package com.jeeww.core.security;

import java.io.IOException;
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 org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

public class WebFilterSecurityInterceptor extends AbstractSecurityInterceptor implements Filter {
	// ~ Static fields/initializers
	// =====================================================================================

	private static final String						FILTER_APPLIED			= "__spring_security_filterSecurityInterceptor_filterApplied";

	// ~ Instance fields
	// ================================================================================================

	private FilterInvocationSecurityMetadataSource	securityMetadataSource;
	private boolean									observeOncePerRequest	= true;

	// ~ Methods
	// ========================================================================================================

	/**
	 * Not used (we rely on IoC container lifecycle services instead)
	 * 
	 * @param arg0
	 *            ignored
	 * 
	 * @throws ServletException
	 *             never thrown
	 */
	public void init(FilterConfig arg0) throws ServletException {
	}

	/**
	 * Not used (we rely on IoC container lifecycle services instead)
	 */
	public void destroy() {
	}

	/**
	 * Method that is actually called by the filter chain. Simply delegates to
	 * the {@link #invoke(FilterInvocation)} method.
	 * 
	 * @param request
	 *            the servlet request
	 * @param response
	 *            the servlet response
	 * @param chain
	 *            the filter chain
	 * 
	 * @throws IOException
	 *             if the filter chain fails
	 * @throws ServletException
	 *             if the filter chain fails
	 */
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		invoke(fi);
	}

	public FilterInvocationSecurityMetadataSource getSecurityMetadataSource() {
		return this.securityMetadataSource;
	}

	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return this.securityMetadataSource;
	}

	public void setSecurityMetadataSource(FilterInvocationSecurityMetadataSource newSource) {
		this.securityMetadataSource = newSource;
	}

	public Class<?> getSecureObjectClass() {
		return FilterInvocation.class;
	}

	public void invoke(FilterInvocation fi) throws IOException, ServletException {
		if ((fi.getRequest() != null) && (fi.getRequest().getAttribute(FILTER_APPLIED) != null) && observeOncePerRequest) {
			// filter already applied to this request and user wants us to
			// observe
			// once-per-request handling, so don't re-do security checking
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
		} else {
			// first time this request being called, so perform security
			// checking
			if (fi.getRequest() != null) {
				fi.getRequest().setAttribute(FILTER_APPLIED, Boolean.TRUE);
			}

			InterceptorStatusToken token = super.beforeInvocation(fi);

			try {
				fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
			} finally {
//				super.finallyInvocation(token);
			}

			super.afterInvocation(token, null);
		}
	}

	/**
	 * Indicates whether once-per-request handling will be observed. By default
	 * this is <code>true</code>, meaning the
	 * <code>FilterSecurityInterceptor</code> will only execute
	 * once-per-request. Sometimes users may wish it to execute more than once
	 * per request, such as when JSP forwards are being used and filter security
	 * is desired on each included fragment of the HTTP request.
	 * 
	 * @return <code>true</code> (the default) if once-per-request is honoured,
	 *         otherwise <code>false</code> if
	 *         <code>FilterSecurityInterceptor</code> will enforce
	 *         authorizations for each and every fragment of the HTTP request.
	 */
	public boolean isObserveOncePerRequest() {
		return observeOncePerRequest;
	}

	public void setObserveOncePerRequest(boolean observeOncePerRequest) {
		this.observeOncePerRequest = observeOncePerRequest;
	}
}
