/*-------------------------------------------------------------------------
 *
 * wparser.c
 *		Standard interface to word parser
 *
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/tsearch/wparser.c,v 1.8 2008/01/15 18:22:47 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "funcapi.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/skey.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_ts_parser.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "tsearch/ts_cache.h"
#include "tsearch/ts_public.h"
#include "tsearch/ts_utils.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/rel.h"
#include "utils/syscache.h"


/******sql-level interface******/

typedef struct
{
	int			cur;
	LexDescr   *list;
} TSTokenTypeStorage;

static void
tt_setup_firstcall(FuncCallContext *funcctx, Oid prsid)
{
	TupleDesc	tupdesc;
	MemoryContext oldcontext;
	TSTokenTypeStorage *st;
	TSParserCacheEntry *prs = lookup_ts_parser_cache(prsid);

	if (!OidIsValid(prs->lextypeOid))
		elog(ERROR, "method lextype isn't defined for text search parser %u",
			 prsid);

	oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

	st = (TSTokenTypeStorage *) palloc(sizeof(TSTokenTypeStorage));
	st->cur = 0;
	/* OidFunctionCall0 is absent */
	st->list = (LexDescr *) DatumGetPointer(OidFunctionCall1(prs->lextypeOid,
															 (Datum) 0));
	funcctx->user_fctx = (void *) st;

	tupdesc = CreateTemplateTupleDesc(3, false);
	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "tokid",
					   INT4OID, -1, 0);
	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "alias",
					   TEXTOID, -1, 0);
	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "description",
					   TEXTOID, -1, 0);

	funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
	MemoryContextSwitchTo(oldcontext);
}

static Datum
tt_process_call(FuncCallContext *funcctx)
{
	TSTokenTypeStorage *st;

	st = (TSTokenTypeStorage *) funcctx->user_fctx;
	if (st->list && st->list[st->cur].lexid)
	{
		Datum		result;
		char	   *values[3];
		char		txtid[16];
		HeapTuple	tuple;

		sprintf(txtid, "%d", st->list[st->cur].lexid);
		values[0] = txtid;
		values[1] = st->list[st->cur].alias;
		values[2] = st->list[st->cur].descr;

		tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
		result = HeapTupleGetDatum(tuple);

		pfree(values[1]);
		pfree(values[2]);
		st->cur++;
		return result;
	}
	if (st->list)
		pfree(st->list);
	pfree(st);
	return (Datum) 0;
}

Datum
ts_token_type_byid(PG_FUNCTION_ARGS)
{
	FuncCallContext *funcctx;
	Datum		result;

	if (SRF_IS_FIRSTCALL())
	{
		funcctx = SRF_FIRSTCALL_INIT();
		tt_setup_firstcall(funcctx, PG_GETARG_OID(0));
	}

	funcctx = SRF_PERCALL_SETUP();

	if ((result = tt_process_call(funcctx)) != (Datum) 0)
		SRF_RETURN_NEXT(funcctx, result);
	SRF_RETURN_DONE(funcctx);
}

Datum
ts_token_type_byname(PG_FUNCTION_ARGS)
{
	FuncCallContext *funcctx;
	Datum		result;

	if (SRF_IS_FIRSTCALL())
	{
		text	   *prsname = PG_GETARG_TEXT_P(0);
		Oid			prsId;

		funcctx = SRF_FIRSTCALL_INIT();
		prsId = TSParserGetPrsid(textToQualifiedNameList(prsname), false);
		tt_setup_firstcall(funcctx, prsId);
	}

	funcctx = SRF_PERCALL_SETUP();

	if ((result = tt_process_call(funcctx)) != (Datum) 0)
		SRF_RETURN_NEXT(funcctx, result);
	SRF_RETURN_DONE(funcctx);
}

typedef struct
{
	int			type;
	char	   *lexeme;
} LexemeEntry;

typedef struct
{
	int			cur;
	int			len;
	LexemeEntry *list;
} PrsStorage;


static void
prs_setup_firstcall(FuncCallContext *funcctx, Oid prsid, text *txt)
{
	TupleDesc	tupdesc;
	MemoryContext oldcontext;
	PrsStorage *st;
	TSParserCacheEntry *prs = lookup_ts_parser_cache(prsid);
	char	   *lex = NULL;
	int			llen = 0,
				type = 0;
	void	   *prsdata;

	oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

	st = (PrsStorage *) palloc(sizeof(PrsStorage));
	st->cur = 0;
	st->len = 16;
	st->list = (LexemeEntry *) palloc(sizeof(LexemeEntry) * st->len);

	prsdata = (void *) DatumGetPointer(FunctionCall2(&prs->prsstart,
											   PointerGetDatum(VARDATA(txt)),
									Int32GetDatum(VARSIZE(txt) - VARHDRSZ)));

	while ((type = DatumGetInt32(FunctionCall3(&prs->prstoken,
											   PointerGetDatum(prsdata),
											   PointerGetDatum(&lex),
											   PointerGetDatum(&llen)))) != 0)
	{
		if (st->cur >= st->len)
		{
			st->len = 2 * st->len;
			st->list = (LexemeEntry *) repalloc(st->list, sizeof(LexemeEntry) * st->len);
		}
		st->list[st->cur].lexeme = palloc(llen + 1);
		memcpy(st->list[st->cur].lexeme, lex, llen);
		st->list[st->cur].lexeme[llen] = '\0';
		st->list[st->cur].type = type;
		st->cur++;
	}

