package org.gisandchips.gwt.maps.wms.client;

import com.google.gwt.maps.client.TileLayer;
import com.google.gwt.maps.client.geom.LatLng;
import com.google.gwt.maps.client.geom.MercatorProjection;
import com.google.gwt.maps.client.geom.Point;
import com.google.gwt.maps.client.geom.Projection;

public class WMSTileLayer extends TileLayer{
	private String baseServerUrl;
	private String layers;
	private String styles; 
	private Projection projection;
	
	private String getMapUrl = null;
	

	public WMSTileLayer(String baseServerUrl, String layers, String styles, Projection projection)
	{
		super(null, 0, 20);
		this.baseServerUrl = baseServerUrl;
		this.layers = layers;
		this.styles = styles;	

		//construct the base URL
		String urlBase = baseServerUrl + "?" +
		"FORMAT=image/png&SERVICE=WMS&REQUEST=GetMap&WIDTH=256&HEIGHT=256&VERSION=1.1.0&" +
		"STYLES=" + styles + "&" +
		"LAYERS="+ layers + "&";	

		getMapUrl = urlBase;
	}

	@Override
	public String getTileURL(Point tile, int zoom) {
		
		//Transforma las coordenadas a coordenadas Lat/Lon
		Point tileIndexLLPoint = Point.newInstance(tile.getX() * 256, (tile.getY() + 1) * 256);
		Point tileIndexURPoint = Point.newInstance(((tile.getX() + 1) * 256), (tile.getY()) * 256);
		LatLng llPoint = projection.fromPixelToLatLng(tileIndexLLPoint, zoom, true);
		LatLng urPoint = projection.fromPixelToLatLng(tileIndexURPoint, zoom, true);	
					
		String url =  getMapUrl + "SRS=EPSG:4326&BBOX=" + 
			llPoint.getLongitude() + "," + 
			llPoint.getLatitude() + "," +
			urPoint.getLongitude() + "," + 			
			urPoint.getLatitude();
		
		return url;
	}   	

	@Override
	public double getOpacity() {		
		return 1.0;
	}	

	@Override
	public boolean isPng() {		
		return true;
	}
}