/*
 * utils.cpp
 *
 *  Created on: Oct 21, 2014
 *      Author: Alan Aguilar Sologuren
 */

#include <stdlib.h>
#include <stdarg.h>
#include "utils.h"

/**
 * \fn code_degree2radian
 * \brief Convert degree to radian
 */
double code_degree2radian(double val) {
	return (val * code_PI180);
}

/**
 * \fn code_radian2degree
 * \brief Convert radian to degree
 */
double code_radian2degree(double val) {
	return (val / code_PI180);
}

/**
 * \brief Convert NDEG (NMEA degree) to fractional degree
 */
double code_ndeg2degree(double val) {
    double deg = ((int)(val / 100));
    val = deg + (val - deg * 100) / 60;
    return val;
}

/**
 * \brief Convert fractional degree to NDEG (NMEA degree)
 */
double code_degree2ndeg(double val) {
    double int_part;
    double fra_part;
    fra_part = modf(val, &int_part);
    val = int_part * 100 + fra_part * 60;
    return val;
}

/**
 * \fn code_ndeg2radian
 * \brief Convert NDEG (NMEA degree) to radian
 */
double code_ndeg2radian(double val) {
	return code_degree2radian(code_ndeg2degree(val));
}

/**
 * \fn code_radian2ndeg
 * \brief Convert radian to NDEG (NMEA degree)
 */
double code_radian2ndeg(double val) {
	return code_degree2ndeg(code_radian2degree(val));
}

/**
 * \brief Calculate PDOP (Position Dilution Of Precision) factor
 */
double code_calc_pdop(double hdop, double vdop) {
	return sqrt(pow(hdop, 2) + pow(vdop, 2));
}

double code_dop2meters(double dop) {
	return (dop * code_DOP_FACTOR);
}

double code_meters2dop(double meters) {
	return (meters / code_DOP_FACTOR);
}

/**
 * \brief Calculate distance between two points
 * \return Distance in meters
 */
double code_distance(
		const nmeaPOS *from_pos,    /**< From position in radians */
        const nmeaPOS *to_pos       /**< To position in radians */
		)
{
    double dist = ((double)code_EARTHRADIUS_M) * acos(
        sin(to_pos->lat) * sin(from_pos->lat) +
        cos(to_pos->lat) * cos(from_pos->lat) * cos(to_pos->lon - from_pos->lon)
        );
    return dist;
}

/**
 * \brief Calculate distance between two points
 * This function uses an algorithm for an oblate spheroid earth model.
 * The algorithm is described here:
 * http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
 * \return Distance in meters
 */
double code_distance_ellipsoid(
        const nmeaPOS *from_pos,    /**< From position in radians */
        const nmeaPOS *to_pos,      /**< To position in radians */
        double *from_azimuth,       /**< (O) azimuth at "from" position in radians */
        double *to_azimuth          /**< (O) azimuth at "to" position in radians */
		)
{
	/* All variables */
	double f, a, b, sqr_a, sqr_b;
	double L, phi1, phi2, U1, U2, sin_U1, sin_U2, cos_U1, cos_U2;
	double sigma, sin_sigma, cos_sigma, cos_2_sigmam, sqr_cos_2_sigmam, sqr_cos_alpha, lambda, sin_lambda, cos_lambda, delta_lambda;
	int remaining_steps;
	double sqr_u, A, B, delta_sigma;

	/* Check input */
	NMEA_ASSERT(from_pos != 0);
	NMEA_ASSERT(to_pos != 0);

	if ((from_pos->lat == to_pos->lat) && (from_pos->lon == to_pos->lon))
	{ /* Identical points */
		if ( from_azimuth != 0 )
			*from_azimuth = 0;
		if ( to_azimuth != 0 )
			*to_azimuth = 0;
		return 0;
	} /* Identical points */

	/* Earth geometry */
	f = code_EARTH_FLATTENING;
	a = code_EARTH_SEMIMAJORAXIS_M;
	b = (1 - f) * a;
	sqr_a = a * a;
	sqr_b = b * b;

