/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.ksb.security.admin.service.impl;

 import org.apache.commons.lang.StringUtils;

 import org.bouncycastle.jce.X509Principal;

 import org.bouncycastle.x509.X509V3CertificateGenerator;

 import org.kuali.rice.core.api.config.property.Config;

 import org.kuali.rice.core.api.config.property.ConfigContext;

 import org.kuali.rice.ksb.security.admin.KeyStoreEntryDataContainer;

 import org.kuali.rice.ksb.security.admin.service.JavaSecurityManagementService;

 import org.springframework.beans.factory.InitializingBean;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.IOException;

 import java.security.GeneralSecurityException;

 import java.security.KeyPair;

 import java.security.KeyPairGenerator;

 import java.security.KeyStore;

 import java.security.KeyStoreException;

 import java.security.NoSuchAlgorithmException;

 import java.security.PrivateKey;

 import java.security.Security;

 import java.security.UnrecoverableEntryException;

 import java.security.cert.Certificate;

 import java.util.ArrayList;

 import java.util.Calendar;

 import java.util.Date;

 import java.util.Enumeration;

 import java.util.List;

 /**

  * This is an implementation of the {@link JavaSecurityManagementService} interface used by the KSB module 

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public class JavaSecurityManagementServiceImpl implements JavaSecurityManagementService, InitializingBean {

     protected final String CLIENT_KEY_GENERATOR_ALGORITHM = "RSA";

     protected final String CLIENT_SECURE_RANDOM_ALGORITHM = "SHA1PRNG";

     protected final int CLIENT_KEY_PAIR_KEY_SIZE = 512;

     private final int CLIENT_CERT_EXPIRATION_DAYS = 9999;

     private static final String MODULE_SHA_RSA_ALGORITHM = "SHA1withRSA";

     private static final String MODULE_JKS_TYPE = "JKS";

     private String moduleKeyStoreLocation;

     private String moduleKeyStoreAlias;

     private String moduleKeyStorePassword;

     private KeyStore moduleKeyStore;

     private PrivateKey modulePrivateKey;

     /**

      * Load the module's keystore and private key for this "application"

      */

     public void afterPropertiesSet() throws Exception {

         if (StringUtils.isEmpty(getModuleKeyStoreLocation())) {

             setModuleKeyStoreLocation(ConfigContext.getCurrentContextConfig().getKeystoreFile());

         }

         if (StringUtils.isEmpty(getModuleKeyStoreAlias())) {

             setModuleKeyStoreAlias(ConfigContext.getCurrentContextConfig().getKeystoreAlias());

         }

         if (StringUtils.isEmpty(getModuleKeyStorePassword())) {

             setModuleKeyStorePassword(ConfigContext.getCurrentContextConfig().getKeystorePassword());

         }

         verifyConfiguration();

         this.moduleKeyStore = loadKeyStore();

         this.modulePrivateKey = loadPrivateKey();

     }

     /**

      * Verifies the configuration of this service and throws an exception if it is not configured properly.

      */

     protected void verifyConfiguration() {

         if (StringUtils.isEmpty(getModuleKeyStoreLocation())) {

             throw new RuntimeException("Value for configuration parameter '" + Config.KEYSTORE_FILE + "' could not be found.  Please ensure that the keystore is configured properly.");

         }

         if (StringUtils.isEmpty(getModuleKeyStoreAlias())) {

             throw new RuntimeException("Value for configuration parameter '" + Config.KEYSTORE_ALIAS + "' could not be found.  Please ensure that the keystore is configured properly.");

         }

         if (StringUtils.isEmpty(getModuleKeyStorePassword())) {

             throw new RuntimeException("Value for configuration parameter '" + Config.KEYSTORE_PASSWORD + "' could not be found.  Please ensure that the keystore is configured properly.");

         }

         File keystoreFile = new File(getModuleKeyStoreLocation());

         if (!keystoreFile.exists()) {

             throw new RuntimeException("Value for configuration parameter '" + Config.KEYSTORE_FILE + "' is invalid.  The file does not exist on the filesystem, location was: '" + getModuleKeyStoreLocation() + "'");

         }

         if (!keystoreFile.canRead()) {

             throw new RuntimeException("Value for configuration parameter '" + Config.KEYSTORE_FILE + "' is invalid.  The file exists but is not readable (please check permissions), location was: '" + getModuleKeyStoreLocation() + "'");

         }

     }

     protected KeyStore loadKeyStore() throws GeneralSecurityException, IOException {

         KeyStore keyStore = KeyStore.getInstance(getModuleKeyStoreType());

         FileInputStream stream = null;

         try {

             stream = new FileInputStream(getModuleKeyStoreLocation());

             keyStore.load(stream, getModuleKeyStorePassword().toCharArray());

             stream.close();

