text: //
  // Copyright(c) 2015 Gabi Melman.
  // Distributed under the MIT License (http://opensource.org/licenses/MIT)
  //
  
  #pragma once
  
  #include "../formatter.h"
  #include "../details/log_msg.h"
  #include "../details/os.h"
  #include "../fmt/fmt.h"
  
  #include <chrono>
  #include <ctime>
  #include <memory>
  #include <mutex>
  #include <string>
  #include <thread>
  #include <utility>
  #include <vector>
  #include <array>
  
  namespace spdlog {
  namespace details {
  class flag_formatter {
    public:
      virtual ~flag_formatter() {
      }
      virtual void format(details::log_msg& msg, const std::tm& tm_time) = 0;
  };
  
  ///////////////////////////////////////////////////////////////////////
  // name & level pattern appenders
  ///////////////////////////////////////////////////////////////////////
  namespace {
  class name_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << *msg.logger_name;
      }
  };
  }
  
  // log level appender
  class level_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << level::to_str(msg.level);
      }
  };
  
  // short log level appender
  class short_level_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << level::to_short_str(msg.level);
      }
  };
  
  ///////////////////////////////////////////////////////////////////////
  // Date time pattern appenders
  ///////////////////////////////////////////////////////////////////////
  
  static const char* ampm(const tm& t) {
      return t.tm_hour >= 12 ? "PM" : "AM";
  }
  
  static int to12h(const tm& t) {
      return t.tm_hour > 12 ? t.tm_hour - 12 : t.tm_hour;
  }
  
  //Abbreviated weekday name
  static const std::string days[] { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
  class a_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << days[tm_time.tm_wday];
      }
  };
  
  //Full weekday name
  static const std::string full_days[] { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
  class A_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << full_days[tm_time.tm_wday];
      }
  };
  
  //Abbreviated month
  static const std::string  months[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec" };
  class b_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << months[tm_time.tm_mon];
      }
  };
  
  //Full month name
  static const std::string full_months[] { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" };
  class B_formatter: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << full_months[tm_time.tm_mon];
      }
  };
  
  
  //write 2 ints separated by sep with padding of 2
  static fmt::MemoryWriter& pad_n_join(fmt::MemoryWriter& w, int v1, int v2, char sep) {
      w << fmt::pad(v1, 2, '0') << sep << fmt::pad(v2, 2, '0');
      return w;
  }
  
  //write 3 ints separated by sep with padding of 2
  static fmt::MemoryWriter& pad_n_join(fmt::MemoryWriter& w, int v1, int v2, int v3, char sep) {
      w << fmt::pad(v1, 2, '0') << sep << fmt::pad(v2, 2, '0') << sep << fmt::pad(v3, 2, '0');
      return w;
  }
  
  
  //Date and time representation (Thu Aug 23 15:35:46 2014)
  class c_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << days[tm_time.tm_wday] << ' ' << months[tm_time.tm_mon] << ' ' << tm_time.tm_mday << ' ';
          pad_n_join(msg.formatted, tm_time.tm_hour, tm_time.tm_min, tm_time.tm_sec, ':') << ' ' << tm_time.tm_year + 1900;
      }
  };
  
  
  // year - 2 digit
  class C_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(tm_time.tm_year % 100, 2, '0');
      }
  };
  
  
  
  // Short MM/DD/YY date, equivalent to %m/%d/%y 08/23/01
  class D_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          pad_n_join(msg.formatted, tm_time.tm_mon + 1, tm_time.tm_mday, tm_time.tm_year % 100, '/');
      }
  };
  
  
  // year - 4 digit
  class Y_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << tm_time.tm_year + 1900;
      }
  };
  
  // month 1-12
  class m_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(tm_time.tm_mon + 1, 2, '0');
      }
  };
  
  // day of month 1-31
  class d_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(tm_time.tm_mday, 2, '0');
      }
  };
  
  // hours in 24 format  0-23
  class H_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(tm_time.tm_hour, 2, '0');
      }
  };
  
  // hours in 12 format  1-12
  class I_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(to12h(tm_time), 2, '0');
      }
  };
  
  // minutes 0-59
  class M_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(tm_time.tm_min, 2, '0');
      }
  };
  
  // seconds 0-59
  class S_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << fmt::pad(tm_time.tm_sec, 2, '0');
      }
  };
  
  // milliseconds
  class e_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          auto duration = msg.time.time_since_epoch();
          auto millis = std::chrono::duration_cast<std::chrono::milliseconds>(duration).count() % 1000;
          msg.formatted << fmt::pad(static_cast<int>(millis), 3, '0');
      }
  };
  
  // microseconds
  class f_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          auto duration = msg.time.time_since_epoch();
          auto micros = std::chrono::duration_cast<std::chrono::microseconds>(duration).count() % 1000000;
          msg.formatted << fmt::pad(static_cast<int>(micros), 6, '0');
      }
  };
  
