package com.yihu.base.security.rbas.provider;

import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.InternalAuthenticationServiceException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider;
import org.springframework.security.authentication.dao.SaltSource;
import org.springframework.security.authentication.encoding.PasswordEncoder;
import org.springframework.security.authentication.encoding.PlaintextPasswordEncoder;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.util.Assert;

/**
 * Created by 刘文彬 on 2018/6/1.
 */
public class UserNamePasswordAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider {
    // ~ Static fields/initializers
    // =====================================================================================

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

    // ~ Instance fields
    // ================================================================================================

    private PasswordEncoder passwordEncoder;

    /**
     * The password used to perform
     * {@link PasswordEncoder#isPasswordValid(String, String, Object)} 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 String userNotFoundEncodedPassword;

    private SaltSource saltSource;

    private UserDetailsService userDetailsService;

    public UserNamePasswordAuthenticationProvider() {
        setPasswordEncoder(new PlaintextPasswordEncoder());
    }

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

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

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

        if (authentication.getCredentials() == null) {
            logger.debug("Authentication failed: no credentials provided");

            throw new BadCredentialsException(messages.getMessage(
                    "AbstractUserDetailsAuthenticationProvider.badCredentials",
                    "Bad credentials"));
        }

        String presentedPassword = authentication.getCredentials().toString();

        if (!passwordEncoder.isPasswordValid(userDetails.getPassword(),
                presentedPassword, salt)) {
            logger.debug("Authentication failed: password does not match stored value");

            throw new BadCredentialsException(messages.getMessage(
                    "AbstractUserDetailsAuthenticationProvider.badCredentials",
                    "Bad credentials"));
        }
    }

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

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

        try {
            loadedUser = this.getUserDetailsService().loadUserByUsername(username);
        }
        catch (UsernameNotFoundException notFound) {
//            if (authentication.getCredentials() != null) {
//                String presentedPassword = authentication.getCredentials().toString();
//                passwordEncoder.isPasswordValid(userNotFoundEncodedPassword,
//                        presentedPassword, null);
//            }
            throw notFound;
        }
        catch (Exception repositoryProblem) {
            throw new InternalAuthenticationServiceException(
                    repositoryProblem.getMessage(), repositoryProblem);
        }

        if (loadedUser == null) {
            throw new InternalAuthenticationServiceException(
                    "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, the password will be compared as plain text.
     * <p>
     * For systems which are already using salted password which are encoded with a
     * previous release, the encoder should be of type
     * {@code org.springframework.security.authentication.encoding.PasswordEncoder}.
     * Otherwise, the recommended approach is to use
     * {@code org.springframework.security.crypto.password.PasswordEncoder}.
     *
     * @param passwordEncoder must be an instance of one of the {@code PasswordEncoder}
     * types.
     */
    public void setPasswordEncoder(Object passwordEncoder) {
        Assert.notNull(passwordEncoder, "passwordEncoder cannot be null");

        if (passwordEncoder instanceof PasswordEncoder) {
            setPasswordEncoder((PasswordEncoder) passwordEncoder);
            return;
        }

        if (passwordEncoder instanceof org.springframework.security.crypto.password.PasswordEncoder) {
            final org.springframework.security.crypto.password.PasswordEncoder delegate = (org.springframework.security.crypto.password.PasswordEncoder) passwordEncoder;
            setPasswordEncoder(new PasswordEncoder() {
                public String encodePassword(String rawPass, Object salt) {
                    checkSalt(salt);
                    return delegate.encode(rawPass);
                }

                public boolean isPasswordValid(String encPass, String rawPass, Object salt) {
                    checkSalt(salt);
                    return delegate.matches(rawPass, encPass);
                }

                private void checkSalt(Object salt) {
                    Assert.isNull(salt,
                            "Salt value must be null when used with crypto module PasswordEncoder");
                }
            });

            return;
        }

        throw new IllegalArgumentException(
                "passwordEncoder must be a PasswordEncoder instance");
    }

    private void setPasswordEncoder(PasswordEncoder passwordEncoder) {
        Assert.notNull(passwordEncoder, "passwordEncoder cannot be null");

        this.userNotFoundEncodedPassword = passwordEncoder.encodePassword(
                USER_NOT_FOUND_PASSWORD, null);
        this.passwordEncoder = passwordEncoder;
    }

    protected PasswordEncoder getPasswordEncoder() {
        return 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>.
     * <p>
     * Instead, it is recommended that you use an encoder which uses a random salt and
     * combines it with the password field. This is the default approach taken in the
     * {@code org.springframework.security.crypto.password} package.
     *
     * @param saltSource to use when attempting to decode passwords via the
     * <code>PasswordEncoder</code>
     */
    public void setSaltSource(SaltSource saltSource) {
        this.saltSource = saltSource;
    }

    protected SaltSource getSaltSource() {
        return saltSource;
    }

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

    @Override
    public boolean supports(Class<?> authentication) {
        return true;
    }

    protected UserDetailsService getUserDetailsService() {
        return userDetailsService;
    }
}