/*
 * Copyright (c) 2011 Lockheed Martin Corporation
 *
 * 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.eurekastreams.server.action.principal;

import org.apache.commons.logging.Log;
import org.eurekastreams.commons.actions.context.DefaultPrincipal;
import org.eurekastreams.commons.actions.context.Principal;
import org.eurekastreams.commons.actions.context.PrincipalPopulator;
import org.eurekastreams.commons.logging.LogFactory;
import org.eurekastreams.server.persistence.mappers.cache.Transformer;
import org.eurekastreams.server.service.security.userdetails.ExtendedUserDetails;
import org.springframework.security.Authentication;
import org.springframework.security.context.SecurityContext;
import org.springframework.security.context.SecurityContextHolder;
import org.springframework.security.userdetails.UserDetails;

/**
 * Create/return Principal from Spring security context if present, return null if not.
 */
public class SpringSecurityContextPrincipalPopulatorAllowNull implements PrincipalPopulator,
        Transformer<Object, Principal>
{

    /**
     * Local logger instance.
     */
    private final Log logger = LogFactory.make();

    /**
     * Retrieve the {@link Principal} object based on the security context loaded by Spring.
     * 
     * 
     * {@inheritDoc}.
     */
    @Override
    public Principal getPrincipal(final String inAccountId, final String inSessionId)
    {
        Principal currentPrincipal = null;
        try
        {
            UserDetails user = null;

            SecurityContext securityCtx = SecurityContextHolder.getContext();
            if (securityCtx == null)
            {
                return null;
            }

            Authentication auth = securityCtx.getAuthentication();
            if (auth == null)
            {
                return null;
            }

            Object obj = auth.getPrincipal();
            if (obj instanceof UserDetails)
            {
                user = (UserDetails) obj;
            }
            else
            {
                return null;
            }

            ExtendedUserDetails extUser = (ExtendedUserDetails) user;
            currentPrincipal = new DefaultPrincipal(extUser.getUsername(), extUser.getPerson().getOpenSocialId(),
                    extUser.getPerson().getId(), inSessionId);
        }
        catch (Exception ex)
        {
            logger.info("Unable to populate principal from SecurityContext.", ex);
        }
        return currentPrincipal;
    }

    /**
     * Return principal. This implementation ingnores params and returns principal based on Spring SecurityContext, or
     * null if SecurityContext is not populated.
     * 
     * @param inTransformType
     *            Ignored.
     * 
     * @return Principal from Spring security context if present, return null if not.
     */
    @Override
    public Principal transform(final Object inTransformType)
    {
        return getPrincipal(null, "");
    }
}