--          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 PARKING

creation {ANY}
   make

feature {ANY}
   
   lower_level: INTEGER is
      do
	 Result := level_list.lower;
      end;
   
   upper_level: INTEGER is
      do
	 Result := level_list.upper;
      end;
   
   hour_price: REAL;
   
   default_hour_price: REAL is 1.50;
   
   count: INTEGER is
      local
	 i: INTEGER;
      do
	 from  
	    i := lower_level;
	 until
	    i > upper_level
	 loop
	    Result := Result + level_count(i);
	    i := i + 1;
	 end;
      end;
   
   clock: DATE;
   
   level_count(number: INTEGER): INTEGER is
      require
	 number <= upper_level;
	 lower_level <= number;
      do
	 Result := (level_list @ number).count;
      ensure
	 Result >= 0;
      end;

feature {ANY} -- Modifications :
   
   make(ll: like level_list) is
      require
	 ll /= Void
      do
	 !!clock.make(0,360);
	 hour_price := default_hour_price;
	 level_list := ll;
	 last_car := 0;
      ensure
	 hour_price = default_hour_price;
	 level_list = ll;
	 last_car = 0;
      end;
   
   arrival: INTEGER is
      -- Gives 0 when no more place.
      local
	 i: INTEGER;
      do
	 from  
	    i := lower_level;
	 until
	    (i > upper_level) or else	    
	    (not (level_list @ i).full)
	 loop
	    i := i + 1;
	 end;
	 if (i > upper_level) or else 
	    (level_list @ i).full  
	 then
	    Result := 0;
	 else
	    last_car := last_car + 1;
	    level_list.item(i).arrival(last_car,clone(clock));
	    Result := last_car;
	 end;
      ensure
	 Result >= 0;
      end;
   
   departure(car: INTEGER): REAL is
	 -- Gives the price to pay or -1 when car has already leaved. 
      require
	 car > 0;
      local
	 i: INTEGER;
	 stop: BOOLEAN;
	 c: like clock;
      do
	 from  
	    i := lower_level;
	    stop := level_list.count <= 0;
	    Result := -1;
	    c := clone(clock);
	 until
	    stop
	 loop
	    Result := (level_list @ i).departure(car,c,hour_price);
	    i := i + 1;
	    stop := (Result >= 0) or (i > upper_level);
	 end;
      end;
   
   add_time(incr: INTEGER) is
      do
	 clock.add_time(incr);
      end;
   
   set_hour_price(hp: REAL) is
      require
	 hp >= 0;
      do
	 hour_price := hp;
      ensure
	 hour_price = hp;
      end;

feature {NONE}
   
   level_list: ARRAY[LEVEL];
   
   last_car: INTEGER;

invariant
   
   valid_price: hour_price >= 0;
	 
   clock /= Void;
   
   last_car >= 0;
   
   level_list /= Void;
   
end -- PARKING