/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
/**
 * Copyright (C) 2013 Regents of the University of California.
 * @author: Jeff Thompson <jefft0@remap.ucla.edu>
 * See COPYING for copyright and distribution information.
 */

#ifndef NDN_NODE_HPP
#define NDN_NODE_HPP

#include "common.hpp"
#include "interest.hpp"
#include "data.hpp"
#include "forwarding-flags.hpp"
#include "transport/transport.hpp"


namespace ndn {

/**
 * An OnData function object is used to pass a callback to expressInterest.
 */
typedef func_lib::function<void(const ptr_lib::shared_ptr<const Interest>&, const ptr_lib::shared_ptr<Data>&)> OnData;

/**
 * An OnTimeout function object is used to pass a callback to expressInterest.
 */
typedef func_lib::function<void(const ptr_lib::shared_ptr<const Interest>&)> OnTimeout;

/**
 * An OnInterest function object is used to pass a callback to registerPrefix.
 */
typedef func_lib::function<void
  (const ptr_lib::shared_ptr<const Name>&, const ptr_lib::shared_ptr<const Interest>&, Transport&, uint64_t)> OnInterest;

/**
 * An OnRegisterFailed function object is used to report when registerPrefix fails.
 */
typedef func_lib::function<void(const ptr_lib::shared_ptr<const Name>&)> OnRegisterFailed;

class Face;
    
class Node {
public:
  struct Error : public std::runtime_error { Error(const std::string &what) : std::runtime_error(what) {} };

  /**
   * Create a new Node for communication with an NDN hub with the given Transport object and connectionInfo.
   * @param transport A shared_ptr to a Transport object used for communication.
   * @param transport A shared_ptr to a Transport::ConnectionInfo to be used to connect to the transport.
   */
  Node(const ptr_lib::shared_ptr<Transport>& transport);

  /**
   * @brief Alternative (special use case) version of the constructor, can be used to aggregate
   *        several Faces within one processing thread
   *
   * <code>
   *     Face face1(...);
   *     Face face2(..., face1.getAsyncService());
   *
   *     // Now the following ensures that events on both faces are processed
   *     face1.processEvents();
   * </code>
   */
  Node(const ptr_lib::shared_ptr<Transport>& transport, const ptr_lib::shared_ptr<boost::asio::io_service> &ioService);
  
  /**
   * Send the Interest through the transport, read the entire response and call onData(interest, data).
   * @param interest A reference to the Interest.  This copies the Interest.
   * @param onData A function object to call when a matching data packet is received.  This copies the function object, so you may need to
   * use func_lib::ref() as appropriate.
   * @param onTimeout A function object to call if the interest times out.  If onTimeout is an empty OnTimeout(), this does not use it.
   * This copies the function object, so you may need to use func_lib::ref() as appropriate.
   * @param wireFormat A WireFormat object used to encode the message.
   * @return The pending interest ID which can be used with removePendingInterest.
   */
  uint64_t 
  expressInterest(const Interest& interest, const OnData& onData, const OnTimeout& onTimeout);
  
  /**
   * Remove the pending interest entry with the pendingInterestId from the pending interest table.
   * This does not affect another pending interest with a different pendingInterestId, even it if has the same interest name.
   * If there is no entry with the pendingInterestId, do nothing.
   * @param pendingInterestId The ID returned from expressInterest.
   */
  void
  removePendingInterest(uint64_t pendingInterestId);
  
  /**
   * Register prefix with the connected NDN hub and call onInterest when a matching interest is received.
   * @param prefix A reference to a Name for the prefix to register.  This copies the Name.
   * @param onInterest A function object to call when a matching interest is received.  This copies the function object, so you may need to
   * use func_lib::ref() as appropriate.
   * @param onRegisterFailed A function object to call if failed to retrieve the connected hub’s ID or failed to register the prefix.
   * This calls onRegisterFailed(prefix) where prefix is the prefix given to registerPrefix.
   * @param flags The flags for finer control of which interests are forward to the application.
   * @param wireFormat A WireFormat object used to encode the message.
   * @return The registered prefix ID which can be used with removeRegisteredPrefix.
   */
  uint64_t 
  registerPrefix
    (const Name& prefix, const OnInterest& onInterest, const OnRegisterFailed& onRegisterFailed, const ForwardingFlags& flags);

