// This file is part of Bertini 2.
//
// trackers/observers.hpp is free software: you can redistribute it and/or
// modify it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
// trackers/observers.hpp 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with trackers/observers.hpp.  If not, see
// <http://www.gnu.org/licenses/>.
//
//  Copyright(C) 2015 - 2021 by Bertini2 Development Team
//
//  See <http://www.gnu.org/licenses/> for a copy of the license,
//  as well as COPYING.  Bertini2 is provided with permitted
//  additional terms in the b2/licenses/ directory.

// individual authors of this file include:
// silviana amethyst, university of wisconsin eau claire

/**
\file include/trackers/observers.hpp

\brief Contains the trackers/observers base types
*/

#pragma once

#include <boost/type_index.hpp>

#include "detail/observer.hpp"
#include "logging.hpp"
#include "trackers/base_tracker.hpp"
#include "trackers/events.hpp"

namespace bertini {

namespace tracking {

template <class TrackerT>
class FirstPrecisionRecorder : public Observer<TrackerT> {
  BOOST_TYPE_INDEX_REGISTER_CLASS

  using EmitterT = typename TrackerTraits<TrackerT>::EventEmitterType;

  virtual void Observe(AnyEvent const& e) override {
    if (auto p = dynamic_cast<const TrackingStarted<EmitterT>*>(&e)) {
      precision_increased_ = false;
      starting_precision_ = p->Get().CurrentPrecision();
    } else if (auto p = dynamic_cast<const PrecisionChanged<EmitterT>*>(&e)) {
      auto& t = p->Get();
      auto next = p->Next();
      if (next > p->Previous()) {
        precision_increased_ = true;
        next_precision_ = next;
        time_of_first_increase_ = t.CurrentTime();
        t.RemoveObserver(*this);
      }
    }
  }

 public:
  unsigned StartPrecision() const { return starting_precision_; }

  unsigned NextPrecision() const { return next_precision_; }

  bool DidPrecisionIncrease() const { return precision_increased_; }

  typename TrackerTraits<TrackerT>::BaseComplexType TimeOfIncrease() const {
    return time_of_first_increase_;
  }

  virtual ~FirstPrecisionRecorder() = default;

 private:
  unsigned starting_precision_;
  unsigned next_precision_;
  bool precision_increased_;
  typename TrackerTraits<TrackerT>::BaseComplexType time_of_first_increase_;
};

template <class TrackerT>
class MinMaxPrecisionRecorder : public Observer<TrackerT> {
  BOOST_TYPE_INDEX_REGISTER_CLASS

  using EmitterT = typename TrackerTraits<TrackerT>::EventEmitterType;

  virtual void Observe(AnyEvent const& e) override {
    if (auto p = dynamic_cast<const PrecisionChanged<EmitterT>*>(&e)) {
      auto next_precision = p->Next();
      if (next_precision < min_precision_) min_precision_ = next_precision;
      if (next_precision > max_precision_) max_precision_ = next_precision;
    } else if (auto p = dynamic_cast<const TrackingStarted<EmitterT>*>(&e)) {
      min_precision_ = p->Get().CurrentPrecision();
      max_precision_ = p->Get().CurrentPrecision();
    }
  }

 public:
  unsigned MinPrecision() const { return min_precision_; }

  unsigned MaxPrecision() const { return max_precision_; }

  void MinPrecision(unsigned m) { min_precision_ = m; }

  void MaxPrecision(unsigned m) { max_precision_ = m; }

  virtual ~MinMaxPrecisionRecorder() = default;

 private:
  unsigned min_precision_ = std::numeric_limits<unsigned>::max();
  unsigned max_precision_ = 0;
};

template <class TrackerT>
class PrecisionAccumulator : public Observer<TrackerT> {
  BOOST_TYPE_INDEX_REGISTER_CLASS

  using EmitterT = typename TrackerTraits<TrackerT>::EventEmitterType;

  virtual void Observe(AnyEvent const& e) override {
    const TrackingEvent<EmitterT>* p =
        dynamic_cast<const TrackingEvent<EmitterT>*>(&e);
    if (p) {
      precisions_.push_back(p->Get().CurrentPrecision());
    }
  }

 public:
  const std::vector<unsigned>& Precisions() const { return precisions_; }

  virtual ~PrecisionAccumulator() = default;

 private:
  std::vector<unsigned> precisions_;
};

/**
Example usage:
PathAccumulator<AMPTracker> path_accumulator;
*/
template <class TrackerT, template <class> class EventT = SuccessfulStep>
class AMPPathAccumulator : public Observer<TrackerT> {
  BOOST_TYPE_INDEX_REGISTER_CLASS

  using EmitterT = typename TrackerTraits<TrackerT>::EventEmitterType;

  virtual void Observe(AnyEvent const& e) override {
    const EventT<EmitterT>* p = dynamic_cast<const EventT<EmitterT>*>(&e);
    if (p) {
      path_.push_back(p->Get().CurrentPoint());
    }
  }

 public:
  const std::vector<Vec<mpfr_complex> >& Path() const { return path_; }

  virtual ~AMPPathAccumulator() = default;

 private:
  std::vector<Vec<mpfr_complex> > path_;
};

template <class TrackerT>
class GoryDetailLogger : public Observer<TrackerT> {
  BOOST_TYPE_INDEX_REGISTER_CLASS
 public:
  using EmitterT = typename TrackerTraits<TrackerT>::EventEmitterType;

