path: root/SmartDeviceLink/SDLStreamingMediaLifecycleManager.m

//
//  SDLStreamingMediaLifecycleManager.m
//  SmartDeviceLink-iOS
//
//  Created by Muller, Alexander (A.) on 2/16/17.
//  Copyright © 2017 smartdevicelink. All rights reserved.
//

#import "SDLStreamingMediaLifecycleManager.h"

#import "SDLAbstractProtocol.h"
#import "SDLControlFramePayloadAudioStartServiceAck.h"
#import "SDLControlFramePayloadConstants.h"
#import "SDLControlFramePayloadNak.h"
#import "SDLControlFramePayloadVideoStartService.h"
#import "SDLControlFramePayloadVideoStartServiceAck.h"
#import "SDLDisplayCapabilities.h"
#import "SDLGenericResponse.h"
#import "SDLGetSystemCapability.h"
#import "SDLGetSystemCapabilityResponse.h"
#import "SDLGlobals.h"
#import "SDLFocusableItemLocator.h"
#import "SDLHMICapabilities.h"
#import "SDLImageResolution.h"
#import "SDLLogMacros.h"
#import "SDLNotificationConstants.h"
#import "SDLOnHMIStatus.h"
#import "SDLProtocolMessage.h"
#import "SDLRegisterAppInterfaceResponse.h"
#import "SDLRPCNotificationNotification.h"
#import "SDLRPCResponseNotification.h"
#import "SDLScreenParams.h"
#import "SDLStateMachine.h"
#import "SDLStreamingMediaConfiguration.h"
#import "SDLStreamingMediaManagerDataSource.h"
#import "SDLSystemCapability.h"
#import "SDLTouchManager.h"
#import "SDLH264VideoEncoder.h"
#import "SDLVideoStreamingCapability.h"
#import "SDLVideoStreamingCodec.h"
#import "SDLVideoStreamingFormat.h"
#import "SDLVideoStreamingProtocol.h"

#import "CVPixelBufferRef+SDLUtil.h"


NS_ASSUME_NONNULL_BEGIN

SDLAppState *const SDLAppStateInactive = @"AppInactive";
SDLAppState *const SDLAppStateActive = @"AppActive";

SDLVideoStreamState *const SDLVideoStreamStateStopped = @"VideoStreamStopped";
SDLVideoStreamState *const SDLVideoStreamStateStarting = @"VideoStreamStarting";
SDLVideoStreamState *const SDLVideoStreamStateReady = @"VideoStreamReady";
SDLVideoStreamState *const SDLVideoStreamStateShuttingDown = @"VideoStreamShuttingDown";

SDLAudioStreamState *const SDLAudioStreamStateStopped = @"AudioStreamStopped";
SDLAudioStreamState *const SDLAudioStreamStateStarting = @"AudioStreamStarting";
SDLAudioStreamState *const SDLAudioStreamStateReady = @"AudioStreamReady";
SDLAudioStreamState *const SDLAudioStreamStateShuttingDown = @"AudioStreamShuttingDown";

static NSUInteger const FramesToSendOnBackground = 30;

typedef void(^SDLVideoCapabilityResponseHandler)(SDLVideoStreamingCapability *_Nullable capability);


@interface SDLStreamingMediaLifecycleManager () <SDLVideoEncoderDelegate>

@property (weak, nonatomic) id<SDLConnectionManagerType> connectionManager;
@property (weak, nonatomic) SDLAbstractProtocol *protocol;

@property (assign, nonatomic, readonly, getter=isAppStateVideoStreamCapable) BOOL appStateVideoStreamCapable;
@property (assign, nonatomic, readonly, getter=isHmiStateAudioStreamCapable) BOOL hmiStateAudioStreamCapable;
@property (assign, nonatomic, readonly, getter=isHmiStateVideoStreamCapable) BOOL hmiStateVideoStreamCapable;

@property (assign, nonatomic, readwrite) BOOL restartVideoStream;
@property (strong, nonatomic, readwrite, nullable) SDLVideoStreamingFormat *videoFormat;

@property (strong, nonatomic, nullable) SDLH264VideoEncoder *videoEncoder;
@property (copy, nonatomic) NSDictionary<NSString *, id> *videoEncoderSettings;

@property (strong, nonatomic, readwrite) SDLStateMachine *appStateMachine;
@property (strong, nonatomic, readwrite) SDLStateMachine *videoStreamStateMachine;
@property (strong, nonatomic, readwrite) SDLStateMachine *audioStreamStateMachine;

@property (assign, nonatomic) CV_NULLABLE CVPixelBufferRef backgroundingPixelBuffer;

