// controllerlink.h - one controller for a GUI application: a RemoteClient in its own thread,
// the results as Qt signals (delivered in the thread of the ControllerLink object, normally
// the GUI thread). One ControllerLink per serial port.
//
// After open() the link detects the controller (PING, then ID), polls the keyboard leds
// (LEDS, 5 times a second) and executes the command lines given to send() one after the
// other (stop-and-wait). Link state:
//     Closed - the port is closed
//     NoLink - the port is open, the controller does not answer (detection repeated every 2 s)
//     Link   - connected
// 3 requests in a row without an answer = link lost: lost(), state NoLink, detection again.
// When the port fails (e.g. the USB adapter was unplugged) the link closes: error(), closed().
//
// Example
//     auto *link = new AdvCtrl::ControllerLink(this);
//     connect(link, &AdvCtrl::ControllerLink::stateChanged, this, &MyWidget::showLinkState);
//     connect(link, &AdvCtrl::ControllerLink::reply, this,
//             [](const QString &command, const QString &result) { qDebug() << command << result; });
//     link->open("/dev/ttyUSB0");
//     link->send("CAM 2");
//     link->send("BR 12");

#ifndef ADVCTRL_CONTROLLERLINK_H
#define ADVCTRL_CONTROLLERLINK_H

#include "remoteclient.h"

#include <QObject>
#include <QString>

namespace AdvCtrl {

class LinkThread;

class ControllerLink : public QObject
{
    Q_OBJECT

public:
    enum State { Closed, NoLink, Link };
    Q_ENUM(State)

    static constexpr int LedsPeriodMs  = 200;    // LEDS polling
    static constexpr int DetectRetryMs = 2000;   // detection retry while not detected
    static constexpr int LostAfter     = 3;      // requests in a row without an answer -> link lost

    explicit ControllerLink(QObject *parent = nullptr);
    ~ControllerLink() override;                  // stops the thread and closes the port

    State state() const;
    QString portName() const;                    // port of the running link, "" when closed

public slots:
    void open(const QString &portName, int baudRate = RemoteClient::DefaultBaudRate);
    void close();                                // closed() follows when the port is released
    void send(const QString &commandLine);       // the result comes as reply(commandLine, result)

signals:
    void stateChanged(AdvCtrl::ControllerLink::State state);
    void detected(const QString &firmware, const QString &cameras, const QString &uid);
    void notDetected();                          // a detection attempt failed (retried every 2 s)
    void lost();                                 // 3 requests in a row without an answer
    void leds(quint32 mask);                     // keyboard leds, bit order = RemoteClient::LedNames
    // result: "OK[ data]", "ERR <code> <text>" or "!! <why there is no reply>"
    void reply(const QString &commandLine, const QString &result);
    void error(const QString &message);
    void closed();

private:
    friend class LinkThread;

    void setState(State state);
    void handleDetected(const QString &firmware, const QString &cameras, const QString &uid);
    void handleNotDetected();
    void handleLost();
    void handleClosed();

    LinkThread *m_thread = nullptr;
    State m_state = Closed;
    QString m_portName;
};

} // namespace AdvCtrl

#endif // ADVCTRL_CONTROLLERLINK_H