package org.apache.fulcrum.jce.crypto.extended;
   
   /*
    * 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.
   */
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.security.GeneralSecurityException;
  import java.security.Key;
  import java.security.NoSuchAlgorithmException;
  import java.security.SecureRandom;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import javax.crypto.Cipher;
  
  import org.apache.fulcrum.jce.crypto.PasswordFactory;
  import org.apache.fulcrum.jce.crypto.StreamUtil;
  import org.apache.fulcrum.jce.crypto.algo.CryptoStreamGCMImpl;
  import org.apache.fulcrum.jce.crypto.algo.CryptoStreamPBEImpl;
  import org.apache.fulcrum.jce.crypto.extended.CryptoParametersJ8.TYPES;
  
  /**
   * Concrete factory for creating encrypting/decrypting streams. 
   * 
   * 
   **/
  public abstract class CryptoStreamFactoryJ8Template /*  extends CryptoStreamFactoryImpl*/ implements CryptoStreamFactoryJ8
  {
  	
  	/** the salt for the algorithm */
      protected byte[] salt;
  
      /** the count parameter for the algorithm, not used for GCM */
      protected int count;
  
      /** the name of the JCE provider */
      protected String providerName;
  
      /** the algorithm to use */
      protected String algorithm;
      
      private TYPES type;
      
      public TYPES getType() {
        return type;
      }
      
      public void setType(TYPES type) {
      	this.type = type;
      }
      
      /**
       * The JCE provider name known to work. If the value
       * is set to null an appropriate provider will be
       * used.
       */
      protected static final String PROVIDERNAME = null;
  
      protected static final int SALT_SIZE = 16; //might increase cipher length
  
      /** the default instances */
      protected static final Map<TYPES,CryptoStreamFactoryJ8Template> instances = new ConcurrentHashMap<>();
      
      //protected AlgorithmParameters algorithmParameters;// used only for debugging
     
      public CryptoStreamFactoryJ8Template() {
         
      }
      
      /**
       * Factory method to get a default instance
       * 
       * creating instance of type {@link CryptoParametersJ8#DEFAULT_TYPE}.
       * 
       * @return an instance of the CryptoStreamFactory
       */
      public static CryptoStreamFactoryJ8 getInstance() 
      {
          synchronized (CryptoStreamFactoryJ8Template.class) {
              if( !instances.containsKey(CryptoParametersJ8.DEFAULT_TYPE) )
             {
                 try {
                     instances.put(CryptoParametersJ8.DEFAULT_TYPE, 
                             (CryptoParametersJ8.DEFAULT_TYPE.equals(TYPES.PBE))? new CryptoStreamPBEImpl():
                                 new CryptoStreamGCMImpl()
                             );
                 } catch (GeneralSecurityException e) {
                     e.printStackTrace();
                     throw new RuntimeException(e.getMessage());
                 }
             }
     
             return instances.get(CryptoParametersJ8.DEFAULT_TYPE);
         }
     }
 
     /**
      * Factory method to get a default instance
      * 
      * @param type the @see {@link TYPES} of the instance.
      * @return an instance of the CryptoStreamFactory
      */
     public static CryptoStreamFactoryJ8 getInstance(TYPES type) 
     {
         synchronized (CryptoStreamFactoryJ8Template.class) {
             if( !instances.containsKey(type) )
             {
                 try {
                     instances.put(type, 
                             (type.equals(TYPES.PBE))? new CryptoStreamPBEImpl():
                                 new CryptoStreamGCMImpl()
                             );
                 } catch (GeneralSecurityException e) {
                     e.printStackTrace();
                     throw new RuntimeException(e.getMessage());
                 }
             }
     
             return instances.get(type);
         }
     }
     
     /**
      * Factory method to get a default instance
      * 
      * @param type the @see {@link TYPES} of the instance.
      * @param salt provided salt
      * @param count provided count, used only for {@link TYPES#PBE}.
      * @return an instance of the CryptoStreamFactory
      */
     public static CryptoStreamFactoryJ8 getInstance(TYPES type, byte[] salt, int count) 
     {
         synchronized (CryptoStreamFactoryJ8Template.class) {
             if( !instances.containsKey(type) )
             {
                 try {
                     instances.put(type, 
                             (type.equals(TYPES.PBE))? new CryptoStreamPBEImpl(salt, count):
                                 new CryptoStreamGCMImpl(salt)
                             );
                 } catch (Exception e) {
                     e.printStackTrace();
                     throw new RuntimeException(e.getMessage());
                 }
             }
     
             return instances.get(type);
         }
     }
 
 
     /**
      * @see org.apache.fulcrum.jce.crypto.CryptoStreamFactory#getSmartInputStream(java.io.InputStream)
      */
 
     public InputStream getSmartInputStream(InputStream is)
         throws GeneralSecurityException, IOException
     {
         return this.getSmartInputStream(
             is,
             PasswordFactory.getInstance("SHA-256").create()
             );
     }
 
