/*******************************************************************************
 * Copyright 2014 Federal Chancellery Austria
 * MOA-ID has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
package at.gv.egovernment.moa.id.protocols.pvp2x.signer;

import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.interfaces.RSAPrivateKey;

import org.opensaml.xml.security.credential.Credential;
import org.opensaml.xml.security.credential.UsageType;
import org.opensaml.xml.security.x509.BasicX509Credential;
import org.opensaml.xml.security.x509.KeyStoreX509CredentialAdapter;
import org.opensaml.xml.security.x509.X509Credential;
import org.opensaml.xml.signature.Signature;
import org.opensaml.xml.signature.SignatureConstants;

import at.gv.egovernment.moa.id.opemsaml.MOAKeyStoreX509CredentialAdapter;
import at.gv.egovernment.moa.id.protocols.pvp2x.config.PVPConfiguration;
import at.gv.egovernment.moa.id.protocols.pvp2x.utils.SAML2Utils;
import at.gv.egovernment.moa.logging.Logger;
import at.gv.egovernment.moa.util.KeyStoreUtils;
import at.gv.egovernment.moa.util.MiscUtil;

public class CredentialProvider {
	
	private static KeyStore keyStore = null;
	
	public static X509Credential getIDPMetaDataSigningCredential()
			throws CredentialsNotAvailableException {
		PVPConfiguration config = PVPConfiguration.getInstance();
		try {
			
			if (keyStore == null)
				keyStore = KeyStoreUtils.loadKeyStore(config.getIDPKeyStoreFilename(), 
						config.getIDPKeyStorePassword());

			MOAKeyStoreX509CredentialAdapter credentials = new MOAKeyStoreX509CredentialAdapter(
					keyStore, config.getIDPKeyAliasMetadata(), config
							.getIDPKeyPasswordMetadata().toCharArray());

			credentials.setUsageType(UsageType.SIGNING);
			if (credentials.getPrivateKey() == null && credentials.getSecretKey() == null) {
				Logger.error("IDP Metadata Signing credentials is not found or contains no PrivateKey.");
				throw new CredentialsNotAvailableException("IDP Assertion Signing credentials (Alias: "
						+ config.getIDPKeyAliasMetadata() + ") is not found or contains no PrivateKey.", null);
				
			}
			return credentials;
		} catch (Exception e) {
			Logger.error("Failed to generate IDP Metadata Signing credentials");
			e.printStackTrace();
			throw new CredentialsNotAvailableException(e.getMessage(), null);
		}
	}

	public static X509Credential getIDPAssertionSigningCredential()
			throws CredentialsNotAvailableException {
		PVPConfiguration config = PVPConfiguration.getInstance();
		try {
			if (keyStore == null)
				keyStore = KeyStoreUtils.loadKeyStore(config.getIDPKeyStoreFilename(), 
						config.getIDPKeyStorePassword());

			MOAKeyStoreX509CredentialAdapter credentials = new MOAKeyStoreX509CredentialAdapter(
					keyStore, config.getIDPKeyAliasAssertionSign(), config
							.getIDPKeyPasswordAssertionSign().toCharArray());
			
			credentials.setUsageType(UsageType.SIGNING);
			if (credentials.getPrivateKey() == null && credentials.getSecretKey() == null) {
				Logger.error("IDP Assertion Signing credentials is not found or contains no PrivateKey.");
				throw new CredentialsNotAvailableException("IDP Assertion Signing credentials (Alias: "
						+ config.getIDPKeyAliasAssertionSign() + ") is not found or contains no PrivateKey.", null);
				
			}
			
			return (X509Credential) credentials;
		} catch (Exception e) {
			Logger.error("Failed to generate IDP Assertion Signing credentials");
			e.printStackTrace();
			throw new CredentialsNotAvailableException(e.getMessage(), null);
		}
	}
	
	public static X509Credential getIDPAssertionEncryptionCredential()
			throws CredentialsNotAvailableException {
		PVPConfiguration config = PVPConfiguration.getInstance();
		try {
			if (keyStore == null)
				keyStore = KeyStoreUtils.loadKeyStore(config.getIDPKeyStoreFilename(), 
						config.getIDPKeyStorePassword());

