/*
    Copyright (c) 2007 Volker Krause <vkrause@kde.org>

    This library is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by
    the Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    This library 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 Library General Public
    License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to the
    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.
*/

#ifndef AKONADI_CONTROL_H
#define AKONADI_CONTROL_H

#include "akonadi_export.h"
#include <QtCore/QObject>

namespace Akonadi {

/**
 * @short Provides methods to control the Akonadi server process.
 *
 * This class provides synchronous methods (ie. use a sub-eventloop)
 * to control the Akonadi service. For asynchronous methods see
 * Akonadi::ServerManager.
 *
 * The most important method in here is widgetNeedsAkonadi(). It is
 * recommended to call it with every top-level widget of your application
 * as argument, assuming your application relies on Akonadi being operational
 * of course.
 *
 * While the Akonadi server automatically started by Akonadi::Session
 * on first use, it might be necessary for some use-cases to guarantee
 * a running Akonadi service at some point. This can be done using
 * start().
 *
 * Example:
 *
 * @code
 *
 * if ( !Akonadi::Control::start() ) {
 *   qDebug() << "Unable to start Akonadi server, exit application";
 *   return 1;
 * } else {
 *   ...
 * }
 *
 * @endcode
 *
 * @author Volker Krause <vkrause@kde.org>
 *
 * @see Akonadi::ServerManager
 */
class AKONADI_EXPORT Control : public QObject
{
    Q_OBJECT

public:
    /**
     * Destroys the control object.
     */
    ~Control();

    /**
     * Starts the Akonadi server synchronously if it is not already running.
     * @return @c true if the server was started successfully or was already
     * running, @c false otherwise
     */
    static bool start();

    /**
     * Same as start(), but with GUI feedback.
     * @param parent The parent widget.
     * @since 4.2
     */
    static bool start(QWidget *parent);

    /**
     * Stops the Akonadi server synchronously if it is currently running.
     * @return @c true if the server was shutdown successfully or was
     * not running at all, @c false otherwise.
     * @since 4.2
     */
    static bool stop();

    /**
     * Same as stop(), but with GUI feedback.
     * @param parent The parent widget.
     * @since 4.2
     */
    static bool stop(QWidget *parent);

    /**
     * Restarts the Akonadi server synchronously.
     * @return @c true if the restart was successful, @c false otherwise,
     * the server state is undefined in this case.
     * @since 4.2
     */
    static bool restart();

    /**
     * Same as restart(), but with GUI feedback.
     * @param parent The parent widget.
     * @since 4.2
     */
    static bool restart(QWidget *parent);

    /**
     * Disable the given widget when Akonadi is not operational and show
     * an error overlay (given enough space). Cascading use is automatically
     * detected and resolved.
     * @param widget The widget depending on Akonadi being operational.
     * @since 4.2
     */
    static void widgetNeedsAkonadi(QWidget *widget);

protected:
    /**
     * Creates the control object.
     */
    Control();

private:
    //@cond PRIVATE
    class Private;
    Private *const d;

    Q_PRIVATE_SLOT(d, void serverStateChanged(Akonadi::ServerManager::State))
    Q_PRIVATE_SLOT(d, void createErrorOverlays())
    Q_PRIVATE_SLOT(d, void cleanup())
    //@endcond
};

}

#endif
