class ZCL_OS_API definition
  public
  abstract
  final
  create public .

public section.

  type-pools ABAP .
  class-methods SELECT_BY_QUERY
    importing
      !IO_AGENT type ref to IF_OS_CA_PERSISTENCY
      !IS_SELECTION type ANY
      !IV_USE_HASH type ABAP_BOOL default ABAP_TRUE
    exporting
      !ET_DATA type TABLE
    changing
      !CO_TYPE type ref to CL_ABAP_STRUCTDESCR optional
    returning
      value(RT_RESULT) type OSREFTAB .
protected section.
private section.

  types:
    begin of range_ts,
            sign type c length 1,
            option type c length 2,
            low type string,
            high type string,
          end of range_ts .
  types:
    begin of result_ts,
      checksum type MD5_FIELDS-HASH,
      t_result type osreftab,
    end of result_ts .
  types:
    result_tt type hashed table of result_ts with unique key checksum .
  types:
    begin of HASH_TS ,
      agent TYPE REF TO IF_OS_CA_PERSISTENCY,
      t_hash type result_tt,
    end of hash_ts .

  class-data:
    mt_hash type hashed table of HASH_TS with unique key agent .

  class-methods GET_CHECKSUM
    importing
      !IV_SELECTION type ANY
    returning
      value(RV_HASH) type MD5_FIELDS-HASH .
  class-methods GET_QUERY_RANGE_VALUE
    importing
      !IS_RANGE type RANGE_TS
      !IO_EXPR type ref to IF_OS_QUERY_EXPR_FACTORY
      !IV_NAME type STRING
    returning
      value(RO_EXPR) type ref to IF_OS_QUERY_FILTER_EXPR .
  class-methods GET_QUERY_RANGE
    importing
      !IT_RANGE type TABLE
      !IV_NAME type STRING
      !IO_EXPR type ref to IF_OS_QUERY_EXPR_FACTORY
    returning
      value(RO_EXPR) type ref to IF_OS_QUERY_FILTER_EXPR .
  class-methods TO_DATA
    importing
      !IO_OBJECT type ref to IF_SERIALIZABLE_OBJECT
    changing
      !CS_DATA type ANY .
  class-methods IS_RANGE
    importing
      !IO_TYPE type ref to CL_ABAP_TABLEDESCR
    returning
      value(RV_RANGE) type ABAP_BOOL .
  class-methods GET_QUERY
    importing
      !IS_SELECTION type ANY
    changing
      !CO_TYPE type ref to CL_ABAP_STRUCTDESCR optional
    returning
      value(RO_QUERY) type ref to IF_OS_QUERY .
ENDCLASS.



CLASS ZCL_OS_API IMPLEMENTATION.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Private Method ZCL_OS_API=>GET_CHECKSUM
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_SELECTION                   TYPE        ANY
* | [<-()] RV_HASH                        TYPE        MD5_FIELDS-HASH
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method get_checksum.

    try.
        " serialize the request
        call transformation id source request = iv_selection
          result xml data(lv_xml).

        call function 'MD5_CALCULATE_HASH_FOR_RAW'
         EXPORTING
           DATA                 = lv_xml
         IMPORTING
           HASH                 = rv_hash
         EXCEPTIONS
           INTERNAL_ERROR       = 1
           OTHERS               = 2
                  .
        if sy-subrc <> 0.
          " ToDo
        endif.

      catch cx_transformation_error.
        "ToDo
    endtry.


  endmethod.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Private Method ZCL_OS_API=>GET_QUERY
* +-------------------------------------------------------------------------------------------------+
* | [--->] IS_SELECTION                   TYPE        ANY
* | [<-->] CO_TYPE                        TYPE REF TO CL_ABAP_STRUCTDESCR(optional)
* | [<-()] RO_QUERY                       TYPE REF TO IF_OS_QUERY
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method get_query.

    data(lo_query) = cl_os_query_manager=>get_query_manager( )->if_os_query_manager~create_query( ).

    data(lo_expr) = lo_query->get_expr_factory( ).

    if co_type is not bound.
      try.
          co_type = cast #( cl_abap_typedescr=>describe_by_data( is_selection  ) ).
        catch cx_sy_move_cast_error.
          " ToDo: message
          return.
      endtry.

    endif.

    data: lt_and type table of ref to if_os_query_filter_expr.

    " for each selection criteria
    loop at co_type->get_included_view(
*            p_level =
        ) into data(ls_view).

      " parameter or range?
      case ls_view-type->kind.

        " parameter
        when ls_view-type->kind_elem.

          field-symbols: <lv_component> type any.
          unassign <lv_component>.
          assign component ls_view-name of structure is_selection to <lv_component>.
          check <lv_component> is assigned.

          try.

