/**
 * @file utils/Trace.hpp
 * @author See the AUTHORS file
 */

/*
 * Copyright (C) 2012-2019 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 UTILS_TRACE
#define UTILS_TRACE

#include <algorithm>
#include <iterator>
#include <memory>
#include <mutex>
#include <sstream>
#include <string>
#include <vector>

#include <artis/utils/DateTime.hpp>

namespace artis {
    namespace utils {

        enum TraceType {
            NONE = 0, CHECK, COMPUTE, INIT, KERNEL, PUT
        };

        template<class Time>
        class TraceElement {
        public:
            TraceElement()
                    :_time(Time::null), _type(NONE) { }

            TraceElement(const std::string& model_name, typename Time::type time,
                    TraceType type)
                    :
                    _model_name(model_name), _time(time), _type(type) { }

            virtual ~TraceElement() { }

            const std::string& get_comment() const { return _comment; }

            const std::string& get_model_name() const { return _model_name; }

            typename Time::type get_time() const { return _time; }

            TraceType get_type() const { return _type; }

            void set_comment(const std::string& comment) { _comment = comment; }

        private:
            std::string _model_name;
            typename Time::type _time;
            TraceType _type;
            std::string _comment;
        };

        template<class Time>
        class TraceElements : public std::vector<TraceElement<Time> > {
        public:
            TraceElements() { }

            virtual ~TraceElements() { }

            TraceElements filter_model_name(
                    const std::string& model_name) const
            {
                TraceElements<Time> result;

                std::copy_if(TraceElements<Time>::begin(),
                        TraceElements<Time>::end(), std::back_inserter(result),
                        [model_name](TraceElement<Time> const& x) { return x.get_model_name() == model_name; });
                return result;
            }

            TraceElements filter_time(typename Time::type time) const
            {
                TraceElements result;

                std::copy_if(TraceElements<Time>::begin(),
                        TraceElements<Time>::end(), std::back_inserter(result),
                        [time](TraceElement<Time> const& x) { return x.get_time() == time; });
                return result;
            }

            TraceElements filter_type(TraceType type) const
            {
                TraceElements result;

                std::copy_if(TraceElements<Time>::begin(),
                        TraceElements<Time>::end(), std::back_inserter(result),
                        [type](TraceElement<Time> const& x) { return x.get_type() == type; });
                return result;
            }

            std::string to_string() const
            {
                std::ostringstream ss;

                for (typename TraceElements<Time>::const_iterator it =
                        TraceElements<Time>::begin();
                     it != TraceElements<Time>::end(); ++it) {
                    ss << "TRACE: " << it->get_model_name() << " at "
                       << utils::DateTime::toJulianDay(it->get_time()) << " <";
                    switch (it->get_type()) {
                    case NONE:
                        ss << "none";
                        break;
                    case CHECK:
                        ss << "check";
                        break;
                    case COMPUTE:
                        ss << "compute";
                        break;
                    case INIT:
                        ss << "init";
                        break;
                    case KERNEL:
                        ss << "kernel";
                        break;
                    case PUT:
                        ss << "put";
                        break;
                    };
                    ss << ">";
                    if (not it->get_comment().empty()) {
                        ss << " => " << it->get_comment();
                    }
                    ss << std::endl;
                }
                return ss.str();
            }
        };

        template<class Time>
        class Trace {
        public:
            virtual ~Trace() { }

            static Trace& trace()
            {
                std::call_once(_flag, []() { _instance.reset(new Trace()); }
                );
                return *_instance;
            }

            void clear() { _trace.clear(); }

            const TraceElements<Time>& elements() const { return _trace; }

            void flush()
            {
                if (_sstream) {
                    _element.set_comment(_sstream->str());
                    delete _sstream;
                    _sstream = 0;
                }
                _trace.push_back(_element);
            }

            std::mutex& mutex() { return _mutex; }

            void set_element(const TraceElement<Time>& element) { _element = element; }

            std::ostringstream& sstream()
            {
                if (_sstream == 0) {
                    _sstream = new std::ostringstream();
                }
                return *_sstream;
            }

        private:
            Trace() { _sstream = 0; }

            static std::shared_ptr<Trace<Time> > _instance;
            static std::once_flag _flag;

            TraceElements<Time> _trace;
            TraceElement<Time> _element;
            std::ostringstream* _sstream;
            std::mutex _mutex;
        };

    }
}

template<class Time>
artis::utils::Trace<Time>& operator<<(
        artis::utils::Trace<Time>& trace,
        const artis::utils::TraceElement<Time>& e)
{
    std::lock_guard<std::mutex> lock(trace.mutex());

    trace.set_element(e);
    return trace;
}

template<class Time>
artis::utils::Trace<Time>& operator<<(
        artis::utils::Trace<Time>& trace,
        const std::string& str)
{
    std::lock_guard<std::mutex> lock(trace.mutex());

    trace.sstream() << str;
    return trace;
}

template<class Time>
artis::utils::Trace<Time>& operator<<(
        artis::utils::Trace<Time>& trace,
        typename Time::type t)
{
    std::lock_guard<std::mutex> lock(trace.mutex());

    trace.sstream() << t;
    return trace;
}

template<class Time>
std::shared_ptr<artis::utils::Trace<Time> >
        artis::utils::Trace<Time>::_instance;

template<class Time>
std::once_flag artis::utils::Trace<Time>::_flag;

#endif