         } catch (Exception e) {

             if (stream != null) {

                 try {

                     stream.close();

                 } catch (Exception ignored) {

                 }

             }

         }

         return keyStore;

     }

     protected PrivateKey loadPrivateKey() throws GeneralSecurityException {

         return (PrivateKey)getModuleKeyStore().getKey(getModuleKeyStoreAlias(), getModuleKeyStorePassword().toCharArray());

     }

     public void removeClientCertificate(String alias) throws KeyStoreException {

         KeyStore moduleKeyStore = getModuleKeyStore();

         if (!moduleKeyStore.entryInstanceOf(alias, KeyStore.TrustedCertificateEntry.class)) {

             throw new RuntimeException("Only entries of type " + KeyStoreEntryDataContainer.DISPLAYABLE_ENTRY_TYPES.get(KeyStore.TrustedCertificateEntry.class) + " can be removed");

         }

         getModuleKeyStore().deleteEntry(alias);

     }

     protected void addClientCertificateToModuleKeyStore(String alias, Certificate clientCertificate) throws KeyStoreException {

         getModuleKeyStore().setEntry(alias, new KeyStore.TrustedCertificateEntry(clientCertificate), null);

     }

     public boolean isAliasInKeystore(String alias) throws KeyStoreException {

         return getModuleKeyStore().containsAlias(alias);

     }

     public String getCertificateAlias(Certificate certificate) throws KeyStoreException {

         return getModuleKeyStore().getCertificateAlias(certificate);

     }

     public KeyStore generateClientKeystore(String alias, String clientPassphrase) throws GeneralSecurityException {

         if (isAliasInKeystore(alias)) {

             throw new KeyStoreException("Alias '" + alias + "' already exists in module keystore");

         }

 //        Certificate[] clientCertificateChain = {};

 //        PrivateKey clientPrivateKey = null;

         KeyStore ks = null;

         try {

             // generate a key pair for the client

             KeyPairGenerator keyGen = KeyPairGenerator.getInstance(CLIENT_KEY_GENERATOR_ALGORITHM);

 //            SecureRandom random = SecureRandom.getInstance(CLIENT_SECURE_RANDOM_ALGORITHM);

             keyGen.initialize(CLIENT_KEY_PAIR_KEY_SIZE);

 //            keyGen.initialize(new RSAKeyGenParameterSpec(512,RSAKeyGenParameterSpec.F0));

             KeyPair pair = keyGen.generateKeyPair();

 //            PublicKey clientPublicKey = pair.getPublic();

 //            clientPrivateKey = pair.getPrivate();

 //            // generate the Certificate

 //            X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();

 ////            X509Name nameInfo = new X509Name(false,"CN=" + alias);

 //            certificateGenerator.setSignatureAlgorithm("MD5WithRSA");

 //            certificateGenerator.setSerialNumber(new java.math.BigInteger("1"));

 //            X509Principal nameInfo = new X509Principal("CN=" + alias);

 //            certificateGenerator.setIssuerDN(nameInfo);

 //            certificateGenerator.setSubjectDN(nameInfo);                       // note: same as issuer

 //            certificateGenerator.setNotBefore(new Date());

 //            Calendar c = Calendar.getInstance();

 //            c.add(Calendar.DATE, CLIENT_CERT_EXPIRATION_DAYS);

 //            certificateGenerator.setNotAfter(c.getTime());

 //            certificateGenerator.setPublicKey(clientPublicKey);

 //            X509Certificate cert = certificateGenerator.generateX509Certificate(clientPrivateKey);

 //            clientCertificateChain = new Certificate[]{cert};

 //

 //            // generate client keyStore file

 //            ks = KeyStore.getInstance(getModuleKeyStoreType());

 //            ks.load(null, clientPassphrase.toCharArray());

 //            // set client private key on keyStore file

 //            ks.setEntry(alias, new KeyStore.PrivateKeyEntry(clientPrivateKey, clientCertificateChain), new KeyStore.PasswordProtection(clientPassphrase.toCharArray()));

             Certificate cert = generateCertificate(pair, alias);

             ks = generateKeyStore(cert, pair.getPrivate(), alias, clientPassphrase);

             // set the module certificate on the client keyStore file

             ks.setEntry(getModuleKeyStoreAlias(), new KeyStore.TrustedCertificateEntry(getCertificate(getModuleKeyStoreAlias())),  null);

             // add the client certificate to the module keyStore

             addClientCertificateToModuleKeyStore(alias, cert);

             return ks;

         } catch (IOException e) {

             throw new RuntimeException("Could not create new KeyStore",e);

         }

     }

     protected Certificate generateCertificate(KeyPair keyPair, String alias) throws GeneralSecurityException {

