CLASS {{p}}oil_settlement DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES ty_restaurant TYPE c LENGTH 10.

    TYPES:
      BEGIN OF ty_collection,
        restaurant   TYPE ty_restaurant,
        collected_on TYPE d,
        litres       TYPE i,
      END OF ty_collection.

    TYPES tt_collections TYPE STANDARD TABLE OF ty_collection WITH EMPTY KEY.

    TYPES:
      BEGIN OF ty_settlement,
        restaurant      TYPE ty_restaurant,
        total_litres    TYPE i,
        round_count     TYPE i,
        last_collection TYPE d,
      END OF ty_settlement.

    TYPES tt_settlements TYPE SORTED TABLE OF ty_settlement WITH UNIQUE KEY restaurant.

    METHODS settle
      IMPORTING it_collections        TYPE tt_collections
      RETURNING VALUE(rt_settlements) TYPE tt_settlements.

  PRIVATE SECTION.
    TYPES:
      BEGIN OF ty_buffer,
        restaurant      TYPE ty_restaurant,
        total_litres    TYPE i,
        round_count     TYPE i,
        last_collection TYPE d,
      END OF ty_buffer.

    TYPES tt_buffer TYPE HASHED TABLE OF ty_buffer WITH UNIQUE KEY restaurant.

    METHODS normalize
      IMPORTING iv_restaurant        TYPE ty_restaurant
      RETURNING VALUE(rv_restaurant) TYPE ty_restaurant.
ENDCLASS.


CLASS {{p}}oil_settlement IMPLEMENTATION.
  METHOD settle.
    DATA lt_buffer TYPE tt_buffer.

    LOOP AT it_collections INTO DATA(ls_collection).
      DATA(lv_restaurant) = normalize( ls_collection-restaurant ).
      IF lv_restaurant IS INITIAL OR ls_collection-litres <= 0.
        CONTINUE.
      ENDIF.

      ASSIGN lt_buffer[ restaurant = lv_restaurant ] TO FIELD-SYMBOL(<ls_buffer>).
      IF sy-subrc <> 0.
        INSERT VALUE #( restaurant = lv_restaurant ) INTO TABLE lt_buffer ASSIGNING <ls_buffer>.
      ENDIF.

      <ls_buffer>-total_litres = <ls_buffer>-total_litres + ls_collection-litres.
      <ls_buffer>-round_count = <ls_buffer>-round_count + 1.
      IF ls_collection-collected_on > <ls_buffer>-last_collection.
        <ls_buffer>-last_collection = ls_collection-collected_on.
      ENDIF.
    ENDLOOP.

    rt_settlements = CORRESPONDING #( lt_buffer ).
  ENDMETHOD.

  METHOD normalize.
    rv_restaurant = to_upper( replace( val = iv_restaurant sub = ` ` with = `` occ = 0 ) ).
  ENDMETHOD.
ENDCLASS.