/*******************************************************
 * Copyright (c) 2015, ArrayFire
 * All rights reserved.
 *
 * This file is distributed under 3-clause BSD license.
 * The complete license agreement can be obtained at:
 * http://arrayfire.com/licenses/BSD-3-Clause
 ********************************************************/

#include <af/dim4.hpp>
#include <Array.hpp>
#include <err_cuda.hpp>
#include <arith.hpp>
#include <kernel/homography.hpp>
#include <algorithm>

#include <cfloat>

using af::dim4;

namespace cuda
{

#define RANSACConfidence 0.99f
#define LMEDSConfidence 0.99f
#define LMEDSOutlierRatio 0.4f

template<typename T>
int homography(Array<T> &bestH,
               const Array<float> &x_src,
               const Array<float> &y_src,
               const Array<float> &x_dst,
               const Array<float> &y_dst,
               const Array<float> &initial,
               const af_homography_type htype,
               const float inlier_thr,
               const unsigned iterations)
{
    const af::dim4 idims = x_src.dims();
    const unsigned nsamples = idims[0];

    unsigned iter = iterations;
    Array<float> err = *initArray<float>();
    if (htype == AF_HOMOGRAPHY_LMEDS) {
        iter = ::std::min(iter, (unsigned)(log(1.f - LMEDSConfidence) / log(1.f - pow(1.f - LMEDSOutlierRatio, 4.f))));
        err = createValueArray<float>(af::dim4(nsamples, iter), FLT_MAX);
    }

    af::dim4 rdims(4, iter);
    Array<float> fctr = createValueArray<float>(rdims, (float)nsamples);
    Array<float> rnd = arithOp<float, af_mul_t>(initial, fctr, rdims);

    Array<T> tmpH = createValueArray<T>(af::dim4(9, iter), (T)0);

    return kernel::computeH<T>(bestH, tmpH, err,
                               x_src, y_src, x_dst, y_dst,
                               rnd, iter, nsamples, inlier_thr, htype);
}

#define INSTANTIATE(T)                                                                  \
    template int homography<T>(Array<T> &H,                                             \
                               const Array<float> &x_src, const Array<float> &y_src,    \
                               const Array<float> &x_dst, const Array<float> &y_dst,    \
                               const Array<float> &initial,                             \
                               const af_homography_type htype, const float inlier_thr,  \
                               const unsigned iterations);

INSTANTIATE(float )
INSTANTIATE(double)

}
