package org.apache.log4j.chainsaw.prefs;

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.DomDriver;

/**
 * Loads/Saves the MRU lists from preferences
 * 
 * @author psmith
 *
 */
public class MRUFileListPreferenceSaver implements SettingsListener{

    private static final MRUFileListPreferenceSaver instance = new MRUFileListPreferenceSaver();
    
    public static final MRUFileListPreferenceSaver getInstance() {
        return instance;
    }
    private MRUFileListPreferenceSaver() {}
    
    public void loadSettings(LoadSettingsEvent event) {
        File file = getMRULocation(SettingsManager.getInstance().getSettingsDirectory());
        if(file.exists()) {
            try {
                MRUFileList.loadLog4jMRUListFromReader(new FileReader(file));
            } catch (Exception e) {
//                TODO exception handling
                e.printStackTrace();
            }
        }
        
    }

    public void saveSettings(SaveSettingsEvent event) {
        XStream stream = new XStream(new DomDriver());
        try {
            File file = getMRULocation(event.getSettingsLocation());
            System.out.println("Writing MRU ->" + file.getAbsolutePath());
            FileWriter writer = new FileWriter(file);
            stream.toXML(MRUFileList.log4jMRU(), writer);
            writer.close();
        } catch (Exception e) {
//            TODO exception handling
            e.printStackTrace();
        }
    }
    private File getMRULocation(File dir) {
        File file = new File(dir, "mru.xml");
        return file;
    }

}