/*------------------------------------------------------------------------------
 *	Copyright (c) 2023 by Bai Bing (seread@163.com)
 *	S++ COPYING file for copying and redistribution conditions.
 *
 *  Alians IT Studio.
 *----------------------------------------------------------------------------*/
#pragma once

#include "ASMatrix.h"

namespace ais
{
    //============================================================================
    // Method Description:
    /// Reverse the order of elements in an array along the given axis.
    ///
    /// @param array
    /// @param axis
    /// @return Matrix
    ///
    template <typename dtype>
    Matrix<dtype> flip(const Matrix<dtype> &array, Axis axis = Axis::NONE)
    {
        switch (axis)
        {
        case Axis::NONE:
        {
            Matrix<dtype> returnArray(array);
            std::reverse(std::execution::par_unseq, returnArray.begin(), returnArray.end());
            return returnArray;
        }
        case Axis::COLUMN:
        {
            Matrix<dtype> returnArray(array);
            for (uint32_t row = 0; row < array.shape().rows; ++row)
            {
                std::reverse(std::execution::par_unseq, returnArray.begin(row), returnArray.end(row));
            }
            return returnArray;
        }
        case Axis::ROW:
        {
            return flip(array.transpose(), Axis::COLUMN).transpose();
        }
        default:
        {
            THROW_INVALID_ARGUMENT("Unimplemented axis type.");
            return {}; // get rid of compiler warning
        }
        }
    }

    //============================================================================
    // Method Description:
    /// Flip array in the left/right direction.
    ///
    /// @param array
    /// @return Matrix
    ///
    template <typename dtype>
    Matrix<dtype> fliplr(const Matrix<dtype> &array)
    {
        return flip(array, Axis::COLUMN);
    }

    //============================================================================
    // Method Description:
    /// Flip array in the up/down direction.
    ///
    /// @param array
    /// @return Matrix
    ///
    template <typename dtype>
    Matrix<dtype> flipud(const Matrix<dtype> &array)
    {
        return flip(array, Axis::ROW);
    }
} // namespace ais