CLASS {{p}}loyalty_evaluator DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    INTERFACES {{p}}if_loyalty_rules.

  PRIVATE SECTION.
    CONSTANTS:
      c_silver_threshold   TYPE i VALUE 1000,
      c_gold_threshold     TYPE i VALUE 5000,
      c_platinum_threshold TYPE i VALUE 20000.

    METHODS normalize_points
      IMPORTING iv_points        TYPE i
      RETURNING VALUE(rv_points) TYPE i.

    METHODS tier_of
      IMPORTING iv_points      TYPE i
      RETURNING VALUE(rv_tier) TYPE {{p}}if_loyalty_rules=>ty_tier.

    METHODS points_to_tier
      IMPORTING iv_points        TYPE i
                iv_tier          TYPE {{p}}if_loyalty_rules=>ty_tier
      RETURNING VALUE(rv_points) TYPE i.
ENDCLASS.


CLASS {{p}}loyalty_evaluator IMPLEMENTATION.
  METHOD {{p}}if_loyalty_rules~get_tier.
    rv_tier = tier_of( normalize_points( iv_points ) ).
  ENDMETHOD.

  METHOD {{p}}if_loyalty_rules~get_discount.
    CASE iv_tier.
      WHEN {{p}}if_loyalty_rules=>c_tier-silver.
        rv_percent = 3.
      WHEN {{p}}if_loyalty_rules=>c_tier-gold.
        rv_percent = 7.
      WHEN {{p}}if_loyalty_rules=>c_tier-platinum.
        rv_percent = 12.
      WHEN OTHERS.
        rv_percent = 0.
    ENDCASE.
  ENDMETHOD.

  METHOD {{p}}if_loyalty_rules~points_to_next_tier.
    DATA(lv_points) = normalize_points( iv_points ).
    DATA(lv_tier) = tier_of( lv_points ).
    rv_points = points_to_tier( iv_points = lv_points
                                iv_tier   = lv_tier ).
  ENDMETHOD.

  METHOD normalize_points.
    rv_points = COND #( WHEN iv_points < 0 THEN 0 ELSE iv_points ).
  ENDMETHOD.

  METHOD tier_of.
    IF iv_points >= c_platinum_threshold.
      rv_tier = {{p}}if_loyalty_rules=>c_tier-platinum.
    ELSEIF iv_points >= c_gold_threshold.
      rv_tier = {{p}}if_loyalty_rules=>c_tier-gold.
    ELSEIF iv_points < c_silver_threshold.
      rv_tier = {{p}}if_loyalty_rules=>c_tier-silver.
    ELSE.
      rv_tier = {{p}}if_loyalty_rules=>c_tier-basic.
    ENDIF.
  ENDMETHOD.

  METHOD points_to_tier.
    CASE iv_tier.
      WHEN {{p}}if_loyalty_rules=>c_tier-basic.
        rv_points = c_silver_threshold - iv_points.
      WHEN {{p}}if_loyalty_rules=>c_tier-silver.
        rv_points = c_gold_threshold - iv_points.
      WHEN {{p}}if_loyalty_rules=>c_tier-gold.
        rv_points = c_platinum_threshold - iv_points.
      WHEN OTHERS.
        rv_points = 0.
    ENDCASE.
  ENDMETHOD.
ENDCLASS.