/* 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.felix.http.jetty;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.security.*;

import org.mortbay.http.HttpException;
import org.mortbay.http.HttpRequest;
import org.mortbay.http.HttpResponse;
import org.mortbay.http.handler.AbstractHttpHandler;
import org.mortbay.jetty.servlet.*;

/**
 *
 */
public class OsgiResourceHandler extends AbstractHttpHandler
{
    protected org.osgi.service.http.HttpContext     m_osgiHttpContext;
    protected String                                m_name;
    protected OsgiServletHandler                    m_dummyHandler;
    protected AccessControlContext                  m_acc;

    
    public OsgiResourceHandler(
            org.osgi.service.http.HttpContext osgiHttpContext, String name,
            AccessControlContext acc)
    {
        m_osgiHttpContext = osgiHttpContext;
        m_name = name;
        // needed for OSGi security handling
        m_dummyHandler = new OsgiServletHandler(osgiHttpContext);
        m_acc = acc;
    }

    
    public void initialize(org.mortbay.http.HttpContext context)
    {
        super.initialize(context);
        m_dummyHandler.initialize(context);
    }

    
    public void handle(String pathInContext,
                       String pathParams,
                       HttpRequest request,
                       HttpResponse response)
        throws HttpException, IOException
    {
        Activator.debug("handle for name:" + m_name
                + "(path=" + pathInContext + ")");

        ServletHttpRequest servletRequest = new DummyServletHttpRequest(
                m_dummyHandler, pathInContext, request);
        ServletHttpResponse servletResponse = new DummyServletHttpResponse(
                servletRequest, response);

        if (!m_osgiHttpContext.handleSecurity(servletRequest, servletResponse))
        {
            // spec doesn't state specific processing here apart from 
            // "send the response back to the client". We take this to mean
            // any response generated in the context, and so all we do here
            // is set handled to "true" to ensure any output is sent back
            request.setHandled(true);
            return;
        }

        // Create resource based name and see if we can resolve it
        String resName = m_name + pathInContext;
        Activator.debug("** looking for: " + resName); 
        URL url = m_osgiHttpContext.getResource(resName);

        if (url == null)
        {
            return;
        }
        
        Activator.debug("serving up:" + resName);

        // It doesn't state so in the OSGi spec, but can't see how anything
        // other than GET and variants would be supported
        String method=request.getMethod();
        if (method.equals(HttpRequest.__GET) ||
            method.equals(HttpRequest.__POST) ||
            method.equals(HttpRequest.__HEAD))
        {
            handleGet(request, response, url, resName);
        }
        else
        {
            try
            {
                response.sendError(HttpResponse.__501_Not_Implemented);
            }
            catch(Exception e) {/*TODO: include error logging*/}
        }
    }

    
    public void handleGet(HttpRequest request, final HttpResponse response, 
            final URL url, String resName)
        throws IOException
    {
        String encoding = m_osgiHttpContext.getMimeType(resName);

        if (encoding == null)
        {
            encoding = getHttpContext().getMimeByExtension(resName);
        }

        if (encoding == null)
        {
            encoding = getHttpContext().getMimeByExtension(".default");
        }

        //TODO: not sure why this is needed, but sometimes get "IllegalState"
        // errors if not included
        response.setAcceptTrailer(true);
        response.setContentType(encoding);

        //TODO: check other http fields e.g. ranges, timestamps etc.

        // make sure we access the resource inside the bundle's access control
        // context if supplied
        if (System.getSecurityManager() != null)
        {
            try
            {
                AccessController.doPrivileged(new PrivilegedExceptionAction()
                {
                    public Object run()
                            throws Exception
                    {
                        copyResourceBytes(url, response);
                        return null;
                    }
                }, m_acc);
            } 
            catch (PrivilegedActionException ex) 
            {
                IOException ioe = (IOException) ex.getException();
                throw ioe;
            }
        }
        else
        {
            copyResourceBytes(url, response);
        }

        request.setHandled(true);
        //TODO: set other http fields e.g. __LastModified, __ContentLength
    }
    
    
    private void copyResourceBytes(URL url, HttpResponse response)
            throws
                    IOException
    {
        OutputStream os = response.getOutputStream();
        InputStream is = url.openStream();
        int len = 0;
        byte[] buf = new byte[1024];
        int n = 0;

        while ((n = is.read(buf, 0, buf.length)) >= 0)
        {
            os.write(buf, 0, n);
            len += n;
        }
        
        try 
        {
            response.setContentLength(len);
        } 
        catch (IllegalStateException ex) 
        {
            System.err.println("OsgiResourceHandler: " + ex);
        }
    }
}