/*******************************************************************************

 * Copyright (c) 2000, 2009 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.core.internal.resources;

import java.io.IOException;

import java.net.*;

import org.eclipse.core.internal.boot.PlatformURLConnection;

import org.eclipse.core.internal.boot.PlatformURLHandler;

import org.eclipse.core.internal.utils.Messages;

import org.eclipse.core.resources.*;

import org.eclipse.core.runtime.IPath;

import org.eclipse.core.runtime.Path;

import org.eclipse.osgi.util.NLS;

/**

 * Platform URL support

 * platform:/resource/<path>/<resource>  maps to resource in current workspace

 */

public class PlatformURLResourceConnection extends PlatformURLConnection {

	// resource/ protocol

	public static final String RESOURCE = "resource"; //$NON-NLS-1$

	public static final String RESOURCE_URL_STRING = PlatformURLHandler.PROTOCOL + PlatformURLHandler.PROTOCOL_SEPARATOR + '/' + RESOURCE + '/';

	private static URL rootURL;

	public PlatformURLResourceConnection(URL url) {

		super(url);

	}

	protected boolean allowCaching() {

		return false; // don't cache, workspace is local

	}

	protected URL resolve() throws IOException {

		String filePath = url.getFile().trim();

		filePath = URLDecoder.decode(filePath, "UTF-8"); //$NON-NLS-1$

		IPath spec = new Path(filePath).makeRelative();

		if (!spec.segment(0).equals(RESOURCE))

			throw new IOException(NLS.bind(Messages.url_badVariant, url));

		int count = spec.segmentCount();

		// if there is only one segment then we are talking about the workspace root.

		if (count == 1)

			return rootURL;

		// if there are two segments then the second is a project name.

		IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(spec.segment(1));

		if (!project.exists()) {

			String message = NLS.bind(Messages.url_couldNotResolve_projectDoesNotExist, project.getName(), url.toExternalForm());

			throw new IOException(message);

		}

		IResource resource = null;

		IPath result = null;

		if (count == 2) {

			resource = project;

		} else {

			spec = spec.removeFirstSegments(2);

			resource = project.getFile(spec);

		}

		result = resource.getLocation();

		if (result == null) {

			URI uri = resource.getLocationURI();

			if (uri != null) {

				try {

					URL url2 = uri.toURL();

					if (url2.getProtocol().equals("file")) //$NON-NLS-1$

						return url2;

				} catch (MalformedURLException e) {

					String message = NLS.bind(Messages.url_couldNotResolve_URLProtocolHandlerCanNotResolveURL, uri.toString(), url.toExternalForm());

					throw new IOException(message);

				}

			}

			String message = NLS.bind(Messages.url_couldNotResolve_resourceLocationCanNotBeDetermined, resource.getFullPath(), url.toExternalForm());

			throw new IOException(message);

		}

		return new URL("file", "", result.toString()); //$NON-NLS-1$ //$NON-NLS-2$

	}

	/**

	 * This method is called during resource plugin startup() initialization.

	 * 

	 * @param root URL to the root of the current workspace.

	 */

	public static void startup(IPath root) {

		// register connection type for platform:/resource/ handling

		if (rootURL != null)

			return;

		try {

			rootURL = root.toFile().toURL();

		} catch (MalformedURLException e) {

			// should never happen but if it does, the resource URL cannot be supported.

			return;

		}

		PlatformURLHandler.register(RESOURCE, PlatformURLResourceConnection.class);

	}

}