/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2011-2015  Regents of the University of California.
 *
 * This file is part of ndnSIM. See AUTHORS for complete list of ndnSIM authors and
 * contributors.
 *
 * ndnSIM 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 of the License, or (at your option) any later version.
 *
 * ndnSIM 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
 * ndnSIM, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 **/

#ifndef NDN_CONTENT_STORE_H
#define NDN_CONTENT_STORE_H

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

#include "ns3/object.h"
#include "ns3/ptr.h"
#include "ns3/traced-callback.h"

#include <tuple>

namespace ns3 {

class Packet;

namespace ndn {

class ContentStore;

/**
 * @ingroup ndn
 * @defgroup ndn-cs Content Store
 */

/**
 * @ingroup ndn-cs
 * @brief Namespace for ContentStore operations
 */
namespace cs {

/**
 * @ingroup ndn-cs
 * @brief NDN content store entry
 */
class Entry : public SimpleRefCount<Entry> {
public:
  /**
   * \brief Construct content store entry
   *
   * \param header Parsed Data header
   * \param packet Original Ndn packet
   *
   * The constructor will make a copy of the supplied packet and calls
   * RemoveHeader and RemoveTail on the copy.
   */
  Entry(Ptr<ContentStore> cs, shared_ptr<const Data> data);

  /**
   * \brief Get prefix of the stored entry
   * \returns prefix of the stored entry
   */
  const Name&
  GetName() const;

  /**
   * \brief Get Data of the stored entry
   * \returns Data of the stored entry
   */
  shared_ptr<const Data>
  GetData() const;

  /**
   * @brief Get pointer to access store, to which this entry is added
   */
  Ptr<ContentStore>
  GetContentStore();

private:
  Ptr<ContentStore> m_cs;        ///< \brief content store to which entry is added
  shared_ptr<const Data> m_data; ///< \brief non-modifiable Data
};

} // namespace cs

/**
 * @ingroup ndn-cs
 * \brief Base class for NDN content store
 *
 * Particular implementations should implement Lookup, Add, and Print methods
 */
class ContentStore : public Object {
public:
  /**
   * \brief Interface ID
   *
   * \return interface ID
   */
  static TypeId
  GetTypeId();

  /**
   * @brief Virtual destructor
   */
  virtual ~ContentStore();

  /**
   * \brief Find corresponding CS entry for the given interest
   *
   * \param interest Interest for which matching content store entry
   * will be searched
   *
   * If an entry is found, it is promoted to the top of most recent
   * used entries index, \see m_contentStore
   */
  virtual shared_ptr<Data>
  Lookup(shared_ptr<const Interest> interest) = 0;

  /**
   * \brief Add a new content to the content store.
   *
   * \param header Fully parsed Data
   * \param packet Fully formed Ndn packet to add to content store
   * (will be copied and stripped down of headers)
   * @returns true if an existing entry was updated, false otherwise
   */
  virtual bool
  Add(shared_ptr<const Data> data) = 0;

  // /*
  //  * \brief Add a new content to the content store.
  //  *
  //  * \param header Interest header for which an entry should be removed
  //  * @returns true if an existing entry was removed, false otherwise
  //  */
  // virtual bool
  // Remove (shared_ptr<Interest> header) = 0;

  /**
   * \brief Print out content store entries
   */
  virtual void
  Print(std::ostream& os) const = 0;

  /**
   * @brief Get number of entries in content store
   */
  virtual uint32_t
  GetSize() const = 0;

  /**
   * @brief Return first element of content store (no order guaranteed)
   */
  virtual Ptr<cs::Entry>
  Begin() = 0;

  /**
   * @brief Return item next after last (no order guaranteed)
   */
  virtual Ptr<cs::Entry>
  End() = 0;

  /**
   * @brief Advance the iterator
   */
  virtual Ptr<cs::Entry> Next(Ptr<cs::Entry>) = 0;

  ////////////////////////////////////////////////////////////////////////////
  ////////////////////////////////////////////////////////////////////////////
  ////////////////////////////////////////////////////////////////////////////

  /**
   * @brief Static call to cheat python bindings
   */
  static inline Ptr<ContentStore>
  GetContentStore(Ptr<Object> node);

protected:
  TracedCallback<shared_ptr<const Interest>,
                 shared_ptr<const Data>> m_cacheHitsTrace; ///< @brief trace of cache hits

  TracedCallback<shared_ptr<const Interest>> m_cacheMissesTrace; ///< @brief trace of cache misses
};

inline std::ostream&
operator<<(std::ostream& os, const ContentStore& cs)
{
  cs.Print(os);
  return os;
}

inline Ptr<ContentStore>
ContentStore::GetContentStore(Ptr<Object> node)
{
  return node->GetObject<ContentStore>();
}

} // namespace ndn
} // namespace ns3

#include <boost/functional/hash.hpp>
namespace boost {
inline std::size_t
hash_value(const ::ndn::name::Component component)
{
  return boost::hash_range(component.wireEncode().wire(),
                           component.wireEncode().wire() + component.wireEncode().size());
}
}

#endif // NDN_CONTENT_STORE_H