#include <pslang/jit/executable.hpp>

#include <stdexcept>
#include <system_error>

#ifdef __linux__
#include <sys/mman.h>
#endif

#ifdef __APPLE__
#include <sys/mman.h>
#endif

namespace pslang::jit
{

	std::shared_ptr<std::uint8_t> make_host_executable(binary_storage const & storage)
	{
#if defined(__linux__) || defined(__APPLE__)
		auto const page_size = native_page_size();

		for (auto const & range : storage.data)
		{
			if ((range.begin % page_size) != 0)
				throw std::runtime_error("Data range start is not aligned to page boundary");

			if ((range.end % page_size) != 0)
				throw std::runtime_error("Data range end is not aligned to page boundary");
		}

		for (auto const & range : storage.code)
		{
			if ((range.begin % page_size) != 0)
				throw std::runtime_error("Code range start is not aligned to page boundary");

			if ((range.end % page_size) != 0)
				throw std::runtime_error("Code range end is not aligned to page boundary");
		}

		auto total_size = storage.storage.size();
		auto ptr = (std::uint8_t *)mmap(nullptr, total_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
		if (ptr == MAP_FAILED)
			throw std::system_error(errno, std::generic_category());

		std::copy(storage.storage.begin(), storage.storage.end(), ptr);

		for (auto const & range : storage.code)
			if (mprotect(ptr + range.begin, range.end - range.begin, PROT_READ | PROT_EXEC) != 0)
				throw std::system_error(errno, std::generic_category());

		return std::shared_ptr<std::uint8_t>(ptr, [total_size](void * ptr){ munmap(ptr, total_size); });
#else
		throw std::runtime_error("Host-executable modules are not supported for this platform");
#endif
	}

}