#include "AdaptInstationary.h"
#include "Parameters.h"
#include "Estimator.h"
#include "TecPlotWriter.h"
#include "ProblemIterationInterface.h"
#include "ProblemTimeInterface.h"
#include "Serializer.h"

namespace AMDiS {

  AdaptInstationary::AdaptInstationary(const char *name,
				       ProblemIterationInterface *problemStat,  
				       AdaptInfo *info,
				       ProblemTimeInterface *problemInstat,
				       AdaptInfo *initialInfo,
				       time_t initialTimestamp)
    : AdaptBase(name, problemStat, info, problemInstat, initialInfo),
      breakWhenStable(0)
  {
    FUNCNAME("AdaptInstationary::AdaptInstationary()");

    initialize(name_);

    fixedTimestep_ = (info->getMinTimestep() == info->getMaxTimestep());

    if (initialTimestamp == 0) {
      initialTimestamp_ = time(NULL);
    } else {
      initialTimestamp_ = initialTimestamp;
    }

    // Check if the problem should be deserialized because of the -rs parameter.
    std::string serializationFilename = "";
    GET_PARAMETER(0, "argv->rs", &serializationFilename);

    if (serializationFilename.compare("")) {
      // The value of the -rs argument is ignored, because we want to use the 
      // serialization file mentioned in the used init file.
      MSG("Deserialization from file: %s\n", queueSerializationFilename_.c_str());

      std::ifstream in(queueSerializationFilename_.c_str());
      deserialize(in);
      in.close();

      info->setIsDeserialized(true);
      initialInfo->setIsDeserialized(true);
    } else {
      int readSerialization = 0;
      int readSerializationWithAdaptInfo = 0;

      GET_PARAMETER(0, (*problemStat).getName() + "->input->read serialization", "%d", 
		    &readSerialization);
      GET_PARAMETER(0, (*problemStat).getName() + "->input->serialization with adaptinfo", "%d",
		    &readSerializationWithAdaptInfo);

      if (readSerialization && readSerializationWithAdaptInfo) {
	std::string serializationFilename = "";

	GET_PARAMETER(0, (*problemStat).getName() + "->input->serialization filename", 
		      &serializationFilename);
	TEST_EXIT(serializationFilename != "")("no serialization file\n");

	MSG("Deserialization with AdaptInfo from file: %s\n", serializationFilename.c_str());
	std::ifstream in(serializationFilename.c_str());
	deserialize(in);
	in.close();
      }
    }
  }

  AdaptInstationary::~AdaptInstationary()
  {
  }

  void AdaptInstationary::explicitTimeStrategy()
  {
    FUNCNAME("AdaptInstationary::explicitTimeStrategy()");

    // estimate before first adaption
    if (adaptInfo_->getTime() <= adaptInfo_->getStartTime()) {
      problemIteration_->oneIteration(adaptInfo_, ESTIMATE);
    }

    // increment time
    adaptInfo_->setTime(adaptInfo_->getTime() + adaptInfo_->getTimestep());

    problemTime_->setTime(adaptInfo_);

    INFO(info_,6)("time = %e, timestep = %e\n",
		  adaptInfo_->getTime(), adaptInfo_->getTimestep());

    adaptInfo_->setSpaceIteration(0);
  
    // do the iteration
    problemIteration_->beginIteration(adaptInfo_);
    problemIteration_->oneIteration(adaptInfo_, FULL_ITERATION);
    problemIteration_->endIteration(adaptInfo_);
  }

  void AdaptInstationary::implicitTimeStrategy()
  {
    FUNCNAME("AdaptInstationary::implicitTimeStrategy()");

    do {
      adaptInfo_->setTime(adaptInfo_->getTime() + adaptInfo_->getTimestep());
      problemTime_->setTime(adaptInfo_);

      INFO(info_,6)("time = %e, try timestep = %e\n",
		    adaptInfo_->getTime(), adaptInfo_->getTimestep());
    
      problemIteration_->oneIteration(adaptInfo_, NO_ADAPTION);

      adaptInfo_->incTimestepIteration();

      if (!fixedTimestep_ && 
	  !adaptInfo_->timeToleranceReached() &&
	  !adaptInfo_->getTimestep() <= adaptInfo_->getMinTimestep()) {

	adaptInfo_->setTime(adaptInfo_->getTime() - adaptInfo_->getTimestep());
	adaptInfo_->setTimestep(adaptInfo_->getTimestep() * time_delta_1);
	continue;
      }

      adaptInfo_->setSpaceIteration(0);


      /* === Do only space iterations only if the maximum is higher than 0. === */

      if (adaptInfo_->getMaxSpaceIteration() > 0) {
    
	/* === Space iterations === */
	do {
	  problemIteration_->beginIteration(adaptInfo_);
	  
	  if (problemIteration_->oneIteration(adaptInfo_, FULL_ITERATION)) {
	    if (!fixedTimestep_ && 
		!adaptInfo_->timeToleranceReached() &&
		!adaptInfo_->getTimestep() <= adaptInfo_->getMinTimestep()) 
	      {
		adaptInfo_->setTime(adaptInfo_->getTime() - adaptInfo_->getTimestep());
		adaptInfo_->setTimestep(adaptInfo_->getTimestep() * time_delta_1);
		problemIteration_->endIteration(adaptInfo_);
		adaptInfo_->incSpaceIteration();
		break;
	      }	
	  }

	  adaptInfo_->incSpaceIteration();
	  problemIteration_->endIteration(adaptInfo_);
	  
	} while(!adaptInfo_->spaceToleranceReached() && 
		adaptInfo_->getSpaceIteration() <= adaptInfo_->getMaxSpaceIteration());

