/*
 * $Id$
 *
 * 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.struts2.dispatcher;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.struts2.dispatcher.mapper.ActionMapper;
import org.apache.struts2.dispatcher.mapper.ActionMapping;
import org.apache.struts2.views.util.UrlHelper;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.config.entities.ResultConfig;
import com.opensymphony.xwork2.inject.Inject;

/**
 * <!-- START SNIPPET: description -->
 *
 * This result uses the {@link ActionMapper} provided by the {@link ActionMapperFactory} to redirect the browser to a
 * URL that invokes the specified action and (optional) namespace. This is better than the {@link ServletRedirectResult}
 * because it does not require you to encode the URL patterns processed by the {@link ActionMapper} in to your struts.xml
 * configuration files. This means you can change your URL patterns at any point and your application will still work.
 * It is strongly recommended that if you are redirecting to another action, you use this result rather than the
 * standard redirect result.
 *
 * <p/>
 *
 * See examples below for an example of how request parameters could be passed in.
 *
 * <!-- END SNIPPET: description -->
 *
 * <b>This result type takes the following parameters:</b>
 *
 * <!-- START SNIPPET: params -->
 *
 * <ul>
 *
 * <li><b>actionName (default)</b> - the name of the action that will be redirect to</li>
 *
 * <li><b>namespace</b> - used to determine which namespace the action is in that we're redirecting to . If namespace is
 * null, this defaults to the current namespace</li>
 *
 * </ul>
 *
 * <!-- END SNIPPET: params -->
 *
 * <b>Example:</b>
 *
 * <pre><!-- START SNIPPET: example -->
 * &lt;package name="public" extends="struts-default"&gt;
 *     &lt;action name="login" class="..."&gt;
 *         &lt;!-- Redirect to another namespace --&gt;
 *         &lt;result type="redirect-action"&gt;
 *             &lt;param name="actionName"&gt;dashboard&lt;/param&gt;
 *             &lt;param name="namespace"&gt;/secure&lt;/param&gt;
 *         &lt;/result&gt;
 *     &lt;/action&gt;
 * &lt;/package&gt;
 *
 * &lt;package name="secure" extends="struts-default" namespace="/secure"&gt;
 *     &lt;-- Redirect to an action in the same namespace --&gt;
 *     &lt;action name="dashboard" class="..."&gt;
 *         &lt;result&gt;dashboard.jsp&lt;/result&gt;
 *         &lt;result name="error" type="redirect-action&gt;error&lt;/result&gt;
 *     &lt;/action&gt;
 *
 *     &lt;action name="error" class="..."&gt;
 *         &lt;result&gt;error.jsp&lt;/result&gt;
 *     &lt;/action&gt;
 * &lt;/package&gt;
 *
 * &lt;package name="passingRequestParameters" extends="struts-default" namespace="/passingRequestParameters"&gt;
 *    &lt;-- Pass parameters (reportType, width and height) --&gt;
 *    &lt;!--
 *    The redirect-action url generated will be :
 *    /genReport/generateReport.action?reportType=pie&width=100&height=100
 *    --&gt;
 *    &lt;action name="gatherReportInfo" class="..."&gt;
 *       &lt;result name="showReportResult" type="redirect-action"&gt;
 *          &lt;param name="actionName"&gt;generateReport&lt;/param&gt;
 *          &lt;param name="namespace"&gt;/genReport&lt;/param&gt;
 *          &lt;param name="reportType"&gt;pie&lt;/param&gt;
 *          &lt;param name="width"&gt;100&lt;/param&gt;
 *          &lt;param name="height"&gt;100&lt;/param&gt;
 *       &lt;/result&gt;
 *    &lt;/action&gt;
 * &lt;/package&gt;
 *
 *
 * <!-- END SNIPPET: example --></pre>
 *
 * @see ActionMapper
 */
public class ServletActionRedirectResult extends ServletRedirectResult {

    private static final long serialVersionUID = -9042425229314584066L;

    /** The default parameter */
    public static final String DEFAULT_PARAM = "actionName";

    protected String actionName;
    protected String namespace;
    protected String method;

    private Map<String, String> requestParameters = new LinkedHashMap<String, String>();

    public ServletActionRedirectResult() {
        super();
    }

    public ServletActionRedirectResult(String actionName) {
        this(null, actionName, null);
    }

    public ServletActionRedirectResult(String actionName, String method) {
        this(null, actionName, method);
    }

    public ServletActionRedirectResult(String namespace, String actionName, String method) {
        super(null);
        this.namespace = namespace;
        this.actionName = actionName;
        this.method = method;
    }
    
    protected List<String> prohibitedResultParam = Arrays.asList(new String[] {
            DEFAULT_PARAM, "namespace", "method", "encode", "parse", "location",
            "prependServletContext" });

    /**
     * @see com.opensymphony.xwork2.Result#execute(com.opensymphony.xwork2.ActionInvocation)
     */
    public void execute(ActionInvocation invocation) throws Exception {
        actionName = conditionalParse(actionName, invocation);
        if (namespace == null) {
            namespace = invocation.getProxy().getNamespace();
        } else {
            namespace = conditionalParse(namespace, invocation);
        }
        if (method == null) {
            method = "";
        }
        else {
            method = conditionalParse(method, invocation);
        }

        String resultCode = invocation.getResultCode();
        if (resultCode != null) {
            ResultConfig resultConfig = invocation.getProxy().getConfig().getResults().get(
                    resultCode);
            Map resultConfigParams = resultConfig.getParams();
            for (Iterator i = resultConfigParams.entrySet().iterator(); i.hasNext(); ) {
                Map.Entry e = (Map.Entry) i.next();
                if (! prohibitedResultParam.contains(e.getKey())) {
                    requestParameters.put(e.getKey().toString(),
                            e.getValue() == null ? "":
                                conditionalParse(e.getValue().toString(), invocation));
                }
            }
        }

        StringBuffer tmpLocation = new StringBuffer(actionMapper.getUriFromActionMapping(new ActionMapping(actionName, namespace, method, null)));
        UrlHelper.buildParametersString(requestParameters, tmpLocation, "&");

        setLocation(tmpLocation.toString());

        super.execute(invocation);
    }

    /**
     * Sets the action name
     *
     * @param actionName The name
     */
    public void setActionName(String actionName) {
        this.actionName = actionName;
    }

    /**
     * Sets the namespace
     *
     * @param namespace The namespace
     */
    public void setNamespace(String namespace) {
        this.namespace = namespace;
    }

    /**
     * Sets the method
     *
     * @param method The method
     */
    public void setMethod(String method) {
        this.method = method;
    }

    /**
     * Adds a request parameter to be added to the redirect url
     *
     * @param key The parameter name
     * @param value The parameter value
     */
    public ServletActionRedirectResult addParameter(String key, Object value) {
        requestParameters.put(key, String.valueOf(value));
        return this;
    }

}