webrtc/examples/objc/AppRTCDemo/ARDAppClient.m - platform/external/webrtc - Git at Google

 /*
  *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 #import "ARDAppClient+Internal.h"

 #if defined(WEBRTC_IOS)
 #import "RTCAVFoundationVideoSource.h"
 #endif
 #import "RTCFileLogger.h"
 #import "RTCICEServer.h"
 #import "RTCLogging.h"
 #import "RTCMediaConstraints.h"
 #import "RTCMediaStream.h"
 #import "RTCPair.h"
 #import "RTCPeerConnectionInterface.h"
 #import "RTCVideoCapturer.h"

 #import "ARDAppEngineClient.h"
 #import "ARDCEODTURNClient.h"
 #import "ARDJoinResponse.h"
 #import "ARDMessageResponse.h"
 #import "ARDSDPUtils.h"
 #import "ARDSignalingMessage.h"
 #import "ARDUtilities.h"
 #import "ARDWebSocketChannel.h"
 #import "RTCICECandidate+JSON.h"
 #import "RTCSessionDescription+JSON.h"


 static NSString * const kARDDefaultSTUNServerUrl =
     @"stun:stun.l.google.com:19302";
 // TODO(tkchin): figure out a better username for CEOD statistics.
 static NSString * const kARDTurnRequestUrl =
     @"https://computeengineondemand.appspot.com"
     @"/turn?username=iapprtc&key=4080218913";

 static NSString * const kARDAppClientErrorDomain = @"ARDAppClient";
 static NSInteger const kARDAppClientErrorUnknown = -1;
 static NSInteger const kARDAppClientErrorRoomFull = -2;
 static NSInteger const kARDAppClientErrorCreateSDP = -3;
 static NSInteger const kARDAppClientErrorSetSDP = -4;
 static NSInteger const kARDAppClientErrorInvalidClient = -5;
 static NSInteger const kARDAppClientErrorInvalidRoom = -6;

 @implementation ARDAppClient {
   RTCFileLogger *_fileLogger;
 }

 @synthesize delegate = _delegate;
 @synthesize state = _state;
 @synthesize roomServerClient = _roomServerClient;
 @synthesize channel = _channel;
 @synthesize turnClient = _turnClient;
 @synthesize peerConnection = _peerConnection;
 @synthesize factory = _factory;
 @synthesize messageQueue = _messageQueue;
 @synthesize isTurnComplete = _isTurnComplete;
 @synthesize hasReceivedSdp  = _hasReceivedSdp;
 @synthesize roomId = _roomId;
 @synthesize clientId = _clientId;
 @synthesize isInitiator = _isInitiator;
 @synthesize iceServers = _iceServers;
 @synthesize webSocketURL = _websocketURL;
 @synthesize webSocketRestURL = _websocketRestURL;
 @synthesize defaultPeerConnectionConstraints =
     _defaultPeerConnectionConstraints;

 - (instancetype)init {
   if (self = [super init]) {
     _roomServerClient = [[ARDAppEngineClient alloc] init];
     NSURL *turnRequestURL = [NSURL URLWithString:kARDTurnRequestUrl];
     _turnClient = [[ARDCEODTURNClient alloc] initWithURL:turnRequestURL];
     [self configure];
   }
   return self;
 }

 - (instancetype)initWithDelegate:(id<ARDAppClientDelegate>)delegate {
   if (self = [super init]) {
     _roomServerClient = [[ARDAppEngineClient alloc] init];
     _delegate = delegate;
     NSURL *turnRequestURL = [NSURL URLWithString:kARDTurnRequestUrl];
     _turnClient = [[ARDCEODTURNClient alloc] initWithURL:turnRequestURL];
     [self configure];
   }
   return self;
 }

 // TODO(tkchin): Provide signaling channel factory interface so we can recreate
 // channel if we need to on network failure. Also, make this the default public
 // constructor.
 - (instancetype)initWithRoomServerClient:(id<ARDRoomServerClient>)rsClient
                         signalingChannel:(id<ARDSignalingChannel>)channel
                               turnClient:(id<ARDTURNClient>)turnClient
                                 delegate:(id<ARDAppClientDelegate>)delegate {
   NSParameterAssert(rsClient);
   NSParameterAssert(channel);
   NSParameterAssert(turnClient);
   if (self = [super init]) {
     _roomServerClient = rsClient;
     _channel = channel;
     _turnClient = turnClient;
     _delegate = delegate;
     [self configure];
   }
   return self;
 }

 - (void)configure {
   _factory = [[RTCPeerConnectionFactory alloc] init];
   _messageQueue = [NSMutableArray array];
   _iceServers = [NSMutableArray arrayWithObject:[self defaultSTUNServer]];
   _fileLogger = [[RTCFileLogger alloc] init];
   [_fileLogger start];
 }

 - (void)dealloc {
   [self disconnect];
 }

 - (void)setState:(ARDAppClientState)state {
   if (_state == state) {
     return;
   }
   _state = state;
   [_delegate appClient:self didChangeState:_state];
 }

 - (void)connectToRoomWithId:(NSString *)roomId
                     options:(NSDictionary *)options {
   NSParameterAssert(roomId.length);
   NSParameterAssert(_state == kARDAppClientStateDisconnected);
   self.state = kARDAppClientStateConnecting;

   // Request TURN.
   __weak ARDAppClient *weakSelf = self;
   [_turnClient requestServersWithCompletionHandler:^(NSArray *turnServers,
                                                      NSError *error) {
     if (error) {
       RTCLogError("Error retrieving TURN servers: %@",
                   error.localizedDescription);
     }
     ARDAppClient *strongSelf = weakSelf;
     [strongSelf.iceServers addObjectsFromArray:turnServers];
     strongSelf.isTurnComplete = YES;
     [strongSelf startSignalingIfReady];
   }];