  /**
   * Remove the registered prefix entry with the registeredPrefixId from the pending interest table.  
   * This does not affect another registered prefix with a different registeredPrefixId, even it if has the same prefix name.
   * If there is no entry with the registeredPrefixId, do nothing.
   * @param registeredPrefixId The ID returned from registerPrefix.
   */
  void
  removeRegisteredPrefix(uint64_t registeredPrefixId);

   /**
   * @brief Publish data packet
   *
   * This method can be called to satisfy the incoming Interest or to put Data packet into the cache
   * of the local NDN forwarder
   */
  void
  put(const Data &data);
 
  /**
   * Process any data to receive or call timeout callbacks.
   *
   * This call will block forever (default timeout == 0) to process IO on the face.
   * To exit, one expected to call face.shutdown() from one of the callback methods.
   *
   * If positive timeout is specified, then processEvents will exit after this timeout,
   * if not stopped earlier with face.shutdown() or when all active events finish.
   * The call can be called repeatedly, if desired.
   *
   * If negative timeout is specified, then processEvents will not block and process only pending
   * events.
   *
   * @throw This may throw an exception for reading data or in the callback for processing the data.  If you
   * call this from an main event loop, you may want to catch and log/disregard all exceptions.
   */
  void 
  processEvents(Milliseconds timeout = 0, bool keepThread = false);
  
  const ptr_lib::shared_ptr<Transport>& 
  getTransport() { return transport_; }
  
  void 
  shutdown();

private:
  void 
  onReceiveElement(const Block &wire);

  struct ProcessEventsTimeout {};  
  static void
  fireProcessEventsTimeout(const boost::system::error_code& error);

private:
  class PendingInterest {
  public:
    /**
     * Create a new PitEntry and set the timeoutTime_ based on the current time and the interest lifetime.
     * @param pendingInterestId A unique ID for this entry, which you should get with getNextPendingInteresId().
     * @param interest A shared_ptr for the interest.
     * @param onData A function object to call when a matching data packet is received.
     * @param onTimeout A function object to call if the interest times out.  If onTimeout is an empty OnTimeout(), this does not use it.
     */
    PendingInterest
      (uint64_t pendingInterestId, const ptr_lib::shared_ptr<const Interest>& interest, const OnData& onData, 
       const OnTimeout& onTimeout);
    
    /**
     * Return the next unique pending interest ID.
     */
    static uint64_t 
    getNextPendingInterestId()
    {
      return ++lastPendingInterestId_;
    }
    
    /**
     * Return the pendingInterestId given to the constructor.
     */
    uint64_t 
    getPendingInterestId() { return pendingInterestId_; }
    
    const ptr_lib::shared_ptr<const Interest>& 
    getInterest() { return interest_; }
    
    const OnData& 
    getOnData() { return onData_; }
    
    /**
     * Check if this interest is timed out.
     * @param nowMilliseconds The current time in milliseconds from ndn_getNowMilliseconds.
     * @return true if this interest timed out, otherwise false.
     */
    bool 
    isTimedOut(MillisecondsSince1970 nowMilliseconds)
    {
      return timeoutTimeMilliseconds_ >= 0.0 && nowMilliseconds >= timeoutTimeMilliseconds_;
    }

    /**
     * Call onTimeout_ (if defined).  This ignores exceptions from the onTimeout_.
     */
    void 
    callTimeout();
    
  private:
    static uint64_t lastPendingInterestId_; /**< A class variable used to get the next unique ID. */

    uint64_t pendingInterestId_;            /**< A unique identifier for this entry so it can be deleted */
    ptr_lib::shared_ptr<const Interest> interest_;
    const OnData onData_;
    const OnTimeout onTimeout_;
    
    MillisecondsSince1970 timeoutTimeMilliseconds_; /**< The time when the interest times out in milliseconds according to ndn_getNowMilliseconds, or -1 for no timeout. */
  };

  class RegisteredPrefix {
  public:
    /**
     * Create a new PrefixEntry.
     * @param registeredPrefixId A unique ID for this entry, which you should get with getNextRegisteredPrefixId().
     * @param prefix A shared_ptr for the prefix.
     * @param onInterest A function object to call when a matching data packet is received.
     */
    RegisteredPrefix(uint64_t registeredPrefixId, const ptr_lib::shared_ptr<const Name>& prefix, const OnInterest& onInterest)
      : registeredPrefixId_(registeredPrefixId)
      , prefix_(prefix)
      , onInterest_(onInterest)
    {
    }
    
