/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.cxf.ws.security.wss4j;

import java.security.Principal;
import java.security.cert.X509Certificate;
import java.util.List;
import java.util.Map;
import java.util.Vector;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.security.auth.callback.CallbackHandler;
import javax.xml.namespace.QName;
import javax.xml.soap.SOAPBody;
import javax.xml.soap.SOAPException;
import javax.xml.soap.SOAPMessage;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.transform.dom.DOMSource;

import org.apache.cxf.binding.soap.SoapFault;
import org.apache.cxf.binding.soap.SoapMessage;
import org.apache.cxf.binding.soap.SoapVersion;
import org.apache.cxf.binding.soap.saaj.SAAJInInterceptor;
import org.apache.cxf.common.i18n.Message;
import org.apache.cxf.common.logging.LogUtils;
import org.apache.cxf.helpers.CastUtils;
import org.apache.cxf.interceptor.Fault;
import org.apache.cxf.phase.Phase;
import org.apache.cxf.security.SecurityContext;
import org.apache.cxf.staxutils.StaxUtils;
import org.apache.ws.security.WSConstants;
import org.apache.ws.security.WSSConfig;
import org.apache.ws.security.WSSecurityEngine;
import org.apache.ws.security.WSSecurityEngineResult;
import org.apache.ws.security.WSSecurityException;
import org.apache.ws.security.handler.RequestData;
import org.apache.ws.security.handler.WSHandlerConstants;
import org.apache.ws.security.handler.WSHandlerResult;
import org.apache.ws.security.message.token.Timestamp;
import org.apache.ws.security.util.WSSecurityUtil;

/**
 * Performs WS-Security inbound actions.
 * 
 * @author <a href="mailto:tsztelak@gmail.com">Tomasz Sztelak</a>
 */
public class WSS4JInInterceptor extends AbstractWSS4JInterceptor {

    public static final String TIMESTAMP_RESULT = "wss4j.timestamp.result";
    public static final String SIGNATURE_RESULT = "wss4j.signature.result";
    public static final String PRINCIPAL_RESULT = "wss4j.principal.result";
    public static final String PROCESSOR_MAP = "wss4j.processor.map";

    private static final Logger LOG = LogUtils.getL7dLogger(WSS4JInInterceptor.class);
    private static final Logger TIME_LOG = LogUtils.getL7dLogger(WSS4JInInterceptor.class,
                                                                 null,
                                                                 WSS4JInInterceptor.class.getName()
                                                                     + "-Time");

    /**
     *
     */
    private WSSecurityEngine secEngineOverride;
    
    public WSS4JInInterceptor() {
        super();

        setPhase(Phase.PRE_PROTOCOL);
        getAfter().add(SAAJInInterceptor.class.getName());
    }

    public WSS4JInInterceptor(Map<String, Object> properties) {
        this();
        setProperties(properties);
        final Map<QName, String> map = CastUtils.cast(
            (Map)properties.get(PROCESSOR_MAP));
        if (map != null) {
            secEngineOverride = createSecurityEngine(map);
        }
    }

    public void handleMessage(SoapMessage msg) throws Fault {
        boolean doDebug = LOG.isLoggable(Level.FINE);
        boolean doTimeLog = TIME_LOG.isLoggable(Level.FINE);

        SoapVersion version = msg.getVersion();
        if (doDebug) {
            LOG.fine("WSS4JInInterceptor: enter handleMessage()");
        }

        long t0 = 0;
        long t1 = 0;
        long t2 = 0;
        long t3 = 0;

        if (doTimeLog) {
            t0 = System.currentTimeMillis();
        }

        RequestData reqData = new RequestData();
        /*
         * The overall try, just to have a finally at the end to perform some
         * housekeeping.
         */
        try {
            reqData.setMsgContext(msg);

            Vector actions = new Vector();
            String action = getAction(msg, version);

            int doAction = WSSecurityUtil.decodeAction(action, actions);

            String actor = (String)getOption(WSHandlerConstants.ACTOR);

            SOAPMessage doc = msg.getContent(SOAPMessage.class);

            if (doc == null) {
                throw new SoapFault(new Message("NO_SAAJ_DOC", LOG), version.getReceiver());
            }

            CallbackHandler cbHandler = getCallback(reqData, doAction);

            /*
             * Get and check the Signature specific parameters first because
             * they may be used for encryption too.
             */
            doReceiverAction(doAction, reqData);
            
