/**
 * <copyright> Copyright 2006 by Know-Center, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria 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.
 *
 * $Id: SignatureTypes.java,v 1.5 2006/10/31 08:18:56 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.sig;


public class SignatureTypes
{

	/**
	 * Defines all supported states for {@link SignatureTypes} (signature profiles). Signature types can be enabled
	 * ("on"), can be set to support signature only ("sign_only"), to verification only ("verify_only") or can be
	 * disabled ("off" or any other value not covered by other enum values).
	 * 
	 * @author Datentechnik Innovation GmbH
	 */
	public enum State {
		
		/**
		 * Enables a signature profile.
		 */
		ON ("on", "yes", "true", "enabled"),
		
		/**
		 * Disables a signature profile.
		 */
		OFF (),
		
		/**
		 * Restricts the signature profile so that is can only be used for verification purposes and not for signature.
		 */
		VERIFY_ONLY ("verify_only", "verify-only", "verifyonly", "verify only", "verify"),
		
		/**
		 * Allows the signature profile to be used for signature but not for verification. 
		 */
		SIGN_ONLY ("sign_only", "sign-only", "signonly", "sign only", "sign");
		
		/**
		 * Sets the default state when no valid value was provided.
		 */
		private static final State DEFAULT = OFF;
		
		/**
		 * States that allow signatures.
		 */
		private static final State[] CAN_SIGN = { ON, SIGN_ONLY };
		
		/**
		 * States that allow verification.
		 */
		private static final State[] CAN_VERIFY = { ON, VERIFY_ONLY };
		
		private String[] keyWords;

		private State(String... keyWords) {
			this.keyWords = keyWords;
		}
		
		/**
		 * Returns a valid State from a given {@code keyWord}. If the {@code keyWord} cannot be matched to a certain
		 * state, the default State {@link #OFF} is returned.
		 * 
		 * @param keyWord
		 *            A valid keyword like "on", "sign_only"...
		 * @return The enum State.
		 */
		public static State fromString(String keyWord) {
			if (keyWord == null) {
				return DEFAULT;
			}
			try {
				return valueOf(keyWord.toUpperCase());
			} catch (IllegalArgumentException e) {
				for (State candidate : values()) {
					for (String candidateKeyWord : candidate.keyWords) {
						if (keyWord.equalsIgnoreCase(candidateKeyWord)) {
							return candidate;
						}
					}
				}
				return DEFAULT;
			}
		}
		
		/**
		 * Returns {@code true} when the current state is one of the given candidate {@code states}.
		 * 
		 * @param states
		 *            The candidate states.
		 * @return {@code true} when the current state is one of the given candidate states, {@code false} if not.
		 */
		public boolean in(State... states) {
			if (states != null) {
				for (State state : states) {
					if (this == state) {
						return true;
					}
				}
			}
			return false;
		}
		
		/**
		 * Returns if the respective state allows signatures.
		 * @return {@code true} if signatures are allowed, {@code false} if not.
		 */
		public boolean canSign() {
			return in(CAN_SIGN);
		}
		
		/**
		 * Returns if the respective state allows verification.
		 * @return {@code true} if verification is allowed, {@code false} if not.
		 */
		public boolean canVerify() {
			return in(CAN_VERIFY);
		}

	}

}