/*
     This file is part of GNUnet.
     Copyright (C) 2001-2014, 2016 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @file peerinfo-tool/gnunet-peerinfo.c
 * @brief Print information about other known peers.
 * @author Christian Grothoff
 * @author Matthias Wachs
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_hello_lib.h"
#include "gnunet_transport_service.h"
#include "gnunet_transport_hello_service.h"
#include "gnunet_peerinfo_service.h"
#include "gnunet-peerinfo_plugins.h"

/**
 * How long until we time out during address lookup?
 */
#define TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)

/**
 * Structure we use to collect printable address information.
 */
struct PrintContext;

/**
 * Record we keep for each printable address.
 */
struct AddressRecord
{
  /**
   * Current address-to-string context (if active, otherwise NULL).
   */
  struct GNUNET_TRANSPORT_AddressToStringContext *atsc;

  /**
   * Address expiration time
   */
  struct GNUNET_TIME_Absolute expiration;

  /**
   * Printable address.
   */
  char *result;

  /**
   * Print context this address record belongs to.
   */
  struct PrintContext *pc;
};


/**
 * Structure we use to collect printable address information.
 */
struct PrintContext
{
  /**
   * Kept in DLL.
   */
  struct PrintContext *next;

  /**
   * Kept in DLL.
   */
  struct PrintContext *prev;

  /**
   * Identity of the peer.
   */
  struct GNUNET_PeerIdentity peer;

  /**
   * List of printable addresses.
   */
  struct AddressRecord *address_list;

  /**
   * Number of completed addresses in @e address_list.
   */
  unsigned int num_addresses;

  /**
   * Number of addresses allocated in @e address_list.
   */
  unsigned int address_list_size;

  /**
   * Current offset in @e address_list (counted down).
   */
  unsigned int off;

  /**
   * Hello was friend only, #GNUNET_YES or #GNUNET_NO
   */
  int friend_only;
};


/**
 * Option '-n'
 */
static int no_resolve;

/**
 * Option '-q'
 */
static int be_quiet;

/**
 * Option '-f'
 */
static int include_friend_only;

/**
 * Option '-s'
 */
static int get_self;

/**
 * Option
 */
static int get_uri;

/**
 * Option
 */
static int default_operation;

/**
 * Option '-i'
 */
static int get_info;

/**
 * Option
 */
static char *put_uri;

/**
 * Option -d
 */
static char *dump_hello;

/**
 * Handle to peerinfo service.
 */
static struct GNUNET_PEERINFO_Handle *peerinfo;

/**
 * Configuration handle.
 */
static const struct GNUNET_CONFIGURATION_Handle *cfg;

/**
 * Main state machine task (if active).
 */
static struct GNUNET_SCHEDULER_Task *tt;

/**
 * Pending #GNUNET_TRANSPORT_hello_get() operation.
 */
static struct GNUNET_TRANSPORT_HelloGetHandle *gh;

/**
 * Current iterator context (if active, otherwise NULL).
 */
static struct GNUNET_PEERINFO_IteratorContext *pic;

/**
 * My peer identity.
 */
static struct GNUNET_PeerIdentity my_peer_identity;

/**
 * Head of list of print contexts.
 */
static struct PrintContext *pc_head;

/**
 * Tail of list of print contexts.
 */
static struct PrintContext *pc_tail;

/**
 * Handle to current #GNUNET_PEERINFO_add_peer() operation.
 */
static struct GNUNET_MQ_Envelope *ac;

/**
 * Hello of this peer (if initialized).
 */
static struct GNUNET_HELLO_Message *my_hello;


/**
 * Main state machine that goes over all options and
 * runs the next requested function.
 *
 * @param cls unused
 */
static void
state_machine (void *cls);


