/* 
 * interface functions to dictionary 
 * Teodor Sigaev <teodor@sigaev.ru>
 */
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "postgres.h"
#include "fmgr.h"
#include "utils/array.h"
#include "catalog/pg_type.h"
#include "executor/spi.h"

#include "dict.h"
#include "common.h"
#include "snmap.h"

/*********top interface**********/

static void *plan_getdict=NULL;

void
init_dict(Oid id, DictInfo *dict) {
	Oid arg[1]={ OIDOID };
	bool isnull;
	Datum pars[1]={ ObjectIdGetDatum(id) };
	int stat;

	memset(dict,0,sizeof(DictInfo));
	SPI_connect();
	if ( !plan_getdict ) {
		plan_getdict = SPI_saveplan( SPI_prepare( "select dict_init, dict_initoption, dict_lexize from pg_ts_dict where oid = $1" , 1, arg ) );
		if ( !plan_getdict ) 
			ts_error(ERROR, "SPI_prepare() failed");
	}

	stat = SPI_execp(plan_getdict, pars, " ", 1);
	if ( stat < 0 )
		ts_error (ERROR, "SPI_execp return %d", stat);
	if ( SPI_processed > 0 ) {
		Datum opt;
		Oid	oid=InvalidOid;
		oid=DatumGetObjectId( SPI_getbinval(SPI_tuptable->vals[0], SPI_tuptable->tupdesc, 1, &isnull) );
		if ( !(isnull || oid==InvalidOid) ) {
			opt=SPI_getbinval(SPI_tuptable->vals[0], SPI_tuptable->tupdesc, 2, &isnull);
			dict->dictionary=(void*)DatumGetPointer(OidFunctionCall1(oid, opt)); 
		}
		oid=DatumGetObjectId( SPI_getbinval(SPI_tuptable->vals[0], SPI_tuptable->tupdesc, 3, &isnull) );
		if ( isnull || oid==InvalidOid ) 
			ts_error(ERROR, "Null dict_lexize for dictonary %d", id);
		fmgr_info_cxt(oid, &(dict->lexize_info), TopMemoryContext);
		dict->dict_id=id;
	} else 
		ts_error(ERROR, "No dictionary with id %d", id);
	SPI_finish();
}

typedef struct {
	DictInfo	*last_dict;
	int		len;
	int		reallen;
	DictInfo	*list;
	SNMap		name2id_map;
} DictList;

static DictList DList = {NULL,0,0,NULL,{0,0,NULL}};

void
reset_dict(void) {
	freeSNMap( &(DList.name2id_map) );
	/* XXX need to free DList.list[*].dictionary */
	if ( DList.list )
		free(DList.list);
	memset(&DList,0,sizeof(DictList));
}


static int
comparedict(const void *a, const void *b) {
	return ((DictInfo*)a)->dict_id - ((DictInfo*)b)->dict_id;
}

DictInfo *
finddict(Oid id) {
	/* last used dict */
	if ( DList.last_dict && DList.last_dict->dict_id==id )
		return DList.last_dict;


	/* already used dict */
	if (  DList.len != 0 ) {
		DictInfo key;
		key.dict_id=id;
		DList.last_dict = bsearch(&key, DList.list, DList.len, sizeof(DictInfo), comparedict);
		if ( DList.last_dict != NULL )
			return DList.last_dict;
	}

	/* last chance */
	if ( DList.len==DList.reallen ) {
		DictInfo *tmp;
		int reallen = ( DList.reallen ) ? 2*DList.reallen : 16;
		tmp=(DictInfo*)realloc(DList.list,sizeof(DictInfo)*reallen);
		if ( !tmp ) 
			ts_error(ERROR,"No memory");
		DList.reallen=reallen;
		DList.list=tmp;
	}
	DList.last_dict=&(DList.list[DList.len]);
	init_dict(id, DList.last_dict);

	DList.len++;
	qsort(DList.list, DList.len, sizeof(DictInfo), comparedict);
	return finddict(id); /* qsort changed order!! */;
}

static void *plan_name2id=NULL;

Oid
name2id_dict(text *name) {
	Oid arg[1]={ TEXTOID };
	bool isnull;
	Datum pars[1]={ PointerGetDatum(name) };
	int stat;
	Oid id=findSNMap_t( &(DList.name2id_map), name );

	if ( id ) 
		return id;
	
