#include "btree_gist.h"
#include "utils/pg_locale.h"
#include "btree_utils_var.h"

/* Returns a better readable representaion of variable key ( sets pointer ) */

extern GBT_VARKEY_R gbt_var_key_readable ( const GBT_VARKEY * k ){

        GBT_VARKEY_R    r ;
        r.lower   = ( bytea * ) &(((char*)k)[VARHDRSZ] ) ;
        if ( VARSIZE(k) > ( VARHDRSZ+(VARSIZE(r.lower)) ) )
          r.upper = ( bytea * ) &(((char*)k)[VARHDRSZ+INTALIGN(VARSIZE(r.lower))] ) ;
        else
          r.upper = r.lower;
        return r;
}


extern GBT_VARKEY * gbt_var_key_copy ( const GBT_VARKEY_R * u , bool force_node ){

        GBT_VARKEY * r = NULL;

        if ( u->lower == u->upper && !force_node ){  /* leaf key mode */

          r = (GBT_VARKEY *) palloc(VARSIZE(u->lower) + VARHDRSZ );
          memcpy ( (void*) VARDATA(r), (void*) u->lower , VARSIZE(u->lower) );
          r->vl_len = VARSIZE(u->lower) + VARHDRSZ ;

        } else {                     /* node key mode  */

          r = (GBT_VARKEY *) palloc(INTALIGN(VARSIZE(u->lower)) + VARSIZE(u->upper) + VARHDRSZ );
          memcpy ( (void*) VARDATA(r)                               , (void*) u->lower , VARSIZE(u->lower) );
          memcpy ( (void*)&(((char *)r)[VARHDRSZ+INTALIGN(VARSIZE(u->lower))]), (void*) u->upper , VARSIZE(u->upper) );
          r->vl_len    = INTALIGN(VARSIZE(u->lower)) + VARSIZE(u->upper) + VARHDRSZ ;

        }
        return r;

}


static GBT_VARKEY * gbt_var_leaf2node ( GBT_VARKEY * leaf, const gbtree_vinfo * tinfo )
{

  GBT_VARKEY   *out = leaf ;

  if ( tinfo->f_l2n )
  {
    out = (*tinfo->f_l2n) (leaf);
  }

  return out;

}


/*
 * returns the common prefix length of a node key
*/
static int32 gbt_var_node_cp_len ( const GBT_VARKEY * node , const gbtree_vinfo * tinfo )
{
  int32        i ;
  int32        s = (tinfo->str)?(1):(0);
  GBT_VARKEY_R r = gbt_var_key_readable ( node );
  int32   t1len  = VARSIZE(r.lower) - VARHDRSZ - s;
  int32   t2len  = VARSIZE(r.upper) - VARHDRSZ - s;
  int32   ml     = Min(t1len,t2len) ;

  char      * p1 = VARDATA(r.lower) ,
            * p2 = VARDATA(r.upper) ;

  for ( i=0 ; i<ml; i++ )
  {
    if ( *p1 != *p2   )
    {
      return i;
    }
    p1++;
    p2++;
  }
  return ( ml );
}



/*
 * returns true, if query matches prefix using common prefix
*/

static bool gbt_bytea_pf_match ( const bytea * pf , const bytea * query , const gbtree_vinfo * tinfo )
{

  int k  ;
  int32     s = (tinfo->str)?(1):(0);
  bool out    = FALSE ;
  int32  qlen = VARSIZE(query) - VARHDRSZ - s ;
  int32  nlen = VARSIZE(pf)    - VARHDRSZ - s ;
  if ( nlen <= qlen )
  {
    char     *q  = VARDATA(query) ;
    char     *n  = VARDATA(pf) ;
    out = TRUE;
    for ( k=0 ; k<nlen; k++ )
    {
      if ( *n != *q   ){
        out = FALSE;
        break;
      }
      if ( k < (nlen-1) )
      {
        q++;
        n++;
      }
    }
  }

  return out;
}




/*
 * returns true, if query matches node using common prefix
*/

static bool gbt_var_node_pf_match ( const GBT_VARKEY_R * node , const bytea * query , const gbtree_vinfo * tinfo )
{

  return (
    gbt_bytea_pf_match ( node->lower, query , tinfo ) ||
    gbt_bytea_pf_match ( node->upper, query , tinfo )
  );

