#ifndef _DATE_TIME_ADJUST_FUNCTORS_HPP___

#define _DATE_TIME_ADJUST_FUNCTORS_HPP___

/* Copyright (c) 2002,2003 CrystalClear Software, Inc.

 * Use, modification and distribution is subject to the 

 * Boost Software License, Version 1.0. (See accompanying

 * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)

 * Author: Jeff Garland, Bart Garst

 * $Date: 2008-02-27 15:00:24 -0500 (Wed, 27 Feb 2008) $

 */

#include "boost/date_time/date.hpp"

#include "boost/date_time/wrapping_int.hpp"

namespace boost {

namespace date_time {

  //! Functor to iterate a fixed number of days

  template<class date_type>

  class day_functor 

  {

  public:

    typedef typename date_type::duration_type duration_type;

    day_functor(int f) : f_(f) {}

    duration_type get_offset(const date_type& d) const 

    {

      // why is 'd' a parameter???

      // fix compiler warnings

      d.year();

      return duration_type(f_);

    }

    duration_type get_neg_offset(const date_type& d) const 

    {

      // fix compiler warnings

      d.year();

      return duration_type(-f_);

    }

  private:

    int f_;

  };

  //! Provides calculation to find next nth month given a date

  /*! This adjustment function provides the logic for 'month-based'

   *  advancement on a ymd based calendar.  The policy it uses 

   *  to handle the non existant end of month days is to back

   *  up to the last day of the month.  Also, if the starting

   *  date is the last day of a month, this functor will attempt

   *  to adjust to the end of the month.

   */

  template<class date_type>

  class month_functor 

  {

  public:

    typedef typename date_type::duration_type duration_type;

    typedef typename date_type::calendar_type cal_type;

    typedef typename cal_type::ymd_type ymd_type;

    typedef typename cal_type::day_type day_type;

    month_functor(int f) : f_(f), origDayOfMonth_(0) {}

    duration_type get_offset(const date_type& d) const 

    {

      ymd_type ymd(d.year_month_day());

      if (origDayOfMonth_ == 0) {

        origDayOfMonth_ = ymd.day;

        day_type endOfMonthDay(cal_type::end_of_month_day(ymd.year,ymd.month));

        if (endOfMonthDay == ymd.day) {

          origDayOfMonth_ = -1; //force the value to the end of month

        }

      }

      typedef date_time::wrapping_int2<short,1,12> wrap_int2;

      typedef typename wrap_int2::int_type int_type;

      wrap_int2 wi(ymd.month);

      //calc the year wrap around, add() returns 0 or 1 if wrapped

      int_type year = wi.add(static_cast<int_type>(f_)); 

      year = static_cast<int_type>(year + ymd.year); //calculate resulting year

//       std::cout << "trace wi: " << wi.as_int() << std::endl;

//       std::cout << "trace year: " << year << std::endl;

      //find the last day for the new month

      day_type resultingEndOfMonthDay(cal_type::end_of_month_day(year, wi.as_int()));

      //original was the end of month -- force to last day of month

      if (origDayOfMonth_ == -1) {

        return date_type(year, wi.as_int(), resultingEndOfMonthDay) - d;

      }

      day_type dayOfMonth = origDayOfMonth_;

      if (dayOfMonth > resultingEndOfMonthDay) {

        dayOfMonth = resultingEndOfMonthDay;

      }

      return date_type(year, wi.as_int(), dayOfMonth) - d;

    }

    //! Returns a negative duration_type

    duration_type get_neg_offset(const date_type& d) const 

    {

      ymd_type ymd(d.year_month_day());

      if (origDayOfMonth_ == 0) {

        origDayOfMonth_ = ymd.day;

        day_type endOfMonthDay(cal_type::end_of_month_day(ymd.year,ymd.month));

        if (endOfMonthDay == ymd.day) {

          origDayOfMonth_ = -1; //force the value to the end of month

        }

      }

      typedef date_time::wrapping_int2<short,1,12> wrap_int2;

      typedef typename wrap_int2::int_type int_type;

      wrap_int2 wi(ymd.month);

      //calc the year wrap around, add() returns 0 or 1 if wrapped

      int_type year = wi.subtract(static_cast<int_type>(f_)); 

      year = static_cast<int_type>(year + ymd.year); //calculate resulting year

      //find the last day for the new month

      day_type resultingEndOfMonthDay(cal_type::end_of_month_day(year, wi.as_int()));

      //original was the end of month -- force to last day of month

      if (origDayOfMonth_ == -1) {

        return date_type(year, wi.as_int(), resultingEndOfMonthDay) - d;

      }

      day_type dayOfMonth = origDayOfMonth_;

      if (dayOfMonth > resultingEndOfMonthDay) {

        dayOfMonth = resultingEndOfMonthDay;

      }

      return date_type(year, wi.as_int(), dayOfMonth) - d;

    }

  private:

    int f_;

    mutable short origDayOfMonth_;

  };

  //! Functor to iterate a over weeks

  template<class date_type>

  class week_functor 

  {

  public:

    typedef typename date_type::duration_type duration_type;

    typedef typename date_type::calendar_type calendar_type;

    week_functor(int f) : f_(f) {}

    duration_type get_offset(const date_type& d) const 

    {

      // why is 'd' a parameter???

      // fix compiler warnings

      d.year();

      return duration_type(f_*calendar_type::days_in_week());

    }

    duration_type get_neg_offset(const date_type& d) const 

    {

      // fix compiler warnings

      d.year();

      return duration_type(-f_*calendar_type::days_in_week());

    }

  private:

    int f_;

  };

  //! Functor to iterate by a year adjusting for leap years

  template<class date_type>

  class year_functor 

  {

  public:

    //typedef typename date_type::year_type year_type;

    typedef typename date_type::duration_type duration_type;

    year_functor(int f) : _mf(f * 12) {}

    duration_type get_offset(const date_type& d) const 

    {

      return _mf.get_offset(d);

    }

    duration_type get_neg_offset(const date_type& d) const 

    {

      return _mf.get_neg_offset(d);

    }

  private:

    month_functor<date_type> _mf;

  };

} }//namespace date_time

#endif