/*!
 *
 * Copyright (c) 2026 Diality Inc. - All Rights Reserved.
 * \copyright
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * \file    DCSSimController.h
 * \author  (original)  Stephen Quong
 * \date    (original)  30-Jul-2026
 *
 */
#pragma once

#include <QByteArray>
#include <QObject>
#include <QPointer>
#include <QSslCertificate>
#include <QSslKey>
#include <QTcpServer>
#include <QTcpSocket>

#include "MqttPacket.h"

/*!
 * \brief   QTcpServer that upgrades accepted connections to server-side TLS.
 * \details Plain QTcpServer while no TLS material is set. With material set,
 *          each accepted descriptor becomes a QSslSocket and the handshake is
 *          started before the connection is surfaced.
 */
class SslTcpServer : public QTcpServer
{
    Q_OBJECT

public:
    /*!
     * \brief   Server-side TLS material; TLS is disabled while cert is null.
     */
    struct Tls
    {
        QSslCertificate cert;              ///< Server certificate.
        QSslKey key;                       ///< Server private key.
        QList<QSslCertificate> caCerts;    ///< When set, clients must present a certificate these sign (mTLS).
    };

    using QTcpServer::QTcpServer;

    void setTls(const Tls &tls);

protected:
    void incomingConnection(qintptr socketDescriptor) override;

private:
    Tls _tls;
};

/*!
 * \brief   Diality Cloud System (DCS) simulator
 */
class DCSSimController : public QObject
{
    Q_OBJECT

public:
    /*!
     * \brief   TLS configuration, all PEM; TLS is off while certPath is empty.
     */
    struct TlsConfig
    {
        QString certPath;   ///< Server certificate.
        QString keyPath;    ///< Server private key.
        QString caPath;     ///< When set, clients must present a certificate this bundle signs (mTLS).
    };

    explicit DCSSimController(quint16 port, const TlsConfig &tls = {}, QObject *parent = nullptr);

    bool listen();

private Q_SLOTS:
    void onNewConnection();
    void onReadyRead();
    void onDisconnected();

private:
    bool initTls();
    void handlePacket(const Mqtt::Packet &packet);
    void handleConnectPacket(const Mqtt::Packet &packet);
    void handlePublishPacket(const Mqtt::Packet &packet);
    void dumpPayload(const QByteArray &payload);

    SslTcpServer _server;
    QPointer<QTcpSocket> _client;
    QByteArray _rxBuf;
    quint16 _port;
    TlsConfig _tlsConfig;
    quint64 _publishCount = 0;
};