/*
 *	C++ sockets on Unix and Windows
 *	Copyright (C) 2002	<unknown>
 *	Copyright (C) 2010	Uditha Atukorala
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef SL_SOCKET_H
#define SL_SOCKET_H

#include <string>			// For string
#include <exception>		// For exception class
#include <vector>			// For vectors

#ifdef WIN32
	#include <winsock.h>			// For socket(), connect(), send(), and recv()
	typedef int socklen_t;
	typedef char raw_type;			// Type used for raw data on this platform
#else
	#include <netinet/in.h>         // For sockaddr_in
	typedef void raw_type;			// Type used for raw data on this platform
#endif

using namespace std;

namespace socketlibrary {

/**
 * Function to fill in address structure given an address and port
 */
void fillAddr(const string &address, unsigned short port, sockaddr_in &addr);

/**
 *   Signals a problem with the execution of a socket call.
 */
class SocketException : public exception {
public:
	/**
	*   Construct a SocketException with a explanatory message.
	*   @param message explanatory message
	*   @param incSysMsg true if system message (from strerror(errno))
	*   should be postfixed to the user provided message
	*/
	SocketException(const string &message, bool inclSysMsg = false) throw();

	/**
	*   Provided just to guarantee that no exceptions are thrown.
	*/
	~SocketException() throw();

	/**
	*   Get the exception message
	*   @return exception message
	*/
	const char *what() const throw();

private:
	string userMessage;		// Exception message
};


/**
 *   Base class representing basic communication endpoint
 */
class Socket {
public:
	/**
	*   Close and deallocate this socket
	*/
	~Socket();

	/**
	*   Get the local address
	*   @return local address of socket
	*   @exception SocketException thrown if fetch fails
	*/
	string getLocalAddress() throw(SocketException);

	/**
	*   Get the local port
	*   @return local port of socket
	*   @exception SocketException thrown if fetch fails
	*/
	unsigned short getLocalPort() throw(SocketException);

	/**
	*   Set the local port to the specified port and the local address
	*   to any interface
	*   @param localPort local port
	*   @exception SocketException thrown if setting local port fails
	*/
	void setLocalPort(unsigned short localPort) throw(SocketException);

	/**
	*   Set the local port to the specified port and the local address
	*   to the specified address.  If you omit the port, a random port 
	*   will be selected.
	*   @param localAddress local address
	*   @param localPort local port
	*   @exception SocketException thrown if setting local port or address fails
	*/
	void setLocalAddressAndPort(const string &localAddress, unsigned short localPort = 0) throw(SocketException);

	/**
	*   If WinSock, unload the WinSock DLLs; otherwise do nothing.  We ignore
	*   this in our sample client code but include it in the library for
	*   completeness.  If you are running on Windows and you are concerned
	*   about DLL resource consumption, call this after you are done with all
	*   Socket instances.  If you execute this on Windows while some instance of
	*   Socket exists, you are toast.  For portability of client code, this is 
	*   an empty function on non-Windows platforms so you can always include it.
	*   @param buffer buffer to receive the data
	*   @param bufferLen maximum number of bytes to read into buffer
	*   @return number of bytes read, 0 for EOF, and -1 for error
	*   @exception SocketException thrown WinSock clean up fails
	*/
	static void cleanUp() throw(SocketException);

	/**
	*   Resolve the specified service for the specified protocol to the
	*   corresponding port number in host byte order
	*   @param service service to resolve (e.g., "http")
	*   @param protocol protocol of service to resolve.  Default is "tcp".
	*/
	static unsigned short resolveService(const string &service, const string &protocol = "tcp");
	
private:
	// Prevent the user from trying to use value semantics on this object
	Socket(const Socket &sock);
	void operator=(const Socket &sock);

protected:
	int sock;				// Socket descriptor
	Socket(int type, int protocol) throw(SocketException);
	Socket(int sock);
};

/**
 *   Socket which is able to connect, send, and receive
 */
class CommunicatingSocket : public Socket {
public:
	/**
	*   Establish a socket connection with the given foreign
	*   address and port
	*   @param foreignAddress foreign address (IP address or name)
	*   @param foreignPort foreign port
	*   @exception SocketException thrown if unable to establish connection
	*/
	void connect(const string &foreignAddress, unsigned short foreignPort) throw(SocketException);

