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

#include <string>

#include "core/Error.h"
#include "ASMatrix.h"

namespace ais
{
    //============================================================================
    // Method Description:
    /// Append values to the end of an array.
    ///
    /// @param array
    /// @param appendValues
    /// @param axis (Optional, default NONE): The axis along which values are appended.
    /// If axis is not given, both array and appendValues
    /// are flattened before use.
    /// @return Matrix
    ///
    template <typename dtype>
    Matrix<dtype> append(const Matrix<dtype> &array, const Matrix<dtype> &appendValues, Axis axis = Axis::NONE)
    {
        switch (axis)
        {
        case Axis::NONE:
        {
            Matrix<dtype> returnArray(1, array.size() + appendValues.size());
            std::copy(std::execution::par_unseq, array.cbegin(), array.cend(), returnArray.begin());
            std::copy(std::execution::par_unseq, appendValues.cbegin(),
                      appendValues.cend(),
                      returnArray.begin() + array.size());

            return returnArray;
        }
        case Axis::ROW:
        {
            const Shape inShape = array.shape();
            const Shape appendShape = appendValues.shape();
            if (inShape.cols != appendShape.cols)
            {
                THROW_INVALID_ARGUMENT(
                    "all the input array dimensions except for the concatenation axis must match exactly");
            }

            Matrix<dtype> returnArray(inShape.rows + appendShape.rows, inShape.cols);
            std::copy(std::execution::par_unseq, array.cbegin(), array.cend(), returnArray.begin());
            std::copy(std::execution::par_unseq, appendValues.cbegin(),
                      appendValues.cend(),
                      returnArray.begin() + array.size());

            return returnArray;
        }
        case Axis::COLUMN:
        {
            const Shape inShape = array.shape();
            const Shape appendShape = appendValues.shape();
            if (inShape.rows != appendShape.rows)
            {
                THROW_INVALID_ARGUMENT(
                    "all the input array dimensions except for the concatenation axis must match exactly");
            }

            Matrix<dtype> returnArray(inShape.rows, inShape.cols + appendShape.cols);
            for (uint32_t row = 0; row < returnArray.shape().rows; ++row)
            {
                std::copy(std::execution::par_unseq, array.cbegin(row), array.cend(row), returnArray.begin(row));
                std::copy(std::execution::par_unseq, appendValues.cbegin(row),
                          appendValues.cend(row),
                          returnArray.begin(row) + inShape.cols);
            }

            return returnArray;
        }
        default:
        {
            THROW_INVALID_ARGUMENT("Unimplemented axis type.");
            return {}; // get rid of compiler warning
        }
        }
    }
} // namespace ais