  virtual ~GoryDetailLogger() = default;

  virtual void Observe(AnyEvent const& e) override {
    if (auto p = dynamic_cast<const Initializing<EmitterT, dbl>*>(&e)) {
      BOOST_LOG_TRIVIAL(severity_level::debug)
          << std::setprecision(p->Get().GetSystem().precision())
          << "initializing in double, tracking path\nfrom\tt = "
          << p->StartTime() << "\nto\tt = " << p->EndTime() << "\n from\tx = \n"
          << p->StartPoint() << "\n tracking system " << p->Get().GetSystem()
          << "\n\n";
    } else if (auto p =
                   dynamic_cast<const Initializing<EmitterT, mpfr_complex>*>(
                       &e)) {
      BOOST_LOG_TRIVIAL(severity_level::debug)
          << std::setprecision(p->Get().GetSystem().precision())
          << "initializing in multiprecision, tracking path\nfrom\tt = "
          << p->StartTime() << "\nto\tt = " << p->EndTime() << "\n from\tx = \n"
          << p->StartPoint() << "\n tracking system " << p->Get().GetSystem()
          << "\n\n";
    }

    else if (auto p = dynamic_cast<const TrackingEnded<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace) << "tracking ended";

    else if (auto p = dynamic_cast<const NewStep<EmitterT>*>(&e)) {
      auto& t = p->Get();
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "Tracker iteration " << t.NumTotalStepsTaken()
          << "\ncurrent precision: " << t.CurrentPrecision();

      BOOST_LOG_TRIVIAL(severity_level::trace)
          << std::setprecision(t.CurrentPrecision())
          << "t = " << t.CurrentTime()
          << "\ncurrent stepsize: " << t.CurrentStepsize()
          << "\ndelta_t = " << t.DeltaT()
          << "\ncurrent x size = " << t.CurrentPoint().size()
          << "\ncurrent x = " << t.CurrentPoint();
    }

    else if (auto p = dynamic_cast<const SingularStartPoint<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace) << "singular start point";
    else if (auto p = dynamic_cast<const InfinitePathTruncation<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "tracker iteration indicated going to infinity, truncated path";

    else if (auto p = dynamic_cast<const SuccessfulStep<EmitterT>*>(&e)) {
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "tracker iteration successful\n\n\n";
    }

    else if (auto p = dynamic_cast<const FailedStep<EmitterT>*>(&e)) {
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "tracker iteration unsuccessful\n\n\n";
    }

    else if (auto p =
                 dynamic_cast<const SuccessfulPredict<EmitterT, mpfr_complex>*>(
                     &e)) {
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << std::setprecision(Precision(p->ResultingPoint()))
          << "prediction successful (mpfr_complex), result:\n"
          << p->ResultingPoint();
    } else if (auto p =
                   dynamic_cast<const SuccessfulPredict<EmitterT, dbl>*>(&e)) {
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << std::setprecision(Precision(p->ResultingPoint()))
          << "prediction successful (dbl), result:\n"
          << p->ResultingPoint();
    }

    else if (auto p =
                 dynamic_cast<const SuccessfulCorrect<EmitterT, mpfr_complex>*>(
                     &e)) {
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << std::setprecision(Precision(p->ResultingPoint()))
          << "correction successful (mpfr_complex), result:\n"
          << p->ResultingPoint();
    } else if (auto p =
                   dynamic_cast<const SuccessfulCorrect<EmitterT, dbl>*>(&e)) {
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << std::setprecision(Precision(p->ResultingPoint()))
          << "correction successful (dbl), result:\n"
          << p->ResultingPoint();
    }

    else if (auto p = dynamic_cast<
                 const PredictorHigherPrecisionNecessary<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "Predictor, higher precision necessary";
    else if (auto p = dynamic_cast<
                 const CorrectorHigherPrecisionNecessary<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "corrector, higher precision necessary";

    else if (auto p =
                 dynamic_cast<const CorrectorMatrixSolveFailure<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "corrector, matrix solve failure or failure to converge";
    else if (auto p =
                 dynamic_cast<const PredictorMatrixSolveFailure<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "predictor, matrix solve failure or failure to converge";
    else if (auto p = dynamic_cast<
                 const FirstStepPredictorMatrixSolveFailure<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::trace)
          << "Predictor, matrix solve failure in initial solve of prediction";

    else if (auto p = dynamic_cast<const PrecisionChanged<EmitterT>*>(&e))
      BOOST_LOG_TRIVIAL(severity_level::debug)
          << "changing precision from " << p->Previous() << " to " << p->Next();

    else
      BOOST_LOG_TRIVIAL(severity_level::debug)
          << "unlogged event, of type: "
          << boost::typeindex::type_id_runtime(e).pretty_name();
  }
};

template <class TrackerT>
class StepFailScreenPrinter : public Observer<TrackerT> {
  BOOST_TYPE_INDEX_REGISTER_CLASS
 public:
  using EmitterT = typename TrackerTraits<TrackerT>::EventEmitterType;

  virtual void Observe(AnyEvent const& e) override {
    if (auto p = dynamic_cast<const FailedStep<EmitterT>*>(&e))
      std::cout << "observed step failure" << std::endl;
  }

  virtual ~StepFailScreenPrinter() = default;
};

}  // namespace tracking

}  // namespace bertini