/*************************************************************************
 *                                                                       *
 *  CERT-CVC: EAC 1.11 Card Verifiable Certificate Library               * 
 *                                                                       *
 *  This software 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 any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.ejbca.cvc;

import java.util.HashMap;

/**
 * Utility for mapping a String of type "SHA1WITHRSA" to our own type OIDFIeld.
 * 
 * @author Keijo Kurkinen, Swedish National Police Board
 * @version $Id: AlgorithmUtil.java 23924 2016-07-15 12:15:26Z anatom $
 */
public class AlgorithmUtil {

    private static HashMap<String, OIDField> algorithmMap = new HashMap<String, OIDField>();
    private static HashMap<String, String> conversionMap = new HashMap<String, String>();

    static {
	algorithmMap.put("SHA1WITHRSA", CVCObjectIdentifiers.id_TA_RSA_v1_5_SHA_1);
	algorithmMap.put("SHA256WITHRSA", CVCObjectIdentifiers.id_TA_RSA_v1_5_SHA_256);
	algorithmMap.put("SHA512WITHRSA", CVCObjectIdentifiers.id_TA_RSA_v1_5_SHA_512);
	algorithmMap.put("SHA1WITHRSAANDMGF1", CVCObjectIdentifiers.id_TA_RSA_PSS_SHA_1);
	algorithmMap.put("SHA256WITHRSAANDMGF1", CVCObjectIdentifiers.id_TA_RSA_PSS_SHA_256);
	algorithmMap.put("SHA512WITHRSAANDMGF1", CVCObjectIdentifiers.id_TA_RSA_PSS_SHA_512);
	// Because CVC certificates does not use standard X9.62 signature encoding we
	// have CVC variants of the ECDSA signature algorithms
	// skip SHA1WITHCVC-ECDSA etc since we have to convert the signature manually to
	// support HSM providers
	algorithmMap.put("SHA1WITHECDSA", CVCObjectIdentifiers.id_TA_ECDSA_SHA_1);
	algorithmMap.put("SHA224WITHECDSA", CVCObjectIdentifiers.id_TA_ECDSA_SHA_224);
	algorithmMap.put("SHA256WITHECDSA", CVCObjectIdentifiers.id_TA_ECDSA_SHA_256);
	algorithmMap.put("SHA384WITHECDSA", CVCObjectIdentifiers.id_TA_ECDSA_SHA_384);
	algorithmMap.put("SHA512WITHECDSA", CVCObjectIdentifiers.id_TA_ECDSA_SHA_512);

    }

    static {
	// Because CVC certificates does not use standard X9.62 signature encoding we
	// have CVC variants of the ECDSA signature algorithms
	// We have these to make it easier for folks by letting them use the regular
	// style algorithm names
	// skip SHA1WITHCVC-ECDSA etc since we have to convert the signature manually to
	// support HSM providers
	conversionMap.put("SHA1WITHECDSA", "SHA1WITHECDSA");
	conversionMap.put("SHA224WITHECDSA", "SHA224WITHECDSA");
	conversionMap.put("SHA256WITHECDSA", "SHA256WITHECDSA");
	conversionMap.put("SHA384WITHECDSA", "SHA384WITHECDSA");
	conversionMap.put("SHA512WITHECDSA", "SHA512WITHECDSA");

    }

    /**
     * Returns the OIDField associated with 'algorithmName'
     * 
     * @param algorithmName
     * @return
     */
    public static OIDField getOIDField(String algorithmName) {
	OIDField oid = algorithmMap.get(convertAlgorithmNameToCVC(algorithmName));
	if (oid == null) {
	    throw new IllegalArgumentException("Unsupported algorithmName: " + algorithmName);
	}
	return oid;
    }

    /**
     * Some (ECDSA) algorithms requires use of particular CVC-ECDSA algorithm names,
     * so we sue this conversion map to translate from regular (SHA1WithECDSA) names
     * to CVC (SHA1WithCVC-ECDSA) names.
     */
    public static String convertAlgorithmNameToCVC(String algorithmName) {
	String name = conversionMap.get(algorithmName.toUpperCase());
	if (name != null) {
	    return name;
	}
	return algorithmName.toUpperCase();
    }

    /**
     * Returns algorithmName for a given OID
     * 
     * @param oid
     * @return
     */
    public static String getAlgorithmName(OIDField oid) {
	for (String key : algorithmMap.keySet()) {
	    OIDField oidfield = algorithmMap.get(key);
	    if (oidfield.getValue().equals(oid.getValue())) {
		return key;
	    }
	}
	throw new IllegalArgumentException("Unknown OIDField: " + oid.getValue());
    }

}