/** @file
 * @brief TCPService class header. This class represents a TCP client.
 *
 *
 *
 * @copyright Intra2net AG
 * @license GPLv2
*/

#include "tcp_service.hpp"

typedef boost::shared_ptr<SSLStream> SocketPtr;

using namespace std;


/**
 * Constructor
 * @param _log Logger object.
 * @param io_service Service peer information.
 */
TCPService::TCPService()
    : Socket()
    , IOService()
{
}


/**
 * Default destrucotr.
 */
TCPService::~TCPService()
{
}


/**
 * Initiate a new session with the peer.
 * @param endpoint_iterator The enpoint iterator.
 * @return throws boost::syste::system_error if something went wrong.
 */
void TCPService::connect(const std::string& _host, const std::string& _port)
{
    // Init boost::system::error_code
    boost::system::error_code err_code;

    // Create service object. The IO_Service has to be a member
    //boost::asio::io_service io_service;

    // Init DNS query object
    boost::asio::ip::tcp::resolver service_resolver(IOService);
    boost::asio::ip::tcp::resolver::query dns_query(_host, _port);
    boost::asio::ip::tcp::resolver::iterator end_iter;

    // Perform the DNS query
    boost::asio::ip::tcp::resolver::iterator endpoint_iterator = service_resolver.resolve(dns_query, err_code);
    if ( err_code )
        throw boost::system::system_error(err_code);

    // Init ssl context for service object
    boost::asio::ssl::context ctx(IOService, boost::asio::ssl::context::sslv23);
    ctx.set_verify_mode(boost::asio::ssl::context::verify_none);

    // Initialize the member Socket
    Socket = SocketPtr(new SSLStream(IOService,ctx));

    // Try to connect the Socket through all available endpoints
    if (endpoint_iterator != end_iter)
    {
        do
        {
            Socket->lowest_layer().close();                                 /*lint !e534 */
            Socket->lowest_layer().connect(*endpoint_iterator++, err_code); /*lint !e534 */
        } while ( err_code && (endpoint_iterator != end_iter) );
    }
    if ( err_code )
        throw boost::system::system_error(err_code);

    // Perform SSL handshake
    Socket->handshake(boost::asio::ssl::stream_base::client,err_code); /*lint !e534*/
    if ( err_code )
        throw boost::system::system_error(err_code);

    return;
}


/**
 * Will read all available data and return it as a string.
 * @return The data read from the socket. Throws boost::syste::system_error if something went wrong.
 */
std::string TCPService::read_from_socket()
{
    // Limit stream buffer to 1MB
    //unsigned int max_buff_size = 1024*1024;
    //boost::asio::streambuf stream_buffer(max_buff_size);

    // Do not limit the receive buffer size for reusability. By default, max_size == 18446744073709551615
    boost::asio::streambuf stream_buffer;

    // Init error_code
    boost::system::error_code error_code;

    // Is blocking until all available data was read or buffer is full
    size_t bytes_read = boost::asio::read(*Socket.get(),stream_buffer,boost::asio::transfer_at_least(1),error_code); /*lint !e747 */
    if ( error_code == boost::asio::error::eof )
        throw boost::system::system_error(boost::system::error_code(ECONNABORTED,boost::system::system_category()),"Connection closed by peer.");
    else if (error_code)
        throw boost::system::system_error(error_code);
    else if ( bytes_read == stream_buffer.max_size() )
        throw boost::system::system_error(boost::system::error_code(ENOBUFS,boost::system::system_category()),"Could not read all available data into streambuf.");
    else if ( bytes_read == 0 )
        throw boost::system::system_error(boost::system::error_code(ENODATA,boost::system::system_category()),"No data available on socket.");

    // Copy data from stream buffer to a constant buffer and create a string object from the constant buffer
    boost::asio::streambuf::const_buffers_type const_buffer = stream_buffer.data();
    std::string data_read(boost::asio::buffers_begin(const_buffer), boost::asio::buffers_begin(const_buffer) + bytes_read); /*lint !e713*/

    return data_read;
}


/**
 * Writes out given data to the socket.
 * @param data The data which will be written to the socket.
 * @return Throws boost::syste::system_error if something went wrong.
 */
void TCPService::write_to_socket(const string& data)
{
    // Get the data size which will be written
    size_t data_size = data.size();

    // Init stream_buffer with data
    boost::asio::streambuf stream_buffer(data_size);
    std::ostream request_stream(&stream_buffer);
    request_stream << data;

    // Init error_code
    boost::system::error_code error_code;

    size_t bytes_wrote = boost::asio::write(*Socket.get(), stream_buffer, boost::asio::transfer_at_least(data_size), error_code);
    if (error_code)
        throw boost::system::system_error(error_code);
    else if ( bytes_wrote != data_size )
        throw boost::system::system_error(boost::system::error_code(ENOBUFS,boost::system::system_category()),"Could not write all data to the socket.");

    return;
}


/**
 * Will close the session.
 * @return 0 if all is fine, throws boost::syste::system_error if something went wrong.
 */
void TCPService::close()
{
    boost::system::error_code error_code;

    // Shutdown send and receive channel on socket. This results in sending FIN flag.
    Socket->lowest_layer().shutdown(boost::asio::ip::tcp::socket::shutdown_both,error_code); /*lint !e534*/
    if ( error_code )
        throw boost::system::system_error(error_code);

    // Closing the session.
    Socket->lowest_layer().close( error_code ); /*lint !e534*/
    if ( error_code )
        throw boost::system::system_error(error_code);

    return;
}