CLASS {{p}}overdue_fine DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES ty_media TYPE c LENGTH 8.
    TYPES ty_amount TYPE p LENGTH 8 DECIMALS 2.
    TYPES:
      BEGIN OF ty_result,
        days_overdue    TYPE i,
        chargeable_days TYPE i,
        fine            TYPE ty_amount,
      END OF ty_result.

    METHODS calculate
      IMPORTING iv_due_date     TYPE d
                iv_return_date  TYPE d
                iv_media        TYPE ty_media
      RETURNING VALUE(rs_result) TYPE ty_result.

  PRIVATE SECTION.
    TYPES:
      BEGIN OF ty_media_rule,
        media      TYPE ty_media,
        rate       TYPE ty_amount,
        grace_days TYPE i,
      END OF ty_media_rule,
      tt_media_rule TYPE HASHED TABLE OF ty_media_rule WITH UNIQUE KEY media.

    CONSTANTS:
      c_max_fine     TYPE ty_amount VALUE '25.00',
      c_reminder_fee TYPE ty_amount VALUE '5.00',
      c_reminder_day TYPE i VALUE 30.

    METHODS media_rule
      IMPORTING iv_media       TYPE ty_media
      RETURNING VALUE(rs_rule) TYPE ty_media_rule.
ENDCLASS.


CLASS {{p}}overdue_fine IMPLEMENTATION.
  METHOD calculate.
    rs_result-days_overdue = iv_return_date - iv_due_date.
    IF rs_result-days_overdue <= 0.
      CLEAR rs_result.
      RETURN.
    ENDIF.

    DATA(ls_rule) = media_rule( iv_media ).
    IF ls_rule IS INITIAL.
      RETURN.
    ENDIF.

    rs_result-chargeable_days = nmax( val1 = rs_result-days_overdue - ls_rule-grace_days
                                      val2 = 0 ).
    rs_result-fine = rs_result-chargeable_days * ls_rule-rate.
    IF rs_result-days_overdue > c_reminder_day.
      rs_result-fine = rs_result-fine + c_reminder_fee.
    ENDIF.
    rs_result-fine = nmin( val1 = rs_result-fine
                           val2 = c_max_fine ).
  ENDMETHOD.

  METHOD media_rule.
    DATA(lt_rules) = VALUE tt_media_rule(
      ( media = 'BOOK' rate = '0.30' grace_days = 7 )
      ( media = 'DVD'  rate = '1.50' grace_days = 2 )
      ( media = 'GAME' rate = '2.50' grace_days = 0 ) ).
    READ TABLE lt_rules INTO rs_rule WITH TABLE KEY media = iv_media.
  ENDMETHOD.
ENDCLASS.