/*
 * Copyright 2006-2009, Haiku.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Stephan Aßmus <superstippi@gmx.de>
 */

#include "support.h"

#include <math.h>
#include <stdio.h>
#include <string.h>

#include <DataIO.h>
#include <Point.h>
#include <String.h>


// point_line_distance
double
point_line_distance(double x1, double y1, double x2, double y2, double x,
	double y)
{
	double dx = x2 - x1;
	double dy = y2 - y1;
	return ((x - x2) * dy - (y - y2) * dx) / sqrt(dx * dx + dy * dy);
}


// point_line_distance
double
point_line_distance(BPoint point, BPoint pa, BPoint pb)
{
	// first figure out if point is between segment start and end points
	double a = point_point_distance(point, pb);
	double b = point_point_distance(point, pa);
	double c = point_point_distance(pa, pb);

	float currentDist = min_c(a, b);

	if (a > 0.0 && b > 0.0) {
		double alpha = acos((b*b + c*c - a*a) / (2*b*c));
		double beta = acos((a*a + c*c - b*b) / (2*a*c));

		if (alpha <= M_PI_2 && beta <= M_PI_2) {
			currentDist = fabs(point_line_distance(pa.x, pa.y, pb.x, pb.y,
				point.x, point.y));
		}
	}

	return currentDist;
}


// calc_angle
double
calc_angle(BPoint origin, BPoint from, BPoint to, bool degree)
{
	double angle = 0.0;

	double d = point_line_distance(from.x, from.y, origin.x, origin.y,
		to.x, to.y);
	if (d != 0.0) {
		double a = point_point_distance(from, to);
		double b = point_point_distance(from, origin);
		double c = point_point_distance(to, origin);
		if (a > 0.0 && b > 0.0 && c > 0.0) {
			angle = acos((b*b + c*c - a*a) / (2.0*b*c));

			if (d < 0.0)
				angle = -angle;

			if (degree)
				angle = angle * 180.0 / M_PI;
		}
	}
	return angle;
}


// write_string
status_t
write_string(BPositionIO* stream, BString& string)
{
	if (!stream)
		return B_BAD_VALUE;

	ssize_t written = stream->Write(string.String(), string.Length());
	if (written > B_OK && written < string.Length())
		written = B_ERROR;
	string.SetTo("");
	return written;
}


// append_float
void
append_float(BString& string, float n, int32 maxDigits)
{
	int32 rounded = n >= 0.0 ? (int32)fabs(floorf(n)) : (int32)fabs(ceilf(n));

	if (n < 0.0) {
		string << "-";
		n *= -1.0;
	}
	string << rounded;

	if ((float)rounded != n) {
		// find out how many digits remain
		n = n - rounded;
		rounded = (int32)(n * pow(10, maxDigits));
		char tmp[maxDigits + 1];
		sprintf(tmp, "%0*" B_PRId32, (int)maxDigits, rounded);
		tmp[maxDigits] = 0;
		int32 digits = strlen(tmp);
		for (int32 i = strlen(tmp) - 1; i >= 0; i--) {
			if (tmp[i] == '0')
				digits--;
			else
				break;
		}
		// write after decimal
		if (digits > 0) {
			string << ".";
			for (int32 i = 0; i < digits; i++) {
				string << tmp[i];
			}
		}
	}
}


//// gauss
//double
//gauss(double f)
//{
//	// this aint' a real gauss function
///*	if (f >= -1.0 && f <= 1.0) {
//		if (f < -0.5) {
//			f = -1.0 - f;
//			return (2.0 * f*f);
//		}
//
//		if (f < 0.5)
//			return (1.0 - 2.0 * f*f);
//
//		f = 1.0 - f;
//		return (2.0 * f*f);
//	}*/
//	if (f > 0.0) {
//		if (f < 0.5)
//			return (1.0 - 2.0 * f*f);
//
//		f = 1.0 - f;
//		return (2.0 * f*f);
//	}
//	return 1.0;
//}