SDLProtocol.m

//  SDLProtocol.m
//


#import "SDLFunctionID.h"

#import "SDLTransportType.h"
#import "SDLControlFramePayloadConstants.h"
#import "SDLControlFramePayloadEndService.h"
#import "SDLControlFramePayloadNak.h"
#import "SDLControlFramePayloadRegisterSecondaryTransportNak.h"
#import "SDLControlFramePayloadRPCStartService.h"
#import "SDLControlFramePayloadRPCStartServiceAck.h"
#import "SDLEncryptionLifecycleManager.h"
#import "SDLLogMacros.h"
#import "SDLGlobals.h"
#import "SDLPrioritizedObjectCollection.h"
#import "SDLProtocol.h"
#import "SDLProtocolHeader.h"
#import "SDLProtocolMessage.h"
#import "SDLProtocolMessageDisassembler.h"
#import "SDLProtocolReceivedMessageRouter.h"
#import "SDLRPCNotification.h"
#import "SDLRPCPayload.h"
#import "SDLRPCRequest.h"
#import "SDLRPCResponse.h"
#import "SDLSecurityType.h"
#import "SDLTimer.h"
#import "SDLVersion.h"
#import "SDLV2ProtocolHeader.h"

NSString *const SDLProtocolSecurityErrorDomain = @"com.sdl.protocol.security";


#pragma mark - SDLProtocol Private Interface

typedef NSNumber SDLServiceTypeBox;

NS_ASSUME_NONNULL_BEGIN

@interface SDLProtocol () {
    UInt32 _messageID;
    SDLPrioritizedObjectCollection *_prioritizedCollection;
}

@property (strong, nonatomic) NSMutableData *receiveBuffer;
@property (nullable, strong, nonatomic) SDLProtocolReceivedMessageRouter *messageRouter;
@property (strong, nonatomic) NSMutableDictionary<SDLServiceTypeBox *, SDLProtocolHeader *> *serviceHeaders;
@property (assign, nonatomic) int32_t hashId;

// Readonly public properties
@property (strong, nonatomic, readwrite, nullable) NSString *authToken;

@end


#pragma mark - SDLProtocol Implementation

@implementation SDLProtocol

#pragma mark - Lifecycle

- (instancetype)initWithTransport:(id<SDLTransportType>)transport encryptionManager:(nullable SDLEncryptionLifecycleManager *)encryptionManager {
    self = [super init];
    if (!self) { return nil; }

    SDLLogV(@"Initializing protocol with transport: %@, encryption manager: %@", transport, encryptionManager);
    _messageID = 0;
    _hashId = SDLControlFrameInt32NotFound;
    _prioritizedCollection = [[SDLPrioritizedObjectCollection alloc] init];
    _protocolDelegateTable = [NSHashTable weakObjectsHashTable];
    _serviceHeaders = [[NSMutableDictionary alloc] init];
    _messageRouter = [[SDLProtocolReceivedMessageRouter alloc] init];
    _messageRouter.delegate = self;

    _transport = transport;
    _transport.delegate = self;

    _encryptionLifecycleManager = encryptionManager;
    
    return self;
}

- (void)start {
    SDLLogD(@"Starting protocol: %@", self);
    [self.transport connect];
}

- (void)stopWithCompletionHandler:(void (^)(void))disconnectCompletionHandler {
    SDLLogD(@"Stopping protocol: %@, disconnecting transport and stopping security manager", self);
    [self.securityManager stop];
    [self.transport disconnectWithCompletionHandler:^{
        disconnectCompletionHandler();
    }];
}

#pragma mark - Service metadata
- (BOOL)storeHeader:(SDLProtocolHeader *)header forServiceType:(SDLServiceType)serviceType {
    if (header == nil) {
        return NO;
    }

    SDLLogD(@"Storing SessionID %i of serviceType %i", header.sessionID, serviceType);
    self.serviceHeaders[@(serviceType)] = [header copy];
    return YES;
}

- (UInt8)sdl_retrieveSessionIDforServiceType:(SDLServiceType)serviceType {
    SDLProtocolHeader *header = self.serviceHeaders[@(serviceType)];
    if (header == nil) {
        // The first time the RPC service type is created, there's no header, so we don't need to warn.
        if (serviceType != SDLServiceTypeRPC) {
            SDLLogW(@"Warning: Tried to retrieve sessionID for serviceType %i, but no header is saved for that service type.", serviceType);
        }

        return 0;
    }

    return header.sessionID;
}

#pragma mark - SDLTransportDelegate

- (void)onTransportConnected {
    SDLLogV(@"Transport connected, opening protocol");
    NSArray<id<SDLProtocolDelegate>> *listeners;
    @synchronized(self.protocolDelegateTable) {
        listeners = self.protocolDelegateTable.allObjects;
    }
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocolDidOpen:)]) {
            [listener protocolDidOpen:self];
        }
    }
}

