/*

* 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.game;

import java.util.Vector;

import javax.microedition.lcdui.Graphics;

/**

 * LayerManager class.

 */

public class LayerManager {

    private Vector layers;

    private int viewX;

    private int viewY;

    private int viewWidth = Integer.MAX_VALUE;

    private int viewHeight = Integer.MAX_VALUE;

    public LayerManager() {

        layers = new Vector();

    }

    public void append(Layer aLayer) {

        remove(aLayer);

        layers.addElement(aLayer);

    }

    public void insert(Layer layer, int index) {

        if (layer == null) {

            throw new NullPointerException(

                    MsgRepository.LAYERMANAGER_EXCEPTION_LAYER_NULL);

        }

        if (index < 0 || index > layers.size()) {

            throw new IndexOutOfBoundsException(

                    MsgRepository.LAYERMANAGER_EXCEPTION_INVALID_LAYER_INDEX);

        }

        if (index > layers.size() - 1 && layers.contains(layer)) {

            throw new IndexOutOfBoundsException(

                    MsgRepository.LAYERMANAGER_EXCEPTION_INVALID_LAYER_INDEX);

        }

        remove(layer);

        layers.insertElementAt(layer, index);

    }

    public void remove(Layer layer) {

        if (layer == null) {

            throw new NullPointerException(

                    MsgRepository.LAYERMANAGER_EXCEPTION_LAYER_NULL);

        }

        layers.removeElement(layer);

    }

    public Layer getLayerAt(int index) {

        return (Layer) layers.elementAt(index);

    }

    public int getSize() {

        return layers.size();

    }

    public void setViewWindow(int x, int y, int width, int height) {

        if (width < 0 || height < 0) {

            throw new IllegalArgumentException(

                    MsgRepository.LAYERMANAGER_EXCEPTION_INVALID_WIDTH_HEIGHT);

        }

        viewX = x;

        viewY = y;

        viewWidth = width;

        viewHeight = height;

    }

    public void paint(Graphics graphics, int x, int y) {

        // save Graphics clip and translate

        final int oldClipX = graphics.getClipX();

        final int oldClipY = graphics.getClipY();

        final int oldClipW = graphics.getClipWidth();

        final int oldClipH = graphics.getClipHeight();

        final int oldTransX = graphics.getTranslateX();

        final int oldTransY = graphics.getTranslateY();

        // intersect Graphics clip region with View Window

        graphics.clipRect(x, y, viewWidth, viewHeight);

        /*

         * translate the graphics object so the point (aX,aY) corresponds to the

         * location of the viewWindow in the coordinate system of the

         * LayerManager.

         */

        graphics.translate(-viewX, -viewY);

        // paint visible Layers

        Layer layer = null;

        for (int i = layers.size() - 1; i >= 0; i--) {

            layer = getLayerAt(i);

            if (layer.isVisible(graphics, x, y)) {

                graphics.translate(x, y);

                layer.paint(graphics);

                graphics.translate(-x, -y);

            }

        }

        // restore Graphics translation because translation is concatenated

        // need to translate back to 0,0 first

        graphics.translate(-graphics.getTranslateX(),

                -graphics.getTranslateY());

        // restore Graphics translate and clip

        graphics.translate(oldTransX, oldTransY);

        graphics.setClip(oldClipX, oldClipY, oldClipW, oldClipH);

    }

}