	/* Calculation */
	L = to_pos->lon - from_pos->lon;
	phi1 = from_pos->lat;
	phi2 = to_pos->lat;
	U1 = atan((1 - f) * tan(phi1));
	U2 = atan((1 - f) * tan(phi2));
	sin_U1 = sin(U1);
	sin_U2 = sin(U2);
	cos_U1 = cos(U1);
	cos_U2 = cos(U2);

	/* Initialize iteration */
	sigma = 0;
	sin_sigma = sin(sigma);
	cos_sigma = cos(sigma);
	cos_2_sigmam = 0;
	sqr_cos_2_sigmam = cos_2_sigmam * cos_2_sigmam;
	sqr_cos_alpha = 0;
	lambda = L;
	sin_lambda = sin(lambda);
	cos_lambda = cos(lambda);
	delta_lambda = lambda;
	remaining_steps = 20;

	while ((delta_lambda > 1e-12) && (remaining_steps > 0))
	{ /* Iterate */
		/* Variables */
		double tmp1, tmp2, tan_sigma, sin_alpha, cos_alpha, C, lambda_prev;

		/* Calculation */
		tmp1 = cos_U2 * sin_lambda;
		tmp2 = cos_U1 * sin_U2 - sin_U1 * cos_U2 * cos_lambda;
		sin_sigma = sqrt(tmp1 * tmp1 + tmp2 * tmp2);
		cos_sigma = sin_U1 * sin_U2 + cos_U1 * cos_U2 * cos_lambda;
		tan_sigma = sin_sigma / cos_sigma;
		sin_alpha = cos_U1 * cos_U2 * sin_lambda / sin_sigma;
		cos_alpha = cos(asin(sin_alpha));
		sqr_cos_alpha = cos_alpha * cos_alpha;
		cos_2_sigmam = cos_sigma - 2 * sin_U1 * sin_U2 / sqr_cos_alpha;
		sqr_cos_2_sigmam = cos_2_sigmam * cos_2_sigmam;
		C = f / 16 * sqr_cos_alpha * (4 + f * (4 - 3 * sqr_cos_alpha));
		lambda_prev = lambda;
		sigma = asin(sin_sigma);
		lambda = L +
			(1 - C) * f * sin_alpha
			* (sigma + C * sin_sigma * (cos_2_sigmam + C * cos_sigma * (-1 + 2 * sqr_cos_2_sigmam)));
		delta_lambda = lambda_prev - lambda;
		if ( delta_lambda < 0 ) delta_lambda = -delta_lambda;
		sin_lambda = sin(lambda);
		cos_lambda = cos(lambda);
		remaining_steps--;
	}  /* Iterate */

	/* More calculation  */
	sqr_u = sqr_cos_alpha * (sqr_a - sqr_b) / sqr_b;
	A = 1 + sqr_u / 16384 * (4096 + sqr_u * (-768 + sqr_u * (320 - 175 * sqr_u)));
	B = sqr_u / 1024 * (256 + sqr_u * (-128 + sqr_u * (74 - 47 * sqr_u)));
	delta_sigma = B * sin_sigma * (
		cos_2_sigmam + B / 4 * (
		cos_sigma * (-1 + 2 * sqr_cos_2_sigmam) -
		B / 6 * cos_2_sigmam * (-3 + 4 * sin_sigma * sin_sigma) * (-3 + 4 * sqr_cos_2_sigmam)
		));

	/* Calculate result */
	if ( from_azimuth != 0 )
	{
		double tan_alpha_1 = cos_U2 * sin_lambda / (cos_U1 * sin_U2 - sin_U1 * cos_U2 * cos_lambda);
		*from_azimuth = atan(tan_alpha_1);
	}
	if ( to_azimuth != 0 )
	{
		double tan_alpha_2 = cos_U1 * sin_lambda / (-sin_U1 * cos_U2 + cos_U1 * sin_U2 * cos_lambda);
		*to_azimuth = atan(tan_alpha_2);
	}

	return b * A * (sigma - delta_sigma);