			//if no encryption key is configured return null
			if (MiscUtil.isEmpty(config.getIDPKeyAliasAssertionEncryption()))
				return null;
			
			MOAKeyStoreX509CredentialAdapter credentials = new MOAKeyStoreX509CredentialAdapter(
					keyStore, config.getIDPKeyAliasAssertionEncryption(), config
							.getIDPKeyPasswordAssertionEncryption().toCharArray());
			
			credentials.setUsageType(UsageType.ENCRYPTION);
			
			if (credentials.getPrivateKey() == null && credentials.getSecretKey() == null) {
				Logger.error("IDP Assertion Encryption credentials is not found or contains no PrivateKey.");
				throw new CredentialsNotAvailableException("IDP Assertion Encryption credentials (Alias: "
						+ config.getIDPKeyAliasAssertionEncryption() + ") is not found or contains no PrivateKey.", null);
				
			}
			
			return (X509Credential) credentials;
		} catch (Exception e) {
			Logger.error("Failed to generate IDP Assertion Encryption credentials");
			e.printStackTrace();
			throw new CredentialsNotAvailableException(e.getMessage(), null);
		}
	}
	
	public static Signature getIDPSignature(Credential credentials) {
		
		PrivateKey privatekey = credentials.getPrivateKey();
		
		Signature signer = SAML2Utils.createSAMLObject(Signature.class);
		
		if (privatekey instanceof RSAPrivateKey) {
			signer.setSignatureAlgorithm(SignatureConstants.ALGO_ID_SIGNATURE_RSA_SHA256);
			
		} else if (privatekey instanceof iaik.security.ecc.ecdsa.ECPrivateKey) {
			signer.setSignatureAlgorithm(SignatureConstants.ALGO_ID_SIGNATURE_ECDSA_SHA1);

		} else {
			Logger.warn("Could NOT evaluate the Private-Key type from PVP credential.");
			
		}

		signer.setCanonicalizationAlgorithm(SignatureConstants.ALGO_ID_C14N_EXCL_OMIT_COMMENTS);		
		signer.setSigningCredential(credentials);
		return signer;
		
	}

	public static Credential getSPTrustedCredential(String entityID)
			throws CredentialsNotAvailableException {

		iaik.x509.X509Certificate cert = PVPConfiguration.getInstance()
				.getTrustEntityCertificate(entityID);
		
		if (cert == null) {
			throw new CredentialsNotAvailableException("ServiceProvider Certificate can not be loaded from Database", null);
		}
		
		BasicX509Credential credential = new BasicX509Credential();
		credential.setEntityId(entityID);
		credential.setUsageType(UsageType.SIGNING);
		credential.setPublicKey(cert.getPublicKey());

		return credential;
	}
	/*
	 * public static Credential getTrustedCredential() throws
	 * CredentialsNotAvailableException { String filename =
	 * PVPConfiguration.getInstance().getTrustEntityCertificate("sp.crt");
	 * 
	 * iaik.x509.X509Certificate cert; try { cert = new X509Certificate(new
	 * FileInputStream(new File(filename))); } catch (CertificateException e) {
	 * e.printStackTrace(); throw new
	 * CredentialsNotAvailableException(e.getMessage(), null); } catch
	 * (FileNotFoundException e) { e.printStackTrace(); throw new
	 * CredentialsNotAvailableException(e.getMessage(), null); } catch
	 * (IOException e) { e.printStackTrace(); throw new
	 * CredentialsNotAvailableException(e.getMessage(), null); }
	 * 
	 * BasicX509Credential credential = new BasicX509Credential();
	 * credential.setEntityId("sp.crt");
	 * credential.setUsageType(UsageType.SIGNING);
	 * credential.setPublicKey(cert.getPublicKey());
	 * 
	 * return credential; }
	 */
}