	/**
	*   Write the given buffer to this socket.  Call connect() before
	*   calling send()
	*   @param buffer buffer to be written
	*   @param bufferLen number of bytes from buffer to be written
	*   @exception SocketException thrown if unable to send data
	*/
	void send(const void *buffer, int bufferLen) throw(SocketException);

	/**
	*   Read into the given buffer up to bufferLen bytes data from this
	*   socket.  Call connect() before calling recv()
	*   @param buffer buffer to receive the data
	*   @param bufferLen maximum number of bytes to read into buffer
	*   @return number of bytes read, 0 for EOF, and -1 for error
	*   @exception SocketException thrown if unable to receive data
	*/
	int recv(void *buffer, int bufferLen) throw(SocketException);

	/**
	*   Read into the given buffer up to bufferLen bytes data from this
	*   socket but don't remove the read bytes from the socket read buffer.
	*   Call connect() before calling peek()
	*
	*   @param buffer buffer to receive the data
	*   @param bufferLen maximum number of bytes to read into buffer
	*   @return number of bytes read, 0 for EOF, and -1 for error
	*   @exception SocketException thrown if unable to receive data
	*/
	int peek(void *buffer, int bufferLen) throw(SocketException);

	/**
	*   Read a line into the given buffer from this socket.
	*   Call connect() before calling recv()
	*
	*   @param buffer buffer to receive the data
	*   @param bufferLen maximum number of bytes to read into buffer
	*   @param delimiter (optional) end of line delimiter
	*   @return number of bytes read, 0 for EOF, and -1 for error
	*   @exception SocketException thrown if unable to receive data
	*/
	int readLine(char *buffer, int bufferLen, const char delimiter = '\n') throw(SocketException);

	/**
	*   Get the foreign address.  Call connect() before calling recv()
	*   @return foreign address
	*   @exception SocketException thrown if unable to fetch foreign address
	*/
	string getForeignAddress() throw(SocketException);

	/**
	*   Get the foreign port.  Call connect() before calling recv()
	*   @return foreign port
	*   @exception SocketException thrown if unable to fetch foreign port
	*/
	unsigned short getForeignPort() throw(SocketException);

protected:
	CommunicatingSocket(int type, int protocol) throw(SocketException);
	CommunicatingSocket(int newSD);
};

/**
 *   TCP socket for communication with other TCP sockets
 */
class TCPSocket : public CommunicatingSocket {
public:
	/**
	*   Construct a TCP socket with no connection
	*   @exception SocketException thrown if unable to create TCP socket
	*/
	TCPSocket() throw(SocketException);

	/**
	*   Construct a TCP socket with a connection to the given foreign address
	*   and port
	*   @param foreignAddress foreign address (IP address or name)
	*   @param foreignPort foreign port
	*   @exception SocketException thrown if unable to create TCP socket
	*/
	TCPSocket(const string &foreignAddress, unsigned short foreignPort) throw(SocketException);

private:
	friend class TCPServerSocket;	// Access for TCPServerSocket::accept() connection creation
	friend class TCPServerSocketM;	// Access for TCPServerSocketM::accept() connection creation
	TCPSocket(int newSD);
};

/**
 *   TCP socket class for servers
 */
class TCPServerSocket : public Socket {
public:
	/**
	*   Construct a TCP socket for use with a server, accepting connections
	*   on the specified port on any interface
	*   @param localPort local port of server socket, a value of zero will
	*                   give a system-assigned unused port
	*   @param queueLen maximum queue length for outstanding 
	*                   connection requests (default 5)
	*   @exception SocketException thrown if unable to create TCP server socket
	*/
	TCPServerSocket(unsigned short localPort, int queueLen = 5) throw(SocketException);

	/**
	*   Construct a TCP socket for use with a server, accepting connections
	*   on the specified port on the interface specified by the given address
	*   @param localAddress local interface (address) of server socket
	*   @param localPort local port of server socket
	*   @param queueLen maximum queue length for outstanding 
	*                   connection requests (default 5)
	*   @exception SocketException thrown if unable to create TCP server socket
	*/
	TCPServerSocket(const string &localAddress, unsigned short localPort, int queueLen = 5) throw(SocketException);

	/**
	*   Blocks until a new connection is established on this socket or error
	*   @return new connection socket
	*   @exception SocketException thrown if attempt to accept a new connection fails
	*/
	TCPSocket *accept() throw(SocketException);

private:
	void setListen(int queueLen) throw(SocketException);
};

