#include <boost/archive/iterators/binary_from_base64.hpp>
#include <boost/archive/iterators/base64_from_binary.hpp>
#include <boost/archive/iterators/transform_width.hpp>
#include <openssl/rand.h>

#include "utils.h"

std::string utils::to_base64(const std::vector<unsigned char>& binary)
{
	using namespace boost::archive::iterators;
	using It = base64_from_binary<transform_width<std::vector<unsigned char>::const_iterator, 6, 8>>;
	auto base64 = std::string(It(binary.begin()), It(binary.end()));
	// Add padding.
	return base64.append((3 - binary.size() % 3) % 3, '=');
}

std::vector<unsigned char> utils::from_base64(const std::string& base64)
{
	using namespace boost::archive::iterators;
	using It = transform_width<binary_from_base64<std::string::const_iterator>, 8, 6>;
	auto binary = std::vector<unsigned char>(It(base64.begin()), It(base64.end()));
	// Remove padding.
	auto length = base64.size();
	if(binary.size() > 2 && base64[length - 1] == '=' && base64[length - 2] == '=')
	{
		binary.erase(binary.end() - 2, binary.end());
	}
	else if(binary.size() > 1 && base64[length - 1] == '=')
	{
		binary.erase(binary.end() - 1, binary.end());
	}
	return binary;
}

std::vector<unsigned char> utils::generate_random(const size_t size){
	std::vector<unsigned char> res(size);
	if(!RAND_bytes(res.data(), size)){
		throw std::exception();
	}
	return res;
}