#include <istream>
#include <memory>

enum GameResult { Win, Tie, Loss };

class Hand {
  public:
	// Converts a user-inputted character to the correct instance of Hand.
	static std::unique_ptr<Hand> fromChar(char);
    // Randomly returns one of the variants of Hand.
    static std::unique_ptr<Hand> generateRandom();

	// Returns the lowercase name of this type of hand, for example "rock" or
	// "scissors".
	virtual std::string getHandName() const = 0;
	// Returns if this instance of Hand wins against another instance. The
	// returned value is from the perspective of this instance of hand. For
	// example, if GameResult::Win is returned, the instance of Hand wins
	// against the passed argument Hand.
	virtual GameResult compareAgainst(const Hand&) = 0;
};

class Rock : public Hand {
  public:
	std::string getHandName() const override;
	GameResult compareAgainst(const Hand&) override;
};

class Paper : public Hand {
  public:
	std::string getHandName() const override;
	GameResult compareAgainst(const Hand&) override;
};

class Scissors : public Hand {
  public:
	std::string getHandName() const override;
	GameResult compareAgainst(const Hand&) override;
};