/**
  @file mp_getddl.sas
  @brief Extract DDL in various formats, by table or library
  @details Data Definition Language relates to a set of SQL instructions used
    to create tables in SAS or a database.  The macro can be used at table or
    library level.  The default behaviour is to create DDL in SAS format.

  Usage:

      data test(index=(pk=(x y)/unique /nomiss));
        x=1;
        y='blah';
        label x='blah';
      run;
      proc sql; describe table &syslast;

      %mp_getddl(work,test,flavour=tsql,showlog=YES)

  @param lib libref of the library to create DDL for.  Should be assigned.
  @param ds dataset to create ddl for
  @param fref= the fileref to which to write the DDL.  If not preassigned, will
    be assigned to TEMP.
  @param flavour= The type of DDL to create (default=SAS). Supported=TSQL
  @param showlog= Set to YES to show the DDL in the log
  @param schema= Choose a preferred schema name (default is to use actual schema
    ,else libref)
  @param applydttm= for non SAS DDL, choose if columns are created with native
   datetime2 format or regular decimal type

  @version 9.3
  @author Allan Bowe
  @source https://github.com/sasjs/core

**/

%macro mp_getddl(libref,ds,fref=getddl,flavour=SAS,showlog=NO,schema=
  ,applydttm=NO
)/*/STORE SOURCE*/;

/* check fileref is assigned */
%if %sysfunc(fileref(&fref)) > 0 %then %do;
  filename &fref temp;
%end;
%if %length(&libref)=0 %then %let libref=WORK;
%let flavour=%upcase(&flavour);

proc sql noprint;
create table _data_ as
  select * from dictionary.tables
  where upcase(libname)="%upcase(&libref)"
  %if %length(&ds)>0 %then %do;
    and upcase(memname)="%upcase(&ds)"
  %end;
  ;
%local tabinfo; %let tabinfo=&syslast;

create table _data_ as
  select * from dictionary.indexes
  where upcase(libname)="%upcase(&libref)"
  %if %length(&ds)>0 %then %do;
    and upcase(memname)="%upcase(&ds)"
  %end;
  order by idxusage, indxname, indxpos
  ;
%local idxinfo; %let idxinfo=&syslast;

create table _data_ as
  select * from dictionary.columns
  where upcase(libname)="%upcase(&libref)"
  %if %length(&ds)>0 %then %do;
    and upcase(memname)="%upcase(&ds)"
  %end;
  ;
%local colinfo; %let colinfo=&syslast;
%local dsnlist;
select distinct upcase(memname) into: dsnlist
  separated by ' '
  from &syslast;
data _null_;
  file &fref;
  put "/* DDL generated by &sysuserid on %sysfunc(datetime(),datetime19.) */";
run;

%local x curds;
%if &flavour=SAS %then %do;
  data _null_;
    file &fref;
    put "proc sql;";
  run;
  %do x=1 %to %sysfunc(countw(&dsnlist));
    %let curds=%scan(&dsnlist,&x);
    data _null_;
      file &fref mod;
      length nm lab $1024;
      set &colinfo (where=(upcase(memname)="&curds")) end=last;

      if _n_=1 then do;
        if memtype='DATA' then do;
          put "create table &libref..&curds(";
        end;
        else do;
          put "create view &libref..&curds(";
        end;
        put "    "@@;
      end;
      else put "   ,"@@;
      if length(format)>1 then fmt=" format="!!cats(format);
      len=" length="!!cats(length);
      lab=" label="!!quote(trim(label));
      if notnull='yes' then notnul=' not null';
      put name type len fmt notnul lab;
      if last then put ');';
    run;

    data _null_;
      length ds $128;
      set &idxinfo (where=(memname="&curds")) end=last;
      file &fref mod;
      by idxusage indxname;
      if unique='yes' then uniq=' unique';
      ds=cats(libname,'.',memname);
      if first.indxname then do;
        put 'create ' uniq ' index ' indxname;
        put '  on ' ds '(' name @@;
      end;
      else put ',' name @@;
      if last.indxname then put ');';
    run;
/*
    ods output IntegrityConstraints=ic;
    proc contents data=testali out2=info;
    run;
    */
  %end;
%end;
%else %if &flavour=TSQL %then %do;
  /* if schema does not exist, set to be same as libref */
  %local schemaactual;
  proc sql noprint;
  select sysvalue into: schemaactual
    from dictionary.libnames
    where libname="&libref" and engine='SQLSVR';
  %let schema=%sysfunc(coalescec(&schemaactual,&schema,&libref));