    /**
     * Return the next unique entry ID.
     */
    static uint64_t 
    getNextRegisteredPrefixId()
    {
      return ++lastRegisteredPrefixId_;
    }
    
    /**
     * Return the registeredPrefixId given to the constructor.
     */
    uint64_t 
    getRegisteredPrefixId()
    {
      return registeredPrefixId_;
    }
    
    const ptr_lib::shared_ptr<const Name>& 
    getPrefix()
    {
      return prefix_;
    }
    
    const OnInterest& 
    getOnInterest()
    {
      return onInterest_;
    }
    
  private:
    static uint64_t lastRegisteredPrefixId_; /**< A class variable used to get the next unique ID. */

    uint64_t registeredPrefixId_;            /**< A unique identifier for this entry so it can be deleted */
    ptr_lib::shared_ptr<const Name> prefix_;
    const OnInterest onInterest_;
  };
  
  typedef std::vector<ptr_lib::shared_ptr<PendingInterest> > PendingInterestTable;
  typedef std::vector<ptr_lib::shared_ptr<RegisteredPrefix> > RegisteredPrefixTable;
  
  /**
   * Find the entry from the pit_ where the name conforms to the entry's interest selectors, and
   * the entry interest name is the longest that matches name.
   * @param name The name to find the interest for (from the incoming data packet).
   * @return The index in pit_ of the pit entry, or -1 if not found.
   */
  PendingInterestTable::iterator 
  getEntryIndexForExpressedInterest(const Name& name);
  
  /**
   * Find the first entry from the registeredPrefixTable_ where the entry prefix is the longest that matches name.
   * @param name The name to find the PrefixEntry for (from the incoming interest packet).
   * @return A pointer to the entry, or 0 if not found.
   */
  RegisteredPrefixTable::iterator
  getEntryForRegisteredPrefix(const Name& name);

  /**
   * Do the work of registerPrefix once we know we are connected with an ndndId_.
   * @param registeredPrefixId The PrefixEntry::getNextRegisteredPrefixId() which registerPrefix got so it could return it to the caller.
   * @param prefix
   * @param onInterest
   * @param onRegisterFailed
   * @param flags
   * @param wireFormat
   */  
  void 
  registerPrefixHelper
    (uint64_t registeredPrefixId, const ptr_lib::shared_ptr<const Name>& prefix, const OnInterest& onInterest, 
     const OnRegisterFailed& onRegisterFailed, const ForwardingFlags& flags);

  /**
   * @brief Final stage of prefix registration, invoked when registration succeeded
   *
   * This method actually sets entry in a local interest filter table
   */
  void
  registerPrefixFinal(uint64_t registeredPrefixId,
                      const ptr_lib::shared_ptr<const Name>& prefix,
                      const OnInterest& onInterest,
                      const OnRegisterFailed& onRegisterFailed,
                      const ptr_lib::shared_ptr<const Interest>&, const ptr_lib::shared_ptr<Data>&);
  
  void
  checkPitExpire();
  
private:
  ptr_lib::shared_ptr<boost::asio::io_service> ioService_;
  ptr_lib::shared_ptr<boost::asio::io_service::work> ioServiceWork_; // needed if thread needs to be preserved
  ptr_lib::shared_ptr<boost::asio::deadline_timer> pitTimeoutCheckTimer_;
  bool pitTimeoutCheckTimerActive_;
  ptr_lib::shared_ptr<boost::asio::deadline_timer> processEventsTimeoutTimer_;
  
  ptr_lib::shared_ptr<Transport> transport_;

  PendingInterestTable pendingInterestTable_;
  RegisteredPrefixTable registeredPrefixTable_;
  Interest ndndIdFetcherInterest_;

  int64_t faceId_; // internal face ID (needed for prefix de-registration)
  Buffer ndndId_;
};

} // namespace ndn

#endif