/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions copyright [year] [name of copyright owner]".
 *
 * Copyright 2013-2015 ForgeRock AS.
 */

package org.forgerock.json.jose.jwt;

/**
 * An Enum for the JWT Header parameter names.
 * <p>
 * As described in the JWT specification, the reserved JWT header parameters are listed,
 * <ul>
 *     <li>"typ"</li>
 *     <li>"alg"</li>
 * </ul>
 * Any other header parameter name is deemed as a "custom" header parameter.
 *
 * @since 2.0.0
 */
public enum JwtHeaderKey {

    /** Type JWT header parameter.. */
    TYP,
    /** Algorithm JWT header parameter. */
    ALG,
    /** Generic header key for a custom header parameter. */
    CUSTOM;

    /**
     * Returns a lowercase String of the JwtHeaderKey constant.
     *
     * @return Lowercase String representation of the constant.
     * @see #toString()
     */
    public String value() {
        return toString();
    }

    /**
     * Gets the JwtHeaderKey constant that matches the given String.
     * <p>
     * If the given String does not match any of the constants, then CUSTOM is returned.
     *
     * @param headerKey The String representation of a JwtHeaderKey.
     * @return The matching JwtHeaderKey.
     */
    public static JwtHeaderKey getHeaderKey(String headerKey) {
        try {
            return JwtHeaderKey.valueOf(headerKey.toUpperCase());
        } catch (IllegalArgumentException e) {
            return CUSTOM;
        }
    }

    /**
     * Turns the JwtHeaderKey constant into a lowercase String.
     *
     * @return {@inheritDoc}
     */
    @Override
    public String toString() {
        return super.toString().toLowerCase();
    }
}
