package com.j2eegeek.servlet.filter;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.IOException;

/**
 * The <code>LoginCheckFilter</code> is a servlet filter that intercepts all inbound request to make sure the
 * access is authenticated.
 *
 * This work is licensed under a Creative Commons License.  More information at
 * <a href="http://creativecommons.org/licenses/by/1.0/">http://creativecommons.org/licenses/by/1.0/</A>
 *
 * @version 1.0
 * @since 03/10/2004
 * @author (<a href="mailto:vscarpenter@nospam.mailblocks.com">Vinny Carpenter</A>
 */
public class LoginCheckFilter implements javax.servlet.Filter {

    /** Private logger instance */
    private static final Log log = LogFactory.getLog(LoginCheckFilter.class);

    /** The servlet context that includes set of methods that a servlet uses to communicate with its servlet container */
    private ServletContext ctx;

    /** A filter configuration object used by the web container to pass information to a filter during initialization */
    private FilterConfig filterConfig;

    /**
     * Called by the web container to indicate to a filter that it is being placed into service. The servlet container
     * calls the init method exactly once after instantiating the filter. The init method must complete successfully
     * before the filter is asked to do any filtering work.
     * <P>
     * The web container cannot place the filter into service if the init method either
     * <OL>
     * <LI>Throws a ServletException
     * <LI>Does not return within a time period defined by the web container
     * </OL>
     *
     * @param filterConfig
     */
    public void init(FilterConfig filterConfig) {
        this.filterConfig = filterConfig;
        ctx = filterConfig.getServletContext();
        log.debug("LoginCheckFilter has been initialised");
    }


    /**
     * The <code>doFilter()</code> method performs the actual filtering work.  In its doFilter() method, each filter
     * receives the current request and response, as well as a FilterChain containing the filters that still must be
     * processed.
     * <P>
     * This filter is just used to capture and log information about the user being passed in to the login servlet
     * for tracking purposes.
     *
     * @param request Servlet request object
     * @param response Servlet response object
     * @param chain Filter chain
     * @exception IOException
     * @exception ServletException
     */
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
            throws IOException, ServletException {

        if (req != null) {
            HttpServletRequest request = (HttpServletRequest) req;
            //could pass in false in the getSession() to return null for new session.
            HttpSession mySession = request.getSession();
            String loginStatus = (String) mySession.getAttribute("LOGIN");

            if ((loginStatus != null) && (loginStatus.equals(Boolean.TRUE.toString()))) {
                log.debug("FOUND A LOGGED IN USER - PASSING THRU");
                //Logged in - Let's pass thru the user
                chain.doFilter(req, res);
            } else {
                log.debug("FOUND A NEW USER - CHECKING STATUS");
                if ((request.getRequestURI().indexOf("login") != -1) ||
                        (request.getRequestURI().indexOf("index.jsp") != -1) ||
                        (request.getRequestURI().indexOf("images") != -1) ||
                        (request.getRequestURI().indexOf("ipo.css") != -1)) {
                    //User is going to or being redirected to login page or loading images - Let's pass thru the user
                    log.debug("NEW USER -> LOADING CSS, IMAEGS or BEING REDIRECTED TO THE INDEX OR LOGIN PAGE");
                    log.debug("request.getRequestURI() = " + request.getRequestURI());
                    chain.doFilter(req, res);
                } else {
                    log.debug("NEW USER - LET's FORWARD TO THE INDEX JSP AGE");
                    log.debug("request.getRequestURI() = " + request.getRequestURI());
                    RequestDispatcher ds = ctx.getRequestDispatcher("/index.jsp?timeout=true");
                    ds.forward(request, res);
                }
            }
        }
    }

    public void setFilterConfig(FilterConfig filterConfig) {
    }


    /**
     * Called by the web container to indicate to a filter that it is being taken out of service. This method is only
     * called once all threads within the filter's doFilter method have exited or after a timeout period has passed.
     * After the web container calls this method, it will not call the doFilter method again on this instance of the
     * filter.
     * <P>
     * This method gives the filter an opportunity to clean up any resources that are being held (for example, memory,
     * file handles, threads) and make sure that any persistent state is synchronized with the filter's current state
     * in memory.
     */
    public void destroy() {
        this.filterConfig = null;
    }

}