   // Join room on room server.
   [_roomServerClient joinRoomWithRoomId:roomId
       completionHandler:^(ARDJoinResponse *response, NSError *error) {
     ARDAppClient *strongSelf = weakSelf;
     if (error) {
       [strongSelf.delegate appClient:strongSelf didError:error];
       return;
     }
     NSError *joinError =
         [[strongSelf class] errorForJoinResultType:response.result];
     if (joinError) {
       RTCLogError(@"Failed to join room:%@ on room server.", roomId);
       [strongSelf disconnect];
       [strongSelf.delegate appClient:strongSelf didError:joinError];
       return;
     }
     RTCLog(@"Joined room:%@ on room server.", roomId);
     strongSelf.roomId = response.roomId;
     strongSelf.clientId = response.clientId;
     strongSelf.isInitiator = response.isInitiator;
     for (ARDSignalingMessage *message in response.messages) {
       if (message.type == kARDSignalingMessageTypeOffer ||
           message.type == kARDSignalingMessageTypeAnswer) {
         strongSelf.hasReceivedSdp = YES;
         [strongSelf.messageQueue insertObject:message atIndex:0];
       } else {
         [strongSelf.messageQueue addObject:message];
       }
     }
     strongSelf.webSocketURL = response.webSocketURL;
     strongSelf.webSocketRestURL = response.webSocketRestURL;
     [strongSelf registerWithColliderIfReady];
     [strongSelf startSignalingIfReady];
   }];
 }

 - (void)disconnect {
   if (_state == kARDAppClientStateDisconnected) {
     return;
   }
   if (self.hasJoinedRoomServerRoom) {
     [_roomServerClient leaveRoomWithRoomId:_roomId
                                   clientId:_clientId
                          completionHandler:nil];
   }
   if (_channel) {
     if (_channel.state == kARDSignalingChannelStateRegistered) {
       // Tell the other client we're hanging up.
       ARDByeMessage *byeMessage = [[ARDByeMessage alloc] init];
       [_channel sendMessage:byeMessage];
     }
     // Disconnect from collider.
     _channel = nil;
   }
   _clientId = nil;
   _roomId = nil;
   _isInitiator = NO;
   _hasReceivedSdp = NO;
   _messageQueue = [NSMutableArray array];
   _peerConnection = nil;
   self.state = kARDAppClientStateDisconnected;
 }

 #pragma mark - ARDSignalingChannelDelegate

 - (void)channel:(id<ARDSignalingChannel>)channel
     didReceiveMessage:(ARDSignalingMessage *)message {
   switch (message.type) {
     case kARDSignalingMessageTypeOffer:
     case kARDSignalingMessageTypeAnswer:
       // Offers and answers must be processed before any other message, so we
       // place them at the front of the queue.
       _hasReceivedSdp = YES;
       [_messageQueue insertObject:message atIndex:0];
       break;
     case kARDSignalingMessageTypeCandidate:
       [_messageQueue addObject:message];
       break;
     case kARDSignalingMessageTypeBye:
       // Disconnects can be processed immediately.
       [self processSignalingMessage:message];
       return;
   }
   [self drainMessageQueueIfReady];
 }

 - (void)channel:(id<ARDSignalingChannel>)channel
     didChangeState:(ARDSignalingChannelState)state {
   switch (state) {
     case kARDSignalingChannelStateOpen:
       break;
     case kARDSignalingChannelStateRegistered:
       break;
     case kARDSignalingChannelStateClosed:
     case kARDSignalingChannelStateError:
       // TODO(tkchin): reconnection scenarios. Right now we just disconnect
       // completely if the websocket connection fails.
       [self disconnect];
       break;
   }
 }

 #pragma mark - RTCPeerConnectionDelegate
 // Callbacks for this delegate occur on non-main thread and need to be
 // dispatched back to main queue as needed.

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     signalingStateChanged:(RTCSignalingState)stateChanged {
   RTCLog(@"Signaling state changed: %d", stateChanged);
 }

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
            addedStream:(RTCMediaStream *)stream {
   dispatch_async(dispatch_get_main_queue(), ^{
     RTCLog(@"Received %lu video tracks and %lu audio tracks",
         (unsigned long)stream.videoTracks.count,
         (unsigned long)stream.audioTracks.count);
     if (stream.videoTracks.count) {
       RTCVideoTrack *videoTrack = stream.videoTracks[0];
       [_delegate appClient:self didReceiveRemoteVideoTrack:videoTrack];
     }
   });
 }

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
         removedStream:(RTCMediaStream *)stream {
   RTCLog(@"Stream was removed.");
 }

 - (void)peerConnectionOnRenegotiationNeeded:
     (RTCPeerConnection *)peerConnection {
   RTCLog(@"WARNING: Renegotiation needed but unimplemented.");
 }

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     iceConnectionChanged:(RTCICEConnectionState)newState {
   RTCLog(@"ICE state changed: %d", newState);
   dispatch_async(dispatch_get_main_queue(), ^{
     [_delegate appClient:self didChangeConnectionState:newState];
   });
 }

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     iceGatheringChanged:(RTCICEGatheringState)newState {
   RTCLog(@"ICE gathering state changed: %d", newState);
 }

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
        gotICECandidate:(RTCICECandidate *)candidate {
   dispatch_async(dispatch_get_main_queue(), ^{
     ARDICECandidateMessage *message =
         [[ARDICECandidateMessage alloc] initWithCandidate:candidate];
     [self sendSignalingMessage:message];
   });
 }

 - (void)peerConnection:(RTCPeerConnection*)peerConnection
     didOpenDataChannel:(RTCDataChannel*)dataChannel {
 }

 #pragma mark - RTCSessionDescriptionDelegate
 // Callbacks for this delegate occur on non-main thread and need to be
 // dispatched back to main queue as needed.

