/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2012 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 */

#ifndef NDN_CONTENT_STORE_WITH_FRESHNESS_H_
#define NDN_CONTENT_STORE_WITH_FRESHNESS_H_

#include "ns3/ndnSIM/model/ndn-common.hpp"

#include "content-store-impl.hpp"

#include "../../utils/trie/multi-policy.hpp"
#include "custom-policies/freshness-policy.hpp"

namespace ns3 {
namespace ndn {
namespace cs {

/**
 * @ingroup ndn-cs
 * @brief Special content store realization that honors Freshness parameter in Data packets
 */
template<class Policy>
class ContentStoreWithFreshness
  : public ContentStoreImpl<ndnSIM::
                              multi_policy_traits<boost::mpl::
                                                    vector2<Policy,
                                                            ndnSIM::freshness_policy_traits>>> {
public:
  typedef ContentStoreImpl<ndnSIM::multi_policy_traits<boost::mpl::
                                                         vector2<Policy,
                                                                 ndnSIM::freshness_policy_traits>>>
    super;

  typedef typename super::policy_container::template index<1>::type freshness_policy_container;

  static TypeId
  GetTypeId();

  virtual inline void
  Print(std::ostream& os) const;

  virtual inline bool
  Add(shared_ptr<const Data> data);

private:
  inline void
  CleanExpired();

  inline void
  RescheduleCleaning();

private:
  static LogComponent g_log; ///< @brief Logging variable

  EventId m_cleanEvent;
  Time m_scheduledCleaningTime;
};

//////////////////////////////////////////
////////// Implementation ////////////////
//////////////////////////////////////////

template<class Policy>
LogComponent ContentStoreWithFreshness<Policy>::g_log = LogComponent(("ndn.cs.Freshness."
                                                                      + Policy::GetName()).c_str());

template<class Policy>
TypeId
ContentStoreWithFreshness<Policy>::GetTypeId()
{
  static TypeId tid = TypeId(("ns3::ndn::cs::Freshness::" + Policy::GetName()).c_str())
                        .SetGroupName("Ndn")
                        .SetParent<super>()
                        .template AddConstructor<ContentStoreWithFreshness<Policy>>()

    // trace stuff here
    ;

  return tid;
}

template<class Policy>
inline bool
ContentStoreWithFreshness<Policy>::Add(shared_ptr<const Data> data)
{
  bool ok = super::Add(data);
  if (!ok)
    return false;

  NS_LOG_DEBUG(data->GetName() << " added to cache");
  RescheduleCleaning();
  return true;
}

template<class Policy>
inline void
ContentStoreWithFreshness<Policy>::RescheduleCleaning()
{
  const freshness_policy_container& freshness =
    this->getPolicy().template get<freshness_policy_container>();

  if (freshness.size() > 0) {
    Time nextStateTime =
      freshness_policy_container::policy_base::get_freshness(&(*freshness.begin()));

    if (m_scheduledCleaningTime.IsZero() ||      // if not yet scheduled
        m_scheduledCleaningTime > nextStateTime) // if new item expire sooner than already scheduled
    {
      if (m_cleanEvent.IsRunning()) {
        Simulator::Remove(m_cleanEvent); // just canceling would not clean up list of events
      }

      // NS_LOG_DEBUG ("Next event in: " << (nextStateTime - Now ()).ToDouble (Time::S) << "s");
      m_cleanEvent = Simulator::Schedule(nextStateTime - Now(),
                                         &ContentStoreWithFreshness<Policy>::CleanExpired, this);
      m_scheduledCleaningTime = nextStateTime;
    }
  }
  else {
    if (m_cleanEvent.IsRunning()) {
      Simulator::Remove(m_cleanEvent); // just canceling would not clean up list of events
    }
  }
}

template<class Policy>
inline void
ContentStoreWithFreshness<Policy>::CleanExpired()
{
  freshness_policy_container& freshness =
    this->getPolicy().template get<freshness_policy_container>();

  // NS_LOG_LOGIC (">> Cleaning: Total number of items:" << this->getPolicy ().size () << ", items
  // with freshness: " << freshness.size ());
  Time now = Simulator::Now();

  while (!freshness.empty()) {
    typename freshness_policy_container::iterator entry = freshness.begin();

    if (freshness_policy_container::policy_base::get_freshness(&(*entry))
        <= now) // is the record stale?
    {
      super::erase(&(*entry));
    }
    else
      break; // nothing else to do. All later records will not be stale
  }
  // NS_LOG_LOGIC ("<< Cleaning: Total number of items:" << this->getPolicy ().size () << ", items
  // with freshness: " << freshness.size ());

  m_scheduledCleaningTime = Time();
  RescheduleCleaning();
}

template<class Policy>
void
ContentStoreWithFreshness<Policy>::Print(std::ostream& os) const
{
  // const freshness_policy_container &freshness = this->getPolicy ().template
  // get<freshness_policy_container> ();

  for (typename super::policy_container::const_iterator item = this->getPolicy().begin();
       item != this->getPolicy().end(); item++) {
    Time ttl = freshness_policy_container::policy_base::get_freshness(&(*item)) - Simulator::Now();
    os << item->payload()->GetName() << "(left: " << ttl.ToDouble(Time::S) << "s)" << std::endl;
  }
}

} // namespace cs
} // namespace ndn
} // namespace ns3

#endif // NDN_CONTENT_STORE_WITH_FRESHNESS_H_