/*
 * Project: MoleCuilder
 * Description: creates and alters molecular systems
 * Copyright (C) 2012 University of Bonn. All rights reserved.
 * Please see the LICENSE file or "Copyright notice" in builder.cpp for details.
 */

/*
 * \file PoolWorker.cpp
 *
 * This file strongly follows the Serialization example from the boost::asio
 * library (see client.cpp).
 *
 *  Created on: Feb 28, 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/lexical_cast.hpp>
#include <iostream>
#include <vector>
#include "Connection.hpp" // Must come before boost/serialization headers.
#include <boost/serialization/vector.hpp>
#include "CodePatterns/Info.hpp"
#include "CodePatterns/Log.hpp"
#include "Jobs/FragmentJob.hpp"
#include "Jobs/MPQCCommandJob.hpp"
#include "Jobs/SystemCommandJob.hpp"
#include "Operations/Workers/EnrollInPoolOperation.hpp"
#include "Operations/Workers/RemoveFromPoolOperation.hpp"
#include "Operations/Workers/SubmitResultOperation.hpp"
#include "Results/FragmentResult.hpp"
#include "PoolWorker.hpp"

/** Helper function to enforce binding of PoolWorker to possible derived
 * FragmentJob classes.
 */
void dummyInit() {
  SystemCommandJob("/bin/false", "something", JobId::IllegalJob);
  MPQCCommandJob("nofile", JobId::IllegalJob);
}

/** Constructor for class PoolWorker.
 *
 * We automatically connect to the given pool and enroll.
 *
 * @param _io_service io service for creating connections
 * @param _host host part of MyAddress of pool to connect to
 * @param _service service part of MyAddress of pool to connect to
 * @param listenhost host part of MyAddress of this instance for listening to pool connections
 * @param listenservice seervice part of MyAddress of this instance for listening to pool connections
 */
PoolWorker::PoolWorker(
    boost::asio::io_service& _io_service,
    const std::string& _host,
    const std::string& _service,
    const std::string& listenhost,
    const std::string& listenservice) :
  io_service(_io_service),
  PoolListener(_io_service, boost::lexical_cast<unsigned short>(listenservice), *this),
  MyAddress(listenhost, listenservice),
  ServerAddress(_host, _service),
  connection_(_io_service),
  failed(boost::bind(&ExitflagContainer::setExitflag, this, ExitflagContainer::ErrorFlag))
{
  Info info(__FUNCTION__);

  // always enroll and make listenining initiation depend on its success
  const boost::function<void ()> initiateme =
      boost::bind(&PoolListener_t::initiateSocket, boost::ref(PoolListener));
  AsyncOperation *enrollOp = new EnrollInPoolOperation(connection_, MyAddress, initiateme, failed);
  LOG(2, "DEBUG: Putting enroll in pool operation into queue ...");
  OpQueue.push_back(enrollOp, ServerAddress);
}

/// Handle completion of a accept server operation.
void PoolWorker::PoolListener_t::handle_Accept(const boost::system::error_code& e, connection_ptr conn)
{
  Info info(__FUNCTION__);
  if (!e)
  {
    conn->async_read(job,
      boost::bind(&PoolWorker::PoolListener_t::handle_ReceiveJob, this,
      boost::asio::placeholders::error, conn));
    // and listen for following connections
    initiateSocket();
  }
  else
  {
    // An error occurred. Log it and return. Since we are not starting a new
    // accept operation the io_service will run out of work to do and the
    // server will exit.
    Exitflag = ErrorFlag;
    ELOG(0, e.message());
  }
}

/// Controller callback function when job has been sent.
void PoolWorker::PoolListener_t::handle_ReceiveJob(const boost::system::error_code& e, connection_ptr conn)
{
  Info info(__FUNCTION__);

  if (!e)
  {
    if (job->getId() != JobId::NoJob) {
      LOG(1, "INFO: Working on job " << job->getId() << ".");
      callback.WorkOnJob(job);
    } else {
      LOG(1, "INFO: Received NoJob.");
      callback.shutdown();
    }
  }
  else
  {
    // An error occurred. Log it and return. Since we are not starting a new
    // accept operation the io_service will run out of work to do and the
    // server will exit.
    Exitflag = ErrorFlag;
    ELOG(0, e.message());
  }
}

/** Works on the given job and send the results.
 *
 * @param job job to work on
 */
void PoolWorker::WorkOnJob(FragmentJob::ptr &job)
{
  // work on job and create result
  LOG(2, "DEBUG: Beginning to work on " << job->getId() << ".");
  FragmentResult::ptr result = job->Work();
  LOG(2, "DEBUG: Setting result " << result->getId() << ".");

  AsyncOperation *submitOp = new SubmitResultOperation(connection_, MyAddress, AsyncOperation::NoOpCallback, failed);
  static_cast<SubmitResultOperation *>(submitOp)->setResult(result);

  // submit result
  LOG(2, "DEBUG: Putting send result operation into queue ...");
  OpQueue.push_back(submitOp, ServerAddress);
}

/** Wrapper function to allow use as signal handler.
 *
 * We remove us from server's pool and then just call \sa PoolWorker::shutdown().
 *
 * @param sig signal received
 */
void PoolWorker::shutdown(int sig)
{
  LOG(1, "INFO: Shutting down due to signal "+toString(sig)+".");

  shutdown();
}

/** Helper function to shutdown the worker properly.
 *
 * Note that we will use RemoveFromPoolOperation to unlist from server's pool.
 */
void PoolWorker::shutdown()
{
  // remove us from pool
  boost::function<void ()> closingdown = boost::bind(&PoolWorker::finish, this);
  AsyncOperation *removeOp = new RemoveFromPoolOperation(connection_, MyAddress, closingdown, failed);
  LOG(2, "DEBUG: Putting remove from pool operation into queue ...");
  OpQueue.push_back(removeOp, ServerAddress);
  // block queue such that io_service may stop
  OpQueue.block();
}

/** Helper function to close down listener and stop service.
 *
 * This is called after we have been removed from server's pool
 * We stop the io_service via its callback handler in case of success.
 */
void PoolWorker::finish()
{
  // somehow stop listener
  PoolListener.closeSocket();

  // finally, stop io_service
  io_service.stop();
}