@property (assign, nonatomic) CMTime lastPresentationTimestamp;

@end


@implementation SDLStreamingMediaLifecycleManager

#pragma mark - Public
#pragma mark Lifecycle

- (instancetype)initWithConnectionManager:(id<SDLConnectionManagerType>)connectionManager configuration:(SDLStreamingMediaConfiguration *)configuration {
    self = [super init];
    if (!self) {
        return nil;
    }

    SDLLogV(@"Creating StreamingLifecycleManager");
    _connectionManager = connectionManager;

    if (configuration.window != nil) {
        _focusableItemManager = [[SDLFocusableItemLocator alloc] initWithWindow:configuration.window connectionManager:_connectionManager];
    }
    _touchManager = [[SDLTouchManager alloc] initWithHitTester:(id)_focusableItemManager];

    _videoEncoderSettings = configuration.customVideoEncoderSettings ?: SDLH264VideoEncoder.defaultVideoEncoderSettings;
    _requestedEncryptionType = configuration.maximumDesiredEncryption;
    _dataSource = configuration.dataSource;
    _screenSize = SDLDefaultScreenSize;
    _backgroundingPixelBuffer = NULL;
    _preferredFormatIndex = 0;
    _preferredResolutionIndex = 0;

    SDLAppState *initialState = SDLAppStateInactive;
    switch ([[UIApplication sharedApplication] applicationState]) {
        case UIApplicationStateActive: {
            initialState = SDLAppStateActive;
        } break;
        case UIApplicationStateInactive: // fallthrough
        case UIApplicationStateBackground: {
            initialState = SDLAppStateInactive;
        } break;
        default: break;
    }

    _appStateMachine = [[SDLStateMachine alloc] initWithTarget:self initialState:initialState states:[self.class sdl_appStateTransitionDictionary]];
    _videoStreamStateMachine = [[SDLStateMachine alloc] initWithTarget:self initialState:SDLVideoStreamStateStopped states:[self.class sdl_videoStreamStateTransitionDictionary]];
    _audioStreamStateMachine = [[SDLStateMachine alloc] initWithTarget:self initialState:SDLAudioStreamStateStopped states:[self.class sdl_audioStreamingStateTransitionDictionary]];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_didReceiveRegisterAppInterfaceResponse:) name:SDLDidReceiveRegisterAppInterfaceResponse object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_hmiLevelDidChange:) name:SDLDidChangeHMIStatusNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_appStateDidUpdate:) name:UIApplicationDidBecomeActiveNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_appStateDidUpdate:) name:UIApplicationWillResignActiveNotification object:nil];

    _lastPresentationTimestamp = kCMTimeInvalid;

    return self;
}

- (void)startWithProtocol:(SDLAbstractProtocol *)protocol {
    _protocol = protocol;

    if (![self.protocol.protocolDelegateTable containsObject:self]) {
        [self.protocol.protocolDelegateTable addObject:self];
    }
}

- (void)stop {
    SDLLogD(@"Stopping manager");
    [self sdl_stopAudioSession];
    [self sdl_stopVideoSession];

    self.restartVideoStream = NO;
    [self.audioStreamStateMachine transitionToState:SDLAudioStreamStateStopped];
    [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateStopped];
}

- (BOOL)sendVideoData:(CVImageBufferRef)imageBuffer {
    return [self sendVideoData:imageBuffer presentationTimestamp:kCMTimeInvalid];
}

- (BOOL)sendVideoData:(CVImageBufferRef)imageBuffer presentationTimestamp:(CMTime)presentationTimestamp {
    if (!self.isVideoConnected) {
        SDLLogW(@"Attempted to send video data, but not connected");
        return NO;
    } else if (!self.isAppStateVideoStreamCapable) {
        SDLLogW(@"Attempted to send video data, but app is not in the foreground");
        return NO;
    } else if (!self.isHmiStateVideoStreamCapable) {
        SDLLogW(@"Attempted to send video data, but the app is not in LIMITED or FULL HMI state");
        return NO;
    }

    /*
     * reject input image for following cases:
     * - presentation timestamp is not increasing
     * - app tries to send images while background images are shown
     */
    if (CMTIME_IS_VALID(self.lastPresentationTimestamp) && CMTIME_IS_VALID(presentationTimestamp)
        && CMTIME_COMPARE_INLINE(presentationTimestamp, <=, self.lastPresentationTimestamp)) {
        SDLLogW(@"The video data is out of date");
        return NO;
    }
    self.lastPresentationTimestamp = presentationTimestamp;

