/**
 * This file Copyright (c) 2013 Magnolia International
 * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
 *
 *
 * This file is dual-licensed under both the Magnolia
 * Network Agreement and the GNU General Public License.
 * You may elect to use one or the other of these licenses.
 *
 * This file is distributed in the hope that it will be
 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
 * Redistribution, except as permitted by whichever of the GPL
 * or MNA you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or
 * modify this file under the terms of the GNU General
 * Public License, Version 3, as published by the Free Software
 * Foundation.  You should have received a copy of the GNU
 * General Public License, Version 3 along with this program;
 * if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 2. For the Magnolia Network Agreement (MNA), this file
 * and the accompanying materials are made available under the
 * terms of the MNA which accompanies this distribution, and
 * is available at http://www.magnolia-cms.com/mna.html
 *
 * Any modifications to this file must keep this entire header
 * intact.
 *
 */
package info.magnolia.blossom.sample.module.support;

import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.bind.ServletRequestDataBinder;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
import org.springframework.web.servlet.support.RequestContextUtils;

/**
 * Enables use of flash attributes in Spring 3.1.x MVC.
 *
 * @see org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#invokeHandlerMethod(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, org.springframework.web.method.HandlerMethod)
 */
public class FlashMapEnabledAnnotationMethodHandlerAdapter extends AnnotationMethodHandlerAdapter {

    /**
     * Overrides attributes being bound to enable lookup of flash attributes. There's no way to populate the model with
     * flash attributes so this hook is called after a new instance has been created and replaces it.
     *
     * NOTE that this will override anything being bound, not just model attributes so be sure to use unique names
     */
    @Override
    protected ServletRequestDataBinder createBinder(HttpServletRequest request, Object target, String objectName) throws Exception {

        Map<String, ?> inputFlashMap = RequestContextUtils.getInputFlashMap(request);
        if (inputFlashMap != null) {
            return super.createBinder(request, inputFlashMap.get(objectName), objectName);
        }

        return super.createBinder(request, target, objectName);
    }

    @Override
    protected ModelAndView invokeHandlerMethod(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        ModelAndView mav = super.invokeHandlerMethod(request, response, handler);

        RedirectAttributes redirectAttributes = (RedirectAttributes) request.getAttribute(RedirectAttributesWebArgumentResolver.REDIRECT_ATTRIBUTES_ATTRIBUTE);
        if (redirectAttributes != null) {
            RequestContextUtils.getOutputFlashMap(request).putAll(redirectAttributes.getFlashAttributes());
        }

        return mav;
    }
}