#include "catch.hpp"

#include "FileOperations.hh"

#include "LocalFile.hh"

#include "MappedFile.hh"

#include "scope_exit.hh"

#include <algorithm>

#include <array>

#include <span>

using namespace openmsx;

TEST_CASE("MappedFile preserves the local file position")

{

	std::string filename;

	auto temporary = FileOperations::openUniqueFile(FileOperations::getTempDir(), filename);

	REQUIRE(temporary);

	temporary.reset();

	scope_exit cleanup([&] { FileOperations::unlink(filename); });

	LocalFile file(filename, File::OpenMode::TRUNCATE);

	const std::array<uint8_t, 5> content = {0x12, 0x34, 0x56, 0x78, 0x9a};

	file.write(content);

	file.flush();

	for (size_t position : {size_t(0), size_t(2), content.size()}) {

		for (size_t extra : {size_t(0), size_t(3)}) {

			CAPTURE(position, extra);

			file.seek(position);

			// A file-pool hash calculation followed by ROM loading maps

			// the same file twice. Neither mapping may consume the file.

			for (int repeat = 0; repeat < 2; ++repeat) {

				CAPTURE(repeat);

				MappedFile<const uint8_t> mapped = file.mmap(extra, true);

				CHECK(file.getPos() == position);

				REQUIRE(mapped.size() == content.size() + extra);

				CHECK(std::ranges::equal(content, std::span(mapped.data(), content.size())));

				CHECK(std::all_of(mapped.begin() + content.size(), mapped.end(),

				                 [](uint8_t value) { return value == 0; }));

			}

		}

	}

}