    SDLLogV(@"Sending data to video encoder");
    return [self.videoEncoder encodeFrame:imageBuffer presentationTimestamp:presentationTimestamp];
}

- (BOOL)sendAudioData:(NSData*)audioData {
    if (!self.isAudioConnected) {
        return NO;
    }

    SDLLogV(@"Sending raw audio data");
    if (self.isAudioEncrypted) {
        [self.protocol sendEncryptedRawData:audioData onService:SDLServiceTypeAudio];
    } else {
        [self.protocol sendRawData:audioData withServiceType:SDLServiceTypeAudio];
    }
    return YES;
}

#pragma mark Getters
- (BOOL)isAudioConnected {
    return [self.audioStreamStateMachine isCurrentState:SDLAudioStreamStateReady];
}

- (BOOL)isVideoConnected {
    return [self.videoStreamStateMachine isCurrentState:SDLVideoStreamStateReady];
}

- (BOOL)isVideoStreamingPaused {
    return !(self.isVideoConnected && self.isHmiStateVideoStreamCapable && self.isAppStateVideoStreamCapable);
}

- (CVPixelBufferPoolRef __nullable)pixelBufferPool {
    return self.videoEncoder.pixelBufferPool;
}

- (SDLAppState *)currentAppState {
    return self.appStateMachine.currentState;
}

- (SDLAudioStreamState *)currentAudioStreamState {
    return self.audioStreamStateMachine.currentState;
}

- (SDLVideoStreamState *)currentVideoStreamState {
    return self.videoStreamStateMachine.currentState;
}

#pragma mark - State Machines
#pragma mark App State
+ (NSDictionary<SDLState *, SDLAllowableStateTransitions *> *)sdl_appStateTransitionDictionary {
    return @{
             // Will go from Inactive to Active if coming from a Phone Call.
             // Will go from Inactive to IsRegainingActive if coming from Background.
             SDLAppStateInactive : @[SDLAppStateActive],
             SDLAppStateActive : @[SDLAppStateInactive]
             };
}

- (void)sdl_appStateDidUpdate:(NSNotification*)notification {
    if (notification.name == UIApplicationWillResignActiveNotification) {
        [self.appStateMachine transitionToState:SDLAppStateInactive];
    } else if (notification.name == UIApplicationDidBecomeActiveNotification) {
        [self.appStateMachine transitionToState:SDLAppStateActive];
    }
}

- (void)didEnterStateAppInactive {
    SDLLogD(@"App became inactive");
    if (!self.protocol) { return; }

    [self sdl_sendBackgroundFrames];
    [self.touchManager cancelPendingTouches];
    self.restartVideoStream = YES;
}

// Per Apple's guidelines: https://developer.apple.com/library/content/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/StrategiesforHandlingAppStateTransitions/StrategiesforHandlingAppStateTransitions.html
// We should be waiting to start any OpenGL drawing until UIApplicationDidBecomeActive is called.
- (void)didEnterStateAppActive {
    SDLLogD(@"App became active");
    if (!self.protocol) { return; }

    [self sdl_startVideoSession];
    [self sdl_startAudioSession];
}

#pragma mark Video Streaming
+ (NSDictionary<SDLState *, SDLAllowableStateTransitions *> *)sdl_videoStreamStateTransitionDictionary {
    return @{
             SDLVideoStreamStateStopped : @[SDLVideoStreamStateStarting],
             SDLVideoStreamStateStarting : @[SDLVideoStreamStateStopped, SDLVideoStreamStateReady],
             SDLVideoStreamStateReady : @[SDLVideoStreamStateShuttingDown, SDLVideoStreamStateStopped],
             SDLVideoStreamStateShuttingDown : @[SDLVideoStreamStateStopped]
             };
}

- (void)didEnterStateVideoStreamStopped {
    SDLLogD(@"Video stream stopped");
    _videoEncrypted = NO;
    _videoFormat = nil;

    if (_videoEncoder != nil) {
        [_videoEncoder stop];
        _videoEncoder = nil;
    }

    [[NSNotificationCenter defaultCenter] postNotificationName:SDLVideoStreamDidStopNotification object:nil];

    if (self.shouldRestartVideoStream) {
        self.restartVideoStream = NO;
        [self sdl_startVideoSession];
    }
}

- (void)didEnterStateVideoStreamStarting {
    SDLLogD(@"Video stream starting");
    self.restartVideoStream = NO;

