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

#include <limits.h>

#include "btree_gist.h"
#include "btree_utils_num.h"
#include "utils/fmgrprotos.h"
#include "utils/timestamp.h"
#include "utils/float.h"
#include "utils/sortsupport.h"

typedef struct
{
 Timestamp lower;
 Timestamp upper;
} tsKEY;

/* GiST support functions */
PG_FUNCTION_INFO_V1(gbt_ts_compress);
PG_FUNCTION_INFO_V1(gbt_tstz_compress);
PG_FUNCTION_INFO_V1(gbt_ts_fetch);
PG_FUNCTION_INFO_V1(gbt_ts_union);
PG_FUNCTION_INFO_V1(gbt_ts_picksplit);
PG_FUNCTION_INFO_V1(gbt_ts_consistent);
PG_FUNCTION_INFO_V1(gbt_ts_distance);
PG_FUNCTION_INFO_V1(gbt_tstz_consistent);
PG_FUNCTION_INFO_V1(gbt_tstz_distance);
PG_FUNCTION_INFO_V1(gbt_ts_penalty);
PG_FUNCTION_INFO_V1(gbt_ts_same);
PG_FUNCTION_INFO_V1(gbt_ts_sortsupport);


#ifdef USE_FLOAT8_BYVAL
#define TimestampGetDatumFast(X) TimestampGetDatum(X)
#else
#define TimestampGetDatumFast(X) PointerGetDatum(&(X))
#endif


/* define for comparison */

static bool
gbt_tsgt(const void *a, const void *b, FmgrInfo *flinfo)
{
 const Timestamp *aa = (const Timestamp *) a;
 const Timestamp *bb = (const Timestamp *) b;

 return DatumGetBool(DirectFunctionCall2(timestamp_gt,
           TimestampGetDatumFast(*aa),
           TimestampGetDatumFast(*bb)));
}

static bool
gbt_tsge(const void *a, const void *b, FmgrInfo *flinfo)
{
 const Timestamp *aa = (const Timestamp *) a;
 const Timestamp *bb = (const Timestamp *) b;

 return DatumGetBool(DirectFunctionCall2(timestamp_ge,
           TimestampGetDatumFast(*aa),
           TimestampGetDatumFast(*bb)));
}

static bool
gbt_tseq(const void *a, const void *b, FmgrInfo *flinfo)
{
 const Timestamp *aa = (const Timestamp *) a;
 const Timestamp *bb = (const Timestamp *) b;

 return DatumGetBool(DirectFunctionCall2(timestamp_eq,
           TimestampGetDatumFast(*aa),
           TimestampGetDatumFast(*bb)));
}

static bool
gbt_tsle(const void *a, const void *b, FmgrInfo *flinfo)
{
 const Timestamp *aa = (const Timestamp *) a;
 const Timestamp *bb = (const Timestamp *) b;

 return DatumGetBool(DirectFunctionCall2(timestamp_le,
           TimestampGetDatumFast(*aa),
           TimestampGetDatumFast(*bb)));
}

static bool
gbt_tslt(const void *a, const void *b, FmgrInfo *flinfo)
{
 const Timestamp *aa = (const Timestamp *) a;
 const Timestamp *bb = (const Timestamp *) b;

 return DatumGetBool(DirectFunctionCall2(timestamp_lt,
           TimestampGetDatumFast(*aa),
           TimestampGetDatumFast(*bb)));
}

static int
gbt_tskey_cmp(const void *a, const void *b, FmgrInfo *flinfo)
{
 tsKEY    *ia = (tsKEY *) (((const Nsrt *) a)->t);
 tsKEY    *ib = (tsKEY *) (((const Nsrt *) b)->t);
 int   res;

 res = DatumGetInt32(DirectFunctionCall2(timestamp_cmp, TimestampGetDatumFast(ia->lower), TimestampGetDatumFast(ib->lower)));
 if (res == 0)
  return DatumGetInt32(DirectFunctionCall2(timestamp_cmp, TimestampGetDatumFast(ia->upper), TimestampGetDatumFast(ib->upper)));

 return res;
}

static float8
gbt_ts_dist(const void *a, const void *b, FmgrInfo *flinfo)
{
 const Timestamp *aa = (const Timestamp *) a;
 const Timestamp *bb = (const Timestamp *) b;
 Interval   *i;

 if (TIMESTAMP_NOT_FINITE(*aa) || TIMESTAMP_NOT_FINITE(*bb))
  return get_float8_infinity();

 i = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
             TimestampGetDatumFast(*aa),
             TimestampGetDatumFast(*bb)));
 return fabs(INTERVAL_TO_SEC(i));
}

static const gbtree_ninfo tinfo =
{
 gbt_t_ts,
 sizeof(Timestamp),
 16,       /* sizeof(gbtreekey16) */
 gbt_tsgt,
 gbt_tsge,
 gbt_tseq,
 gbt_tsle,
 gbt_tslt,
 gbt_tskey_cmp,
 gbt_ts_dist
};


