/*
     This file is part of GNUnet.
     (C) 2011 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, 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
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file ats/gnunet-service-ats_scheduling.c
 * @brief ats service, interaction with 'scheduling' API
 * @author Matthias Wachs
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet-service-ats.h"
#include "gnunet-service-ats_addresses.h"
#include "gnunet-service-ats_scheduling.h"
#include "ats.h"


/**
 * Context for sending messages to clients.
 */
static struct GNUNET_SERVER_NotificationContext *nc;

/**
 * Actual handle to the client.
 */
static struct GNUNET_SERVER_Client *my_client;


/**
 * Register a new scheduling client.
 *
 * @param client handle of the new client
 * @return GNUNET_OK on success, GNUNET_SYSERR on error
 */
int
GAS_scheduling_add_client (struct GNUNET_SERVER_Client *client)
{
  if (my_client != NULL)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "This ATS already has a scheduling client, refusing new scheduling client for now.\n");
    return GNUNET_SYSERR;
  }
  my_client = client;
  GNUNET_SERVER_notification_context_add (nc, client);
  GNUNET_SERVER_client_keep (client);
  return GNUNET_OK;
}


/**
 * Unregister a client (which may have been a scheduling client,
 * but this is not assured).
 *
 * @param client handle of the (now dead) client
 */
void
GAS_scheduling_remove_client (struct GNUNET_SERVER_Client *client)
{
  if (my_client != client)
    return;
  GAS_addresses_destroy_all ();
  GNUNET_SERVER_client_drop (client);
  my_client = NULL;
}


/**
 * Transmit the given address suggestion and bandwidth update to all scheduling
 * clients.
 *
 * @param peer peer for which this is an address suggestion
 * @param plugin_name 0-termintated string specifying the transport plugin
 * @param plugin_addr binary address for the plugin to use
 * @param plugin_addr_len number of bytes in plugin_addr
 * @param session_id session ID to use for the given client (other clients will see 0)
 * @param atsi performance data for the address
 * @param atsi_count number of performance records in 'ats'
 * @param bandwidth_out assigned outbound bandwidth
 * @param bandwidth_in assigned inbound bandwidth
 */
void
GAS_scheduling_transmit_address_suggestion (const struct GNUNET_PeerIdentity
                                            *peer, const char *plugin_name,
                                            const void *plugin_addr,
                                            size_t plugin_addr_len,
                                            uint32_t session_id,
                                            const struct GNUNET_ATS_Information
                                            *atsi, uint32_t atsi_count,
                                            struct GNUNET_BANDWIDTH_Value32NBO
                                            bandwidth_out,
                                            struct GNUNET_BANDWIDTH_Value32NBO
                                            bandwidth_in)
{
  struct AddressSuggestionMessage *msg;
  size_t plugin_name_length = strlen (plugin_name) + 1;
  size_t msize =
      sizeof (struct AddressSuggestionMessage) +
      atsi_count * sizeof (struct GNUNET_ATS_Information) + plugin_addr_len +
      plugin_name_length;
  char buf[msize];
  struct GNUNET_ATS_Information *atsp;
  char *addrp;

  if (my_client == NULL)
    return;
  GNUNET_STATISTICS_update (GSA_stats, "# address suggestions made", 1,
                            GNUNET_NO);
  GNUNET_assert (msize < GNUNET_SERVER_MAX_MESSAGE_SIZE);
  GNUNET_assert (atsi_count <
                 GNUNET_SERVER_MAX_MESSAGE_SIZE /
                 sizeof (struct GNUNET_ATS_Information));
  msg = (struct AddressSuggestionMessage *) buf;
  msg->header.size = htons (msize);
  msg->header.type = htons (GNUNET_MESSAGE_TYPE_ATS_ADDRESS_SUGGESTION);
  msg->ats_count = htonl (atsi_count);
  msg->peer = *peer;
  msg->address_length = htons (plugin_addr_len);
  msg->plugin_name_length = htons (plugin_name_length);
  msg->session_id = htonl (session_id);
  msg->bandwidth_out = bandwidth_out;
  msg->bandwidth_in = bandwidth_in;
  atsp = (struct GNUNET_ATS_Information *) &msg[1];
  memcpy (atsp, atsi, sizeof (struct GNUNET_ATS_Information) * atsi_count);
  addrp = (char *) &atsp[atsi_count];
  memcpy (addrp, plugin_addr, plugin_addr_len);
  strcpy (&addrp[plugin_addr_len], plugin_name);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "ATS sends quota for peer `%s': (in/out) %u/%u\n",
              GNUNET_i2s (peer), ntohl (bandwidth_in.value__),
              ntohl (bandwidth_out.value__));