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     didCreateSessionDescription:(RTCSessionDescription *)sdp
                           error:(NSError *)error {
   dispatch_async(dispatch_get_main_queue(), ^{
     if (error) {
       RTCLogError(@"Failed to create session description. Error: %@", error);
       [self disconnect];
       NSDictionary *userInfo = @{
         NSLocalizedDescriptionKey: @"Failed to create session description.",
       };
       NSError *sdpError =
           [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                      code:kARDAppClientErrorCreateSDP
                                  userInfo:userInfo];
       [_delegate appClient:self didError:sdpError];
       return;
     }
     // Prefer H264 if available.
     RTCSessionDescription *sdpPreferringH264 =
         [ARDSDPUtils descriptionForDescription:sdp
                            preferredVideoCodec:@"H264"];
     [_peerConnection setLocalDescriptionWithDelegate:self
                                   sessionDescription:sdpPreferringH264];
     ARDSessionDescriptionMessage *message =
         [[ARDSessionDescriptionMessage alloc]
             initWithDescription:sdpPreferringH264];
     [self sendSignalingMessage:message];
   });
 }

 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     didSetSessionDescriptionWithError:(NSError *)error {
   dispatch_async(dispatch_get_main_queue(), ^{
     if (error) {
       RTCLogError(@"Failed to set session description. Error: %@", error);
       [self disconnect];
       NSDictionary *userInfo = @{
         NSLocalizedDescriptionKey: @"Failed to set session description.",
       };
       NSError *sdpError =
           [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                      code:kARDAppClientErrorSetSDP
                                  userInfo:userInfo];
       [_delegate appClient:self didError:sdpError];
       return;
     }
     // If we're answering and we've just set the remote offer we need to create
     // an answer and set the local description.
     if (!_isInitiator && !_peerConnection.localDescription) {
       RTCMediaConstraints *constraints = [self defaultAnswerConstraints];
       [_peerConnection createAnswerWithDelegate:self
                                     constraints:constraints];

     }
   });
 }

 #pragma mark - Private

 - (BOOL)hasJoinedRoomServerRoom {
   return _clientId.length;
 }

 // Begins the peer connection connection process if we have both joined a room
 // on the room server and tried to obtain a TURN server. Otherwise does nothing.
 // A peer connection object will be created with a stream that contains local
 // audio and video capture. If this client is the caller, an offer is created as
 // well, otherwise the client will wait for an offer to arrive.
 - (void)startSignalingIfReady {
   if (!_isTurnComplete || !self.hasJoinedRoomServerRoom) {
     return;
   }
   self.state = kARDAppClientStateConnected;

   // Create peer connection.
   RTCMediaConstraints *constraints = [self defaultPeerConnectionConstraints];
   RTCConfiguration *config = [[RTCConfiguration alloc] init];
   config.iceServers = _iceServers;
   _peerConnection = [_factory peerConnectionWithConfiguration:config
                                                   constraints:constraints
                                                      delegate:self];
   // Create AV media stream and add it to the peer connection.
   RTCMediaStream *localStream = [self createLocalMediaStream];
   [_peerConnection addStream:localStream];
   if (_isInitiator) {
     // Send offer.
     [_peerConnection createOfferWithDelegate:self
                                  constraints:[self defaultOfferConstraints]];
   } else {
     // Check if we've received an offer.
     [self drainMessageQueueIfReady];
   }
 }

 // Processes the messages that we've received from the room server and the
 // signaling channel. The offer or answer message must be processed before other
 // signaling messages, however they can arrive out of order. Hence, this method
 // only processes pending messages if there is a peer connection object and
 // if we have received either an offer or answer.
 - (void)drainMessageQueueIfReady {
   if (!_peerConnection || !_hasReceivedSdp) {
     return;
   }
   for (ARDSignalingMessage *message in _messageQueue) {
     [self processSignalingMessage:message];
   }
   [_messageQueue removeAllObjects];
 }

 // Processes the given signaling message based on its type.
 - (void)processSignalingMessage:(ARDSignalingMessage *)message {
   NSParameterAssert(_peerConnection ||
       message.type == kARDSignalingMessageTypeBye);
   switch (message.type) {
     case kARDSignalingMessageTypeOffer:
     case kARDSignalingMessageTypeAnswer: {
       ARDSessionDescriptionMessage *sdpMessage =
           (ARDSessionDescriptionMessage *)message;
       RTCSessionDescription *description = sdpMessage.sessionDescription;
       // Prefer H264 if available.
       RTCSessionDescription *sdpPreferringH264 =
           [ARDSDPUtils descriptionForDescription:description
                              preferredVideoCodec:@"H264"];
       [_peerConnection setRemoteDescriptionWithDelegate:self
                                      sessionDescription:sdpPreferringH264];
       break;
     }
     case kARDSignalingMessageTypeCandidate: {
       ARDICECandidateMessage *candidateMessage =
           (ARDICECandidateMessage *)message;
       [_peerConnection addICECandidate:candidateMessage.candidate];
       break;
     }
     case kARDSignalingMessageTypeBye:
       // Other client disconnected.
       // TODO(tkchin): support waiting in room for next client. For now just
       // disconnect.
       [self disconnect];
       break;
   }
 }

