/*
 * Copyright 2014 Federal Chancellery Austria
 * MOA-ID has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 */
package at.gv.egovernment.moa.id.auth.servlet.interceptor;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

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 org.springframework.context.ApplicationContext;

import at.gv.egiz.eaaf.core.impl.utils.HTTPUtils;
import at.gv.egovernment.moa.id.commons.api.AuthConfiguration;
import at.gv.egovernment.moa.id.commons.api.exceptions.ConfigurationException;
import at.gv.egovernment.moa.logging.Logger;

/**
 * @author tlenz
 *
 */
public class VHostUrlRewriteServletFilter implements Filter {

	private static final String VHOST_PATH = "/vhost/";
	private static final String AUTHURL = "authURL";
	
	
	private ApplicationContext context = null;
	
	public VHostUrlRewriteServletFilter(ApplicationContext context) {
		Logger.info("Register vHost Servelt Filter");
		this.context = context;
		
	}
	
	/* (non-Javadoc)
	 * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
	 */
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {

	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
	 */
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		 HttpServletRequest httpReq = (HttpServletRequest) request;		 
		 try {
			 AuthConfiguration authConfig = context.getBean(AuthConfiguration.class); 
			 List<String> configuredPublicURLPrefix = authConfig.getPublicURLPrefix();
		
			 //check if End-Point is valid		
			 String publicURLString = HTTPUtils.extractAuthURLFromRequest(httpReq);
			 URL publicURL;
			 try {
				 publicURL = new URL(publicURLString);
					
			 } catch (MalformedURLException e) {
				 Logger.error("IDP AuthenticationServiceURL Prefix is not a valid URL." + publicURLString, e);
				 throw new ConfigurationException("1299", null, e);
					
			 }
			 
			 //check if virtual IDPs are enabled
			 if (!authConfig.isVirtualIDPsEnabled()) {
				 Logger.trace("Virtual IDPs are disabled. Use default IDP PublicURLPrefix from configuration: " + configuredPublicURLPrefix.get(0));
				 httpReq.setAttribute(AUTHURL, configuredPublicURLPrefix.get(0));
				 chain.doFilter(request, response);
				
			 } else {				 
				String authURLString = HTTPUtils.extractAuthServletPathFromRequest(httpReq);
				 URL authURL;
				 try {
					 authURL = new URL(authURLString);
						
				 } catch (MalformedURLException e) {
					 Logger.error("IDP AuthenticationServiceURL Prefix is not a valid URL." + authURLString, e);
					 throw new ConfigurationException("1299", null, e);
						
				 } 
								
				Logger.debug("Extract AuthenticationServiceURL: " + authURLString);
				URL resultURL = null;
					
				for (String el : configuredPublicURLPrefix) {
					try {
						URL configuredURL = new URL(el);

						//get Ports from URL
						int configPort = configuredURL.getPort();					
						if (configPort == -1)
							configPort = configuredURL.getDefaultPort();
							
						int authURLPort = authURL.getPort();
						if (authURLPort == -1)
							authURLPort = authURL.getDefaultPort();
							
						//check AuthURL against ConfigurationURL
						if (configuredURL.getHost().equals(authURL.getHost()) &&
								configPort == authURLPort &&
								authURL.getPath().startsWith(configuredURL.getPath())) {
							Logger.debug("Select configurated PublicURLPrefix: " + configuredURL 
									+ " for authURL: " + authURLString);
							resultURL = configuredURL;
						}
							
					} catch (MalformedURLException e) {
							Logger.error("Configurated IDP PublicURLPrefix is not a valid URL." + el);
							
					}				
				}
								
				if (resultURL == null) {
					Logger.warn("Extract AuthenticationServiceURL: " + authURL + " is NOT found in configuration.");
					throw new ConfigurationException("config.25", new Object[]{authURLString});
						
				} else {
					httpReq.setAttribute(AUTHURL, resultURL.toExternalForm());
						
				}
				 				 				 
				String servletPath = httpReq.getServletPath();				 								 
				if (servletPath.startsWith(VHOST_PATH)) {
					Logger.trace("Found V-IDP selection via REST URL ... ");
					String vHostDescriptor = resultURL.toExternalForm().substring(0, publicURLString.length());
					String requestedServlet = authURLString.substring(0, vHostDescriptor.length());
					String newURL = publicURL.toExternalForm().concat(requestedServlet);
					httpReq.setAttribute(AUTHURL, newURL);
					httpReq.getRequestDispatcher(newURL).forward(httpReq, response);
										 
				} else {
					Logger.trace("Found V-IDP selection via Domain ...");
					chain.doFilter(request, response);
					
				}
				 				
			 }
		 
		 } catch (ConfigurationException e) {
			 
			 
		 }
		 		 			     
	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#destroy()
	 */
	@Override
	public void destroy() {
		// TODO Auto-generated method stub

	}

}