/*
 *   Copyright (C) 2011 Ivan Cukic <ivan.cukic(at)kde.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License version 2,
 *   or (at your option) any later version, as published by the Free
 *   Software Foundation
 *
 *   This program 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 Lesser General Public License for more details
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef ACTIVITIES_RESOURCEINSTANCE_H
#define ACTIVITIES_RESOURCEINSTANCE_H

#include <QObject>
#include <QWidget>
#include <QUrl>

#include "kactivities_export.h"

namespace KActivities {

class ResourceInstancePrivate;

/**
 * This class is used to notify the system that a file, web page
 * or some other resource has been accessed.
 *
 * It provides methods to notify the system when the resource was
 * opened, modified and closed, along with in what window the
 * resource is shown.
 *
 * You should create an instance of this class for every resource
 * you open.
 *
 * "The system" in this case can be the backend for tracking
 * and automatically scoring files that are being accessed, the
 * system to show the open files per window in the taskbar,
 * the share-like-connect, etc.
 *
 * The user of this class shouldn't care about the backend
 * systems - everything is done under-the-hood automatically.
 *
 */
class KACTIVITIES_EXPORT ResourceInstance: public QObject
{
    Q_OBJECT

    Q_PROPERTY(QUrl uri READ uri WRITE setUri)
    Q_PROPERTY(QString mimetype READ mimetype WRITE setMimetype)
    Q_PROPERTY(QString title READ title WRITE setTitle)
    Q_PROPERTY(WId winId READ winId)
    Q_PROPERTY(AccessReason accessReason READ accessReason)

public:
    /***
     * The reason for opening the resource
     */
    enum AccessReason {
         User = 0,      ///< Due to an explicit user request
         Scheduled = 1, ///< As a result of a user-scheduled action
         Heuristic = 2, ///< Deduced from user's activity, or indirectly requested
         System = 3,    ///< Due to a system event
         World = 4      ///< Due to an action performed by an external entity
    };
    Q_ENUMS(AccessReason)

    /**
     * Creates a new resource instance
     * @param wid id of the window that will show the resource
     * @param reason reason for opening the resource
     * @param application application's name (the name used for the .desktop file).
     *        If not specified, QCoreApplication::applicationName is used
     * @param parent pointer to the parent object
     */
    explicit ResourceInstance(WId wid, AccessReason reason = User, const QString &application = QString(), QObject *parent = 0);

    /**
     * Creates a new resource instance and automatically
     * notifies the system that it was opened.
     *
     * In some special cases, where the URI of the resource is
     * being constantly changed (for example, in the world globe,
     * street map applications) you have two options:
     *  - to pass an empty resourceUri while passing the mimetype
     *  - to update the uri from time to time (in the example of
     *    the world map - to send URIs for major objects - cities
     *    or main streets.
     * and in both cases reimplementing the currentUri() method
     * which will return the exact URI shown at that specific moment.
     *
     * @param wid window id in which the resource is shown
     * @param resourceUri URI of the resource that is shown
     * @param mimetype the mime type of the resource
     * @param title the title of the resource
     * @param reason reason for opening the resource
     * @param application application's name (the name used for the .desktop file).
     *        If not specified, QCoreApplication::applicationName is used
     * @param parent pointer to the parent object
     */
    ResourceInstance(WId wid, QUrl resourceUri, const QString &mimetype = QString(), const QString &title = QString(), AccessReason reason = User, const QString &application = QString(), QObject *parent = 0);

    /**
     * Destroys the ResourceInstance and notifies the system
     * that the resource has been closed
     */
    ~ResourceInstance();

public Q_SLOTS:
    /**
     * Call this method to notify the system that you modified
     * (the contents of) the resource
     */
    void notifyModified();

    /**
     * Call this method to notify the system that the resource
     * has the focus in your application
     * @note You only need to call this in MDI applications
     */
    void notifyFocusedIn();

    /**
     * Call this method to notify the system that the resource
     * lost the focus in your application
     * @note You only need to call this in MDI applications
     */
    void notifyFocusedOut();

    /**
     * This is a convenience method that sets the new URI.
     * This is usually handled by sending the close event for
     * the previous URI, and an open event for the new one.
     */
    void setUri(const QUrl &newUri);

    /**
     * Sets the mimetype for this resource
     */
    void setMimetype(const QString &mimetype);

    /**
     * Sets the title for this resource
     */
    void setTitle(const QString &title);

Q_SIGNALS:
    /**
     * Emitted when the system wants to show the resource
     * represented by this ResourceInstance.
     *
     * You should listen to this signal if you have multiple
     * resources shown in one window (MDI). On catching it, show
     * the resource and give it focus.
     */
    void requestsFocus();

public:
    /**
     * @returns the current uri
     * The default implementation returns the URI that was passed
     * to the constructor.
     * You need to reimplement it only for the applications with
     * frequently updated URIs.
     */
    virtual QUrl uri() const;

    /**
     * @returns mimetype of the resource
     */
    QString mimetype() const;

    /**
     * @returns title of the resource
     */
    QString title() const;

    /**
     * @returns the window id
     */
    WId winId() const;

    /**
     * @returns the reason for accessing the resource
     */
    AccessReason accessReason() const;

    /**
     * If there's no way to tell for how long an application is keeping
     * the resource open, you can just call this static method - it
     * will notify the system that the application has accessed the
     * resource
     * @param uri URI of the resource
     * @param application application's name (the name used for the .desktop file).
     *        If not specified, QCoreApplication::applicationName is used
     *
     */
    static void  notifyAccessed(const QUrl &uri, const QString &application = QString());

private:
    ResourceInstancePrivate * const d;
};

}

#endif // ACTIVITIES_RESOURCEINSTANCE_H

