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#ifndef __OPENCV_FAST_NLMEANS_DENOISING_INVOKER_COMMONS_HPP__
#define __OPENCV_FAST_NLMEANS_DENOISING_INVOKER_COMMONS_HPP__

using namespace cv;

template <typename T> static inline int calcDist(const T a, const T b);

template <> inline int calcDist(const uchar a, const uchar b) {
    return (a-b) * (a-b);
}

template <> inline int calcDist(const Vec2b a, const Vec2b b) {
    return (a[0]-b[0])*(a[0]-b[0]) + (a[1]-b[1])*(a[1]-b[1]);
}

template <> inline int calcDist(const Vec3b a, const Vec3b b) {
    return (a[0]-b[0])*(a[0]-b[0]) + (a[1]-b[1])*(a[1]-b[1]) + (a[2]-b[2])*(a[2]-b[2]);
}

template <typename T> static inline int calcDist(const Mat& m, int i1, int j1, int i2, int j2) {
    const T a = m.at<T>(i1, j1);
    const T b = m.at<T>(i2, j2);
    return calcDist<T>(a,b);
}

template <typename T> static inline int calcUpDownDist(T a_up, T a_down, T b_up, T b_down) {
    return calcDist(a_down,b_down) - calcDist(a_up, b_up);
}

template <> inline int calcUpDownDist(uchar a_up, uchar a_down, uchar  b_up, uchar b_down) {
    int A = a_down - b_down;
    int B = a_up - b_up;
    return (A-B)*(A+B);
}

template <typename T> static inline void incWithWeight(int* estimation, int weight, T p);

template <> inline void incWithWeight(int* estimation, int weight, uchar p) {
    estimation[0] += weight * p;
}

template <> inline void incWithWeight(int* estimation, int weight, Vec2b p) {
    estimation[0] += weight * p[0];
    estimation[1] += weight * p[1];
}

template <> inline void incWithWeight(int* estimation, int weight, Vec3b p) {
    estimation[0] += weight * p[0];
    estimation[1] += weight * p[1];
    estimation[2] += weight * p[2];
}

template <typename T> static inline T saturateCastFromArray(int* estimation);

template <> inline uchar saturateCastFromArray(int* estimation) {
    return saturate_cast<uchar>(estimation[0]);
}

template <> inline Vec2b saturateCastFromArray(int* estimation) {
    Vec2b res;
    res[0] = saturate_cast<uchar>(estimation[0]);
    res[1] = saturate_cast<uchar>(estimation[1]);
    return res;
}

template <> inline Vec3b saturateCastFromArray(int* estimation) {
    Vec3b res;
    res[0] = saturate_cast<uchar>(estimation[0]);
    res[1] = saturate_cast<uchar>(estimation[1]);
    res[2] = saturate_cast<uchar>(estimation[2]);
    return res;
}

#endif