/****************************************************************************
**
** Copyright (C) 2002-2003 Tim Jansen <tim@tjansen.de>
** Copyright (C) 2007-2008 Urs Wolfer <uwolfer @ kde.org>
**
** This file is part of KDE.
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; see the file COPYING. If not, write to
** the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
** Boston, MA 02110-1301, USA.
**
****************************************************************************/

#ifndef REMOTEVIEW_H
#define REMOTEVIEW_H

#ifdef QTONLY
    #include <QUrl>
    #define KUrl QUrl
    #define KRDCCORE_EXPORT
#else
    #include <KUrl>
    #include <KWallet/Wallet>
    #include <krdc_export.h>
#endif

#include <QWidget>

class HostPreferences;

/**
 * Generic widget that displays a remote framebuffer.
 * Implement this if you want to add another backend.
 *
 * Things to take care of:
 * @li The RemoteView is responsible for its size. In
 *     non-scaling mode, set the fixed size of the widget
 *     to the remote resolution. In scaling mode, set the
 *     maximum size to the remote size and minimum size to the
 *     smallest resolution that your scaler can handle.
 * @li if you override mouseMoveEvent()
 *     you must ignore the QEvent, because the KRDC widget will
 *     need it for stuff like toolbar auto-hide and bump
 *     scrolling. If you use x11Event(), make sure that
 *     MotionNotify events will be forwarded.
 *
 */
class KRDCCORE_EXPORT RemoteView : public QWidget
{
    Q_OBJECT

public:

    Q_ENUMS(Quality)

    enum Quality {
        Unknown,
        High,
        Medium,
        Low
    };

    /**
    * Describes the state of a local cursor, if there is such a concept in the backend.
    * With local cursors, there are two cursors: the cursor on the local machine (client),
    * and the cursor on the remote machine (server). Because there is usually some lag,
    * some backends show both cursors simultanously. In the VNC backend the local cursor
    * is a dot and the remote cursor is the 'real' cursor, usually an arrow.
    */

    Q_ENUMS(DotCursorState)

    enum DotCursorState {
        CursorOn,  ///< Always show local cursor (and the remote one).
        CursorOff, ///< Never show local cursor, only the remote one.
        /// Try to measure the lag and enable the local cursor if the latency is too high.
        CursorAuto
    };

    /**
    * State of the connection. The state of the connection is returned
    * by @ref RemoteView::status().
    *
    * Not every state transition is allowed. You are only allowed to transition
    * a state to the following state, with three exceptions:
    * @li You can move from every state directly to Disconnected
    * @li You can move from every state except Disconnected to
    *     Disconnecting
    * @li You can move from Disconnected to Connecting
    *
    * @ref RemoteView::setStatus() will follow this rules for you.
    * (If you add/remove a state here, you must adapt it)
    */

    Q_ENUMS(RemoteStatus)

    enum RemoteStatus {
        Connecting     = 0,
        Authenticating = 1,
        Preparing      = 2,
        Connected      = 3,
        Disconnecting  = -1,
        Disconnected   = -2
    };

    Q_ENUMS(ErrorCode)

    enum ErrorCode {
        None = 0,
        Internal,
        Connection,
        Protocol,
        IO,
        Name,
        NoServer,
        ServerBlocked,
        Authentication
    };

    virtual ~RemoteView();

    /**
     * Checks whether the backend supports scaling. The
     * default implementation returns false.
     * @return true if scaling is supported
     * @see scaling()
     */
    virtual bool supportsScaling() const;

    /**
     * Checks whether the widget is in scale mode. The
     * default implementation always returns false.
     * @return true if scaling is activated. Must always be
     *         false if @ref supportsScaling() returns false
     * @see supportsScaling()
     */
    virtual bool scaling() const;

    /**
     * Checks whether the backend supports the concept of local cursors. The
     * default implementation returns false.
     * @return true if local cursors are supported/known
     * @see DotCursorState
     * @see showDotCursor()
     * @see dotCursorState()
     */
    virtual bool supportsLocalCursor() const;

    /**
     * Sets the state of the dot cursor, if supported by the backend.
     * The default implementation does nothing.
     * @param state the new state (CursorOn, CursorOff or
     *        CursorAuto)
     * @see dotCursorState()
     * @see supportsLocalCursor()
     */
    virtual void showDotCursor(DotCursorState state);

    /**
     * Returns the state of the local cursor. The default implementation returns
     * always CursorOff.
     * @return true if local cursors are supported/known
     * @see showDotCursor()
     * @see supportsLocalCursor()
     */
    virtual DotCursorState dotCursorState() const;

    /**
     * Checks whether the view is in view-only mode. This means
     * that all input is ignored.
     */
    virtual bool viewOnly();

    /**
     * Checks whether grabbing all possible keys is enabled.
     */
    virtual bool grabAllKeys();

    /**
     * Returns the resolution of the remote framebuffer.
     * It should return a null @ref QSize when the size
     * is not known.
     * The backend must also emit a @ref framebufferSizeChanged()
     * when the size of the framebuffer becomes available
     * for the first time or the size changed.
     * @return the remote framebuffer size, a null QSize
     *         if unknown
     */
    virtual QSize framebufferSize();

