/* This file is part of guile-sql.
   Copyright (C) 2002 Sergey Poznyakoff

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <guile-sql.h>
#include <libpq-fe.h>

SCM
s_pgsql_mark(struct sql_connect *conn)
{
	return SCM_BOOL_F;
}

scm_sizet
s_pgsql_free(struct sql_connect *conn)
{
	PGconn *pgconn = (PGconn*) conn->data;
	if (!pgconn)
		return 0;
	PQfinish(pgconn);
	return sizeof(pgconn);
}

SCM
s_pgsql_connect (char *hostname, int port,
		 char *dbname, char *user, char *pass, char *why)
{
	PGconn *pgconn;
	char buf[24];
	SCM smob;
	struct sql_connect *conn;
	
	snprintf(buf, sizeof buf, "%d", port);
	pgconn = PQsetdbLogin(hostname, buf, NULL, NULL, dbname, user, pass);
	if (PQstatus(pgconn) == CONNECTION_BAD) 
		return SCM_BOOL_F;

	smob = sql_connect_create("pgsql");
	conn = (struct sql_connect *)SCM_CDR(smob);
	conn->data = pgconn;
	return smob;
}

SCM
result_to_list(PGresult *res)
{
	int i, j;
	int ntuples = PQntuples(res);
	int nfields = PQnfields(res);
	SCM row_head = SCM_EOL, row_tail;

	for (i = 0; i < ntuples; i++) {
		SCM new_row;
		SCM head = SCM_EOL, tail;

		for (j = 0; j < nfields; j++) {
			SCM new_elt;
			char *val = PQgetvalue(res, i, j);
			SCM_NEWCELL(new_elt);
			SCM_SETCAR(new_elt, scm_makfrom0str(val));
			if (head == SCM_EOL)
				head = new_elt;
			else
				SCM_SETCDR(tail, new_elt);
			tail = new_elt;
		}

		if (head != SCM_EOL)
			SCM_SETCDR(tail, SCM_EOL);
			
		SCM_NEWCELL(new_row);
		SCM_SETCAR(new_row, head);
			
		if (row_head == SCM_EOL) 
			row_head = new_row;
		else 
			SCM_SETCDR(row_tail, new_row);
		row_tail = new_row;
	}
	if (row_head != SCM_EOL)
		SCM_SETCDR(row_tail, SCM_EOL);
	return row_head;
}

SCM
s_pgsql_query(struct sql_connect *conn, char *query)
{
	PGconn *pgconn = (PGconn*) conn->data;
	PGresult       *res;
	SCM cell;
	ExecStatusType stat;
	
	res = PQexec(pgconn, query);
	if (!res) 
		scm_misc_error("s_mgsql_query",
			       "pgSQL error: ~S",
			       SCM_LIST1(scm_makfrom0str(PQerrorMessage(pgconn))));

	stat = PQresultStatus(res);

	switch (stat) {
	case PGRES_COMMAND_OK:
		/* Successful completion of a command returning no data */
		cell = scm_makenum(strtoul(PQcmdTuples(res), NULL, 0));
		break;
	case PGRES_TUPLES_OK:
		/* The query successfully executed */
		cell = result_to_list(res);
		PQclear(res);
		break;
	default:
		scm_misc_error("s_mgsql_query",
			       "pgSQL error: ~S",
			       SCM_LIST1(scm_makfrom0str(PQresStatus(stat))));
	}

	return cell;
}

void
s_pgsql_close(struct sql_connect *conn)
{
	PGconn *pgconn = (PGconn*) conn->data;
	if (!pgconn)
		return;
	PQfinish(pgconn);
	conn->data = NULL;
}

struct sql_iface pgsql_iface = {
	"pgsql",
	s_pgsql_mark,
	s_pgsql_free,
	s_pgsql_connect,
	s_pgsql_close,
	s_pgsql_query,
};