- (void)onTransportDisconnected {
    SDLLogV(@"Transport disconnected, closing protocol");
    NSArray<id<SDLProtocolDelegate>> *listeners;
    @synchronized(self.protocolDelegateTable) {
        listeners = self.protocolDelegateTable.allObjects;
    }
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocolDidClose:)]) {
            [listener protocolDidClose:self];
        }
    }
}

- (void)onDataReceived:(NSData *)receivedData {
    [self sdl_handleBytesFromTransport:receivedData];
}

- (void)onError:(NSError *)error {
    SDLLogV(@"Transport received an error: %@", error);
    for (id<SDLProtocolDelegate> listener in self.protocolDelegateTable.allObjects) {
        if ([listener respondsToSelector:@selector(protocol:transportDidError:)]) {
            [listener protocol:self transportDidError:error];
        }
    }
}

#pragma mark - Start Service

- (void)startServiceWithType:(SDLServiceType)serviceType payload:(nullable NSData *)payload {
    // No encryption, just build and send the message synchronously
    SDLProtocolMessage *message = [self sdl_createStartServiceMessageWithType:serviceType encrypted:NO payload:payload];
    SDLLogD(@"Sending start service: %@", message);
    [self sdl_sendDataToTransport:message.data onService:serviceType];
}

- (void)startSecureServiceWithType:(SDLServiceType)serviceType payload:(nullable NSData *)payload tlsInitializationHandler:(void (^)(BOOL success, NSError *error))tlsInitializationHandler {
    SDLLogD(@"Attempting to start TLS for service type: %hhu", serviceType);
    [self sdl_initializeTLSEncryptionWithCompletionHandler:^(BOOL success, NSError *error) {
        if (!success) {
            // We can't start the service because we don't have encryption, return the error
            tlsInitializationHandler(success, error);
            BLOCK_RETURN;
        }

        // TLS initialization succeeded. Build and send the message.
        SDLProtocolMessage *message = [self sdl_createStartServiceMessageWithType:serviceType encrypted:YES payload:nil];
        SDLLogD(@"TLS initialized, sending start service for message: %@", message);
        [self sdl_sendDataToTransport:message.data onService:serviceType];
    }];
}

- (SDLProtocolMessage *)sdl_createStartServiceMessageWithType:(SDLServiceType)serviceType encrypted:(BOOL)encryption payload:(nullable NSData *)payload {
    SDLProtocolHeader *header = [SDLProtocolHeader headerForVersion:(UInt8)[SDLGlobals sharedGlobals].protocolVersion.major];
    NSData *servicePayload = payload;

    header.sessionID = [self sdl_retrieveSessionIDforServiceType:SDLServiceTypeRPC];
    header.frameType = SDLFrameTypeControl;
    header.serviceType = serviceType;
    header.frameData = SDLFrameInfoStartService;

    // Sending a StartSession with the encrypted bit set causes module to initiate SSL Handshake with a ClientHello message, which should be handled by the 'processControlService' method.
    header.encrypted = encryption;

    return [SDLProtocolMessage messageWithHeader:header andPayload:servicePayload];
}

- (void)sdl_initializeTLSEncryptionWithCompletionHandler:(void (^)(BOOL success, NSError *_Nullable error))completionHandler {
    if (self.securityManager == nil) {
        SDLLogE(@"Could not start streaming service, encryption was requested by the remote system but failed because there is no security manager set for this app.");

        if (completionHandler != nil) {
            completionHandler(NO, [NSError errorWithDomain:SDLProtocolSecurityErrorDomain code:SDLProtocolErrorNoSecurityManager userInfo:nil]);
        }

        return;
    }

    SDLLogD(@"Telling security manager to initialize");
    [self.securityManager initializeWithAppId:self.appId completionHandler:^(NSError *_Nullable error) {
        if (error) {
            SDLLogE(@"Security Manager failed to initialize with error: %@", error);

            if (completionHandler != nil) {
                completionHandler(NO, error);
            }
        } else {
            if (completionHandler != nil) {
                completionHandler(YES, nil);
            }
        }
    }];
}


