/*
 *	IvyDaemon, an Ivy gateway for short-lived agents
 * 
 *	Copyright (C) 1999
 *	Centre d'Études de la Navigation Aérienne
 *
 *	Main file for the client ivyecho
 *
 *	Author(s): Stephane Chatty <chatty@cenatoulouse.dgac.fr>
 *		from code by Patrick Amar <pa@lri.fr>
 *
 *	$Id$
 *
 *	Please refer to file version.h for the
 *	copyright notice regarding this software
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <getopt.h>
#include <string.h>
#include <memory.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#include "ivyd.h"

const char* const servicename = "ivyd";
const char* const port_env_variable = "INIVYD_PORT";
const int default_port = DEFAULT_INIVYD_PORT;

int debug = 0;

void
Usage (const char* progname) {
	fprintf (stderr, "Usage: %s [-b bus (ignored)][-s server] text\n", progname);
	exit (1);
}

/* Get in touch with super-server and retrieve server's port number */
int
GetPort (long addr)
{
	struct servent *serv;
	u_short serv_port;
	struct sockaddr_in sin;
	struct connmsg msg;
	int sock;
	int len;

	/* get service port number */
	serv = getservbyname (servicename, 0);
	if (! serv) {
		char *pp = getenv (port_env_variable);
		serv_port = htons (pp ? atoi (pp) : default_port);
		if (serv_port <= 0)
			exit (0);
	} else
		serv_port = serv -> s_port;

	/* create and bind socket */
	sock = socket (AF_INET, SOCK_DGRAM, 0);
	if (sock == -1) {
		perror ("Can't create socket: ");
		return 0;
	}
	memset (&sin, 0, sizeof sin);
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = INADDR_ANY;
	if (-1 == bind (sock, &sin, sizeof sin)) {
		perror ("Can't bind socket: ");
		goto failed;
	}
	sin.sin_port = serv_port;
	sin.sin_addr.s_addr = addr;

	/* build request */	
	msg.msg_uid = getuid ();
	msg.msg_port = 0;
	msg.msg_type = MSG_CLIENT;

	/* send it */
	if (-1 == sendto (sock, (char *)&msg, sizeof msg, 0, (struct sockaddr *)&sin, sizeof sin)) {
		perror ("Can't send on socket: ");
		goto failed;
	}

	/* wait for reply */
	len = sizeof sin;
	if (-1 == recvfrom (sock, (char *)&msg, sizeof msg, 0, (struct sockaddr *)&sin, &len)) {
		perror ("Can't receive on socket: ");
		goto failed;
	}

	/* OK, we're done, return reply */
	(void) close (sock);
	return (int) msg.msg_port;

failed:
	(void) close (sock);
	return 0;
}

int
ServerOpen (const char *host)
{
	int sock;
	static struct sockaddr_in addr;
	struct hostent *hp;

	/* determine host name and address */
	if (!host)
		host = getenv ("IVYD");

	if (!host)
		host = "localhost";

	hp = gethostbyname (host);
	if (hp == 0) {
		fprintf (stderr, "Unknown host %s\n", host);
		return 0;
	}

	/* create socket */
	sock = socket (AF_INET, SOCK_STREAM, 0);
	if (sock < 0) {
		perror ("Can't create socket: ");
		return 0;
	}


	/* build address from host addr, asking port number to super-server */
	memcpy (&addr.sin_addr, hp->h_addr, hp->h_length);
	addr.sin_family = AF_INET;
	addr.sin_port = GetPort (addr.sin_addr.s_addr);
	if (! addr.sin_port)
		return 0;

	/* connect socket on address */
	if (connect (sock, &addr, sizeof (addr)) < 0) {
		perror ("Can't connect socket: ");
		return 0;
	}

	return sock;
}


int
SendMsg (int sock, const char* s)
{
	request req;

	/* build request */
	strcpy (req.buffer, s);

	/* send request */
	/* we should handle return value more finely */
	if (write (sock, &req, sizeof (request)) != sizeof (request)) {
		fprintf (stderr, "Unable to write %d bytes: ", sizeof (request));
		perror ("");
	} 

#if 0
	answer ans;
	register char *p = (char *) &ans;
	register int n, l;

	/* retrieve answer (useless) */
	for (n = sizeof (answer); n > 0; p += l) {
		n -= (l = read (sock, p, n));
		if (l <= 0) {
			perror ("Error retrieving answer from server: ");
			return 0;
		}
	}
	return ans.ok;
#endif
	return 1;
}

void
HandleArgs (int sock, int index, int argc, char** argv)
{
	char buf [BUFSIZE];
	int space = 0;
	int nbchars = 0;

	/* slice arguments into buffer */
	buf [0] = '\0';
	while (index < argc) {
		const char* p = argv[index++];
		int l = strlen (p);
		/* while we have pending chars for this arg... */
		while (l + space > 0) {
			/* first try and fit space if needed */
			if (space) {
				if (nbchars + space <= BUFSIZE - 1) {
					strcat (buf, " ");
					nbchars += space;
					space = 0;
				} else {
					goto bufferfull;
				}
			}

			/* then look if we can fit all the chars we have */
			if (nbchars + l <= BUFSIZE - 1) {
				/* if yes, go ahead */
				strcat (buf, p);
				nbchars += l;
				/* we'll need to insert space if there are other args */
				space = 1;
				/* but let's make sure we don't keep looping */
				l = -1;
				/* if buffer is full, handle it */
				if (nbchars == BUFSIZE - 1)
					goto bufferfull;
				/* otherwise, we're done anyway */
				else
					continue;

			/* if not enough room, first fit what we can */
			} else {
				int fitting = (BUFSIZE - 1) - nbchars;
				if (fitting > 0) {
					strncat (buf, p, fitting);
					nbchars += fitting;
					l -= fitting;
					p += fitting;
				}
			}


bufferfull:			/* now we have a full buffer */
			/* send it */
			if (debug)
				printf ("Sending [%s]\n", buf);
			SendMsg (sock, buf);
			/* and prepare for next round */
			nbchars = 0;
			buf [0] = '\0';
		}
	}
	if (nbchars > 0) {
		if (debug)
			printf ("Sending [%s]\n", buf);
		SendMsg (sock, buf);
	}
}


/*
 * Demande un numero de port au super-serveur de la machine addr
 */


int
main (int argc, char** argv)
{
	char busbuf [128];
	const char* bus = 0;
	char serverhostbuf [128];
	const char* serverhost = 0;
	const struct option options [] = {
		{"bus", required_argument, 0, 'b'},
		{"debug", no_argument, 0, 'd'},
		{"server", required_argument, 0, 's'},
		{0, 0, 0, 0}
	};
	char c;
	int servfd;

#if 0
	if (strlen (argv0) >= 4 && !strcmp (argv0+strlen (argv0)-4, "wait"))
		wflag = 1;
#endif

	/* handle options */
	while ((c = getopt_long (argc, argv, "+b:s:d", options, 0)) != EOF) {
		switch (c) {
		case 'b':
			strcpy (busbuf, optarg) ;
			bus = busbuf;
			break;
		case 's':
			strcpy (serverhostbuf, optarg) ;
			serverhost = serverhostbuf;
			break;
		case 'd':
			debug = 1;
			break;
		}
	}


	/* Se connecter au serveur.  */
	servfd = ServerOpen (serverhost);
	if (!servfd) {
		fprintf (stderr, "No server.\n");
		return 0;
	}

	HandleArgs (servfd, optind, argc, argv);

	return 1;
}