#pragma once
#include <cstdint>
#include <string>
#include <istream>
#include <functional>

struct GameUUID {
	uint64_t hi = 0;
	uint64_t lo = 0;

	bool isValid() const { return hi != 0 || lo != 0; }

	// String conversion
	std::string toDashed() const;
	std::string toUndashed() const;
	std::wstring toWDashed() const;
	static GameUUID fromDashed(const std::string& s);
	static GameUUID fromUndashed(const std::string& s);

	// Generation
	static GameUUID generateV4();
	static GameUUID generateOffline(const std::string& playerName);

	// Comparison
	bool operator==(const GameUUID& o) const { return hi == o.hi && lo == o.lo; }
	bool operator!=(const GameUUID& o) const { return !(*this == o); }
	bool operator<(const GameUUID& o) const { return hi < o.hi || (hi == o.hi && lo < o.lo); }

	// Hash support for unordered containers
	struct Hash {
		size_t operator()(const GameUUID& u) const {
			size_t h = std::hash<uint64_t>{}(u.hi);
			h ^= std::hash<uint64_t>{}(u.lo) + 0x9e3779b9 + (h << 6) + (h >> 2);
			return h;
		}
	};
};

inline const GameUUID INVALID_UUID = {};

// Stream extraction for _fromString<PlayerUID> compatibility
inline std::wistream& operator>>(std::wistream& is, GameUUID& uuid)
{
	std::wstring ws;
	is >> ws;
	std::string s(ws.begin(), ws.end());
	uuid = GameUUID::fromDashed(s);
	return is;
}

// Specialise std::hash so unordered_map<PlayerUID, ...> works without explicit Hash argument
namespace std {
	template<> struct hash<GameUUID> {
		size_t operator()(const GameUUID& u) const {
			return GameUUID::Hash{}(u);
		}
	};
}