#pragma mark - End Service

- (void)endServiceWithType:(SDLServiceType)serviceType {
    SDLProtocolHeader *header = [SDLProtocolHeader headerForVersion:(UInt8)[SDLGlobals sharedGlobals].protocolVersion.major];
    header.frameType = SDLFrameTypeControl;
    header.serviceType = serviceType;
    header.frameData = SDLFrameInfoEndService;
    header.sessionID = [self sdl_retrieveSessionIDforServiceType:serviceType];

    // Assemble the payload, it's a full control frame if we're on 5.0+, it's just the hash id if we are not
    NSData *payload = nil;
    if (self.hashId != SDLControlFrameInt32NotFound) {
        if([SDLGlobals sharedGlobals].protocolVersion.major > 4) {
            SDLControlFramePayloadEndService *endServicePayload = [[SDLControlFramePayloadEndService alloc] initWithHashId:self.hashId];
            payload = endServicePayload.data;
        } else {
            payload = [NSData dataWithBytes:&_hashId length:sizeof(_hashId)];
        }
    }

    SDLProtocolMessage *message = [SDLProtocolMessage messageWithHeader:header andPayload:payload];
    SDLLogD(@"Sending end service: %@", message);
    [self sdl_sendDataToTransport:message.data onService:serviceType];
}


#pragma mark - Register Secondary Transport

- (void)registerSecondaryTransport {
    SDLLogV(@"Attempting to register the secondary transport");

    SDLProtocolHeader *header = [SDLProtocolHeader headerForVersion:(UInt8)[SDLGlobals sharedGlobals].protocolVersion.major];
    header.frameType = SDLFrameTypeControl;
    header.serviceType = SDLServiceTypeControl;
    header.frameData = SDLFrameInfoRegisterSecondaryTransport;
    header.sessionID = [self sdl_retrieveSessionIDforServiceType:SDLServiceTypeControl];
    if ([SDLGlobals sharedGlobals].protocolVersion.major >= 2) {
        [((SDLV2ProtocolHeader *)header) setMessageID:++_messageID];
    }

    SDLProtocolMessage *message = [SDLProtocolMessage messageWithHeader:header andPayload:nil];
    SDLLogD(@"Sending register secondary transport: %@", message);
    [self sdl_sendDataToTransport:message.data onService:SDLServiceTypeControl];
}


#pragma mark - Send Data

- (void)sendRPC:(SDLRPCMessage *)message {
    if (!message.isPayloadProtected && [self.encryptionLifecycleManager rpcRequiresEncryption:message]) {
        message.payloadProtected = YES;
    }
    
    if (message.isPayloadProtected && !self.encryptionLifecycleManager.isEncryptionReady) {
        SDLLogW(@"Encryption Manager not ready, request not sent (%@)", message);
        return;
    }

    [self sendRPC:message encrypted:message.isPayloadProtected error:nil];
}

- (BOOL)sendRPC:(SDLRPCMessage *)message encrypted:(BOOL)encryption error:(NSError *__autoreleasing *)error {
    NSParameterAssert(message != nil);
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:[message serializeAsDictionary:(Byte)[SDLGlobals sharedGlobals].protocolVersion.major] options:kNilOptions error:error];

    if (error != nil) {
        SDLLogW(@"Error encoding JSON data: %@", *error);
    }
    
    NSData *messagePayload = nil;
    SDLLogV(@"Sending RPC: %@", message);

    // Build the message payload. Include the binary header if necessary
    // VERSION DEPENDENT CODE
    switch ([SDLGlobals sharedGlobals].protocolVersion.major) {
        case 1: {
            // No binary header in version 1
            messagePayload = jsonData;
        } break;
        case 2: // Fallthrough
        case 3: // Fallthrough
        case 4: // Fallthrough
        case 5: {
            // Build a binary header
            // Serialize the RPC data into an NSData
            SDLRPCPayload *rpcPayload = [[SDLRPCPayload alloc] init];
            rpcPayload.functionID = [[[SDLFunctionID sharedInstance] functionIdForName:message.name] unsignedIntValue];
            rpcPayload.jsonData = jsonData;
            rpcPayload.binaryData = message.bulkData;

