/**
 * @file kernel/pdevs/multithreading/Coordinator.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) 2013-2019 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 PDEVS_MULTITHREADING_COORDINATOR
#define PDEVS_MULTITHREADING_COORDINATOR 1

#include <artis-star/common/utils/Multithreading.hpp>
#include <artis-star/kernel/pdevs/Coordinator.hpp>

#include <thread>

namespace artis {
    namespace pdevs {
        namespace multithreading {

            template<class Time>
            struct start_message {
                explicit start_message(typename Time::type t)
                        :_t(t) { }

                typename Time::type _t;
            };

            template<class Time>
            struct transition_message {
                explicit transition_message(typename Time::type t)
                        :_t(t) { }

                typename Time::type _t;
            };

            template<class Time>
            struct done_start_message {
                explicit done_start_message(typename Time::type tn,
                        common::Model<Time>* child)
                        :
                        _tn(tn), _child(child) { }

                typename Time::type _tn;
                common::Model<Time>* _child;
            };

            template<class Time>
            struct done_transition_message {
                explicit done_transition_message(typename Time::type tn,
                        common::Model<Time>* child)
                        :
                        _tn(tn), _child(child) { }

                typename Time::type _tn;
                common::Model<Time>* _child;
            };

            template<class Time,
                    class GraphManager,
                    class Parameters = common::NoParameters,
                    class GraphParameters = common::NoParameters>
            class Coordinator : public pdevs::Coordinator<Time, GraphManager, Parameters, GraphParameters> {
                typedef pdevs::Coordinator<Time, GraphManager,
                        Parameters, GraphParameters> parent_type;
                typedef Coordinator<Time, GraphManager,
                        Parameters, GraphParameters> type;
                typedef done_start_message<Time> done_start_message_type;
                typedef start_message<Time> start_message_type;
                typedef done_transition_message<Time> done_transition_message_type;
                typedef transition_message<Time> transition_message_type;

            public:
                Coordinator(const std::string& name, const Parameters& parameters,
                        const GraphParameters& graph_parameters)
                        :
                        common::Model<Time>(name),
                        pdevs::Coordinator<Time, GraphManager, Parameters, GraphParameters>(
                                name, parameters, graph_parameters)
                {
                    type::_graph_manager.init();
                    _thread = new std::thread([&] { loop(); });
                }

                virtual ~Coordinator()
                {
                    done();
                    _thread->join();
                    delete _thread;
                }

                void done() { get_sender().send(artis::common::Close()); }

                artis::common::Sender get_sender() { return _incoming; }

                void set_sender(common::Sender sender) { _sender = sender; }

                void loop()
                {
                    try {
                        for (;;) {
                            _incoming.wait()
                                    .template handle<start_message_type>(
                                            [&](start_message_type const& msg) {
                                                typename Time::type tn = start(msg._t);
                                                _sender.send(done_start_message_type(tn, this));
                                            })
                                    .
                                            template handle<done_start_message_type>(
                                            [&](done_start_message_type const& msg) {
                                                type::_event_table.init(msg._tn, msg._child);
                                                --_received;
                                                if (_received == 0) {
                                                    _received_mutex.unlock();
                                                }
                                            })
                                    .
                                            template handle<transition_message_type>(
                                            [&](transition_message_type const& msg) {
                                                typename Time::type tn = transition(msg._t);
                                                _sender.send(done_transition_message_type(tn,
                                                        this));
                                            })
                                    .
                                            template handle<done_transition_message_type>(
                                            [&](done_transition_message_type const& msg) {
                                                type::_event_table.put(msg._tn, msg._child);
                                                --_received;
                                                if (_received == 0) {
                                                    _received_mutex.unlock();
                                                }
                                            });
                        }
                    }
                    catch (artis::common::Close const&) { }
                }

                typename Time::type start(const typename Time::type& t)
                {
                    _received = 0;
                    for (auto& child : parent_type::_graph_manager.children()) {
                        if (child->is_atomic()) {
                            type::_event_table.init(child->start(type::_tn), child);
                        } else {
                            ++_received;
                        }
                    }

                    if (_received > 0) {
                        _received_mutex.lock();
                        type::_graph_manager.start(t);

                        std::lock_guard<std::mutex> lock(_received_mutex);
                    }

                    type::_tl = t;
                    type::_tn = type::_event_table.get_current_time();
                    return type::_tn;
                }

                // TODO: to remove
                virtual int get_receiver_number(typename Time::type t)
                {
                    return type::_event_table.get_current_models(t).size();
                }

                typename Time::type transition(const typename Time::type& t)
                {
                    assert(t >= type::_tl and t <= type::_tn);

                    common::Models<Time> receivers = type::get_receivers();
                    common::Models<Time> IMM = type::_event_table.get_current_models(t);

                    _received = 0;
                    for (auto& model : receivers) {
                        if (model->is_atomic()) {
                            type::_event_table.put(model->transition(t), model);
                        } else {
                            ++_received;
                        }
                    }
                    for (auto& model : IMM) {
                        if (std::find(receivers.begin(), receivers.end(),
                                model) == receivers.end()) {
                            if (model->is_atomic()) {
                                type::_event_table.put(model->transition(t), model);
                            } else {
                                ++_received;
                            }
                        }
                    }

                    if (_received > 0) {
                        _received_mutex.lock();
                        type::_graph_manager.transition(receivers, t);

                        std::lock_guard<std::mutex> lock(_received_mutex);
                    }

                    parent_type::update_event_table(t);
                    type::_tl = t;
                    type::_tn = type::_event_table.get_current_time();
                    type::clear_bag();

                    return type::_tn;
                }

            private:
                std::thread* _thread;
                artis::common::Receiver _incoming;
                artis::common::Sender _sender;
                unsigned int _received;
                std::mutex _received_mutex;
            };

        }
    }
} // namespace artis pdevs multithreading

#endif