//
//  biginteger.h
//  bigdecimal
//
//  Created by Sam Jaffe on 6/30/17.
//

#pragma once

#include <string>
#include <vector>

#include "number_format.h"

namespace math {
class biginteger {
private:
  template <typename Int>
  using is_signed_t =
      typename std::enable_if<std::numeric_limits<Int>::is_integer &&
                                  std::numeric_limits<Int>::is_signed,
                              int>::type;
  template <typename Int>
  using is_unsigned_t =
      typename std::enable_if<std::numeric_limits<Int>::is_integer &&
                                  !std::numeric_limits<Int>::is_signed,
                              int>::type;

public:
  using data_type = std::vector<int32_t>;
  static biginteger const ZERO, ONE, NEGATIVE_ONE;
  static constexpr int32_t const MAX_SEG{999999999};
  static constexpr int32_t const OVER_SEG{1000000000};
  static constexpr int32_t const SEG_DIGITS{9};

public:
  // Constructors
  biginteger();

  template <typename Int>
  biginteger(Int value, is_signed_t<Int> = 0)
      : biginteger(value < 0,
                   static_cast<uint64_t>(value < 0 ? -value : value)) {}

  template <typename Int>
  biginteger(Int value, is_unsigned_t<Int> = 0)
      : biginteger(false, static_cast<uint64_t>(value)) {}

  biginteger(char const *);
  // Unary operators
  biginteger operator-() const;
  // Binary operators
  friend biginteger operator+(biginteger, biginteger const &);
  friend biginteger operator-(biginteger, biginteger const &);
  friend biginteger operator*(biginteger, biginteger const &);
  friend biginteger operator/(biginteger, biginteger const &);
  friend biginteger operator%(biginteger, biginteger const &);
  friend biginteger & operator+=(biginteger &, biginteger const &);
  friend biginteger & operator-=(biginteger &, biginteger const &);
  friend biginteger & operator*=(biginteger &, biginteger const &);
  friend biginteger & operator/=(biginteger &, biginteger const &);
  // Output
  std::string to_string(number_format const & fmt = default_fmt) const;
  // Comparison
  friend bool operator==(biginteger const &, biginteger const &);
  friend bool operator!=(biginteger const &, biginteger const &);
  friend bool operator<=(biginteger const &, biginteger const &);
  friend bool operator<(biginteger const &, biginteger const &);
  friend bool operator>=(biginteger const &, biginteger const &);
  friend bool operator>(biginteger const &, biginteger const &);

private:
  biginteger(bool, uint64_t);
  void subtract_impl(biginteger const & lhs, bool is_sub);
  friend void swap(biginteger & rhs, biginteger & lhs) {
    using std::swap;
    swap(rhs.is_negative, lhs.is_negative);
    swap(rhs.data, lhs.data);
  }
  bool is_negative;
  data_type data{};
};
}