/**
 * DSS - Digital Signature Services
 * Copyright (C) 2015 European Commission, provided under the CEF programme
 *
 * This file is part of the "DSS - Digital Signature Services" project.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package eu.europa.esig.dss.x509;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.security.auth.x500.X500Principal;

import eu.europa.esig.dss.tsl.ServiceInfo;

/**
 * This source of certificates handles any non trusted certificates. (ex: intermediate certificates used in building certification chain)
 */
public class CommonCertificateSource implements CertificateSource {

	/**
	 * This variable represents the certificate pool with all encapsulated certificates
	 */
	protected CertificatePool certPool;
	/**
	 * The list of all encapsulated certificate tokens. It must be <code>null</code> when instantiating.
	 */
	protected List<CertificateToken> certificateTokens;

	/**
	 * The default constructor to generate a certificates source with an independent certificates pool.
	 */
	public CommonCertificateSource() {
		certPool = new CertificatePool();
	}

	/**
	 * The default constructor with mandatory certificates pool.
	 *
	 * @param certPool
	 */
	public CommonCertificateSource(final CertificatePool certPool) {
		if (certPool == null) {
			throw new NullPointerException();
		}
		this.certPool = certPool;
	}

	/**
	 * This method returns the certificate source type associated to the implementation class.
	 *
	 * @return
	 */
	protected CertificateSourceType getCertificateSourceType() {
		return CertificateSourceType.OTHER;
	}

	@Override
	public CertificatePool getCertificatePool() {
		return certPool;
	}

	/**
	 * This method adds an external certificate to the encapsulated pool and to the source. If the certificate is already present in the pool its
	 * source type is associated to the token.
	 *
	 * @param x509Certificate
	 *            the certificate to add
	 * @return the corresponding certificate token
	 */
	@Override
	public CertificateToken addCertificate(final CertificateToken x509Certificate) {
		final CertificateToken certToken = certPool.getInstance(x509Certificate, getCertificateSourceType());
		if (certificateTokens != null) {
			if (!certificateTokens.contains(certToken)) {
				certificateTokens.add(certToken);
			}
		}
		return certToken;
	}

	/**
	 * Retrieves the unmodifiable list of all certificate tokens from this source.
	 *
	 * @return
	 */
	public List<CertificateToken> getCertificates() {
		return Collections.unmodifiableList(certificateTokens);
	}

	/**
	 * This method returns the <code>List</code> of <code>CertificateToken</code>(s) corresponding to the given subject distinguished name.
	 * The content of the encapsulated certificates pool can be different from the content of the source.
	 *
	 * @param x500Principal
	 *            subject distinguished names of the certificate to find
	 * @return If no match is found then an empty list is returned.
	 */
	@Override
	public List<CertificateToken> get(final X500Principal x500Principal) {
		List<CertificateToken> certificateTokenList = null;
		if (x500Principal != null) {
			final List<CertificateToken> missingCertificateTokens = new ArrayList<CertificateToken>();
			certificateTokenList = certPool.get(x500Principal);
			for (final CertificateToken certificateToken : certificateTokenList) {
				if (!certificateTokens.contains(certificateToken)) {
					missingCertificateTokens.add(certificateToken);
				}
			}
			if (missingCertificateTokens.size() > 0) {
				certificateTokenList.removeAll(missingCertificateTokens);
			}
		} else {

			certificateTokenList = new ArrayList<CertificateToken>();
		}
		return Collections.unmodifiableList(certificateTokenList);
	}

	/**
	 * This method is used internally to prevent the addition of a certificate through the <code>CertificatePool</code>.
	 *
	 * @param certificate
	 * @param serviceInfo
	 * @return
	 */
	protected CertificateToken addCertificate(final CertificateToken certificate, final ServiceInfo serviceInfo) {
		final CertificateToken certToken = certPool.getInstance(certificate, getCertificateSourceType(), serviceInfo);
		if (certificateTokens != null) {
			if (!certificateTokens.contains(certToken)) {
				certificateTokens.add(certToken);
			}
		}
		return certToken;
	}

	/**
	 * This method is used internally to remove a certificate from the <code>CertificatePool</code>.
	 *
	 * @param certificate
	 * @return true if removed
	 */
	public boolean removeCertificate(CertificateToken certificate) {
		if (certificateTokens != null) {
			if (certificateTokens.contains(certificate)) {
				return certificateTokens.remove(certificate);
			}
		}
		return false;
	}

	/**
	 * This method is used internally to remove a X500Principal from the <code>CertificatePool</code>.
	 *
	 * @param certificate
	 * @return true if removed
	 */
	public boolean removeX500Principal(X500Principal x500Principal) {
		boolean removed = false;
		if (certificateTokens !=null) {
			List<CertificateToken> listToRemove = get(x500Principal);
			for (CertificateToken certificateToken : listToRemove) {
				removed |= removeCertificate(certificateToken);
			}
		}
		return removed;
	}

}