              " goes to and condition
              append
                lo_expr->create_operator_expr(
                    i_attr1                     = ls_view-name
                  i_operator                  = 'EQ'
                  i_val                       = conv #( <lv_component> )
                ) to lt_and.

            catch cx_os_query_expr_fact_error.    "
          endtry.

        when ls_view-type->kind_table.
          " check: is range?
          check is_range( cast #( ls_view-type ) ) eq abap_true.

          " must be not initial
          field-symbols: <lt_range> type table.
          assign component ls_view-name of structure is_selection to <lt_range>.
          check <lt_range> is assigned.
          check <lt_range> is not initial.

          " goes to and condition
          append get_query_range(
            iv_name = ls_view-name
            it_range = <lt_range>
            io_expr = lo_expr )  to lt_and.

      endcase.
    endloop.

    " build and conditions
    loop at lt_and into data(lo_and).
      if sy-tabix eq 1.
        data(lo_filter) = lt_and[ 1 ].
      else.
        lo_filter = lo_expr->create_and_expr(
          exporting
            i_expr1 = lo_filter
            i_expr2 = lo_and
        ).
      endif.
    endloop.

    lo_query->set_filter_expr( lo_filter ).

    ro_query = lo_query.

  endmethod.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Private Method ZCL_OS_API=>GET_QUERY_RANGE
* +-------------------------------------------------------------------------------------------------+
* | [--->] IT_RANGE                       TYPE        TABLE
* | [--->] IV_NAME                        TYPE        STRING
* | [--->] IO_EXPR                        TYPE REF TO IF_OS_QUERY_EXPR_FACTORY
* | [<-()] RO_EXPR                        TYPE REF TO IF_OS_QUERY_FILTER_EXPR
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method get_query_range.

    data: lt_and type table of ref to if_os_query_filter_expr,
          lt_or type table of ref to if_os_query_filter_expr.

    data: ls_range type range_ts.

    " .. for each range value
    loop at it_range assigning field-symbol(<ls_range>).

      move-corresponding exact <ls_range> to ls_range.

      " E = AND, I = OR
      case ls_range-sign.
        when 'E'.

          append io_expr->create_not_expr(
            get_query_range_value(
             is_range = ls_range
             io_expr = io_expr
             iv_name = iv_name ) )  to lt_and..

        when 'I'.
          append get_query_range_value(
            is_range = ls_range
            io_expr = io_expr
            iv_name = iv_name ) to lt_or.
      endcase.

    endloop.

    " First of all combine all OR in to a single expression
    loop at lt_or into data(lo_or).
      if sy-tabix eq 1.
        data(lo_filter_or) = lt_or[ 1 ].
      else.
        lo_filter_or = io_expr->create_or_expr(
          exporting
            i_expr1 = lo_filter_or
            i_expr2 = lo_or
        ).
      endif.
    endloop.

    " make all or statements as one of ANDs
    append lo_filter_or to lt_and.

    loop at lt_and into data(lo_and).
      if sy-tabix eq 1.
        ro_expr = lt_and[ 1 ].
      else.
        ro_expr = io_expr->create_and_expr(
          exporting
            i_expr1 = ro_expr
            i_expr2 = lo_and
        ).
      endif.
    endloop.





  endmethod.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Private Method ZCL_OS_API=>GET_QUERY_RANGE_VALUE
* +-------------------------------------------------------------------------------------------------+
* | [--->] IS_RANGE                       TYPE        RANGE_TS
* | [--->] IO_EXPR                        TYPE REF TO IF_OS_QUERY_EXPR_FACTORY
* | [--->] IV_NAME                        TYPE        STRING
* | [<-()] RO_EXPR                        TYPE REF TO IF_OS_QUERY_FILTER_EXPR
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method get_query_range_value.

    try.

        case is_range-option.

          " is operator
          when
            'EQ' or
            'NE' or
            'LE' or
            'LT' or
            'GE' or
            'GT'
           .

            ro_expr = io_expr->create_operator_expr(
                  i_attr1                     = iv_name
                  i_operator                  = conv #( is_range-option )
                  i_val                       = is_range-low
              ).

          " is mask
          when 'CP'.

            data(lv_pattern) = is_range-low.

            replace all occurrences of '*' in lv_pattern with '%'.

            ro_expr = io_expr->create_like_expr(
              i_attr                      = iv_name
              i_pattern                   = lv_pattern
*              i_not                       = OSCON_FALSE
          ).

