/*
 * CallWeaver -- An open source telephony toolkit.
 *
 * Copyright (C) 2004 - 2005, Andy Powell 
 *
 * Updated by Mark Spencer <markster@digium.com>
 *
 * See http://www.callweaver.org for more information about
 * the CallWeaver project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Maths relatad dialplan functions
 * 
 */
#ifdef HAVE_CONFIG_H
#include "confdefs.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

#include "callweaver.h"

CALLWEAVER_FILE_VERSION("$HeadURL$", "$Revision$")

#include "callweaver/module.h"
#include "callweaver/channel.h"
#include "callweaver/pbx.h"
#include "callweaver/logger.h"
#include "callweaver/utils.h"
#include "callweaver/app.h"
#include "callweaver/config.h"


static void *math_function;
static const char *math_func_name = "MATH";
static const char *math_func_synopsis = "Performs Mathematical Functions";
static const char *math_func_syntax = "MATH(number1 op number2[, type_of_result])";
static const char *math_func_desc =
	"Perform calculation on number 1 to number 2. Valid ops are: \n"
        "    +,-,/,*,%,<,>,>=,<=,==\n"
	"and behave as their C equivalents.\n"
	"<type_of_result> - wanted type of result:\n"
	"	f, float - float(default)\n"
	"	i, int - integer,\n"
	"	h, hex - hex,\n"
	"	c, char - char\n"
	"Example: Set(i=${MATH(123 % 16, int)}) - sets var i=11";


enum TypeOfFunctions
{
    ADDFUNCTION,
    DIVIDEFUNCTION,
    MULTIPLYFUNCTION,
    SUBTRACTFUNCTION,
    MODULUSFUNCTION,

    GTFUNCTION,
    LTFUNCTION,
    GTEFUNCTION,
    LTEFUNCTION,
    EQFUNCTION
};

enum TypeOfResult
{
    FLOAT_RESULT,
    INT_RESULT,
    HEX_RESULT,
    CHAR_RESULT
};


static char *builtin_function_math(struct cw_channel *chan, int argc, char **argv, char *buf, size_t len) 
{
	double fnum1;
	double fnum2;
	double ftmp = 0;
	char *op;
	int iaction=-1;
	int type_of_result=FLOAT_RESULT;

	/* dunno, big calulations :D */
	char user_result[30];

	char *mvalue1, *mvalue2=NULL, *mtype_of_result;

	if (argc != 2 || !argv[0][0] || !argv[1][0]) {
		cw_log(LOG_ERROR, "Syntax: %s\n", math_func_syntax);
		return NULL;
	}

	mvalue1 = argv[0];
	
	if ((op = strchr(mvalue1, '+'))) {
		iaction = ADDFUNCTION;
		*op = '\0';
	} else if ((op = strchr(mvalue1, '-'))) {
		iaction = SUBTRACTFUNCTION;
		*op = '\0';
	} else if ((op = strchr(mvalue1, '*'))) {
		iaction = MULTIPLYFUNCTION;
		*op = '\0';
	} else if ((op = strchr(mvalue1, '/'))) {
		iaction = DIVIDEFUNCTION;
		*op = '\0';
	} else if ((op = strchr(mvalue1, '%'))) {
		iaction = MODULUSFUNCTION;
		*op = '\0';
	} else if ((op = strchr(mvalue1, '>'))) {
		iaction = GTFUNCTION;
		*op = '\0';
		if (*(op+1) == '=') {
			*++op = '\0';
			iaction = GTEFUNCTION;
		}
	} else if ((op = strchr(mvalue1, '<'))) {
		iaction = LTFUNCTION;
		*op = '\0';
		if (*(op+1) == '=') {
			*++op = '\0';
			iaction = LTEFUNCTION;
		}
	} else if ((op = strchr(mvalue1, '='))) {
		iaction = GTFUNCTION;
		*op = '\0';
		if (*(op+1) == '=') {
			*++op = '\0';
			iaction = EQFUNCTION;
		} else
			op = NULL;
	} 
	
	if (op) 
		mvalue2 = op + 1;

