/*
 * Copyright (c) 2017, brian
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef STANDARD
/* STANDARD is defined, don't use any mysql functions */
#include <string.h>
#ifdef __WIN__
typedef unsigned __int64 ulonglong; /* Microsofts 64 bit types */
typedef __int64 longlong;
#else
typedef unsigned long long ulonglong;
typedef long long longlong;
#endif /*__WIN__*/
#else
#include <my_global.h>
#include <my_sys.h>
#if defined(MYSQL_SERVER)
#include <m_string.h>
#else
/* when compiled as standalone */
#include <string.h>
#endif
#endif
#include <mysql.h>
#include <ctype.h>

#ifdef HAVE_DLOPEN

char *trim(char *str) {
	size_t len = 0;
	char *frontp = str;
	char *endp = NULL;

	if (str == NULL) {
		return NULL;
	}
	if (str[0] == '\0') {
		return str;
	}

	len = strlen(str);
	endp = str + len;

	/* Move the front and back pointers to address the first non-whitespace
	 * characters from each end.
	 */
	while (isspace((unsigned char) *frontp)) {
		++frontp;
	}
	if (endp != frontp) {
		while (isspace((unsigned char) *(--endp)) && endp != frontp) {
		}
	}

	if (str + len - 1 != endp)
		*(endp + 1) = '\0';
	else if (frontp != str && endp == frontp)
		*str = '\0';

	/* Shift the string so that it starts at str so that if it's dynamically
	 * allocated, we can still free it on the returned pointer.  Note the reuse
	 * of endp to mean the front of the string buffer now.
	 */
	endp = str;
	if (frontp != str) {
		while (*frontp) {
			*endp++ = *frontp++;
		}
		*endp = '\0';
	}


	return str;
}

my_bool ifempty_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
void ifempty_deinit(UDF_INIT *initid);
char* ifempty(UDF_INIT *initid __attribute__ ((unused)), UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *message __attribute__ ((unused)));

my_bool ifempty_init(UDF_INIT *initid, UDF_ARGS *args, char *message) {
	int i;

	//	if (args->arg_count == 0) {
	//		strcpy(message, "Function requires at least 1 argument, (string [, string... ])");
	//		return 1;
	//	}

	for (i = 0; i < args->arg_count; i++) {
		args->arg_type[i] = STRING_RESULT;
	}

	initid->maybe_null = 1; //can return null

	return 0;
}

char* ifempty(UDF_INIT *initid __attribute__ ((unused)), UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *message __attribute__ ((unused))) {
	int i;
	char* Value;

	for (i = 0; i < args->arg_count; i++) {
		Value = args->args[i];

		if (Value == NULL)
			continue;

		if (args->lengths[i] == 0)
			continue;

		if (strlen(trim(Value)) == 0)
			continue;

		*length = strlen(Value);
		return Value;
	}

	*is_null = 1;
	return '\0';
}

#endif /* HAVE_DLOPEN */