/*

* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Gesture helper implementation

*

*/

#ifndef _GESTUREHELPERIMPL_H_

#define _GESTUREHELPERIMPL_H_

#include <e32base.h>

#include <coemain.h>

#include <rt_gesturehelper.h>

struct TPointerEvent;

namespace RT_GestureHelper

{

class CCallbackTimer;

class CGesture;

class CPointerCapturer;

class MGestureObserver;

class CGestureEventFilter;

class CGestureEventSender;

/**

 * Implementation of CGestureHelper interface

 */

NONSHARABLE_CLASS( CGestureHelperImpl ) : public CBase

    {

public:

    /** 2-phase constructor */

    static CGestureHelperImpl* NewL( MGestureObserver& aObserver );

    /** Destructor */

    ~CGestureHelperImpl();    

    /** See @ref CGestureHelper::SetHoldingEnabled */

    void SetHoldingEnabled( TBool aEnabled );

    /** See @ref CGestureHelper::IsHoldingEnabled */

    TBool IsHoldingEnabled() const;

    /** See @ref CGestureHelper::SetDoubleTapEnabled */

    void SetDoubleTapEnabled( TBool aEnabled );

    /** See @ref CGestureHelper::IsDoubleTapEnabled */

    TBool IsDoubleTapEnabled() const;

    /** See @ref CGestureHelper::HandlePointerEventL */

    TBool HandlePointerEventL( const TPointerEvent& aEvent );

    /** Reset helper state */

    void Reset();

    void SetLastEventTime() {iLastEventTime.HomeTime(); } /*CCoeEnv::Static()->LastEvent().Time();*/ 

    TTime GetLastEventTime() const { return iLastEventTime; }

private:

    /** Constructor */

    CGestureHelperImpl( MGestureObserver& aObserver );

    TBool noneAlf_HandlePointerEventL( const TPointerEvent& aEvent);

    /** @return ETrue if the helper has not started processing a gesture */

    inline TBool IsIdle() const;

    /** Add a point to the sequence of points that make up the gesture */

    inline void AddPointL( const TPointerEvent& aEvent );    

    /** Add a point to the sequence of points that make up the gesture */

    inline TInt AddPoint( const TPointerEvent& aEvent );    

    /** Activates holding and notifies observer that holding has been started */

    void StartHoldingL();

    /* Set previous tag gesture to null (and recycle the gesture object) */

    static void RecyclePreviousTapGesture( TAny* aSelf );

    /** Emits a tap event since second tap of a double tap was not received within timeout */

    /** Emit the start gesture event that aGesture would have produced */

    void EmitStartEventL( const CGesture& aGesture );

    /** 

     * Send code event if not holding. Also sets the event to released and emits again.

     * Modifies aGesture! 

     */

    /** 

     * Send cancel event about the latest gesture client was notified about 

     * Sets the latest gesture to Cancelled.

     */

    /**

     * Send Released event

     */

    /** Notify observer of the gesture */

    /** 

     * (re)start holding timer at the current point.

     * Does not restart holding if the point (in aEvent) is near enough to where holding 

     * was started earlier. (Allows small movement but still starting holding.

     */

    void StartHoldingTimer( const TPointerEvent& aNewEvent );

    /** 

     * @return a gesture object from the gesture pool 

     * Getting gestures from the gesture pool avoids the need to create gestures

     * after construction. There is max only one gesture object in the pool, 

     * but no more is needed 

     */

    CGesture* NewGesture();

    /** Move the gesture into the gesture pool, and set aGesturePointer to null */

    void RecycleGesture( CGesture*& aGesturePointer );

    void HandleTouchDownL(const TPointerEvent& aEvent);

    void HandleMoveL(const TPointerEvent& aEvent);

    TBool IsMovementGesture(TGestureCode aCode);

private:

    /// Gesture is the logical representation of a sequence of points arriving

    /// at certain times

    /// This is the current gesture

    CGesture* iGesture;

    /// Tap gesture of the previous gesture. Used when double tap is enabled.

    /// The gesture is cached, since it cannot be emitted until gesture helper

    /// knows whether the next gesture forms a double tap

    /// @see CGestureHelperImpl::iDoubleTapTimer

    CGesture* iPreviousTapGesture;

    /// This is a recyclable object pool with just one object.

    /// This class needs one or two gesture objects at any one time. There is one

    /// less error condition to handle if gesture objects are not created after

    /// construction. Therefore, if only one gesture object is needed at a specific,

    /// point in time, the unused gesture object is stored here.

    CGesture* iUnusedGesture;

    /// When double tap is enabled, a tap

    /// event (and it's released event) is only emitted after the double tap timeout

    /// passes. If user taps again before the timeout (in the same position),

    /// this gesture is emitted as a double tap (followed by the released event, 

    /// and the second tap is not emitted at all.

    /// If user taps, and then swipes before the double tap timeout, this tap

    /// event (and it's released event) event is emitted, and only then the swipe's

    /// down and drag events are emitted. In other words, if user presses down

    /// during the timeout, the down event it not emitted until the gesture

    /// helper knows that the gesture is not another tap.

    /// Behavior while double tap enabled:

    /// Swipe: Down + drag + up => emits down + swipe/cancel + released

    /// Tap: Down + up => emits down ... timeout ... + tap + released

    /// Double tap: Down + up + down + up => emits down ... double tap + released

    /// Tap + quick swipe: Down + up + down + drag + ... => emits down ... tap + up (for tap) + down (for swipe ) + drag + ...

    /// Double tap timer is cancelled when the second pointer down event is received,

    /// i.e., it does not matter if user does this: 

    /// down + up + down ... long wait ... + up. It's still a double tap.

    CCallbackTimer* iDoubleTapTimer;

    /// holding is activated when user keeps pointer down in the same place for 

    /// a longer period. the holding timer activates off when enough time has passed.

    CCallbackTimer* iHoldingTimer;

    /// observer for gesture events

    MGestureObserver& iObserver;

    /// captures subsequent pointer events after pointer down received,

    /// until pointer up

    CPointerCapturer* iPointerCapturer;

    TTime  iLastEventTime;

    TTime  iLastTouchUpTime;

    TTime  iLastDoubleTapTime;

    CCallbackTimer*  iLongTouchTimer;

    CGestureEventFilter* iEventFilter;

    CGestureEventSender* iEventSender;

    };

} // GestureHelper

#endif // _GESTUREHELPERIMPL_H_