    __weak typeof(self) weakSelf = self;
    [self sdl_requestVideoCapabilities:^(SDLVideoStreamingCapability * _Nullable capability) {
        SDLLogD(@"Received video capability response");
        SDLLogV(@"Capability: %@", capability);

        if (capability != nil) {
            // If we got a response, get our preferred formats and resolutions
            weakSelf.preferredFormats = capability.supportedFormats;
            weakSelf.preferredResolutions = @[capability.preferredResolution];

            if (weakSelf.dataSource != nil) {
                SDLLogV(@"Calling data source for modified preferred formats and resolutions");
                weakSelf.preferredFormats = [weakSelf.dataSource preferredVideoFormatOrderFromHeadUnitPreferredOrder:weakSelf.preferredFormats];
                weakSelf.preferredResolutions = [weakSelf.dataSource resolutionFromHeadUnitPreferredResolution:weakSelf.preferredResolutions.firstObject];
            }

            if (weakSelf.focusableItemManager != nil) {
                weakSelf.focusableItemManager.enableHapticDataRequests = capability.hapticSpatialDataSupported.boolValue;
            }

            SDLLogD(@"Got specialized video capabilites, preferred formats: %@, resolutions: %@ haptics enabled %@", weakSelf.preferredFormats, weakSelf.preferredResolutions, (capability.hapticSpatialDataSupported.boolValue ? @"YES" : @"NO"));
        } else {
            // If we can't get capabilities, we're assuming it's H264 RAW at whatever the display capabilities said in the RAIR. We also aren't going to call the data source because they have no options.
            SDLVideoStreamingFormat *format = [[SDLVideoStreamingFormat alloc] initWithCodec:SDLVideoStreamingCodecH264 protocol:SDLVideoStreamingProtocolRAW];
            SDLImageResolution *resolution = [[SDLImageResolution alloc] initWithWidth:weakSelf.screenSize.width height:weakSelf.screenSize.height];
            weakSelf.preferredFormats = @[format];
            weakSelf.preferredResolutions = @[resolution];

            if (weakSelf.focusableItemManager != nil) {
                weakSelf.focusableItemManager.enableHapticDataRequests = NO;
            }

            SDLLogD(@"Using generic video capabilites, preferred formats: %@, resolutions: %@, haptics disabled", weakSelf.preferredFormats, weakSelf.preferredResolutions);
        }

        [self sdl_sendVideoStartService];
    }];
}

- (void)didEnterStateVideoStreamReady {
    SDLLogD(@"Video stream ready");
    // TODO: What if it isn't nil, is it even possible for it to not be nil?
    if (self.videoEncoder == nil) {
        NSError* error = nil;
        NSAssert(self.videoFormat != nil, @"No video format is known, but it must be if we got a protocol start service response");

        SDLLogD(@"Attempting to create video encoder");
        self.videoEncoder = [[SDLH264VideoEncoder alloc] initWithProtocol:self.videoFormat.protocol dimensions:self.screenSize properties:self.videoEncoderSettings delegate:self error:&error];

        if (error || self.videoEncoder == nil) {
            SDLLogE(@"Could not create a video encoder: %@", error);
            [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateStopped];
            return;
        }

        if (!self.backgroundingPixelBuffer) {
            CVPixelBufferRef backgroundingPixelBuffer = [self.videoEncoder newPixelBuffer];
            if (CVPixelBufferAddText(backgroundingPixelBuffer, @"") == NO) {
                SDLLogE(@"Could not create a backgrounding frame");
                [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateStopped];
                return;
            }

            self.backgroundingPixelBuffer = backgroundingPixelBuffer;
        }
        self.lastPresentationTimestamp = kCMTimeInvalid;
    }

    [[NSNotificationCenter defaultCenter] postNotificationName:SDLVideoStreamDidStartNotification object:nil];
}

- (void)didEnterStateVideoStreamShuttingDown {
    SDLLogD(@"Video stream shutting down");
    [self.protocol endServiceWithType:SDLServiceTypeVideo];
}

#pragma mark Audio
+ (NSDictionary<SDLState *, SDLAllowableStateTransitions *> *)sdl_audioStreamingStateTransitionDictionary {
    return @{
             SDLAudioStreamStateStopped : @[SDLAudioStreamStateStarting],
             SDLAudioStreamStateStarting : @[SDLAudioStreamStateStopped, SDLAudioStreamStateReady],
             SDLAudioStreamStateReady : @[SDLAudioStreamStateShuttingDown, SDLAudioStreamStateStopped],
             SDLAudioStreamStateShuttingDown : @[SDLAudioStreamStateStopped]
             };
}

- (void)didEnterStateAudioStreamStopped {
    SDLLogD(@"Audio stream stopped");
    _audioEncrypted = NO;

