/*  Package GeoTools/WMS Implementation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * $Id: WebServiceLayer.java,v 1.7 2002/03/01 19:54:16 jmacgill Exp $
 * $Author: jmacgill $
 * $Date: 2002/03/01 19:54:16 $
 */

package uk.ac.leeds.ccg.ogc;

import uk.ac.leeds.ccg.geotools.*;
import uk.ac.leeds.ccg.raster.*;
import java.net.*;
import java.util.*;
import java.awt.image.*;
import java.awt.*;

/**
 * Class <code>WebServiceLayer</code> provides mechanisms for layers that
 * are built from URL addressable services.  In particular, it provides
 * the double buffering required.  Web Services Layers take a long time to
 * build, and consequently require double buffering which allows the old frame
 * to be viewed while the new frame is being built.<br>
 * WebServicesLayer is abstract, and hence cannot be used by itself.  It needs
 * to be extented and buildLayer needs to be specified for each extention of
 * this class.
 *
 * @author <a href="mailto:camerons@users.sourceforge.net">Cameron Shorter</a>
 * @version $Revision: 1.7 $
 */
public abstract class WebServiceLayer extends MultiLayer
{
    private final static boolean DEBUG=true;
    /** The extent of this layer last time it was called */
    private GeoRectangle oldExtent = null;
    static int layerid=0;
    /** Create a new sub-layer based on the extent passed in.
     * This method needs to be over-ridden by the extending class.
     * @param gg Information (mainly extent) required for building a new layer.
     */
    public abstract Layer buildLayer(GeoGraphics gg);


    /** This method provides double buffering for the layer used in
     * buildLayer, it assumes that if extent has not changed, then the
     * subLayer does not need to be rebuilt (just redrawn).  This will cover
     * 98% of cases, however there will be some dynamic layers, like Web Map
     * Servers which show time changing weather data, which will not work
     * properly with this implementation.  Hence, a more sophisticated
     * solution should be introduced at a later stage.
     * @author Cameron Shorter
     */
    public void paintScaled(GeoGraphics gg)
    {
        GeoRectangle extent;
        Vector layers;

        extent = gg.getScale().getMapExtent();
        if (extent==null||extent.isEmpty()){
            if(DEBUG)System.out.println("WebServiceLayer.bbox not defined");
            return;
        }
        layers = this.getLayers();

        if (DEBUG)
            if((layers.size()>0))System.out.println(
                "WebServiceLayer - "
                +" layers.size="+layers.size()
                +" firstElement.status="+((Layer)layers.firstElement()).getStatus()
                +" lastElement.status="+((Layer)layers.lastElement()).getStatus()
                +" extent.equals(oldExtent)="+extent.equals(oldExtent)
            );
            else System.out.println("WebServiceLayer - size=0"
                +" extent.equals(oldExtent)="+extent.equals(oldExtent));


        // if ("no layers") addLayer()
        if (layers.isEmpty())
        {
            if(DEBUG)System.out.println("WebServiceLayer: no layers");
            Layer x = buildLayer(gg);
            x.setName(""+layerid++);
            this.addLayer(x,true);
        }

        // if ("one layer loading") {removeLayer;addLayer}
        else if (
                (layers.size()==1)
                && (((Layer)layers.firstElement()).getStatus()!=Layer.COMPLETED)
                )
        {
            if(DEBUG)System.out.println("WebServiceLayer: one layer loading");
            if (!extent.equals(this.oldExtent)) {
                this.removeLayer((Layer)layers.firstElement(),true);
                Layer x = buildLayer(gg);
                x.setName(""+layerid++);
                this.addLayer(x,true);
            }
        }

        // ("one layer loaded") {paint the layer, start getting a new layer}
        else if (
                (layers.size()==1)
                && (((Layer)layers.firstElement()).getStatus()==Layer.COMPLETED)
                )
        {
            if(DEBUG)System.out.println("WebServiceLayer: one layer loaded");
            ((Layer)layers.firstElement()).paintScaled(gg);
            if (!extent.equals(this.oldExtent)) {
                Layer x = buildLayer(gg);
                x.setName(""+layerid++);
                this.addLayer(x,true);
            }
        }

        // ("one layer loaded, one loading") {paint layer1, get layer2 again}
        else if (
                (layers.size()==2)
                && (((Layer)layers.firstElement()).getStatus()==Layer.COMPLETED)
                && (((Layer)layers.lastElement()).getStatus()!=Layer.COMPLETED)
                )
        {
            if(DEBUG)System.out.println("WebServiceLayer: one layer loaded, one loading");
            ((Layer)layers.firstElement()).paintScaled(gg);
            if (!extent.equals(this.oldExtent)) {
                this.removeLayer((Layer)layers.lastElement(),true);
                Layer x = buildLayer(gg);
                x.setName(""+layerid++);
                this.addLayer(x,true);
            }
        }

        // ("2 layers loaded") {repaint last layer, remove first, get new layer}
        else if (
                (layers.size()==2)
                && (((Layer)layers.firstElement()).getStatus()==Layer.COMPLETED)
                && (((Layer)layers.lastElement()).getStatus()==Layer.COMPLETED)
                )
        {
            if(DEBUG)System.out.println("WebServiceLayer: 2 layers loaded");
            ((Layer)layers.lastElement()).paintScaled(gg);
            this.removeLayer((Layer)layers.firstElement(),true);
            if (!extent.equals(this.oldExtent)) {
                Layer x = buildLayer(gg);
                x.setName(""+layerid++);
                this.addLayer(x,true);
            }
        }

        else if(DEBUG)System.out.println(
            "WebServiceLayer - unexpected paintScaled options"
            +" layers.size="+layers.size()
            +" firstElement.status="+((Layer)layers.firstElement()).getStatus()
            +" lastElement.status="+((Layer)layers.lastElement()).getStatus()
        );
        this.oldExtent=extent;
    }
/*
    protected void paintScaled(Graphics g, Scaler scale, Shader shade,
            GeoData data, ShadeStyle style){
        if (DEBUG) System.out.println("WebServiceLayer.paintScaled2 ");
        GeoGraphics gg = new GeoGraphics(g,scale,shade,data,style,null,0);
        this.paintScaled(gg);
    }
 */
}

/*
 * Changes in file:
 *
 * $Log: WebServiceLayer.java,v $
 * Revision 1.7  2002/03/01 19:54:16  jmacgill
 *
 * removed outdated paintscaled method
 *
 * Revision 1.6  2002/01/31 10:21:48  ianturton
 * Added a layerid to use as the name of a layer to aid debugging.
 *
 * Revision 1.5  2001/11/21 13:48:19  kobit
 * Added support for creating ImageLayer with InputStream as image data source and full support for downaloding map data from WMS with jprotocols package
 *
 * Revision 1.4  2001/10/24 09:40:18  kobit
 * Added LOG cvs keyword to the end of file
 *
 *
 */