  // nanoseconds
  class F_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          auto duration = msg.time.time_since_epoch();
          auto ns = std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count() % 1000000000;
          msg.formatted << fmt::pad(static_cast<int>(ns), 9, '0');
      }
  };
  
  class E_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          auto duration = msg.time.time_since_epoch();
          auto seconds = std::chrono::duration_cast<std::chrono::seconds>(duration).count();
          msg.formatted << seconds;
      }
  };
  
  // AM/PM
  class p_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          msg.formatted << ampm(tm_time);
      }
  };
  
  
  // 12 hour clock 02:55:02 pm
  class r_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          pad_n_join(msg.formatted, to12h(tm_time), tm_time.tm_min, tm_time.tm_sec, ':') << ' ' << ampm(tm_time);
      }
  };
  
  // 24-hour HH:MM time, equivalent to %H:%M
  class R_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          pad_n_join(msg.formatted, tm_time.tm_hour, tm_time.tm_min, ':');
      }
  };
  
  // ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S
  class T_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
          pad_n_join(msg.formatted, tm_time.tm_hour, tm_time.tm_min, tm_time.tm_sec, ':');
      }
  };
  
  // ISO 8601 offset from UTC in timezone (+-HH:MM)
  class z_formatter SPDLOG_FINAL: public flag_formatter {
    public:
      const std::chrono::seconds cache_refresh = std::chrono::seconds(5);
  
      z_formatter(): _last_update(std::chrono::seconds(0)), _offset_minutes(0) {
      }
      z_formatter(const z_formatter&) = delete;
      z_formatter& operator=(const z_formatter&) = delete;
  
      void format(details::log_msg& msg, const std::tm& tm_time) override {
  #ifdef _WIN32
          int total_minutes = get_cached_offset(msg, tm_time);
  #else
          // No need to chache under gcc,
          // it is very fast (already stored in tm.tm_gmtoff)
          int total_minutes = os::utc_minutes_offset(tm_time);
  #endif
          bool is_negative = total_minutes < 0;
          char sign;
          if (is_negative) {
              total_minutes = -total_minutes;
              sign = '-';
          } else {
              sign = '+';
          }
  
          int h = total_minutes / 60;
          int m = total_minutes % 60;
          msg.formatted << sign;
          pad_n_join(msg.formatted, h, m, ':');
      }
    private:
      log_clock::time_point _last_update;
      int _offset_minutes;
      std::mutex _mutex;
  
      int get_cached_offset(const log_msg& msg, const std::tm& tm_time) {
          using namespace std::chrono;
          std::lock_guard<std::mutex> l(_mutex);
          if (msg.time - _last_update >= cache_refresh) {
              _offset_minutes = os::utc_minutes_offset(tm_time);
              _last_update = msg.time;
          }
          return _offset_minutes;
      }
  };
  
  
  
  // Thread id
  class t_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << msg.thread_id;
      }
  };
  
  // Current pid
  class pid_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << details::os::pid();
      }
  };
  
  // message counter formatter
  class i_formatter SPDLOG_FINAL : public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << fmt::pad(msg.msg_id, 6, '0');
      }
  };
  
  class v_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << fmt::StringRef(msg.raw.data(), msg.raw.size());
      }
  };
  
  class ch_formatter SPDLOG_FINAL: public flag_formatter {
    public:
      explicit ch_formatter(char ch): _ch(ch) {
      }
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << _ch;
      }
    private:
      char _ch;
  };
  
  
  //aggregate user chars to display as is
  class aggregate_formatter SPDLOG_FINAL: public flag_formatter {
    public:
      aggregate_formatter() {
      }
      void add_ch(char ch) {
          _str += ch;
      }
      void format(details::log_msg& msg, const std::tm&) override {
          msg.formatted << _str;
      }
    private:
      std::string _str;
  };
  
  // Full info formatter
  // pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
  class full_formatter SPDLOG_FINAL: public flag_formatter {
      void format(details::log_msg& msg, const std::tm& tm_time) override {
  #ifndef SPDLOG_NO_DATETIME
          auto duration = msg.time.time_since_epoch();
          auto millis = std::chrono::duration_cast<std::chrono::milliseconds>(duration).count() % 1000;
  
          /* Slower version(while still very fast - about 3.2 million lines/sec under 10 threads),
          msg.formatted.write("[{:d}-{:02d}-{:02d} {:02d}:{:02d}:{:02d}.{:03d}] [{}] [{}] {} ",
          tm_time.tm_year + 1900,
          tm_time.tm_mon + 1,
          tm_time.tm_mday,
          tm_time.tm_hour,
          tm_time.tm_min,
          tm_time.tm_sec,
          static_cast<int>(millis),
          msg.logger_name,
          level::to_str(msg.level),
          msg.raw.str());*/
  
