/*
 * Project: JobMarket
 * Description: asynchronous Server/Controller/Client-approach to parallel computing, based on boost::asio
 * Copyright (C)  2012 Frederik Heber. All rights reserved.
 * 
 */

/*
 * OperationQueue.cpp
 *
 *  Created on: Apr 24, 2012
 *      Author: heber
 */


// include config.h
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

// boost asio needs specific operator new
#include <boost/asio.hpp>

//#include "CodePatterns/MemDebug.hpp"

#include <boost/bind.hpp>
#include <boost/lambda/lambda.hpp>
#include <string>

#include "CodePatterns/Log.hpp"
#include "CodePatterns/Observer/Observer.hpp"

#include "JobMarket/Operations/AsyncOperation.hpp"
#include "JobMarket/Operations/OperationQueue.hpp"

static void NoOp(const WorkerAddress) {}

// static instances
const boost::function<void (const WorkerAddress)> OperationQueue::NoOpCallback = boost::bind(&NoOp, _1);

size_t OperationQueue::max_connections = 1;

OperationQueue::OperationQueue_t::iterator OperationQueue::findOperation(AsyncOperation *op)
{
  OperationQueue_t::iterator iter =
      std::find_if(queue.begin(), queue.end(),
          boost::bind(&AsyncOp_ptr::get, boost::lambda::_1) == op);
  return iter;
}

void OperationQueue::push_back(AsyncOperation *&op, const WorkerAddress &address)
{
  if (op != NULL) {
    if (!IsBlockedFlag) {
      AsyncOp_ptr ptr(op); // this always prevents memory loss
      ptr->signOn(this);
      OperationQueue_t::iterator iter = queue.insert(queue.end(), ptr );
      op = NULL;
      AddressMap.insert( make_pair(*iter, address) );
      LaunchNextOp();
    } else {
      ELOG(1, "Queue is currently blocked, dropping operation "+op->getName()+".");
      delete op;
      op = NULL;
    }
  } else {
    ELOG(1, "Given operation pointer is NULL.");
  }
}

void OperationQueue::LaunchNextOp()
{
  // connection available?
  if (getNumberOfRunningOps() < max_connections) {
    if (!queue.empty()) {
      // only start operation when address is valid
      OperationQueue_t::iterator queueiter =
          std::find_if(queue.begin(), queue.end(),
              boost::bind(&AddressMap_t::count, boost::ref(AddressMap), boost::lambda::_1) );
      if (queueiter != queue.end()) {
        const AddressMap_t::iterator mapiter = AddressMap.find(*queueiter);
        ASSERT( mapiter != AddressMap.end(),
            "OperationQueue::LaunchNextOp() - cannot find connection "+toString((*queueiter)->getName())+" in AddressMap.");
        currentOpsAddress = mapiter->second;
        const AsyncOp_ptr ptr = mapiter->first;
        // always erase the op from the list of ones pending for launch
        AddressMap.erase(mapiter);
        // only launch when not a debug op
        if ((!currentOpsAddress.host.empty()) && (!currentOpsAddress.service.empty())) {
          LOG(2, "DEBUG: Launching next operation " << ptr->getName() << ".");
         (*ptr)(currentOpsAddress.host, currentOpsAddress.service);
        } else {
          LOG(3, "DEBUG: Skipping debug operation " << ptr->getName() << " with empty address.");
        }
      } else {
        LOG(2, "DEBUG: All remaining operations are already running.");
      }
    } else {
      LOG(2, "DEBUG: There are no more operations in the queue.");
    }
  } else {
    LOG(2, "DEBUG: Currently there are no free connections.");
  }
}

void OperationQueue::remove(AsyncOperation *op, Observer *observer)
{
  if (op != NULL) {
    OperationQueue_t::iterator iter = findOperation(op);
    if (iter != queue.end()) {
      // sign off and remove op
      if (observer != NULL)
        op->signOff(observer);
      queue.erase(iter);
    } else {
      ELOG(1, "Could not find Operation " << op->getName() << " in operation's queue.");
    }
  } else {
    ELOG(1, "Given operation pointer is NULL.");
  }
}

void OperationQueue::update(Observable *publisher)
{
  AsyncOperation *op = static_cast<AsyncOperation *>(publisher);
  if (op != NULL) {
    // check for error code of operation
    if (op->getStatus() != Operation::success) {
      // remove the worker from the queue
      failure_callback(currentOpsAddress);
      LOG(1, "INFO: We are notified that " << op->getName() << " has failed, removing ...");
    } else {
      LOG(1, "INFO: We are notified that " << op->getName() << " is done, removing ...");
    }
    // remove from queue
    remove(op, this);
    LaunchNextOp();
  }
}

void OperationQueue::recieveNotification(Observable *publisher, Notification_ptr notification)
{}

void OperationQueue::subjectKilled(Observable *publisher)
{
  AsyncOperation *op = static_cast<AsyncOperation *>(publisher);
  if (op != NULL) {
    ELOG(2, "DEBUG: AsyncOperation at " << publisher << " got killed before being done?");
    // remove from queue
    remove(op, this);
  }
}