/*

* 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;

    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 name, boolean interactive, int maxVal, int initVal) {

        setLabel(name);

        this.interactive = interactive;

        setMaxValue(maxVal);

        setValue(initVal);

    }

    /**

     * Check value validity.

     *

     * @param value the value.

     * @param maxVal the maximum value.

     * @return validated value.

     */

    private static int checkValue(int value, int maxVal) {

        if (maxVal == INDEFINITE) {

            switch (value) {

                case CONTINUOUS_IDLE:

                case INCREMENTAL_IDLE:

                case CONTINUOUS_RUNNING:

                case INCREMENTAL_UPDATING:

                    break;

                default:

                    throw new IllegalArgumentException(

                            MsgRepository.GAUGE_EXCEPTION_INVALID_VALUE);

            }

            return value;

        }

        else {

            // make sure the value is in [0, maxValue] range

            value = (value < 0 ? 0 : value);

            value = (value > maxVal ? maxVal : value);

            return value;

        }

    }

    /**

     * Check maximum value validity.

     *

     * @param maxVal the maximum value.

     * @param interactive is interactive.

     * @return validated maximum value.

     */

    private static int checkMaxValue(int maxVal, boolean interactive) {

        if (!interactive) {

            if (maxVal == INDEFINITE) {

                return maxVal;

            }

        }

        if (maxVal <= 0) {

            throw new IllegalArgumentException(

                    MsgRepository.GAUGE_EXCEPTION_INVALID_MAXVALUE);

        }

        return maxVal;

    }

    /**

     * Sets value of this gauge.

     *

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

     */

    public void setValue(int value) {

        // 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.

         */

        this.value = checkValue(value, this.maxValue);

        updateParent(UPDATE_CONTENT);

    }

    /**

     * Get value.

     *

     * @return the value.

     */

    public int getValue() {

        return value;

    }

    /**

     * Set the maximum value.

     *

     * @param maxValue the maximum value.

     */

    public void setMaxValue(int maxValue) {

        this.maxValue = checkMaxValue(maxValue, interactive);

        this.value = checkValue(getValue(), this.maxValue);

        updateParent(UPDATE_CONTENT);

    }

    /**

     * 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;

    }

    /**

     * 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);

    }

    /**

     * Called by widget listeners to update Item value.

     */

    void internalSetValue(int newValue) {

        this.value = checkValue(newValue, this.maxValue);

        // notify item state listener

        notifyStateChanged();

    }

    /**

     * Return layout with optional custom flags.

     *

     * @return layout directive

     */

    int internalGetLayout() {

        return super.internalGetLayout() | Item.LAYOUT_NEWLINE_BEFORE;

    }

    /**

     * @return if the Gauge is indefinite.

     */

    boolean isIndefinite() {

        return (maxValue == INDEFINITE);

    }

    /**

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

     */

    boolean isSuitableForAlert() {

        return (!isInteractive()

                && getParent() == null

                && !hasLabel()

                && getLayout() == Item.LAYOUT_DEFAULT

                && !isSizeLocked()

                && getNumCommands() == 0

                && getItemCommandListener() == null);

    }

    /* (non-Javadoc)

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

     */

    boolean isFocusable() {

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

    }

}