     /**
      * @see org.apache.fulcrum.jce.crypto.CryptoStreamFactory#getInputStream(java.io.InputStream,char[])
      */
     public InputStream getInputStream( InputStream is, char[] password )
         throws GeneralSecurityException, IOException
     {
         byte[] decrypted =  this.createCipher( is, Cipher.DECRYPT_MODE, password.clone() );
         InputStream eis = new ByteArrayInputStream(decrypted);
         return eis;
     }
 
     /**
      * @see org.apache.fulcrum.jce.crypto.extended.CryptoStreamFactoryJ8#getOutputStream(InputStream, OutputStream, char[])
      */
     public OutputStream getOutputStream(InputStream is, OutputStream os, char[] password)
             throws GeneralSecurityException, IOException {
         byte[] encrypted =  this.createCipher( is, Cipher.ENCRYPT_MODE, password.clone() );
         InputStream eis = new ByteArrayInputStream(encrypted);
         StreamUtil.copy(eis, os);
         return os;
     }
     
     /**
      * resets the default instances
      */
     public static void resetInstances()
     {
         CryptoStreamFactoryJ8Template.instances.clear();
     }
     
 //    /**
 //     * Set the default instances from an external application.
 //     * @param instances the new default instances map
 //     * @throws Exception if instances are null
 //     */
 //    public static void setInstances(Map<TYPES,CryptoStreamFactoryJ8Template> instances ) throws Exception
 //    {
 //    	if (instances == null) throw new Exception("setting instances to null not allowed!");
 //        CryptoStreamFactoryJ8Template.instances = instances;
 //    }
     
     /** not used / implemented methods **/
     
     @Override
 	public InputStream getInputStream(InputStream is, String decryptionMode)
 			throws GeneralSecurityException, IOException {
 		throw new UnsupportedOperationException("not implemented");
 	}
 
 	@Override
 	public InputStream getInputStream(InputStream is, String decryptionMode, char[] password)
 			throws GeneralSecurityException, IOException {
 		throw new UnsupportedOperationException("not implemented");
 	}
 
 	@Override
 	public InputStream getInputStream(InputStream is) throws GeneralSecurityException, IOException {
 		throw new UnsupportedOperationException("not implemented");
 	}
 
 	@Override
 	public InputStream getSmartInputStream(InputStream is, char[] password)
 			throws GeneralSecurityException, IOException {
 		throw new UnsupportedOperationException("not implemented");
 	}
 
 	@Override
 	public OutputStream getOutputStream(OutputStream os) throws GeneralSecurityException, IOException {
 		throw new UnsupportedOperationException("not implemented");
 	}
 
 	@Override
 	public OutputStream getOutputStream(OutputStream os, char[] password) throws GeneralSecurityException, IOException {
 		throw new UnsupportedOperationException("not implemented");
 	}
     /** not used methods end **/
 
     /**
      * Create a PBE key.
      *
      * @param password the password to use.
      * @param salt if provided this is used, otherweise {@link #getSalt()}.
      * @return the key
      * @throws GeneralSecurityException creating the key failed
      */
     protected abstract Key createKey( char[] password, byte[] salt ) 
             throws GeneralSecurityException;
 
     /**
      * Create a Cipher.
      *
      * @param is the input stream
      * @param mode the cipher mode
      * @param password the password
      * @return an instance of a cipher
      * @return the cipher as byte array
      * @throws GeneralSecurityException creating a cipher failed
      * @throws IOException creating a cipher failed
      */
     protected abstract byte[] createCipher(InputStream is, int mode, char[] password )
         throws GeneralSecurityException, IOException;
     
     /**
      * creates salt from {@link SecureRandom#getInstance(String)} by default was algorithm SHA1PRNG
      * 
      * changed to {@link SecureRandom#getInstanceStrong()} and let the system decide, what PRNG to use for salt random.
      * 
      * salt size is by default @link {@value #SALT_SIZE}.
      * 
      * @return the generated salt as byte array
      * @throws GeneralSecurityException if no algo could be found.
      */
     protected static byte[] generateSalt() throws GeneralSecurityException {
         SecureRandom random;
         try {
             random = SecureRandom.getInstanceStrong();
             byte[] salt = new byte[SALT_SIZE ];
             random.nextBytes(salt);
             return salt;
         } catch (NoSuchAlgorithmException e) {
             throw new GeneralSecurityException(e);  
         }
     }
 
 	public byte[] getSalt() {
 		return salt.clone();
 	}
 
 	protected void setSalt(byte[] salt) {
 		this.salt = salt.clone();
 	}
 
 	public int getCount() {
 		return count;
 	}
 
 	public void setCount(int count) {
 		this.count = count;
 	}
 
 	public String getProviderName() {
 		return providerName;
 	}
 
 	public void setProviderName(String providerName) {
 		this.providerName = providerName;
 	}
 
 	public String getAlgorithm() {
 		return algorithm;
 	}
 
 	public void setAlgorithm(String algorithm) {
 		this.algorithm = algorithm;
 	}
 
 }