/* (c) 2014 Open Source Geospatial Foundation - all rights reserved
 * (c) 2001 - 2013 OpenPlans
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.vfny.geoserver.crs;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.logging.Level;

import org.geoserver.platform.GeoServerExtensions;
import org.geoserver.platform.GeoServerResourceLoader;
import org.geoserver.platform.resource.Resource;
import org.geoserver.platform.resource.Resource.Type;
import org.geotools.data.DataUtilities;
import org.geotools.referencing.factory.epsg.FactoryUsingWKT;


/**
 * Authority allowing users to define their own CRS in a separate file
 */
public class GeoserverCustomWKTFactory extends FactoryUsingWKT {
    public static final String SYSTEM_DEFAULT_USER_PROJ_FILE = "user.projections.file";

    /**
     * Returns the URL to the property file that contains CRS definitions. The
     * default implementation returns the URL to the {@value #FILENAME} file.
     *
     * @return The URL, or {@code null} if none.
     */
    protected URL getDefinitionsURL() {
        String cust_proj_file = System.getProperty(SYSTEM_DEFAULT_USER_PROJ_FILE);
        if (cust_proj_file == null) {
            GeoServerResourceLoader loader = GeoServerExtensions.bean(GeoServerResourceLoader.class);
            if( loader != null ){ // not available during construction SystemTestData - call CRS reset to fix
                Resource custom_proj = loader.get("user_projections/epsg.properties");
                if( custom_proj.getType() == Type.RESOURCE ){
                    cust_proj_file = custom_proj.file().getAbsolutePath();
                }
            }
        }
        if( cust_proj_file != null ){
            // Attempt to load user-defined projections
            File proj_file = new File(cust_proj_file);
            if (proj_file.exists()) {
                URL url = DataUtilities.fileToURL(proj_file);
                if( url != null ){
                    return url;
                }
                else {
                    LOGGER.log(Level.SEVERE, "Had troubles converting file name to URL");
                }
            }
        }
        // Use the built-in property defintions
        cust_proj_file = "user_epsg.properties";
        return GeoserverCustomWKTFactory.class.getResource(cust_proj_file);
    }
}