          " is mask with not
          when 'NP'.

            lv_pattern = is_range-low.

            replace all occurrences of '*' in lv_pattern with '%'.

            ro_expr = io_expr->create_like_expr(
              i_attr                      = iv_name
              i_pattern                   = lv_pattern
              i_not                       = oscon_true
          ).

*            when 'BT'.

          when others.
            " not supported

        endcase.

      catch cx_os_query_expr_fact_error.  "

    endtry.

  endmethod.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Private Method ZCL_OS_API=>IS_RANGE
* +-------------------------------------------------------------------------------------------------+
* | [--->] IO_TYPE                        TYPE REF TO CL_ABAP_TABLEDESCR
* | [<-()] RV_RANGE                       TYPE        ABAP_BOOL
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method IS_RANGE.

    CHECK io_type->table_kind eq io_type->tablekind_std AND
          io_type->key_defkind eq io_type->KEYDEFKIND_DEFAULT AND
          io_type->key eq value ABAP_KEYDESCR_TAB(
           ( name = 'SIGN')
           ( name = 'OPTION')
           ( name = 'LOW')
           ( name = 'HIGH') ).

    rv_range = abap_true.
  endmethod.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZCL_OS_API=>SELECT_BY_QUERY
* +-------------------------------------------------------------------------------------------------+
* | [--->] IO_AGENT                       TYPE REF TO IF_OS_CA_PERSISTENCY
* | [--->] IS_SELECTION                   TYPE        ANY
* | [--->] IV_USE_HASH                    TYPE        ABAP_BOOL (default =ABAP_TRUE)
* | [<---] ET_DATA                        TYPE        TABLE
* | [<-->] CO_TYPE                        TYPE REF TO CL_ABAP_STRUCTDESCR(optional)
* | [<-()] RT_RESULT                      TYPE        OSREFTAB
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method select_by_query.

    " check agent
    check io_agent is bound.

    try.
        " get hash by agent
        data(lrs_hash) = ref #( mt_hash[ agent = io_agent ] ).
      catch cx_sy_itab_line_not_found.
        " create agent hash
        insert value #( agent = io_agent ) into table mt_hash reference into lrs_hash.
    endtry.

    " read hash
    data(lv_sum) = get_checksum( is_selection ).
    check lv_sum is not initial.

    try.

        rt_result = lrs_hash->t_hash[ checksum = lv_sum ]-t_result.

      catch cx_sy_itab_line_not_found.

        try.
            " get result by using generated method
            rt_result = io_agent->get_persistent_by_query(
              exporting
                " create query by selection criteria
                i_query = get_query(
                  exporting
                    is_selection =  is_selection   " Must be structure
                  changing
                    co_type      = co_type     " Runtime Type Services
                )   " Query
            ).

            " update hash
            insert value #(
              checksum = lv_sum
              t_result = rt_result ) into table lrs_hash->t_hash.

            if et_data is requested.

              try.

                  loop at rt_result into data(lo_result).
                    append initial line to et_data assigning field-symbol(<ls_data>).
                    to_data(
                      exporting
                        io_object = cast #( lo_result )     " Serializable Object
                      changing
                        cs_data   = <ls_data>
                    ).
                  endloop.

                catch cx_sy_move_cast_error.
              endtry.
            endif.

          catch cx_os_object_not_found.    "
          catch cx_os_query_error.    "
        endtry.

    endtry.



  endmethod.


* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Private Method ZCL_OS_API=>TO_DATA
* +-------------------------------------------------------------------------------------------------+
* | [--->] IO_OBJECT                      TYPE REF TO IF_SERIALIZABLE_OBJECT
* | [<-->] CS_DATA                        TYPE        ANY
* +--------------------------------------------------------------------------------------</SIGNATURE>
  method TO_DATA.

     try.

        " Object to asXml:serializable object
        call transformation id
          source struc = io_object
          result xml data(lv_xml).

        " asXml:serializable object to asXml:data
        call transformation zcw_obj2struc
          source xml lv_xml
          result xml data(lv_xml_struc).

        " asXml:data to data
        call transformation id
          source xml lv_xml_struc
          result struct = cs_data.

      catch cx_transformation_error into data(lo_cx).

        if 1 eq 2.
          " here you can go from the debugger
          data(lo_output) = cl_demo_output=>new( ). " <-place the cursor here and press Shift+F12
          lo_output->begin_section( 'Object to asXml:serializable object' ).
          lo_output->write_xml( xml = lv_xml  ).
          lo_output->begin_section( 'asXml:serializable object to asXml:data' ).
          lo_output->write_xml( xml = lv_xml_struc  ).
          lo_output->write_text( lo_cx->get_text( ) ).
          lo_output->display( ).
        endif.

    endtry.

  endmethod.
ENDCLASS.