 // Sends a signaling message to the other client. The caller will send messages
 // through the room server, whereas the callee will send messages over the
 // signaling channel.
 - (void)sendSignalingMessage:(ARDSignalingMessage *)message {
   if (_isInitiator) {
     __weak ARDAppClient *weakSelf = self;
     [_roomServerClient sendMessage:message
                          forRoomId:_roomId
                           clientId:_clientId
                  completionHandler:^(ARDMessageResponse *response,
                                      NSError *error) {
       ARDAppClient *strongSelf = weakSelf;
       if (error) {
         [strongSelf.delegate appClient:strongSelf didError:error];
         return;
       }
       NSError *messageError =
           [[strongSelf class] errorForMessageResultType:response.result];
       if (messageError) {
         [strongSelf.delegate appClient:strongSelf didError:messageError];
         return;
       }
     }];
   } else {
     [_channel sendMessage:message];
   }
 }

 - (RTCMediaStream *)createLocalMediaStream {
   RTCMediaStream* localStream = [_factory mediaStreamWithLabel:@"ARDAMS"];
   RTCVideoTrack* localVideoTrack = [self createLocalVideoTrack];
   if (localVideoTrack) {
     [localStream addVideoTrack:localVideoTrack];
     [_delegate appClient:self didReceiveLocalVideoTrack:localVideoTrack];
   }
   [localStream addAudioTrack:[_factory audioTrackWithID:@"ARDAMSa0"]];
   return localStream;
 }

 - (RTCVideoTrack *)createLocalVideoTrack {
   RTCVideoTrack* localVideoTrack = nil;
   // The iOS simulator doesn't provide any sort of camera capture
   // support or emulation (http://goo.gl/rHAnC1) so don't bother
   // trying to open a local stream.
   // TODO(tkchin): local video capture for OSX. See
   // https://code.google.com/p/webrtc/issues/detail?id=3417.
 #if !TARGET_IPHONE_SIMULATOR && TARGET_OS_IPHONE
   RTCMediaConstraints *mediaConstraints = [self defaultMediaStreamConstraints];
   RTCAVFoundationVideoSource *source =
       [[RTCAVFoundationVideoSource alloc] initWithFactory:_factory
                                               constraints:mediaConstraints];
   localVideoTrack =
       [[RTCVideoTrack alloc] initWithFactory:_factory
                                       source:source
                                      trackId:@"ARDAMSv0"];
 #endif
   return localVideoTrack;
 }

 #pragma mark - Collider methods

 - (void)registerWithColliderIfReady {
   if (!self.hasJoinedRoomServerRoom) {
     return;
   }
   // Open WebSocket connection.
   if (!_channel) {
     _channel =
         [[ARDWebSocketChannel alloc] initWithURL:_websocketURL
                                          restURL:_websocketRestURL
                                         delegate:self];
   }
   [_channel registerForRoomId:_roomId clientId:_clientId];
 }

 #pragma mark - Defaults

 - (RTCMediaConstraints *)defaultMediaStreamConstraints {
   RTCMediaConstraints* constraints =
       [[RTCMediaConstraints alloc]
           initWithMandatoryConstraints:nil
                    optionalConstraints:nil];
   return constraints;
 }

 - (RTCMediaConstraints *)defaultAnswerConstraints {
   return [self defaultOfferConstraints];
 }

 - (RTCMediaConstraints *)defaultOfferConstraints {
   NSArray *mandatoryConstraints = @[
       [[RTCPair alloc] initWithKey:@"OfferToReceiveAudio" value:@"true"],
       [[RTCPair alloc] initWithKey:@"OfferToReceiveVideo" value:@"true"]
   ];
   RTCMediaConstraints* constraints =
       [[RTCMediaConstraints alloc]
           initWithMandatoryConstraints:mandatoryConstraints
                    optionalConstraints:nil];
   return constraints;
 }

 - (RTCMediaConstraints *)defaultPeerConnectionConstraints {
   if (_defaultPeerConnectionConstraints) {
     return _defaultPeerConnectionConstraints;
   }
   NSArray *optionalConstraints = @[
       [[RTCPair alloc] initWithKey:@"DtlsSrtpKeyAgreement" value:@"true"]
   ];
   RTCMediaConstraints* constraints =
       [[RTCMediaConstraints alloc]
           initWithMandatoryConstraints:nil
                    optionalConstraints:optionalConstraints];
   return constraints;
 }

 - (RTCICEServer *)defaultSTUNServer {
   NSURL *defaultSTUNServerURL = [NSURL URLWithString:kARDDefaultSTUNServerUrl];
   return [[RTCICEServer alloc] initWithURI:defaultSTUNServerURL
                                   username:@""
                                   password:@""];
 }

 #pragma mark - Errors

 + (NSError *)errorForJoinResultType:(ARDJoinResultType)resultType {
   NSError *error = nil;
   switch (resultType) {
     case kARDJoinResultTypeSuccess:
       break;
     case kARDJoinResultTypeUnknown: {
       error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                          code:kARDAppClientErrorUnknown
                                      userInfo:@{
         NSLocalizedDescriptionKey: @"Unknown error.",
       }];
       break;
     }
     case kARDJoinResultTypeFull: {
       error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                          code:kARDAppClientErrorRoomFull
                                      userInfo:@{
         NSLocalizedDescriptionKey: @"Room is full.",
       }];
       break;
     }
   }
   return error;
 }

 + (NSError *)errorForMessageResultType:(ARDMessageResultType)resultType {
   NSError *error = nil;
   switch (resultType) {
     case kARDMessageResultTypeSuccess:
       break;
     case kARDMessageResultTypeUnknown:
       error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                          code:kARDAppClientErrorUnknown
                                      userInfo:@{
         NSLocalizedDescriptionKey: @"Unknown error.",
       }];
       break;
     case kARDMessageResultTypeInvalidClient:
       error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                          code:kARDAppClientErrorInvalidClient
                                      userInfo:@{
         NSLocalizedDescriptionKey: @"Invalid client.",
       }];
       break;
     case kARDMessageResultTypeInvalidRoom:
       error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
                                          code:kARDAppClientErrorInvalidRoom
                                      userInfo:@{
         NSLocalizedDescriptionKey: @"Invalid room.",
       }];
       break;
   }
   return error;
 }

