/**
  * @RDE_HEADER@
  * VdControl
  * $Id$
  * $HeadURL$
  * $Author$
  * Created by Astrid Müller, SGAS, 2018-02-22
  */

#pragma once

#include "ivd_command_done_observer.h"
#include "avm_export.h"
#include "ava_types.h"
#include "avs_command_queue.h"
#include "logger.h"
#include <LtsUtilsCore/connection.h>
#include <QString>
#include <QVector>
#include <QTimer>
#include <QObject>
#include <chrono>

class QStringList;

namespace AudioVideoManagement
{

class IVdComm;


/**
 * AvaControl sits ontop of AvaComm.
 * For the communication with the AVS that must be exactly one AvaComm
 * and one AvaControl instance.
 * AvaControl uses a command queue and ensures that each command is sent after
 * the previous command finished.
 * The definition of when a command is finished is defined by the command itself.
 * Most of the commands are SimpleCommands which only wait for the OK-response.
 *
 * For those commands that have a data-response -- such as getStreamList --
 * a signal is provided that will be emitted when the command finished.
 *
 * Commands being sent while no connection is established will be dropped.
 * When the connection gets lost, all Commands still in the queue will be dropped.
 * When a command fails, all remaining commands will be dropped and the connection
 * to the AVS will be closed and established again.
 *
 * A command must complete within a defined time frame. If it does not,
 * the command is conside red failed with the implications described above.
 *
 * There are two ways to get responses that contain data -- such as the result of
 * getStreamList or queryTimeline:
 * 1. Connect to the corresponding signals in the usual way. The problem with this
 *    approach arises when there are several clients using the AvaControl-instance
 *    at the same time. Then you receive all responses no matter who
 *    initiated the corresponding command.
 * 2. You can specify an optional slot when issuing the command.
 *    This slot will be called when the command is finished. This way you only receive
 *    responses that correspond to the command you initiated.
 *
 * @see VdComm
 * @see VdSession
 * @see ICommand
 * @author Astrid Müller, Christian Fröbel
 */
class AVM_COMMON_EXPORT VdControl : public QObject, public IVdCommandDoneObserver
{
  Q_OBJECT

public:
  VdControl(IVdComm *comm, std::chrono::milliseconds commandTimeout);

  void switchContext(int exerciseId);


  /** SCRIPT */
  ///@{
  template<class Target, class Slot>
  void vdSetScript(const QString &scriptName, AvaStreamType typ, int fileSplitting, const QVector<AvaScriptEntry> &streams,
                   const QString &exportedDirBaseName, const QString &absolutePath, Target *target, Slot Target:: *slot);
  void vdSetScript(const QString &scriptName, AvaStreamType typ, int fileSplitting, const QVector<AvaScriptEntry> &streams,
                   const QString &exportedDirBaseName, const QString &absolutePath);
  void vdReleaseScript(const QString &scriptName);
  ///@}

  void keepAlive();

  /**
   * These overloaded done() methods will be called by the specific
   * commands themselves upon completion.
   */
  ///@{
  void done(ICommand *cmd) override;
  void done(AvaCommands::VdSetScript *cmd) override;

  /**
   * Called whenever a command fails due error response or other unexpected responses.
   * All queued commands will be dropped and the connection to AVS will
   * be disconnected and re-established.
   */
  void failed(ICommand *cmd) override;

  void alive(ICommand *cmd) override;
  ///@}

  /** Access to the underlying VdComm-instance. */
  IVdComm *comm() { return m_comm; }

signals:
  void vdScriptFinished(const QString &dir, AvaStreamType streamType, bool success);

  /**
   * Signalled whenever the command queue is empty again. This can have several reasons:
   * - The last command finished successfully.
   * - A command failed and the command queue was flushed.
   * - This instance is deleted with a non-empty command queue which gets flushed then.
   */
  void commandQueueEmpty();

private slots:
  void onConnected();
  void onDisconnected();
  void onTimeout();

private:
  void vdSetScript(const QString &scriptName, AvaStreamType typ, int fileSplitting, const QVector<AvaScriptEntry> &streams,
                   const QString &exportedDirBaseName, const QString &absolutePath, LtsUtils::IConnection *connection);

  void queue(ICommand *cmd, LtsUtils::IConnection *connection = nullptr);

  IVdComm           *m_comm;
  bool               m_connected{false};
  AvsCommandQueue    m_queue;
  LOGGER_T           m_logger;
};

template<class Target, class Slot>
void VdControl::vdSetScript(const QString &scriptName, AvaStreamType typ, int fileSplitting, const QVector<AvaScriptEntry> &streams, const QString &exportedDirBaseName, const QString &absolutePath, Target *target, Slot Target::*slot)
{
  vdSetScript(scriptName, typ, fileSplitting, streams, exportedDirBaseName, absolutePath,
              LtsUtils::createConnection(this, &VdControl::vdScriptFinished, target, slot));
}

} // namespace AudioVideoManagement