            Vector wsResult = null;
            if (doTimeLog) {
                t1 = System.currentTimeMillis();
            }

            wsResult = getSecurityEngine().processSecurityHeader(
                doc.getSOAPPart(), 
                actor, 
                cbHandler, 
                reqData.getSigCrypto(), 
                reqData.getDecCrypto()
            );

            if (doTimeLog) {
                t2 = System.currentTimeMillis();
            }

            if (wsResult == null) { // no security header found
                if (doAction == WSConstants.NO_SECURITY) {
                    return;
                } else if (doc.getSOAPPart().getEnvelope().getBody().hasFault()) {
                    LOG.warning("Request does not contain required Security header, " 
                                + "but it's a fault.");
                    return;
                } else {
                    LOG.warning("Request does not contain required Security header");
                    throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
                }
            }
            if (reqData.getWssConfig().isEnableSignatureConfirmation()) {
                checkSignatureConfirmation(reqData, wsResult);
            }

            /*
             * Now we can check the certificate used to sign the message. In the
             * following implementation the certificate is only trusted if
             * either it itself or the certificate of the issuer is installed in
             * the keystore. Note: the method verifyTrust(X509Certificate)
             * allows custom implementations with other validation algorithms
             * for subclasses.
             */

            // Extract the signature action result from the action vector
            WSSecurityEngineResult actionResult = WSSecurityUtil
                .fetchActionResult(wsResult, WSConstants.SIGN);

            if (actionResult != null) {
                X509Certificate returnCert = (X509Certificate)actionResult
                    .get(WSSecurityEngineResult.TAG_X509_CERTIFICATE);

                if (returnCert != null && !verifyTrust(returnCert, reqData)) {
                    LOG.warning("The certificate used for the signature is not trusted");
                    throw new WSSecurityException(WSSecurityException.FAILED_CHECK);
                }
                msg.put(SIGNATURE_RESULT, actionResult);
            }

            /*
             * Perform further checks on the timestamp that was transmitted in
             * the header. In the following implementation the timestamp is
             * valid if it was created after (now-ttl), where ttl is set on
             * server side, not by the client. Note: the method
             * verifyTimestamp(Timestamp) allows custom implementations with
             * other validation algorithms for subclasses.
             */

            // Extract the timestamp action result from the action vector
            actionResult = WSSecurityUtil.fetchActionResult(wsResult, WSConstants.TS);

            if (actionResult != null) {
                Timestamp timestamp = (Timestamp)actionResult.get(WSSecurityEngineResult.TAG_TIMESTAMP);

                if (timestamp != null && !verifyTimestamp(timestamp, decodeTimeToLive(reqData))) {
                    LOG.warning("The timestamp could not be validated");
                    throw new WSSecurityException(WSSecurityException.MESSAGE_EXPIRED);
                }
                msg.put(TIMESTAMP_RESULT, actionResult);
            }

            /*
             * now check the security actions: do they match, in right order?
             */
            if (!checkReceiverResults(wsResult, actions)) {
                LOG.warning("Security processing failed (actions mismatch)");
                throw new WSSecurityException(WSSecurityException.INVALID_SECURITY);
            }

            doResults(msg, actor, doc, wsResult);

            if (doTimeLog) {
                t3 = System.currentTimeMillis();
                TIME_LOG.fine("Receive request: total= " + (t3 - t0) 
                        + " request preparation= " + (t1 - t0)
                        + " request processing= " + (t2 - t1) 
                        + " header, cert verify, timestamp= " + (t3 - t2) + "\n");
            }

            if (doDebug) {
                LOG.fine("WSS4JInInterceptor: exit handleMessage()");
            }

        } catch (WSSecurityException e) {
            LOG.log(Level.WARNING, "", e);
            SoapFault fault = createSoapFault(version, e);
            throw fault;
        } catch (XMLStreamException e) {
            throw new SoapFault(new Message("STAX_EX", LOG), e, version.getSender());
        } catch (SOAPException e) {
            throw new SoapFault(new Message("SAAJ_EX", LOG), e, version.getSender());
        } finally {
            reqData.clear();
            reqData = null;
        }
    }

    private void doResults(SoapMessage msg, String actor, SOAPMessage doc, Vector wsResult)
        throws SOAPException, XMLStreamException {
        /*
         * All ok up to this point. Now construct and setup the security result
         * structure. The service may fetch this and check it.
         */
        List<Object> results = CastUtils.cast((List)msg.get(WSHandlerConstants.RECV_RESULTS));
        if (results == null) {
            results = new Vector<Object>();
            msg.put(WSHandlerConstants.RECV_RESULTS, results);
        }
        WSHandlerResult rResult = new WSHandlerResult(actor, wsResult);
        results.add(0, rResult);

