/*
 * Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.security.authentication;

import java.io.Serializable;
import java.util.Collection;

import org.springframework.security.core.GrantedAuthority;
import org.springframework.util.Assert;

/**
 * Represents an anonymous <code>Authentication</code>.
 *
 * @author Ben Alex
 */
public class AnonymousAuthenticationToken extends AbstractAuthenticationToken implements
		Serializable {
	// ~ Instance fields
	// ================================================================================================

	private static final long serialVersionUID = 1L;
	private final Object principal;
	private final int keyHash;

	// ~ Constructors
	// ===================================================================================================

	/**
	 * Constructor.
	 *
	 * @param key         to identify if this object made by an authorised client
	 * @param principal   the principal (typically a <code>UserDetails</code>)
	 * @param authorities the authorities granted to the principal
	 * @throws IllegalArgumentException if a <code>null</code> was passed
	 */
	public AnonymousAuthenticationToken(String key, Object principal,
										Collection<? extends GrantedAuthority> authorities) {
		this(extractKeyHash(key), principal, authorities);
	}

	/**
	 * Constructor helps in Jackson Deserialization
	 *
	 * @param keyHash     hashCode of provided Key, constructed by above constructor
	 * @param principal   the principal (typically a <code>UserDetails</code>)
	 * @param authorities the authorities granted to the principal
	 * @since 4.2
	 */
	private AnonymousAuthenticationToken(Integer keyHash, Object principal,
										Collection<? extends GrantedAuthority> authorities) {
		super(authorities);

		if (principal == null || "".equals(principal)) {
			throw new IllegalArgumentException("principal cannot be null or empty");
		}
		Assert.notEmpty(authorities, "authorities cannot be null or empty");

		this.keyHash = keyHash;
		this.principal = principal;
		setAuthenticated(true);
	}

	// ~ Methods
	// ========================================================================================================

	private static Integer extractKeyHash(String key) {
		Assert.hasLength(key, "key cannot be empty or null");
		return key.hashCode();
	}

	@Override
	public boolean equals(Object obj) {
		if (!super.equals(obj)) {
			return false;
		}

		if (obj instanceof AnonymousAuthenticationToken) {
			AnonymousAuthenticationToken test = (AnonymousAuthenticationToken) obj;

			if (this.getKeyHash() != test.getKeyHash()) {
				return false;
			}

			return true;
		}

		return false;
	}

	@Override
	public int hashCode() {
		int result = super.hashCode();
		result = 31 * result + this.keyHash;
		return result;
	}

	/**
	 * Always returns an empty <code>String</code>
	 *
	 * @return an empty String
	 */
	@Override
	public Object getCredentials() {
		return "";
	}

	public int getKeyHash() {
		return this.keyHash;
	}

	@Override
	public Object getPrincipal() {
		return this.principal;
	}
}