PG_FUNCTION_INFO_V1(ts_dist);
Datum
ts_dist(PG_FUNCTION_ARGS)
{
 Timestamp a = PG_GETARG_TIMESTAMP(0);
 Timestamp b = PG_GETARG_TIMESTAMP(1);
 Interval   *r;

 if (TIMESTAMP_NOT_FINITE(a) || TIMESTAMP_NOT_FINITE(b))
 {
  Interval   *p = palloc(sizeof(Interval));

  p->day = INT_MAX;
  p->month = INT_MAX;
  p->time = PG_INT64_MAX;
  PG_RETURN_INTERVAL_P(p);
 }
 else
  r = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
              PG_GETARG_DATUM(0),
              PG_GETARG_DATUM(1)));
 PG_RETURN_INTERVAL_P(abs_interval(r));
}

PG_FUNCTION_INFO_V1(tstz_dist);
Datum
tstz_dist(PG_FUNCTION_ARGS)
{
 TimestampTz a = PG_GETARG_TIMESTAMPTZ(0);
 TimestampTz b = PG_GETARG_TIMESTAMPTZ(1);
 Interval   *r;

 if (TIMESTAMP_NOT_FINITE(a) || TIMESTAMP_NOT_FINITE(b))
 {
  Interval   *p = palloc(sizeof(Interval));

  p->day = INT_MAX;
  p->month = INT_MAX;
  p->time = PG_INT64_MAX;
  PG_RETURN_INTERVAL_P(p);
 }

 r = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
             PG_GETARG_DATUM(0),
             PG_GETARG_DATUM(1)));
 PG_RETURN_INTERVAL_P(abs_interval(r));
}

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

static inline Timestamp
tstz_to_ts_gmt(TimestampTz ts)
{
 /* No timezone correction is needed, since GMT is offset 0 by definition */
 return (Timestamp) ts;
}


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

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

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

 if (entry->leafkey)
 {
  tsKEY    *r = (tsKEY *) palloc(sizeof(tsKEY));
  TimestampTz ts = DatumGetTimestampTz(entry->key);
  Timestamp gmt;

  gmt = tstz_to_ts_gmt(ts);

  retval = palloc(sizeof(GISTENTRY));
  r->lower = r->upper = gmt;
  gistentryinit(*retval, PointerGetDatum(r),
       entry->rel, entry->page,
       entry->offset, false);
 }
 else
  retval = entry;

 PG_RETURN_POINTER(retval);
}

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

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

Datum
gbt_ts_consistent(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 Timestamp query = PG_GETARG_TIMESTAMP(1);
 StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

 /* Oid subtype = PG_GETARG_OID(3); */
 bool    *recheck = (bool *) PG_GETARG_POINTER(4);
 tsKEY    *kkk = (tsKEY *) DatumGetPointer(entry->key);
 GBT_NUMKEY_R key;

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

 key.lower = (GBT_NUMKEY *) &kkk->lower;
 key.upper = (GBT_NUMKEY *) &kkk->upper;

 PG_RETURN_BOOL(gbt_num_consistent(&key, &query, &strategy,
           GIST_LEAF(entry), &tinfo, fcinfo->flinfo));
}

Datum
gbt_ts_distance(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 Timestamp query = PG_GETARG_TIMESTAMP(1);

 /* Oid subtype = PG_GETARG_OID(3); */
 tsKEY    *kkk = (tsKEY *) DatumGetPointer(entry->key);
 GBT_NUMKEY_R key;

 key.lower = (GBT_NUMKEY *) &kkk->lower;
 key.upper = (GBT_NUMKEY *) &kkk->upper;

 PG_RETURN_FLOAT8(gbt_num_distance(&key, &query, GIST_LEAF(entry),
           &tinfo, fcinfo->flinfo));
}