	FunctionCall1(&prs->prsend, PointerGetDatum(prsdata));

	st->len = st->cur;
	st->cur = 0;

	funcctx->user_fctx = (void *) st;
	tupdesc = CreateTemplateTupleDesc(2, false);
	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "tokid",
					   INT4OID, -1, 0);
	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "token",
					   TEXTOID, -1, 0);

	funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
	MemoryContextSwitchTo(oldcontext);
}

static Datum
prs_process_call(FuncCallContext *funcctx)
{
	PrsStorage *st;

	st = (PrsStorage *) funcctx->user_fctx;
	if (st->cur < st->len)
	{
		Datum		result;
		char	   *values[2];
		char		tid[16];
		HeapTuple	tuple;

		values[0] = tid;
		sprintf(tid, "%d", st->list[st->cur].type);
		values[1] = st->list[st->cur].lexeme;
		tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
		result = HeapTupleGetDatum(tuple);

		pfree(values[1]);
		st->cur++;
		return result;
	}
	else
	{
		if (st->list)
			pfree(st->list);
		pfree(st);
	}
	return (Datum) 0;
}

Datum
ts_parse_byid(PG_FUNCTION_ARGS)
{
	FuncCallContext *funcctx;
	Datum		result;

	if (SRF_IS_FIRSTCALL())
	{
		text	   *txt = PG_GETARG_TEXT_P(1);

		funcctx = SRF_FIRSTCALL_INIT();
		prs_setup_firstcall(funcctx, PG_GETARG_OID(0), txt);
		PG_FREE_IF_COPY(txt, 1);
	}

	funcctx = SRF_PERCALL_SETUP();

	if ((result = prs_process_call(funcctx)) != (Datum) 0)
		SRF_RETURN_NEXT(funcctx, result);
	SRF_RETURN_DONE(funcctx);
}

Datum
ts_parse_byname(PG_FUNCTION_ARGS)
{
	FuncCallContext *funcctx;
	Datum		result;

	if (SRF_IS_FIRSTCALL())
	{
		text	   *prsname = PG_GETARG_TEXT_P(0);
		text	   *txt = PG_GETARG_TEXT_P(1);
		Oid			prsId;

		funcctx = SRF_FIRSTCALL_INIT();
		prsId = TSParserGetPrsid(textToQualifiedNameList(prsname), false);
		prs_setup_firstcall(funcctx, prsId, txt);
	}

	funcctx = SRF_PERCALL_SETUP();

	if ((result = prs_process_call(funcctx)) != (Datum) 0)
		SRF_RETURN_NEXT(funcctx, result);
	SRF_RETURN_DONE(funcctx);
}

Datum
ts_headline_byid_opt(PG_FUNCTION_ARGS)
{
	text	   *in = PG_GETARG_TEXT_P(1);
	TSQuery		query = PG_GETARG_TSQUERY(2);
	text	   *opt = (PG_NARGS() > 3 && PG_GETARG_POINTER(3)) ? PG_GETARG_TEXT_P(3) : NULL;
	HeadlineParsedText prs;
	List	   *prsoptions;
	text	   *out;
	TSConfigCacheEntry *cfg;
	TSParserCacheEntry *prsobj;

	cfg = lookup_ts_config_cache(PG_GETARG_OID(0));
	prsobj = lookup_ts_parser_cache(cfg->prsId);

	if (!OidIsValid(prsobj->headlineOid))
		ereport(ERROR, 
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("text search parser does not support headline creation")));

	memset(&prs, 0, sizeof(HeadlineParsedText));
	prs.lenwords = 32;
	prs.words = (HeadlineWordEntry *) palloc(sizeof(HeadlineWordEntry) * prs.lenwords);

	hlparsetext(cfg->cfgId, &prs, query, VARDATA(in), VARSIZE(in) - VARHDRSZ);

	if (opt)
		prsoptions = deserialize_deflist(PointerGetDatum(opt));
	else
		prsoptions = NIL;

	FunctionCall3(&(prsobj->prsheadline),
				  PointerGetDatum(&prs),
				  PointerGetDatum(prsoptions),
				  PointerGetDatum(query));

	out = generateHeadline(&prs);

	PG_FREE_IF_COPY(in, 1);
	PG_FREE_IF_COPY(query, 2);
	if (opt)
		PG_FREE_IF_COPY(opt, 3);
	pfree(prs.words);
	pfree(prs.startsel);
	pfree(prs.stopsel);

	PG_RETURN_POINTER(out);
}

Datum
ts_headline_byid(PG_FUNCTION_ARGS)
{
	PG_RETURN_DATUM(DirectFunctionCall3(ts_headline_byid_opt,
										PG_GETARG_DATUM(0),
										PG_GETARG_DATUM(1),
										PG_GETARG_DATUM(2)));
}

Datum
ts_headline(PG_FUNCTION_ARGS)
{
	PG_RETURN_DATUM(DirectFunctionCall3(ts_headline_byid_opt,
								  ObjectIdGetDatum(getTSCurrentConfig(true)),
										PG_GETARG_DATUM(0),
										PG_GETARG_DATUM(1)));
}

Datum
ts_headline_opt(PG_FUNCTION_ARGS)
{
	PG_RETURN_DATUM(DirectFunctionCall4(ts_headline_byid_opt,
								  ObjectIdGetDatum(getTSCurrentConfig(true)),
										PG_GETARG_DATUM(0),
										PG_GETARG_DATUM(1),
										PG_GETARG_DATUM(2)));
}
