/**
  @file mv_castabload.sas
  @brief Checks if a CAS table is loaded; if not, loads and promotes it
  @details Runs in SPRE against an active CAS session.  Accepts a
    SAS libref, derives the CAS caslib and session UUID from
    sashelp.vlibnam, then checks whether the table is already
    in-memory.  If not, locates the owning CAS server via the
    casManagement REST API, queries the table endpoint to discover
    the source file and caslib, then loads and promotes the table.

    A CAS session must already be established by the caller, eg:

        cas mysess;
        libname mylib cas caslib=Public;
        %mv_castabload(lib=mylib, table=BASEBALL)

  @param [in] lib=    SAS libref for the CAS caslib
  @param [in] table=  Name of the CAS table to load
  @param [in] mdebug= (0) Set to 1 to enable verbose logging:
                        - echoes resolved parameters
                        - prints tableExists result
                        - enables mprint/notes during PROC calls

  <h4> SAS Macros </h4>
  @li mf_getplatform.sas
  @li mf_getuniquefileref.sas
  @li mf_getuniquelibref.sas
  @li mp_abort.sas

**/

%macro mv_castabload(
    lib=
    ,table=
    ,mdebug=0
);

%local _sysopts base_uri caslib uuid server
      srcfile srccaslib fname1 libref1 ftmp i _svcount _exists;
%let _sysopts=%sysfunc(getoption(mprint)) %sysfunc(getoption(notes));

/* ---- input validation -------------------------------------------------- */
%mp_abort(
  iftrue=("&lib"="" or "&table"=""),
  msg=%str(lib= and table= are required)
)

%if &mdebug=1 %then %do;
  %put &=lib;
  %put &=table;
  options mprint notes;
%end;

/* ---- derive caslib and session UUID from sashelp.vlibnam --------------- */
data _null_;
  set sashelp.vlibnam(
    where=(libname="%upcase(&lib)"
      and sysname in ("Caslib","Session UUID"))
  );
  if sysname="Caslib" then call symputx('caslib',sysvalue,'L');
  else call symputx('uuid',sysvalue,'L');
  %if &mdebug=1 %then %do;
    putlog sysname sysvalue;
  %end;
run;

%mp_abort(
  iftrue=("&caslib"=""),
  msg=%str(&lib is not an assigned CAS libref)
)

%mp_abort(
  iftrue=("&uuid"=""),
  msg=%str(No session UUID found for libref &lib)
)

/* ---- existence check --------------------------------------------------- */
proc cas;
  table.tableExists result=r /
      caslib="&caslib"
      name="&table";
  %if &mdebug=1 %then %do;
    print r;
  %end;
  if r.exists > 0 then call symputx('_exists', '1', 'L');
  else call symputx('_exists', '0', 'L');
quit;

/* ---- already loaded: skip ---------------------------------------------- */
%if &_exists=1 %then %do;
  %put NOTE: Table &caslib..&table already loaded - skipping;
  %return;
%end;

/* ---- get list of CAS servers ----------------------------------------- */
%let base_uri=%mf_getplatform(VIYARESTAPI);
%let fname1=%mf_getuniquefileref();
%let libref1=%mf_getuniquelibref();

proc http method='GET' out=&fname1 oauth_bearer=sas_services
    url="&base_uri/casManagement/servers";
run;

%mp_abort(
  iftrue=(&SYS_PROCHTTP_STATUS_CODE ne 200),
  msg=%str(&SYS_PROCHTTP_STATUS_CODE &SYS_PROCHTTP_STATUS_PHRASE)
)

libname &libref1 JSON fileref=&fname1;

data _null_;
  set &libref1..items;
  call symputx(cats('_sv_', _n_), name, 'L');
  call symputx('_svcount', _n_, 'L');
run;

libname &libref1 clear;
filename &fname1 clear;

/* ---- find which server owns this session ------------------------------ */
%do i=1 %to &_svcount;
  %if "&server"="" %then %do;
    %if &mdebug=1 %then %put checking server: &&_sv_&i;
    %let ftmp=%mf_getuniquefileref();
    proc http method='GET' out=&ftmp oauth_bearer=sas_services
      url="&base_uri/casManagement/servers/&&_sv_&i/sessions/&uuid";
    run;
    %if &SYS_PROCHTTP_STATUS_CODE=200
      %then %let server=&&_sv_&i;
    filename &ftmp clear;
  %end;
%end;

%mp_abort(
  iftrue=("&server"=""),
  msg=%str(Could not find owning server for CAS session &uuid)
)

%if &mdebug=1 %then %put &=server;

/* ---- discover source file from REST endpoint -------------------------- */
%let fname1=%mf_getuniquefileref();
%let libref1=%mf_getuniquelibref();

proc http method='GET' out=&fname1 oauth_bearer=sas_services
  url="&base_uri/casManagement/servers/&server/caslibs/&caslib/tables/&table";
run;

%if &mdebug=1 %then %do;
  %put &=SYS_PROCHTTP_STATUS_CODE &=SYS_PROCHTTP_STATUS_PHRASE;
  data _null_;
    infile &fname1;
    input;
    putlog _infile_;
  run;
%end;

%mp_abort(
  iftrue=(&SYS_PROCHTTP_STATUS_CODE=404),
  msg=%str(&caslib..&table not found - is a source file registered?)
)
%mp_abort(
  iftrue=(&SYS_PROCHTTP_STATUS_CODE ne 200),
  msg=%str(&SYS_PROCHTTP_STATUS_CODE &SYS_PROCHTTP_STATUS_PHRASE)
)

libname &libref1 JSON fileref=&fname1;

data _null_;
  set &libref1..tablereference;
  call symputx('srcfile', sourceTableName, 'L');
  call symputx('srccaslib', sourceCaslibName, 'L');
  stop;
run;

libname &libref1 clear;
filename &fname1 clear;

%mp_abort(
  iftrue=("&srcfile"="" or "&srccaslib"=""),
  msg=%str(No sourceTableName/sourceCaslibName for &caslib..&table)
)

%if &mdebug=1 %then %put &=srcfile &=srccaslib;

/* ---- load from discovered source -------------------------------------- */
proc casutil;
  load casdata="&srcfile"
      incaslib="&srccaslib"
      casout="&table"
      outcaslib="&caslib"
      promote;
quit;

%mp_abort(
  iftrue=(&syscc ne 0),
  msg=%str(Load failed for &caslib..&table)
)

%put NOTE: Table &caslib..&table loaded and promoted from &srcfile;

/* ---- restore options --------------------------------------------------- */
%if &mdebug=1 %then %do;
  options &_sysopts;
%end;

%mend mv_castabload;