FUNCTION {{p}}banquet_fee
  IMPORTING
    iv_order_id TYPE string
  EXPORTING
    ev_total TYPE decfloat34
    ev_portions TYPE i
    ev_dishes TYPE i
  EXCEPTIONS
    no_positions
    unknown_dish
    invalid_quantity.

  DATA lt_positions TYPE STANDARD TABLE OF {{p}}pos.
  DATA lt_dishes TYPE HASHED TABLE OF {{p}}dish WITH UNIQUE KEY dish_id.
  DATA lt_seen TYPE HASHED TABLE OF {{p}}pos WITH UNIQUE KEY dish_id.
  DATA ls_position TYPE {{p}}pos.
  DATA ls_dish TYPE {{p}}dish.

  CLEAR: ev_total, ev_portions, ev_dishes.

  SELECT order_id, pos_no, dish_id, qty
    FROM {{p}}pos
    WHERE order_id = @iv_order_id
    INTO TABLE @lt_positions.

  IF lt_positions IS INITIAL.
    RAISE no_positions.
  ENDIF.

  LOOP AT lt_positions INTO ls_position.
    IF ls_position-qty <= 0.
      RAISE invalid_quantity.
    ENDIF.
  ENDLOOP.

  SELECT dish_id, dish_name, price
    FROM {{p}}dish
    INTO TABLE @lt_dishes.

  LOOP AT lt_positions INTO ls_position.
    READ TABLE lt_dishes INTO ls_dish WITH TABLE KEY dish_id = ls_position-dish_id.
    IF sy-subrc <> 0.
      RAISE unknown_dish.
    ENDIF.

    ev_total = ev_total + ls_dish-price * ls_position-qty.
    ev_portions = ev_portions + ls_position-qty.
    INSERT ls_position INTO TABLE lt_seen.
  ENDLOOP.

  ev_dishes = lines( lt_seen ).

  IF ev_portions >= 50.
    ev_total = round( val = ev_total * 95 / 100 dec = 2 mode = cl_abap_math=>round_half_up ).
  ENDIF.

ENDFUNCTION.