 @end
	/*
	* Copyright 2014 The WebRTC Project Authors. All rights reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	#import "ARDAppClient+Internal.h"

	#if defined(WEBRTC_IOS)
	#import "RTCAVFoundationVideoSource.h"
	#endif
	#import "RTCFileLogger.h"
	#import "RTCICEServer.h"
	#import "RTCLogging.h"
	#import "RTCMediaConstraints.h"
	#import "RTCMediaStream.h"
	#import "RTCPair.h"
	#import "RTCPeerConnectionInterface.h"
	#import "RTCVideoCapturer.h"

	#import "ARDAppEngineClient.h"
	#import "ARDCEODTURNClient.h"
	#import "ARDJoinResponse.h"
	#import "ARDMessageResponse.h"
	#import "ARDSDPUtils.h"
	#import "ARDSignalingMessage.h"
	#import "ARDUtilities.h"
	#import "ARDWebSocketChannel.h"
	#import "RTCICECandidate+JSON.h"
	#import "RTCSessionDescription+JSON.h"


	static NSString * const kARDDefaultSTUNServerUrl =
	@"stun:stun.l.google.com:19302";
	// TODO(tkchin): figure out a better username for CEOD statistics.
	static NSString * const kARDTurnRequestUrl =
	@"https://computeengineondemand.appspot.com"
	@"/turn?username=iapprtc&key=4080218913";

	static NSString * const kARDAppClientErrorDomain = @"ARDAppClient";
	static NSInteger const kARDAppClientErrorUnknown = -1;
	static NSInteger const kARDAppClientErrorRoomFull = -2;
	static NSInteger const kARDAppClientErrorCreateSDP = -3;
	static NSInteger const kARDAppClientErrorSetSDP = -4;
	static NSInteger const kARDAppClientErrorInvalidClient = -5;
	static NSInteger const kARDAppClientErrorInvalidRoom = -6;

	@implementation ARDAppClient {
	RTCFileLogger *_fileLogger;
	}

	@synthesize delegate = _delegate;
	@synthesize state = _state;
	@synthesize roomServerClient = _roomServerClient;
	@synthesize channel = _channel;
	@synthesize turnClient = _turnClient;
	@synthesize peerConnection = _peerConnection;
	@synthesize factory = _factory;
	@synthesize messageQueue = _messageQueue;
	@synthesize isTurnComplete = _isTurnComplete;
	@synthesize hasReceivedSdp = _hasReceivedSdp;
	@synthesize roomId = _roomId;
	@synthesize clientId = _clientId;
	@synthesize isInitiator = _isInitiator;
	@synthesize iceServers = _iceServers;
	@synthesize webSocketURL = _websocketURL;
	@synthesize webSocketRestURL = _websocketRestURL;
	@synthesize defaultPeerConnectionConstraints =
	_defaultPeerConnectionConstraints;

	- (instancetype)init {
	if (self = [super init]) {
	_roomServerClient = [[ARDAppEngineClient alloc] init];
	NSURL *turnRequestURL = [NSURL URLWithString:kARDTurnRequestUrl];
	_turnClient = [[ARDCEODTURNClient alloc] initWithURL:turnRequestURL];
	[self configure];
	}
	return self;
	}

	- (instancetype)initWithDelegate:(id<ARDAppClientDelegate>)delegate {
	if (self = [super init]) {
	_roomServerClient = [[ARDAppEngineClient alloc] init];
	_delegate = delegate;
	NSURL *turnRequestURL = [NSURL URLWithString:kARDTurnRequestUrl];
	_turnClient = [[ARDCEODTURNClient alloc] initWithURL:turnRequestURL];
	[self configure];
	}
	return self;
	}

	// TODO(tkchin): Provide signaling channel factory interface so we can recreate
	// channel if we need to on network failure. Also, make this the default public
	// constructor.
	- (instancetype)initWithRoomServerClient:(id<ARDRoomServerClient>)rsClient
	signalingChannel:(id<ARDSignalingChannel>)channel
	turnClient:(id<ARDTURNClient>)turnClient
	delegate:(id<ARDAppClientDelegate>)delegate {
	NSParameterAssert(rsClient);
	NSParameterAssert(channel);
	NSParameterAssert(turnClient);
	if (self = [super init]) {
	_roomServerClient = rsClient;
	_channel = channel;
	_turnClient = turnClient;
	_delegate = delegate;
	[self configure];
	}
	return self;
	}

	- (void)configure {
	_factory = [[RTCPeerConnectionFactory alloc] init];
	_messageQueue = [NSMutableArray array];
	_iceServers = [NSMutableArray arrayWithObject:[self defaultSTUNServer]];
	_fileLogger = [[RTCFileLogger alloc] init];
	[_fileLogger start];
	}

	- (void)dealloc {
	[self disconnect];
	}

	- (void)setState:(ARDAppClientState)state {
	if (_state == state) {
	return;
	}
	_state = state;
	[_delegate appClient:self didChangeState:_state];
	}

	- (void)connectToRoomWithId:(NSString *)roomId
	options:(NSDictionary *)options {
	NSParameterAssert(roomId.length);
	NSParameterAssert(_state == kARDAppClientStateDisconnected);
	self.state = kARDAppClientStateConnecting;

	// Request TURN.
	__weak ARDAppClient *weakSelf = self;
	[_turnClient requestServersWithCompletionHandler:^(NSArray *turnServers,
	NSError *error) {
	if (error) {
	RTCLogError("Error retrieving TURN servers: %@",
	error.localizedDescription);
	}
	ARDAppClient *strongSelf = weakSelf;
	[strongSelf.iceServers addObjectsFromArray:turnServers];
	strongSelf.isTurnComplete = YES;
	[strongSelf startSignalingIfReady];
	}];

