/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.ant.internal.ui.preferences;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import org.eclipse.ant.internal.ui.AntUIPlugin;
import org.eclipse.jface.preference.StringButtonFieldEditor;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.DirectoryDialog;

public class URLFieldEditor extends StringButtonFieldEditor {
	
	public URLFieldEditor(String name, String labelText, Composite parent) {
		super(name, labelText, parent);
		setEmptyStringAllowed(false);
		setChangeButtonText(JFaceResources.getString("openBrowse"));//$NON-NLS-1$
		setErrorMessage(AntPreferencesMessages.URLFieldEditor_0);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.preference.StringFieldEditor#doCheckState()
	 */
	protected boolean doCheckState() {
		String text= getTextControl().getText();
		if (text != null && text.length() > 0) {
			try {
				new URL(text);
			} catch (MalformedURLException e) {
				return false;
			}
		}
		return true;
	}
	
	/* (non-Javadoc)
     * Method declared on StringButtonFieldEditor.
     * Opens the directory chooser dialog and returns the <code>URL</code> of the selected directory.
     */
    protected String changePressed() {
    	URL url= null;
		try {
			url = new URL(getTextControl().getText());
		} catch (MalformedURLException e1) {
		}
		File f = null;
		if (url != null) {
			f= new File(url.getFile());
			if (!f.exists()) {
	            f = null;
	        }
		}
        
        File d = getDirectory(f);
        if (d == null) {
            return null;
        }

        try {
			return d.toURL().toExternalForm();
		} catch (MalformedURLException e) {
			AntUIPlugin.log("Internal error setting documentation location", e); //$NON-NLS-1$
			return null;
		}
    }
    
    /**
     * Helper that opens the directory chooser dialog.
     * @param startingDirectory The directory the dialog will open in.
     * @return File File or <code>null</code>.
     */
    private File getDirectory(File startingDirectory) {

        DirectoryDialog fileDialog = new DirectoryDialog(getShell(), SWT.OPEN);
        if (startingDirectory != null) {
            fileDialog.setFilterPath(startingDirectory.getPath());
        }
        String dir = fileDialog.open();
        if (dir != null) {
            dir = dir.trim();
            if (dir.length() > 0) {
                return new File(dir);
            }
        }

        return null;
    }
}