CLASS {{p}}dive_check DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC.

  PUBLIC SECTION.
    TYPES ty_reason     TYPE c LENGTH 10.
    TYPES ty_cert_level TYPE c LENGTH 1.

    CONSTANTS:
      BEGIN OF c_reason,
        ok     TYPE ty_reason VALUE 'OK',
        age    TYPE ty_reason VALUE 'AGE',
        cert   TYPE ty_reason VALUE 'CERT',
        depth  TYPE ty_reason VALUE 'DEPTH',
        dives  TYPE ty_reason VALUE 'DIVES',
        recent TYPE ty_reason VALUE 'RECENT',
      END OF c_reason.

    METHODS check_diver
      IMPORTING
        iv_cert_level TYPE ty_cert_level
        iv_depth      TYPE i
        iv_dives      TYPE i
        iv_last_dive  TYPE d
        iv_dive_date  TYPE d
        iv_age        TYPE i
      RETURNING
        VALUE(rv_reason) TYPE ty_reason.

  PRIVATE SECTION.
    CONSTANTS:
      c_min_age      TYPE i VALUE 12,
      c_deep_depth   TYPE i VALUE 30,
      c_days_deep    TYPE i VALUE 180,
      c_days_shallow TYPE i VALUE 365.

    TYPES:
      BEGIN OF ty_limit,
        cert      TYPE ty_cert_level,
        max_depth TYPE i,
        min_dives TYPE i,
      END OF ty_limit,
      tt_limit TYPE HASHED TABLE OF ty_limit WITH UNIQUE KEY cert.

    METHODS limits
      RETURNING VALUE(rt_limit) TYPE tt_limit.
    METHODS days_since_last_dive
      IMPORTING iv_last_dive TYPE d
                iv_dive_date TYPE d
      RETURNING VALUE(rv_days) TYPE i.
    METHODS max_days_since_last_dive
      IMPORTING iv_depth      TYPE i
      RETURNING VALUE(rv_days) TYPE i.
ENDCLASS.


CLASS {{p}}dive_check IMPLEMENTATION.
  METHOD check_diver.
    IF iv_age < c_min_age.
      rv_reason = c_reason-age.
      RETURN.
    ENDIF.

    DATA(lt_limit) = limits( ).
    READ TABLE lt_limit WITH TABLE KEY cert = iv_cert_level ASSIGNING FIELD-SYMBOL(<ls_limit>).
    IF sy-subrc <> 0.
      rv_reason = c_reason-cert.
      RETURN.
    ENDIF.

    IF iv_depth > <ls_limit>-max_depth.
      rv_reason = c_reason-depth.
      RETURN.
    ENDIF.

    IF iv_dives < <ls_limit>-min_dives.
      rv_reason = c_reason-dives.
      RETURN.
    ENDIF.

    IF iv_last_dive IS INITIAL.
      rv_reason = c_reason-recent.
      RETURN.
    ENDIF.

    IF days_since_last_dive( iv_last_dive = iv_last_dive
                             iv_dive_date = iv_dive_date ) > max_days_since_last_dive( iv_depth ).
      rv_reason = c_reason-recent.
      RETURN.
    ENDIF.

    rv_reason = c_reason-ok.
  ENDMETHOD.

  METHOD limits.
    rt_limit = VALUE #( ( cert = 'O' max_depth = 18  min_dives = 20 )
                        ( cert = 'A' max_depth = 30  min_dives = 50 )
                        ( cert = 'R' max_depth = 40  min_dives = 80 )
                        ( cert = 'D' max_depth = 40  min_dives = 100 ) ).
  ENDMETHOD.

  METHOD days_since_last_dive.
    rv_days = iv_dive_date - iv_last_dive.
  ENDMETHOD.

  METHOD max_days_since_last_dive.
    IF iv_depth > c_deep_depth.
      rv_days = c_days_deep.
    ELSE.
      rv_days = c_days_shallow.
    ENDIF.
  ENDMETHOD.
ENDCLASS.