    [[NSNotificationCenter defaultCenter] postNotificationName:SDLAudioStreamDidStopNotification object:nil];
}

- (void)didEnterStateAudioStreamStarting {
    SDLLogD(@"Audio stream starting");
    if (self.requestedEncryptionType != SDLStreamingEncryptionFlagNone) {
        [self.protocol startSecureServiceWithType:SDLServiceTypeAudio payload:nil completionHandler:^(BOOL success, NSError * _Nonnull error) {
            if (error) {
                SDLLogE(@"TLS setup error: %@", error);
                [self.audioStreamStateMachine transitionToState:SDLAudioStreamStateStopped];
            }
        }];
    } else {
        [self.protocol startServiceWithType:SDLServiceTypeAudio payload:nil];
    }
}

- (void)didEnterStateAudioStreamReady {
    SDLLogD(@"Audio stream ready");
    [[NSNotificationCenter defaultCenter] postNotificationName:SDLAudioStreamDidStartNotification object:nil];
}

- (void)didEnterStateAudioStreamShuttingDown {
    SDLLogD(@"Audio stream shutting down");
    [self.protocol endServiceWithType:SDLServiceTypeAudio];
}

#pragma mark - SDLProtocolListener
#pragma mark Video / Audio Start Service ACK

- (void)handleProtocolStartServiceACKMessage:(SDLProtocolMessage *)startServiceACK {
    switch (startServiceACK.header.serviceType) {
        case SDLServiceTypeAudio: {
            [self sdl_handleAudioStartServiceAck:startServiceACK];
        } break;
        case SDLServiceTypeVideo: {
            [self sdl_handleVideoStartServiceAck:startServiceACK];
        } break;
        default: break;
    }
}

- (void)sdl_handleAudioStartServiceAck:(SDLProtocolMessage *)audioStartServiceAck {
    SDLLogD(@"Audio service started");
    _audioEncrypted = audioStartServiceAck.header.encrypted;

    SDLControlFramePayloadAudioStartServiceAck *audioAckPayload = [[SDLControlFramePayloadAudioStartServiceAck alloc] initWithData:audioStartServiceAck.payload];
    SDLLogV(@"ACK: %@", audioAckPayload);

    if (audioAckPayload.mtu != SDLControlFrameInt64NotFound) {
        [[SDLGlobals sharedGlobals] setDynamicMTUSize:audioAckPayload.mtu forServiceType:SDLServiceTypeAudio];
    }

    [self.audioStreamStateMachine transitionToState:SDLAudioStreamStateReady];
}

- (void)sdl_handleVideoStartServiceAck:(SDLProtocolMessage *)videoStartServiceAck {
    SDLLogD(@"Video service started");
    _videoEncrypted = videoStartServiceAck.header.encrypted;

    SDLControlFramePayloadVideoStartServiceAck *videoAckPayload = [[SDLControlFramePayloadVideoStartServiceAck alloc] initWithData:videoStartServiceAck.payload];
    SDLLogV(@"ACK: %@", videoAckPayload);

    if (videoAckPayload.mtu != SDLControlFrameInt64NotFound) {
        [[SDLGlobals sharedGlobals] setDynamicMTUSize:videoAckPayload.mtu forServiceType:SDLServiceTypeVideo];
    }

    // This is the definitive screen size that will be used
    if (videoAckPayload.height != SDLControlFrameInt32NotFound && videoAckPayload.width != SDLControlFrameInt32NotFound) {
        _screenSize = CGSizeMake(videoAckPayload.width, videoAckPayload.height);
    } // else we are using the screen size we got from the RAIR earlier

    // Figure out the definitive format that will be used. If the protocol / codec weren't passed in the payload, it's probably a system that doesn't support those properties, which also means it's a system that requires H.264 RAW encoding
    self.videoFormat = [[SDLVideoStreamingFormat alloc] init];
    self.videoFormat.codec = videoAckPayload.videoCodec ?: SDLVideoStreamingCodecH264;
    self.videoFormat.protocol = videoAckPayload.videoProtocol ?: SDLVideoStreamingProtocolRAW;

    [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateReady];
}

#pragma mark Video / Audio Start Service NAK

- (void)handleProtocolStartServiceNAKMessage:(SDLProtocolMessage *)startServiceNAK {
    switch (startServiceNAK.header.serviceType) {
        case SDLServiceTypeAudio: {
            [self sdl_handleAudioStartServiceNak:startServiceNAK];
        } break;
        case SDLServiceTypeVideo: {
            [self sdl_handleVideoStartServiceNak:startServiceNAK];
        }
        default: break;
    }
}

