CLASS {{p}}soil_evaluator DEFINITION PUBLIC FINAL CREATE PUBLIC.
  PUBLIC SECTION.
    TYPES:
      ty_ph       TYPE p LENGTH 3 DECIMALS 1,
      ty_nutrient TYPE i,
      ty_status   TYPE c LENGTH 1,
      ty_grade    TYPE c LENGTH 1,
      BEGIN OF ty_sample,
        ph       TYPE ty_ph,
        nutrient TYPE ty_nutrient,
      END OF ty_sample,
      tt_sample TYPE STANDARD TABLE OF ty_sample WITH EMPTY KEY,
      BEGIN OF ty_result,
        status       TYPE ty_status,
        avg_ph       TYPE ty_ph,
        avg_nutrient TYPE ty_nutrient,
        grade        TYPE ty_grade,
      END OF ty_result.
    CONSTANTS:
      c_status_ok    TYPE ty_status VALUE 'O',
      c_status_error TYPE ty_status VALUE 'E',
      c_grade_a      TYPE ty_grade VALUE 'A',
      c_grade_b      TYPE ty_grade VALUE 'B',
      c_grade_c      TYPE ty_grade VALUE 'C'.
    METHODS evaluate
      IMPORTING it_samples TYPE tt_sample
      RETURNING VALUE(rs_result) TYPE ty_result.
  PRIVATE SECTION.
    CONSTANTS:
      c_ph_min     TYPE ty_ph VALUE '0.0',
      c_ph_max     TYPE ty_ph VALUE '14.0',
      c_ph_a_min   TYPE ty_ph VALUE '6.0',
      c_ph_a_max   TYPE ty_ph VALUE '7.5',
      c_ph_b_min   TYPE ty_ph VALUE '5.0',
      c_ph_b_max   TYPE ty_ph VALUE '8.0',
      c_nutr_a_min TYPE ty_nutrient VALUE 50,
      c_nutr_b_min TYPE ty_nutrient VALUE 30.
    METHODS has_invalid_ph
      IMPORTING it_samples TYPE tt_sample
      RETURNING VALUE(rv_invalid) TYPE abap_bool.
    METHODS average_ph
      IMPORTING it_samples TYPE tt_sample
      RETURNING VALUE(rv_avg) TYPE ty_ph.
    METHODS average_nutrient
      IMPORTING it_samples TYPE tt_sample
      RETURNING VALUE(rv_avg) TYPE ty_nutrient.
    METHODS determine_grade
      IMPORTING iv_avg_ph       TYPE ty_ph
                iv_avg_nutrient TYPE ty_nutrient
      RETURNING VALUE(rv_grade) TYPE ty_grade.
ENDCLASS.

CLASS {{p}}soil_evaluator IMPLEMENTATION.
  METHOD evaluate.
    IF it_samples IS INITIAL.
      rs_result-status = c_status_error.
      RETURN.
    ENDIF.
    IF has_invalid_ph( it_samples ) = abap_true.
      rs_result-status = c_status_error.
      RETURN.
    ENDIF.
    rs_result-avg_ph = average_ph( it_samples ).
    rs_result-avg_nutrient = average_nutrient( it_samples ).
    rs_result-grade = determine_grade( iv_avg_ph = rs_result-avg_ph
                                       iv_avg_nutrient = rs_result-avg_nutrient ).
    rs_result-status = c_status_ok.
  ENDMETHOD.

  METHOD has_invalid_ph.
    LOOP AT it_samples INTO DATA(ls_sample).
      IF ls_sample-ph < c_ph_min OR ls_sample-ph > c_ph_max.
        rv_invalid = abap_true.
        RETURN.
      ENDIF.
    ENDLOOP.
  ENDMETHOD.

  METHOD average_ph.
    DATA lv_sum TYPE p LENGTH 9 DECIMALS 1.
    LOOP AT it_samples INTO DATA(ls_sample).
      lv_sum = lv_sum + ls_sample-ph.
    ENDLOOP.
    rv_avg = lv_sum / lines( it_samples ).
  ENDMETHOD.

  METHOD average_nutrient.
    DATA lv_sum TYPE i.
    LOOP AT it_samples INTO DATA(ls_sample).
      lv_sum = lv_sum + ls_sample-nutrient.
    ENDLOOP.
    rv_avg = lv_sum / lines( it_samples ).
  ENDMETHOD.

  METHOD determine_grade.
    IF iv_avg_ph >= c_ph_a_min AND iv_avg_ph <= c_ph_a_max
       AND iv_avg_nutrient >= c_nutr_a_min.
      rv_grade = c_grade_a.
    ELSEIF iv_avg_ph >= c_ph_b_min AND iv_avg_ph <= c_ph_b_max
           AND iv_avg_nutrient >= c_nutr_b_min.
      rv_grade = c_grade_b.
    ELSE.
      rv_grade = c_grade_c.
    ENDIF.
  ENDMETHOD.
ENDCLASS.