/*
 *
 * Copyright (c) 2013 - 2017 Lijun Liao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 *
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * THE AUTHOR LIJUN LIAO. LIJUN LIAO DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the XiPKI software without
 * disclosing the source code of your own applications.
 *
 * For more information, please contact Lijun Liao at this
 * address: lijun.liao@gmail.com
 */

package org.xipki.commons.security;

import java.security.NoSuchAlgorithmException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.xipki.commons.common.util.ParamUtil;
import org.xipki.commons.security.util.AlgorithmUtil;

/**
 * @author Lijun Liao
 * @since 2.1.0
 */

public class CollectionAlgorithmValidator implements AlgorithmValidator {

    private final Set<String> algoNames;

    /**
     * constructor.
     * @param algoNames algorithm names that can be accepted. <code>null</code> or empty to accept
     *            all algorithms
     * @throws NoSuchAlgorithmException if any algoName is unknown.
     */
    public CollectionAlgorithmValidator(Set<String> algoNames) throws NoSuchAlgorithmException {
        Set<String> canonicalizedNames = new HashSet<>();
        if (algoNames != null) {
            for (String m : algoNames) {
                canonicalizedNames.add(AlgorithmUtil.canonicalizeSignatureAlgo(m));
            }
        }
        this.algoNames = Collections.unmodifiableSet(canonicalizedNames);
    }

    public Set<String> getAlgoNames() {
        return algoNames;
    }

    @Override
    public boolean isAlgorithmPermitted(AlgorithmIdentifier algId) {
        ParamUtil.requireNonNull("algId", algId);

        if (algoNames.isEmpty()) {
            return true;
        }

        String name;
        try {
            name = AlgorithmUtil.getSignatureAlgoName(algId);
        } catch (NoSuchAlgorithmException ex) {
            return false;
        }

        return algoNames.contains(name);
    }

    @Override
    public boolean isAlgorithmPermitted(String algoName) {
        ParamUtil.requireNonBlank("algoName", algoName);

        if (algoNames.isEmpty()) {
            return true;
        }

        if (algoNames.contains(algoName)) {
            return true;
        }

        String name;
        try {
            name = AlgorithmUtil.canonicalizeSignatureAlgo(algoName);
        } catch (NoSuchAlgorithmException ex) {
            return false;
        }

        return algoNames.contains(name);
    }

}