package ua.nure.khmelik.SummaryTask4.web.filter;

import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;

public class LoginFilter implements Filter {

    private static final Logger LOGGER = Logger.getLogger(LoginFilter.class);

    private String excludePatterns;

    @Override
    public void init(FilterConfig cfg) throws ServletException {
	this.excludePatterns = cfg.getInitParameter("excludePatterns");
	LOGGER.debug("LoginFilter initialized.");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
	    FilterChain chain) throws IOException, ServletException {
	HttpServletRequest req = (HttpServletRequest) request;
	HttpServletResponse resp = (HttpServletResponse) response;
	HttpSession session = req.getSession();
	if (session.getAttribute("user") != null
		|| matchesExcludePatterns(req.getRequestURL())) {
	    chain.doFilter(request, response);
	} else if (req.getRequestURI().matches(".*(css|jpg|png|gif|js)")) {
	    LOGGER.debug("Loading js/css/gif/png/jsp files");
	    chain.doFilter(request, response);
	} else {
	    LOGGER.debug("No user logged in " + req.getRequestURI());
	    resp.sendRedirect("login");
	}
    }

    private boolean matchesExcludePatterns(StringBuffer requestURL) {
	Pattern pattern = Pattern.compile("(.)*(" + excludePatterns + ")(.)*");
	Matcher matcher = pattern.matcher(requestURL);
	LOGGER.debug("REQUESTED URL " + requestURL);
	return matcher.matches();
    }

    @Override
    public void destroy() {
	LOGGER.debug("LoginFilter instance destroyed.");
    }

}