/*
** Zabbix
** Copyright (C) 2001-2021 Zabbix SIA
**
** 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
**/

#include "common.h"
#include "db.h"
#include "dbupgrade.h"
#include "dbupgrade_macros.h"
#include "log.h"

/******************************************************************************
 *                                                                            *
 * Function: str_rename_macro                                                 *
 *                                                                            *
 * Purpose: rename macros in the string                                       *
 *                                                                            *
 * Parameters: in        - [IN] the input string                              *
 *             oldmacro  - [IN] the macro to rename                           *
 *             newmacro  - [IN] the new macro name                            *
 *             out       - [IN/OUT] the string with renamed macros            *
 *             out_alloc - [IN/OUT] the output buffer size                    *
 *                                                                            *
 * Return value: SUCCEED - macros were found and renamed                      *
 *               FAIL    - no target macros were found                        *
 *                                                                            *
 * Comments: If the oldmacro is found in input string then all occurrences of *
 *           it are replaced with the new macro in the output string.         *
 *           Otherwise the output string is not changed.                      *
 *                                                                            *
 ******************************************************************************/
static int	str_rename_macro(const char *in, const char *oldmacro, const char *newmacro, char **out,
		size_t *out_alloc)
{
	zbx_token_t	token;
	int		pos = 0, ret = FAIL;
	size_t		out_offset = 0, newmacro_len;

	newmacro_len = strlen(newmacro);
	zbx_strcpy_alloc(out, out_alloc, &out_offset, in);
	out_offset++;

	for (; SUCCEED == zbx_token_find(*out, pos, &token, ZBX_TOKEN_SEARCH_BASIC); pos++)
	{
		switch (token.type)
		{
			case ZBX_TOKEN_MACRO:
				pos = token.loc.r;
				if (0 == strncmp(*out + token.loc.l, oldmacro, token.loc.r - token.loc.l + 1))
				{
					pos += zbx_replace_mem_dyn(out, out_alloc, &out_offset, token.loc.l,
							token.loc.r - token.loc.l + 1, newmacro, newmacro_len);
					ret = SUCCEED;
				}
				break;

			case ZBX_TOKEN_USER_MACRO:
			case ZBX_TOKEN_SIMPLE_MACRO:
				pos = token.loc.r;
				break;
		}
	}

	return ret;
}

/******************************************************************************
 *                                                                            *
 * Function: db_rename_macro                                                  *
 *                                                                            *
 * Purpose: rename macro in the specified database fields                     *
 *                                                                            *
 * Parameters: result     - [IN] database query with fields to replace. First *
 *                               field is table id field, following with      *
 *                               the target fields listed in fields parameter *
 *             table      - [IN] the target table name                        *
 *             pkey       - [IN] the primary key field name                   *
 *             fields     - [IN] the table fields to check for macros and     *
 *                               rename if found                              *
 *             fields_num - [IN] the number of fields to check                *
 *             oldmacro   - [IN] the macro to rename                          *
 *             newmacro   - [IN] the new macro name                           *
 *                                                                            *
 * Return value: SUCCEED  - macros were renamed successfully                  *
 *               FAIL     - database error occurred                           *
 *                                                                            *
 ******************************************************************************/
int	db_rename_macro(DB_RESULT result, const char *table, const char *pkey, zbx_field_len_t *fields, int fields_num,
		const char *oldmacro, const char *newmacro)
{
	DB_ROW		row;
	char		*sql = 0, *value = NULL, *value_esc;
	size_t		sql_alloc = 4096, sql_offset = 0, field_alloc = 0, old_offset;
	int		i, ret = SUCCEED;
	zbx_field_len_t	*field;

	sql = zbx_malloc(NULL, sql_alloc);

	DBbegin_multiple_update(&sql, &sql_alloc, &sql_offset);

	while (NULL != (row = DBfetch(result)))
	{
		old_offset = sql_offset;

		for (i = 0; i < fields_num; i++)
		{
			field = fields + i;

			if (SUCCEED == str_rename_macro(row[i + 1], oldmacro, newmacro, &value, &field_alloc))
			{
				if (0 != field->max_len && zbx_strlen_utf8(value) > field->max_len)
				{
					zabbix_log(LOG_LEVEL_WARNING, "cannot rename macros in table \"%s\" row "
							"\"%s:%s\" field \"%s\": value is too long",
							table, pkey, row[0], field->field_name);
					continue;
				}

				value_esc = DBdyn_escape_string(value);

				if (old_offset == sql_offset)
					zbx_snprintf_alloc(&sql, &sql_alloc, &sql_offset, "update %s set ", table);
				else
					zbx_chrcpy_alloc(&sql, &sql_alloc, &sql_offset, ',');

				zbx_snprintf_alloc(&sql, &sql_alloc, &sql_offset, "%s='%s'", fields[i].field_name,
						value_esc);

				zbx_free(value_esc);
			}
		}

		if (old_offset != sql_offset)
		{
			zbx_snprintf_alloc(&sql, &sql_alloc, &sql_offset, " where %s=%s;\n", pkey, row[0]);
			if (SUCCEED != (ret = DBexecute_overflowed_sql(&sql, &sql_alloc, &sql_offset)))
				goto out;
		}
	}

	DBend_multiple_update(&sql, &sql_alloc, &sql_offset);

	if (16 < sql_offset && ZBX_DB_OK > DBexecute("%s", sql))
		ret = FAIL;
out:
	zbx_free(value);
	zbx_free(sql);

	return ret;
}