/*
 * Secure X Message Passing Library v2 examples.
 *
 * (c) Originally written by somebody else ...
 * (c) Alexander Vdolainen 2013-2015 <avdolainen@gmail.com>
 *
 * libsxmp is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libsxmp 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.";
 *
 */

/*
 * This is an example of sxmp usage.
 * NOTE: It was developed quite fast within one day,
 * btw - this the reason of some ugly code here.
 *
 * This is a master or simply - daemon part, it will
 * listen a requests and create a stream with directory entries,
 * which ridden by the client.
 * Using the builtin stream functionality added since 0.4.2 version.
 *
 * This implements a simple client-server topology, to see
 * more advanced technics check out other examples.
 *
 * NOTE(win32): don't have a time to test it or fix it to
 * make it works on windows, if you can - u're welcome.
 */

#include <stdio.h>
#include <dirent.h>
#define __USE_GNU
#include <stdlib.h>
#include <stdarg.h>
#include <sys/types.h>
#include <limits.h>
#include <sys/select.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/resource.h>
#include <netdb.h>
#include <unistd.h>
#include <uuid/uuid.h>
#include <execinfo.h>
#include <netinet/in.h>

#include <tdata/usrtc.h>
#include <sexpr/sexp.h>
#include <sxmp/limits.h>
#include <sxmp/sxmp.h>

#include <pthread.h>
#include <stdint.h>
#include <getopt.h>
#include <errno.h>

#include "filelist.h"
#include "helpers.h"
#include "../config.h"

#define FULL_PROGRAM_NAME        "File lister master (builtin streams based)"

/* firstly we need to take an rpc calls data,
 * sxmp uses usrtc from libtdata to store it
 */
static usrtc_t *fulist;

/* ok, here we will define out sxmp specific functions */

/*
 * RPC list contain groups of RPC calls called channel types
 * for each sxmp link depends on access rules you can change
 * available channel types.
 * To do so you must provide a special callback returning this list.
 * Since we haven't any access restrictions in our example, just
 * create a fake.
 */
static usrtc_t *__rettlist(sxlink_t *l)
{
  return fulist;
}

/*
 * Each sxmp link validated by certificate ID,
 * i.e. when basic checking is done, you can also
 * review the certificate ID, for example you need
 * to disable certificate for a time being.
 *
 * Here we don't have those checks, just always accept
 */
static int __validate_sslpem(sxlink_t *l)
{
  return 0;
}

/*
 * To be more paranoic, sxmp also allow to
 * check up username and password.
 * We don't overview this tuff here, just
 * always allow.
 */
static int __secure_check(sxlink_t *l)
{
  return SXE_SUCCESS;
}

/* misc functions */
static int __ping(void *m, sexp_t *sx)
{
  return sxmsg_return((sxmsg_t*)m, SXE_SUCCESS);
}

/* command line options helpers */
static void __help_print(FILE *fso, const char *fmtname)
{
  fprintf(fso, "\n%s\n\n", FULL_PROGRAM_NAME);

  /* usage options */
  fprintf(fso, "Usage:\n");
  fprintf(fso, "\t%s -r | --root-x509 <path> -u | --master-x509 <path> "
          " [-p | --listen-port <port>]\n", fmtname);

  /* defaults */
  fprintf(fso, "\t%s -h | --help\n", fmtname);
  fprintf(fso, "\t%s -v | --version\n", fmtname);

  /* options description */
  fprintf(fso, "\nOptions:\n");
  fprintf(fso, "\t%-33s Set pathname of the remote root X.509 public certificate.\n",
          "-r | --root-x509 <path>");
  fprintf(fso, "\t%-33s Set pathname of the host X.509 public and private certificate.\n",
          "-m | --master-x509 <path>");
  fprintf(fso, "\t%-33s Remote host listening port number [default: %d].\n",
          "-p | --listen-port <port>", DEFAULT_PORT);
  fprintf(fso, "\t%-33s Show help screen.\n", "-h | --help");
  fprintf(fso, "\t%-33s Print version information.\n", "-v | --version");
  return;
}