  GNUNET_SERVER_notification_context_unicast (nc, my_client, &msg->header,
                                              GNUNET_YES);
}


/**
 * Handle 'request address' messages from clients.
 *
 * @param cls unused, NULL
 * @param client client that sent the request
 * @param message the request message
 */
void
GAS_handle_request_address (void *cls, struct GNUNET_SERVER_Client *client,
                            const struct GNUNET_MessageHeader *message)
{
  const struct RequestAddressMessage *msg =
      (const struct RequestAddressMessage *) message;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received `%s' message\n",
              "REQUEST_ADDRESS");
  GNUNET_STATISTICS_update (GSA_stats, "# address requests received", 1,
                            GNUNET_NO);
  GNUNET_break (0 == ntohl (msg->reserved));
  GAS_addresses_request_address (&msg->peer);
  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}


/**
 * Handle 'request address' messages from clients.
 *
 * @param cls unused, NULL
 * @param client client that sent the request
 * @param message the request message
 */
void
GAS_handle_request_address_cancel (void *cls,
                                   struct GNUNET_SERVER_Client *client,
                                   const struct GNUNET_MessageHeader *message)
{
  const struct RequestAddressMessage *msg =
      (const struct RequestAddressMessage *) message;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received `%s' message\n",
              "REQUEST_ADDRESS_CANCEL");
  GNUNET_break (0 == ntohl (msg->reserved));

  /* TODO */

  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}


/**
 * Handle 'address update' messages from clients.
 *
 * @param cls unused, NULL
 * @param client client that sent the request
 * @param message the request message
 */
void
GAS_handle_address_update (void *cls, struct GNUNET_SERVER_Client *client,
                           const struct GNUNET_MessageHeader *message)
{
  const struct AddressUpdateMessage *m;
  const struct GNUNET_ATS_Information *atsi;
  const char *address;
  const char *plugin_name;
  uint16_t address_length;
  uint16_t plugin_name_length;
  uint32_t ats_count;
  uint16_t size;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received `%s' message\n",
              "ADDRESS_UPDATE");
  size = ntohs (message->size);
  if (size < sizeof (struct AddressUpdateMessage))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }
  m = (const struct AddressUpdateMessage *) message;
  ats_count = ntohl (m->ats_count);
  address_length = ntohs (m->address_length);
  plugin_name_length = ntohs (m->plugin_name_length);
  atsi = (const struct GNUNET_ATS_Information *) &m[1];
  address = (const char *) &atsi[ats_count];
  if (plugin_name_length != 0)
    plugin_name = &address[address_length];
  else
    plugin_name = "";
  if ((address_length + plugin_name_length +
       ats_count * sizeof (struct GNUNET_ATS_Information) +
       sizeof (struct AddressUpdateMessage) != ntohs (message->size)) ||
      (ats_count >
       GNUNET_SERVER_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_ATS_Information))
      || (plugin_name[plugin_name_length - 1] != '\0'))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }
  GNUNET_STATISTICS_update (GSA_stats, "# address updates received", 1,
                            GNUNET_NO);
  GAS_addresses_update (&m->peer, plugin_name, address, address_length,
                        ntohl (m->session_id), atsi, ats_count);
  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}


