/**
 * @file utils/RootStateMachine.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) 2013-2023 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 ARTIS_STAR_ADDONS_UTILS_ROOT_STATE_MACHINE_HPP
#define ARTIS_STAR_ADDONS_UTILS_ROOT_STATE_MACHINE_HPP

#include <artis-star-addons/utils/StateMachine.hpp>

#include <memory>
#include <vector>

namespace artis::addons::utils {

template<class Time, class Types, class Parameters, class StateMachineTypes>
class RootStateMachine {
public:
  typedef std::vector<typename Types::state_machine_type::ExternalEvent> external_events_type;

  RootStateMachine() = default;

  virtual ~RootStateMachine() = default;

  virtual void build(const Parameters &parameters) = 0;

  template<class RootStateMachineType, size_t N>
  constexpr void build_machines(const Parameters &parameters) {
    if constexpr(N == 1)
    {
      this->template build_machine<RootStateMachineType, std::tuple_element_t < 0, StateMachineTypes>>
      (0, parameters);
    } else {
      this->template build_machine<RootStateMachineType, std::tuple_element_t < N - 1, StateMachineTypes>>
      (N - 1, parameters);
      build_machines<RootStateMachineType, N - 1>(parameters);
    }
  }

  int current_state(int machine_id) const {
    typename Types::state_machine_IDs_type::values key =
      static_cast<typename Types::state_machine_IDs_type::values>(machine_id);

    return _machines.find(key)->second->current_state()->_id;
  }

  const std::shared_ptr<typename Types::state_machine_type> &
  machine(const int machine_id) {
    typename Types::state_machine_IDs_type::values key =
      static_cast<typename Types::state_machine_IDs_type::values>(machine_id);

    return _machines.find(key)->second;
  }

  const external_events_type &outbox() const { return _outbox; }

  void start(const typename Time::type &t) {
    std::for_each(_machines.begin(), _machines.end(), [t](const auto &e) {
      e.second->start(t);
    });
    _last_time = t;
  }

  template<class StateType>
  const StateType &state_(int machine_id) const {
    typename Types::state_machine_IDs_type::values key =
      static_cast<typename Types::state_machine_IDs_type::values>(machine_id);

    return std::dynamic_pointer_cast < StateMachine < Time, Types, StateType >> (_machines.at(key))->state_();
  }

  typename Time::type ta(const typename Time::type &t) const {
    if (_outbox.empty()) {
      typename Time::type min = Time::infinity;

      std::for_each(_machines.cbegin(), _machines.cend(), [t, &min](const auto &e) {
        typename Time::type ta = e.second->ta(t);

        min = min < ta ? min : ta;
      });
      return min;
    } else return 0;
  }

  void transition(const typename Time::type &t) {
    if (_outbox.empty()) {
      std::for_each(_machines.cbegin(), _machines.cend(), [t, this](const auto &e) {
        if (e.second->is_ready(t)) {
          typename Types::state_machine_type::Events events = e.second->transition(t);

          dispatch(t, events.internals);
          appendEvents(events.externals);
        }
      });
    } else {
      _outbox.clear();
    }
    _last_time = t;
    std::for_each(_machines.cbegin(), _machines.cend(), [t](const auto &e) {
      e.second->update_sigma(t);
    });
  }

  void transition(const typename Time::type &t, int machine_id,
                  const typename Types::state_machine_type::ExternalEvent &e) {
    typename Types::state_machine_IDs_type::values key =
      static_cast<typename Types::state_machine_IDs_type::values>(machine_id);
    typename Types::state_machine_type::Events events = _machines.at(key)->transition(t, e);

    dispatch(t, events.internals);
    appendEvents(events.externals);
    std::for_each(_machines.cbegin(), _machines.cend(), [t](const auto &e) {
      e.second->update_sigma(t);
    });
  }

protected:
  template<class RootStateMachineType, class FinalStateMachine>
  void build_machine(int machine_id, const Parameters &parameters) {
    auto machine = std::make_shared<FinalStateMachine>(*dynamic_cast<RootStateMachineType *>(this), parameters);
    typename Types::state_machine_IDs_type::values key =
      static_cast<typename Types::state_machine_IDs_type::values>(machine_id);

    machine->build(machine);
    this->_machines[key] = std::dynamic_pointer_cast<typename Types::state_machine_type>(machine);
  }

private:
  void appendEvents(const std::vector<typename Types::state_machine_type::ExternalEvent> &events) {
    _outbox.insert(_outbox.end(), events.cbegin(), events.cend());
  }

  void
  dispatch(const typename Time::type &t, const std::vector<typename Types::state_machine_type::InternalEvent> &events) {
    std::for_each(events.cbegin(), events.cend(),
                  [t, this](const auto &e) {
                    typename Types::state_machine_IDs_type::values key =
                      static_cast<typename Types::state_machine_IDs_type::values>(e.machine_id);
                    auto it = _machines.find(key);

                    if (it != _machines.end()) {
                      typename Types::state_machine_type::Events events = it->second->transition(t, e);

                      dispatch(t, events.internals);
                      appendEvents(events.externals);
                    }
                  });
  }

  std::map<typename Types::state_machine_IDs_type::values, std::shared_ptr<typename Types::state_machine_type>> _machines;

  external_events_type _outbox;
  typename Time::type _last_time{};
};

}

#endif //ARTIS_STAR_ADDONS_UTILS_ROOT_STATE_MACHINE_HPP