/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org. All rights reserved.
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.web.util;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

import org.apache.wicket.IConverterLocator;
import org.apache.wicket.util.convert.IConverter;
import org.geoserver.platform.GeoServerResourceLoader;

/**
 * Special converter locator which can resolve relative urls relative to the
 * GeoServer data directory.
 * <p>
 * This converter locator will turn URL's of the form "file:data/..." into full
 * path URL's such as "file://var/lib/geoserver/data/...".
 *</p>
 * @author Justin Deoliveira, The Open Planning Project
 *
 */
@SuppressWarnings("serial")
public class DataDirectoryConverterLocator implements IConverterLocator {

    GeoServerResourceLoader resourceLoader;
    
    public DataDirectoryConverterLocator( GeoServerResourceLoader resourceLoader ) {
        this.resourceLoader = resourceLoader;
    }
    
    public IConverter getConverter(Class type) {
        if ( File.class.isAssignableFrom( type ) ) {
            return new FileLocator();
        }
        if ( URL.class.isAssignableFrom( type ) ) {
            return new URLLocator();
        }
        if ( URI.class.isAssignableFrom( type ) ) {
            return new URILocator();
        }
        
        return null;
    }

    File toFile( String value ) {
        if ( value == null || "".equals( value ) ) {
            return null;
        }
        try {
            //first try as a url to strip off url protocol prefix
            try {
                URL url = new URL( value );
                if ( "file".equals( url.getProtocol() ) ) {
                    value = url.getFile();
                }
            }
            catch( MalformedURLException e ) {}
            
            File file = new File( value );
            if ( file.isAbsolute() ) {
                return file;
            }

            return resourceLoader.find( value );
        } 
        catch (IOException e) {
            //TODO: log this
        }
        
        return null;
    }
    
    String fromFile( File file ) {
        File data = resourceLoader.getBaseDirectory();
        
        //figure out if the file is a child of the base data directory
        List<String> path = new ArrayList<String>();
        boolean isChild = false;
        while( file != null ) {
            if ( file.equals( data ) ) {
                isChild = true;
                break;
            }
            
            path.add( file.getName() );
            file = file.getParentFile();
        }
        
        if ( isChild ) {
            StringBuffer b = new StringBuffer( "file:" );
            for ( int i = path.size()-1; i > -1; i--)  {
                b.append( path.get( i ) ).append( File.separatorChar );
            }
            b.setLength( b.length()-1 );
            return b.toString();
        }
        
        return null;
    }
    
    class FileLocator implements IConverter {

        public Object convertToObject(String value, Locale locale) {
            return toFile( value );
        }

        public String convertToString(Object value, Locale locale) {
            return fromFile( (File) value );
        }
        
    }
    
    class URLLocator implements IConverter {

        public Object convertToObject(String value, Locale locale) {
            File file = toFile( value );
            if ( file != null ) {
                try {
                    return file.toURL();
                } 
                catch (MalformedURLException e) {
                    //TODO: log this
                }
            }
            
            return null;
        }

        public String convertToString(Object value, Locale locale) {
            URL url = (URL) value;
            String file = url.getFile();
            if ( file != null && !"".equals( file ) ) {
                return fromFile( new File( url.getFile() ) );
            }
            return null;
        }
        
    }
    
    class URILocator implements IConverter {

        public Object convertToObject(String value, Locale locale) {
            File file = toFile( value );
            if ( file != null ) {
                return file.toURI();
            }
            
            return null;
        }

        public String convertToString(Object value, Locale locale) {
            URI uri = (URI) value;
            try {
                return new URLLocator().convertToString( uri.toURL() , locale );
            } 
            catch (Exception e) {
                return null;
            }
        }
        
    }
}