            // If it's a request or a response, we need to pull out the correlation ID, so we'll downcast
            if ([message isKindOfClass:SDLRPCRequest.class]) {
                rpcPayload.rpcType = SDLRPCMessageTypeRequest;
                rpcPayload.correlationID = [((SDLRPCRequest *)message).correlationID unsignedIntValue];
            } else if ([message isKindOfClass:SDLRPCResponse.class]) {
                rpcPayload.rpcType = SDLRPCMessageTypeResponse;
                rpcPayload.correlationID = [((SDLRPCResponse *)message).correlationID unsignedIntValue];
            } else if ([message isKindOfClass:[SDLRPCNotification class]]) {
                rpcPayload.rpcType = SDLRPCMessageTypeNotification;
            } else {
                NSAssert(NO, @"Unknown message type attempted to send. Type: %@", [message class]);
                return NO;
            }

            // If we're trying to encrypt, try to have the security manager encrypt it. Return if it fails.
            // TODO: (Joel F.)[2016-02-09] We should assert if the service isn't setup for encryption. See [#350](https://github.com/smartdevicelink/sdl_ios/issues/350)
            if (encryption) {
                NSError *encryptError = nil;
                
                messagePayload = [self.securityManager encryptData:rpcPayload.data withError:&encryptError];
                
                if (encryptError) {
                    SDLLogE(@"Error encrypting request! %@", encryptError);
                }
            } else {
                messagePayload = rpcPayload.data;
            }

            if (!messagePayload) {
                return NO;
            }
            
        } break;
        default: {
            NSAssert(NO, @"Attempting to send an RPC based on an unknown version number: %@, message: %@", @([SDLGlobals sharedGlobals].protocolVersion.major), message);
        } break;
    }

    // Build the protocol level header & message
    SDLProtocolHeader *header = [SDLProtocolHeader headerForVersion:(UInt8)[SDLGlobals sharedGlobals].protocolVersion.major];
    header.encrypted = encryption;
    header.frameType = SDLFrameTypeSingle;
    header.serviceType = (message.bulkData.length <= 0) ? SDLServiceTypeRPC : SDLServiceTypeBulkData;
    header.frameData = SDLFrameInfoSingleFrame;
    header.sessionID = [self sdl_retrieveSessionIDforServiceType:SDLServiceTypeRPC];

    // V2+ messages need to have message ID property set.
    if ([SDLGlobals sharedGlobals].protocolVersion.major >= 2) {
        [((SDLV2ProtocolHeader *)header) setMessageID:++_messageID];
    }

    SDLProtocolMessage *protocolMessage = [SDLProtocolMessage messageWithHeader:header andPayload:messagePayload];

    // See if the message is small enough to send in one transmission. If not, break it up into smaller messages and send.
    if (protocolMessage.size < [[SDLGlobals sharedGlobals] mtuSizeForServiceType:SDLServiceTypeRPC]) {
        SDLLogV(@"Sending protocol message: %@", protocolMessage);
        [self sdl_sendDataToTransport:protocolMessage.data onService:SDLServiceTypeRPC];
    } else {
        NSArray<SDLProtocolMessage *> *messages = [SDLProtocolMessageDisassembler disassemble:protocolMessage withLimit:[[SDLGlobals sharedGlobals] mtuSizeForServiceType:SDLServiceTypeRPC]];
        for (SDLProtocolMessage *smallerMessage in messages) {
            SDLLogV(@"Sending protocol message: %@", smallerMessage);
            [self sdl_sendDataToTransport:smallerMessage.data onService:SDLServiceTypeRPC];
        }
    }

    return YES;
}

// Use for normal messages
- (void)sdl_sendDataToTransport:(NSData *)data onService:(NSInteger)priority {
    [_prioritizedCollection addObject:data withPriority:priority];

    NSData *dataToTransmit = nil;
    while (dataToTransmit = (NSData *)[self->_prioritizedCollection nextObject]) {
        [self.transport sendData:dataToTransmit];
    }
}

- (void)sendRawData:(NSData *)data withServiceType:(SDLServiceType)serviceType {
    [self sdl_sendRawData:data onService:serviceType encryption:NO];
}

- (void)sendEncryptedRawData:(NSData *)data onService:(SDLServiceType)serviceType {
    [self sdl_sendRawData:data onService:serviceType encryption:YES];
}

