/*
 * 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.security.Principal;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.CredentialsContainer;
import org.springframework.security.core.authority.AuthorityUtils;
import org.springframework.security.core.userdetails.UserDetails;

/**
 * Base class for <code>Authentication</code> objects.
 * <p>
 * Implementations which use this class should be immutable.
 *
 * @author Ben Alex
 * @author Luke Taylor
 */
public abstract class AbstractAuthenticationToken implements Authentication,
		CredentialsContainer {
	// ~ Instance fields
	// ================================================================================================

	private final Collection<GrantedAuthority> authorities;
	private Object details;
	private boolean authenticated = false;

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

	/**
	 * Creates a token with the supplied array of authorities.
	 *
	 * @param authorities the collection of <tt>GrantedAuthority</tt>s for the principal
	 *                    represented by this authentication object.
	 */
	public AbstractAuthenticationToken(Collection<? extends GrantedAuthority> authorities) {
		if (authorities == null) {
			this.authorities = AuthorityUtils.NO_AUTHORITIES;
			return;
		}

		for (GrantedAuthority a : authorities) {
			if (a == null) {
				throw new IllegalArgumentException(
						"Authorities collection cannot contain any null elements");
			}
		}
		ArrayList<GrantedAuthority> temp = new ArrayList<GrantedAuthority>(
				authorities.size());
		temp.addAll(authorities);
		this.authorities = Collections.unmodifiableList(temp);
	}

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

	public Collection<GrantedAuthority> getAuthorities() {
		return authorities;
	}

	public String getName() {
		if (this.getPrincipal() instanceof UserDetails) {
			return ((UserDetails) this.getPrincipal()).getUsername();
		}

		if (getPrincipal() instanceof Principal) {
			return ((Principal) getPrincipal()).getName();
		}

		return (this.getPrincipal() == null) ? "" : this.getPrincipal().toString();
	}

	public boolean isAuthenticated() {
		return authenticated;
	}

	public void setAuthenticated(boolean authenticated) {
		this.authenticated = authenticated;
	}

	public Object getDetails() {
		return details;
	}

	public void setDetails(Object details) {
		this.details = details;
	}

	/**
	 * Checks the {@code credentials}, {@code principal} and {@code details} objects,
	 * invoking the {@code eraseCredentials} method on any which implement
	 * {@link CredentialsContainer}.
	 */
	public void eraseCredentials() {
		eraseSecret(getCredentials());
		eraseSecret(getPrincipal());
		eraseSecret(details);
	}

	private void eraseSecret(Object secret) {
		if (secret instanceof CredentialsContainer) {
			((CredentialsContainer) secret).eraseCredentials();
		}
	}

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

		AbstractAuthenticationToken test = (AbstractAuthenticationToken) obj;

		if (!authorities.equals(test.authorities)) {
			return false;
		}

		if ((this.details == null) && (test.getDetails() != null)) {
			return false;
		}

		if ((this.details != null) && (test.getDetails() == null)) {
			return false;
		}

		if ((this.details != null) && (!this.details.equals(test.getDetails()))) {
			return false;
		}

		if ((this.getCredentials() == null) && (test.getCredentials() != null)) {
			return false;
		}

		if ((this.getCredentials() != null)
				&& !this.getCredentials().equals(test.getCredentials())) {
			return false;
		}

		if (this.getPrincipal() == null && test.getPrincipal() != null) {
			return false;
		}

		if (this.getPrincipal() != null
				&& !this.getPrincipal().equals(test.getPrincipal())) {
			return false;
		}

		return this.isAuthenticated() == test.isAuthenticated();
	}

	@Override
	public int hashCode() {
		int code = 31;

		for (GrantedAuthority authority : authorities) {
			code ^= authority.hashCode();
		}

		if (this.getPrincipal() != null) {
			code ^= this.getPrincipal().hashCode();
		}

		if (this.getCredentials() != null) {
			code ^= this.getCredentials().hashCode();
		}

		if (this.getDetails() != null) {
			code ^= this.getDetails().hashCode();
		}

		if (this.isAuthenticated()) {
			code ^= -37;
		}

		return code;
	}

	@Override
	public String toString() {
		StringBuilder sb = new StringBuilder();
		sb.append(super.toString()).append(": ");
		sb.append("Principal: ").append(this.getPrincipal()).append("; ");
		sb.append("Credentials: [PROTECTED]; ");
		sb.append("Authenticated: ").append(this.isAuthenticated()).append("; ");
		sb.append("Details: ").append(this.getDetails()).append("; ");

		if (!authorities.isEmpty()) {
			sb.append("Granted Authorities: ");

			int i = 0;
			for (GrantedAuthority authority : authorities) {
				if (i++ > 0) {
					sb.append(", ");
				}

				sb.append(authority);
			}
		} else {
			sb.append("Not granted any authorities");
		}

		return sb.toString();
	}
}
