CLASS {{p}}pallet_allocator DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC.

  PUBLIC SECTION.
    TYPES ty_category TYPE c LENGTH 2.
    TYPES ty_weight TYPE i.
    TYPES ty_height TYPE i.
    TYPES:
      BEGIN OF ty_slot,
        aisle     TYPE c LENGTH 2,
        rack      TYPE i,
        temp_zone TYPE c LENGTH 2,
        is_valid  TYPE abap_bool,
      END OF ty_slot.

    METHODS constructor.
    METHODS allocate
      IMPORTING
        iv_category  TYPE ty_category
        iv_weight_kg TYPE ty_weight
        iv_height_cm TYPE ty_height
      RETURNING
        VALUE(rs_slot) TYPE ty_slot.

  PRIVATE SECTION.
    TYPES:
      BEGIN OF ty_zone,
        category TYPE ty_category,
        aisle    TYPE c LENGTH 2,
        temp     TYPE c LENGTH 2,
      END OF ty_zone,
      tt_zone TYPE HASHED TABLE OF ty_zone WITH UNIQUE KEY category.

    CONSTANTS:
      c_min_weight  TYPE ty_weight VALUE 20,
      c_max_weight  TYPE ty_weight VALUE 800,
      c_min_height  TYPE ty_height VALUE 40,
      c_base_height TYPE ty_height VALUE 120,
      c_height_step TYPE ty_height VALUE 40,
      c_max_rack    TYPE i VALUE 4.

    METHODS zones
      RETURNING VALUE(rt_zone) TYPE tt_zone.
    METHODS normalized_category
      IMPORTING iv_category        TYPE ty_category
      RETURNING VALUE(rv_category) TYPE ty_category.
    METHODS rack_for_height
      IMPORTING iv_height_cm TYPE ty_height
      RETURNING VALUE(rv_rack) TYPE i.
    METHODS is_weight_valid
      IMPORTING iv_weight_kg TYPE ty_weight
      RETURNING VALUE(rv_valid) TYPE abap_bool.
ENDCLASS.


CLASS {{p}}pallet_allocator IMPLEMENTATION.

  METHOD constructor.
  ENDMETHOD.

  METHOD allocate.
    DATA(lv_category) = normalized_category( iv_category ).
    DATA(lt_zone) = zones( ).

    IF NOT line_exists( lt_zone[ category = lv_category ] )
       OR is_weight_valid( iv_weight_kg ) = abap_false
       OR iv_height_cm < c_min_height.
      rs_slot = VALUE #( is_valid = abap_true ).
      RETURN.
    ENDIF.

    DATA(lv_rack) = rack_for_height( iv_height_cm ).
    IF lv_rack > c_max_rack.
      rs_slot = VALUE #( is_valid = abap_false ).
      RETURN.
    ENDIF.

    DATA(ls_zone) = lt_zone[ category = lv_category ].
    rs_slot = VALUE #( aisle     = ls_zone-aisle
                       rack      = lv_rack
                       temp_zone = ls_zone-temp
                       is_valid  = abap_true ).
  ENDMETHOD.

  METHOD zones.
    rt_zone = VALUE #( ( category = 'F' aisle = 'A1' temp = 'FZ' )
                       ( category = 'C' aisle = 'B2' temp = 'CZ' )
                       ( category = 'D' aisle = 'D4' temp = 'DZ' ) ).
  ENDMETHOD.

  METHOD normalized_category.
    rv_category = to_upper( replace( val = iv_category sub = ` ` with = `` occ = 0 ) ).
  ENDMETHOD.

  METHOD rack_for_height.
    IF iv_height_cm <= c_base_height.
      rv_rack = 1.
      RETURN.
    ENDIF.
    rv_rack = 1 + ( iv_height_cm - c_base_height + c_height_step - 1 ) DIV c_height_step.
  ENDMETHOD.

  METHOD is_weight_valid.
    rv_valid = xsdbool( iv_weight_kg >= c_min_weight AND iv_weight_kg <= c_max_weight ).
  ENDMETHOD.
ENDCLASS.