#include <gr2/gr2.h>

#include <cstdint>
#include <cstdio>
#include <string>
#include <vector>

namespace {

void wr32(std::vector<uint8_t> &bytes, size_t off, uint32_t value) {
	bytes[off + 0] = uint8_t(value);
	bytes[off + 1] = uint8_t(value >> 8);
	bytes[off + 2] = uint8_t(value >> 16);
	bytes[off + 3] = uint8_t(value >> 24);
}

std::vector<uint8_t> granny_header(size_t size, uint32_t section_count) {
	std::vector<uint8_t> bytes(size, 0);
	const uint32_t magic[] = { 0xCAB067B8, 0x0FB16DF8, 0x7E8C7284, 0x1E00195E };
	for (int i = 0; i < 4; ++i) {
		wr32(bytes, size_t(i) * 4, magic[i]);
	}
	constexpr size_t h = 32;
	wr32(bytes, h + 0, 6); // Version
	wr32(bytes, h + 4, uint32_t(size));
	wr32(bytes, h + 12, 40); // section table starts at byte 72
	wr32(bytes, h + 16, section_count);
	// Root type/object remain section 0, offset 0. With no section this must be
	// rejected by the FileInfo stage rather than returned as an empty File.
	return bytes;
}

bool expect_failure(const std::vector<uint8_t> &bytes, const char *stage) {
	gr2::LoadError err;
	auto file = gr2::File::load(bytes.data(), bytes.size(), &err);
	if (file || err.stage != stage) {
		std::fprintf(stderr, "expected failure stage '%s', got file=%d stage='%s' message='%s'\n",
				stage, file.has_value(), err.stage.c_str(), err.message.c_str());
		return false;
	}
	return true;
}

} // namespace

int main() {
	bool ok = true;
	ok &= expect_failure(std::vector<uint8_t>(80, 0), "header");
	ok &= expect_failure(granny_header(80, 0), "fileinfo");

	auto unsupported = granny_header(160, 1);
	constexpr size_t section = 72;
	wr32(unsupported, section + 0, 4); // unsupported BitKnit
	wr32(unsupported, section + 4, uint32_t(unsupported.size()));
	wr32(unsupported, section + 12, 1); // non-empty expanded section
	ok &= expect_failure(unsupported, "section");

	auto bad_offset = granny_header(160, 1);
	wr32(bad_offset, section + 4, UINT32_MAX);
	ok &= expect_failure(bad_offset, "section");

	return ok ? 0 : 1;
}