static void __version_print(FILE *fso)
{
  fprintf(fso, "\nFile list example master daemon (builtin streams).\n");
  fprintf(fso, "Examples bundle for %s %s.\n", PACKAGE_NAME, PACKAGE_VERSION);
  return;
}

int main(int argc, char **argv)
{
  char *rootca = NULL, *cert = NULL;
  sxhub_t *sxmphub = sxhub_create();
  int port = DEFAULT_PORT;
  int opt;

  while(1) {
    int option_index = 0;
    static struct option long_options[] = {
      /* These options a generic ones. */
      {"help", no_argument, NULL, 'h'}, /* print out help and version info */
      {"version", no_argument, NULL, 'v'}, /* just out a version info */
      /*  The following options about settings . */
      {"root-x509", required_argument, NULL, 'r'},
      {"master-x509", required_argument, NULL, 'm'},
      {"listen-port", required_argument, NULL, 'p'},
      { NULL, 0, NULL, 0 },
    };

    if((opt = getopt_long(argc, argv, "hvr:m:", long_options,
                          &option_index)) == -1) break;

    switch(opt) {
    case 'h':
      __help_print(stdout, argv[0]);
      return 0;
      break;
    case 'v':
      __version_print(stdout);
      return 0;
      break;
    case 'r':
      if(!(rootca = strdup(optarg))) return ENOMEM;
      break;
    case 'm':
      if(!(cert = strdup(optarg))) return ENOMEM;
      break;
    case 'p':
      port = atoi(optarg);
      break;
    }
  }

  if(!rootca) {
    fprintf(stderr, "Root CA not pointed.\n Failure.\n");
    __help_print(stderr, argv[0]);
    return EINVAL;
  }

  if(!cert) {
    fprintf(stderr, "User certificate not pointed.\n Failure.\n");
    __help_print(stderr, argv[0]);
    return EINVAL;
  }

  sxmp_init();

  /* all is fine let's init connection subsystem */
  if(!sxmphub) {
    fprintf(stderr, "Subsystem init failed: %d\n", opt);
    return 2;
  }
  /* set working certificates */
  opt = sxhub_setsslserts(sxmphub, rootca, cert, cert);
  if(opt) {
    fprintf(stderr, "Subsystem init failed (set SSL x.509 pems): %d\n", opt);
    return opt;
  }

  /* clean up */
  free(rootca);
  free(cert);

  /* set important callbacks to do the security checking */
  sxhub_set_authcheck(sxmphub, __secure_check);
  sxhub_set_sslvalidate(sxmphub, __validate_sslpem);

  /* ok, now we need to construct RPC lists (channels) */
  if(!(fulist = malloc(sizeof(usrtc_t)))) {
    fprintf(stderr, "Cannot allocate memory for RPC lists\n Failure.\n");
    return ENOMEM;
  }
  opt = sxmp_rpclist_init(fulist);
  if(opt) {
    fprintf(stderr, "Failed to init rpc list\n Failure.\n");
    return opt;
  }

  /* we will add one channel with type id READONLY_CHANNEL for read only operations */
  opt = sxmp_rpclist_add(fulist, READONLY_CHANNEL, "Read only operations", NULL);
  if(opt) {
    fprintf(stderr, "Failed to add typed RPC channel\n Failure.\n");
    return opt;
  }

  /* ok, let's add stream functions */
  opt = sxmp_rpclist_add_function(fulist, READONLY_CHANNEL, "ping", __ping);
  if(opt) {
  __fail:
    fprintf(stderr, "Failed to add functions to typed RPC channel\n Failure.\n");
    return opt;
  }

  /* ok, setup it */
  sxhub_set_rpcvalidator(sxmphub, __rettlist);

  signal(SIGPIPE, SIG_IGN);

  /* now we're ready to run the listen process */
  int srv = openlistener_socket(port);

  while(1) {
    struct sockaddr_in addr;
    socklen_t len = sizeof(addr);
    sxlink_t *link;

    int client = accept(srv, (struct sockaddr*)&addr, &len); /* accept connection as usual */

    link = sxlink_master_accept(sxmphub, client, NULL);

    if(!link) fprintf(stderr, "Cannot create sxmp link (%d)\n", errno);
  }

  sxhub_destroy(sxmphub);

  sxmp_finalize();

  return 0;
}