	// Join room on room server.
	[_roomServerClient joinRoomWithRoomId:roomId
	completionHandler:^(ARDJoinResponse response, NSError error) {
	ARDAppClient *strongSelf = weakSelf;
	if (error) {
	[strongSelf.delegate appClient:strongSelf didError:error];
	return;
	}
	NSError *joinError =
	[[strongSelf class] errorForJoinResultType:response.result];
	if (joinError) {
	RTCLogError(@"Failed to join room:%@ on room server.", roomId);
	[strongSelf disconnect];
	[strongSelf.delegate appClient:strongSelf didError:joinError];
	return;
	}
	RTCLog(@"Joined room:%@ on room server.", roomId);
	strongSelf.roomId = response.roomId;
	strongSelf.clientId = response.clientId;
	strongSelf.isInitiator = response.isInitiator;
	for (ARDSignalingMessage *message in response.messages) {
	if (message.type == kARDSignalingMessageTypeOffer \|\|
	message.type == kARDSignalingMessageTypeAnswer) {
	strongSelf.hasReceivedSdp = YES;
	[strongSelf.messageQueue insertObject:message atIndex:0];
	} else {
	[strongSelf.messageQueue addObject:message];
	}
	}
	strongSelf.webSocketURL = response.webSocketURL;
	strongSelf.webSocketRestURL = response.webSocketRestURL;
	[strongSelf registerWithColliderIfReady];
	[strongSelf startSignalingIfReady];
	}];
	}

	- (void)disconnect {
	if (_state == kARDAppClientStateDisconnected) {
	return;
	}
	if (self.hasJoinedRoomServerRoom) {
	[_roomServerClient leaveRoomWithRoomId:_roomId
	clientId:_clientId
	completionHandler:nil];
	}
	if (_channel) {
	if (_channel.state == kARDSignalingChannelStateRegistered) {
	// Tell the other client we're hanging up.
	ARDByeMessage *byeMessage = [[ARDByeMessage alloc] init];
	[_channel sendMessage:byeMessage];
	}
	// Disconnect from collider.
	_channel = nil;
	}
	_clientId = nil;
	_roomId = nil;
	_isInitiator = NO;
	_hasReceivedSdp = NO;
	_messageQueue = [NSMutableArray array];
	_peerConnection = nil;
	self.state = kARDAppClientStateDisconnected;
	}

	#pragma mark - ARDSignalingChannelDelegate

	- (void)channel:(id<ARDSignalingChannel>)channel
	didReceiveMessage:(ARDSignalingMessage *)message {
	switch (message.type) {
	case kARDSignalingMessageTypeOffer:
	case kARDSignalingMessageTypeAnswer:
	// Offers and answers must be processed before any other message, so we
	// place them at the front of the queue.
	_hasReceivedSdp = YES;
	[_messageQueue insertObject:message atIndex:0];
	break;
	case kARDSignalingMessageTypeCandidate:
	[_messageQueue addObject:message];
	break;
	case kARDSignalingMessageTypeBye:
	// Disconnects can be processed immediately.
	[self processSignalingMessage:message];
	return;
	}
	[self drainMessageQueueIfReady];
	}

	- (void)channel:(id<ARDSignalingChannel>)channel
	didChangeState:(ARDSignalingChannelState)state {
	switch (state) {
	case kARDSignalingChannelStateOpen:
	break;
	case kARDSignalingChannelStateRegistered:
	break;
	case kARDSignalingChannelStateClosed:
	case kARDSignalingChannelStateError:
	// TODO(tkchin): reconnection scenarios. Right now we just disconnect
	// completely if the websocket connection fails.
	[self disconnect];
	break;
	}
	}

	#pragma mark - RTCPeerConnectionDelegate
	// Callbacks for this delegate occur on non-main thread and need to be
	// dispatched back to main queue as needed.

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	signalingStateChanged:(RTCSignalingState)stateChanged {
	RTCLog(@"Signaling state changed: %d", stateChanged);
	}

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	addedStream:(RTCMediaStream *)stream {
	dispatch_async(dispatch_get_main_queue(), ^{
	RTCLog(@"Received %lu video tracks and %lu audio tracks",
	(unsigned long)stream.videoTracks.count,
	(unsigned long)stream.audioTracks.count);
	if (stream.videoTracks.count) {
	RTCVideoTrack *videoTrack = stream.videoTracks[0];
	[_delegate appClient:self didReceiveRemoteVideoTrack:videoTrack];
	}
	});
	}

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	removedStream:(RTCMediaStream *)stream {
	RTCLog(@"Stream was removed.");
	}

	- (void)peerConnectionOnRenegotiationNeeded:
	(RTCPeerConnection *)peerConnection {
	RTCLog(@"WARNING: Renegotiation needed but unimplemented.");
	}

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	iceConnectionChanged:(RTCICEConnectionState)newState {
	RTCLog(@"ICE state changed: %d", newState);
	dispatch_async(dispatch_get_main_queue(), ^{
	[_delegate appClient:self didChangeConnectionState:newState];
	});
	}

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	iceGatheringChanged:(RTCICEGatheringState)newState {
	RTCLog(@"ICE gathering state changed: %d", newState);
	}

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	gotICECandidate:(RTCICECandidate *)candidate {
	dispatch_async(dispatch_get_main_queue(), ^{
	ARDICECandidateMessage *message =
	[[ARDICECandidateMessage alloc] initWithCandidate:candidate];
	[self sendSignalingMessage:message];
	});
	}

	- (void)peerConnection:(RTCPeerConnection*)peerConnection
	didOpenDataChannel:(RTCDataChannel*)dataChannel {
	}

	#pragma mark - RTCSessionDescriptionDelegate
	// Callbacks for this delegate occur on non-main thread and need to be
	// dispatched back to main queue as needed.