/* ********************* 'get_info' ******************* */

/**
 * Print the collected address information to the console and free @a pc.
 *
 * @param pc printing context
 */
static void
dump_pc (struct PrintContext *pc)
{
  unsigned int i;

  printf (_ ("%sPeer `%s'\n"),
          (GNUNET_YES == pc->friend_only) ? "F2F: " : "",
          GNUNET_i2s_full (&pc->peer));
  for (i = 0; i < pc->num_addresses; i++)
  {
    if (NULL != pc->address_list[i].result)
    {
      printf (_ ("\tExpires: %s \t %s\n"),
              GNUNET_STRINGS_absolute_time_to_string (
                pc->address_list[i].expiration),
              pc->address_list[i].result);
      GNUNET_free (pc->address_list[i].result);
    }
  }
  printf ("\n");
  GNUNET_free_non_null (pc->address_list);
  GNUNET_CONTAINER_DLL_remove (pc_head, pc_tail, pc);
  GNUNET_free (pc);
  if ((NULL == pc_head) && (NULL == pic))
    tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
}


/* ************************* list all known addresses **************** */


/**
 * Function to call with a human-readable format of an address
 *
 * @param cls closure
 * @param address NULL on error, otherwise 0-terminated printable UTF-8 string
 * @param res result of the address to string conversion:
 *        if #GNUNET_OK: address was valid (conversion to
 *                       string might still have failed)
 *        if #GNUNET_SYSERR: address is invalid
 */
static void
process_resolved_address (void *cls, const char *address, int res)
{
  struct AddressRecord *ar = cls;
  struct PrintContext *pc = ar->pc;

  if (NULL != address)
  {
    if (0 != strlen (address))
    {
      if (NULL != ar->result)
        GNUNET_free (ar->result);
      ar->result = GNUNET_strdup (address);
    }
    return;
  }
  ar->atsc = NULL;
  if (GNUNET_SYSERR == res)
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                _ ("Failure: Cannot convert address to string for peer `%s'\n"),
                GNUNET_i2s (&ar->pc->peer));
  pc->num_addresses++;
  if (pc->num_addresses == pc->address_list_size)
    dump_pc (pc);
}


/**
 * Iterator callback to go over all addresses and count them.
 *
 * @param cls `struct PrintContext *` with `off` to increment
 * @param address the address
 * @param expiration expiration time
 * @return #GNUNET_OK to keep the address and continue
 */
static int
count_address (void *cls,
               const struct GNUNET_HELLO_Address *address,
               struct GNUNET_TIME_Absolute expiration)
{
  struct PrintContext *pc = cls;

  pc->off++;
  return GNUNET_OK;
}


/**
 * Iterator callback to go over all addresses.
 *
 * @param cls closure
 * @param address the address
 * @param expiration expiration time
 * @return #GNUNET_OK to keep the address and continue
 */
static int
print_address (void *cls,
               const struct GNUNET_HELLO_Address *address,
               struct GNUNET_TIME_Absolute expiration)
{
  struct PrintContext *pc = cls;
  struct AddressRecord *ar;

  GNUNET_assert (0 < pc->off);
  ar = &pc->address_list[--pc->off];
  ar->pc = pc;
  ar->expiration = expiration;
  GNUNET_asprintf (&ar->result,
                   "%s:%u:%u",
                   address->transport_name,
                   address->address_length,
                   address->local_info);
  ar->atsc = GNUNET_TRANSPORT_address_to_string (cfg,
                                                 address,
                                                 no_resolve,
                                                 TIMEOUT,
                                                 &process_resolved_address,
                                                 ar);
  return GNUNET_OK;
}


/**
 * Print information about the peer.  Currently prints the `struct
 * GNUNET_PeerIdentity` and the transport address.
 *
 * @param cls the `struct PrintContext *`
 * @param peer identity of the peer
 * @param hello addresses of the peer
 * @param err_msg error message
 */
static void
print_peer_info (void *cls,
                 const struct GNUNET_PeerIdentity *peer,
                 const struct GNUNET_HELLO_Message *hello,
                 const char *err_msg)
{
  struct PrintContext *pc;
  int friend_only;

