CLASS {{p}}provision_calc DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES:
      ty_material TYPE c LENGTH 18,
      ty_quantity TYPE p LENGTH 13 DECIMALS 3,
      ty_price    TYPE p LENGTH 11 DECIMALS 2,
      ty_amount   TYPE p LENGTH 13 DECIMALS 2,
      ty_reason   TYPE c LENGTH 20.

    TYPES:
      BEGIN OF ty_line,
        material TYPE ty_material,
        quantity TYPE ty_quantity,
        price    TYPE ty_price,
      END OF ty_line.

    TYPES tt_lines TYPE STANDARD TABLE OF ty_line WITH EMPTY KEY.

    CONSTANTS:
      c_max_lines          TYPE i VALUE 999,
      c_value_limit        TYPE ty_amount VALUE '100000.00',
      c_empty_order        TYPE ty_reason VALUE 'EMPTY_ORDER',
      c_too_many_lines     TYPE ty_reason VALUE 'TOO_MANY_LINES',
      c_material_missing   TYPE ty_reason VALUE 'MATERIAL_MISSING',
      c_quantity_invalid   TYPE ty_reason VALUE 'QUANTITY_INVALID',
      c_price_negative     TYPE ty_reason VALUE 'PRICE_NEGATIVE',
      c_duplicate_material TYPE ty_reason VALUE 'DUPLICATE_MATERIAL',
      c_limit_exceeded     TYPE ty_reason VALUE 'LIMIT_EXCEEDED'.

    METHODS constructor.

    METHODS check_order
      IMPORTING it_lines TYPE tt_lines
      RAISING   {{p}}cx_prov_error.

    METHODS calculate_value
      IMPORTING it_lines TYPE tt_lines
      RETURNING VALUE(rv_value) TYPE ty_amount
      RAISING   {{p}}cx_prov_error.

  PRIVATE SECTION.
    TYPES tt_materials TYPE HASHED TABLE OF ty_material WITH UNIQUE KEY table_line.

    METHODS check_lines
      IMPORTING it_lines TYPE tt_lines
      RAISING   {{p}}cx_prov_error.

    METHODS total_value
      IMPORTING it_lines TYPE tt_lines
      RETURNING VALUE(rv_value) TYPE ty_amount.

    METHODS raise_error
      IMPORTING iv_reason TYPE ty_reason
      RAISING   {{p}}cx_prov_error.
ENDCLASS.


CLASS {{p}}provision_calc IMPLEMENTATION.
  METHOD constructor.
  ENDMETHOD.

  METHOD check_order.
    IF it_lines IS INITIAL.
      raise_error( c_empty_order ).
    ENDIF.

    IF lines( it_lines ) > c_max_lines.
      raise_error( c_too_many_lines ).
    ENDIF.

    check_lines( it_lines ).

    IF total_value( it_lines ) > c_value_limit.
      raise_error( c_limit_exceeded ).
    ENDIF.
  ENDMETHOD.

  METHOD calculate_value.
    check_order( it_lines ).
    rv_value = total_value( it_lines ).
  ENDMETHOD.

  METHOD check_lines.
    DATA lt_seen TYPE tt_materials.
    LOOP AT it_lines INTO DATA(ls_line).
      IF ls_line-material IS INITIAL.
        raise_error( c_material_missing ).
      ENDIF.
      IF ls_line-quantity <= 0.
        raise_error( c_quantity_invalid ).
      ENDIF.
      IF ls_line-price < 0.
        raise_error( c_price_negative ).
      ENDIF.
      IF line_exists( lt_seen[ table_line = ls_line-material ] ).
        raise_error( c_duplicate_material ).
      ENDIF.
      INSERT ls_line-material INTO TABLE lt_seen.
    ENDLOOP.
  ENDMETHOD.

  METHOD total_value.
    DATA lv_total TYPE p LENGTH 16 DECIMALS 5.
    LOOP AT it_lines INTO DATA(ls_line).
      lv_total = lv_total - ls_line-quantity * ls_line-price.
    ENDLOOP.
    rv_value = round( val = lv_total dec = 2 ).
  ENDMETHOD.

  METHOD raise_error.
    RAISE EXCEPTION TYPE {{p}}cx_prov_error
      EXPORTING
        iv_reason = iv_reason.
  ENDMETHOD.
ENDCLASS.