/*
 * 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.
 */

/*
 * $Id$
 */

#include "mem/ruby/buffers/MessageBuffer.hh"
#include "mem/ruby/config/RubyConfig.hh"
#include "mem/ruby/system/System.hh"

MessageBuffer::MessageBuffer()
{
  m_msg_counter = 0;
  m_consumer_ptr = NULL;
  m_ordering_set = false;
  m_strict_fifo = true;
  m_size = 0;
  m_max_size = -1;
  m_last_arrival_time = 0;
  m_randomization = true;
  m_size_last_time_size_checked = 0;
  m_time_last_time_size_checked = 0;
  m_time_last_time_enqueue = 0;
  m_time_last_time_pop = 0;
  m_size_at_cycle_start = 0;
  m_msgs_this_cycle = 0;
  m_not_avail_count = 0;
  m_priority_rank = 0;
}

MessageBuffer::MessageBuffer(const Chip* chip_ptr)  // The chip_ptr is ignored, but could be used for extra debugging
{
  m_msg_counter = 0;
  m_consumer_ptr = NULL;
  m_ordering_set = false;
  m_strict_fifo = true;
  m_size = 0;
  m_max_size = -1;
  m_last_arrival_time = 0;
  m_randomization = true;
  m_size_last_time_size_checked = 0;
  m_time_last_time_size_checked = 0;
  m_time_last_time_enqueue = 0;
  m_time_last_time_pop = 0;
  m_size_at_cycle_start = 0;
  m_msgs_this_cycle = 0;
  m_not_avail_count = 0;
  m_priority_rank = 0;
}

int MessageBuffer::getSize()
{
  if(m_time_last_time_size_checked == g_eventQueue_ptr->getTime()){
    return m_size_last_time_size_checked;
  } else {
    m_time_last_time_size_checked = g_eventQueue_ptr->getTime();
    m_size_last_time_size_checked = m_size;
    return m_size;
  }
}

bool MessageBuffer::areNSlotsAvailable(int n)
{

  // fast path when message buffers have infinite size
  if(m_max_size == -1) {
    return true;
  }

  // determine my correct size for the current cycle
  // pop operations shouldn't effect the network's visible size until next cycle,
  // but enqueue operations effect the visible size immediately
  int current_size = max(m_size_at_cycle_start, m_size);
  if (m_time_last_time_pop < g_eventQueue_ptr->getTime()) {  // no pops this cycle - m_size is correct
    current_size = m_size;
  } else {
    if (m_time_last_time_enqueue < g_eventQueue_ptr->getTime()) {  // no enqueues this cycle - m_size_at_cycle_start is correct
      current_size = m_size_at_cycle_start;
    } else {  // both pops and enqueues occured this cycle - add new enqueued msgs to m_size_at_cycle_start
      current_size = m_size_at_cycle_start+m_msgs_this_cycle;
    }
  }

  // now compare the new size with our max size
  if(current_size+n <= m_max_size){
    return true;
  } else {
    DEBUG_MSG(QUEUE_COMP,MedPrio,n);
    DEBUG_MSG(QUEUE_COMP,MedPrio,current_size);
    DEBUG_MSG(QUEUE_COMP,MedPrio,m_size);
    DEBUG_MSG(QUEUE_COMP,MedPrio,m_max_size);
    m_not_avail_count++;
    return false;
  }
}

const MsgPtr MessageBuffer::getMsgPtrCopy() const
{
  assert(isReady());

  MsgPtr temp_msg;
  temp_msg = *(m_prio_heap.peekMin().m_msgptr.ref());
  assert(temp_msg.ref() != NULL);
  return temp_msg;
}

const Message* MessageBuffer::peekAtHeadOfQueue() const
{
  const Message* msg_ptr;
  DEBUG_NEWLINE(QUEUE_COMP,MedPrio);

  DEBUG_MSG(QUEUE_COMP,MedPrio,"Peeking at head of queue " + m_name + " time: "
            + int_to_string(g_eventQueue_ptr->getTime()) + ".");
  assert(isReady());

  msg_ptr = m_prio_heap.peekMin().m_msgptr.ref();
  assert(msg_ptr != NULL);