  
          // Faster (albeit uglier) way to format the line (5.6 million lines/sec under 10 threads)
          msg.formatted << '[' << static_cast<unsigned int>(tm_time.tm_year + 1900) << '-'
                        << fmt::pad(static_cast<unsigned int>(tm_time.tm_mon + 1), 2, '0') << '-'
                        << fmt::pad(static_cast<unsigned int>(tm_time.tm_mday), 2, '0') << ' '
                        << fmt::pad(static_cast<unsigned int>(tm_time.tm_hour), 2, '0') << ':'
                        << fmt::pad(static_cast<unsigned int>(tm_time.tm_min), 2, '0') << ':'
                        << fmt::pad(static_cast<unsigned int>(tm_time.tm_sec), 2, '0') << '.'
                        << fmt::pad(static_cast<unsigned int>(millis), 3, '0') << "] ";
  
          //no datetime needed
  #else
          (void)tm_time;
  #endif
  
  #ifndef SPDLOG_NO_NAME
          msg.formatted << '[' << *msg.logger_name << "] ";
  #endif
  
          msg.formatted << '[' << level::to_str(msg.level) << "] ";
          msg.formatted << fmt::StringRef(msg.raw.data(), msg.raw.size());
      }
  };
  
  
  
  }
  }
  ///////////////////////////////////////////////////////////////////////////////
  // pattern_formatter inline impl
  ///////////////////////////////////////////////////////////////////////////////
  inline spdlog::pattern_formatter::pattern_formatter(const std::string& pattern, pattern_time_type pattern_time)
      : _pattern_time(pattern_time) {
      compile_pattern(pattern);
  }
  
  inline void spdlog::pattern_formatter::compile_pattern(const std::string& pattern) {
      auto end = pattern.end();
      std::unique_ptr<details::aggregate_formatter> user_chars;
      for (auto it = pattern.begin(); it != end; ++it) {
          if (*it == '%') {
              if (user_chars) //append user chars found so far
                  _formatters.push_back(std::move(user_chars));
  
              if (++it != end)
                  handle_flag(*it);
              else
                  break;
          } else { // chars not following the % sign should be displayed as is
              if (!user_chars)
                  user_chars = std::unique_ptr<details::aggregate_formatter>(new details::aggregate_formatter());
              user_chars->add_ch(*it);
          }
      }
      if (user_chars) { //append raw chars found so far
          _formatters.push_back(std::move(user_chars));
      }
  
  }
  inline void spdlog::pattern_formatter::handle_flag(char flag) {
      switch (flag) {
      // logger name
      case 'n':
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::name_formatter()));
          break;
  
      case 'l':
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::level_formatter()));
          break;
  
      case 'L':
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::short_level_formatter()));
          break;
  
      case('t'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::t_formatter()));
          break;
  
      case('v'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::v_formatter()));
          break;
  
      case('a'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::a_formatter()));
          break;
  
      case('A'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::A_formatter()));
          break;
  
      case('b'):
      case('h'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::b_formatter()));
          break;
  
      case('B'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::B_formatter()));
          break;
      case('c'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::c_formatter()));
          break;
  
      case('C'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::C_formatter()));
          break;
  
      case('Y'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::Y_formatter()));
          break;
  
      case('D'):
      case('x'):
  
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::D_formatter()));
          break;
  
      case('m'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::m_formatter()));
          break;
  
      case('d'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::d_formatter()));
          break;
  
      case('H'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::H_formatter()));
          break;
  
      case('I'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::I_formatter()));
          break;
  
      case('M'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::M_formatter()));
          break;
  
      case('S'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::S_formatter()));
          break;
  
      case('e'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::e_formatter()));
          break;
  
      case('f'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::f_formatter()));
          break;
      case('F'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::F_formatter()));
          break;
  
      case('E'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::E_formatter()));
          break;
  
      case('p'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::p_formatter()));
          break;
  
      case('r'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::r_formatter()));
          break;
  
      case('R'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::R_formatter()));
          break;
  
      case('T'):
      case('X'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::T_formatter()));
          break;
  
      case('z'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::z_formatter()));
          break;
  
      case ('+'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::full_formatter()));
          break;
  
      case ('P'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::pid_formatter()));
          break;
  
  
      case ('i'):
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::i_formatter()));
          break;
  
      default: //Unknown flag appears as is
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::ch_formatter('%')));
          _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::ch_formatter(flag)));
          break;
      }
  }
  
  inline std::tm spdlog::pattern_formatter::get_time(details::log_msg& msg) {
      if (_pattern_time == pattern_time_type::local)
          return details::os::localtime(log_clock::to_time_t(msg.time));
      else
          return details::os::gmtime(log_clock::to_time_t(msg.time));
  }
  
  inline void spdlog::pattern_formatter::format(details::log_msg& msg) {
  
  #ifndef SPDLOG_NO_DATETIME
      auto tm_time = get_time(msg);
  #else
      std::tm tm_time;
  #endif
      for (auto& f : _formatters) {
          f->format(msg, tm_time);
      }
      //write eol
      msg.formatted.write(details::os::eol, details::os::eol_size);
  }
  