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	didCreateSessionDescription:(RTCSessionDescription *)sdp
	error:(NSError *)error {
	dispatch_async(dispatch_get_main_queue(), ^{
	if (error) {
	RTCLogError(@"Failed to create session description. Error: %@", error);
	[self disconnect];
	NSDictionary *userInfo = @{
	NSLocalizedDescriptionKey: @"Failed to create session description.",
	};
	NSError *sdpError =
	[[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorCreateSDP
	userInfo:userInfo];
	[_delegate appClient:self didError:sdpError];
	return;
	}
	// Prefer H264 if available.
	RTCSessionDescription *sdpPreferringH264 =
	[ARDSDPUtils descriptionForDescription:sdp
	preferredVideoCodec:@"H264"];
	[_peerConnection setLocalDescriptionWithDelegate:self
	sessionDescription:sdpPreferringH264];
	ARDSessionDescriptionMessage *message =
	[[ARDSessionDescriptionMessage alloc]
	initWithDescription:sdpPreferringH264];
	[self sendSignalingMessage:message];
	});
	}

	- (void)peerConnection:(RTCPeerConnection *)peerConnection
	didSetSessionDescriptionWithError:(NSError *)error {
	dispatch_async(dispatch_get_main_queue(), ^{
	if (error) {
	RTCLogError(@"Failed to set session description. Error: %@", error);
	[self disconnect];
	NSDictionary *userInfo = @{
	NSLocalizedDescriptionKey: @"Failed to set session description.",
	};
	NSError *sdpError =
	[[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorSetSDP
	userInfo:userInfo];
	[_delegate appClient:self didError:sdpError];
	return;
	}
	// If we're answering and we've just set the remote offer we need to create
	// an answer and set the local description.
	if (!_isInitiator && !_peerConnection.localDescription) {
	RTCMediaConstraints *constraints = [self defaultAnswerConstraints];
	[_peerConnection createAnswerWithDelegate:self
	constraints:constraints];

	}
	});
	}

	#pragma mark - Private

	- (BOOL)hasJoinedRoomServerRoom {
	return _clientId.length;
	}

	// Begins the peer connection connection process if we have both joined a room
	// on the room server and tried to obtain a TURN server. Otherwise does nothing.
	// A peer connection object will be created with a stream that contains local
	// audio and video capture. If this client is the caller, an offer is created as
	// well, otherwise the client will wait for an offer to arrive.
	- (void)startSignalingIfReady {
	if (!_isTurnComplete \|\| !self.hasJoinedRoomServerRoom) {
	return;
	}
	self.state = kARDAppClientStateConnected;

	// Create peer connection.
	RTCMediaConstraints *constraints = [self defaultPeerConnectionConstraints];
	RTCConfiguration *config = [[RTCConfiguration alloc] init];
	config.iceServers = _iceServers;
	_peerConnection = [_factory peerConnectionWithConfiguration:config
	constraints:constraints
	delegate:self];
	// Create AV media stream and add it to the peer connection.
	RTCMediaStream *localStream = [self createLocalMediaStream];
	[_peerConnection addStream:localStream];
	if (_isInitiator) {
	// Send offer.
	[_peerConnection createOfferWithDelegate:self
	constraints:[self defaultOfferConstraints]];
	} else {
	// Check if we've received an offer.
	[self drainMessageQueueIfReady];
	}
	}

	// Processes the messages that we've received from the room server and the
	// signaling channel. The offer or answer message must be processed before other
	// signaling messages, however they can arrive out of order. Hence, this method
	// only processes pending messages if there is a peer connection object and
	// if we have received either an offer or answer.
	- (void)drainMessageQueueIfReady {
	if (!_peerConnection \|\| !_hasReceivedSdp) {
	return;
	}
	for (ARDSignalingMessage *message in _messageQueue) {
	[self processSignalingMessage:message];
	}
	[_messageQueue removeAllObjects];
	}

	// Processes the given signaling message based on its type.
	- (void)processSignalingMessage:(ARDSignalingMessage *)message {
	NSParameterAssert(_peerConnection \|\|
	message.type == kARDSignalingMessageTypeBye);
	switch (message.type) {
	case kARDSignalingMessageTypeOffer:
	case kARDSignalingMessageTypeAnswer: {
	ARDSessionDescriptionMessage *sdpMessage =
	(ARDSessionDescriptionMessage *)message;
	RTCSessionDescription *description = sdpMessage.sessionDescription;
	// Prefer H264 if available.
	RTCSessionDescription *sdpPreferringH264 =
	[ARDSDPUtils descriptionForDescription:description
	preferredVideoCodec:@"H264"];
	[_peerConnection setRemoteDescriptionWithDelegate:self
	sessionDescription:sdpPreferringH264];
	break;
	}
	case kARDSignalingMessageTypeCandidate: {
	ARDICECandidateMessage *candidateMessage =
	(ARDICECandidateMessage *)message;
	[_peerConnection addICECandidate:candidateMessage.candidate];
	break;
	}
	case kARDSignalingMessageTypeBye:
	// Other client disconnected.
	// TODO(tkchin): support waiting in room for next client. For now just
	// disconnect.
	[self disconnect];
	break;
	}
	}