	/* detect wanted type of result */
	mtype_of_result = argv[1];
	if (mtype_of_result)
	{
		if (!strcasecmp(mtype_of_result,"float") || !strcasecmp(mtype_of_result,"f"))
			type_of_result=FLOAT_RESULT;
		else if (!strcasecmp(mtype_of_result,"int") || !strcasecmp(mtype_of_result,"i"))
			type_of_result=INT_RESULT;
		else if (!strcasecmp(mtype_of_result,"hex") || !strcasecmp(mtype_of_result,"h"))
			type_of_result=HEX_RESULT;
		else if (!strcasecmp(mtype_of_result,"char") || !strcasecmp(mtype_of_result,"c"))
			type_of_result=CHAR_RESULT;
		else
		{
			cw_log(LOG_WARNING, "Unknown type of result requested '%s'.\n", mtype_of_result);
			return NULL;
		}
	}
	
	if (!mvalue1 || !mvalue2) {
		cw_log(LOG_WARNING, "Supply all the parameters - just this once, please\n");
		return NULL;
	}

	if (sscanf(mvalue1, "%lf", &fnum1) != 1) {
		cw_log(LOG_WARNING, "'%s' is not a valid number\n", mvalue1);
		return NULL;
	}

	if (sscanf(mvalue2, "%lf", &fnum2) != 1) {
		cw_log(LOG_WARNING, "'%s' is not a valid number\n", mvalue2);
		return NULL;
	}

	switch (iaction) {
	case ADDFUNCTION :
		ftmp = fnum1 + fnum2;
		break;
	case DIVIDEFUNCTION :
		if (fnum2 <= 0)
			ftmp = 0.0L; /* can't do a divide by 0 */
		else
			ftmp = (fnum1 / fnum2);
		break;
	case MULTIPLYFUNCTION :
		ftmp = (fnum1 * fnum2);
		break;
	case SUBTRACTFUNCTION :
		ftmp = (fnum1 - fnum2);
		break;
	case MODULUSFUNCTION :
	{
		int inum1 = fnum1;
		int inum2 = fnum2;
			
		ftmp = (inum1 % inum2);
		
		break;
	}
	case GTFUNCTION :
		cw_copy_string (user_result, (fnum1 > fnum2)?"TRUE":"FALSE", sizeof (user_result));
		break;
	case LTFUNCTION :
		cw_copy_string (user_result, (fnum1 < fnum2)?"TRUE":"FALSE", sizeof (user_result));
		break;
	case GTEFUNCTION :
		cw_copy_string (user_result, (fnum1 >= fnum2)?"TRUE":"FALSE", sizeof (user_result));
		break;
	case LTEFUNCTION :
		cw_copy_string (user_result, (fnum1 <= fnum2)?"TRUE":"FALSE", sizeof (user_result));
		break;					
	case EQFUNCTION :
		cw_copy_string (user_result, (fnum1 == fnum2)?"TRUE":"FALSE", sizeof (user_result));
		break;
	default :
		cw_log(LOG_WARNING, "Something happened that neither of us should be proud of %d\n", iaction);
		return NULL;
	}

	if (iaction < GTFUNCTION || iaction > EQFUNCTION) {
	    if (type_of_result == FLOAT_RESULT)
		    snprintf(user_result, sizeof(user_result), "%lf", ftmp);
	    else if (type_of_result == INT_RESULT)
		    snprintf(user_result, sizeof(user_result), "%i", (int) ftmp);
	    else if (type_of_result == HEX_RESULT)
		snprintf(user_result, sizeof(user_result), "%x", (unsigned int) ftmp);
	    else if (type_of_result == CHAR_RESULT)
		snprintf(user_result, sizeof(user_result), "%c", (unsigned char) ftmp);
	}
		
	cw_copy_string(buf, user_result, len);
	
	return buf;
}


static char *tdesc = "math functions";

int unload_module(void)
{
        return cw_unregister_function(math_function);
}

int load_module(void)
{
        math_function = cw_register_function(math_func_name, builtin_function_math, NULL, math_func_synopsis, math_func_syntax, math_func_desc);
	return 0;
}

char *description(void)
{
	return tdesc;
}

int usecount(void)
{
	return 0;
}

/*
Local Variables:
mode: C
c-file-style: "linux"
indent-tabs-mode: nil
End:
*/