/*
 * Listen on a given port and recieve files sent to that port.
 *
 * This is an example program so feel free to adapt it for your own use.
 * 
 * Many thanks to all the people who contributed to this.
 * In particular, Rahul <master_4_master@yahoo.com> who provided 
 * some code to start with and Cliff Green <cliffg@codewrangler.net>
 * for his comments.
 *  
 * If anyone can improve on this example please send me a copy,
 * also post it to the boost users group <boost-users@lists.boost.org>
 *
 * Thankyou, Andrew Maclean <andrew.amaclean@gmail.com>
 * 2009-02-04
 */

#ifdef _WIN32 
# define _WIN32_WINNT 0x0501 
#endif 
#include <boost/asio.hpp> 
#include <boost/array.hpp> 
#include <boost/filesystem.hpp> 
#include <boost/bind.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/lexical_cast.hpp>
#include <vector>
#include <string> 
#include <fstream> 
#include <sstream> 
#include <iostream> 
#include <cstdlib>


//! tcp_connection
/*!
 * We will use shared_ptr and enable_shared_from_this because we want to keep the 
 * tcp_connection object alive as long as there is an operation that refers to it.
 *
 * The received data looks like this: <filename>\n<filecontents>
 *
 */
class tcp_connection
  : public boost::enable_shared_from_this<tcp_connection>
{
public:

  typedef boost::shared_ptr<tcp_connection> pointer;

  static pointer create(boost::asio::io_service& io_service)
  {
    return pointer(new tcp_connection(io_service));
  }

  boost::asio::ip::tcp::socket& socket()
  {
    return socket_;
  }

  void start()
  {
    boost::asio::async_read(socket_, boost::asio::buffer(buffer_),
      boost::bind(&tcp_connection::read_handler, shared_from_this(),
      boost::asio::placeholders::error,
      boost::asio::placeholders::bytes_transferred));
  }

  void read_handler(const boost::system::error_code &ec, std::size_t bytes_transferred) 
  { 
    bytes_ += bytes_transferred;
	  if (!ec || ec == boost::asio::error::eof) 
	  { 
		  std::string data(buffer_.data(), bytes_transferred); 
		  if (filename_.empty()) 
		  { 
			  std::istringstream iss(data); 
			  std::getline(iss, filename_); 
			  file_ = data; 
			  file_.erase(0, filename_.size() + 1); 
			  filename_ = boost::filesystem::path(filename_).filename();
        // Ooen the file.
        ofs_.open(filename_.c_str(), std::ios::out | std::ios::binary); 
			  if (ofs_) 
			  { 
				  ofs_ << file_;
          ofs_.flush();
			  } 
			  else 
        {
				  std::cerr << filename_ << " couldn't be created" << std::endl;
          boost::throw_exception( boost::filesystem::wfilesystem_error(
          "file creation error",
          boost::system::error_code( boost::system::posix::invalid_argument, boost::system::system_category ) ) );
        }
		  } 
		  else 
		  { 
        ofs_ << data;
        ofs_.flush();
		  } 

		  if (!ec) 
			  boost::asio::async_read(socket_, boost::asio::buffer(buffer_), 
          boost::bind(&tcp_connection::read_handler, shared_from_this(),
          boost::asio::placeholders::error,
          boost::asio::placeholders::bytes_transferred)); 
		  else 
		  {
          // Bytes received = filename_.size()+1+file_size_
				  std::cout << filename_ << " received from " << socket_.remote_endpoint() << " " << bytes_ << " bytes." << std::endl; 
		  } 
	  } 
	  else
		  std::cerr << "read_handler error: " << ec << " - " << ec.message() << std::endl;
  } 

private:
  tcp_connection(boost::asio::io_service& io_service)
    : socket_(io_service)
    , bytes_(0)
  {
  }

  std::string filename_; 
  std::string file_; 
  boost::asio::ip::tcp::socket socket_; 
  boost::array<char, 4096> buffer_;
  size_t bytes_;
  std::ofstream ofs_;
};


class tcp_server
{
public:
  //! An acceptor is initialised in the constructor to listen on the chosen port.
  tcp_server(boost::asio::io_service& io_service, unsigned int &port)
    : acceptor_(io_service, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port))
  {
    start_accept();
  }

private:

  //! Create a socket and initiate an asynchronous accept operation to wait for a new connection. 
  void start_accept()
  {
    tcp_connection::pointer new_connection =
      tcp_connection::create(acceptor_.io_service());

    acceptor_.async_accept(new_connection->socket(),
        boost::bind(&tcp_server::handle_accept, this, new_connection,
          boost::asio::placeholders::error));
  }

  /*! 
   * This is called when the asynchronous accept operation initiated by start_accept() finishes. 
   * It services the client request, and then calls start_accept() to initiate the next accept operation.
   */
  void handle_accept(tcp_connection::pointer new_connection,
      const boost::system::error_code& error)
  {
    if (!error)
    {
      new_connection->start();
      start_accept();
    }
    else
    {
      throw(error);
    }
  }

  boost::asio::ip::tcp::acceptor acceptor_;
};

class setup_server
{
public:
  setup_server(std::string const & port)
  {
    boost::system::error_code ec;
    std::cout << "Host: " << boost::asio::ip::host_name() << std::endl;
    std::cout << "Listening on port: " << port << std::endl;
    boost::asio::ip::tcp::resolver::query query(boost::asio::ip::host_name(), port); 
    boost::asio::io_service io_service; 
	  boost::asio::ip::tcp::resolver resolver(io_service); 
	  boost::asio::ip::tcp::resolver::iterator it = resolver.resolve(query,ec); 
    if (ec)
    {
      throw(ec);
    }

    // Look at what connections we have.
	  boost::asio::ip::tcp::resolver::iterator end; 
	  while (it != end) 
	  { 
		  std::cout << it->endpoint().address() << std::endl;
		  ++it; 
	  }
    unsigned int p = boost::lexical_cast<unsigned int>(port);
    tcp_server server(io_service,p);
    io_service.run();
  }

private:
};

int main(int argc, const char *argv[]) 
{ 
  if (argc < 2) 
  { 
    std::cerr << "You must provide the port to listen on." << std::endl;
    std::cerr << "Make sure that the port is not blocked by the firewall." << std::endl; 
    std::cerr << "Syntax: " << std::endl;
	  std::cerr << argv[0] << " <port>" << std::endl; 
	  return EXIT_SUCCESS; 
  } 

  try
  {
    setup_server server_setup(argv[1]);
  }
  catch (boost::system::error_code ec)
  {
    std::cerr << "error: " << ec << " - " << ec.message() << std::endl; 
    return EXIT_FAILURE;
  }
  catch (std::exception& e)
  {
    std::cerr << e.what() << std::endl;
    return EXIT_FAILURE;
  }
  return EXIT_SUCCESS;
}