/**
 * @file tests/multithreading/simple/models.hpp
 * @author The ARTIS Development Team
 * See the AUTHORS or Authors.txt file
 */

/*
 * ARTIS - the multimodeling and simulation environment
 * This file is a part of the ARTIS environment
 *
 * Copyright (C) 2013-2022 ULCO http://www.univ-littoral.fr
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef TESTS_MULTITHREADING_SIMPLE_MODELS_HPP
#define TESTS_MULTITHREADING_SIMPLE_MODELS_HPP

#include <artis-star/common/time/DoubleTime.hpp>
#include <artis-star/kernel/pdevs/Dynamics.hpp>
#include <random>
#include <iostream>

namespace artis {
namespace tests {
namespace multithreading {
namespace simple {

void delay()
{
  for (unsigned int i = 0; i < 1000; ++i) {
    std::vector<int> v;

    for (unsigned int j = 1000; j > 0; --j) {
      v.push_back(j);
    }
    std::sort(v.begin(), v.end());
  }
}

struct State
{
  enum values
  {
    STOP, UP, MAX, DOWN
  };
};

struct Vehicle
{
  unsigned int index;
  double v_max;
  double acceleration;
  State::values state;
  artis::common::DoubleTime::type next_time;
};

struct GeneratorParameters
{
  double v_max;
  double mean;
  double stddev;
  unsigned long seed;
};

class Generator
    : public artis::pdevs::Dynamics<artis::common::DoubleTime, Generator, GeneratorParameters>
{
public:
  struct outputs
  {
    enum values
    {
      OUT
    };
  };

  Generator(const std::string &name,
            const artis::pdevs::Context<artis::common::DoubleTime,
                                        Generator,
                                        GeneratorParameters> &context)
      :
      artis::pdevs::Dynamics<artis::common::DoubleTime, Generator, GeneratorParameters>(
          name, context),
      _v_max(context.parameters().v_max),
      _distribution(context.parameters().mean, context.parameters().stddev),
      _v_max_distribution(0.5, 1.),
      _port_distribution(0, 7)
  {
    _generator.seed(context.parameters().seed);

    output_ports({{outputs::OUT, "out_1"}});
    output_ports({{outputs::OUT + 1, "out_2"}});
    output_ports({{outputs::OUT + 2, "out_3"}});
    output_ports({{outputs::OUT + 3, "out_4"}});
    output_ports({{outputs::OUT + 4, "out_5"}});
    output_ports({{outputs::OUT + 5, "out_6"}});
    output_ports({{outputs::OUT + 6, "out_7"}});
    output_ports({{outputs::OUT + 7, "out_8"}});
  }

  ~Generator() override = default;

  void dint(const artis::common::DoubleTime::type &t) override
  {

//    std::cout << get_full_name() << " at " << t << " - dint" << std::endl;

    _last_time = t;
    _sigma = _distribution(_generator);
    _sigma = _sigma <= 0 ? 0.1 : _sigma;
    _next_v_max = _v_max * _v_max_distribution(_generator);
    _next_port = _port_distribution(_generator);
    ++_index;
  }

  void start(const artis::common::DoubleTime::type &t) override
  {

//    std::cout << get_full_name() << " at " << t << " - start" << std::endl;

    _last_time = t;
    _sigma = _distribution(_generator);
    _sigma = _sigma <= 0 ? 0.1 : _sigma;
    _next_v_max = _v_max * _v_max_distribution(_generator);
    _next_port = _port_distribution(_generator);
    _index = 1;
  }

  artis::common::DoubleTime::type
  ta(const artis::common::DoubleTime::type & /* t */) const override
  { return _sigma; }

  artis::common::event::Bag<artis::common::DoubleTime>
  lambda(const artis::common::DoubleTime::type &t) const override
  {
    artis::common::event::Bag<artis::common::DoubleTime> bag;

