// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2020
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
// https://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// Version: 4.0.2019.08.13

#pragma once

#include <Mathematics/DCPQuery.h>
#include <Mathematics/Rectangle.h>
#include <Mathematics/Vector3.h>

namespace WwiseGTE
{
    template <typename Real>
    class DCPQuery<Real, Vector3<Real>, Rectangle3<Real>>
    {
    public:
        struct Result
        {
            Real distance, sqrDistance;
            Real rectangleParameter[2];
            Vector3<Real> rectangleClosestPoint;
        };

        Result operator()(Vector3<Real> const& point, Rectangle3<Real> const& rectangle)
        {
            Result result;

            Vector3<Real> diff = rectangle.center - point;
            Real b0 = Dot(diff, rectangle.axis[0]);
            Real b1 = Dot(diff, rectangle.axis[1]);
            Real s0 = -b0, s1 = -b1;
            result.sqrDistance = Dot(diff, diff);

            if (s0 < -rectangle.extent[0])
            {
                s0 = -rectangle.extent[0];
            }
            else if (s0 > rectangle.extent[0])
            {
                s0 = rectangle.extent[0];
            }
            result.sqrDistance += s0 * (s0 + (Real)2 * b0);

            if (s1 < -rectangle.extent[1])
            {
                s1 = -rectangle.extent[1];
            }
            else if (s1 > rectangle.extent[1])
            {
                s1 = rectangle.extent[1];
            }
            result.sqrDistance += s1 * (s1 + (Real)2 * b1);

            // Account for numerical round-off error.
            if (result.sqrDistance < (Real)0)
            {
                result.sqrDistance = (Real)0;
            }

            result.distance = std::sqrt(result.sqrDistance);
            result.rectangleParameter[0] = s0;
            result.rectangleParameter[1] = s1;
            result.rectangleClosestPoint = rectangle.center;
            for (int i = 0; i < 2; ++i)
            {
                result.rectangleClosestPoint += result.rectangleParameter[i] * rectangle.axis[i];
            }
            return result;
        }
    };
}