!! File Time.ili Release 2020-02-19

INTERLIS 2.3;

!! 2020-02-19 CLASS TimeZone defined as not ABSTRACT
!!@precursorVersion = 2017-04-13

CONTRACTED REFSYSTEM MODEL Time (en) AT "http://www.interlis.ch/models"
  VERSION "2020-02-19" =

  IMPORTS Units;

  STRUCTURE DayOfYear =
    Month: 1 .. 12 [INTERLIS.M];
    SUBDIVISION Day: 1 .. 31 [INTERLIS.d];
  END DayOfYear;

  STRUCTURE HMDiffWithinDay =
    Hours: -23 .. 23 CIRCULAR [INTERLIS.h];
    CONTINUOUS SUBDIVISION Minutes: 0 .. 59 [INTERLIS.min];
  END HMDiffWithinDay;

  DOMAIN
    WeekDay = (WorkingDay (Monday, Tuesday, Wednesday,
                           Thursday, Friday, Saturday),
               Sunday) CIRCULAR;

    HMDiffWDay = FORMAT BASED ON HMDiffWithinDay (Hours ":" Minutes);
    DifferenceToUTC EXTENDS HMDiffWDay = MANDATORY "-13:00" .. "13:00";
                                         !! UTC := LocTime + Diff

  FUNCTION AppropriateDate (dayOfYear: MANDATORY DayOfYear;
                            weekDay: WeekDay): DayOfYear
    // returns first parameter if second is undefined,
       returns first day from (incl) first parameter being the
       requested weekday //;

  FUNCTION DSTOrdered (day1: DayOfYear; day2: DayOfYear) : BOOLEAN
    // returns TRUE if the second parameter comes after the
       first parameter or if both parameters are equal //;

  STRUCTURE DSTransition =
    TransitionDSTime: MANDATORY HMDiffWDay;
    FirstDate: MANDATORY DayOfYear;
    DayOfWeek: WeekDay;
    TransitionDate: DayOfYear := AppropriateDate (FirstDate, DayOfWeek);
  END DSTransition;

  STRUCTURE DaylightSavingPeriod =
    DSToUTC: DifferenceToUTC;
    From: MANDATORY INTERLIS.GregorianYear;
    To:   MANDATORY INTERLIS.GregorianYear;
    DSStart: MANDATORY DSTransition;
    DSEnd: MANDATORY DSTransition;
  MANDATORY CONSTRAINT
    DSTOrdered (DSStart->FirstDate, DSEnd->FirstDate);
  MANDATORY CONSTRAINT
    To >= From;
  END DaylightSavingPeriod;

  FUNCTION DSPOverlaps (periods: BAG {1..*} OF DaylightSavingPeriod) : BOOLEAN
    // returns TRUE if any one of the periods overlap //;


  TOPIC TimeZone =

    CLASS TimeZone EXTENDS INTERLIS.SCALSYSTEM =
    PARAMETER
      Unit (EXTENDED): NUMERIC [INTERLIS.TIME];
    END TimeZone;

    CLASS BaseTimeZone EXTENDS INTERLIS.TIMESYSTEMS.TIMEOFDAYSYS =
                               !! TimeZone without daylight saving
      DiffToUTC: DifferenceToUTC;
    END BaseTimeZone;

    CLASS DaylightSavingTZ EXTENDS INTERLIS.TIMESYSTEMS.TIMEOFDAYSYS =
      Periods: BAG {1..*} OF DaylightSavingPeriod;
    MANDATORY CONSTRAINT
      NOT ( DSPOverlaps (Periods) );
    END DaylightSavingTZ;

    ASSOCIATION DaylightSavingTZOf =
      BaseTZ -<> BaseTimeZone;
      DSTZ -- DaylightSavingTZ;
    END DaylightSavingTZOf;

  END TimeZone;

END Time.