//    std::cout << get_full_name() << " at " << t << " - lambda" << std::endl;

    if (t > 0) {
      Vehicle vehicle = {_index, _next_v_max, 0.5, State::STOP, t};

      bag.push_back(
          artis::common::event::ExternalEvent<artis::common::DoubleTime>(
              outputs::OUT + _next_port, vehicle));
    }
    return bag;
  }

  common::DoubleTime::type
  lookahead(const common::DoubleTime::type & /* t */) const override
  {
    return _last_time + _sigma;
  }

private:
  // parameters
  double _v_max;

  // state
  artis::common::DoubleTime::type _sigma;
  artis::common::DoubleTime::type _last_time;
  std::default_random_engine _generator;
  std::normal_distribution<double> _distribution;
  std::uniform_real_distribution<double> _v_max_distribution;
  std::uniform_int_distribution<int> _port_distribution;
  double _next_v_max;
  int _next_port;
  unsigned int _index;
};

class Counter
    : public artis::pdevs::Dynamics<artis::common::DoubleTime, Counter>
{
public:
  struct inputs
  {
    enum values
    {
      IN
    };
  };

  struct vars
  {
    enum values
    {
      COUNTER
    };
  };

  Counter(const std::string &name,
          const artis::pdevs::Context<artis::common::DoubleTime, Counter> &context)
      :
      artis::pdevs::Dynamics<artis::common::DoubleTime, Counter>(name,
                                                                 context)
  {
    input_port({inputs::IN, "in"});
    observable({vars::COUNTER, "counter"});
  }

  ~Counter() override = default;

  void dext(const artis::common::DoubleTime::type & /* t */,
            const artis::common::DoubleTime::type & /* e */,
            const artis::common::event::Bag<artis::common::DoubleTime> &bag) override
  {

//    std::cout << get_full_name() << " at " << t << " - dext" << std::endl;

    _counter += bag.size();
  }

  void start(const artis::common::DoubleTime::type & /* t */) override
  {

//    std::cout << get_full_name() << " at " << t << " - start" << std::endl;

    _counter = 0;
  }

  artis::common::DoubleTime::type
  ta(const artis::common::DoubleTime::type & /* t */) const override
  {
    return artis::common::DoubleTime::infinity;
  }

  artis::common::event::Value observe(const artis::common::DoubleTime::type & /* t */,
          unsigned int index) const override
  {
    if (index == vars::COUNTER) {
      return _counter;
    } else {
      return artis::common::event::Value();
    }
  }

  common::DoubleTime::type lookahead(const common::DoubleTime::type & /* t */) const override
  {
    return common::DoubleTime::infinity;
  }

private:
  unsigned int _counter;
};

class Link :
    public artis::pdevs::Dynamics<common::DoubleTime, Link>
{
public :
  struct inputs
  {
    enum values
    {
      IN
    };
  };

  struct outputs
  {
    enum values
    {
      OUT
    };
  };

  Link(const std::string &name,
       const artis::pdevs::Context<common::DoubleTime, Link> &context)
      : artis::pdevs::Dynamics<common::DoubleTime, Link>(name, context)
  {
    input_port({inputs::IN, "in"});
    output_port({outputs::OUT, "out"});
  }

  ~ Link() override = default;

  void dint(const artis::common::DoubleTime::type &t) override
  {
//    delay();

//    std::cout << get_full_name() << " at " << t << " - dint" << std::endl;

    auto it = _vehicles.begin();

    while (it != _vehicles.end()) {
      if (it->next_time == t and it->state == State::STOP) {
        _vehicles.erase(it);
        it = _vehicles.begin();
      } else {
        ++it;
      }
    }
    for (auto &vehicle: _vehicles) {
      if (vehicle.next_time == t) {
        switch (vehicle.state) {
        case State::UP: {
          double duration = vehicle.v_max / vehicle.acceleration;
          double acceleration_distance = 0.5 * vehicle.acceleration * duration * duration;

