/**
    * 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.wss4j.common.crypto;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.lang.reflect.Constructor;
  import java.util.Map;
  import java.util.Properties;
  
  import org.apache.wss4j.common.ext.WSSecurityException;
  import org.apache.wss4j.common.util.Loader;
  
  /**
   * CryptoFactory.
   */
  public abstract class CryptoFactory {
      private static final org.slf4j.Logger LOG =
          org.slf4j.LoggerFactory.getLogger(CryptoFactory.class);
  
      /**
       * getInstance
       * <p/>
       * Returns an instance of Crypto. This method uses the file
       * <code>crypto.properties</code> to determine which implementation to
       * use. Thus the property <code>org.apache.wss4j.crypto.provider</code>
       * must define the classname of the Crypto implementation. The file
       * may contain other property definitions as well. These properties are
       * handed over to the Crypto implementation. The file
       * <code>crypto.properties</code> is loaded with the
       * <code>Loader.getResource()</code> method.
       * <p/>
       *
       * @return The crypto implementation was defined
       * @throws WSSecurityException if there is an error in loading the crypto properties
       */
      public static Crypto getInstance() throws WSSecurityException {
          return getInstance("crypto.properties");
      }
  
      /**
       * getInstance
       * <p/>
       * Returns an instance of Crypto. The properties are handed over the the crypto
       * implementation. The properties must at least contain the Crypto implementation
       * class name as the value of the property : org.apache.wss4j.crypto.provider
       * <p/>
       *
       * @param properties      The Properties that are forwarded to the crypto implementation
       *                        and the Crypto impl class name.
       *                        These properties are dependent on the crypto implementation
       * @return The cyrpto implementation or null if no cryptoClassName was defined
       * @throws WSSecurityException if there is an error in loading the crypto properties
       */
      public static Crypto getInstance(Properties properties) throws WSSecurityException {
          if (properties == null) {
              LOG.debug("Cannot load Crypto instance as properties object is null");
              throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE,
                      "empty", new Object[] {"Cannot load Crypto instance as properties object is null"});
          }
          return getInstance(properties, Loader.getClassLoader(CryptoFactory.class), null);
      }
  
      /**
       * getInstance
       * <p/>
       * Returns an instance of Crypto loaded with the given classloader.
       * The properties are handed over the the crypto implementation.
       * The properties must at least contain the Crypto implementation
       * class name as the value of the property : org.apache.wss4j.crypto.provider
       * <p/>
       *
       * @param properties      The Properties that are forwarded to the crypto implementation
       *                        and the Crypto impl class name.
       *                        These properties are dependent on the crypto implementation
       * @param classLoader   The class loader to use
       * @param passwordEncryptor The PasswordEncryptor to use to decrypt encrypted passwords
       * @return The crypto implementation or null if no cryptoClassName was defined
       * @throws WSSecurityException if there is an error in loading the crypto properties
       */
      public static Crypto getInstance(
          Properties properties,
         ClassLoader classLoader,
         PasswordEncryptor passwordEncryptor
     ) throws WSSecurityException {
         if (properties == null) {
             LOG.debug("Cannot load Crypto instance as properties object is null");
             throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE,
                     "empty", new Object[] {"Cannot load Crypto instance as properties object is null"});
         }
 
         String cryptoClassName = properties.getProperty("org.apache.wss4j.crypto.provider");
         if (cryptoClassName == null) {
             cryptoClassName = properties.getProperty("org.apache.ws.security.crypto.provider");
         }
 
         Class<? extends Crypto> cryptoClass = null;
         if (cryptoClassName == null
             || cryptoClassName.equals("org.apache.wss4j.common.crypto.Merlin")
             || cryptoClassName.equals("org.apache.ws.security.components.crypto.Merlin")) {
             try {
                 return new Merlin(properties, classLoader, passwordEncryptor);
             } catch (Exception e) {
                 LOG.debug("Unable to instantiate Merlin", e);
                 throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE, e, "empty",
                                               new Object[] {"Cannot create Crypto class " + cryptoClassName});
             }
         } else {
             try {
                 // instruct the class loader to load the crypto implementation
                 cryptoClass = Loader.loadClass(cryptoClassName, Crypto.class);
             } catch (ClassNotFoundException ex) {
                 LOG.debug(ex.getMessage(), ex);
                 throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE, ex,
                         "empty", new Object[] {cryptoClassName + " Not Found"});
             }
         }
         return loadClass(cryptoClass, properties, classLoader);
     }
 