	SPI_connect();
	if ( !plan_name2id ) {
		plan_name2id = SPI_saveplan( SPI_prepare( "select oid from pg_ts_dict where dict_name = $1" , 1, arg ) );
		if ( !plan_name2id ) 
			ts_error(ERROR, "SPI_prepare() failed");
	}

	stat = SPI_execp(plan_name2id, pars, " ", 1);
	if ( stat < 0 )
		ts_error (ERROR, "SPI_execp return %d", stat);
	if ( SPI_processed > 0 )
		id=DatumGetObjectId( SPI_getbinval(SPI_tuptable->vals[0], SPI_tuptable->tupdesc, 1, &isnull) );
	else  
		ts_error(ERROR, "No dictionary with name '%s'", text2char(name));
	SPI_finish();
	addSNMap_t( &(DList.name2id_map), name, id );
	return id;
}


/******sql-level interface******/
PG_FUNCTION_INFO_V1(lexize);
Datum lexize(PG_FUNCTION_ARGS);

Datum
lexize(PG_FUNCTION_ARGS) {
	text *in=PG_GETARG_TEXT_P(1);
	DictInfo *dict = finddict( PG_GETARG_OID(0) );
	char	**res, **ptr;
	Datum   *da;
	ArrayType    *a;


	ptr = res = (char**)DatumGetPointer(
		FunctionCall3(&(dict->lexize_info), 
			PointerGetDatum(dict->dictionary),
			PointerGetDatum(VARDATA(in)),
			Int32GetDatum(VARSIZE(in)-VARHDRSZ)
		)
	);
	PG_FREE_IF_COPY(in, 1);
	if ( !res ) {
		if (PG_NARGS() > 2)  
			PG_RETURN_POINTER(NULL);
		else
			PG_RETURN_NULL();
	}

	while(*ptr) ptr++;
	da = (Datum*)palloc(sizeof(Datum)*(ptr-res+1));
	ptr=res;
	while(*ptr) {
		da[ ptr-res ] = PointerGetDatum( char2text(*ptr) );
		ptr++;
	}

	a = construct_array(
		da,
		ptr-res,
		TEXTOID,
		-1,
		false,
		'i'
	);

	ptr=res; 
	while(*ptr) {
		pfree( DatumGetPointer(da[ ptr-res ]) );
		pfree( *ptr );
		ptr++;
	}
	pfree(res);
	pfree(da);
		
	PG_RETURN_POINTER(a);	
}

PG_FUNCTION_INFO_V1(lexize_byname);
Datum lexize_byname(PG_FUNCTION_ARGS);
Datum 
lexize_byname(PG_FUNCTION_ARGS) {
	text *dictname=PG_GETARG_TEXT_P(0);
	Datum res;

	strdup("simple");
	res=DirectFunctionCall3(
		lexize,
		ObjectIdGetDatum(name2id_dict(dictname)),
		PG_GETARG_DATUM(1),
		(Datum)0
	);
	PG_FREE_IF_COPY(dictname, 0);
	if (res) 
		PG_RETURN_DATUM(res); 
	else 
		PG_RETURN_NULL();
}

static Oid currect_dictionary_id=0;

PG_FUNCTION_INFO_V1(set_curdict);
Datum set_curdict(PG_FUNCTION_ARGS);
Datum
set_curdict(PG_FUNCTION_ARGS) {
	finddict(PG_GETARG_OID(0));
	currect_dictionary_id=PG_GETARG_OID(0);
	PG_RETURN_VOID();
}

PG_FUNCTION_INFO_V1(set_curdict_byname);
Datum set_curdict_byname(PG_FUNCTION_ARGS);
Datum
set_curdict_byname(PG_FUNCTION_ARGS) {
	text *dictname=PG_GETARG_TEXT_P(0);

	DirectFunctionCall1(
		set_curdict,
		ObjectIdGetDatum( name2id_dict(dictname) )
	);
	PG_FREE_IF_COPY(dictname, 0);
	PG_RETURN_VOID();
}

PG_FUNCTION_INFO_V1(lexize_bycurrent);
Datum lexize_bycurrent(PG_FUNCTION_ARGS);
Datum 
lexize_bycurrent(PG_FUNCTION_ARGS) {
	Datum res;
	if ( currect_dictionary_id == 0 )
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("no currect dictionary"),
				 errhint("Execute select set_curdict().")));

	res = DirectFunctionCall3(
		lexize,
		ObjectIdGetDatum(currect_dictionary_id),
		PG_GETARG_DATUM(0),
		(Datum)0
	);
	if (res) 
		PG_RETURN_DATUM(res);
	else 
		PG_RETURN_NULL();
}