}


/*
*  truncates / compresses the node key
*/
static GBT_VARKEY * gbt_var_node_truncate ( const GBT_VARKEY * node , int32 length , const gbtree_vinfo * tinfo )
{

  int32          s = (tinfo->str)?(1):(0);
  GBT_VARKEY * out = NULL;  
  GBT_VARKEY_R   r = gbt_var_key_readable ( node );
  int32 len1       = VARSIZE(r.lower) - VARHDRSZ;
  int32 len2       = VARSIZE(r.upper) - VARHDRSZ;
  int32 si         = 0;

  if (tinfo->str)
    length++; /* because of tailing '\0' */

  len1        = Min( len1, length ) ;
  len2        = Min( len2, length ) ;
  si          = 2*VARHDRSZ + INTALIGN(VARHDRSZ+len1) + len2;
  out         = (GBT_VARKEY *) palloc ( si );
  out->vl_len = si;
  memcpy ( (void*) &(((char*)out)[VARHDRSZ])         , (void*)r.lower, len1+VARHDRSZ-s );
  memcpy ( (void*) &(((char*)out)[VARHDRSZ+INTALIGN(VARHDRSZ+len1)])  , (void*)r.upper, len2+VARHDRSZ-s );

  if (tinfo->str)
  {
    ((char*)out)[VARHDRSZ+INTALIGN(VARHDRSZ+len1)-1]               = '\0';
    ((char*)out)[2*VARHDRSZ+INTALIGN(VARHDRSZ+len1)+len2-1]          = '\0';
  }
  *((int32*)&(((char*)out)[VARHDRSZ]))          = len1 + VARHDRSZ;
  *((int32*)&(((char*)out)[VARHDRSZ+INTALIGN(VARHDRSZ+len1)]))   = len2 + VARHDRSZ;

  return out;
}



extern void
gbt_var_bin_union ( Datum * u , GBT_VARKEY * e , const gbtree_vinfo * tinfo )         
{

     GBT_VARKEY   * nk = NULL;
     GBT_VARKEY  * tmp = NULL;
     GBT_VARKEY_R   nr ;
     GBT_VARKEY_R   eo = gbt_var_key_readable ( e );


     if ( eo.lower == eo.upper ) /* leaf */
     {
        tmp = gbt_var_leaf2node ( e , tinfo );
        if ( tmp != e )
          eo  = gbt_var_key_readable ( tmp );
     }

     if ( DatumGetPointer(*u))
     {

       GBT_VARKEY_R ro  = gbt_var_key_readable ( ( GBT_VARKEY *) DatumGetPointer (*u) );

       if ( (*tinfo->f_cmp) ( (bytea*)ro.lower, (bytea*)eo.lower ) > 0 ) {
         nr.lower = eo.lower;
         nr.upper = ro.upper;
         nk       = gbt_var_key_copy ( &nr, TRUE );
       }
       if ( (*tinfo->f_cmp) ( (bytea*)ro.upper, (bytea*)eo.upper ) < 0 ) {
         nr.upper = eo.upper;
         nr.lower = ro.lower;
         nk       = gbt_var_key_copy ( &nr, TRUE );
       }
       if ( nk )
       {
         pfree( DatumGetPointer (*u) );
         *u = PointerGetDatum(nk);
       }



     }
     else
     {
       nr.lower = eo.lower;
       nr.upper = eo.upper;
       *u  = PointerGetDatum( gbt_var_key_copy ( &nr, TRUE ) );
     }

     if ( tmp && tmp != e )
       pfree ( tmp );

