// 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 com.cloud.bridge.auth.ec2;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.axiom.soap.SOAPEnvelope;
import org.apache.axis2.AxisFault;
import org.apache.axis2.context.MessageContext;
import org.apache.axis2.description.HandlerDescription;
import org.apache.axis2.description.Parameter;
import org.apache.axis2.engine.Handler;
import org.apache.commons.codec.binary.Base64;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import com.cloud.bridge.model.UserCredentialsVO;
import com.cloud.bridge.persist.dao.UserCredentialsDao;
import com.cloud.bridge.persist.dao.UserCredentialsDaoImpl;
import com.cloud.bridge.service.UserContext;
import com.cloud.bridge.util.AuthenticationUtils;

public class AuthenticationHandler implements Handler {
    protected final static Logger logger = Logger.getLogger(AuthenticationHandler.class);
    private DocumentBuilderFactory dbf = null;

    protected HandlerDescription handlerDesc = new HandlerDescription("EC2AuthenticationHandler");
    private String name = "EC2AuthenticationHandler";

    @Override
    public void init(HandlerDescription handlerdesc) {
        dbf = DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);

        this.handlerDesc = handlerdesc;
    }

    @Override
    public String getName() {
        return name;
    }

    @Override
    public String toString() {
        return (name != null) ? name.toString() : null;
    }

    @Override
    public HandlerDescription getHandlerDesc() {
        return handlerDesc;
    }

    @Override
    public Parameter getParameter(String name) {
        return handlerDesc.getParameter(name);
    }

    /**
     * For EC2 SOAP calls this function's goal is to extract the X509 certificate that is
     * part of the WS-Security wrapped SOAP request.   We need the cert in order to
     * map it to the user's Cloud API key and Cloud Secret Key.
     */
    @Override
    public InvocationResponse invoke(MessageContext msgContext) throws AxisFault {
        // -> the certificate we want is embedded into the soap header
        try {
            SOAPEnvelope soapEnvelope = msgContext.getEnvelope();
            String xmlHeader = soapEnvelope.toString();
            //System.out.println( "entire request: " + xmlHeader );

            InputStream is = new ByteArrayInputStream(xmlHeader.getBytes("UTF-8"));
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document request = db.parse(is);
            NodeList certs = request.getElementsByTagNameNS("http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd", "BinarySecurityToken");
            if (0 < certs.getLength()) {
                Node item = certs.item(0);
                String result = new String(item.getFirstChild().getNodeValue());
                byte[] certBytes = Base64.decodeBase64(result.getBytes());

                Certificate userCert = null;
                CertificateFactory cf = CertificateFactory.getInstance("X.509");
                ByteArrayInputStream bs = new ByteArrayInputStream(certBytes);
                while (bs.available() > 0)
                    userCert = cf.generateCertificate(bs);
                //System.out.println( "cert: " + userCert.toString());
                String uniqueId = AuthenticationUtils.X509CertUniqueId(userCert);
                logger.debug("X509 cert's uniqueId: " + uniqueId);

                // -> find the Cloud API key and the secret key from the cert's uniqueId
                UserCredentialsDao ucDao = new UserCredentialsDaoImpl();
                UserCredentialsVO cloudKeys = ucDao.getByCertUniqueId(uniqueId);
                if (null == cloudKeys) {
                    logger.error("Cert does not map to Cloud API keys: " + uniqueId);
                    throw new AxisFault("User not properly registered: Certificate does not map to Cloud API Keys", "Client.Blocked");
                } else
                    UserContext.current().initContext(cloudKeys.getAccessKey(), cloudKeys.getSecretKey(), cloudKeys.getAccessKey(), "SOAP Request", null);
                //System.out.println( "end of cert match: " + UserContext.current().getSecretKey());
            }
        } catch (AxisFault e) {
            throw e;
        } catch (Exception e) {
            logger.error("EC2 Authentication Handler: ", e);
            throw new AxisFault("An unknown error occurred.", "Server.InternalError");
        }
        return InvocationResponse.CONTINUE;
    }

    public void revoke(MessageContext msgContext) {
        logger.info(msgContext.getEnvelope().toString());
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public void cleanup() {
    }

    @Override
    public void flowComplete(MessageContext arg0) {
    }
}