#include "quam/wad.h"

namespace Wad {
	enum Compression {
		CompressNone,
		CompressLZSS,
	};
}

struct WadHeader {
	quint32 dirOffset;
	quint32 dirNum;
};

struct WadEntry {
	std::string   name;
	Arc::FileType type;
	ArcFile       file;
};

static WadHeader readWadHeader(std::istream &st) {
	auto magic = readBytes<4>(st);

	if(magic != std::array{'W', 'A', 'D', '2'}) {
		throw std::runtime_error("not a wad2 file (invalid magic number)");
	}

	WadHeader hdr;
	hdr.dirOffset = readLE<quint32>(st);
	hdr.dirNum    = readLE<quint32>(st);
	return hdr;
}

static WadEntry readWadEntry(std::istream &st) {
	auto entOffset = readLE<quint32>(st);
	auto entSize   = readLE<quint32>(st);
	auto entCSize  = readLE<quint32>(st);
	auto entType   = readByte(st);
	auto entCompr  = readByte(st);
	/*   padding  */ readBytes<2>(st);
	auto entName   = readBytes<16>(st);

	if(entSize != entCSize || entCompr != Wad::CompressNone) {
		throw std::runtime_error("compressed files not implemented");
	}

	auto pos = st.tellg();

	st.seekg(entOffset);

	ArcFile file;
	file.resize(entSize);
	st.read(file.data(), entSize);

	st.seekg(pos);

	WadEntry ent;
	ent.name = ntbsToString(entName);
	ent.file = std::move(file);
	ent.type = Arc::getFileType(entType);
	return ent;
}

ArcDir readWad(std::istream &st) {
	auto hdr = readWadHeader(st);
	st.seekg(hdr.dirOffset);

	ArcDir root;

	for(quint32 i = 0; i < hdr.dirNum; i++) {
		auto ent = readWadEntry(st);
		if(root.findNode(ent.name) != root.end()) {
			throw std::runtime_error("duplicate file");
		}
		root.emplace_back(std::move(ent.file), std::move(ent.name), ent.type);
	}

	return root;
}

// EOF