- (void)sdl_handleVideoStartServiceNak:(SDLProtocolMessage *)videoStartServiceNak {
    SDLLogW(@"Video service failed to start due to NAK");
    SDLControlFramePayloadNak *nakPayload = [[SDLControlFramePayloadNak alloc] initWithData:videoStartServiceNak.payload];
    SDLLogD(@"NAK: %@", videoStartServiceNak);

    // If we have no payload rejected params, we don't know what to do to retry, so we'll just stop and maybe cry
    if (nakPayload.rejectedParams.count == 0) {
        [self sdl_transitionToStoppedState:SDLServiceTypeVideo];
        return;
    }

    // If height and/or width was rejected, and we have another resolution to try, advance our counter to try another resolution
    if (([nakPayload.rejectedParams containsObject:[NSString stringWithUTF8String:SDLControlFrameHeightKey]]
         || [nakPayload.rejectedParams containsObject:[NSString stringWithUTF8String:SDLControlFrameWidthKey]])) {
        self.preferredResolutionIndex++;
    }

    if (([nakPayload.rejectedParams containsObject:[NSString stringWithUTF8String:SDLControlFrameVideoCodecKey]]
         || [nakPayload.rejectedParams containsObject:[NSString stringWithUTF8String:SDLControlFrameVideoProtocolKey]])) {
        self.preferredFormatIndex++;
    }

    [self sdl_sendVideoStartService];
}

- (void)sdl_handleAudioStartServiceNak:(SDLProtocolMessage *)audioStartServiceNak {
    SDLLogW(@"Audio service failed to start due to NAK");
    [self sdl_transitionToStoppedState:SDLServiceTypeAudio];
}

#pragma mark Video / Audio End Service

- (void)handleProtocolEndServiceACKMessage:(SDLProtocolMessage *)endServiceACK {
    SDLLogD(@"%@ service ended", (endServiceACK.header.serviceType == SDLServiceTypeVideo ? @"Video" : @"Audio"));
    [self sdl_transitionToStoppedState:endServiceACK.header.serviceType];
}

- (void)handleProtocolEndServiceNAKMessage:(SDLProtocolMessage *)endServiceNAK {
    SDLLogW(@"%@ service ended with end service NAK", (endServiceNAK.header.serviceType == SDLServiceTypeVideo ? @"Video" : @"Audio"));
    [self sdl_transitionToStoppedState:endServiceNAK.header.serviceType];
}

#pragma mark - SDLVideoEncoderDelegate

- (void)videoEncoder:(SDLH264VideoEncoder *)encoder hasEncodedFrame:(NSData *)encodedVideo {
    SDLLogV(@"Video encoder encoded frame, sending data");
    // Do we care about app state here? I don't think so…
    BOOL capableVideoStreamState = [self.videoStreamStateMachine isCurrentState:SDLVideoStreamStateReady];

    if (self.isHmiStateVideoStreamCapable && capableVideoStreamState) {
        if (self.isVideoEncrypted) {
            [self.protocol sendEncryptedRawData:encodedVideo onService:SDLServiceTypeVideo];
        } else {
            [self.protocol sendRawData:encodedVideo withServiceType:SDLServiceTypeVideo];
        }
    }
}

#pragma mark - SDL RPC Notification callbacks

- (void)sdl_didReceiveRegisterAppInterfaceResponse:(SDLRPCResponseNotification *)notification {
    NSAssert([notification.response isKindOfClass:[SDLRegisterAppInterfaceResponse class]], @"A notification was sent with an unanticipated object");
    if (![notification.response isKindOfClass:[SDLRegisterAppInterfaceResponse class]]) {
        return;
    }

    SDLLogD(@"Received Register App Interface");
    SDLRegisterAppInterfaceResponse* registerResponse = (SDLRegisterAppInterfaceResponse*)notification.response;

    SDLLogV(@"Determining whether streaming is supported");
    _streamingSupported = registerResponse.hmiCapabilities.videoStreaming ? registerResponse.hmiCapabilities.videoStreaming.boolValue : registerResponse.displayCapabilities.graphicSupported.boolValue;

    if (!self.isStreamingSupported) {
        SDLLogE(@"Graphics are not supported on this head unit. We are are assuming screen size is also unavailable and exiting.");
        return;
    }

    SDLImageResolution* resolution = registerResponse.displayCapabilities.screenParams.resolution;
    if (resolution != nil) {
        _screenSize = CGSizeMake(resolution.resolutionWidth.floatValue,
                                 resolution.resolutionHeight.floatValue);
    } else {
        _screenSize = SDLDefaultScreenSize;
    }