       //test that Bouncy Castle provider is present and add it if it's not

       if( Security.getProvider(org.bouncycastle.jce.provider.BouncyCastleProvider.PROVIDER_NAME) == null) {

               Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

       }

       X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();

 //      X509Name nameInfo = new X509Name(false,"CN=" + alias);

       certificateGenerator.setSignatureAlgorithm("MD5WithRSA");

       certificateGenerator.setSerialNumber(new java.math.BigInteger("1"));

       X509Principal nameInfo = new X509Principal("CN=" + alias);

       certificateGenerator.setIssuerDN(nameInfo);

       certificateGenerator.setSubjectDN(nameInfo);  // note: same as issuer for self signed

       certificateGenerator.setNotBefore(new Date());

       Calendar c = Calendar.getInstance();

       c.add(Calendar.DATE, CLIENT_CERT_EXPIRATION_DAYS);

       certificateGenerator.setNotAfter(c.getTime());

       certificateGenerator.setPublicKey(keyPair.getPublic());

       return certificateGenerator.generate(keyPair.getPrivate(), org.bouncycastle.jce.provider.BouncyCastleProvider.PROVIDER_NAME);

     }

     protected KeyStore generateKeyStore(Certificate cert, PrivateKey privateKey, String alias, String keyStorePassword) throws GeneralSecurityException, IOException {

         KeyStore ks = KeyStore.getInstance(getModuleKeyStoreType());

         ks.load(null, keyStorePassword.toCharArray());

         // set client private key on keyStore file

         ks.setEntry(alias, new KeyStore.PrivateKeyEntry(privateKey, new Certificate[]{cert}), new KeyStore.PasswordProtection(keyStorePassword.toCharArray()));

         return ks;

     }

     public List<KeyStoreEntryDataContainer> getListOfModuleKeyStoreEntries() {

         List<KeyStoreEntryDataContainer> keyStoreEntries = new ArrayList<KeyStoreEntryDataContainer>();

         try {

             KeyStore moduleKeyStore = getModuleKeyStore();

             // List the aliases

             for (Enumeration<String> enumer = moduleKeyStore.aliases(); enumer.hasMoreElements();) {

                 String alias = (String) enumer.nextElement();

                 KeyStoreEntryDataContainer dataContainer = new KeyStoreEntryDataContainer(alias,moduleKeyStore.getCreationDate(alias));

                 KeyStore.PasswordProtection passwordProtection = null;

                 if (moduleKeyStore.isKeyEntry(alias)) {

                     passwordProtection = new KeyStore.PasswordProtection(getModuleKeyStorePassword().toCharArray());

                 }

                 KeyStore.Entry entry = moduleKeyStore.getEntry(alias, passwordProtection);

                 dataContainer.setType(entry.getClass());

                 keyStoreEntries.add(dataContainer);

             }

         } catch (KeyStoreException e) {

             e.printStackTrace();

             throw new RuntimeException(e);

         } catch (NoSuchAlgorithmException e) {

             e.printStackTrace();

             throw new RuntimeException(e);

         } catch (UnrecoverableEntryException e) {

             e.printStackTrace();

             throw new RuntimeException(e);

         }

         return keyStoreEntries;

     }

     public String getModuleSignatureAlgorithm() {

         return getModuleAlgorithm();

     }

     /**

      * @see java.security.KeyStore#getCertificate(java.lang.String)

      */

     public Certificate getCertificate(String alias) throws KeyStoreException {

         return getModuleKeyStore().getCertificate(alias);

     }

     protected String getModuleKeyStoreType() {

         return MODULE_JKS_TYPE;

     }

     protected String getModuleAlgorithm() {

         return MODULE_SHA_RSA_ALGORITHM;

     }

     public String getModuleKeyStoreLocation() {

         return this.moduleKeyStoreLocation;

     }

     public void setModuleKeyStoreLocation(String moduleKeyStoreLocation) {

         this.moduleKeyStoreLocation = moduleKeyStoreLocation;

     }

     public String getModuleKeyStoreAlias() {

         return this.moduleKeyStoreAlias;

     }

     public void setModuleKeyStoreAlias(String moduleKeyStoreAlias) {

         this.moduleKeyStoreAlias = moduleKeyStoreAlias;

     }

     public String getModuleKeyStorePassword() {

         return this.moduleKeyStorePassword;

     }

     public void setModuleKeyStorePassword(String moduleKeyStorePassword) {

         this.moduleKeyStorePassword = moduleKeyStorePassword;

     }

     public KeyStore getModuleKeyStore() {

         return this.moduleKeyStore;

     }

     public PrivateKey getModulePrivateKey() {

         return this.modulePrivateKey;

     }

 }