/**
 * 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.rs.security.xml;

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.cert.X509Certificate;
import java.security.spec.MGF1ParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.spec.OAEPParameterSpec;
import javax.crypto.spec.PSource;

import org.apache.wss4j.common.ext.WSSecurityException;
import org.apache.wss4j.common.util.KeyUtils;
import org.apache.xml.security.algorithms.JCEMapper;
import org.apache.xml.security.encryption.XMLCipher;
import org.apache.xml.security.encryption.XMLEncryptionException;
import org.apache.xml.security.utils.EncryptionConstants;

public final class EncryptionUtils {
    private EncryptionUtils() {
        
    }
    
    public static Cipher initCipherWithCert(String keyEncAlgo, int mode, X509Certificate cert)
        throws WSSecurityException {
        return initCipherWithCert(keyEncAlgo, null, mode, cert);
    }
    
    public static Cipher initCipherWithCert(
        String keyEncAlgo, 
        String digestAlg,
        int mode, 
        X509Certificate cert
    ) throws WSSecurityException {
        Cipher cipher = KeyUtils.getCipherInstance(keyEncAlgo);
        try {
            OAEPParameterSpec oaepParameters = 
                constructOAEPParameters(
                    keyEncAlgo, digestAlg, null, null
                );
            if (oaepParameters == null) {
                cipher.init(mode, cert);
            } else {
                cipher.init(mode, cert.getPublicKey(), oaepParameters);
            }
        } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
            throw new WSSecurityException(
                WSSecurityException.ErrorCode.FAILED_ENCRYPTION, e
            );
        }
        return cipher;
    }
    
    public static Cipher initCipherWithKey(String keyEncAlgo, int mode, Key key)
        throws WSSecurityException {
        return initCipherWithKey(keyEncAlgo, null, mode, key);
    }
    
    public static Cipher initCipherWithKey(String keyEncAlgo, String digestAlgo, int mode, Key key)
        throws WSSecurityException {
        Cipher cipher = KeyUtils.getCipherInstance(keyEncAlgo);
        try {
            OAEPParameterSpec oaepParameters = 
                constructOAEPParameters(
                    keyEncAlgo, digestAlgo, null, null
                );
            if (oaepParameters == null) {
                cipher.init(mode, key);
            } else {
                cipher.init(mode, key, oaepParameters);
            }
        } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
            throw new WSSecurityException(
                WSSecurityException.ErrorCode.FAILED_ENCRYPTION, e
            );
        }
        return cipher;
    }
    
    /**
     * Construct an OAEPParameterSpec object from the given parameters
     */
    public static OAEPParameterSpec constructOAEPParameters(
        String encryptionAlgorithm,
        String digestAlgorithm,
        String mgfAlgorithm,
        byte[] oaepParams
    ) {
        if (XMLCipher.RSA_OAEP.equals(encryptionAlgorithm)
            || XMLCipher.RSA_OAEP_11.equals(encryptionAlgorithm)) {
            
            String jceDigestAlgorithm = "SHA-1";
            if (digestAlgorithm != null) {
                jceDigestAlgorithm = JCEMapper.translateURItoJCEID(digestAlgorithm);
            }
            
            PSource.PSpecified pSource = PSource.PSpecified.DEFAULT;
            if (oaepParams != null) {
                pSource = new PSource.PSpecified(oaepParams);
            }
            
            MGF1ParameterSpec mgfParameterSpec = new MGF1ParameterSpec("SHA-1");
            if (XMLCipher.RSA_OAEP_11.equals(encryptionAlgorithm)) {
                if (EncryptionConstants.MGF1_SHA256.equals(mgfAlgorithm)) {
                    mgfParameterSpec = new MGF1ParameterSpec("SHA-256");
                } else if (EncryptionConstants.MGF1_SHA384.equals(mgfAlgorithm)) {
                    mgfParameterSpec = new MGF1ParameterSpec("SHA-384");
                } else if (EncryptionConstants.MGF1_SHA512.equals(mgfAlgorithm)) {
                    mgfParameterSpec = new MGF1ParameterSpec("SHA-512");
                }
            }
            return new OAEPParameterSpec(jceDigestAlgorithm, "MGF1", mgfParameterSpec, pSource);
        }
        
        return null;
    }
    
    public static XMLCipher initXMLCipher(String symEncAlgo, int mode, Key key) 
        throws WSSecurityException {
        try {
            XMLCipher cipher = XMLCipher.getInstance(symEncAlgo);
            cipher.setSecureValidation(true);
            cipher.init(mode, key);
            return cipher;
        } catch (XMLEncryptionException ex) {
            throw new WSSecurityException(WSSecurityException.ErrorCode.UNSUPPORTED_ALGORITHM, ex);
        }
    }
    
}