    SDLLogD(@"Determined base screen size on display capabilities: %@", NSStringFromCGSize(_screenSize));
}

- (void)sdl_hmiLevelDidChange:(SDLRPCNotificationNotification *)notification {
    NSAssert([notification.notification isKindOfClass:[SDLOnHMIStatus class]], @"A notification was sent with an unanticipated object");
    if (![notification.notification isKindOfClass:[SDLOnHMIStatus class]]) {
        return;
    }

    SDLOnHMIStatus *hmiStatus = (SDLOnHMIStatus*)notification.notification;
    SDLLogD(@"HMI level changed from level %@ to level %@", self.hmiLevel, hmiStatus.hmiLevel);
    self.hmiLevel = hmiStatus.hmiLevel;

    if (self.isHmiStateVideoStreamCapable) {
        [self sdl_startVideoSession];
    } else {
        [self sdl_stopVideoSession];
    }

    if (self.isHmiStateAudioStreamCapable) {
        [self sdl_startAudioSession];
    } else {
        [self sdl_stopAudioSession];
    }
}


#pragma mark - Streaming session helpers

- (void)sdl_startVideoSession {
    SDLLogV(@"Attempting to start video session");

    if (!self.isStreamingSupported) {
        SDLLogV(@"Streaming is not supported. Video start service request will not be sent.");
        return;
    }

    if (self.shouldRestartVideoStream && [self.videoStreamStateMachine isCurrentState:SDLVideoStreamStateReady]) {
        SDLLogV(@"Video needs to be restarted. Stopping video stream.");
        [self sdl_stopVideoSession];
        return;
    }

    if ([self.videoStreamStateMachine isCurrentState:SDLVideoStreamStateStopped]
          && self.isHmiStateVideoStreamCapable) {
        [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateStarting];
    } else {
        SDLLogE(@"Unable to send video start service request\n"
                "Video State must be in state STOPPED: %@\n"
                "HMI state must be LIMITED or FULL: %@\n",
                self.videoStreamStateMachine.currentState, self.hmiLevel);
    }
}

- (void)sdl_startAudioSession {
    SDLLogV(@"Attempting to start audio session");
    if (!self.isStreamingSupported) {
        return;
    }

    if ([self.audioStreamStateMachine isCurrentState:SDLAudioStreamStateStopped]
        && self.isHmiStateAudioStreamCapable) {
        [self.audioStreamStateMachine transitionToState:SDLAudioStreamStateStarting];
    }
}

- (void)sdl_stopVideoSession {
    SDLLogV(@"Attempting to stop video session");
    if (!self.isStreamingSupported) {
        return;
    }

    if (self.isVideoConnected) {
        [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateShuttingDown];
    }
}

- (void)sdl_stopAudioSession {
    SDLLogV(@"Attempting to stop audio session");
    if (!self.isStreamingSupported) {
        return;
    }

    if (self.isAudioConnected) {
        [self.audioStreamStateMachine transitionToState:SDLAudioStreamStateShuttingDown];
    }
}

- (void)sdl_transitionToStoppedState:(SDLServiceType)serviceType {
    switch (serviceType) {
        case SDLServiceTypeAudio:
            [self.audioStreamStateMachine transitionToState:SDLAudioStreamStateStopped];
            break;
        case SDLServiceTypeVideo:
            [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateStopped];
            break;
        default:
            break;
    }
}

- (void)sdl_sendBackgroundFrames {
    SDLLogV(@"Attempting to send background frames");
    if (!self.backgroundingPixelBuffer) {
        SDLLogW(@"No background pixel buffer, unable to send background frames");
        return;
    }

    int32_t timeRate = 30;
    if (self.videoEncoderSettings[(__bridge NSString *)kVTCompressionPropertyKey_ExpectedFrameRate] != nil) {
        timeRate = ((NSNumber *)self.videoEncoderSettings[(__bridge NSString *)kVTCompressionPropertyKey_ExpectedFrameRate]).intValue;
    }

    const CMTime interval = CMTimeMake(1, timeRate);
    for (int frameCount = 0; frameCount < FramesToSendOnBackground; frameCount++) {
        if (CMTIME_IS_VALID(self.lastPresentationTimestamp)) {
            self.lastPresentationTimestamp = CMTimeAdd(self.lastPresentationTimestamp, interval);
            [self.videoEncoder encodeFrame:self.backgroundingPixelBuffer presentationTimestamp:self.lastPresentationTimestamp];
        } else {
            [self.videoEncoder encodeFrame:self.backgroundingPixelBuffer];
        }
    }
}