  if (NULL == peer)
  {
    pic = NULL;   /* end of iteration */
    if (NULL != err_msg)
    {
      fprintf (stderr,
               _ ("Error in communication with PEERINFO service: %s\n"),
               err_msg);
    }
    if (NULL == pc_head)
      tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
    return;
  }
  friend_only = GNUNET_NO;
  if (NULL != hello)
    friend_only = GNUNET_HELLO_is_friend_only (hello);
  if ((GNUNET_YES == be_quiet) || (NULL == hello))
  {
    printf ("%s%s\n",
            (GNUNET_YES == friend_only) ? "F2F: " : "",
            GNUNET_i2s_full (peer));
    return;
  }
  pc = GNUNET_new (struct PrintContext);
  GNUNET_CONTAINER_DLL_insert (pc_head, pc_tail, pc);
  pc->peer = *peer;
  pc->friend_only = friend_only;
  GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &count_address, pc);
  if (0 == pc->off)
  {
    dump_pc (pc);
    return;
  }
  pc->address_list_size = pc->off;
  pc->address_list = GNUNET_malloc (sizeof(struct AddressRecord) * pc->off);
  GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &print_address, pc);
}


/* ************************* DUMP Hello  ************************** */

/**
 * Count the number of addresses in the HELLO.
 *
 * @param cls pointer to an `int *` used for the counter
 * @param address an address to count
 * @param expiration (unused)
 * @return #GNUNET_OK
 */
static int
count_addr (void *cls,
            const struct GNUNET_HELLO_Address *address,
            struct GNUNET_TIME_Absolute expiration)
{
  int *c = cls;

  (*c)++;
  return GNUNET_OK;
}


/**
 * Write HELLO of my peer to a file.
 *
 * @param cls the `struct GetUriContext *`
 * @param peer identity of the peer (unused)
 * @param hello addresses of the peer
 * @param err_msg error message
 */
static void
dump_my_hello ()
{
  unsigned int size;
  unsigned int c_addr;

  size = GNUNET_HELLO_size (my_hello);
  if (0 == size)
  {
    fprintf (stderr, _ ("Failure: Received invalid %s\n"), "HELLO");
    return;
  }
  if (GNUNET_SYSERR == GNUNET_DISK_fn_write (dump_hello,
                                             my_hello,
                                             size,
                                             GNUNET_DISK_PERM_USER_READ
                                             | GNUNET_DISK_PERM_USER_WRITE
                                             | GNUNET_DISK_PERM_GROUP_READ
                                             | GNUNET_DISK_PERM_OTHER_READ))
  {
    fprintf (stderr,
             _ ("Failed to write HELLO with %u bytes to file `%s'\n"),
             size,
             dump_hello);
    if (0 != unlink (dump_hello))
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING
                                | GNUNET_ERROR_TYPE_BULK,
                                "unlink",
                                dump_hello);
  }
  c_addr = 0;
  GNUNET_HELLO_iterate_addresses (my_hello, GNUNET_NO, count_addr, &c_addr);

  if (! be_quiet)
  {
    fprintf (
      stderr,
      _ ("Wrote %s HELLO containing %u addresses with %u bytes to file `%s'\n"),
      (GNUNET_YES == GNUNET_HELLO_is_friend_only (my_hello)) ? "friend-only"
      : "public",
      c_addr,
      size,
      dump_hello);
  }
  GNUNET_free (dump_hello);
  dump_hello = NULL;
}


/* ************************* GET URI ************************** */


/**
 * Print URI of the peer.
 *
 * @param cls the `struct GetUriContext *`
 * @param peer identity of the peer (unused)
 * @param hello addresses of the peer
 * @param err_msg error message
 */
static void
print_my_uri (void *cls,
              const struct GNUNET_PeerIdentity *peer,
              const struct GNUNET_HELLO_Message *hello,
              const char *err_msg)
{
  char *uri;

  if (NULL == peer)
  {
    pic = NULL;
    if (NULL != err_msg)
      fprintf (stderr,
               _ ("Error in communication with PEERINFO service: %s\n"),
               err_msg);
    tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
    return;
  }

  if (NULL == hello)
    return;
  uri = GNUNET_HELLO_compose_uri (hello, &GPI_plugins_find);
  if (NULL != uri)
  {
    printf ("%s\n", (const char *) uri);
    GNUNET_free (uri);
  }
}


/* ************************* import HELLO by URI ********************* */


/**
 * Continuation called from #GNUNET_PEERINFO_add_peer()
 *
 * @param cls closure, NULL
 */
static void
add_continuation (void *cls)
{
  ac = NULL;
  tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
}


