/*
 * contrib/btree_gist/btree_numeric.c
 */
#include "postgres.h"

#include <math.h>
#include <float.h>

#include "btree_gist.h"
#include "btree_utils_var.h"
#include "utils/builtins.h"
#include "utils/numeric.h"
#include "utils/rel.h"
#include "utils/sortsupport.h"

/* GiST support functions */
PG_FUNCTION_INFO_V1(gbt_numeric_compress);
PG_FUNCTION_INFO_V1(gbt_numeric_union);
PG_FUNCTION_INFO_V1(gbt_numeric_picksplit);
PG_FUNCTION_INFO_V1(gbt_numeric_consistent);
PG_FUNCTION_INFO_V1(gbt_numeric_penalty);
PG_FUNCTION_INFO_V1(gbt_numeric_same);
PG_FUNCTION_INFO_V1(gbt_numeric_sortsupport);


/* define for comparison */

static bool
gbt_numeric_gt(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(numeric_gt,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_numeric_ge(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(numeric_ge,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_numeric_eq(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(numeric_eq,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_numeric_le(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(numeric_le,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_numeric_lt(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(numeric_lt,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static int32
gbt_numeric_cmp(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetInt32(DirectFunctionCall2(numeric_cmp,
            PointerGetDatum(a),
            PointerGetDatum(b)));
}


static const gbtree_vinfo tinfo =
{
 gbt_t_numeric,
 0,
 false,
 gbt_numeric_gt,
 gbt_numeric_ge,
 gbt_numeric_eq,
 gbt_numeric_le,
 gbt_numeric_lt,
 gbt_numeric_cmp,
 NULL
};


/**************************************************
 * GiST support functions
 **************************************************/

Datum
gbt_numeric_compress(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

 PG_RETURN_POINTER(gbt_var_compress(entry, &tinfo));
}

Datum
gbt_numeric_consistent(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 void    *query = DatumGetNumeric(PG_GETARG_DATUM(1));
 StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

 /* Oid subtype = PG_GETARG_OID(3); */
 bool    *recheck = (bool *) PG_GETARG_POINTER(4);
 bool  retval;
 GBT_VARKEY *key = (GBT_VARKEY *) DatumGetPointer(entry->key);
 GBT_VARKEY_R r = gbt_var_key_readable(key);

 /* All cases served by this function are exact */
 *recheck = false;

 retval = gbt_var_consistent(&r, query, strategy, PG_GET_COLLATION(),
        GIST_LEAF(entry), &tinfo, fcinfo->flinfo);
 PG_RETURN_BOOL(retval);
}

Datum
gbt_numeric_union(PG_FUNCTION_ARGS)
{
 GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 int32    *size = (int *) PG_GETARG_POINTER(1);

 PG_RETURN_POINTER(gbt_var_union(entryvec, size, PG_GET_COLLATION(),
         &tinfo, fcinfo->flinfo));
}

Datum
gbt_numeric_same(PG_FUNCTION_ARGS)
{
 Datum  d1 = PG_GETARG_DATUM(0);
 Datum  d2 = PG_GETARG_DATUM(1);
 bool    *result = (bool *) PG_GETARG_POINTER(2);

 *result = gbt_var_same(d1, d2, PG_GET_COLLATION(), &tinfo, fcinfo->flinfo);
 PG_RETURN_POINTER(result);
}

Datum
gbt_numeric_penalty(PG_FUNCTION_ARGS)
{
 GISTENTRY  *o = (GISTENTRY *) PG_GETARG_POINTER(0);
 GISTENTRY  *n = (GISTENTRY *) PG_GETARG_POINTER(1);
 float    *result = (float *) PG_GETARG_POINTER(2);

 Numeric  us,
    os,
    ds;

 GBT_VARKEY *org = (GBT_VARKEY *) DatumGetPointer(o->key);
 GBT_VARKEY *newe = (GBT_VARKEY *) DatumGetPointer(n->key);
 Datum  uni;
 GBT_VARKEY_R rk,
    ok,
    uk;

 rk = gbt_var_key_readable(org);
 uni = PointerGetDatum(gbt_var_key_copy(&rk));
 gbt_var_bin_union(&uni, newe, PG_GET_COLLATION(), &tinfo, fcinfo->flinfo);
 ok = gbt_var_key_readable(org);
 uk = gbt_var_key_readable((GBT_VARKEY *) DatumGetPointer(uni));

 us = DatumGetNumeric(DirectFunctionCall2(numeric_sub,
            PointerGetDatum(uk.upper),
            PointerGetDatum(uk.lower)));

 os = DatumGetNumeric(DirectFunctionCall2(numeric_sub,
            PointerGetDatum(ok.upper),
            PointerGetDatum(ok.lower)));

 ds = DatumGetNumeric(DirectFunctionCall2(numeric_sub,
            NumericGetDatum(us),
            NumericGetDatum(os)));

 if (numeric_is_nan(us))
 {
  if (numeric_is_nan(os))
   *result = 0.0;
  else
   *result = 1.0;
 }
 else
 {
  Numeric  nul = int64_to_numeric(0);

  *result = 0.0;

  if (DirectFunctionCall2(numeric_gt, NumericGetDatum(ds), NumericGetDatum(nul)))
  {
   *result += FLT_MIN;
   os = DatumGetNumeric(DirectFunctionCall2(numeric_div,
              NumericGetDatum(ds),
              NumericGetDatum(us)));
   *result += (float4) DatumGetFloat8(DirectFunctionCall1(numeric_float8_no_overflow, NumericGetDatum(os)));
  }
 }

 if (*result > 0)
  *result *= (FLT_MAX / (((GISTENTRY *) PG_GETARG_POINTER(0))->rel->rd_att->natts + 1));

 PG_RETURN_POINTER(result);
}

Datum
gbt_numeric_picksplit(PG_FUNCTION_ARGS)
{
 GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);

 gbt_var_picksplit(entryvec, v, PG_GET_COLLATION(),
       &tinfo, fcinfo->flinfo);
 PG_RETURN_POINTER(v);
}

static int
gbt_numeric_ssup_cmp(Datum x, Datum y, SortSupport ssup)
{
 GBT_VARKEY *key1 = PG_DETOAST_DATUM(x);
 GBT_VARKEY *key2 = PG_DETOAST_DATUM(y);

 GBT_VARKEY_R arg1 = gbt_var_key_readable(key1);
 GBT_VARKEY_R arg2 = gbt_var_key_readable(key2);
 Datum  result;

 /* for leaf items we expect lower == upper, so only compare lower */
 result = DirectFunctionCall2(numeric_cmp,
         PointerGetDatum(arg1.lower),
         PointerGetDatum(arg2.lower));

 GBT_FREE_IF_COPY(key1, x);
 GBT_FREE_IF_COPY(key2, y);

 return DatumGetInt32(result);
}

Datum
gbt_numeric_sortsupport(PG_FUNCTION_ARGS)
{
 SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);

 ssup->comparator = gbt_numeric_ssup_cmp;
 ssup->ssup_extra = NULL;

 PG_RETURN_VOID();
}