/* $Id: mplayerd.c,v 1.4 2006/01/31 23:14:38 tnn Exp $ */
/* control mplayer by submitting slave commands over tcp/ip */

#define PORT 1234
#define MPLAYER_COMMAND "DISPLAY=:0 mplayer -quiet -slave silent.mp3"

/* uncomment this if it doesn't work */
/* #define DEBUG */ 

/*
 *
 * usage example: 
 *
 * server$ cc -o mplayerd mplayerd.c
 * server$ ./mplayerd &
 *
 * client$ echo 'loadfile /path/to/video.mpeg' | telnet server:1234
 * client$ sleep 10
 * client$ echo 'osd_show_text Hello\ World.' | telnet server:1234
 * client$ sleep 10
 * client$ echo 'seek 0 1' | telnet server:1234
 * 
 *
 * NOTE: You must set MPLAYER_COMMAND to point to a default video or audio
 *       file that will be played until the first loadfile command
 *       has been processed. Also note that no security checks are done,
 *       other than that the "run" command is disabled.
 *
 * Read slave.txt in the mplayer distribution for command syntax.
**/

/**
 * (c) 2006 Tobias Nygren <tnn+mplayerd-c@nygren.pp.se>
 * 
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <stdarg.h>

#ifdef MAX
#undef MAX
#endif
#define MAX(a,b) (((a)>(b))?(a):(b))

static void die (char *format, ...) {

	va_list ap;

	va_start (ap, format);
	fprintf (stderr, "fatal error: ");
	vfprintf (stderr, format, ap);
	fprintf (stderr, "\n");
	va_end (ap);
	exit (1);

}

void dbg (char *format, ...) {
#ifdef DEBUG
	va_list ap;

	va_start (ap, format);
	fprintf (stderr, "debug: ");
	vfprintf (stderr, format, ap);
	fprintf (stderr, "\n");
	va_end (ap);
#endif
}



int main (int argc, char **argv) {

	int mpfd[2];
	int listenfd, clientfd, nfds, connected, mplayer, len, status;
	pid_t pid;
	struct sockaddr_in listensa, clientsa;
	char buf[256];
	socklen_t socklen;
	fd_set rs, ws, es;

	/* listen on server socket */

	listenfd = socket (AF_INET, SOCK_STREAM, 0);
	if (listenfd < 0) die ("socket");

	listensa.sin_family = AF_INET;
	listensa.sin_addr.s_addr = htonl (INADDR_ANY);
	listensa.sin_port = htons (PORT);

	if (bind (listenfd, (struct sockaddr*)&listensa, sizeof(listensa)) < 0)
		die ("bind");
	if (listen (listenfd, 5) < 0)
		die ("listen");

	connected = 0; /* no client connected */
	mplayer = 0; /* no mplayer running */

	/* mainloop */

	dbg ("listening");

	for(;;) {
		FD_ZERO (&rs);
		FD_ZERO (&ws);
		FD_ZERO (&es);
		
		FD_SET (listenfd, &rs);

		nfds = 0;
		nfds = MAX (nfds, listenfd);

		if (connected) {
			FD_SET (clientfd, &rs);
			FD_SET (clientfd, &es);
			nfds = MAX (nfds, clientfd);
		}
		if (mplayer) {
			FD_SET (mpfd[0], &rs);
			FD_SET (mpfd[0], &es);
			nfds = MAX (nfds, mpfd[0]);
		}
		nfds++;

		if (select (nfds, &rs, &ws, &es, NULL) == -1) die ("select");

		if (mplayer) {
			if (FD_ISSET (mpfd[0], &rs)) {

				/* sink characters from mplayer */
				/* detect shutdown by magic character 0 */

				recv (mpfd[0], buf, 1, 0);
				if (buf[0] == 0) {
					dbg ("mplayer shutdown ...");
					if( wait(&status) < 0)
						die("wait");
					close (mpfd[0]);
					close (mpfd[1]);
					dbg ("... completed");
					mplayer = 0;
				}
				fprintf (stderr, "%c", buf[0]);
			}
			if (FD_ISSET (mpfd[0], &es)) {
				die ("exception from mplayer");
			}
		}

		if (FD_ISSET (listenfd, &rs)) {

			/* new connection */
			dbg ("incoming connection");

			if (connected) {

				/* kick out previous client */
				dbg ("kicking out old client");

				shutdown (clientfd, SHUT_RDWR);
				close (clientfd);
			}
			clientfd = accept (listenfd,
					   (struct sockaddr *)&clientsa,
					   &socklen);
			if (clientfd < 0) die("accept");
			dbg ("connected");
			connected = 1;
		}
		if (connected) {
			if (FD_ISSET (clientfd, &rs)) {

				/* incoming command, read it and disconnect */
				dbg ("read command");

				len=recv (clientfd, &buf, 254, 0);
				if(len == -1) die("recv(client)");
				buf[len]=0;
				strtok(buf, "\r");
				strtok(buf, "\n");
				shutdown (clientfd, SHUT_RDWR);
				close (clientfd);
				connected = 0;
				dbg ("disconnected");

				if (!mplayer) {

					/* mplayer not running, start it */
					dbg ("starting mplayer ...");

					if (socketpair (AF_UNIX, SOCK_STREAM,
							0, mpfd) < 0)
						die("socketpair");
					pid = fork();
					if (pid == -1) die("fork");
					if (pid == 0) {
						dup2 (mpfd[1], 0);
						dup2 (mpfd[1], 1);
						dup2 (mpfd[1], 2);
						system (MPLAYER_COMMAND);
						/* magic */
						send (mpfd[1],"\000", 1, 0);
						_exit(0);
					}
					mplayer = 1;
					dbg ("... started");
				}

				/* send command to mplayer */
			        dbg ("command '%s'", buf);

				strcat(buf, "\n");

				if (strncmp (buf, "run", 3))
				   send (mpfd[0], buf, strlen(buf), 0);
			}
			if (FD_ISSET (clientfd, &es)) {

				/* client error, disconnect it */
			        dbg ("client error");

				shutdown (clientfd, SHUT_RDWR);
				close (clientfd);
				connected = 0;
			}
		}
	}
}