": @0.0, @"duration": @0.0};
    return bufferInfo;
}


#pragma mark - plugin initialization

/**
 *
 * Object initialization. Mostly boring plumbing to initialize the objects and wire everything up.
 *
 *
 *
 *
 *
 *
 *
 *
 */

- (void) initializeMPCommandCenter
{
    if (!_commandCenterRegistered) {
        MPRemoteCommandCenter *commandCenter = [MPRemoteCommandCenter sharedCommandCenter];
        [commandCenter.playCommand setEnabled:true];
        [commandCenter.playCommand addTarget:self action:@selector(playEvent:)];
        [commandCenter.pauseCommand setEnabled:true];
        [commandCenter.pauseCommand addTarget:self action:@selector(pauseEvent:)];
        [commandCenter.nextTrackCommand setEnabled:true];
        [commandCenter.nextTrackCommand addTarget:self action:@selector(nextTrackEvent:)];
        [commandCenter.previousTrackCommand setEnabled:true];
        [commandCenter.previousTrackCommand addTarget:self action:@selector(prevTrackEvent:)];
        [commandCenter.togglePlayPauseCommand setEnabled:true];
        [commandCenter.togglePlayPauseCommand addTarget:self action:@selector(togglePlayPauseTrackEvent:)];

        if (@available(iOS 9.0, *)) {
            [commandCenter.changePlaybackPositionCommand setEnabled:true];
            [commandCenter.changePlaybackPositionCommand addTarget:self action:@selector(changedThumbSliderOnLockScreen:)];
        }

        _commandCenterRegistered = YES;
    }
}

- (NSMutableArray*) currentItems
{
    return [self avQueuePlayer].itemsForPlayer;
}

//- (NSUInteger) currentIndex {
//  return [self avQueuePlayer].currentIndex;
//}

- (BOOL) isAtEnd {
    return [self avQueuePlayer].isAtEnd;
}

- (BOOL) isAtBeginning {
    return [self avQueuePlayer].isAtBeginning;
}

- (BOOL) isPlaying {
    return [self avQueuePlayer].isPlaying;
}

- (float) queuePosition {
    return CMTimeGetSeconds([self avQueuePlayer].currentTimeOffsetInQueue);
}

- (AVBidirectionalQueuePlayer *) avQueuePlayer
{
    if (!_avQueuePlayer) {
        NSArray* queue = @[];

        _avQueuePlayer = [[AVBidirectionalQueuePlayer alloc] initWithItems:queue];
        _avQueuePlayer.actionAtItemEnd = AVPlayerActionAtItemEndAdvance;
        [_avQueuePlayer addObserver:self forKeyPath:@"currentItem" options:NSKeyValueObservingOptionNew context:&kAvQueuePlayerContext];
        [_avQueuePlayer addObserver:self forKeyPath:@"rate" options:NSKeyValueObservingOptionNew context:&kAvQueuePlayerRateContext];

        CMTime interval = CMTimeMakeWithSeconds(1.0, NSEC_PER_SEC);
        __typeof(self) __weak weakSelf = self;
        dispatch_queue_t mainQueue = dispatch_get_main_queue();
        _playbackTimeObserver = [_avQueuePlayer addPeriodicTimeObserverForInterval:interval queue:mainQueue usingBlock:^(CMTime time) {
            __typeof(weakSelf) __strong strongSelf = weakSelf;
            if (strongSelf) {
                [strongSelf executePeriodicUpdate:time];
            }
        }];

        // Put this behind a flag.
        _avQueuePlayer.automaticallyWaitsToMinimizeStalling = NO;
    }

    return _avQueuePlayer;
}

- (NSDictionary*) findTrackById:(NSString*)trackId {
    NSInteger idx = -1;
    AudioTrack* track = nil;

    if ([self avQueuePlayer].itemsForPlayer.count > 0) {
        NSMutableArray* arr = [self avQueuePlayer].itemsForPlayer;
        NSIndexSet *indexes = [arr indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
            return [((AudioTrack *)obj).trackId isEqualToString:trackId];
        }];

        if (indexes.count > 0) {
            idx = indexes.firstIndex;
            track = (AudioTrack*)arr[idx];
        }
    }

