#pragma once

#include <list>
#include <ostream>

#include <cstdint>

class number {
public:
    number() = default;
    number(const number &) = default;
    number(number &&) = default;

    number &operator=(const number &) = default;
    number &operator=(number &&) = default;

    number(std::uint64_t);

    /**
     * \brief Return a hexadecimal string representation of this number.
     */
    std::string to_hex_string() const;

    /**
     * \brief Return a decimal string representation of this number.
     */
    std::string to_dec_string() const;

    /**
     * \brief Return a 32-bits-wide integer that corresponds to this number.
     *
     * \throws std::out_of_range The number cannot be represented by a single
     * 32-bits-wide integer.
     */
    std::uint32_t to_uint32() const;

    /**
     * \brief Return a 64-bits-wide integer that corresponds to this number.
     *
     * \throws std::out_of_range The number cannot be represented by a single
     * 64-bits-wide integer.
     */
    std::uint64_t to_uint64() const;

    /**
     * \brief Return true if this number is not equal to 0. Otherwise, return
     * false.
     */
    explicit operator bool() const;

    /**
     * \brief Return the result of the addition of a number and this number.
     *
     * \param n The number to add to this number.
     */
    number operator+(const number &n) const;

    /**
     * \brief Return the result of the multiplication of a number and this
     * number.
     *
     * \param n The number to multiply with this number.
     */
    number operator*(const number &) const;

    /**
     * \brief Return a number equals to this number where n bits have been
     * shifted to the left.
     *
     * \param n Number of bits to shift.
     */
    number operator<<(std::uint32_t n) const;

    /**
     * \brief Return a number equals to this number where n bits have been
     * shifted to the right.
     *
     * \param n Number of bits to shift.
     */
    number operator>>(std::uint32_t) const;

    /**
     * \brief Tell whether the number passed as parameter is strictly less than
     * this number.
     *
     * \param n The number to compare with this number.
     */
    bool operator<(const number &n) const;

    /**
     * \brief Tell whether the number passed as parameter is strictly greater
     * than this number.
     *
     * \param n The number to compare with this number.
     */
    bool operator>(const number &n) const;

    /**
     * \brief Tell whether the number passed as parameter is less than or equal
     * to this number.
     *
     * \param n The number to compare with this number.
     */
    bool operator<=(const number &n) const;

    /**
     * \brief Tell whether the number passed as parameter is greater than or
     * equal to this number.
     *
     * \param n The number to compare with this number.
     */
    bool operator>=(const number &n) const;

    /**
     * \brief Tell whether the number passed as parameter is equal to this
     * number.
     *
     * \param n The number to compare with this number.
     */
    bool operator==(const number &n) const;

    /**
     * \brief Tell whether the number passed as parameter is not equal to this
     * number.
     *
     * \param n The number to compare with this number.
     */
    bool operator!=(const number &n) const;

    /**
     * \brief Tell whether this number evaluates to false.
     */
    bool operator!() const;

    /**
     * \brief Add a number to this number.
     *
     * \param n Number to add to this number.
     */
    number &operator+=(const number &n);

    /**
     * \brief Multiply a number with this number.
     *
     * \param n Number with multiply to this number.
     */
    number &operator*=(const number &n);

    /**
     * \brief Shift the number n bits to the left.
     *
     * \param n Number of bits to shift.
     */
    number &operator<<=(std::uint32_t);

    /**
     * \brief Shift the number n bits to the right.
     *
     * \param n Number of bits to shift.
     */
    number &operator>>=(std::uint32_t);

    /**
     * \brief Increment this number.
     */
    number &operator++();

private:
    /**
     * \brief Remove unused leading 0 operands.
     *
     * Call this method after shrinking the number so that leading 0 operands
     * are removed.
     */
    void shrink_to_fit();

     /* First item is the least significant. */
    std::list<std::uint32_t> _operands;
};

std::ostream &operator<<(std::ostream &, const number &);