Datum
gbt_tstz_consistent(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 TimestampTz query = PG_GETARG_TIMESTAMPTZ(1);
 StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

 /* Oid subtype = PG_GETARG_OID(3); */
 bool    *recheck = (bool *) PG_GETARG_POINTER(4);
 char    *kkk = (char *) DatumGetPointer(entry->key);
 GBT_NUMKEY_R key;
 Timestamp qqq;

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

 key.lower = (GBT_NUMKEY *) &kkk[0];
 key.upper = (GBT_NUMKEY *) &kkk[MAXALIGN(tinfo.size)];
 qqq = tstz_to_ts_gmt(query);

 PG_RETURN_BOOL(gbt_num_consistent(&key, &qqq, &strategy,
           GIST_LEAF(entry), &tinfo, fcinfo->flinfo));
}

Datum
gbt_tstz_distance(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 TimestampTz query = PG_GETARG_TIMESTAMPTZ(1);

 /* Oid subtype = PG_GETARG_OID(3); */
 char    *kkk = (char *) DatumGetPointer(entry->key);
 GBT_NUMKEY_R key;
 Timestamp qqq;

 key.lower = (GBT_NUMKEY *) &kkk[0];
 key.upper = (GBT_NUMKEY *) &kkk[MAXALIGN(tinfo.size)];
 qqq = tstz_to_ts_gmt(query);

 PG_RETURN_FLOAT8(gbt_num_distance(&key, &qqq, GIST_LEAF(entry),
           &tinfo, fcinfo->flinfo));
}


Datum
gbt_ts_union(PG_FUNCTION_ARGS)
{
 GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 void    *out = palloc(sizeof(tsKEY));

 *(int *) PG_GETARG_POINTER(1) = sizeof(tsKEY);
 PG_RETURN_POINTER(gbt_num_union(out, entryvec, &tinfo, fcinfo->flinfo));
}


#define penalty_check_max_float(val) \
 do { \
  if ( val > FLT_MAX ) \
    val = FLT_MAX; \
  if ( val < -FLT_MAX ) \
    val = -FLT_MAX; \
 } while (0)


Datum
gbt_ts_penalty(PG_FUNCTION_ARGS)
{
 tsKEY    *origentry = (tsKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
 tsKEY    *newentry = (tsKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(1))->key);
 float    *result = (float *) PG_GETARG_POINTER(2);

 double  orgdbl[2],
    newdbl[2];

 /*
  * We are always using "double" timestamps here. Precision should be good
  * enough.
 */
 orgdbl[0] = ((double) origentry->lower);
 orgdbl[1] = ((double) origentry->upper);
 newdbl[0] = ((double) newentry->lower);
 newdbl[1] = ((double) newentry->upper);

 penalty_check_max_float(orgdbl[0]);
 penalty_check_max_float(orgdbl[1]);
 penalty_check_max_float(newdbl[0]);
 penalty_check_max_float(newdbl[1]);

 penalty_num(result, orgdbl[0], orgdbl[1], newdbl[0], newdbl[1]);

 PG_RETURN_POINTER(result);
}


Datum
gbt_ts_picksplit(PG_FUNCTION_ARGS)
{
 PG_RETURN_POINTER(gbt_num_picksplit((GistEntryVector *) PG_GETARG_POINTER(0),
          (GIST_SPLITVEC *) PG_GETARG_POINTER(1),
          &tinfo, fcinfo->flinfo));
}

Datum
gbt_ts_same(PG_FUNCTION_ARGS)
{
 tsKEY    *b1 = (tsKEY *) PG_GETARG_POINTER(0);
 tsKEY    *b2 = (tsKEY *) PG_GETARG_POINTER(1);
 bool    *result = (bool *) PG_GETARG_POINTER(2);

 *result = gbt_num_same((void *) b1, (void *) b2, &tinfo, fcinfo->flinfo);
 PG_RETURN_POINTER(result);
}

static int
gbt_ts_ssup_cmp(Datum x, Datum y, SortSupport ssup)
{
 tsKEY    *arg1 = (tsKEY *) DatumGetPointer(x);
 tsKEY    *arg2 = (tsKEY *) DatumGetPointer(y);

 /* for leaf items we expect lower == upper, so only compare lower */
 return DatumGetInt32(DirectFunctionCall2(timestamp_cmp,
            TimestampGetDatumFast(arg1->lower),
            TimestampGetDatumFast(arg2->lower)));
}

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

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

 PG_RETURN_VOID();
}