/***********************************************************************
  Moses - factored phrase-based language decoder
  Copyright (C) 2011 University of Edinburgh

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 ***********************************************************************/

#pragma once
#ifndef moses_OutputCollector_h
#define moses_OutputCollector_h

#ifdef WITH_THREADS
#include <boost/thread/mutex.hpp>
#endif

#ifdef BOOST_HAS_PTHREADS
#include <pthread.h>
#endif

#include <iostream>
#include <map>
#include <ostream>
#include <fstream>
#include <string>
#include "Util.h"
#include "util/exception.hh"
namespace Moses
{
/**
* Makes sure output goes in the correct order when multi-threading
**/
class OutputCollector
{
public:
  OutputCollector(std::ostream* outStream= &std::cout,
                  std::ostream* debugStream=&std::cerr)
    : m_nextOutput(0)
    , m_outStream(outStream)
    , m_debugStream(debugStream)
    , m_isHoldingOutputStream(false)
    , m_isHoldingDebugStream(false) {}

  OutputCollector(std::string xout, std::string xerr = "")
    : m_nextOutput(0) {
    // TO DO open magic streams instead of regular ofstreams! [UG]

    if (xout == "/dev/stderr") {
      m_outStream = &std::cerr;
      m_isHoldingOutputStream = false;
    } else if (xout.size() && xout != "/dev/stdout" && xout != "-") {
      m_outStream = new std::ofstream(xout.c_str());
      UTIL_THROW_IF2(!m_outStream->good(), "Failed to open output file"
                     << xout);
      m_isHoldingOutputStream = true;
    } else {
      m_outStream = &std::cout;
      m_isHoldingOutputStream = false;
    }

    if (xerr == "/dev/stdout") {
      m_debugStream = &std::cout;
      m_isHoldingDebugStream = false;
    } else if (xerr.size() && xerr != "/dev/stderr") {
      m_debugStream = new std::ofstream(xerr.c_str());
      UTIL_THROW_IF2(!m_debugStream->good(), "Failed to open debug stream"
                     << xerr);
      m_isHoldingDebugStream = true;
    } else {
      m_debugStream = &std::cerr;
      m_isHoldingDebugStream = false;
    }
  }

  ~OutputCollector() {
    if (m_isHoldingOutputStream)
      delete m_outStream;
    if (m_isHoldingDebugStream)
      delete m_debugStream;
  }

  void HoldOutputStream() {
    m_isHoldingOutputStream = true;
  }

  void HoldDebugStream() {
    m_isHoldingDebugStream = true;
  }

  bool OutputIsCout() const {
    return (m_outStream == &std::cout);
  }

  /**
    * Write or cache the output, as appropriate.
    **/
  void Write(int sourceId,const std::string& output,const std::string& debug="") {
#ifdef WITH_THREADS
    boost::mutex::scoped_lock lock(m_mutex);
#endif
    if (sourceId == m_nextOutput) {
      //This is the one we were expecting
      *m_outStream << output << std::flush;
      *m_debugStream << debug << std::flush;
      ++m_nextOutput;
      //see if there's any more
      std::map<int,std::string>::iterator iter;
      while ((iter = m_outputs.find(m_nextOutput)) != m_outputs.end()) {
        *m_outStream << iter->second << std::flush;
        ++m_nextOutput;
        std::map<int,std::string>::iterator debugIter = m_debugs.find(iter->first);
        m_outputs.erase(iter);
        if (debugIter != m_debugs.end()) {
          *m_debugStream << debugIter->second << std::flush;
          m_debugs.erase(debugIter);
        }
      }
    } else {
      //save for later
      m_outputs[sourceId] = output;
      m_debugs[sourceId] = debug;
    }
  }


private:
  std::map<int,std::string> m_outputs;
  std::map<int,std::string> m_debugs;
  int m_nextOutput;
  std::ostream* m_outStream;
  std::ostream* m_debugStream;
  bool m_isHoldingOutputStream;
  bool m_isHoldingDebugStream;
#ifdef WITH_THREADS
  boost::mutex m_mutex;
#endif

public:
  void SetOutputStream(std::ostream* outStream) {
    m_outStream = outStream;
  }

};

}  // namespace Moses

#endif