/*
    * 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.struts.apps.mailreader.actions;
  
  import org.apache.commons.beanutils.PropertyUtils;
  import org.apache.struts.action.ActionForm;
  import org.apache.struts.action.ActionForward;
  import org.apache.struts.action.ActionMapping;
  import org.apache.struts.apps.mailreader.Constants;
  import org.apache.struts.apps.mailreader.dao.Subscription;
  import org.apache.struts.apps.mailreader.dao.User;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpSession;
  import java.lang.reflect.InvocationTargetException;
  
  /**
   * <p>
   * Provide an Edit method for retrieving an existing subscription,
   * and a Save method for updating or inserting a subscription.
   * </p>
   */
  public final class SubscriptionAction extends BaseAction {
  
      // --- Public Constants --
  
      /**
       * <p>
       * Name of autoConnect field ["autoConnect"].
       * </p>
       */
      public final static String AUTO_CONNECT = "autoConnect";
  
      /**
       * <p>
       * Name of host field ["host"].
       * </p>
       */
      public final static String HOST = "host";
  
      /**
       * <p>
       * Name of type field ["type"].
       * </p>
       */
      public final static String TYPE = "type";
  
      // ---- