/*
 *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
 *  Copyright (C) 2014 Kyle Manna <kyle@kylemanna.com>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 or (at your option)
 *  version 3 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef KEEPASSXC_YUBIKEY_H
#define KEEPASSXC_YUBIKEY_H

#include <QHash>
#include <QMultiMap>
#include <QMutex>
#include <QObject>
#include <QRecursiveMutex>
#include <QTimer>

#include <botan/secmem.h>

typedef QPair<unsigned int, int> YubiKeySlot;
Q_DECLARE_METATYPE(YubiKeySlot);

/**
 * Singleton class to manage the interface to hardware key(s)
 */
class YubiKey : public QObject
{
    Q_OBJECT

public:
    using KeyMap = QMultiMap<YubiKeySlot, QString>;

    enum class ChallengeResult : int
    {
        YCR_ERROR = 0,
        YCR_SUCCESS = 1,
        YCR_WOULDBLOCK = 2,
        YCR_KEYNOTFOUND = 3,
    };

    static YubiKey* instance();
    bool isInitialized();

    bool findValidKeys();
    void findValidKeysAsync();

    KeyMap foundKeys();
    int connectedKeys();

    ChallengeResult challenge(YubiKeySlot slot, const QByteArray& challenge, Botan::secure_vector<char>& response);
    bool testChallenge(YubiKeySlot slot, bool* wouldBlock = nullptr);

    QString errorMessage();

signals:
    /**
     * Emitted when a detection process completes. Use the `detectedSlots`
     * accessor function to get information on the available slots.
     *
     * @param found - true if a key was found
     */
    void detectComplete(bool found);

    /**
     * Emitted when user needs to interact with the hardware key to continue
     */
    void userInteractionRequest();

    /**
     * Emitted before/after a challenge-response is performed
     */
    void challengeStarted();
    void challengeCompleted();

private:
    explicit YubiKey();

    static YubiKey* m_instance;

    QTimer m_interactionTimer;
    bool m_initialized = false;
    bool m_findingKeys = false;
    QString m_error;

    // Prevents multiple simultaneous operations on hardware keys
    static QMutex s_interfaceMutex;

    KeyMap m_usbKeys;
    KeyMap m_pcscKeys;

    int m_connectedKeys = 0;

    Q_DISABLE_COPY(YubiKey)
};

#endif // KEEPASSXC_YUBIKEY_H