  DEBUG_EXPR(QUEUE_COMP,MedPrio,*msg_ptr);
  DEBUG_NEWLINE(QUEUE_COMP,MedPrio);
  return msg_ptr;
}

// FIXME - move me somewhere else
int random_time()
{
  int time = 1;
  time += random() & 0x3;  // [0...3]
  if ((random() & 0x7) == 0) {  // 1 in 8 chance
    time += 100 + (random() % 0xf); // 100 + [1...15]
  }
  return time;
}

void MessageBuffer::enqueue(const MsgPtr& message, Time delta)
{
  DEBUG_NEWLINE(QUEUE_COMP,HighPrio);
  DEBUG_MSG(QUEUE_COMP,HighPrio,"enqueue " + m_name + " time: "
            + int_to_string(g_eventQueue_ptr->getTime()) + ".");
  DEBUG_EXPR(QUEUE_COMP,MedPrio,message);
  DEBUG_NEWLINE(QUEUE_COMP,HighPrio);

  m_msg_counter++;
  m_size++;

  // record current time incase we have a pop that also adjusts my size
  if (m_time_last_time_enqueue < g_eventQueue_ptr->getTime()) {
    m_msgs_this_cycle = 0;  // first msg this cycle
    m_time_last_time_enqueue = g_eventQueue_ptr->getTime();
  }
  m_msgs_this_cycle++;

  //  ASSERT(m_max_size == -1 || m_size <= m_max_size + 1);
  // the plus one is a kluge because of a SLICC issue

  if (!m_ordering_set) {
    //    WARN_EXPR(*this);
    WARN_EXPR(m_name);
    ERROR_MSG("Ordering property of this queue has not been set");
  }

  // Calculate the arrival time of the message, that is, the first
  // cycle the message can be dequeued.
//  printf ("delta %i \n", delta);
  assert(delta>0);
  Time current_time = g_eventQueue_ptr->getTime();
  Time arrival_time = 0;
  if (!RubySystem::getRandomization() || (m_randomization == false)) {
    // No randomization
    arrival_time = current_time + delta;

  } else {
    // Randomization - ignore delta
    if (m_strict_fifo) {
      if (m_last_arrival_time < current_time) {
        m_last_arrival_time = current_time;
      }
      arrival_time = m_last_arrival_time + random_time();
    } else {
      arrival_time = current_time + random_time();
    }
  }

  // Check the arrival time
  assert(arrival_time > current_time);
  if (m_strict_fifo) {
    if (arrival_time >= m_last_arrival_time) {

    } else {
      WARN_EXPR(*this);
      WARN_EXPR(m_name);
      WARN_EXPR(current_time);
      WARN_EXPR(delta);
      WARN_EXPR(arrival_time);
      WARN_EXPR(m_last_arrival_time);
      ERROR_MSG("FIFO ordering violated");
    }
  }
  m_last_arrival_time = arrival_time;

  // compute the delay cycles and set enqueue time
  Message* msg_ptr = NULL;
  msg_ptr = message.mod_ref();
  assert(msg_ptr != NULL);
  assert(g_eventQueue_ptr->getTime() >= msg_ptr->getLastEnqueueTime());  // ensure we aren't dequeued early
  msg_ptr->setDelayedCycles((g_eventQueue_ptr->getTime() - msg_ptr->getLastEnqueueTime())+msg_ptr->getDelayedCycles());
  msg_ptr->setLastEnqueueTime(arrival_time);

  // Insert the message into the priority heap
  MessageBufferNode thisNode(arrival_time, m_msg_counter, message);
  m_prio_heap.insert(thisNode);

  DEBUG_NEWLINE(QUEUE_COMP,HighPrio);
  DEBUG_MSG(QUEUE_COMP,HighPrio,"enqueue " + m_name
            + " with arrival_time " + int_to_string(arrival_time)
            + " cur_time: " + int_to_string(g_eventQueue_ptr->getTime()) + ".");
  DEBUG_EXPR(QUEUE_COMP,MedPrio,message);
  DEBUG_NEWLINE(QUEUE_COMP,HighPrio);