/**
 * Handle 'address in use' messages from clients.
 *
 * @param cls unused, NULL
 * @param client client that sent the request
 * @param message the request message
 */
void
GAS_handle_address_in_use (void *cls, struct GNUNET_SERVER_Client *client,
                           const struct GNUNET_MessageHeader *message)
{
  const struct AddressUseMessage *m;
  const char *address;
  const char *plugin_name;
  uint16_t address_length;
  uint16_t plugin_name_length;

  uint16_t size;
  uint16_t in_use;

  size = ntohs (message->size);
  if (size < sizeof (struct AddressUseMessage))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }
  m = (const struct AddressUseMessage *) message;

  address_length = ntohs (m->address_length);
  plugin_name_length = ntohs (m->plugin_name_length);

  address = (const char *) &m[1];
  if (plugin_name_length != 0)
    plugin_name = &address[address_length];
  else
    plugin_name = "";

  if ((address_length + plugin_name_length +
       sizeof (struct AddressUseMessage) != ntohs (message->size)) ||
      (plugin_name[plugin_name_length - 1] != '\0'))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }

  in_use = ntohs (m->in_use);
  GAS_addresses_in_use (&m->peer, plugin_name, address, address_length,
                        ntohl (m->session_id), in_use);

  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}

/**
 * Handle 'address destroyed' messages from clients.
 *
 * @param cls unused, NULL
 * @param client client that sent the request
 * @param message the request message
 */
void
GAS_handle_address_destroyed (void *cls, struct GNUNET_SERVER_Client *client,
                              const struct GNUNET_MessageHeader *message)
{
  const struct AddressDestroyedMessage *m;
  struct SessionReleaseMessage srm;
  const char *address;
  const char *plugin_name;
  uint16_t address_length;
  uint16_t plugin_name_length;
  uint16_t size;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received `%s' message of size %u %u\n",
              "ADDRESS_DESTROYED", ntohs (message->size),
              sizeof (struct AddressDestroyedMessage));
  size = ntohs (message->size);
  if ((size < sizeof (struct AddressDestroyedMessage)) || (client != my_client))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }
  m = (const struct AddressDestroyedMessage *) message;
  GNUNET_break (0 == ntohl (m->reserved));
  address_length = ntohs (m->address_length);
  plugin_name_length = ntohs (m->plugin_name_length);
  address = (const char *) &m[1];
  if (plugin_name_length != 0)
    plugin_name = &address[address_length];
  else
    plugin_name = "";
  if ((address_length + plugin_name_length +
       sizeof (struct AddressDestroyedMessage) != ntohs (message->size)))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }
  if ((plugin_name_length == 0) ||
      (plugin_name[plugin_name_length - 1] != '\0'))
  {
    GNUNET_break (0);
    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
    return;
  }
  GNUNET_STATISTICS_update (GSA_stats, "# addresses destroyed", 1, GNUNET_NO);
  GAS_addresses_destroy (&m->peer, plugin_name, address, address_length,
                         ntohl (m->session_id));
  if (0 != ntohl (m->session_id))
  {
    srm.header.type = ntohs (GNUNET_MESSAGE_TYPE_ATS_SESSION_RELEASE);
    srm.header.size = ntohs (sizeof (struct SessionReleaseMessage));
    srm.session_id = m->session_id;
    srm.peer = m->peer;
    GNUNET_SERVER_notification_context_unicast (nc, client, &srm.header,
                                                GNUNET_NO);
  }
  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}


/**
 * Initialize scheduling subsystem.
 *
 * @param server handle to our server
 */
void
GAS_scheduling_init (struct GNUNET_SERVER_Handle *server)
{
  nc = GNUNET_SERVER_notification_context_create (server, 128);
}


/**
 * Shutdown scheduling subsystem.
 */
void
GAS_scheduling_done ()
{
  GNUNET_SERVER_notification_context_destroy (nc);
  nc = NULL;
}


/* end of gnunet-service-ats_scheduling.c */