/*
 * Copyright (c) 2018-2020 Arm Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include "SliceOperations.h"

#include "arm_compute/core/utils/helpers/tensor_transform.h"
#include "arm_compute/core/utils/misc/ShapeCalculator.h"

namespace arm_compute
{
namespace test
{
namespace validation
{
namespace reference
{
template <typename T>
SimpleTensor<T> slice(const SimpleTensor<T> &src, Coordinates starts, Coordinates ends)
{
    using namespace arm_compute::helpers::tensor_transform;

    // Validation checks
    ARM_COMPUTE_ERROR_ON(src.shape().num_dimensions() > 4);
    ARM_COMPUTE_ERROR_ON(starts.num_dimensions() > src.shape().num_dimensions());
    ARM_COMPUTE_ERROR_ON(std::any_of(starts.cbegin(), starts.cbegin() + starts.num_dimensions(), [](int i)
    {
        return i < 0;
    }));
    ARM_COMPUTE_ERROR_ON(ends.num_dimensions() > src.shape().num_dimensions());

    // Get source shape
    const TensorShape &src_shape = src.shape();

    // Get destination shape
    TensorShape dst_shape = arm_compute::misc::shape_calculator::compute_slice_shape(src_shape, starts, ends);

    // Create destination tensor
    SimpleTensor<T> dst{ dst_shape, src.data_type(), 1 };

    // Perform slice
    Window win;
    win.use_tensor_dimensions(dst_shape);
    execute_window_loop(win, [&](const Coordinates & id)
    {
        Coordinates offset;
        for(unsigned int i = 0; i < id.num_dimensions(); ++i)
        {
            offset.set(i, starts[i] + id[i]);
        }
        *reinterpret_cast<T *>(dst(id)) = *reinterpret_cast<const T *>(src(offset));
    });

    return dst;
}

template SimpleTensor<float> slice(const SimpleTensor<float> &src, Coordinates starts, Coordinates ends);
template SimpleTensor<half_float::half> slice(const SimpleTensor<half_float::half> &src, Coordinates starts, Coordinates ends);

template <typename T>
SimpleTensor<T> strided_slice(const SimpleTensor<T> &src,
                              Coordinates starts, Coordinates ends, BiStrides strides,
                              int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask)
{
    using namespace arm_compute::helpers::tensor_transform;

    // Validation checks
    ARM_COMPUTE_ERROR_ON(src.shape().num_dimensions() > 4);
    ARM_COMPUTE_ERROR_ON(starts.num_dimensions() > src.shape().num_dimensions());
    ARM_COMPUTE_ERROR_ON(ends.num_dimensions() > src.shape().num_dimensions());
    ARM_COMPUTE_ERROR_ON(strides.num_dimensions() > src.shape().num_dimensions());
    ARM_COMPUTE_ERROR_ON(std::any_of(strides.cbegin(), strides.cbegin() + strides.num_dimensions(), [](int i)
    {
        return i == 0;
    }));

    // Get source shape
    const TensorShape &src_shape = src.shape();

    // Get destination shape
    const TensorShape dst_shape = compute_strided_slice_output_shape(src_shape, starts, ends, strides, begin_mask, end_mask, shrink_axis_mask);

    // Create destination tensor
    SimpleTensor<T> dst{ dst_shape, src.data_type(), 1 };

    // Get coordinates
    Coordinates starts_abs{};
    Coordinates ends_abs{};
    Coordinates final_strides{};
    std::tie(starts_abs, ends_abs, final_strides) = calculate_strided_slice_coords(src_shape,
                                                                                   starts, ends, strides,
                                                                                   begin_mask, end_mask, shrink_axis_mask);

    // Perform strided slice
    unsigned int idx = 0;
    Window       win;
    win.use_tensor_dimensions(compute_strided_slice_output_shape(src_shape,
                                                                 starts, ends, strides,
                                                                 begin_mask, end_mask, shrink_axis_mask, true));
    execute_window_loop(win, [&](const Coordinates & id)
    {
        Coordinates offset;
        for(unsigned int i = 0; i < id.num_dimensions(); ++i)
        {
            offset.set(i, starts_abs[i] + id[i] * final_strides[i]);
        }
        dst.data()[idx++] = *reinterpret_cast<const T *>(src(offset));
    });

    return dst;
}

template SimpleTensor<float> strided_slice(const SimpleTensor<float> &src,
                                           Coordinates starts, Coordinates ends, BiStrides strides,
                                           int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask);
template SimpleTensor<half_float::half> strided_slice(const SimpleTensor<half_float::half> &src,
                                                      Coordinates starts, Coordinates ends, BiStrides strides,
                                                      int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask);
} // namespace reference
} // namespace validation
} // namespace test
} // namespace arm_compute
