/*

* Copyright (c) 2006-2007 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "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:   ?Description

*

*/

#ifndef __HUISCHEDULER_H__

#define __HUISCHEDULER_H__

#include <e32base.h>

#include <uiacceltk/HuiCommand.h>

#include <uiacceltk/HuiObserverArray.h>

/* Forward declaration. */

class CHuiEnv;

/**

 * The scheduler executes commands at certain points in time. There is one

 * scheduler instance created for each environment. Everyone has access to 

 * their environment's scheduler, and can send commands with it. Commands

 * include, for instance, visual animation commands and action commands sent

 * by controls. An action command would be sent, for example, when a menu 

 * item is selected or a button is pressed.

 */

NONSHARABLE_CLASS(CHuiScheduler) : public CBase

	{

public:

	/* Constructors and destructor. */

	/**

	 * Constructor. This is only done internally in the toolkit. Applications

	 * cannot construct schedulers.

	 *

	 * @param aEnv  Environment that owns the scheduler.

	 */

	CHuiScheduler(CHuiEnv& aEnv);

	/**

	 * Destructor.

	 */

	virtual ~CHuiScheduler();

	/* Methods. */

    /**

     * Called to notify the scheduler that time has passed and it may be 

     * necessary to trigger new animations and actions.

     *

     * @param aElapsedTime  Number of elapsed seconds.

     */

    void AdvanceTime(TReal32 aElapsedTime);	

    /**

     * Post a new command that will be executed immediately or after a

     * period of time.

     *

     * @param aCommand  Command to send.

     * @param aDelayMilliSeconds  Time to wait before executing.

     */

    void PostCommandL(const THuiCommand& aCommand, TInt aDelayMilliSeconds);

    /** 

     * Cancel all commands related to an object.

     *

     * @param aVisual  Visual.

     */     

    void CancelCommands(const TAny* aObject);

    /** 

     * Cancel commands related to an object.

     *

     * @param aVisual       Visual.

     & @param aCommandType  Type of command to cancel.

     */     

    void CancelCommands(const TAny* aObject, THuiOp aCommandOperation);

    /** 

     * Cancel commands related to a specific object.

     *

     * @param aControl      Control.

     * @param aCommandType  Type of command.

     * @param aParam        Parameter for custom event.

     */     

    void CancelCommands(const TAny* aObject, THuiCommandType aCommandType, TInt aParam);

    /**

     * Determines how much time is remaining until a command is to be

     * executed.

     *

     * @param aObject       Object.

     * @param aCommandType  Type of command.

     *     

     * @return  Time interval in milliseconds. -1, if no commands found.

     */

    TInt TimeUntilCommand(const TAny* aObject, THuiCommandType aCommandType);

    /**

     * Counts the number of pending commands.

     *

     * @return  Number of commands waiting to be executed.

     */

    TInt PendingCount() const;

private:

    /* Private methods */

    /**

     * Removes a pending command from the queue.

     *

     * @param aIndex  Index of the pending command.

     */

    void RemovePendingCommand(TInt aIndex);

private:

	/**

	 * A command to be executed at a certain point in time. A list of these delayed

	 * command events is stored in the HuiScheduler.

	 * 

	 */

    class TDelayedCommand

        {

    public:

    	/** Constructor. A command may be passed in the initialiser. */

        TDelayedCommand(const THuiCommand* aCommand)

                : iCommand(aCommand)

            {

            }

        /** The time when this command will be executed. */

        TTime iExecutionTime;

        /** 

         * The command that will be executed.

         * 

         * @see THuiCommand

         * */        

        const THuiCommand* iCommand;

        };

    /** Scheduler's environment. */

    CHuiEnv& iEnv;

    /** Pending commands waiting for execution. */

    RArray<TDelayedCommand> iPendingCommands;

	};

#endif  // __HUISCHEDULER_H__