/*
 * 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.configuration.auth.pvp2.servlets;

import java.io.IOException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringEscapeUtils;
import org.opensaml.common.SAMLObject;
import org.opensaml.common.binding.BasicSAMLMessageContext;
import org.opensaml.saml2.binding.encoding.HTTPSOAP11Encoder;
import org.opensaml.saml2.core.LogoutRequest;
import org.opensaml.saml2.core.LogoutResponse;
import org.opensaml.ws.message.decoder.MessageDecodingException;
import org.opensaml.ws.message.encoder.MessageEncodingException;
import org.opensaml.ws.soap.client.BasicSOAPMessageContext;
import org.opensaml.ws.soap.soap11.Envelope;
import org.opensaml.ws.soap.soap11.decoder.http.HTTPSOAP11Decoder;
import org.opensaml.ws.transport.http.HttpServletRequestAdapter;
import org.opensaml.ws.transport.http.HttpServletResponseAdapter;
import org.opensaml.xml.XMLObject;
import org.opensaml.xml.parse.BasicParserPool;
import org.opensaml.xml.security.SecurityException;
import org.opensaml.xml.security.x509.KeyStoreX509CredentialAdapter;
import org.opensaml.xml.security.x509.X509Credential;
import org.opensaml.xml.validation.ValidationException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.gv.egovernment.moa.id.config.webgui.exception.ConfigurationException;
import at.gv.egovernment.moa.id.configuration.auth.pvp2.PVP2Utils;

/**
 * @author tlenz
 *
 */
public class SLOBackChannelServlet extends SLOBasicServlet {

	private static final long serialVersionUID = 1481623547633064922L;
	private static final Logger log = LoggerFactory
			.getLogger(SLOBackChannelServlet.class);
	
	/**
	 * @throws ConfigurationException
	 */
	public SLOBackChannelServlet() throws ConfigurationException {
		super();
	}


	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		
		try {
			HTTPSOAP11Decoder soapDecoder = new HTTPSOAP11Decoder(new BasicParserPool());
			
			BasicSOAPMessageContext messageContext = new BasicSOAPMessageContext();
			
//			BasicSAMLMessageContext<SAMLObject, ?, ?> messageContext = 
//					new BasicSAMLMessageContext<SAMLObject, SAMLObject, SAMLObject>();
			
			messageContext.setInboundMessageTransport(new HttpServletRequestAdapter(request));

			//messageContext.setMetadataProvider(getConfig().getMetaDataProvier());
			
			//set trustPolicy
//			BasicSecurityPolicy policy = new BasicSecurityPolicy();
//			policy.getPolicyRules().add(
//					new PVPSOAPRequestSecurityPolicy(
//							PVP2Utils.getTrustEngine(getConfig()),
//							IDPSSODescriptor.DEFAULT_ELEMENT_NAME));		
//			SecurityPolicyResolver resolver = new StaticSecurityPolicyResolver(
//					policy);			
//			messageContext.setSecurityPolicyResolver(resolver);
			
			soapDecoder.decode(messageContext);
		 
			Envelope inboundMessage = (Envelope) messageContext
					.getInboundMessage();
			
			LogoutResponse sloResp = null;
			
			if (inboundMessage.getBody() != null) {		
				List<XMLObject> xmlElemList = inboundMessage.getBody().getUnknownXMLObjects();
						
				if (!xmlElemList.isEmpty() && xmlElemList.get(0) instanceof LogoutRequest) {
					LogoutRequest sloReq = (LogoutRequest) xmlElemList.get(0);
					
					//validate request signature
					PVP2Utils.validateSignature(sloReq, getConfig());
					
					sloResp = processLogOutRequest(sloReq, request);

					KeyStore keyStore = getConfig().getPVP2KeyStore();
					X509Credential authcredential = new KeyStoreX509CredentialAdapter(
							keyStore, 
							getConfig().getPVP2KeystoreAuthRequestKeyAlias(), 
							getConfig().getPVP2KeystoreAuthRequestKeyPassword().toCharArray());
					
					HTTPSOAP11Encoder encoder = new HTTPSOAP11Encoder();
					HttpServletResponseAdapter responseAdapter = new HttpServletResponseAdapter(
							response, true);
					BasicSAMLMessageContext<SAMLObject, SAMLObject, SAMLObject> context = new BasicSAMLMessageContext<SAMLObject, SAMLObject, SAMLObject>();
					context.setOutboundSAMLMessageSigningCredential(authcredential);
					context.setOutboundSAMLMessage(sloResp);
					context.setOutboundMessageTransport(responseAdapter);
					
					encoder.encode(context);
					
				} else {
					log.warn("Received request ist not of type LogOutRequest");
					response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
					return;
					
				}
			}
		
		} catch (MessageDecodingException | SecurityException | NoSuchAlgorithmException | ConfigurationException | ValidationException e) {
			log.error("SLO message processing FAILED." , e);			
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, StringEscapeUtils.escapeHtml(e.getMessage()));
			
		} catch (CertificateException e) {
			log.error("SLO message processing FAILED." , e);
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, StringEscapeUtils.escapeHtml(e.getMessage()));
			
		} catch (KeyStoreException e) {
			log.error("SLO message processing FAILED." , e);
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, StringEscapeUtils.escapeHtml(e.getMessage()));
			
		} catch (MessageEncodingException e) {
			log.error("SLO message processing FAILED." , e);
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, StringEscapeUtils.escapeHtml(e.getMessage()));
			
		}
		
		
		
	}
	
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {		
		response.setStatus(HttpServletResponse.SC_NOT_FOUND);
				
	}
	
}