--          This file is part of SmallEiffel The GNU Eiffel Compiler.
--          Copyright (C) 1994-98 LORIA - UHP - CRIN - INRIA - FRANCE
--            Dominique COLNET and Suzanne COLLIN - colnet@loria.fr 
--                       http://www.loria.fr/SmallEiffel
-- SmallEiffel 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  2, or (at your option)  any  later 
-- version. SmallEiffel 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  SmallEiffel;  see the file COPYING.  If not,
-- write to the  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-- Boston, MA 02111-1307, USA.
--
class DATE
   
inherit 
   ANY 
      redefine print_on
      end;
   
creation {ANY}
   make

feature {ANY}
   
   print_on(file: OUTPUT_STREAM) is
      do
	 file.put_string("day : ");
	 file.put_integer(day);
	 file.put_string(" minute : ");
	 file.put_integer(min);
      end; 
   
   minutes_to(after: DATE): INTEGER is
	 -- Count of minutes to go to `after'. 
      require
	 after >= Current
      do
	 Result := ((after.day - day) * 24 * 60 + (after.min - min));
      ensure
	 Result >= 0;
      end;
   
   day_night_to(d2: DATE): ARRAY[INTEGER] is
	 -- Result @ Result.lower : Night time.
	 -- Result @ Result.upper : Day time.
      require
	 d2 >= Current
      local
	 min_jour, min_nuit: INTEGER;
	 save_day, save_min: INTEGER;
      do
	 from  
	    save_day := day;
	    save_min := min;
	 until
	    is_equal(d2)
	 loop
	    if day_time then
	       min_jour := min_jour + 1;
	    else
	       min_nuit := min_nuit + 1;
	    end;
	    add_time(1);
	 end;
	 day := save_day;
	 min := save_min;
	 Result := <<min_jour,min_nuit>>
      ensure
	 Result.count = 2;
	 (Result @ 1) + (Result @ 2) = minutes_to(d2)
      end;
   
   infix ">=" (d2: like Current): BOOLEAN is
      require
	 d2 /= Void
      do
	 Result := (day > d2.day) or else
		   ((day = d2.day) and then (min >= d2.min));
      end
   
   day_time: BOOLEAN is
	 -- Is it Sunny ?
      do
	 Result := (min >= 6*60) and (min <= 22*60);
      end;
   
   nigth_time: BOOLEAN is
	 -- Is it the night ?
      do
	 Result := not day_time;
      end;

feature {ANY} -- Modifications :
   
   make(vday, vmin: INTEGER) is
      do
	 day := vday;
	 min := vmin;
      ensure
	 day = vday;
	 min = vmin;
      end;
   
   add_time(nb_min: INTEGER) is
      do
	 min := min + nb_min;
	 if min > (24*60) then
	    day := day + (min // (24*60));
	    min := min \\ (24*60);
	 end;
      end;
   
feature {DATE}
   
   day, min : INTEGER;

invariant
   
   day >= 0;
   
   min >= 0;
   
   min < 24 * 60;

end -- DATE