- (void)sdl_requestVideoCapabilities:(SDLVideoCapabilityResponseHandler)responseHandler {
    SDLLogD(@"Requesting video capabilities");
    SDLGetSystemCapability *getVideoCapabilityRequest = [[SDLGetSystemCapability alloc] initWithType:SDLSystemCapabilityTypeVideoStreaming];

    [self.connectionManager sendManagerRequest:getVideoCapabilityRequest withResponseHandler:^(__kindof SDLRPCRequest * _Nullable request, __kindof SDLRPCResponse * _Nullable response, NSError * _Nullable error) {
        if (!response.success || [response isMemberOfClass:SDLGenericResponse.class]) {
            SDLLogW(@"Video capabilities response failed: %@", error);
            responseHandler(nil);
            BLOCK_RETURN;
        }

        SDLVideoStreamingCapability *videoCapability = ((SDLGetSystemCapabilityResponse *)response).systemCapability.videoStreamingCapability;
        SDLLogD(@"Video capabilities response received: %@", videoCapability);
        responseHandler(videoCapability);
    }];
}

/**
 Pull the current format / resolution out of our preferred resolutions and craft a start video service payload out of it, then send a start service. If the format isn't one that we support, we're going to try the next format.
 */
- (void)sdl_sendVideoStartService {
    SDLLogV(@"Attempting to find preferred format");
    while (self.preferredFormatIndex < self.preferredFormats.count) {
        if (![self.supportedFormats containsObject:self.preferredFormats[self.preferredFormatIndex]]) {
            self.preferredFormatIndex++;
        } else {
            SDLLogV(@"Preferred format index found: %lu", self.preferredFormatIndex);
            break;
        }
    }

    // If this fails we have no known formats to use
    if (self.preferredFormatIndex >= self.preferredFormats.count
        || self.preferredResolutionIndex >= self.preferredResolutions.count) {
        SDLLogE(@"No preferred format or no preferred resolution found that works: format index %lu, resolution index %lu", self.preferredFormatIndex, self.preferredResolutionIndex);
        [self sdl_transitionToStoppedState:SDLServiceTypeVideo];
        return;
    }

    SDLVideoStreamingFormat *preferredFormat = self.preferredFormats[self.preferredFormatIndex];
    SDLImageResolution *preferredResolution = self.preferredResolutions[self.preferredResolutionIndex];

    SDLControlFramePayloadVideoStartService *startVideoPayload = [[SDLControlFramePayloadVideoStartService alloc] initWithVideoHeight:preferredResolution.resolutionHeight.intValue width:preferredResolution.resolutionWidth.intValue protocol:preferredFormat.protocol codec:preferredFormat.codec];

    // Decide if we need to start a secure service or not
    if (self.requestedEncryptionType != SDLStreamingEncryptionFlagNone) {
        SDLLogD(@"Sending secure video start service with payload: %@", startVideoPayload);
        [self.protocol startSecureServiceWithType:SDLServiceTypeVideo payload:startVideoPayload.data completionHandler:^(BOOL success, NSError *error) {
            if (error) {
                SDLLogE(@"TLS setup error: %@", error);
                [self.videoStreamStateMachine transitionToState:SDLVideoStreamStateStopped];
            }
        }];
    } else {
        SDLLogD(@"Sending insecure video start service with payload: %@", startVideoPayload);
        [self.protocol startServiceWithType:SDLServiceTypeVideo payload:startVideoPayload.data];
    }
}


#pragma mark Getters

- (BOOL)isAppStateVideoStreamCapable {
    return [self.appStateMachine isCurrentState:SDLAppStateActive];
}

- (BOOL)isHmiStateAudioStreamCapable {
    return YES;
}

- (BOOL)isHmiStateVideoStreamCapable {
    return [self.hmiLevel isEqualToEnum:SDLHMILevelLimited] || [self.hmiLevel isEqualToEnum:SDLHMILevelFull];
}

- (NSArray<SDLVideoStreamingFormat *> *)supportedFormats {
    SDLVideoStreamingFormat *h264raw = [[SDLVideoStreamingFormat alloc] initWithCodec:SDLVideoStreamingCodecH264 protocol:SDLVideoStreamingProtocolRAW];
    SDLVideoStreamingFormat *h264rtp = [[SDLVideoStreamingFormat alloc] initWithCodec:SDLVideoStreamingCodecH264 protocol:SDLVideoStreamingProtocolRTP];
    
    return @[h264raw, h264rtp];
}

@end

NS_ASSUME_NONNULL_END