- (void)sdl_sendRawData:(NSData *)data onService:(SDLServiceType)service encryption:(BOOL)encryption {
    SDLV2ProtocolHeader *header = [[SDLV2ProtocolHeader alloc] initWithVersion:(UInt8)[SDLGlobals sharedGlobals].protocolVersion.major];
    header.encrypted = encryption;
    header.frameType = SDLFrameTypeSingle;
    header.serviceType = service;
    header.sessionID = [self sdl_retrieveSessionIDforServiceType:service];
    header.messageID = ++_messageID;

    if (encryption && data.length) {
        NSError *encryptError = nil;
        data = [self.securityManager encryptData:data withError:&encryptError];

        if (encryptError) {
            SDLLogE(@"Error attempting to encrypt raw data for service: %@, error: %@", @(service), encryptError);
        }
    }

    SDLProtocolMessage *message = [SDLProtocolMessage messageWithHeader:header andPayload:data];

    if (message.size < [[SDLGlobals sharedGlobals] mtuSizeForServiceType:service]) {
        SDLLogV(@"Sending protocol message: %@", message);
        [self sdl_sendDataToTransport:message.data onService:header.serviceType];
    } else {
        NSArray<SDLProtocolMessage *> *messages = [SDLProtocolMessageDisassembler disassemble:message withLimit:[[SDLGlobals sharedGlobals] mtuSizeForServiceType:service]];
        for (SDLProtocolMessage *smallerMessage in messages) {
            SDLLogV(@"Sending protocol message: %@", smallerMessage);
            [self sdl_sendDataToTransport:smallerMessage.data onService:header.serviceType];
        }
    }
}


#pragma mark - Receive and Process Data

// Turn received bytes into message objects.
- (void)sdl_handleBytesFromTransport:(NSData *)receivedData {
    // Initialize the receive buffer which will contain bytes while messages are constructed.
    if (self.receiveBuffer == nil) {
        self.receiveBuffer = [NSMutableData dataWithCapacity:(4 * [[SDLGlobals sharedGlobals] mtuSizeForServiceType:SDLServiceTypeRPC])];
    }

    // Save the data
    [self.receiveBuffer appendData:receivedData];

    [self sdl_processMessages];
}

- (void)sdl_processMessages {
    UInt8 incomingVersion = [SDLProtocolHeader determineVersion:self.receiveBuffer];

    // If we have enough bytes, create the header.
    SDLProtocolHeader *header = [SDLProtocolHeader headerForVersion:incomingVersion];
    NSUInteger headerSize = header.size;
    if (self.receiveBuffer.length >= headerSize) {
        [header parse:self.receiveBuffer];
    } else {
        return;
    }

    // If we have enough bytes, finish building the message.
    SDLProtocolMessage *message = nil;
    NSUInteger payloadSize = header.bytesInPayload;
    NSUInteger messageSize = headerSize + payloadSize;
    if (self.receiveBuffer.length >= messageSize) {
        NSUInteger payloadOffset = headerSize;
        NSUInteger payloadLength = payloadSize;
        NSData *payload = [self.receiveBuffer subdataWithRange:NSMakeRange(payloadOffset, payloadLength)];

        // If the message in encrypted and there is payload, try to decrypt it
        if (header.encrypted && payload.length) {
            NSError *decryptError = nil;
            payload = [self.securityManager decryptData:payload withError:&decryptError];

            if (decryptError) {
                SDLLogE(@"Error attempting to decrypt a payload with error: %@", decryptError);
                return;
            }
        }

        message = [SDLProtocolMessage messageWithHeader:header andPayload:payload];
    } else {
        // Need to wait for more bytes.
        SDLLogV(@"Protocol header complete, message incomplete, waiting for %ld more bytes. Header: %@", (long)(messageSize - self.receiveBuffer.length), header);
        return;
    }

    // Need to maintain the receiveBuffer, remove the bytes from it which we just processed.
    self.receiveBuffer = [[self.receiveBuffer subdataWithRange:NSMakeRange(messageSize, self.receiveBuffer.length - messageSize)] mutableCopy];

    // Pass on the message to the message router.
    [self.messageRouter handleReceivedMessage:message protocol:self];

    // Call recursively until the buffer is empty or incomplete message is encountered
    if (self.receiveBuffer.length > 0) {
        [self sdl_processMessages];
    }
}


#pragma mark - SDLProtocolDelegate from SDLReceivedProtocolMessageRouter

- (void)protocol:(SDLProtocol *)protocol didReceiveStartServiceACK:(SDLProtocolMessage *)startServiceACK {
    SDLLogD(@"Received start service ACK: %@", startServiceACK);