  %do x=1 %to %sysfunc(countw(&dsnlist));
    %let curds=%scan(&dsnlist,&x);
    data _null_;
      file &fref mod;
      put "/* DDL for &schema..&curds */";
    data _null_;
      file &fref mod;
      set &colinfo (where=(upcase(memname)="&curds")) end=last;
      if _n_=1 then do;
        if memtype='DATA' then do;
          put "create table [&schema].[&curds](";
        end;
        else do;
          put "create view [&schema].[&curds](";
        end;
        put "    "@@;
      end;
      else put "   ,"@@;
      format=upcase(format);
      if 1=0 then; /* dummy if */
      %if &applydttm=YES %then %do;
        else if format=:'DATETIME' then fmt='[datetime2](7)  ';
      %end;
      else if type='num' then fmt='[decimal](18,2)';
      else if length le 8000 then fmt='[varchar]('!!cats(length)!!')';
      else fmt=cats('[varchar](max)');
      if notnull='yes' then notnul=' NOT NULL';
      put name fmt notnul;
    run;
    data _null_;
      length ds $128;
      set &idxinfo (where=(memname="&curds"));
      file &fref mod;
      by idxusage indxname;
      if unique='yes' then uniq=' unique';
      ds=cats(libname,'.',memname);
      if first.indxname then do;
        if unique='yes' and nomiss='yes' then do;
          put '  ,constraint [' indxname '] PRIMARY KEY';
        end;
        else if unique='yes' then do;
          /* add nonclustered in case of multiple unique indexes */
          put '  ,index [' indxname '] UNIQUE NONCLUSTERED';
        end;
        put '  (';
        put '    [' name ']';
      end;
      else put '    ,[' name ']';
      if last.indxname then do;
        put '  )';
      end;
    run;
    data _null_;
      file &fref mod;
      put ')';
      put 'GO';
    run;

    /* add extended properties for labels */
    data _null_;
      file &fref mod;
      length nm $64 lab $1024;
      set &colinfo (where=(upcase(memname)="&curds" and label ne '')) end=last;
      nm=cats("N'",tranwrd(name,"'","''"),"'");
      lab=cats("N'",tranwrd(label,"'","''"),"'");
      put ' ';
      put "EXEC sys.sp_addextendedproperty ";
      put "  @name=N'MS_Description',@value=" lab ;
      put "  ,@level0type=N'SCHEMA',@level0name=N'&schema' ";
      put "  ,@level1type=N'TABLE',@level1name=N'&curds'";
      put "  ,@level2type=N'COLUMN',@level2name=" nm ;
      if last then put 'GO';
    run;
  %end;
%end;
%else %if &flavour=PGSQL %then %do;
  /* if schema does not exist, set to be same as libref */
  %local schemaactual;
  proc sql noprint;
  select sysvalue into: schemaactual
    from dictionary.libnames
    where libname="&libref" and engine='POSTGRES';
  %let schema=%sysfunc(coalescec(&schemaactual,&schema,&libref));

  %do x=1 %to %sysfunc(countw(&dsnlist));
    %let curds=%scan(&dsnlist,&x);
    data _null_;
      file &fref mod;
      put "/* Postgres Flavour DDL for &schema..&curds */";
    data _null_;
      file &fref mod;
      set &colinfo (where=(upcase(memname)="&curds")) end=last;
      length fmt $32;
      if _n_=1 then do;
        if memtype='DATA' then do;
          put "CREATE TABLE &schema..&curds (";
        end;
        else do;
          put "CREATE VIEW &schema..&curds (";
        end;
        put "    "@@;
      end;
      else put "   ,"@@;
      format=upcase(format);
      if 1=0 then; /* dummy if */
      %if &applydttm=YES %then %do;
        else if format=:'DATETIME' then fmt=' TIMESTAMP ';
      %end;
      else if type='num' then fmt=' DOUBLE PRECISION';
      else fmt='VARCHAR('!!cats(length)!!')';
      if notnull='yes' then notnul=' NOT NULL';
      put name fmt notnul;
    run;
    data _null_;
      length ds $128;
      set &idxinfo (where=(memname="&curds"));
      file &fref mod;
      by idxusage indxname;
      if unique='yes' then uniq=' unique';
      ds=cats(libname,'.',memname);
      if first.indxname then do;
        if unique='yes' and nomiss='yes' then do;
          put '  ,PRIMARY KEY ';
        end;
        else if unique='yes' then do;
          /* add nonclustered in case of multiple unique indexes */
          put '  ,UNIQUE ';
        end;
        put '  (' name ;
      end;
      else put '    ,' name ;
      if last.indxname then do;
        put '  )';
      end;
    run;
    data _null_;
      file &fref mod;
      put ');';
    run;
  %end;
%end;
%if &showlog=YES %then %do;
  options ps=max;
  data _null_;
    infile &fref;
    input;
    putlog _infile_;
  run;
%end;

%mend;