/*************************************************************************
 *                                                                       *
 *  SignServer: The OpenSource Automated Signing Server                  *
 *                                                                       *
 *  This software is free software; you can redistribute it and/or       *
 *  modify it under the terms of the GNU Lesser General Public           *
 *  License as published by the Free Software Foundation; either         *
 *  version 2.1 of the License, or any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.signserver.web;

import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.Random;

import javax.ejb.EJB;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;
import org.signserver.common.CryptoTokenOfflineException;
import org.signserver.common.IllegalRequestException;
import org.signserver.common.RequestContext;
import org.signserver.common.SignServerException;
import org.signserver.common.genericws.GenericWSRequest;
import org.signserver.ejb.interfaces.IWorkerSession;
import org.signserver.server.CertificateClientCredential;

/**
 * A special servlet used to support custom Jax-WS WebServices in
 * MAR modules. I.e instead of implementing a Worker it is possible
 * to just implement a JAX-WS WebService. This servlet does two
 * things.
 *   1. Extracts the worker name/id from the URL, signserver/ws/<name/id>/<servicename>
 *   2. Forwards the request/response objects to the worker.
 * 
 * @author Philip Vendil 8 okt 2008
 *
 * @version $Id: GenericWSServlet.java 3452 2013-04-20 21:32:59Z netmackan $
 */
public class GenericWSServlet extends HttpServlet implements ServletContextAttributeListener, ServletContextListener {

    private static final long serialVersionUID = 1L;
    
    /** Logger for this class. */
    private static final Logger LOG = Logger.getLogger(GenericWSServlet.class);
    
    private Random rand = new Random();
    
    @EJB
    private IWorkerSession.ILocal workersession;

    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        super.init(servletConfig);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException {
        forwardRequest(GenericWSRequest.REQUESTTYPE_POST, request, response, getServletContext());
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException {

        forwardRequest(GenericWSRequest.REQUESTTYPE_GET, request, response, getServletContext());
    }

    @Override
    protected void doPut(HttpServletRequest request, HttpServletResponse response)
            throws ServletException {
        forwardRequest(GenericWSRequest.REQUESTTYPE_PUT, request, response, getServletContext());
    }

    @Override
    protected void doDelete(HttpServletRequest request, HttpServletResponse response)
            throws ServletException {
        forwardRequest(GenericWSRequest.REQUESTTYPE_DEL, request, response, getServletContext());
    }

    /**
     * Main method that forwards the HTTP request to a given worker.
     * 
     * 
     * @param requestType on of GenericWSRequest.REQUESTTYPE_ constants
     * @param request the HTTP request
     * @param response the HTTP response.
     * @throws ServletException 
     */
    private void forwardRequest(int requestType, HttpServletRequest request, HttpServletResponse response, ServletContext servletContext) throws ServletException {
        LOG.debug(">forwardRequest");
        System.out.println("1");
        if (GenericWSRequest.REQUESTTYPE_CONTEXT_INIT != requestType
                && GenericWSRequest.REQUESTTYPE_CONTEXT_DESTROYED != requestType) {

            int workerId = getWorkerId(request);
            if (workerId == 0) {
                throw new ServletException("Error, couldn't parse worker name or id from request URI : " + request.getRequestURI());
            }

            String remoteAddr = request.getRemoteAddr();
            

            //
            Certificate clientCertificate = null;
            Certificate[] certificates = (X509Certificate[]) request.getAttribute("javax.servlet.request.X509Certificate");
            if (certificates != null) {
                clientCertificate = certificates[0];
            }
            RequestContext requestContext = new RequestContext(
                    (X509Certificate) clientCertificate, remoteAddr);

            if (clientCertificate instanceof X509Certificate) {
                final X509Certificate cert = (X509Certificate) clientCertificate;
                final CertificateClientCredential credential = new CertificateClientCredential(
                        cert.getSerialNumber().toString(16),
                        cert.getIssuerDN().getName());
                requestContext.put(RequestContext.CLIENT_CREDENTIAL, credential);
            }

            int requestId = rand.nextInt();

            GenericWSRequest wsreq = new GenericWSRequest(requestId, requestType, request, response, getServletConfig(), servletContext);
            try {
                getWorkerSession().process(workerId, wsreq, requestContext);
            } catch (IllegalRequestException e) {
                throw new ServletException(e);
            } catch (CryptoTokenOfflineException e) {
                throw new ServletException(e);
            } catch (SignServerException e) {
                throw new ServletException(e);
            }
        }
        LOG.debug("<forwardRequest");
    }

    /**
     * Method checking the URI and parses the worker name or worker id
     * from it to know to which worker to forward the WS call to.
     * @param request the http request
     * @return the workerId or 0 if no valid worker id could be parsed.
     */
    private int getWorkerId(HttpServletRequest request) {
        int retval = 0;

        String requestURI = request.getRequestURI();
        String[] splittedURI = requestURI.split("/");
        if (splittedURI.length > 2) {
            String workerPart = splittedURI[splittedURI.length - 2];
            try {
                retval = Integer.parseInt(workerPart);
            } catch (NumberFormatException e) {
            }

            if (retval == 0) {
                retval = getWorkerSession().getWorkerId(workerPart);
            }
        }

        return retval;
    }

    private IWorkerSession.ILocal getWorkerSession() {
        if (workersession == null) {
            try {
                Context context = new InitialContext();
                workersession = (org.signserver.ejb.interfaces.IWorkerSession.ILocal) context.lookup(IWorkerSession.ILocal.JNDI_NAME);
            } catch (NamingException e) {
                LOG.error(e);
            }
        }

        return workersession;
    }

    public void attributeAdded(ServletContextAttributeEvent arg0) {
        // Do Nothing		
    }

    public void attributeRemoved(ServletContextAttributeEvent arg0) {
        // Do Nothing		
    }

    public void attributeReplaced(ServletContextAttributeEvent arg0) {
        // Do Nothing		
    }

    public void contextDestroyed(ServletContextEvent event) {
        try {
            forwardRequest(GenericWSRequest.REQUESTTYPE_CONTEXT_DESTROYED, null, null, event.getServletContext());
        } catch (ServletException e) {
            LOG.error(e);
        }
    }

    public void contextInitialized(ServletContextEvent event) {
        try {
            forwardRequest(GenericWSRequest.REQUESTTYPE_CONTEXT_INIT, null, null, event.getServletContext());
        } catch (ServletException e) {
            LOG.error(e);
        }
    }
}