      } else {
	problemIteration_->endIteration(adaptInfo_);
      }


    } while(!adaptInfo_->timeToleranceReached() &&
	    !adaptInfo_->getTimestep() <= adaptInfo_->getMinTimestep() && 
	    adaptInfo_->getTimestepIteration() <= adaptInfo_->getMaxTimestepIteration());  

    if (!fixedTimestep_ && adaptInfo_->timeErrorLow()) {
      adaptInfo_->setTimestep(adaptInfo_->getTimestep() *time_delta_2);
    }
  }

  void AdaptInstationary::oneTimestep()
  {
    FUNCNAME("AdaptInstationary::oneTimestep");

    adaptInfo_->setTimestepIteration(0);

    switch(strategy)
      {
      case 0:
	explicitTimeStrategy();
	break;
      case 1:
	implicitTimeStrategy();
	break;
      default:
	MSG("unknown strategy = %d; use explicit strategy\n", strategy);
	explicitTimeStrategy();
      }

    adaptInfo_->incTimestepNumber();
  }

  int AdaptInstationary::adapt()
  {
    FUNCNAME("AdaptInstationary::adapt()");

    int errorCode = 0;

    TEST_EXIT(adaptInfo_->getTimestep() >= adaptInfo_->getMinTimestep())
      ("timestep < min timestep\n");
    TEST_EXIT(adaptInfo_->getTimestep() <= adaptInfo_->getMaxTimestep())
      ("timestep > max timestep\n");

    TEST_EXIT(adaptInfo_->getTimestep() > 0)("timestep <= 0!\n");

    if (adaptInfo_->getTimestepNumber() == 0) {
      adaptInfo_->setTime(adaptInfo_->getStartTime());
      initialAdaptInfo_->setStartTime(adaptInfo_->getStartTime());
      initialAdaptInfo_->setTime(adaptInfo_->getStartTime());

      problemTime_->setTime(adaptInfo_);

      // initial adaption
      problemTime_->solveInitialProblem(initialAdaptInfo_);
      problemTime_->transferInitialSolution(adaptInfo_);
    }

    while (adaptInfo_->getTime() < adaptInfo_->getEndTime() - DBL_TOL) {
      iterationTimestamp_ = time(NULL);

      problemTime_->initTimestep(adaptInfo_);

      oneTimestep();

      problemTime_->closeTimestep(adaptInfo_);

      if (breakWhenStable && (adaptInfo_->getSolverIterations() == 0)) {
	break;
      }

      // Check if there is a runtime limitation. If there is a runtime limitation
      // and there is no more time for a next adaption loop, than return the error
      // code for rescheduling the problem and break the adaption loop.
      if (checkQueueRuntime()) {
	errorCode = RescheduleErrorCode;
	break;
      }
    }

    return errorCode;
  }

  void AdaptInstationary::initialize(const std::string& aName)
  {
    FUNCNAME("AdaptInstationary::initialize()");

    strategy = 0;
    time_delta_1 = 0.7071;
    time_delta_2 = 1.4142;
    queueRuntime_ = -1;
    queueSerializationFilename_ = "__serialized_problem.ser";

    GET_PARAMETER(0, aName + "->strategy", "%d", &strategy);
    GET_PARAMETER(0, aName + "->time delta 1", "%f", &time_delta_1);
    GET_PARAMETER(0, aName + "->time delta 2", "%f", &time_delta_2);
    GET_PARAMETER(0, aName + "->info", "%d", &info_);
    GET_PARAMETER(0, aName + "->break when stable", "%d", &breakWhenStable);
    GET_PARAMETER(0, aName + "->queue->runtime", "%d", &queueRuntime_);
    GET_PARAMETER(0, aName + "->queue->serialization filename", &queueSerializationFilename_);

    return;
  }

  void AdaptInstationary::serialize(std::ostream &out)
  {
    FUNCNAME("AdaptInstationary::serialize()");

    problemIteration_->serialize(out);
    adaptInfo_->serialize(out);
    if (problemTime_) {
      problemTime_->serialize(out);
    }
  }

  void AdaptInstationary::deserialize(std::istream &in)
  {
    FUNCNAME("AdaptInstationary::deserialize()");

    problemIteration_->deserialize(in);
    adaptInfo_->deserialize(in);
    if (problemTime_) {
      problemTime_->deserialize(in);
    }
  }


  bool AdaptInstationary::checkQueueRuntime()
  {
    // If there is no time limited runtime queue, there is also nothing to check.
    if (queueRuntime_ == -1) {
      return false;
    }

    // Get the current time.
    time_t currentTimestamp = time(NULL);

    // Update list with the last iteration runtimes.
    lastIterationsDuration_.push(currentTimestamp - iterationTimestamp_);
    // The list should not contain more than 5 elements. If so, delete the oldest one.
    if (lastIterationsDuration_.size() > 5) {
      lastIterationsDuration_.pop();
    }

    // Calculate the avarage of the last iterations.
    std::queue<int> tmpQueue = lastIterationsDuration_;
    int avrgLastIterations = 0;
    while (!tmpQueue.empty()) {
      avrgLastIterations += tmpQueue.front();
      tmpQueue.pop();
    } 
    avrgLastIterations /= lastIterationsDuration_.size();
    
    // Check if there is enough time for a further iteration.
    if (initialTimestamp_ + queueRuntime_ - currentTimestamp < avrgLastIterations * 2) {
      std::ofstream out(queueSerializationFilename_.c_str());
      serialize(out);
      out.close();

      return true;
    }

    return false;
  }

}