	// Sends a signaling message to the other client. The caller will send messages
	// through the room server, whereas the callee will send messages over the
	// signaling channel.
	- (void)sendSignalingMessage:(ARDSignalingMessage *)message {
	if (_isInitiator) {
	__weak ARDAppClient *weakSelf = self;
	[_roomServerClient sendMessage:message
	forRoomId:_roomId
	clientId:_clientId
	completionHandler:^(ARDMessageResponse *response,
	NSError *error) {
	ARDAppClient *strongSelf = weakSelf;
	if (error) {
	[strongSelf.delegate appClient:strongSelf didError:error];
	return;
	}
	NSError *messageError =
	[[strongSelf class] errorForMessageResultType:response.result];
	if (messageError) {
	[strongSelf.delegate appClient:strongSelf didError:messageError];
	return;
	}
	}];
	} else {
	[_channel sendMessage:message];
	}
	}

	- (RTCMediaStream *)createLocalMediaStream {
	RTCMediaStream* localStream = [_factory mediaStreamWithLabel:@"ARDAMS"];
	RTCVideoTrack* localVideoTrack = [self createLocalVideoTrack];
	if (localVideoTrack) {
	[localStream addVideoTrack:localVideoTrack];
	[_delegate appClient:self didReceiveLocalVideoTrack:localVideoTrack];
	}
	[localStream addAudioTrack:[_factory audioTrackWithID:@"ARDAMSa0"]];
	return localStream;
	}

	- (RTCVideoTrack *)createLocalVideoTrack {
	RTCVideoTrack* localVideoTrack = nil;
	// The iOS simulator doesn't provide any sort of camera capture
	// support or emulation (http://goo.gl/rHAnC1) so don't bother
	// trying to open a local stream.
	// TODO(tkchin): local video capture for OSX. See
	// https://code.google.com/p/webrtc/issues/detail?id=3417.
	#if !TARGET_IPHONE_SIMULATOR && TARGET_OS_IPHONE
	RTCMediaConstraints *mediaConstraints = [self defaultMediaStreamConstraints];
	RTCAVFoundationVideoSource *source =
	[[RTCAVFoundationVideoSource alloc] initWithFactory:_factory
	constraints:mediaConstraints];
	localVideoTrack =
	[[RTCVideoTrack alloc] initWithFactory:_factory
	source:source
	trackId:@"ARDAMSv0"];
	#endif
	return localVideoTrack;
	}

	#pragma mark - Collider methods

	- (void)registerWithColliderIfReady {
	if (!self.hasJoinedRoomServerRoom) {
	return;
	}
	// Open WebSocket connection.
	if (!_channel) {
	_channel =
	[[ARDWebSocketChannel alloc] initWithURL:_websocketURL
	restURL:_websocketRestURL
	delegate:self];
	}
	[_channel registerForRoomId:_roomId clientId:_clientId];
	}

	#pragma mark - Defaults

	- (RTCMediaConstraints *)defaultMediaStreamConstraints {
	RTCMediaConstraints* constraints =
	[[RTCMediaConstraints alloc]
	initWithMandatoryConstraints:nil
	optionalConstraints:nil];
	return constraints;
	}

	- (RTCMediaConstraints *)defaultAnswerConstraints {
	return [self defaultOfferConstraints];
	}

	- (RTCMediaConstraints *)defaultOfferConstraints {
	NSArray *mandatoryConstraints = @[
	[[RTCPair alloc] initWithKey:@"OfferToReceiveAudio" value:@"true"],
	[[RTCPair alloc] initWithKey:@"OfferToReceiveVideo" value:@"true"]
	];
	RTCMediaConstraints* constraints =
	[[RTCMediaConstraints alloc]
	initWithMandatoryConstraints:mandatoryConstraints
	optionalConstraints:nil];
	return constraints;
	}

	- (RTCMediaConstraints *)defaultPeerConnectionConstraints {
	if (_defaultPeerConnectionConstraints) {
	return _defaultPeerConnectionConstraints;
	}
	NSArray *optionalConstraints = @[
	[[RTCPair alloc] initWithKey:@"DtlsSrtpKeyAgreement" value:@"true"]
	];
	RTCMediaConstraints* constraints =
	[[RTCMediaConstraints alloc]
	initWithMandatoryConstraints:nil
	optionalConstraints:optionalConstraints];
	return constraints;
	}

	- (RTCICEServer *)defaultSTUNServer {
	NSURL *defaultSTUNServerURL = [NSURL URLWithString:kARDDefaultSTUNServerUrl];
	return [[RTCICEServer alloc] initWithURI:defaultSTUNServerURL
	username:@""
	password:@""];
	}

	#pragma mark - Errors

	+ (NSError *)errorForJoinResultType:(ARDJoinResultType)resultType {
	NSError *error = nil;
	switch (resultType) {
	case kARDJoinResultTypeSuccess:
	break;
	case kARDJoinResultTypeUnknown: {
	error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorUnknown
	userInfo:@{
	NSLocalizedDescriptionKey: @"Unknown error.",
	}];
	break;
	}
	case kARDJoinResultTypeFull: {
	error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorRoomFull
	userInfo:@{
	NSLocalizedDescriptionKey: @"Room is full.",
	}];
	break;
	}
	}
	return error;
	}

	+ (NSError *)errorForMessageResultType:(ARDMessageResultType)resultType {
	NSError *error = nil;
	switch (resultType) {
	case kARDMessageResultTypeSuccess:
	break;
	case kARDMessageResultTypeUnknown:
	error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorUnknown
	userInfo:@{
	NSLocalizedDescriptionKey: @"Unknown error.",
	}];
	break;
	case kARDMessageResultTypeInvalidClient:
	error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorInvalidClient
	userInfo:@{
	NSLocalizedDescriptionKey: @"Invalid client.",
	}];
	break;
	case kARDMessageResultTypeInvalidRoom:
	error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
	code:kARDAppClientErrorInvalidRoom
	userInfo:@{
	NSLocalizedDescriptionKey: @"Invalid room.",
	}];
	break;
	}
	return error;
	}

	@end