/** Test client for the distributed mutual exclusion algorithm
 * @author Marko Mäkelä (Marko.Makela@HUT.FI)
 */

#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/time.h>
#include<sys/types.h>
#include<sys/select.h>
#include<netinet/in.h>
#include<netdb.h>

#ifndef MSG_NOSIGNAL
# define MSG_NOSIGNAL 0
#endif

/** Messages originated by the client */
enum client_msg { res_req, rel_req };
/** Messages originated by the server */
enum server_msg { res_rej, res_ack, rel_ack };

int
main (int argc, char** argv)
{
  /** the datagram socket */
  int s;
  /** the address of the server */
  static struct sockaddr_in addr;
  /** file descriptor set for select(2) */
  static fd_set fds;
  /** timeout for select(2) */
  static struct timeval tv;

  if (argc != 3) {
    fputs ("usage: client serveraddress portnumber\n", stderr);
    return 1;
  }
  else {
    const struct hostent* h;
    char* endp;
    unsigned long port = strtoul (argv[2], &endp, 0);
    if (!argv[2] || *endp || port > 65535) {
      fputs ("invalid remote port number \"", stderr);
      fputs (argv[2], stderr);
      fputs ("\"\n", stderr);
      return 1;
    }

    if (!(h = gethostbyname (argv[1]))) {
      fputs ("gethostbyname: ", stderr);
      fputs (argv[1], stderr);
      fputs (": ", stderr);
      switch (h_errno) {
      case HOST_NOT_FOUND:
	fputs ("host not found\n", stderr);
	break;
      case NO_ADDRESS:
	fputs ("no address\n", stderr);
	break;
      case NO_RECOVERY:
	fputs ("non-recoverable error\n", stderr);
	break;
      case TRY_AGAIN:
	fputs ("try again later\n", stderr);
	break;
      default:
	fprintf (stderr, "unknown error %d\n", h_errno);
	break;
      }
      return 2;
    }
    if (h->h_addrtype != AF_INET ||
	h->h_length != sizeof addr.sin_addr) {
      fputs ("gethostbyname ", stderr);
      fputs (argv[1], stderr);
      fputs (": not an IPv4 address\n", stderr);
      return 2;
    }
    else
      memcpy (&addr.sin_addr, h->h_addr, sizeof addr.sin_addr);

    s = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (s < 0) {
      perror ("socket");
      return 2;
    }

    addr.sin_family = AF_INET;
    addr.sin_port = htons (port);

    if (connect (s, (const struct sockaddr*) &addr, sizeof addr)) {
      perror ("connect");
      return 2;
    }
  }

  fputs ("press 1 to send res_req, 2 for rel_req, EOF to quit\n", stderr);

  for (;;) {
    int i;
    char c;
    i = getchar ();
    switch (i) {
    case EOF:
      return 0;
    default:
      fputs ("unknown command '", stderr);
      fputc (i, stderr);
      fputs ("'\n", stderr);
    case '\r':
    case '\n':
      continue;
    case '1':
      c = res_req;
      break;
    case '2':
      c = rel_req;
      break;
    }

    fputs ("sending...", stderr);
    fflush (stderr);
    if (1 != send (s, &c, 1, MSG_NOSIGNAL)) {
      perror ("\nsend");
      return 2;
    }
    FD_ZERO (&fds);
    FD_SET (s, &fds);
    tv.tv_sec = 1, tv.tv_usec = 0;
    i = select (s + 1, &fds, 0, 0, &tv);
    if (i < 0) {
      perror ("\nselect");
      return 2;
    }
    else if (i != 1) {
      fputs ("timeout\n", stderr);
      continue;
    }
    i = recv (s, &c, 1, MSG_TRUNC | MSG_NOSIGNAL);
    if (i < 0) {
      perror ("\nrecv");
      return 2;
    }
    fputs ("acknowledged\n", stderr);
    if (i != 1)
      fputs ("unexcepted reply packet\n", stderr);
    else {
      switch (c) {
      default:
	fputs ("unexpected reply PDU\n", stderr);
	break;
      case res_rej:
	fputs ("got res_rej\n", stderr);
	break;
      case res_ack:
	fputs ("got res_ack\n", stderr);
	break;
      case rel_ack:
	fputs ("got rel_ack\n", stderr);
	break;
      }
    }
  }
}