}
/**
 * \brief Horizontal move of point position
 */
int code_move_horz(
		const nmeaPOS *start_pos,   /**< Start position in radians */
		nmeaPOS *end_pos,           /**< Result position in radians */
		double azimuth,             /**< Azimuth (degree) [0, 359] */
		double distance             /**< Distance (km) */
)
{
    nmeaPOS p1 = *start_pos;
    int RetVal = 1;

    distance /= code_EARTHRADIUS_KM; /* Angular distance covered on earth's surface */
    azimuth = code_degree2radian(azimuth);

    end_pos->lat = asin(
        sin(p1.lat) * cos(distance) + cos(p1.lat) * sin(distance) * cos(azimuth));
    end_pos->lon = p1.lon + atan2(
        sin(azimuth) * sin(distance) * cos(p1.lat), cos(distance) - sin(p1.lat) * sin(end_pos->lat));

    if(NMEA_POSIX(isnan)(end_pos->lat) || NMEA_POSIX(isnan)(end_pos->lon))
    {
        end_pos->lat = 0; end_pos->lon = 0;
        RetVal = 0;
    }

    return RetVal;
}

/**
 * \brief Horizontal move of point position
 * This function uses an algorithm for an oblate spheroid earth model.
 * The algorithm is described here:
 * http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
 */
int code_move_horz_ellipsoid(
	    const nmeaPOS *start_pos,   /**< Start position in radians */
	    nmeaPOS *end_pos,           /**< (O) Result position in radians */
	    double azimuth,             /**< Azimuth in radians */
	    double distance,            /**< Distance (km) */
	    double *end_azimuth         /**< (O) Azimuth at end position in radians */
)
{
	/* Variables */
	double f, a, b, sqr_a, sqr_b;
	double phi1, tan_U1, sin_U1, cos_U1, s, alpha1, sin_alpha1, cos_alpha1;
	double tan_sigma1, sigma1, sin_alpha, cos_alpha, sqr_cos_alpha, sqr_u, A, B;
	double sigma_initial, sigma, sigma_prev, sin_sigma, cos_sigma, cos_2_sigmam, sqr_cos_2_sigmam, delta_sigma;
	int remaining_steps;
	double tmp1, phi2, lambda, C, L;

	/* Check input */
	NMEA_ASSERT(start_pos != 0);
	NMEA_ASSERT(end_pos != 0);

	if (fabs(distance) < 1e-12)
	{ /* No move */
		*end_pos = *start_pos;
		if ( end_azimuth != 0 ) *end_azimuth = azimuth;
		return ! (NMEA_POSIX(isnan)(end_pos->lat) || NMEA_POSIX(isnan)(end_pos->lon));
	} /* No move */

	/* Earth geometry */
	f = code_EARTH_FLATTENING;
	a = code_EARTH_SEMIMAJORAXIS_M;
	b = (1 - f) * a;
	sqr_a = a * a;
	sqr_b = b * b;

	/* Calculation */
	phi1 = start_pos->lat;
	tan_U1 = (1 - f) * tan(phi1);
	cos_U1 = 1 / sqrt(1 + tan_U1 * tan_U1);
	sin_U1 = tan_U1 * cos_U1;
	s = distance;
	alpha1 = azimuth;
	sin_alpha1 = sin(alpha1);
	cos_alpha1 = cos(alpha1);
	tan_sigma1 = tan_U1 / cos_alpha1;
	sigma1 = atan2(tan_U1, cos_alpha1);
	sin_alpha = cos_U1 * sin_alpha1;
	sqr_cos_alpha = 1 - sin_alpha * sin_alpha;
	cos_alpha = sqrt(sqr_cos_alpha);
	sqr_u = sqr_cos_alpha * (sqr_a - sqr_b) / sqr_b;
	A = 1 + sqr_u / 16384 * (4096 + sqr_u * (-768 + sqr_u * (320 - 175 * sqr_u)));
	B = sqr_u / 1024 * (256 + sqr_u * (-128 + sqr_u * (74 - 47 * sqr_u)));

