/* 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.acegisecurity.providers.dao;

import org.acegisecurity.AuthenticationException;
import org.acegisecurity.AuthenticationServiceException;
import org.acegisecurity.BadCredentialsException;

import org.acegisecurity.providers.AuthenticationProvider;
import org.acegisecurity.providers.UsernamePasswordAuthenticationToken;
import org.acegisecurity.providers.encoding.PasswordEncoder;
import org.acegisecurity.providers.encoding.PlaintextPasswordEncoder;

import org.acegisecurity.userdetails.UserDetails;
import org.acegisecurity.userdetails.UserDetailsService;

import org.springframework.dao.DataAccessException;

import org.springframework.util.Assert;


/**
 * An {@link AuthenticationProvider} implementation that retrieves user details from an {@link UserDetailsService}.
 *
 * @author Ben Alex
 * @version $Id$
 */
public class DaoAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider {
    //~ Instance fields ================================================================================================

    private PasswordEncoder passwordEncoder = new PlaintextPasswordEncoder();
    private SaltSource saltSource;
    private UserDetailsService userDetailsService;

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

    protected void additionalAuthenticationChecks(UserDetails userDetails,
        UsernamePasswordAuthenticationToken authentication)
        throws AuthenticationException {
        Object salt = null;

        if (this.saltSource != null) {
            salt = this.saltSource.getSalt(userDetails);
        }

        if (!passwordEncoder.isPasswordValid(userDetails.getPassword(), authentication.getCredentials().toString(), salt)) {
            throw new BadCredentialsException(messages.getMessage(
                    "AbstractUserDetailsAuthenticationProvider.badCredentials", "Bad credentials"), userDetails);
        }
    }

    protected void doAfterPropertiesSet() throws Exception {
        Assert.notNull(this.userDetailsService, "A UserDetailsService must be set");
    }

    public PasswordEncoder getPasswordEncoder() {
        return passwordEncoder;
    }

    public SaltSource getSaltSource() {
        return saltSource;
    }

    public UserDetailsService getUserDetailsService() {
        return userDetailsService;
    }

    protected final UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication)
        throws AuthenticationException {
        UserDetails loadedUser;

        try {
            loadedUser = this.getUserDetailsService().loadUserByUsername(username);
        } catch (DataAccessException repositoryProblem) {
            throw new AuthenticationServiceException(repositoryProblem.getMessage(), repositoryProblem);
        }

        if (loadedUser == null) {
            throw new AuthenticationServiceException(
                "UserDetailsService returned null, which is an interface contract violation");
        }

        return loadedUser;
    }

    /**
     * Sets the PasswordEncoder instance to be used to encode and validate passwords. If not set, {@link
     * PlaintextPasswordEncoder} will be used by default.
     *
     * @param passwordEncoder The passwordEncoder to use
     */
    public void setPasswordEncoder(PasswordEncoder passwordEncoder) {
        this.passwordEncoder = passwordEncoder;
    }

    /**
     * The source of salts to use when decoding passwords. <code>null</code> is a valid value, meaning the
     * <code>DaoAuthenticationProvider</code> will present <code>null</code> to the relevant
     * <code>PasswordEncoder</code>.
     *
     * @param saltSource to use when attempting to decode passwords via the <code>PasswordEncoder</code>
     */
    public void setSaltSource(SaltSource saltSource) {
        this.saltSource = saltSource;
    }

    public void setUserDetailsService(UserDetailsService userDetailsService) {
        this.userDetailsService = userDetailsService;
    }
}