        SOAPBody body = doc.getSOAPBody();

        XMLStreamReader reader = StaxUtils.createXMLStreamReader(new DOMSource(body));
        // advance just past body
        int evt = reader.next();
        int i = 0;
        while (reader.hasNext() && i < 1
               && (evt != XMLStreamConstants.END_ELEMENT || evt != XMLStreamConstants.START_ELEMENT)) {
            reader.next();
            i++;
        }
        msg.setContent(XMLStreamReader.class, reader);
        
        for (WSSecurityEngineResult o : CastUtils.cast(wsResult, WSSecurityEngineResult.class)) {
            final Principal p = (Principal)o.get(WSSecurityEngineResult.TAG_PRINCIPAL);
            if (p != null) {
                msg.put(PRINCIPAL_RESULT, p);                   
                SecurityContext sc = msg.get(SecurityContext.class);
                if (sc == null || sc.getUserPrincipal() == null) {
                    SecurityContext c = new SecurityContext() {
                        public Principal getUserPrincipal() {
                            return p;
                        }
                        public boolean isUserInRole(String role) {
                            return false;
                        }
                    };
                    msg.put(SecurityContext.class, c);
                    break;
                }
            }            
        }
    }

    private String getAction(SoapMessage msg, SoapVersion version) {
        String action = (String)getOption(WSHandlerConstants.ACTION);
        if (action == null) {
            action = (String)msg.get(WSHandlerConstants.ACTION);
        }
        if (action == null) {
            LOG.warning("No security action was defined!");
            throw new SoapFault("No security action was defined!", version.getReceiver());
        }
        return action;
    }

    private CallbackHandler getCallback(RequestData reqData, int doAction) throws WSSecurityException {
        /*
         * To check a UsernameToken or to decrypt an encrypted message we need a
         * password.
         */
        CallbackHandler cbHandler = null;
        if ((doAction & (WSConstants.ENCR | WSConstants.UT)) != 0) {
            cbHandler = getPasswordCB(reqData);
        }
        return cbHandler;
    }
    
    /**
     * @return      the WSSecurityEngine in use by this interceptor.
     *              This engine is defined to be the secEngineOverride
     *              instance, if defined in this class (and supplied through
     *              construction); otherwise, it is taken to be the default
     *              WSSecEngine instance (currently defined in the WSHandler
     *              base class).
     *
     * TODO the WSHandler base class defines secEngine to be static, which
     * is really bad, because the engine has mutable state on it.
     */
    private WSSecurityEngine
    getSecurityEngine() {
        if (secEngineOverride != null) {
            return secEngineOverride;
        }
        return secEngine;
    }

    /**
     * @return      a freshly minted WSSecurityEngine instance, using the
     *              (non-null) processor map, to be used to initialize the
     *              WSSecurityEngine instance.
     *
     * TODO The WSS4J APIs leave something to be desired here, but hopefully
     * we'll clean all this up in WSS4J-2.0
     */
    private WSSecurityEngine
    createSecurityEngine(
        final Map<QName, String> map
    ) {
        assert map != null;
        final WSSConfig config = WSSConfig.getNewInstance();
        for (Map.Entry<QName, String> entry : map.entrySet()) {
            final QName key = entry.getKey();
            String val = entry.getValue();
            if (val != null) {
                val = val.trim();
                if ("null".equals(val) || val.length() == 0) {
                    val = null;
                }
            }
            config.setProcessor(key, val);
        }
        final WSSecurityEngine ret = new WSSecurityEngine();
        ret.setWssConfig(config);
        return ret;
    }
    
    
    /**
     * Create a SoapFault from a WSSecurityException, following the SOAP Message Security
     * 1.1 specification, chapter 12 "Error Handling".
     * 
     * When the Soap version is 1.1 then set the Fault/Code/Value from the fault code
     * specified in the WSSecurityException (if it exists).
     * 
     * Otherwise set the Fault/Code/Value to env:Sender and the Fault/Code/Subcode/Value
     * as the fault code from the WSSecurityException.
     */
    private SoapFault 
    createSoapFault(SoapVersion version, WSSecurityException e) {
        SoapFault fault;
        javax.xml.namespace.QName faultCode = e.getFaultCode();
        if (version.getVersion() == 1.1 && faultCode != null) {
            fault = new SoapFault(e.getMessage(), e, faultCode);
        } else {
            fault = new SoapFault(e.getMessage(), e, version.getSender());
            if (version.getVersion() != 1.1 && faultCode != null) {
                fault.setSubCode(faultCode);
            }
        }
        return fault;
    }
    
}
