/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "DHTPeerAnnounceStorage.h"

#include <cstring>
#include <algorithm>

#include "DHTPeerAnnounceEntry.h"
#include "Peer.h"
#include "DHTConstants.h"
#include "DHTTaskQueue.h"
#include "DHTTaskFactory.h"
#include "DHTTask.h"
#include "LogFactory.h"
#include "Logger.h"
#include "util.h"
#include "a2functional.h"
#include "wallclock.h"
#include "fmt.h"

namespace aria2 {

DHTPeerAnnounceStorage::DHTPeerAnnounceStorage()
    : taskQueue_{nullptr}, taskFactory_{nullptr}
{
}

bool DHTPeerAnnounceStorage::InfoHashLess::
operator()(const std::shared_ptr<DHTPeerAnnounceEntry>& lhs,
           const std::shared_ptr<DHTPeerAnnounceEntry>& rhs)
{
  return memcmp(lhs->getInfoHash(), rhs->getInfoHash(), DHT_ID_LENGTH) < 0;
}

std::shared_ptr<DHTPeerAnnounceEntry>
DHTPeerAnnounceStorage::getPeerAnnounceEntry(const unsigned char* infoHash)
{
  auto entry = std::make_shared<DHTPeerAnnounceEntry>(infoHash);

  auto i = entries_.lower_bound(entry);

  if (i != entries_.end() &&
      memcmp(infoHash, (*i)->getInfoHash(), DHT_ID_LENGTH) == 0) {
    entry = *i;
  }
  else {
    entries_.insert(i, entry);
  }
  return entry;
}

void DHTPeerAnnounceStorage::addPeerAnnounce(const unsigned char* infoHash,
                                             const std::string& ipaddr,
                                             uint16_t port)
{
  A2_LOG_DEBUG(fmt("Adding %s:%u to peer announce list: infoHash=%s",
                   ipaddr.c_str(), port,
                   util::toHex(infoHash, DHT_ID_LENGTH).c_str()));
  getPeerAnnounceEntry(infoHash)->addPeerAddrEntry(PeerAddrEntry(ipaddr, port));
}

bool DHTPeerAnnounceStorage::contains(const unsigned char* infoHash) const
{
  auto entry = std::make_shared<DHTPeerAnnounceEntry>(infoHash);
  return std::binary_search(entries_.begin(), entries_.end(), entry,
                            InfoHashLess());
}

void DHTPeerAnnounceStorage::getPeers(std::vector<std::shared_ptr<Peer>>& peers,
                                      const unsigned char* infoHash)
{
  auto entry = std::make_shared<DHTPeerAnnounceEntry>(infoHash);

  auto i = entries_.find(entry);
  if (i != entries_.end()) {
    (*i)->getPeers(peers);
  }
}

void DHTPeerAnnounceStorage::handleTimeout()
{
  A2_LOG_DEBUG(fmt("Now purge peer announces(%lu entries) which are timed out.",
                   static_cast<unsigned long>(entries_.size())));
  std::for_each(std::begin(entries_), std::end(entries_),
                [](const std::shared_ptr<DHTPeerAnnounceEntry>& e) {
                  e->removeStalePeerAddrEntry(DHT_PEER_ANNOUNCE_PURGE_INTERVAL);
                });

  for (auto i = std::begin(entries_); i != std::end(entries_);) {
    if ((*i)->empty()) {
      entries_.erase(i++);
    }
    else {
      ++i;
    }
  }
  A2_LOG_DEBUG(fmt("Currently %lu peer announce entries",
                   static_cast<unsigned long>(entries_.size())));
}

void DHTPeerAnnounceStorage::announcePeer()
{
  A2_LOG_DEBUG("Now announcing peer.");
  for (auto& e : entries_) {
    if (e->getLastUpdated().difference(global::wallclock()) <
        DHT_PEER_ANNOUNCE_INTERVAL) {
      continue;
    }
    e->notifyUpdate();
    auto task = taskFactory_->createPeerAnnounceTask(e->getInfoHash());
    taskQueue_->addPeriodicTask2(task);
    A2_LOG_DEBUG(fmt("Added 1 peer announce: infoHash=%s",
                     util::toHex(e->getInfoHash(), DHT_ID_LENGTH).c_str()));
  }
}

void DHTPeerAnnounceStorage::setTaskQueue(DHTTaskQueue* taskQueue)
{
  taskQueue_ = taskQueue;
}

void DHTPeerAnnounceStorage::setTaskFactory(DHTTaskFactory* taskFactory)
{
  taskFactory_ = taskFactory;
}

} // namespace aria2
