/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011      Sandro Santilli <strk@kbt.io>
 * Copyright (C) 2001-2002 Vivid Solutions Inc.
 * Copyright (C) 2005 Refractions Research Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************
 *
 * Last port: algorithm/HCoordinate.java r386 (JTS-1.12+)
 *
 **********************************************************************/

#include <geos/algorithm/HCoordinate.h>
#include <geos/algorithm/NotRepresentableException.h>
#include <geos/geom/Coordinate.h>

#include <memory>
#include <cmath>
#include <limits>
#include <iostream>
#include <iomanip>

#ifndef GEOS_DEBUG
#define GEOS_DEBUG 0
#endif

using namespace geos::geom;

namespace geos {
namespace algorithm { // geos.algorithm

/*public static*/
void
HCoordinate::intersection(const Coordinate& p1, const Coordinate& p2,
                          const Coordinate& q1, const Coordinate& q2, Coordinate& ret)
{

#if GEOS_DEBUG
    std::cerr << __FUNCTION__ << ":" << std::endl
         << std::setprecision(20)
         << " p1: " << p1 << std::endl
         << " p2: " << p2 << std::endl
         << " q1: " << q1 << std::endl
         << " q2: " << q2 << std::endl;
#endif

    // unrolled computation

    double px = p1.y - p2.y;
    double py = p2.x - p1.x;
    double pw = p1.x * p2.y - p2.x * p1.y;

    double qx = q1.y - q2.y;
    double qy = q2.x - q1.x;
    double qw = q1.x * q2.y - q2.x * q1.y;

    double x = py * qw - qy * pw;
    double y = qx * pw - px * qw;
    double w = px * qy - qx * py;

    double xInt = x / w;
    double yInt = y / w;

    if((!std::isfinite(xInt)) || (!std::isfinite(yInt))) {
        throw NotRepresentableException();
    }

    ret = Coordinate(xInt, yInt);
}

/*public*/
HCoordinate::HCoordinate()
    :
    x(0.0),
    y(0.0),
    w(1.0)
{
}

/*public*/
HCoordinate::HCoordinate(double _x, double _y, double _w)
    :
    x(_x),
    y(_y),
    w(_w)
{
}

/*public*/
HCoordinate::HCoordinate(const Coordinate& p)
    :
    x(p.x),
    y(p.y),
    w(1.0)
{
}

/*public*/
HCoordinate::HCoordinate(const Coordinate& p1, const Coordinate& p2)
    :
    // optimization when it is known that w = 1
    x(p1.y - p2.y),
    y(p2.x - p1.x),
    w(p1.x * p2.y - p2.x * p1.y)
{
}

/*public*/
HCoordinate::HCoordinate(const Coordinate& p1, const Coordinate& p2,
                         const Coordinate& q1, const Coordinate& q2)
{
    // unrolled computation
    double px = p1.y - p2.y;
    double py = p2.x - p1.x;
    double pw = p1.x * p2.y - p2.x * p1.y;

    double qx = q1.y - q2.y;
    double qy = q2.x - q1.x;
    double qw = q1.x * q2.y - q2.x * q1.y;

    x = py * qw - qy * pw;
    y = qx * pw - px * qw;
    w = px * qy - qx * py;
}

/*public*/
HCoordinate::HCoordinate(const HCoordinate& p1, const HCoordinate& p2)
    :
    x(p1.y * p2.w - p2.y * p1.w),
    y(p2.x * p1.w - p1.x * p2.w),
    w(p1.x * p2.y - p2.x * p1.y)
{
}

/*public*/
double
HCoordinate::getX() const
{
    double a = x / w;
    if(!std::isfinite(a)) {
        throw NotRepresentableException();
    }
    return a;
}

/*public*/
double
HCoordinate::getY() const
{
    double a = y / w;
    if(!std::isfinite(a)) {
        throw  NotRepresentableException();
    }
    return a;
}

/*public*/
void
HCoordinate::getCoordinate(Coordinate& ret) const
{
    ret = Coordinate(static_cast<double>(getX()), static_cast<double>(getY()));
}

std::ostream&
operator<< (std::ostream& o, const HCoordinate& c)
{
    return o << "(" << c.x << ", "
           << c.y << ") [w: " << c.w << "]";
}

} // namespace geos.algorithm
} // namespace geos

