#include "quam/pack.h"

static constexpr quint32 sizeOfPackEntry = 64;

static std::pair<quint32, quint32> readPackHeader(std::istream &st) {
	auto magic = readBytes<4>(st);

	if(magic != std::array{'P', 'A', 'C', 'K'}) {
		throw FileFormatError("not a pak file (invalid magic number)");
	}

	auto dirOffset = readLE<quint32>(st);
	auto dirSize   = readLE<quint32>(st);

	if(dirSize % sizeOfPackEntry != 0) {
		throw FileFormatError("invalid directory size");
	}

	return std::make_pair(dirOffset, dirSize / sizeOfPackEntry);
}

static Arc::File readPackEntry(std::istream &st) {
	auto entName   = readBytes<56>(st);
	auto entOffset = readLE<quint32>(st);
	auto entSize   = readLE<quint32>(st);

	if(entName.front() == '/') {
		throw FileFormatError("empty root directory name");
	}

	auto pos = st.tellg();

	st.seekg(entOffset);

	QByteArray data;
	data.resize(entSize);
	st.read(data.data(), entSize);
	st.seekg(pos);

	return Arc::File{ntbsToString(entName), std::move(data)};
}

static void insertFile(Arc::Dir &dir, Arc::File &file, std::string name) {
	Option<std::string> next;

	if(auto slash = name.find('/'); slash != std::string::npos) {
		next = name.substr(slash + 1);
		name = name.substr(0, slash);
	}

	auto existing = dir.findNode(name);
	if(next) {
		Arc::Node *ref;
		if(existing) {
			ref = existing;
		} else {
			ref = new Arc::Dir(name);
			dir.emplaceBack(ref);
		}
		insertFile(*ref->getDir(), file, *next);
	} else if(!existing) {
		file.name   = name;
		file.parent = &dir;
		dir.emplaceBack(new Arc::File(std::move(file)));
	} else {
		throw FileFormatError("duplicate file");
	}
}

Arc::Dir readPack(std::istream &st) {
	auto hdr = readPackHeader(st);
	st.seekg(hdr.first);

	Arc::Dir root{std::string{}};

	for(quint32 i = 0; i < hdr.second; i++) {
		auto file = readPackEntry(st);
		insertFile(root, file, file.name);
	}

	return root;
}

PackValidator::PackValidator(QObject *parent) :
	QValidator{parent}
{
}

QValidator::State PackValidator::validate(QString &input, int &pos) const {
	return QValidator::Acceptable;
}

// EOF