	/* Initialize iteration */
	sigma_initial = s / (b * A);
	sigma = sigma_initial;
	sin_sigma = sin(sigma);
	cos_sigma = cos(sigma);
	cos_2_sigmam = cos(2 * sigma1 + sigma);
	sqr_cos_2_sigmam = cos_2_sigmam * cos_2_sigmam;
	delta_sigma = 0;
	sigma_prev = 2 * code_PI;
	remaining_steps = 20;

	while ((fabs(sigma - sigma_prev) > 1e-12) && (remaining_steps > 0))
	{ /* Iterate */
		cos_2_sigmam = cos(2 * sigma1 + sigma);
		sqr_cos_2_sigmam = cos_2_sigmam * cos_2_sigmam;
		sin_sigma = sin(sigma);
		cos_sigma = cos(sigma);
		delta_sigma = B * sin_sigma * (
			 cos_2_sigmam + B / 4 * (
			 cos_sigma * (-1 + 2 * sqr_cos_2_sigmam) -
			 B / 6 * cos_2_sigmam * (-3 + 4 * sin_sigma * sin_sigma) * (-3 + 4 * sqr_cos_2_sigmam)
			 ));
		sigma_prev = sigma;
		sigma = sigma_initial + delta_sigma;
		remaining_steps --;
	} /* Iterate */

	/* Calculate result */
	tmp1 = (sin_U1 * sin_sigma - cos_U1 * cos_sigma * cos_alpha1);
	phi2 = atan2(
			sin_U1 * cos_sigma + cos_U1 * sin_sigma * cos_alpha1,
			(1 - f) * sqrt(sin_alpha * sin_alpha + tmp1 * tmp1)
			);
	lambda = atan2(
			sin_sigma * sin_alpha1,
			cos_U1 * cos_sigma - sin_U1 * sin_sigma * cos_alpha1
			);
	C = f / 16 * sqr_cos_alpha * (4 + f * (4 - 3 * sqr_cos_alpha));
	L = lambda -
		(1 - C) * f * sin_alpha * (
		sigma + C * sin_sigma *
		(cos_2_sigmam + C * cos_sigma * (-1 + 2 * sqr_cos_2_sigmam))
		);

	/* Result */
	end_pos->lon = start_pos->lon + L;
	end_pos->lat = phi2;
	if ( end_azimuth != 0 )
	{
		*end_azimuth = atan2(
			sin_alpha, -sin_U1 * sin_sigma + cos_U1 * cos_sigma * cos_alpha1
			);
	}
	return ! (NMEA_POSIX(isnan)(end_pos->lat) || NMEA_POSIX(isnan)(end_pos->lon));
}

/**
 * \brief Calculate control sum of binary buffer
 */
int code_calc_crc(const char *buff, int buff_sz)
{
    int chsum = 0,
        it;

    for(it = 0; it < buff_sz; ++it)
        chsum ^= (int)buff[it];

    return chsum;
}

/**
 * \brief Convert string to number
 */
int code_atoi(const char *str, int str_sz, int radix)
{
    char *tmp_ptr;
    char buff[NMEA_CONVSTR_BUF];
    int res = 0;

    if(str_sz < NMEA_CONVSTR_BUF)
    {
        memcpy(&buff[0], str, str_sz);
        buff[str_sz] = '\0';
        res = strtol(&buff[0], &tmp_ptr, radix);
    }

    return res;
}

/**
 * \brief Convert string to fraction number
 */
double code_atof(const char *str, int str_sz)
{
    char *tmp_ptr;
    char buff[NMEA_CONVSTR_BUF];
    double res = 0;

    if(str_sz < NMEA_CONVSTR_BUF)
    {
        memcpy(&buff[0], str, str_sz);
        buff[str_sz] = '\0';
        res = strtod(&buff[0], &tmp_ptr);
    }

    return res;
}

/**
 * \brief Formating string (like standart printf) with CRC tail (*CRC)
 */
int code_printf(char *buff, int buff_sz, const char *format, ...)
{
    int retval, add = 0;
    va_list arg_ptr;

    if(buff_sz <= 0)
        return 0;

    va_start(arg_ptr, format);

    retval = NMEA_POSIX(vsnprintf)(buff, buff_sz, format, arg_ptr);