    // V5+ Packet
    if (startServiceACK.header.version >= 5) {
        switch (startServiceACK.header.serviceType) {
            case SDLServiceTypeRPC: {
                SDLControlFramePayloadRPCStartServiceAck *startServiceACKPayload = [[SDLControlFramePayloadRPCStartServiceAck alloc] initWithData:startServiceACK.payload];

                if (startServiceACKPayload.mtu != SDLControlFrameInt64NotFound) {
                    [[SDLGlobals sharedGlobals] setDynamicMTUSize:(NSUInteger)startServiceACKPayload.mtu forServiceType:startServiceACK.header.serviceType];
                }
                if (startServiceACKPayload.hashId != SDLControlFrameInt32NotFound) {
                    self.hashId = startServiceACKPayload.hashId;
                }

                [SDLGlobals sharedGlobals].maxHeadUnitProtocolVersion = (startServiceACKPayload.protocolVersion != nil) ? [SDLVersion versionWithString:startServiceACKPayload.protocolVersion] : [SDLVersion versionWithMajor:startServiceACK.header.version minor:0 patch:0];

                self.authToken = [SDLGlobals.sharedGlobals.maxHeadUnitProtocolVersion isGreaterThanOrEqualToVersion:[[SDLVersion alloc] initWithMajor:5 minor:2 patch:0]] ? startServiceACKPayload.authToken : nil;

                // TODO: Hash id?
            } break;
            case SDLServiceTypeAudio: {
                SDLControlFramePayloadRPCStartServiceAck *startServiceACKPayload = [[SDLControlFramePayloadRPCStartServiceAck alloc] initWithData:startServiceACK.payload];
                
                if (startServiceACKPayload.mtu != SDLControlFrameInt64NotFound) {
                    [[SDLGlobals sharedGlobals] setDynamicMTUSize:(NSUInteger)startServiceACKPayload.mtu forServiceType:SDLServiceTypeAudio];
                }
            } break;
            case SDLServiceTypeVideo: {
                SDLControlFramePayloadRPCStartServiceAck *startServiceACKPayload = [[SDLControlFramePayloadRPCStartServiceAck alloc] initWithData:startServiceACK.payload];
                
                if (startServiceACKPayload.mtu != SDLControlFrameInt64NotFound) {
                    [[SDLGlobals sharedGlobals] setDynamicMTUSize:(NSUInteger)startServiceACKPayload.mtu forServiceType:SDLServiceTypeVideo];
                }
            } break;
            default:
                break;
        }
    } else { // V4 and below packet
        switch (startServiceACK.header.serviceType) {
            case SDLServiceTypeRPC: {
                [SDLGlobals sharedGlobals].maxHeadUnitProtocolVersion = [SDLVersion versionWithMajor:startServiceACK.header.version minor:0 patch:0];
            } break;
            default:
                break;
        }
    }

    // Store the header of this service away for future use
    self.serviceHeaders[@(startServiceACK.header.serviceType)] = [startServiceACK.header copy];

    // Pass along to all the listeners
    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveStartServiceACK:)]) {
            [listener protocol:protocol didReceiveStartServiceACK:startServiceACK];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveStartServiceNAK:(SDLProtocolMessage *)startServiceNAK {
    [self sdl_logControlNAKPayload:startServiceNAK];

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveStartServiceNAK:)]) {
            [listener protocol:protocol didReceiveStartServiceNAK:startServiceNAK];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveEndServiceACK:(SDLProtocolMessage *)endServiceACK {
    SDLLogD(@"End service ACK: %@", endServiceACK);
    // Remove the session id
    [self.serviceHeaders removeObjectForKey:@(endServiceACK.header.serviceType)];

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveEndServiceACK:)]) {
            [listener protocol:protocol didReceiveEndServiceACK:endServiceACK];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveEndServiceNAK:(SDLProtocolMessage *)endServiceNAK {
    [self sdl_logControlNAKPayload:endServiceNAK];

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveEndServiceNAK:)]) {
            [listener protocol:protocol didReceiveEndServiceNAK:endServiceNAK];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveRegisterSecondaryTransportACK:(SDLProtocolMessage *)registerSecondaryTransportACK {
    SDLLogD(@"Register Secondary Transport ACK: %@", registerSecondaryTransportACK);

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveRegisterSecondaryTransportACK:)]) {
            [listener protocol:protocol didReceiveRegisterSecondaryTransportACK:registerSecondaryTransportACK];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveRegisterSecondaryTransportNAK:(SDLProtocolMessage *)registerSecondaryTransportNAK {
    [self sdl_logControlNAKPayload:registerSecondaryTransportNAK];