/**
 * Parse the PUT URI given at the command line and add it to our peerinfo
 * database.
 *
 * @param put_uri URI string to parse
 * @return #GNUNET_OK on success,
 *         #GNUNET_SYSERR if the URI was invalid,
 *         #GNUNET_NO on other errors
 */
static int
parse_hello_uri (const char *put_uri)
{
  struct GNUNET_HELLO_Message *hello = NULL;

  int ret = GNUNET_HELLO_parse_uri (put_uri,
                                    &my_peer_identity.public_key,
                                    &hello,
                                    &GPI_plugins_find);

  if (NULL != hello)
  {
    /* WARNING: this adds the address from URI WITHOUT verification! */
    if (GNUNET_OK == ret)
      ac = GNUNET_PEERINFO_add_peer (peerinfo, hello, &add_continuation, NULL);
    else
      tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
    GNUNET_free (hello);
  }
  return ret;
}


/* ************************ Main state machine ********************* */


/**
 * Main state machine that goes over all options and
 * runs the next requested function.
 *
 * @param cls unused
 */
static void
shutdown_task (void *cls)
{
  struct PrintContext *pc;
  struct AddressRecord *ar;
  unsigned int i;

  if (NULL != ac)
  {
    GNUNET_MQ_send_cancel (ac);
    ac = NULL;
  }
  if (NULL != tt)
  {
    GNUNET_SCHEDULER_cancel (tt);
    tt = NULL;
  }
  if (NULL != pic)
  {
    GNUNET_PEERINFO_iterate_cancel (pic);
    pic = NULL;
  }
  if (NULL != gh)
  {
    GNUNET_TRANSPORT_hello_get_cancel (gh);
    gh = NULL;
  }
  while (NULL != (pc = pc_head))
  {
    GNUNET_CONTAINER_DLL_remove (pc_head, pc_tail, pc);
    for (i = 0; i < pc->address_list_size; i++)
    {
      ar = &pc->address_list[i];
      GNUNET_free_non_null (ar->result);
      if (NULL != ar->atsc)
      {
        GNUNET_TRANSPORT_address_to_string_cancel (ar->atsc);
        ar->atsc = NULL;
      }
    }
    GNUNET_free_non_null (pc->address_list);
    GNUNET_free (pc);
  }
  GPI_plugins_unload ();
  if (NULL != peerinfo)
  {
    GNUNET_PEERINFO_disconnect (peerinfo);
    peerinfo = NULL;
  }
  if (NULL != my_hello)
  {
    GNUNET_free (my_hello);
    my_hello = NULL;
  }
}


/**
 * Function called with our peer's HELLO message.
 * Used to obtain our peer's public key.
 *
 * @param cls NULL
 * @param hello the HELLO message
 */
static void
hello_callback (void *cls, const struct GNUNET_MessageHeader *hello)
{
  if (NULL == hello)
  {
    fprintf (stderr, "Failed to get my own HELLO from this peer!\n");
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  my_hello = (struct GNUNET_HELLO_Message *) GNUNET_copy_message (hello);
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_HELLO_get_id (my_hello, &my_peer_identity));
  GNUNET_TRANSPORT_hello_get_cancel (gh);
  gh = NULL;
  if (NULL != dump_hello)
    dump_my_hello ();
  tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
}


/**
 * Main function that will be run by the scheduler.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param c configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *c)
{
  cfg = c;
  if ((NULL != args[0]) && (NULL == put_uri) &&
      (args[0] == strcasestr (args[0], "gnunet://hello/")))
  {
    put_uri = GNUNET_strdup (args[0]);
    args++;
  }
  if (NULL != args[0])
  {
    fprintf (stderr, _ ("Invalid command line argument `%s'\n"), args[0]);
    return;
  }
  if (NULL == (peerinfo = GNUNET_PEERINFO_connect (cfg)))
  {
    fprintf (stderr, "%s", "Could not access PEERINFO service.  Exiting.\n");
    return;
  }
  if ((GNUNET_YES == get_self) || (GNUNET_YES == get_uri) ||
      (NULL != dump_hello))
  {
    gh = GNUNET_TRANSPORT_hello_get (cfg,
                                     GNUNET_TRANSPORT_AC_ANY,
                                     &hello_callback,
                                     NULL);
  }
  else
  {
    tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
  }
  GNUNET_SCHEDULER_add_shutdown (&shutdown_task, NULL);
}