    // nil values are not permitted in NSDictionary; use NSNull instead
    return @{
             @"track": track ? track : [NSNull null],
             @"index": @(idx),
             };
}

- (void) addTrackObservers:(AudioTrack*)playerItem
{
    NSKeyValueObservingOptions options = NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew;
    [playerItem addObserver:self forKeyPath:@"status" options:options context:&kPlayerItemStatusContext];
    [playerItem addObserver:self forKeyPath:@"duration" options:options context:&kPlayerItemDurationContext];
    [playerItem addObserver:self forKeyPath:@"loadedTimeRanges" options:options context:&kPlayerItemTimeRangesContext];

    // We don't need this one because we get the currentItem notification from the queue.
    // But we will wire it up anyway...
    NSNotificationCenter* listener = [NSNotificationCenter defaultCenter];
    [listener addObserver:self selector:@selector(playerItemDidReachEnd:) name:AVPlayerItemDidPlayToEndTimeNotification object:playerItem];
    // Subscribe to the AVPlayerItem's PlaybackStalledNotification notification.
    [listener addObserver:self selector:@selector(itemStalledPlaying:) name:AVPlayerItemPlaybackStalledNotification object:playerItem];

    [self onStatus:RMXSTATUS_ITEM_ADDED trackId:playerItem.trackId param:[playerItem toDict]];
    [self onStatus:RMXSTATUS_LOADING trackId:playerItem.trackId param:nil];
}

- (void) queuePlayerCleared:(NSNotification*) notification
{
    _isReplacingItems = NO;
    NSLog(@"RmxAudioPlayer, queuePlayerCleared");
    [self onStatus:RMXSTATUS_PLAYLIST_CLEARED trackId:@"INVALID" param:nil];
}

- (void) removeTrackObservers:(AudioTrack*)playerItem
{
    [playerItem removeObserver:self forKeyPath:@"status"];
    [playerItem removeObserver:self forKeyPath:@"duration"];
    [playerItem removeObserver:self forKeyPath:@"loadedTimeRanges"];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemDidPlayToEndTimeNotification object:playerItem];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemPlaybackStalledNotification object:playerItem];

    [self onStatus:RMXSTATUS_ITEM_REMOVED trackId:playerItem.trackId param:[playerItem toDict]];
}

- (void) activateAudioSession
{
    NSError *categoryError = nil;
    AVAudioSession* avSession = [AVAudioSession sharedInstance];

    // If no devices are connected, play audio through the default speaker (rather than the earpiece).
    AVAudioSessionCategoryOptions options = AVAudioSessionCategoryOptionDefaultToSpeaker;

    // If both Bluetooth streaming options are enabled, the low quality stream is preferred; enable A2DP only.
    if (@available(iOS 10.0, *)) {
        options |= AVAudioSessionCategoryOptionAllowBluetoothA2DP;
    } else {
        options |= AVAudioSessionCategoryOptionAllowBluetooth;
    }

    [avSession setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:options error:&categoryError];
    if (categoryError) {
        NSLog(@"Error setting category! %@", [categoryError description]);
    }

    NSError *activationError = nil;
    BOOL success = [[AVAudioSession sharedInstance] setActive:YES error:&activationError];

    if (!success) {
        if (activationError) {
            NSLog(@"Could not activate audio session. %@", [activationError localizedDescription]);
        } else {
            NSLog(@"audio session could not be activated!");
        }
    }
}

/**
 * Register the listener for pause and resume events.
 */
- (void) observeLifeCycle
{
    NSNotificationCenter* listener = [NSNotificationCenter defaultCenter];

    // These aren't really needed. the AVQueuePlayer handles this for us.
    // [listener addObserver:self selector:@selector(handleEnterBackground) name:UIApplicationDidEnterBackgroundNotification object:nil];
    // [listener addObserver:self selector:@selector(handleEnterForeground) name:UIApplicationWillEnterForegroundNotification object:nil];

    // We do need these.
    [listener addObserver:self selector:@selector(handleAudioSessionInterruption:) name:AVAudioSessionInterruptionNotification object:[AVAudioSession sharedInstance]];
    [listener addObserver:self selector:@selector(viewWillDisappear:) name:CDVViewWillDisappearNotification object:nil];

