#include <random>
#include "random.h"

using namespace std;

static mt19937_64 rng;
// XXX: could substitute a cryptographic RNG

void random_seed(bigint seed)
{
  rng.seed(seed);
}

static uniform_int_distribution<short> choose_bit(0,1);

bool random_bool(void)
{
  return choose_bit(rng);
}

static uniform_int_distribution<int> choose_int(
  numeric_limits<int>::min(),
  numeric_limits<int>::max()
);

int random_int(void)
{
  return choose_int(rng);
}

static uniform_int_distribution<unsigned int> choose_uint(
  numeric_limits<unsigned int>::min(),
  numeric_limits<unsigned int>::max()
);

unsigned int random_uint(void)
{
  return choose_uint(rng);
}

static uniform_int_distribution<long> choose_long(
  numeric_limits<long>::min(),
  numeric_limits<long>::max()
);

long random_long(void)
{
  return choose_long(rng);
}

static uniform_int_distribution<unsigned long> choose_ulong(
  numeric_limits<unsigned long>::min(),
  numeric_limits<unsigned long>::max()
);

unsigned long random_ulong(void)
{
  return choose_ulong(rng);
}

static uniform_int_distribution<long long> choose_longlong(
  numeric_limits<long long>::min(),
  numeric_limits<long long>::max()
);

long long random_longlong(void)
{
  return choose_longlong(rng);
}

static uniform_int_distribution<unsigned long long> choose_ulonglong(
  numeric_limits<unsigned long long>::min(),
  numeric_limits<unsigned long long>::max()
);

unsigned long long random_ulonglong(void)
{
  return choose_ulonglong(rng);
}

bigint random_bigint_below(const bigint &m)
{
  // XXX: handle larger ranges
  bigint result = random_longlong();
  return result%m;
}