/**
 * Main state machine that goes over all options and
 * runs the next requested function.
 *
 * @param cls unused
 */
static void
state_machine (void *cls)
{
  tt = NULL;

  if (NULL != put_uri)
  {
    GPI_plugins_load (cfg);
    if (GNUNET_SYSERR == parse_hello_uri (put_uri))
    {
      fprintf (stderr, _ ("Invalid URI `%s'\n"), put_uri);
      GNUNET_SCHEDULER_shutdown ();
    }
    GNUNET_free (put_uri);
    put_uri = NULL;
  }
  else if (GNUNET_YES == get_info)
  {
    get_info = GNUNET_NO;
    GPI_plugins_load (cfg);
    pic = GNUNET_PEERINFO_iterate (peerinfo,
                                   include_friend_only,
                                   NULL,
                                   &print_peer_info,
                                   NULL);
  }
  else if (GNUNET_YES == get_self)
  {
    get_self = GNUNET_NO;
    if (be_quiet)
      printf ("%s\n", GNUNET_i2s_full (&my_peer_identity));
    else
      printf (_ ("I am peer `%s'.\n"), GNUNET_i2s_full (&my_peer_identity));
    tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
  }
  else if (GNUNET_YES == get_uri)
  {
    GPI_plugins_load (cfg);
    pic = GNUNET_PEERINFO_iterate (peerinfo,
                                   include_friend_only,
                                   &my_peer_identity,
                                   &print_my_uri,
                                   NULL);
    get_uri = GNUNET_NO;
  }
  else if (GNUNET_YES == default_operation)
  {
    /* default operation list all */
    default_operation = GNUNET_NO;
    get_info = GNUNET_YES;
    tt = GNUNET_SCHEDULER_add_now (&state_machine, NULL);
  }
  else
  {
    GNUNET_SCHEDULER_shutdown ();
  }
  default_operation = GNUNET_NO;
}


/**
 * The main function to obtain peer information.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc, char *const *argv)
{
  struct GNUNET_GETOPT_CommandLineOption options[] =
  { GNUNET_GETOPT_option_flag ('n',
                               "numeric",
                               gettext_noop ("don't resolve host names"),
                               &no_resolve),

    GNUNET_GETOPT_option_flag ('q',
                               "quiet",
                               gettext_noop (
                                 "output only the identity strings"),
                               &be_quiet),
    GNUNET_GETOPT_option_flag ('f',
                               "friends",
                               gettext_noop (
                                 "include friend-only information"),
                               &include_friend_only),

    GNUNET_GETOPT_option_flag ('s',
                               "self",
                               gettext_noop ("output our own identity only"),
                               &get_self),

    GNUNET_GETOPT_option_flag ('i',
                               "info",
                               gettext_noop ("list all known peers"),
                               &get_info),

    GNUNET_GETOPT_option_string ('d',
                                 "dump-hello",
                                 NULL,
                                 gettext_noop ("dump hello to file"),
                                 &dump_hello),

    GNUNET_GETOPT_option_flag ('g',
                               "get-hello",
                               gettext_noop ("also output HELLO uri(s)"),
                               &get_uri),

    GNUNET_GETOPT_option_string ('p',
                                 "put-hello",
                                 "HELLO",
                                 gettext_noop (
                                   "add given HELLO uri to the database"),
                                 &put_uri),

    GNUNET_GETOPT_OPTION_END };
  int ret;

  default_operation = GNUNET_YES;
  if (GNUNET_OK != GNUNET_STRINGS_get_utf8_args (argc, argv, &argc, &argv))
    return 2;

  ret = (GNUNET_OK ==
         GNUNET_PROGRAM_run (argc,
                             argv,
                             "gnunet-peerinfo",
                             gettext_noop ("Print information about peers."),
                             options,
                             &run,
                             NULL))
        ? 0
        : 1;
  GNUNET_free_nz ((void *) argv);
  return ret;
}


/* end of gnunet-peerinfo.c */