/*
 * 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
 *
 *      https://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.dao;

import org.springframework.security.authentication.AuthenticationProvider;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.InternalAuthenticationServiceException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsPasswordService;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.crypto.factory.PasswordEncoderFactories;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.util.Assert;

/**
 * An {@link AuthenticationProvider} implementation that retrieves user details from a
 * {@link UserDetailsService}.
 *
 * @author Ben Alex
 * @author Rob Winch
 */
public class DaoAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider {

	/**
	 * The plaintext password used to perform
	 * {@link PasswordEncoder#matches(CharSequence, String)} on when the user is not found
	 * to avoid SEC-2056.
	 */
	private static final String USER_NOT_FOUND_PASSWORD = "userNotFoundPassword";

	private PasswordEncoder passwordEncoder;

	/**
	 * The password used to perform {@link PasswordEncoder#matches(CharSequence, String)}
	 * on when the user is not found to avoid SEC-2056. This is necessary, because some
	 * {@link PasswordEncoder} implementations will short circuit if the password is not
	 * in a valid format.
	 */
	private volatile String userNotFoundEncodedPassword;

	private UserDetailsService userDetailsService;

	private UserDetailsPasswordService userDetailsPasswordService;

	public DaoAuthenticationProvider() {
		this(PasswordEncoderFactories.createDelegatingPasswordEncoder());
	}

	/**
	 * Creates a new instance using the provided {@link PasswordEncoder}
	 * @param passwordEncoder the {@link PasswordEncoder} to use. Cannot be null.
	 * @since 6.0.3
	 */
	public DaoAuthenticationProvider(PasswordEncoder passwordEncoder) {
		setPasswordEncoder(passwordEncoder);
	}

	@Override
	@SuppressWarnings("deprecation")
	protected void additionalAuthenticationChecks(UserDetails userDetails,
			UsernamePasswordAuthenticationToken authentication) throws AuthenticationException {
		if (authentication.getCredentials() == null) {
			this.logger.debug("Failed to authenticate since no credentials provided");
			throw new BadCredentialsException(this.messages
					.getMessage("AbstractUserDetailsAuthenticationProvider.badCredentials", "Bad credentials"));
		}
		String presentedPassword = authentication.getCredentials().toString();
		if (!this.passwordEncoder.matches(presentedPassword, userDetails.getPassword())) {
			this.logger.debug("Failed to authenticate since password does not match stored value");
			throw new BadCredentialsException(this.messages
					.getMessage("AbstractUserDetailsAuthenticationProvider.badCredentials", "Bad credentials"));
		}
	}

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

	@Override
	protected final UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication)
			throws AuthenticationException {
		prepareTimingAttackProtection();
		try {
			UserDetails loadedUser = this.getUserDetailsService().loadUserByUsername(username);
			if (loadedUser == null) {
				throw new InternalAuthenticationServiceException(
						"UserDetailsService returned null, which is an interface contract violation");
			}
			return loadedUser;
		}
		catch (UsernameNotFoundException ex) {
			mitigateAgainstTimingAttack(authentication);
			throw ex;
		}
		catch (InternalAuthenticationServiceException ex) {
			throw ex;
		}
		catch (Exception ex) {
			throw new InternalAuthenticationServiceException(ex.getMessage(), ex);
		}
	}

	@Override
	protected Authentication createSuccessAuthentication(Object principal, Authentication authentication,
			UserDetails user) {
		boolean upgradeEncoding = this.userDetailsPasswordService != null
				&& this.passwordEncoder.upgradeEncoding(user.getPassword());
		if (upgradeEncoding) {
			String presentedPassword = authentication.getCredentials().toString();
			String newPassword = this.passwordEncoder.encode(presentedPassword);
			user = this.userDetailsPasswordService.updatePassword(user, newPassword);
		}
		return super.createSuccessAuthentication(principal, authentication, user);
	}

	private void prepareTimingAttackProtection() {
		if (this.userNotFoundEncodedPassword == null) {
			this.userNotFoundEncodedPassword = this.passwordEncoder.encode(USER_NOT_FOUND_PASSWORD);
		}
	}

	private void mitigateAgainstTimingAttack(UsernamePasswordAuthenticationToken authentication) {
		if (authentication.getCredentials() != null) {
			String presentedPassword = authentication.getCredentials().toString();
			this.passwordEncoder.matches(presentedPassword, this.userNotFoundEncodedPassword);
		}
	}

	/**
	 * Sets the PasswordEncoder instance to be used to encode and validate passwords. If
	 * not set, the password will be compared using
	 * {@link PasswordEncoderFactories#createDelegatingPasswordEncoder()}
	 * @param passwordEncoder must be an instance of one of the {@code PasswordEncoder}
	 * types.
	 */
	public void setPasswordEncoder(PasswordEncoder passwordEncoder) {
		Assert.notNull(passwordEncoder, "passwordEncoder cannot be null");
		this.passwordEncoder = passwordEncoder;
		this.userNotFoundEncodedPassword = null;
	}

	protected PasswordEncoder getPasswordEncoder() {
		return this.passwordEncoder;
	}

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

	protected UserDetailsService getUserDetailsService() {
		return this.userDetailsService;
	}

	public void setUserDetailsPasswordService(UserDetailsPasswordService userDetailsPasswordService) {
		this.userDetailsPasswordService = userDetailsPasswordService;
	}

}