          vehicle.state = State::MAX;
          vehicle.next_time = t + (_length - 2 * acceleration_distance) / vehicle.v_max;
          break;
        }
        case State::MAX: {
          vehicle.state = State::DOWN;
          vehicle.next_time = t + vehicle.v_max / vehicle.acceleration;
          break;
        }
        case State::DOWN: {
          vehicle.state = State::STOP;
          vehicle.next_time = t;
          break;
        }
        case State::STOP: {
          assert(false);
          break;
        }
        }
      }
    }
    update_sigma(t);
  }

  void dext(const artis::common::DoubleTime::type &t,
            const artis::common::DoubleTime::type & /* e */,
            const artis::common::event::Bag<artis::common::DoubleTime> &bag) override
  {

//    std::cout << get_full_name() << " at " << t << " - dext" << std::endl;

    std::for_each(bag.begin(), bag.end(),
                  [this, t](const common::event::ExternalEvent<common::DoubleTime> &event) {
                    if (event.on_port(inputs::IN)) {
                      Vehicle vehicle;

                      event.data()(vehicle);
                      vehicle.next_time = t + vehicle.v_max / vehicle.acceleration;
                      vehicle.state = State::UP;
                      _vehicles.push_back(vehicle);
                    }
                  });
    update_sigma(t);
  }

  artis::common::DoubleTime::type ta(const artis::common::DoubleTime::type & /* t */) const override
  { return _sigma; }

  artis::common::event::Bag<artis::common::DoubleTime>
  lambda(const artis::common::DoubleTime::type &t) const override
  {
    artis::common::event::Bag<artis::common::DoubleTime> bag;

//    std::cout << get_full_name() << " at " << t << " - lambda" << std::endl;

    for (auto vehicle: _vehicles) {
      if (vehicle.next_time == t and vehicle.state == State::STOP) {
        bag.push_back(
            artis::common::event::ExternalEvent<artis::common::DoubleTime>(
                outputs::OUT, vehicle));
      }
    }
    return bag;
  }

  void start(const artis::common::DoubleTime::type & /* t */) override
  {

//    std::cout << get_full_name() << " at " << t << " - start" << std::endl;

    _sigma = artis::common::DoubleTime::infinity;
  }

  common::DoubleTime::type lookahead(const common::DoubleTime::type &t) const override
  {
    double eot = artis::common::DoubleTime::infinity;

    for (auto vehicle: _vehicles) {
      double eot_i = artis::common::DoubleTime::infinity;

      if (vehicle.next_time == t and vehicle.state == State::STOP) {
        eot_i = t;
      } else if (vehicle.state == State::DOWN) {
        eot_i = vehicle.next_time;
      } else if (vehicle.state == State::MAX) {
        eot_i = vehicle.next_time + vehicle.v_max / vehicle.acceleration;
      } else if (vehicle.state == State::UP) {
        double duration = vehicle.v_max / vehicle.acceleration;
        double acceleration_distance = 0.5 * vehicle.acceleration * duration * duration;

        eot_i = vehicle.next_time
            + (_length - 2 * acceleration_distance) / vehicle.v_max
            + vehicle.v_max / vehicle.acceleration;
      }
      if (eot_i < eot) {
        eot = eot_i;
      }
    }
    return eot;
  }

private:
  void update_sigma(const artis::common::DoubleTime::type &t)
  {
    if (_vehicles.empty()) {
      _sigma = artis::common::DoubleTime::infinity;
    } else {
      _sigma = std::min_element(_vehicles.begin(), _vehicles.end(),
                                [](const Vehicle &e1, const Vehicle &e2) {
                                  return e1.next_time < e2.next_time;
                                })->next_time - t;
    }
  }

  const double _length = 500;

  std::deque<Vehicle> _vehicles;
  artis::common::DoubleTime::type _sigma;
};

}
}
}
} // namespace artis tests multithreading simple

#endif