}



extern GISTENTRY  *
gbt_var_compress ( GISTENTRY *entry , const gbtree_vinfo * tinfo )
{

        GISTENTRY * retval;

        if (entry->leafkey)
        {
            GBT_VARKEY * r = NULL;
            bytea * tstd = ( bytea * ) DatumGetPointer ( entry->key );                        /* toasted   */
            bytea * leaf = ( bytea * ) DatumGetPointer ( PG_DETOAST_DATUM ( entry->key ) );   /* untoasted */
            GBT_VARKEY_R  u ;

            u.lower     = u.upper = leaf;           
            r           = gbt_var_key_copy ( &u , FALSE );

            if ( tstd != leaf ){
              pfree(leaf);
            }
            retval      = palloc(sizeof(GISTENTRY));
            gistentryinit(*retval, PointerGetDatum(r),
                   entry->rel, entry->page,
                   entry->offset, VARSIZE(r), TRUE);
        } else {
          retval = entry;


        }

        return (retval);
}



extern GBT_VARKEY *
gbt_var_union ( const GistEntryVector * entryvec , int32  * size , const gbtree_vinfo * tinfo )
{

    int        i = 0,
    numranges = entryvec->n;
    GBT_VARKEY   *cur,
                 *tst=NULL;
    Datum         out;
    GBT_VARKEY_R   rk;

    *size = sizeof(GBT_VARKEY);

    tst = (GBT_VARKEY *) DatumGetPointer((entryvec->vector[0].key));
    cur = (GBT_VARKEY *) DatumGetPointer(PG_DETOAST_DATUM((entryvec->vector[0].key)));
    rk  = gbt_var_key_readable ( cur );
    out = PointerGetDatum ( gbt_var_key_copy( &rk, TRUE ) );
    if ( tst != cur ) pfree ( cur );

    for (i = 1; i < numranges; i++)
    {
       tst = (GBT_VARKEY *) DatumGetPointer((entryvec->vector[i].key));
       cur = (GBT_VARKEY *) DatumGetPointer(PG_DETOAST_DATUM((entryvec->vector[i].key)));
       gbt_var_bin_union ( &out , cur , tinfo );
       if ( tst != cur ) pfree ( cur );
    }


    /* Truncate (=compress) key */

    if ( tinfo->trnc )
    {
      int32       plen ;
      GBT_VARKEY  *trc = NULL;

      plen = gbt_var_node_cp_len   ( (GBT_VARKEY *) DatumGetPointer(out) , tinfo );
      trc  = gbt_var_node_truncate ( (GBT_VARKEY *) DatumGetPointer(out) , plen+1 , tinfo ) ;

      pfree ( DatumGetPointer(out) );
      out  = PointerGetDatum ( trc );
    }

    return ( (GBT_VARKEY *) DatumGetPointer ( out ) );
}


extern bool gbt_var_same ( bool * result, const Datum d1 , const Datum d2 , const gbtree_vinfo * tinfo ){

        GBT_VARKEY      *tst1   = (GBT_VARKEY *) DatumGetPointer(d1);
        GBT_VARKEY      *t1     = (GBT_VARKEY *) DatumGetPointer( PG_DETOAST_DATUM(d1) );
        GBT_VARKEY      *tst2   = (GBT_VARKEY *) DatumGetPointer(d2);
        GBT_VARKEY      *t2     = (GBT_VARKEY *) DatumGetPointer( PG_DETOAST_DATUM(d2) );
        GBT_VARKEY_R r1, r2;
        r1 = gbt_var_key_readable ( t1 );
        r2 = gbt_var_key_readable ( t2 );

        if (t1 && t2){
                *result = ( ( (*tinfo->f_cmp ) ( (bytea*)r1.lower, (bytea*)r2.lower) == 0 
                              && (*tinfo->f_cmp) ( (bytea*)r1.upper, (bytea*)r2.upper) == 0 ) ? TRUE : FALSE );
        } else
                *result = (t1 == NULL && t2 == NULL) ? TRUE : FALSE;

        if ( tst1 != t1 ) pfree (t1);
        if ( tst2 != t2 ) pfree (t2);

