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

#include "ASSlice.h"

namespace ais
{

    bool Slice::operator==(const Slice &otherSlice) const noexcept
    {
        return start == otherSlice.start && stop == otherSlice.stop && step == otherSlice.step;
    }

    bool Slice::operator!=(const Slice &otherSlice) const noexcept
    {
        return !(*this == otherSlice);
    }

    std::string Slice::str() const
    {
        std::string out =
            "[" + std::to_string(start) + ":" + std::to_string(stop) + ":" + std::to_string(step) + "]\n";
        return out;
    }

    void Slice::print() const
    {
        std::cout << *this;
    }

    void Slice::make_positive_and_validate(size_t arraySize)
    {
        /// convert the start value
        if (start < 0)
        {
            start += arraySize;
        }

        if (start > (arraySize - 1))
        {
            throw std::invalid_argument("Invalid start value for array of size " + std::to_string(arraySize) +
                                        ".");
        }

        /// convert the stop value
        if (stop < 0)
        {
            stop += arraySize;
        }
        if (stop > (arraySize))
        {
            throw std::invalid_argument("Invalid stop value for array of size " + std::to_string(arraySize) +
                                        ".");
        }

        /// do some error checking
        if (start < stop)
        {
            if (step < 0)
            {
                throw std::invalid_argument("Invalid slice values [" + std::to_string(start) + ", " +
                                            std::to_string(stop) + ", " + std::to_string(step) + ']');
            }
        }

        if (stop < start)
        {
            if (step > 0)
            {
                throw std::invalid_argument("Invalid slice values [" + std::to_string(start) + ", " +
                                            std::to_string(stop) + ", " + std::to_string(step) + ']');
            }

            /// otherwise flip things around for my own sanity
            std::swap(start, stop);
            step *= -1;
        }
    }

    size_t Slice::element_number(size_t arraySize)
    {
        make_positive_and_validate(arraySize);

        size_t num = 0;
        for (size_t i = start; i < stop; i += step)
        {
            ++num;
        }
        return num;
    }

} // namespace ais