    // Listen to when the queue player tells us it emptied the items list
    [listener addObserver:self selector:@selector(queuePlayerCleared:) name:AVBidirectionalQueueCleared object:[self avQueuePlayer]];
}

- (void) viewWillDisappear:(NSNotification*)notification
{
    // For now, just capture it and log, and see when it triggers,
    // because that would seem to indicate the app closing in this case wouldn't it?
    NSLog(@"RmxAudioPlayer: viewWillDisappear");
    [self onStatus:RMXSTATUS_VIEWDISAPPEAR trackId:@"WINDOW" param:nil];
}

- (NSDictionary*)createErrorWithCode:(RmxAudioErrorType)code message:(NSString*)message
{
    NSString* finalMessage = message ? message : @"";

    return @{
             @"code": @(code),
             @"message": finalMessage
             };
}

- (void) onStatus:(RmxAudioStatusMessage)what trackId:(NSString*)trackId param:(NSObject*)param
{
    if (self.statusCallbackId != nil) {
        NSMutableDictionary* status = [NSMutableDictionary dictionary];
        status[@"msgType"] = @(what);
        // in the error case contains a dict with "code" and "message", otherwise a NSNumber
        status[@"value"] = param;
        status[@"trackId"] = trackId;

        NSMutableDictionary* dict = [NSMutableDictionary dictionary];
        dict[@"action"] = @"status";
        dict[@"status"] = status;

        CDVPluginResult* result = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsDictionary:dict];
        [result setKeepCallbackAsBool:YES]; // hold on to this.
        [self.commandDelegate sendPluginResult:result callbackId:self.statusCallbackId];
    }
}

/**
 *
 * Cleanup
 *
 *
 *
 *
 *
 *
 *
 *
 */

- (void) deregisterMusicControlsEventListener {
    // We don't use the remote control, and no need to remove observer on
    // NSNotificationCenter, that is done automatically
    // [[UIApplication sharedApplication] endReceivingRemoteControlEvents];
    // [[NSNotificationCenter defaultCenter] removeObserver:self name:@"receivedEvent" object:nil];

    MPRemoteCommandCenter *commandCenter = [MPRemoteCommandCenter sharedCommandCenter];
    [commandCenter.playCommand removeTarget:self];
    [commandCenter.pauseCommand removeTarget:self];
    [commandCenter.nextTrackCommand removeTarget:self];
    [commandCenter.previousTrackCommand removeTarget:self];
    [commandCenter.togglePlayPauseCommand removeTarget:self];

    // if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_9_0) {
    if (@available(iOS 9.0, *)) {
        [commandCenter.changePlaybackPositionCommand setEnabled:false];
        [commandCenter.changePlaybackPositionCommand removeTarget:self action:NULL];
    }

    _commandCenterRegistered = NO;
}

- (void) onMemoryWarning
{
    // override to remove caches, etc
    [super onMemoryWarning];

    // We can't really safely do this without alot of other changes to expect
    // the playlist to be empty.
    // Well, we've just destroyed everything, but ok.
    // [self removeAllTracks:YES];
    // NSLog(@"RmxAudioPlayer, queuePlayerCleared, MEMORY_WARNING");
    // [self onStatus:RMXSTATUS_PLAYLIST_CLEARED trackId:@"INVALID" param:@{@"reason": @"memory-warning"}];
}

- (void) onReset
{
    // Override to cancel any long-running requests when the WebView navigates or refreshes.
    [super onReset];
    [self releaseResources];
}

- (void) dealloc {
    // [super dealloc];
    [self releaseResources];
}

- (void) releaseResources {
    [_avQueuePlayer removeTimeObserver:_playbackTimeObserver];
    [_avQueuePlayer removeObserver:self forKeyPath:@"currentItem"];
    [_avQueuePlayer removeObserver:self forKeyPath:@"rate"];
    [self deregisterMusicControlsEventListener];

    // onReset or when killing app:
    if ([self.viewController isFirstResponder]) {
        [self.viewController resignFirstResponder];
    }
    [self removeAllTracks:NO];
    _avQueuePlayer = nil;

    _playbackTimeObserver = nil;
}

@end