  // Schedule the wakeup
  if (m_consumer_ptr != NULL) {
    g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, arrival_time);
  } else {
    WARN_EXPR(*this);
    WARN_EXPR(m_name);
    ERROR_MSG("No consumer");
  }
}

int MessageBuffer::dequeue_getDelayCycles(MsgPtr& message)
{
  int delay_cycles = -1;  // null value

  dequeue(message);

  // get the delay cycles
  delay_cycles = setAndReturnDelayCycles(message);

  assert(delay_cycles >= 0);
  return delay_cycles;
}

void MessageBuffer::dequeue(MsgPtr& message)
{
  DEBUG_MSG(QUEUE_COMP,MedPrio,"dequeue from " + m_name);
  message = m_prio_heap.peekMin().m_msgptr;

  pop();
  DEBUG_EXPR(QUEUE_COMP,MedPrio,message);
}

int MessageBuffer::dequeue_getDelayCycles()
{
  int delay_cycles = -1;  // null value

  // get MsgPtr of the message about to be dequeued
  MsgPtr message = m_prio_heap.peekMin().m_msgptr;

  // get the delay cycles
  delay_cycles = setAndReturnDelayCycles(message);

  dequeue();

  assert(delay_cycles >= 0);
  return delay_cycles;
}

void MessageBuffer::pop()
{
  DEBUG_MSG(QUEUE_COMP,MedPrio,"pop from " + m_name);
  assert(isReady());
  m_prio_heap.extractMin();
  // record previous size and time so the current buffer size isn't adjusted until next cycle
  if (m_time_last_time_pop < g_eventQueue_ptr->getTime()) {
    m_size_at_cycle_start = m_size;
    m_time_last_time_pop = g_eventQueue_ptr->getTime();
  }
  m_size--;
}

void MessageBuffer::clear()
{
  while(m_prio_heap.size() > 0){
    m_prio_heap.extractMin();
  }

  ASSERT(m_prio_heap.size() == 0);

  m_msg_counter = 0;
  m_size = 0;
  m_time_last_time_enqueue = 0;
  m_time_last_time_pop = 0;
  m_size_at_cycle_start = 0;
  m_msgs_this_cycle = 0;
}

void MessageBuffer::recycle()
{
  //  const int RubyConfig::getRecycleLatency() = 3;
  DEBUG_MSG(QUEUE_COMP,MedPrio,"recycling " + m_name);
  assert(isReady());
  MessageBufferNode node = m_prio_heap.extractMin();
  node.m_time = g_eventQueue_ptr->getTime() + m_recycle_latency;
  m_prio_heap.insert(node);
  g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, g_eventQueue_ptr->getTime() + m_recycle_latency);
}

int MessageBuffer::setAndReturnDelayCycles(MsgPtr& message)
{
  int delay_cycles = -1;  // null value

  // get the delay cycles of the message at the top of the queue
  Message* msg_ptr = message.ref();

  // this function should only be called on dequeue
  // ensure the msg hasn't been enqueued
  assert(msg_ptr->getLastEnqueueTime() <= g_eventQueue_ptr->getTime());
  msg_ptr->setDelayedCycles((g_eventQueue_ptr->getTime() - msg_ptr->getLastEnqueueTime())+msg_ptr->getDelayedCycles());
  delay_cycles = msg_ptr->getDelayedCycles();

  assert(delay_cycles >= 0);
  return delay_cycles;
}

void MessageBuffer::print(ostream& out) const
{
  out << "[MessageBuffer: ";
  if (m_consumer_ptr != NULL) {
    out << " consumer-yes ";
  }
  out << m_prio_heap << "] " << m_name << endl;
}

void MessageBuffer::printStats(ostream& out)
{
  out << "MessageBuffer: " << m_name << " stats - msgs:" << m_msg_counter << " full:" << m_not_avail_count << endl;
}