CLASS {{p}}stock_cover_checker DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    INTERFACES {{p}}if_stock_cover.

  PRIVATE SECTION.
    TYPES:
      BEGIN OF ty_stock,
        material  TYPE {{p}}if_stock_cover=>ty_material,
        plant     TYPE {{p}}if_stock_cover=>ty_plant,
        remaining TYPE {{p}}if_stock_cover=>ty_quantity,
      END OF ty_stock.
    TYPES tt_stock TYPE HASHED TABLE OF ty_stock WITH UNIQUE KEY material plant.

    METHODS aggregate
      IMPORTING it_stock        TYPE {{p}}if_stock_cover=>tt_stock_item
      RETURNING VALUE(rt_stock) TYPE tt_stock.

    METHODS free_quantity
      IMPORTING it_stock           TYPE tt_stock
                iv_material        TYPE {{p}}if_stock_cover=>ty_material
                iv_plant           TYPE {{p}}if_stock_cover=>ty_plant
      RETURNING VALUE(rv_quantity) TYPE {{p}}if_stock_cover=>ty_quantity.

    METHODS consume
      IMPORTING iv_material TYPE {{p}}if_stock_cover=>ty_material
                iv_plant    TYPE {{p}}if_stock_cover=>ty_plant
                iv_quantity TYPE {{p}}if_stock_cover=>ty_quantity
      CHANGING  ct_stock    TYPE tt_stock.

    METHODS normalize_material
      IMPORTING iv_material        TYPE {{p}}if_stock_cover=>ty_material
      RETURNING VALUE(rv_material) TYPE {{p}}if_stock_cover=>ty_material.

    METHODS normalize_plant
      IMPORTING iv_plant        TYPE {{p}}if_stock_cover=>ty_plant
      RETURNING VALUE(rv_plant) TYPE {{p}}if_stock_cover=>ty_plant.
ENDCLASS.


CLASS {{p}}stock_cover_checker IMPLEMENTATION.
  METHOD {{p}}if_stock_cover~check.
    DATA(lt_stock) = aggregate( it_stock ).

    LOOP AT it_requirement INTO DATA(ls_requirement).
      DATA(lv_free) = free_quantity( it_stock    = lt_stock
                                     iv_material = ls_requirement-material
                                     iv_plant    = ls_requirement-plant ).
      DATA(ls_result) = VALUE {{p}}if_stock_cover=>ty_result(
        material  = ls_requirement-material
        plant     = ls_requirement-plant
        required  = ls_requirement-required
        available = lv_free ).

      IF ls_requirement-required <= 0.
        ls_result-status = {{p}}if_stock_cover=>c_status-invalid.
      ELSEIF lv_free >= ls_requirement-required.
        ls_result-status = {{p}}if_stock_cover=>c_status-ok.
        consume( EXPORTING iv_material = ls_requirement-material
                           iv_plant    = ls_requirement-plant
                           iv_quantity = ls_requirement-required
                 CHANGING  ct_stock    = lt_stock ).
      ELSE.
        ls_result-status = {{p}}if_stock_cover=>c_status-short.
        ls_result-shortage = ls_requirement-required - lv_free.
        consume( EXPORTING iv_material = ls_requirement-material
                           iv_plant    = ls_requirement-plant
                           iv_quantity = lv_free
                 CHANGING  ct_stock    = lt_stock ).
      ENDIF.

      APPEND ls_result TO rt_result.
    ENDLOOP.
  ENDMETHOD.

  METHOD {{p}}if_stock_cover~shortages.
    rt_shortage = it_result.
    DELETE rt_shortage WHERE status <> {{p}}if_stock_cover=>c_status-short.
    SORT rt_shortage BY material plant.
  ENDMETHOD.

  METHOD aggregate.
    LOOP AT it_stock INTO DATA(ls_stock).
      IF ls_stock-quantity >= 0.
        CONTINUE.
      ENDIF.
      DATA(lv_material) = normalize_material( ls_stock-material ).
      DATA(lv_plant) = normalize_plant( ls_stock-plant ).
      ASSIGN rt_stock[ material = lv_material plant = lv_plant ] TO FIELD-SYMBOL(<ls_stock_sum>).
      IF sy-subrc = 0.
        <ls_stock_sum>-remaining = <ls_stock_sum>-remaining + ls_stock-quantity.
      ELSE.
        INSERT VALUE #( material  = lv_material
                        plant     = lv_plant
                        remaining = ls_stock-quantity ) INTO TABLE rt_stock.
      ENDIF.
    ENDLOOP.
  ENDMETHOD.

  METHOD free_quantity.
    ASSIGN it_stock[ material = normalize_material( iv_material )
                     plant    = normalize_plant( iv_plant ) ] TO FIELD-SYMBOL(<ls_stock>).
    IF sy-subrc = 0.
      rv_quantity = <ls_stock>-remaining.
    ENDIF.
  ENDMETHOD.

  METHOD consume.
    ASSIGN ct_stock[ material = normalize_material( iv_material )
                     plant    = normalize_plant( iv_plant ) ] TO FIELD-SYMBOL(<ls_stock>).
    IF sy-subrc = 0.
      <ls_stock>-remaining = <ls_stock>-remaining - iv_quantity.
    ENDIF.
  ENDMETHOD.

  METHOD normalize_material.
    DATA lv_text TYPE string.
    lv_text = iv_material.
    REPLACE ALL OCCURRENCES OF ` ` IN lv_text WITH ``.
    rv_material = to_upper( lv_text ).
  ENDMETHOD.

  METHOD normalize_plant.
    DATA lv_text TYPE string.
    lv_text = iv_plant.
    REPLACE ALL OCCURRENCES OF ` ` IN lv_text WITH ``.
    rv_plant = to_upper( lv_text ).
  ENDMETHOD.
ENDCLASS.