/*

* Copyright (c) 2009 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:

*

*/

package javax.microedition.lcdui;

import org.eclipse.swt.graphics.Point;

/**

 * Class representing the Gauge item.

 */

public class Gauge extends Item

{

    /**

     * Indefinite constant.

     */

    public static final int INDEFINITE = -1;

    /**

     * Continuous idle constant.

     */

    public static final int CONTINUOUS_IDLE = 0;

    /**

     * Incremental idle constant.

     */

    public static final int INCREMENTAL_IDLE = 1;

    /**

     * Continuous running constant.

     */

    public static final int CONTINUOUS_RUNNING = 2;

    /**

     * Incremental updating constant.

     */

    public static final int INCREMENTAL_UPDATING = 3;

    /**

     * If Gauge is changed, reasons for Re-layouting.

     */

	static final int UPDATE_MAXVALUE = UPDATE_ITEM_MAX << 1;

	static final int UPDATE_VALUE = UPDATE_ITEM_MAX << 2;

    private int maxValue;

    private int value;

    private boolean interactive;

    /**

     * Constructor.

     *

     * @param name the label.

     * @param interactive if its interactive.

     * @param maxVal the maximum value.

     * @param initVal the initial value.

     */

    public Gauge(String aName, boolean aInteractive, int aMaxVal, int aInitVal)

    {

        maxValue = validateMaxValue(aMaxVal, aInteractive);

		value = validateValue(aInitVal, maxValue);

		interactive = aInteractive;

        setLabel(aName);

    }

    /**

     * Sets value of this gauge.

     *

     * @param value New value. Must be between zero and maxvalue inclusive.

     */

    public void setValue(int aValue)

    {

        // TODO: eSWT support required

        /*

         * if Gauge state is incremental-updating and it is non-interactive and

         * indefinite, we should update Gauge when this method is called, but

         * that requires eSWT extension.

         */

        value = validateValue(aValue, maxValue);

        updateParent(UPDATE_VALUE);

    }

    /**

     * Get value.

     *

     * @return the value.

     */

    public int getValue()

    {

        return value;

    }

    /**

     * Set the maximum value.

     *

     * @param maxValue the maximum value.

     */

    public void setMaxValue(int aMaxValue)

    {

        updateParent(UPDATE_MAXVALUE);

    }

    /**

     * Get maximum value.

     *

     * @return the maximum value.

     */

    public int getMaxValue()

    {

        return maxValue;

    }

    /**

     * Checks if gauge is interactive.

     *

     * @return true if the Gauge is interactive.

     */

    public boolean isInteractive()

    {

        return interactive;

    }

    /**

     * Check maximum value validity.

     *

     * @param aMaxVal the maximum value.

     * @param aInteractive is interactive.

     * @return validated maximum value.

     */

    private int validateMaxValue(int aMaxVal, boolean aInteractive)

    {

        if((!aInteractive) && (aMaxVal == INDEFINITE))

        {

			return aMaxVal;

        }

        if(aMaxVal <= 0)

        {

            throw new IllegalArgumentException(

                MsgRepository.GAUGE_EXCEPTION_INVALID_MAXVALUE);

        }

        return aMaxVal;

    }

    /**

     * Check value validity.

     *

     * @param aValue the value.

     * @param aMaxVal the maximum value.

     * @return validated value.

     */

	private int validateValue(int aValue, int aMaxVal)

	{

		if (aMaxVal == INDEFINITE)

		{

			switch (aValue)

			{

			case CONTINUOUS_IDLE:

			case INCREMENTAL_IDLE:

			case CONTINUOUS_RUNNING:

			case INCREMENTAL_UPDATING:

				break;

			default:

				throw new IllegalArgumentException();

			}

			return aValue;

		}

		else

		{

			return clampValue(aValue, aMaxVal);

		}

	}

    /**

     * Check value validity.

     *

     * @param aValue the value.

     * @param aNewMaxVal the new maximum value.

     * @param aOlddMaxVal the old maximum value.

     * @return validated value.

     */

	private int validateValue(int aValue, int aNewMaxVal, int aOlddMaxVal)

	{

		if (aNewMaxVal == INDEFINITE)

		{

			return CONTINUOUS_IDLE;

		}

		else if (aOlddMaxVal == INDEFINITE)

		{

			return 0;

		}

		else

		{

			return clampValue(aValue, aNewMaxVal);

		}

	}

	  /**

	 * Validates the value against the range.

	 *

	 * @param aValue the value.

	 * @param aMaxVal the maximum value.

	 * @return validated value.

	 */

    private static int clampValue(int aValue, int aMaxVal)

    {

        aValue = Math.min(aValue, aMaxVal);

        aValue = Math.max(aValue, 0);

        return aValue;

    }

    /**

     * @return if the Gauge is indefinite.

     */

    boolean isIndefinite()

    {

        return (maxValue == INDEFINITE);

    }

    /* (non-Javadoc)

     * @see javax.microedition.lcdui.Item#isFocusable()

     */

    boolean isFocusable()

    {

        return (isInteractive() || (getNumCommands() > 0));

    }

    /**

     * Returns if this indicator meets the restrictions for its use in an Alert.

     */

    boolean isSuitableForAlert()

    {

        return (!isInteractive()

                && getParent() == null

                && getLabel() == null

                && getLayout() == Item.LAYOUT_DEFAULT

                && !isSizeLocked()

                && getNumCommands() == 0

                && getItemCommandListener() == null);

    }

    /**

     * Called by widget listeners to update Item value.

     */

    void internalSetValue(int newValue)

    {

        value = validateValue(newValue, maxValue);

		updateParent(UPDATE_VALUE);

        // notify item state listener

        notifyStateChanged();

    }

    /**

     * Return layout with optional custom flags.

     *

     * @return layout directive

     */

    int internalGetLayout()

    {

        return super.internalGetLayout() | Item.LAYOUT_NEWLINE_BEFORE;

    }

    /**

     * Updates Form or Alert.

     *

     * @see javax.microedition.lcdui.Item#updateParent(int)

     */

    void updateParent(int updateReason)

    {

        if(isContainedInAlert())

        {

            ((Alert) getParent()).updateIndicator();

        }

        else

        {

            super.updateParent(updateReason);

        }

    }

    /**

     * Calculates minimum size of this item.

     *

     * @return Minimum size.

     */

    Point calculateMinimumSize()

    {

        return GaugeLayouter.calculateMinimumBounds(this);

    }

    /**

     * Calculates preferred size of this item.

     *

     * @return Preferred size.

     */

    Point calculatePreferredSize()

    {

        return GaugeLayouter.calculatePreferredBounds(this);

    }

}