/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * $Id$
 *
 * Description: Unordered buffer of messages that can be inserted such
 * that they can be dequeued after a given delta time has expired.
 *
 */

#ifndef MESSAGEBUFFER_H
#define MESSAGEBUFFER_H

#include "Global.hh"
#include "MessageBufferNode.hh"
#include "Consumer.hh"
#include "EventQueue.hh"
#include "Message.hh"
#include "PrioHeap.hh"
#include "util.hh"

class Chip;

class MessageBuffer {
public:
  // Constructors
  MessageBuffer();
  MessageBuffer(const Chip* chip_ptr); // The chip_ptr is ignored, but could be used for extra debugging

  // Use Default Destructor
  // ~MessageBuffer()

  // Public Methods

  static void printConfig(ostream& out) {}

  // TRUE if head of queue timestamp <= SystemTime
  bool isReady() const {
    return ((m_prio_heap.size() > 0) &&
            (m_prio_heap.peekMin().m_time <= g_eventQueue_ptr->getTime()));
  }

  bool areNSlotsAvailable(int n);
  int getPriority() { return m_priority_rank; }
  void setPriority(int rank) { m_priority_rank = rank; }
  void setConsumer(Consumer* consumer_ptr) { ASSERT(m_consumer_ptr==NULL); m_consumer_ptr = consumer_ptr; }
  void setDescription(const string& name) { m_name = name; }
  string getDescription() { return m_name;}

  Consumer* getConsumer() { return m_consumer_ptr; }

  const Message* peekAtHeadOfQueue() const;
  const Message* peek() const { return peekAtHeadOfQueue(); }
  const MsgPtr getMsgPtrCopy() const;
  const MsgPtr& peekMsgPtr() const { assert(isReady()); return m_prio_heap.peekMin().m_msgptr; }
  const MsgPtr& peekMsgPtrEvenIfNotReady() const {return m_prio_heap.peekMin().m_msgptr; }

  void enqueue(const MsgPtr& message) { enqueue(message, 1); }
  void enqueue(const MsgPtr& message, Time delta);
  //  void enqueueAbsolute(const MsgPtr& message, Time absolute_time);
  int dequeue_getDelayCycles(MsgPtr& message);  // returns delay cycles of the message
  void dequeue(MsgPtr& message);
  int dequeue_getDelayCycles();  // returns delay cycles of the message
  void dequeue() { pop(); }
  void pop();
  void recycle();
  bool isEmpty() const { return m_prio_heap.size() == 0; }

  void setOrdering(bool order) { m_strict_fifo = order; m_ordering_set = true; }
  void setSize(int size) {m_max_size = size;}
  int getSize();
  void setRandomization(bool random_flag) { m_randomization = random_flag; }

  void clear();

  void print(ostream& out) const;
  void printStats(ostream& out);
  void clearStats() { m_not_avail_count = 0; m_msg_counter = 0; }

private:
  // Private Methods
  int setAndReturnDelayCycles(MsgPtr& message);

  // Private copy constructor and assignment operator
  MessageBuffer(const MessageBuffer& obj);
  MessageBuffer& operator=(const MessageBuffer& obj);

  // Data Members (m_ prefix)
  Consumer* m_consumer_ptr;  // Consumer to signal a wakeup(), can be NULL
  PrioHeap<MessageBufferNode> m_prio_heap;
  string m_name;

  int m_max_size;
  int m_size;

  Time m_time_last_time_size_checked;
  int m_size_last_time_size_checked;

  // variables used so enqueues appear to happen imediately, while pop happen the next cycle
  Time m_time_last_time_enqueue;
  Time m_time_last_time_pop;
  int m_size_at_cycle_start;
  int m_msgs_this_cycle;

  int m_not_avail_count;  // count the # of times I didn't have N slots available
  int m_msg_counter;
  int m_priority_rank;
  bool m_strict_fifo;
  bool m_ordering_set;
  bool m_randomization;
  Time m_last_arrival_time;
};

// Output operator declaration
//template <class TYPE>
ostream& operator<<(ostream& out, const MessageBuffer& obj);

// ******************* Definitions *******************

// Output operator definition
extern inline
ostream& operator<<(ostream& out, const MessageBuffer& obj)
{
  obj.print(out);
  out << flush;
  return out;
}

#endif //MESSAGEBUFFER_H