static_assert( __cplusplus > 2023'00 );

#include "fastRandom.h"

#include <random>

#include <boost/random/taus88.hpp>

namespace Alepha::Hydrogen  ::detail::  fastRandom_m
{
	namespace
	{
		struct FastRandomState
		{
			boost::random::taus88 fastRandomState{ std::random_device{}() };
			std::uint32_t pool;
			int remainingBits= 0;

			void
			next()
			{
				pool= fastRandomState();
				remainingBits= 32;
			}

			void
			refresh()
			{
				if( remainingBits == 0 ) next();
			}

			std::uint32_t
			getBit()
			{
				refresh();
				const std::uint32_t rv= pool & 1;
				--remainingBits;
				pool>>= 1;
				return rv;
			}

			std::uint32_t
			get( int count )
			{
				std::uint32_t rv= 0;
				while( count-- )
				{
					rv<<= 1;
					rv|= getBit();
				}
				return rv;
			}
		};

		thread_local FastRandomState fastRandom;
	}

	std::uint32_t
	exports::fastRandomBits( const int numBits )
	{
		return fastRandom.get( numBits );
	}
}