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveRegisterSecondaryTransportNAK:)]) {
            [listener protocol:protocol didReceiveRegisterSecondaryTransportNAK:registerSecondaryTransportNAK];
        }
    }
}

- (void)handleHeartbeatForSession:(Byte)session {
    SDLLogV(@"Received a heartbeat");

    // Respond with a heartbeat ACK
    SDLProtocolHeader *header = [SDLProtocolHeader headerForVersion:(UInt8)[SDLGlobals sharedGlobals].protocolVersion.major];
    header.frameType = SDLFrameTypeControl;
    header.serviceType = SDLServiceTypeControl;
    header.frameData = SDLFrameInfoHeartbeatACK;
    header.sessionID = session;
    SDLProtocolMessage *message = [SDLProtocolMessage messageWithHeader:header andPayload:nil];
    [self sdl_sendDataToTransport:message.data onService:header.serviceType];

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(handleHeartbeatForSession:)]) {
            [listener handleHeartbeatForSession:session];
        }
    }
}

- (void)handleHeartbeatACK {
    SDLLogV(@"Received a heartbeat ACK");

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(handleHeartbeatACK)]) {
            [listener handleHeartbeatACK];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveTransportEventUpdate:(SDLProtocolMessage *)transportEventUpdate {
    SDLLogD(@"Received a transport event update: %@", transportEventUpdate);

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveTransportEventUpdate:)]) {
            [listener protocol:protocol didReceiveTransportEventUpdate:transportEventUpdate];
        }
    }
}

- (void)protocol:(SDLProtocol *)protocol didReceiveMessage:(SDLProtocolMessage *)msg {
    // Control service (but not control frame type) messages are TLS handshake messages
    if (msg.header.serviceType == SDLServiceTypeControl) {
        [self sdl_processSecurityMessage:msg];
        return;
    }

    SDLLogV(@"Other protocol message received: %@", msg);

    NSArray<id<SDLProtocolDelegate>> *listeners = [self sdl_getProtocolListeners];
    for (id<SDLProtocolDelegate> listener in listeners) {
        if ([listener respondsToSelector:@selector(protocol:didReceiveMessage:)]) {
            [listener protocol:protocol didReceiveMessage:msg];
        }
    }
}

- (void)sdl_logControlNAKPayload:(SDLProtocolMessage *)nakMessage {
    switch (nakMessage.header.frameData) {
        case SDLFrameInfoStartServiceNACK: // fallthrough
        case SDLFrameInfoEndServiceNACK: {
            if (nakMessage.header.version >= 5) {
                SDLControlFramePayloadNak *endServiceNakPayload = [[SDLControlFramePayloadNak alloc] initWithData:nakMessage.payload];
                SDLLogE(@"%@ service NAK'd, service type: %@, payload: %@", (nakMessage.header.frameData == SDLFrameInfoStartServiceNACK) ? @"Start" : @"End", @(nakMessage.header.serviceType), endServiceNakPayload);
            } else {
                SDLLogE(@"NAK received message: %@", nakMessage);
            }
        } break;
        case SDLFrameInfoRegisterSecondaryTransportNACK: {
            SDLControlFramePayloadRegisterSecondaryTransportNak *payload = [[SDLControlFramePayloadRegisterSecondaryTransportNak alloc] initWithData:nakMessage.payload];
            SDLLogE(@"Register Secondary Transport NAK'd, reason: %@", payload.reason);
        } break;
        default: break;
    }
}

- (NSArray<id<SDLProtocolDelegate>> *)sdl_getProtocolListeners {
    @synchronized(self.protocolDelegateTable) {
        return self.protocolDelegateTable.allObjects;
    }
}


#pragma mark - TLS Handshake

// TODO: These should be split out to a separate class to be tested properly
- (void)sdl_processSecurityMessage:(SDLProtocolMessage *)clientHandshakeMessage {
    SDLLogD(@"Received a security message: %@", clientHandshakeMessage);

    if (self.securityManager == nil) {
        SDLLogE(@"Failed to process security message because no security manager is set.");
        return;
    }

    // Misformatted handshake message, something went wrong
    if (clientHandshakeMessage.payload.length <= 12) {
        SDLLogE(@"Security message is malformed, less than 12 bytes. It does not have a protocol header.");
    }

