/*
 *  network_udp.cpp - UDP network functions (corresponds to AppleTalk DDP)

	Copyright (C) 1991-2001 and beyond by Bungie Studios, Inc.
	and the "Aleph One" developers.
 
	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.

	This license is contained in the file "COPYING",
	which is included with this source code; it is available online at
	http://www.gnu.org/licenses/gpl.html

*/
/*
 *  network_udp.cpp - UDP network functions (corresponds to AppleTalk DDP)
 *
 *  Written in 2000 by Christian Bauer
 *
 *  Sept-Nov 2001 (Woody Zenfell): a few additions to implement socket-listening thread.
 *
 *  May 18, 2003 (Woody Zenfell): now uses passed-in port number for local socket.
 */

#if !defined(DISABLE_NETWORKING)

#include "cseries.h"
#include "sdl_network.h"
#include "network_private.h"

#include <SDL2/SDL_thread.h>

#include "thread_priority_sdl.h"
#include "mytm.h" // mytm_mutex stuff

// Global variables (most comments and "sSomething" variables are ZZZ)
// Storage for incoming packet data
static UDPpacket*		sUDPPacketBuffer	= NULL;

// Storage for the DDP packet we pass back to the handler proc
static DDPPacketBuffer		ddpPacketBuffer;

// Keep track of our one sending/receiving socket
static UDPsocket 		sSocket			= NULL;

// Keep track of the socket-set the receiving thread uses (so we don't have to allocate/free it in that thread)
static	SDLNet_SocketSet	sSocketSet		= NULL;

// Keep track of the function to call when we receive data
static PacketHandlerProcPtr	sPacketHandler		= NULL;

// Keep track of the receiving thread
static SDL_Thread*		sReceivingThread	= NULL;

// See if the receiving thread should exit
static volatile bool		sKeepListening		= false;


// ZZZ: the socket listening thread loops in this function.  It calls the registered
// packet handler when it gets something.
static int
receive_thread_function(void*) {
    while(true) {
        // We listen with a timeout so we can shut ourselves down when needed.
        int theResult = SDLNet_CheckSockets(sSocketSet, 1000);
        
        if(!sKeepListening)
            break;
        
        if(theResult > 0 && take_mytm_mutex()) {
                theResult = SDLNet_UDP_Recv(sSocket, sUDPPacketBuffer);
                if(theResult > 0) {
                        ddpPacketBuffer.protocolType	= kPROTOCOL_TYPE;
                        ddpPacketBuffer.sourceAddress	= sUDPPacketBuffer->address;
                        ddpPacketBuffer.datagramSize	= sUDPPacketBuffer->len;
                    
                        // Hope the other guy is done using whatever's in there!
                        // (As I recall, all uses happen in sPacketHandler and its progeny, so we should be fine.)
                        memcpy(ddpPacketBuffer.datagramData, sUDPPacketBuffer->data, sUDPPacketBuffer->len);
                    
                        sPacketHandler(&ddpPacketBuffer);
                    }
           release_mytm_mutex();
        }
    }
    
    return 0;
}


/*
 *  Initialize/shutdown module
 */

OSErr NetDDPOpen(void)
{
//fdprintf("NetDDPOpen\n");
	// nothing to do
	return 0;
}

OSErr NetDDPClose(void)
{
//fdprintf("NetDDPClose\n");
	// nothing to do
	return 0;
}


/*
 *  Open socket
 */
// Most of this function by ZZZ.
// Incoming port number should be in network byte order.
OSErr NetDDPOpenSocket(short *ioPortNumber, PacketHandlerProcPtr packetHandler)
{
//fdprintf("NetDDPOpenSocket\n");
	assert(packetHandler);

	// Allocate packet buffer (this is Christian's part)
	assert(!sUDPPacketBuffer);
	sUDPPacketBuffer = SDLNet_AllocPacket(ddpMaxData);
	if (sUDPPacketBuffer == NULL)
		return -1;

        //PORTGUESS
	// Open socket (SDLNet_Open seems to like port in host byte order)
        // NOTE: only SDLNet_UDP_Open wants port in host byte order.  All other uses of port in SDL_net
        // are in network byte order.
	sSocket = SDLNet_UDP_Open(SDL_SwapBE16(*ioPortNumber));
	if (sSocket == NULL) {
		SDLNet_FreePacket(sUDPPacketBuffer);
		sUDPPacketBuffer = NULL;
		return -1;
	}

        // Set up socket set
        sSocketSet = SDLNet_AllocSocketSet(1);
        SDLNet_UDP_AddSocket(sSocketSet, sSocket);
        
        // Set up receiver
        sKeepListening		= true;
        sPacketHandler		= packetHandler;
        sReceivingThread	= SDL_CreateThread(receive_thread_function, "NetDDPOpenSocket_ReceivingThread", NULL);

        // Set receiving thread priority very high
        bool	theResult = BoostThreadPriority(sReceivingThread);
        if(theResult == false)
            fdprintf("warning: BoostThreadPriority() failed; network performance may suffer\n");
        
        //PORTGUESS but we should generally keep port in network order, I think?
	// We really ought to return the "real" port we bound to in *ioPortNumber...
	// for now we just hand back whatever they handed us.
	//*ioPortNumber = *ioPortNumber;
	return 0;
}


/*
 *  Close socket
 */

OSErr NetDDPCloseSocket(short portNumber)
{
//fdprintf("NetDDPCloseSocket\n");
        // ZZZ: shut down receiving thread
        if(sReceivingThread) {
            sKeepListening	= false;
            SDL_WaitThread(sReceivingThread, NULL);
            sReceivingThread	= NULL;
        }

        if(sSocketSet) {
            SDLNet_FreeSocketSet(sSocketSet);
            sSocketSet = NULL;
        }
    
        // (CB's code follows)
	if (sUDPPacketBuffer) {
		SDLNet_FreePacket(sUDPPacketBuffer);
		sUDPPacketBuffer = NULL;

		SDLNet_UDP_Close(sSocket);
		sSocket = NULL;
	}
	return 0;
}


/*
 *  Allocate frame
 */

DDPFramePtr NetDDPNewFrame(void)
{
//fdprintf("NetDDPNewFrame\n");
	DDPFramePtr frame = (DDPFramePtr)malloc(sizeof(DDPFrame));
	if (frame) {
		memset(frame, 0, sizeof(DDPFrame));
		frame->socket = sSocket;
	}
	return frame;
}


/*
 *  Dispose of frame
 */

void NetDDPDisposeFrame(DDPFramePtr frame)
{
//fdprintf("NetDDPDisposeFrame\n");
	if (frame)
		free(frame);
}


/*
 *  Send frame to remote machine
 */

OSErr NetDDPSendFrame(DDPFramePtr frame, const NetAddrBlock *address, short protocolType, short port)
{
//fdprintf("NetDDPSendFrame\n");
	assert(frame->data_size <= ddpMaxData);

	sUDPPacketBuffer->channel = -1;
	memcpy(sUDPPacketBuffer->data, frame->data, frame->data_size);
	sUDPPacketBuffer->len = frame->data_size;
	sUDPPacketBuffer->address = *address;
	return SDLNet_UDP_Send(sSocket, -1, sUDPPacketBuffer) ? 0 : -1;
}

#endif // !defined(DISABLE_NETWORKING)
