FUNCTION {{p}}sewer_fee
  IMPORTING
    iv_tank_litres TYPE i
    iv_distance_km TYPE i
    iv_mains_sewer TYPE abap_bool
  EXPORTING
    ev_skip        TYPE abap_bool
  CHANGING
    cv_fee         TYPE decfloat34
  EXCEPTIONS
    invalid_litres.

  CONSTANTS c_base_fee    TYPE decfloat34 VALUE '75'.
  CONSTANTS c_step_fee    TYPE decfloat34 VALUE '20'.
  CONSTANTS c_step_litres TYPE i VALUE 500.
  CONSTANTS c_km_rate     TYPE decfloat34 VALUE '1.5'.
  CONSTANTS c_travel_max  TYPE decfloat34 VALUE '60'.
  CONSTANTS c_fee_max     TYPE decfloat34 VALUE '900'.
  DATA lv_steps  TYPE i.
  DATA lv_travel TYPE decfloat34.

  ev_skip = abap_true.

  IF iv_tank_litres < 1.
    RAISE invalid_litres.
  ENDIF.

  IF iv_mains_sewer = abap_true.
    ev_skip = abap_true.
    RETURN.
  ENDIF.

  cv_fee = c_base_fee.
  IF iv_tank_litres > 1000.
    lv_steps = ( iv_tank_litres - 1001 ) DIV c_step_litres + 1.
    cv_fee = cv_fee + lv_steps * c_step_fee.
  ENDIF.

  IF iv_distance_km > 0.
    lv_travel = iv_distance_km * c_km_rate.
    IF lv_travel > c_travel_max.
      lv_travel = c_travel_max.
    ENDIF.
    cv_fee = cv_fee + lv_travel.
  ENDIF.

  IF cv_fee > c_fee_max.
    cv_fee = c_fee_max.
  ENDIF.

ENDFUNCTION.