        PG_RETURN_POINTER(result);
}



extern float *
gbt_var_penalty ( float * res , const GISTENTRY * o , const GISTENTRY * n, const gbtree_vinfo * tinfo )
{

   GBT_VARKEY    *orgt  = (GBT_VARKEY *) DatumGetPointer(o->key);
   GBT_VARKEY    *orge  = (GBT_VARKEY *) DatumGetPointer( PG_DETOAST_DATUM(o->key) );
   GBT_VARKEY    *newt  = (GBT_VARKEY *) DatumGetPointer(n->key);
   GBT_VARKEY    *newe  = (GBT_VARKEY *) DatumGetPointer( PG_DETOAST_DATUM(n->key) );
   GBT_VARKEY_R  ok , nk;
   GBT_VARKEY      *tmp = NULL;
   int32              s = (tinfo->str)?(1):(0);

   *res = 0.0;

   nk  = gbt_var_key_readable ( newe );
   if ( nk.lower == nk.upper ) /* leaf */
   {
      tmp = gbt_var_leaf2node    ( newe , tinfo );
      if ( tmp != newe )
        nk  = gbt_var_key_readable ( tmp  );
   }
   ok  = gbt_var_key_readable ( orge );

   if ( ( VARSIZE(ok.lower) - VARHDRSZ ) == s && ( VARSIZE(ok.upper) - VARHDRSZ ) == s )
   {
     *res = 0.0;
   } else
   if ( ! (
     (
        ( (*tinfo->f_cmp) (nk.lower, ok.lower)>=0 || gbt_bytea_pf_match(ok.lower, nk.lower, tinfo ) ) &&
        ( (*tinfo->f_cmp) (nk.upper, ok.upper)<=0 || gbt_bytea_pf_match(ok.upper, nk.upper, tinfo ) )
     )
   ) )
   {
      Datum     d = PointerGetDatum (0);
      double dres = 0.0;
      int32 ol, ul;

      gbt_var_bin_union ( &d , orge , tinfo );
      ol = gbt_var_node_cp_len ( ( GBT_VARKEY *) DatumGetPointer(d), tinfo );
      gbt_var_bin_union ( &d , newe , tinfo );
      ul = gbt_var_node_cp_len ( ( GBT_VARKEY *) DatumGetPointer(d), tinfo );

      if ( ul < ol ) {
        dres = ( ol-ul ) ; /* lost of common prefix len */
      } else {
        GBT_VARKEY_R uk = gbt_var_key_readable ( ( GBT_VARKEY *) DatumGetPointer(d) );
        if ( tinfo->str )
        {
          dres = ( VARDATA(ok.lower)[ul]-VARDATA(uk.lower)[ul] ) +
                 ( VARDATA(uk.upper)[ul]-VARDATA(ok.upper)[ul] );
        } else {
          char tmp[4];
          tmp[0] = ( ( VARSIZE(ok.lower) - VARHDRSZ ) == ul  )?(CHAR_MIN):(VARDATA(ok.lower)[ul]);
          tmp[1] = ( ( VARSIZE(uk.lower) - VARHDRSZ ) == ul  )?(CHAR_MIN):(VARDATA(uk.lower)[ul]);
          tmp[2] = ( ( VARSIZE(ok.upper) - VARHDRSZ ) == ul  )?(CHAR_MIN):(VARDATA(ok.upper)[ul]);
          tmp[3] = ( ( VARSIZE(uk.upper) - VARHDRSZ ) == ul  )?(CHAR_MIN):(VARDATA(uk.upper)[ul]);
          dres = ( tmp[0] - tmp[1] ) +
                 ( tmp[3] - tmp[2] );
        }
        dres /= 256.0;
      }
      pfree ( DatumGetPointer(d) );