     /**
      * getInstance
      * <p/>
      * Returns an instance of Crypto. The supplied map is handed over the the crypto
      * implementation. The map can be <code>null</code>. It is dependent on the
      * Crypto implementation how the initialization is done in this case.
      * <p/>
      *
      * @param cryptoClass     This is the crypto implementation class. No default is
      *                        provided here.
      * @param map             The Maps that is forwarded to the crypto implementation.
      *                        These contents of the map are dependent on the
      *                        underlying crypto implementation specified in the
      *                        cryptoClassName parameter.
      * @return The crypto implementation or null if no cryptoClassName was defined
      * @throws WSSecurityException if there is an error in loading the crypto properties
      */
     public static Crypto getInstance(
         Class<? extends Crypto> cryptoClass,
         Map<Object, Object> map
     ) throws WSSecurityException {
         return loadClass(cryptoClass, map, Loader.getClassLoader(CryptoFactory.class));
     }
 
     /**
      * getInstance
      * <p/>
      * Returns an instance of Crypto. This method uses the specified filename
      * to load a property file. This file shall use the property
      * <code>org.apache.wss4j.crypto.provider</code>
      * to define the classname of the Crypto implementation. The file
      * may contain other property definitions as well. These properties are
      * handed over to the Crypto implementation. The specified file
      * is loaded with the <code>Loader.getResource()</code> method.
      * <p/>
      *
      * @param propFilename The name of the property file to load
      * @return The crypto implementation that was defined
      * @throws WSSecurityException if there is an error in loading the crypto properties
      */
     public static Crypto getInstance(String propFilename) throws WSSecurityException {
         return getInstance(propFilename, Loader.getClassLoader(CryptoFactory.class));
     }
 
     public static Crypto getInstance(
         String propFilename,
         ClassLoader customClassLoader
     ) throws WSSecurityException {
         Properties properties = getProperties(propFilename, customClassLoader);
         return getInstance(properties, customClassLoader, null);
     }
 
     /**
      * This allows loading the classes with a custom class loader
      * @param cryptoClass
      * @param map
      * @param loader
      * @throws WSSecurityException if there is an error in loading the crypto properties
      */
     private static Crypto loadClass(
         Class<? extends Crypto> cryptoClass,
         Map<Object, Object> map,
         ClassLoader loader
     ) throws WSSecurityException {
         LOG.debug("Using Crypto Engine [{}]", cryptoClass);
         try {
             Constructor<? extends Crypto> c = null;
             try {
                 Class<?>[] classes = new Class[]{Map.class, ClassLoader.class};
                 c = cryptoClass.getConstructor(classes);
                 return c.newInstance(map, loader);
             } catch (NoSuchMethodException ex) {
                 Class<?>[] classes =
                     new Class[]{Properties.class, Map.class, PasswordEncryptor.class};
                 c = cryptoClass.getConstructor(classes);
                 return c.newInstance(map, loader, null);
             }
         } catch (Exception e) {
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Unable to instantiate: " + cryptoClass.getName(), e);
             }
             throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE, e,
                     "empty", new Object[] {cryptoClass + " cannot create instance"});
         }
     }
 
     /**
      * This allows loading the classes with a custom class loader
      * @param cryptoClass
      * @param map
      * @param loader
      * @throws WSSecurityException if there is an error in loading the crypto properties
      */
     private static Crypto loadClass(
         Class<? extends Crypto> cryptoClass,
         Properties map,
         ClassLoader loader
     ) throws WSSecurityException {
         LOG.debug("Using Crypto Engine [{}]", cryptoClass);
         try {
             Constructor<? extends Crypto> c = null;
             try {
                 Class<?>[] classes = new Class[]{Properties.class, ClassLoader.class};
                 c = cryptoClass.getConstructor(classes);
                 return c.newInstance(map, loader);
             } catch (NoSuchMethodException ex) {
                 Class<?>[] classes =
                     new Class[]{Properties.class, ClassLoader.class, PasswordEncryptor.class};
                 c = cryptoClass.getConstructor(classes);
                 return c.newInstance(map, loader, null);
             }
         } catch (Exception e) {
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Unable to instantiate: " + cryptoClass.getName(), e);
             }
             throw new WSSecurityException(WSSecurityException.ErrorCode.FAILURE, e,
                     "empty", new Object[] {cryptoClass + " cannot create instance"});
         }
     }
 
     /**
      * This allows loading the resources with a custom class loader
      * @param propFilename
      * @param loader
      * @return a Properties object loaded from the propFilename argument
      * @throws WSSecurityException if there is an error in loading the crypto properties
      */
     public static Properties getProperties(
         String propFilename,
         ClassLoader loader
     ) throws WSSecurityException {
         Properties properties = new Properties();
         try (InputStream is = Loader.loadInputStream(loader, propFilename)) {
             if (is == null) {
                 throw new WSSecurityException(
                     WSSecurityException.ErrorCode.FAILURE,
                     "resourceNotFound",
                     new Object[] {propFilename}
                 );
             }
             properties.load(is);
         } catch (IOException e) {
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Cannot find resource: " + propFilename, e);
             }
             throw new WSSecurityException(
                 WSSecurityException.ErrorCode.FAILURE, e,
                 "resourceNotFound", new Object[] {propFilename}
             );
         }
         return properties;
     }
 
 }