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#include "precomp.hpp"

namespace cv
{

////////////////////// KeyPoint //////////////////////

size_t KeyPoint::hash() const
{
    size_t _Val = 2166136261U, scale = 16777619U;
    Cv32suf u;
    u.f = pt.x; _Val = (scale * _Val) ^ u.u;
    u.f = pt.y; _Val = (scale * _Val) ^ u.u;
    u.f = size; _Val = (scale * _Val) ^ u.u;
    u.f = angle; _Val = (scale * _Val) ^ u.u;
    u.f = response; _Val = (scale * _Val) ^ u.u;
    _Val = (scale * _Val) ^ ((size_t) octave);
    _Val = (scale * _Val) ^ ((size_t) class_id);
    return _Val;
}

void KeyPoint::convert(const std::vector<KeyPoint>& keypoints, std::vector<Point2f>& points2f,
                       const std::vector<int>& keypointIndexes)
{
    CV_INSTRUMENT_REGION();

    if( keypointIndexes.empty() )
    {
        points2f.resize( keypoints.size() );
        for( size_t i = 0; i < keypoints.size(); i++ )
            points2f[i] = keypoints[i].pt;
    }
    else
    {
        points2f.resize( keypointIndexes.size() );
        for( size_t i = 0; i < keypointIndexes.size(); i++ )
        {
            int idx = keypointIndexes[i];
            if( idx >= 0 )
                points2f[i] = keypoints[idx].pt;
            else
            {
                CV_Error( CV_StsBadArg, "keypointIndexes has element < 0. TODO: process this case" );
                //points2f[i] = Point2f(-1, -1);
            }
        }
    }
}

void KeyPoint::convert( const std::vector<Point2f>& points2f, std::vector<KeyPoint>& keypoints,
                        float size, float response, int octave, int class_id )
{
    CV_INSTRUMENT_REGION();

    keypoints.resize(points2f.size());
    for( size_t i = 0; i < points2f.size(); i++ )
        keypoints[i] = KeyPoint(points2f[i], size, -1, response, octave, class_id);
}

float KeyPoint::overlap( const KeyPoint& kp1, const KeyPoint& kp2 )
{
    float a = kp1.size * 0.5f;
    float b = kp2.size * 0.5f;
    float a_2 = a * a;
    float b_2 = b * b;

    Point2f p1 = kp1.pt;
    Point2f p2 = kp2.pt;
    float c = (float)norm( p1 - p2 );

    float ovrl = 0.f;

    // one circle is completely encovered by the other => no intersection points!
    if( std::min( a, b ) + c <= std::max( a, b ) )
        return std::min( a_2, b_2 ) / std::max( a_2, b_2 );

    if( c < a + b ) // circles intersect
    {
        float c_2 = c * c;
        float cosAlpha = ( b_2 + c_2 - a_2 ) / ( kp2.size * c );
        float cosBeta  = ( a_2 + c_2 - b_2 ) / ( kp1.size * c );
        float alpha = acos( cosAlpha );
        float beta = acos( cosBeta );
        float sinAlpha = sin(alpha);
        float sinBeta  = sin(beta);

        float segmentAreaA = a_2 * beta;
        float segmentAreaB = b_2 * alpha;

        float triangleAreaA = a_2 * sinBeta * cosBeta;
        float triangleAreaB = b_2 * sinAlpha * cosAlpha;

        float intersectionArea = segmentAreaA + segmentAreaB - triangleAreaA - triangleAreaB;
        float unionArea = (a_2 + b_2) * (float)CV_PI - intersectionArea;

        ovrl = intersectionArea / unionArea;
    }

    return ovrl;
}

////////////////////// RotatedRect //////////////////////

RotatedRect::RotatedRect(const Point2f& _point1, const Point2f& _point2, const Point2f& _point3)
{
    Point2f _center = 0.5f * (_point1 + _point3);
    Vec2f vecs[2];
    vecs[0] = Vec2f(_point1 - _point2);
    vecs[1] = Vec2f(_point2 - _point3);
    double x = std::max(norm(_point1), std::max(norm(_point2), norm(_point3)));
    double a = std::min(norm(vecs[0]), norm(vecs[1]));
    // check that given sides are perpendicular
    CV_Assert( std::fabs(vecs[0].ddot(vecs[1])) * a <= FLT_EPSILON * 9 * x * (norm(vecs[0]) * norm(vecs[1])) );

    // wd_i stores which vector (0,1) or (1,2) will make the width
    // One of them will definitely have slope within -1 to 1
    int wd_i = 0;
    if( std::fabs(vecs[1][1]) < std::fabs(vecs[1][0]) ) wd_i = 1;
    int ht_i = (wd_i + 1) % 2;

    float _angle = std::atan(vecs[wd_i][1] / vecs[wd_i][0]) * 180.0f / (float) CV_PI;
    float _width = (float) norm(vecs[wd_i]);
    float _height = (float) norm(vecs[ht_i]);

    center = _center;
    size = Size2f(_width, _height);
    angle = _angle;
}

void RotatedRect::points(Point2f pt[]) const
{
    double _angle = angle*CV_PI/180.;
    float b = (float)cos(_angle)*0.5f;
    float a = (float)sin(_angle)*0.5f;

    pt[0].x = center.x - a*size.height - b*size.width;
    pt[0].y = center.y + b*size.height - a*size.width;
    pt[1].x = center.x + a*size.height - b*size.width;
    pt[1].y = center.y - b*size.height - a*size.width;
    pt[2].x = 2*center.x - pt[0].x;
    pt[2].y = 2*center.y - pt[0].y;
    pt[3].x = 2*center.x - pt[1].x;
    pt[3].y = 2*center.y - pt[1].y;
}

void RotatedRect::points(std::vector<Point2f>& pts) const {
    pts.resize(4);
    points(pts.data());
}

Rect RotatedRect::boundingRect() const
{
    Point2f pt[4];
    points(pt);
    Rect r(cvFloor(std::min(std::min(std::min(pt[0].x, pt[1].x), pt[2].x), pt[3].x)),
           cvFloor(std::min(std::min(std::min(pt[0].y, pt[1].y), pt[2].y), pt[3].y)),
           cvCeil(std::max(std::max(std::max(pt[0].x, pt[1].x), pt[2].x), pt[3].x)),
           cvCeil(std::max(std::max(std::max(pt[0].y, pt[1].y), pt[2].y), pt[3].y)));
    r.width -= r.x - 1;
    r.height -= r.y - 1;
    return r;
}


Rect_<float> RotatedRect::boundingRect2f() const
{
    Point2f pt[4];
    points(pt);
    Rect_<float> r(Point_<float>(min(min(min(pt[0].x, pt[1].x), pt[2].x), pt[3].x), min(min(min(pt[0].y, pt[1].y), pt[2].y), pt[3].y)),
                   Point_<float>(max(max(max(pt[0].x, pt[1].x), pt[2].x), pt[3].x), max(max(max(pt[0].y, pt[1].y), pt[2].y), pt[3].y)));
    return r;
}

} // cv