      *res += FLT_MIN ;
      *res += (float) ( dres / ( (double) ( ol +1 ) ) );
      *res *= ( FLT_MAX / ( o->rel->rd_att->natts + 1 ) );

   }

   if ( tmp && tmp != newe )
     pfree (tmp);

   if ( newe != newt ){
     pfree ( newe );
   }

   if ( orge != orgt ){
     pfree ( orge );
   }
   return res ;

}


/*
 * Fortunately, this sort comparsion routine needn't be reentrant...
 */
static const gbtree_vinfo * gbt_vsrt_cmp_tinfo;

static int
gbt_vsrt_cmp(const void *a, const void *b)
{
	GBT_VARKEY_R    ar  = gbt_var_key_readable ( ((const Vsrt *) a)->t );
	GBT_VARKEY_R    br  = gbt_var_key_readable ( ((const Vsrt *) b)->t );

	return (*gbt_vsrt_cmp_tinfo->f_cmp) ( ar.lower, br.lower );
}

extern GIST_SPLITVEC *
gbt_var_picksplit( const GistEntryVector *entryvec, GIST_SPLITVEC *v, const gbtree_vinfo * tinfo )
{
    OffsetNumber  i,
		maxoff    = entryvec->n - 1;
    Vsrt     *arr;
    int       pfrcntr = 0 ,
              svcntr  = 0 , 
              nbytes  ;   
    char        * tst ,
                * cur ;
    char       **pfr = NULL ;
    GBT_VARKEY **sv  = NULL;

	arr = (Vsrt *) palloc((maxoff+1) * sizeof(Vsrt));
    nbytes        = (maxoff + 2) * sizeof(OffsetNumber);
    v->spl_left   = (OffsetNumber *) palloc(nbytes);
    v->spl_right  = (OffsetNumber *) palloc(nbytes);   
    v->spl_ldatum = PointerGetDatum(0);
    v->spl_rdatum = PointerGetDatum(0);
    v->spl_nleft  = 0;
    v->spl_nright = 0; 

    pfr = palloc ( sizeof ( GBT_VARKEY* ) * (maxoff+1) );
    sv  = palloc ( sizeof ( bytea * ) * (maxoff+1) );

    /* Sort entries */

    for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
    {
      GBT_VARKEY_R ro;
      tst = (char *) DatumGetPointer((entryvec->vector[i].key));
      cur = (char *) DatumGetPointer(PG_DETOAST_DATUM((entryvec->vector[i].key)));
      if ( tst != cur ){
        pfr[pfrcntr] = cur ;
        pfrcntr++;
      }
      ro = gbt_var_key_readable( ( GBT_VARKEY *) cur );
      if ( ro.lower == ro.upper ) /* leaf */
      {
        sv[svcntr] = gbt_var_leaf2node ( ( GBT_VARKEY *) cur , tinfo );
        arr[i].t   = sv[svcntr];
        if ( sv[svcntr] != ( GBT_VARKEY *) cur )
          svcntr++;
      } else {
        arr[i].t = ( GBT_VARKEY *) cur;
      }
      arr[i].i = i;
    }

    /* sort */
	gbt_vsrt_cmp_tinfo = tinfo;
    qsort((void*) &arr[FirstOffsetNumber],
		  maxoff-FirstOffsetNumber+1,
		  sizeof(Vsrt),
		  gbt_vsrt_cmp);

    /* We do simply create two parts */

    for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
    {
      if (i <= (maxoff - FirstOffsetNumber + 1) / 2)
      {
        gbt_var_bin_union(&v->spl_ldatum, arr[i].t, tinfo);
        v->spl_left[v->spl_nleft]   = arr[i].i;
        v->spl_nleft++;
      }
      else
      {
        gbt_var_bin_union(&v->spl_rdatum, arr[i].t, tinfo);
        v->spl_right[v->spl_nright]   = arr[i].i;
        v->spl_nright++;
      }
    }  

