/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *         http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.argeo.slc.osgi;
  
  import java.io.File;
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.argeo.slc.SlcException;
  import org.argeo.slc.core.execution.FileExecutionResources;
  import org.eclipse.gemini.blueprint.context.BundleContextAware;
  import org.eclipse.gemini.blueprint.io.OsgiBundleResource;
  import org.osgi.framework.BundleContext;
  import org.springframework.core.io.Resource;
  
  /** Write access to resources in an OSGi context */
  public class OsgiExecutionResources extends FileExecutionResources implements
  		BundleContextAware {
  	private final static Log log = LogFactory
  			.getLog(OsgiExecutionResources.class);
  
  	private BundleContext bundleContext;
  
  	@Override
  	protected File fileFromResource(Resource resource) {
  		File file = super.fileFromResource(resource);
  		if (file != null)
  			return file;
  
  		if (!(resource instanceof OsgiBundleResource))
  			return null;
  
  		OsgiBundleResource osgiBundleResource = (OsgiBundleResource) resource;
  		try {
  			return osgiBundleResource.getFile();
  		} catch (IOException e) {
  			if (log.isTraceEnabled())
  				log.trace("Resource " + resource
  						+ " is not available on the file system: " + e);
  		}
  
  		// TODO: ability to access resources in other bundles
  		String location = bundleContext.getBundle().getLocation();
  		String base = null;
  		if (location.startsWith("reference:file:"))
  			base = location.substring("reference:file:".length());
  		else if (location.startsWith("initial@reference:file:")) {
  			// TODO: Equinox specific?
  			String relPath = location.substring("initial@reference:file:"
  					.length());
  			// if (relPath.startsWith("../"))// relative to the framework jar
  			// relPath = relPath.substring("../".length());
  			// String framework =
  			// System.getProperty("osgi.framework").substring(
  			// "file:".length());
  			// log.debug(framework);
  			String installArea = System.getProperty("osgi.install.area")
  					.substring("file:".length());
  			// log.debug(installArea);
  			base = installArea + '/' + relPath;
  			// int sepIndex = framework.lastIndexOf(File.separatorChar);
  			// framework = framework.substring(0, sepIndex);
  			// base = framework + '/' + relPath;
  		} else {
  			return null;
  		}
  
  		String path = base + '/' + osgiBundleResource.getPathWithinContext();
  		try {
  			file = new File(path).getCanonicalFile();
  		} catch (IOException e) {
  			throw new SlcException("Cannot determine canonical path for "
  					+ path, e);
  		}
  
  		if (!file.exists())
  			throw new SlcException(file
  					+ " was retrieved in bundle located at '" + location
  					+ "' for resource " + resource + " but it does not exist");
  
  		if (log.isTraceEnabled())
  			log.debug("OSGi local resource: " + file + " from " + resource);
  		return file;
  	}
  
 	public void setBundleContext(BundleContext bundleContext) {
 		this.bundleContext = bundleContext;
 	}
 
 }