/*
  *  MoMEMta: a modular implementation of the Matrix Element Method
  *  Copyright (C) 2016  Universite catholique de Louvain (UCL), Belgium
  *
  *  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/>.
  */
 
 // Heavily inspired by spdlog, Copyright(c) 2015 Gabi Melman
 
 #pragma once
 
 #include <momemta/impl/logger/common.h>
 #include <momemta/impl/logger/formatter.h>
 #include <momemta/impl/logger/sink.h>
 
 #include <sstream>
 #include <vector>
 
 namespace logger {
 
 class logger {
 public:
     logger(sink_ptr single_sink);
 
     virtual ~logger();
     logger(const logger&) = delete;
     logger& operator=(const logger&) = delete;
 
     bool should_log(logging::level::level_enum) const;
     void set_level(logging::level::level_enum);
     logging::level::level_enum level() const;
 
     void set_formatter(formatter_ptr);
 
     // automatically call flush() if message level >= log_level
     void flush_on(logging::level::level_enum log_level);
 
     virtual void flush();
 
     const std::vector<sink_ptr>& sinks() const;
 
     template <typename T> void log(logging::level::level_enum lvl, T&&);
 
 protected:
 
     virtual void _sink_it(details::log_msg&);
     bool _should_flush_on(const details::log_msg&);
 
     std::vector<sink_ptr> _sinks;
     formatter_ptr _formatter;
     level_t _level;
     level_t _flush_level;
     std::atomic_size_t _index;
 };
 
 class ostream_wrapper {
 public:
     ostream_wrapper(logger& l, logging::level::level_enum lvl);
 
     virtual ~ostream_wrapper();
     ostream_wrapper(const ostream_wrapper&) = delete;
     ostream_wrapper& operator=(const ostream_wrapper&) = delete;
 
     template <typename T> friend ostream_wrapper& operator<<(ostream_wrapper& w, T&& msg) {
         w._stream << msg;
 
         return w;
     }
 
     bool valid();
     void destroy();
 
 private:
     bool _valid;
     ::logger::logger& _logger;
     ::logging::level::level_enum _lvl;
     std::ostringstream _stream;
 };
 
 logger_ptr get();
 
 }
 
 template <typename T>
 void ::logger::logger::log(logging::level::level_enum lvl, T&& msg) {
 
     if (!should_log(lvl))
         return;
 
     ::logger::details::log_msg log_msg(lvl);
     log_msg.index = _index.fetch_add(1, std::memory_order_relaxed);
     log_msg.raw << msg;
     _sink_it(log_msg);
 }