    /**
     * Initiate the disconnection. This doesn't need to happen
     * immediately. The call must not block.
     * @see isQuitting()
     */
    virtual void startQuitting();

    /**
     * Checks whether the view is currently quitting.
     * @return true if it is quitting
     * @see startQuitting()
     * @see setStatus()
     */
    virtual bool isQuitting();

    /**
     * @return the host the view is connected to
     */
    virtual QString host();

    /**
     * @return the port the view is connected to
     */
    virtual int port();

    /**
     * Initialize the view (for example by showing configuration
     * dialogs to the user) and start connecting. Should not block
     * without running the event loop (so displaying a dialog is ok).
     * When the view starts connecting the application must call
     * @ref setStatus() with the status Connecting.
     * @return true if successful (so far), false
     *         otherwise
     * @see connected()
     * @see disconnected()
     * @see disconnectedError()
     * @see statusChanged()
     */
    virtual bool start() = 0;
    
    /**
     * Called when the configuration is changed.
     * The default implementation does nothing.
     */
    virtual void updateConfiguration();
    
    /**
     * @return screenshot of the view
     */
    virtual QPixmap takeScreenshot();
    
#ifndef QTONLY
    /**
     * Returns the current host preferences of this view.
     */
    virtual HostPreferences* hostPreferences() = 0;
#endif
    
    /**
     * Returns the current status of the connection.
     * @return the status of the connection
     * @see setStatus()
     */
    RemoteStatus status();

    /**
     * @return the current url
     */
    KUrl url();

public slots:
    /**
     * Called to enable or disable scaling.
     * Ignored if @ref supportsScaling() is false.
     * The default implementation does nothing.
     * @param s true to enable, false to disable.
     * @see supportsScaling()
     * @see scaling()
     */
    virtual void enableScaling(bool scale);

    /**
     * Enables/disables the view-only mode.
     * Ignored if @ref supportsScaling() is false.
     * The default implementation does nothing.
     * @param viewOnly true to enable, false to disable.
     * @see supportsScaling()
     * @see viewOnly()
     */
    virtual void setViewOnly(bool viewOnly);

    /**
     * Enables/disables grabbing all possible keys.
     * @param grabAllKeys true to enable, false to disable.
     * Default is false.
     * @see grabAllKeys()
     */
    virtual void setGrabAllKeys(bool grabAllKeys);

    /**
     * Called to let the backend know it when
     * we switch from/to fullscreen.
     * @param on true when switching to fullscreen,
     *           false when switching from fullscreen.
     */
    virtual void switchFullscreen(bool on);

    /**
     * Sends a QKeyEvent to the remote server.
     * @param event the key to send
     */
    virtual void keyEvent(QKeyEvent *event);

    /**
     * Called when the visible place changed so remote
     * view can resize itself.
     */
    virtual void scaleResize(int w, int h);

signals:
    /**
     * Emitted when the size of the remote screen changes. Also
     * called when the size is known for the first time.
     * @param x the width of the screen
     * @param y the height of the screen
     */
    void framebufferSizeChanged(int w, int h);

    /**
     * Emitted when the view connected successfully.
     */
    void connected();

    /**
     * Emitted when the view disconnected without error.
     */
    void disconnected();

    /**
     * Emitted when the view disconnected with error.
     */
    void disconnectedError();

    /**
     * Emitted when the view has a specific error.
     */
    void errorMessage(const QString &title, const QString &message);
 
    /**
     * Emitted when the status of the view changed.
     * @param s the new status
        */
    void statusChanged(RemoteView::RemoteStatus s);

    /**
     * Emitted when the password dialog is shown or hidden.
     * @param b true when the dialog is shown, false when it has been hidden
     */
    void showingPasswordDialog(bool b);

    /**
     * Emitted when the mouse on the remote side has been moved.
     * @param x the new x coordinate
     * @param y the new y coordinate
     * @param buttonMask the mask of mouse buttons (bit 0 for first mouse
     *                   button, 1 for second button etc)a
     */
    void mouseStateChanged(int x, int y, int buttonMask);

protected:
    RemoteView(QWidget *parent = 0);

    void focusInEvent(QFocusEvent *event);
    void focusOutEvent(QFocusEvent *event);

    /**
     * The status of the remote view.
     */
    RemoteStatus m_status;

    /**
     * Set the status of the connection.
     * Emits a statusChanged() signal.
     * Note that the states need to be set in a certain order,
     * see @ref Status. setStatus() will try to do this
     * transition automatically, so if you are in Connecting
     * and call setStatus(Preparing), setStatus() will
     * emit a Authenticating and then Preparing.
     * If you transition backwards, it will emit a
     * Disconnected before doing the transition.
     * @param s the new status
     */
    virtual void setStatus(RemoteStatus s);

    QCursor localDotCursor() const;

    QString m_host;
    int m_port;
    bool m_viewOnly;
    bool m_grabAllKeys;
    bool m_scale;
    bool m_keyboardIsGrabbed;
    KUrl m_url;

#ifndef QTONLY
    QString readWalletPassword(bool fromUserNameOnly = false);
    void saveWalletPassword(const QString &password, bool fromUserNameOnly = false);
    KWallet::Wallet *m_wallet;
#endif

    DotCursorState m_dotCursorState;
};

#endif