/*
 * Copyright (c) 2003-2009, John Wiegley.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of New Artisans LLC nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @addtogroup util
 */

/**
 * @file   times.h
 * @author John Wiegley
 *
 * @ingroup util
 *
 * @brief datetime_t and date_t objects
 */
#ifndef _TIMES_H
#define _TIMES_H

#include "utils.h"

namespace ledger {

DECLARE_EXCEPTION(datetime_error, std::runtime_error);
DECLARE_EXCEPTION(date_error, std::runtime_error);

typedef boost::posix_time::ptime	datetime_t;
typedef datetime_t::time_duration_type	time_duration_t;

inline bool is_valid(const datetime_t& moment) {
  return ! moment.is_not_a_date_time();
}

typedef boost::gregorian::date          date_t;
typedef boost::gregorian::date_duration date_duration_t;

inline bool is_valid(const date_t& moment) {
  return ! moment.is_not_a_date();
}

#ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK
#define CURRENT_TIME() boost::posix_time::microsec_clock::universal_time()
#else
#define CURRENT_TIME() boost::posix_time::second_clock::universal_time()
#endif
#define CURRENT_DATE() boost::gregorian::day_clock::universal_day()

extern int                   start_of_week;
extern optional<std::string> input_date_format;

int string_to_day_of_week(const std::string& str);

datetime_t parse_datetime(const char * str, int current_year = -1);

inline datetime_t parse_datetime(const std::string& str, int current_year = -1) {
  return parse_datetime(str.c_str(), current_year);
}

date_t parse_date(const char * str, int current_year = -1);

inline date_t parse_date(const std::string& str, int current_year = -1) {
  return parse_date(str.c_str(), current_year);
}

inline std::time_t to_time_t(const ptime& t) 
{ 
  if( t == posix_time::neg_infin ) 
    return 0; 
  else if( t == posix_time::pos_infin ) 
    return LONG_MAX; 
  ptime start(date(1970,1,1)); 
  return (t-start).total_seconds(); 
}

extern std::string output_datetime_format;

inline std::string format_datetime(const datetime_t& when,
				   const optional<std::string>& format = none)
{
  char buf[256];
  time_t moment = to_time_t(when);
  std::strftime(buf, 255, format ? format->c_str() :
		output_datetime_format.c_str(), std::localtime(&moment));
  return buf;
}

extern std::string output_date_format;

inline std::string format_date(const date_t& when,
			       const optional<std::string>& format = none)
{
  char buf[256];
  std::tm moment = gregorian::to_tm(when);
  std::strftime(buf, 255, format ? format->c_str() :
		output_date_format.c_str(), &moment);
  return buf;
}

/**
 * @brief Brief
 *
 * Long.
 */
struct interval_t
{
  int	 years;
  int	 months;
  int	 days;
  bool	 weekly;
  date_t begin;
  date_t end;

  interval_t(int	   _days   = 0,
	     int	   _months = 0,
	     int	   _years  = 0,
	     bool	   _weekly = false,
	     const date_t& _begin  = date_t(),
	     const date_t& _end	   = date_t())
    : years(_years), months(_months), days(_days),
      weekly(_weekly), begin(_begin), end(_end) {
    TRACE_CTOR(interval_t,
	       "int, int, int, bool, const date_t&, const date_t&");
  }
  interval_t(const interval_t& other)
    : years(other.years),
      months(other.months),
      days(other.days),
      weekly(other.weekly),
      begin(other.begin),
      end(other.end) {
    TRACE_CTOR(interval_t, "copy");
  }
  interval_t(const string& desc)
    : years(0), months(0), days(0), weekly(false), begin(), end() {
    TRACE_CTOR(interval_t, "const string&");
    std::istringstream stream(desc);
    parse(stream);
  }

  ~interval_t() throw() {
    TRACE_DTOR(interval_t);
  }

  operator bool() const {
    return years != 0 || months != 0  || days != 0;
  }

  void   set_start(const date_t& moment) {
    begin = first(moment);
  }

  date_t first(const optional<date_t>& moment = none);
  date_t increment(const date_t&) const;

  void   parse(std::istream& in);
};

} // namespace ledger

#endif // _TIMES_H