/**
 *   TCP socket class for multi-client servers
 */
class TCPServerSocketM : public TCPServerSocket {
public:

	/**
	*   Construct a TCP socket for use with a server, accepting connections
	*   on the specified port on any interface
	*   @param localPort local port of server socket, a value of zero will
	*                   give a system-assigned unused port
	*   @param queueLen maximum queue length for outstanding 
	*                   connection requests (default 5)
	*   @exception SocketException thrown if unable to create TCP server socket
	*/
	TCPServerSocketM(unsigned short localPort, int queueLen = 5) throw(SocketException);
	
	/**
	*   Blocks until a new connection is established on this socket or error
	*   @return new connection socket
	*   @exception SocketException thrown if attempt to accept a new connection fails
	*/
	TCPSocket *accept() throw(SocketException);
	
	/**
	*   Checks for incoming connections or error
	*   @return boolean (true if incoming connections are present)
	*   @exception SocketException thrown if attempt to check for new connections fail
	*/
	bool pendingConnections() throw(SocketException);
	
	/**
	*   Checks for read waiting clients
	*   @param clients a vector of TCPSocket pointers to get the waiting clients
	*   @return number of clients waiting
	*   @exception SocketException thrown if attempt to check for waiting clients fail
	*/
	int getWaitingClients(vector<TCPSocket *> &clients) throw (SocketException);
	
	/**
	*   Closes the connection to a client
	*   @param client the client TCPSocket to close
	*/
	void closeClientConnection(TCPSocket *client);
	
private:
	fd_set fds_master;		// master file descriptor list
	int fdmax;				// maximum file descriptor number
	
	vector<TCPSocket *> v_clients;
};

/**
  *   UDP socket class
  */
class UDPSocket : public CommunicatingSocket {
public:
	/**
	*   Construct a UDP socket
	*   @exception SocketException thrown if unable to create UDP socket
	*/
	UDPSocket() throw(SocketException);

	/**
	*   Construct a UDP socket with the given local port
	*   @param localPort local port
	*   @exception SocketException thrown if unable to create UDP socket
	*/
	UDPSocket(unsigned short localPort) throw(SocketException);

	/**
	*   Construct a UDP socket with the given local port and address
	*   @param localAddress local address
	*   @param localPort local port
	*   @exception SocketException thrown if unable to create UDP socket
	*/
	UDPSocket(const string &localAddress, unsigned short localPort) throw(SocketException);

	/**
	*   Unset foreign address and port
	*   @return true if disassociation is successful
	*   @exception SocketException thrown if unable to disconnect UDP socket
	*/
	void disconnect() throw(SocketException);

	/**
	*   Send the given buffer as a UDP datagram to the
	*   specified address/port
	*   @param buffer buffer to be written
	*   @param bufferLen number of bytes to write
	*   @param foreignAddress address (IP address or name) to send to
	*   @param foreignPort port number to send to
	*   @return true if send is successful
	*   @exception SocketException thrown if unable to send datagram
	*/
	void sendTo(const void *buffer, int bufferLen, const string &foreignAddress, unsigned short foreignPort) throw(SocketException);

	/**
	*   Read read up to bufferLen bytes data from this socket.  The given buffer
	*   is where the data will be placed
	*   @param buffer buffer to receive data
	*   @param bufferLen maximum number of bytes to receive
	*   @param sourceAddress address of datagram source
	*   @param sourcePort port of data source
	*   @return number of bytes received and -1 for error
	*   @exception SocketException thrown if unable to receive datagram
	*/
	int recvFrom(void *buffer, int bufferLen, string &sourceAddress, unsigned short &sourcePort) throw(SocketException);

	/**
	*   Set the multicast TTL
	*   @param multicastTTL multicast TTL
	*   @exception SocketException thrown if unable to set TTL
	*/
	void setMulticastTTL(unsigned char multicastTTL) throw(SocketException);

	/**
	*   Join the specified multicast group
	*   @param multicastGroup multicast group address to join
	*   @exception SocketException thrown if unable to join group
	*/
	void joinGroup(const string &multicastGroup) throw(SocketException);

	/**
	*   Leave the specified multicast group
	*   @param multicastGroup multicast group address to leave
	*   @exception SocketException thrown if unable to leave group
	*/
	void leaveGroup(const string &multicastGroup) throw(SocketException);

private:
	void setBroadcast();
};

} // End of namespace SocketLibrary

#endif /* !SL_SOCKET_H */