    if(retval > 0)
    {
        add = NMEA_POSIX(snprintf)(
            buff + retval, buff_sz - retval, "*%02x\r\n",
            code_calc_crc(buff + 1, retval - 1));
    }

    retval += add;

    if(retval < 0 || retval > buff_sz)
    {
        memset(buff, ' ', buff_sz);
        retval = buff_sz;
    }

    va_end(arg_ptr);

    return retval;
}

/**
 * \brief Analyse string (specificate for NMEA sentences)
 */
int code_scanf(const char *buff, int buff_sz, const char *format, ...)
{
    const char *beg_tok;
    const char *end_buf = buff + buff_sz;

    va_list arg_ptr;
    int tok_type = NMEA_TOKS_COMPARE;
    int width = 0;
    const char *beg_fmt = 0;
    int snum = 0, unum = 0;

    int tok_count = 0;
    void *parg_target;

    va_start(arg_ptr, format);

    for(; *format && buff < end_buf; ++format)
    {
        switch(tok_type)
        {
        case NMEA_TOKS_COMPARE:
            if('%' == *format)
                tok_type = NMEA_TOKS_PERCENT;
            else if(*buff++ != *format)
                goto fail;
            break;
        case NMEA_TOKS_PERCENT:
            width = 0;
            beg_fmt = format;
            tok_type = NMEA_TOKS_WIDTH;
        case NMEA_TOKS_WIDTH:
            if(isdigit(*format))
                break;
            {
                tok_type = NMEA_TOKS_TYPE;
                if(format > beg_fmt)
                    width = code_atoi(beg_fmt, (int)(format - beg_fmt), 10);
            }
        case NMEA_TOKS_TYPE:
            beg_tok = buff;

            if(!width && ('c' == *format || 'C' == *format) && *buff != format[1])
                width = 1;

            if(width)
            {
                if(buff + width <= end_buf)
                    buff += width;
                else
                    goto fail;
            }
            else
            {
                if(!format[1] || (0 == (buff = (char *)memchr(buff, format[1], end_buf - buff))))
                    buff = end_buf;
            }

            if(buff > end_buf)
                goto fail;

            tok_type = NMEA_TOKS_COMPARE;
            tok_count++;

            parg_target = 0; width = (int)(buff - beg_tok);

            switch(*format)
            {
            case 'c':
            case 'C':
                parg_target = (void *)va_arg(arg_ptr, char *);
                if(width && 0 != (parg_target))
                    *((char *)parg_target) = *beg_tok;
                break;
            case 's':
            case 'S':
                parg_target = (void *)va_arg(arg_ptr, char *);
                if(width && 0 != (parg_target))
                {
                    memcpy(parg_target, beg_tok, width);
                    ((char *)parg_target)[width] = '\0';
                }
                break;
            case 'f':
            case 'g':
            case 'G':
            case 'e':
            case 'E':
                parg_target = (void *)va_arg(arg_ptr, double *);
                if(width && 0 != (parg_target))
                    *((double *)parg_target) = code_atof(beg_tok, width);
                break;
            };

            if(parg_target)
                break;
            if(0 == (parg_target = (void *)va_arg(arg_ptr, int *)))
                break;
            if(!width)
                break;

            switch(*format)
            {
            case 'd':
            case 'i':
                snum = code_atoi(beg_tok, width, 10);
                memcpy(parg_target, &snum, sizeof(int));
                break;
            case 'u':
                unum = code_atoi(beg_tok, width, 10);
                memcpy(parg_target, &unum, sizeof(unsigned int));
                break;
            case 'x':
            case 'X':
                unum = code_atoi(beg_tok, width, 16);
                memcpy(parg_target, &unum, sizeof(unsigned int));
                break;
            case 'o':
                unum = code_atoi(beg_tok, width, 8);
                memcpy(parg_target, &unum, sizeof(unsigned int));
                break;
            default:
                goto fail;
            };

            break;
        };
    }

fail:

    va_end(arg_ptr);

    return tok_count;
}


double nmeaGenerator::nmea_random(double min, double max)
{
    static double rand_max = RAND_MAX;
    double rand_val = rand();
    double bounds = max - min;
    return min + (rand_val * bounds) / rand_max;
}