    // Tear off the binary header of the client protocol message to get at the actual TLS handshake
    // TODO: (Joel F.)[2016-02-15] Should check for errors
    NSData *clientHandshakeData = [clientHandshakeMessage.payload subdataWithRange:NSMakeRange(12, (clientHandshakeMessage.payload.length - 12))];

    // Ask the security manager for server data based on the client data sent
    NSError *handshakeError = nil;
    NSData *serverHandshakeData = [self.securityManager runHandshakeWithClientData:clientHandshakeData error:&handshakeError];

    // If the handshake went bad and the security library ain't happy, send over the failure to the module. This should result in an ACK with encryption off.
    SDLProtocolMessage *serverSecurityMessage = nil;
    if (serverHandshakeData == nil) {
        SDLLogE(@"Error running TLS handshake procedure. Sending error to module. Error: %@", handshakeError);

        serverSecurityMessage = [self.class sdl_serverSecurityFailedMessageWithClientMessageHeader:clientHandshakeMessage.header messageId:++_messageID];
    } else {
        // The handshake went fine, send the module the remaining handshake data
        serverSecurityMessage = [self.class sdl_serverSecurityHandshakeMessageWithData:serverHandshakeData clientMessageHeader:clientHandshakeMessage.header messageId:++_messageID];
    }

    // Send the response or error message. If it's an error message, the module will ACK the Start Service without encryption. If it's a TLS handshake message, the module will ACK with encryption
    SDLLogD(@"Sending security message: %@", serverSecurityMessage);
    [self sdl_sendDataToTransport:serverSecurityMessage.data onService:SDLServiceTypeControl];
}

+ (SDLProtocolMessage *)sdl_serverSecurityHandshakeMessageWithData:(NSData *)data clientMessageHeader:(SDLProtocolHeader *)clientHeader messageId:(UInt32)messageId {
    // This can't possibly be a v1 header because v1 does not have control protocol messages
    SDLV2ProtocolHeader *serverMessageHeader = [SDLProtocolHeader headerForVersion:clientHeader.version];
    serverMessageHeader.encrypted = NO;
    serverMessageHeader.frameType = SDLFrameTypeSingle;
    serverMessageHeader.serviceType = SDLServiceTypeControl;
    serverMessageHeader.frameData = SDLFrameInfoSingleFrame;
    serverMessageHeader.sessionID = clientHeader.sessionID;
    serverMessageHeader.messageID = messageId;

    // For a control service packet, we need a binary header with a function ID corresponding to what type of packet we're sending.
    SDLRPCPayload *serverTLSPayload = [[SDLRPCPayload alloc] init];
    serverTLSPayload.functionID = 0x01; // TLS Handshake message
    serverTLSPayload.rpcType = 0x00;
    serverTLSPayload.correlationID = 0x00;
    serverTLSPayload.binaryData = data;

    NSData *binaryData = serverTLSPayload.data;

    return [SDLProtocolMessage messageWithHeader:serverMessageHeader andPayload:binaryData];
}

+ (SDLProtocolMessage *)sdl_serverSecurityFailedMessageWithClientMessageHeader:(SDLProtocolHeader *)clientHeader messageId:(UInt32)messageId {
    // This can't possibly be a v1 header because v1 does not have control protocol messages
    SDLV2ProtocolHeader *serverMessageHeader = [SDLProtocolHeader headerForVersion:clientHeader.version];
    serverMessageHeader.encrypted = NO;
    serverMessageHeader.frameType = SDLFrameTypeSingle;
    serverMessageHeader.serviceType = SDLServiceTypeControl;
    serverMessageHeader.frameData = SDLFrameInfoSingleFrame;
    serverMessageHeader.sessionID = clientHeader.sessionID;
    serverMessageHeader.messageID = messageId;

    // For a control service packet, we need a binary header with a function ID corresponding to what type of packet we're sending.
    SDLRPCPayload *serverTLSPayload = [[SDLRPCPayload alloc] init];
    serverTLSPayload.functionID = 0x02; // TLS Error message
    serverTLSPayload.rpcType = 0x02;
    serverTLSPayload.correlationID = 0x00;

    NSData *binaryData = serverTLSPayload.data;

    // TODO: (Joel F.)[2016-02-15] This is supposed to have some JSON data and json data size
    return [SDLProtocolMessage messageWithHeader:serverMessageHeader andPayload:binaryData];
}

@end

NS_ASSUME_NONNULL_END