/*
 * msg_client.h — C++ транспортный клиент для chat GUI
 *
 * Подключается к utun msg_transport по localhost TCP.
 * Протокол: [size:2][type:1][id:8][options:1][data...] (msg_transport.h).
 */

#ifndef MSG_CLIENT_H
#define MSG_CLIENT_H

#include <QObject>
#include <QByteArray>
#include <QTcpSocket>
#include <cstdint>

class MsgClient : public QObject {
    Q_OBJECT
public:
    explicit MsgClient(QObject* parent = nullptr);
    ~MsgClient() override;

    void connectToHost(const QString& host, quint16 port);
    void disconnectFromHost();
    bool isConnected() const;

    void bind(quint64 peerId);
    void unbind();
    bool isBound() const            { return m_boundPeerId != 0; }
    quint64 boundPeerId() const     { return m_boundPeerId; }

    void send(const QByteArray& data);
    void send(const uint8_t* data, size_t len);
    void sendSigned(const QByteArray& data);
    void sendTo(quint64 dstPeerId, const QByteArray& data);

    void requestPublicKey();
    void requestPrivateKey();
    void requestPeerInfo(quint64 peerId);

signals:
    void connected();
    void disconnected();
    void bound(quint64 peerId);
    void unbound();
    void received(quint64 peerId, const QByteArray& data);
    void errorOccurred(uint8_t code, const QString& message);
    void publicKeyReceived(const QByteArray& key);    // 32 байта X25519
    void privateKeyReceived(const QByteArray& key);   // 32 байта X25519
    void peerInfoReceived(quint64 peerId, const QByteArray& x25519Pubkey,
                          const QByteArray& ed25519Pubkey);

private:
    static constexpr size_t   kMaxMsgSize = 8192;
    static constexpr uint8_t  kCtlBind    = 0x01;
    static constexpr uint8_t  kCtlUnbind  = 0x02;
    static constexpr uint8_t  kCtlGetPubkey  = 0x03;
    static constexpr uint8_t  kCtlGetPrivkey = 0x04;
    static constexpr uint8_t  kCtlGetPeerInfo = 0x05;
    static constexpr uint8_t  kDataSend   = 0x10;
    static constexpr uint8_t  kDataRecv   = 0x11;
    static constexpr uint8_t  kRspBindOk  = 0xE1;
    static constexpr uint8_t  kRspPubkey  = 0xE2;
    static constexpr uint8_t  kRspPrivkey = 0xE3;
    static constexpr uint8_t  kRspPeerInfo = 0xE4;
    static constexpr uint8_t  kRspError   = 0xFF;
    static constexpr uint8_t  kOptSigned  = 0x01;
    static constexpr size_t   kHdrSize    = 12;

    QTcpSocket* m_socket;
    QByteArray  m_recvBuffer;
    quint64     m_boundPeerId = 0;

    void onReadyRead();
    void onSocketError(QAbstractSocket::SocketError);
    void processMessages();
    void dispatch(uint8_t type, quint64 id, const QByteArray& payload);
    QByteArray buildMessage(uint8_t type, quint64 id, uint8_t options, const QByteArray& data);
};

#endif // MSG_CLIENT_H