/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.usergrid.rest.security.shiro.session;


import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;

import org.apache.shiro.authz.AuthorizationException;
import org.apache.shiro.session.Session;
import org.apache.shiro.session.SessionException;
import org.apache.shiro.session.mgt.SessionContext;
import org.apache.shiro.session.mgt.SessionKey;
import org.apache.shiro.web.session.mgt.WebSessionManager;
import org.apache.shiro.web.util.WebUtils;


/**
 * Intended to keep session request-scoped and therefore not persist them across multiple requests - a user must login
 * on each request. This necessarily means that a mechanism like form-based authentication isn't viable, but the
 * intention is primarily for uses in stateless apis.
 */
public class HttpRequestSessionManager implements WebSessionManager {

    static final String REQUEST_ATTRIBUTE_KEY = "__SHIRO_REQUEST_SESSION";


    @Override
    public Session start( SessionContext context ) throws AuthorizationException {
        if ( !WebUtils.isHttp( context ) ) {
            String msg = "SessionContext must be an HTTP compatible implementation.";
            throw new IllegalArgumentException( msg );
        }

        HttpServletRequest request = WebUtils.getHttpRequest( context );

        String host = getHost( context );

        Session session = createSession( request, host );
        request.setAttribute( REQUEST_ATTRIBUTE_KEY, session );

        return session;
    }


    @Override
    public Session getSession( SessionKey key ) throws SessionException {
        if ( !WebUtils.isHttp( key ) ) {
            String msg = "SessionKey must be an HTTP compatible implementation.";
            throw new IllegalArgumentException( msg );
        }

        HttpServletRequest request = WebUtils.getHttpRequest( key );

        return ( Session ) request.getAttribute( REQUEST_ATTRIBUTE_KEY );
    }


    private String getHost( SessionContext context ) {
        String host = context.getHost();
        if ( host == null ) {
            ServletRequest request = WebUtils.getRequest( context );
            if ( request != null ) {
                host = request.getRemoteHost();
            }
        }
        return host;
    }


    protected Session createSession( HttpServletRequest request, String host ) {
        return new HttpServletRequestSession( request, host );
    }

    @Override
    public boolean isServletContainerSessions() {
        return false;
    }
}