    /* Free detoasted keys */
    for ( i=0 ; i<pfrcntr; i++ ){
      pfree( pfr[i] );
    }

    /* Free strxfrm'ed leafs */
    for ( i=0 ; i<svcntr; i++ ){
      pfree( sv[i] );
    }

    if ( pfr )
    {
      pfree (pfr);
    }

    if ( sv )
    {
      pfree (sv);
    }

    /* Truncate (=compress) key */

    if ( tinfo->trnc )
    {

      int32        ll = gbt_var_node_cp_len ( (GBT_VARKEY *) DatumGetPointer(v->spl_ldatum) , tinfo );
      int32        lr = gbt_var_node_cp_len ( (GBT_VARKEY *) DatumGetPointer(v->spl_rdatum) , tinfo );
      GBT_VARKEY * dl ;
      GBT_VARKEY * dr ;

      ll = Max (ll,lr);
      ll++;

      dl = gbt_var_node_truncate ( (GBT_VARKEY *) DatumGetPointer(v->spl_ldatum) , ll, tinfo ) ;
      dr = gbt_var_node_truncate ( (GBT_VARKEY *) DatumGetPointer(v->spl_rdatum) , ll, tinfo ) ;
      pfree( DatumGetPointer(v->spl_ldatum) );
      pfree( DatumGetPointer(v->spl_rdatum) );
      v->spl_ldatum = PointerGetDatum ( dl );
      v->spl_rdatum = PointerGetDatum ( dr );

    }

	pfree(arr);

    return v;
}


/*
 * The GiST consistent method
 */
extern bool  
gbt_var_consistent( 
  GBT_VARKEY_R * key,
  const void * query,
  const StrategyNumber * strategy,
  bool is_leaf,
  const gbtree_vinfo * tinfo
)
{
        bool    retval = FALSE;

        switch (*strategy)
        {
                case BTLessEqualStrategyNumber:
                        if ( is_leaf )
                                retval = (*tinfo->f_ge)(query, (void*) key->lower);
                        else
                                retval = (*tinfo->f_cmp)((bytea*) query, key->lower) >= 0
                                           || gbt_var_node_pf_match( key ,query, tinfo );
                        break;
                case BTLessStrategyNumber:
                        if ( is_leaf )
                                retval = (*tinfo->f_gt)(query, (void*) key->lower);
                        else
                                retval = (*tinfo->f_cmp)((bytea*)query, key->lower) >= 0
                                           || gbt_var_node_pf_match( key, query , tinfo );
                        break;
                case BTEqualStrategyNumber:
                        if ( is_leaf )
                                retval = (*tinfo->f_eq)(query, (void*) key->lower);
                        else
                                retval = ( 
                                           (
                                             (*tinfo->f_cmp) (key->lower,(bytea*) query)<=0 &&
                                             (*tinfo->f_cmp) ((bytea*)query, (void*) key->upper)<=0 
                                           ) || gbt_var_node_pf_match( key, query, tinfo ) 
                                         );
                        break;
                case BTGreaterStrategyNumber:
                        if ( is_leaf )
                                retval = (*tinfo->f_lt)(query, (void*) key->upper);
                        else
                                retval = (*tinfo->f_cmp)((bytea*)query, key->upper)<=0 
                                           || gbt_var_node_pf_match( key, query, tinfo );
                        break;
                case BTGreaterEqualStrategyNumber:
                        if ( is_leaf )
                                retval = (*tinfo->f_le)(query, (void*) key->upper);
                        else
                                retval = (*tinfo->f_cmp)((bytea*) query, key->upper)<=0 
                                           || gbt_var_node_pf_match( key, query, tinfo );
                        break;
                default:
                        retval = FALSE;
        }

        return (retval);
}
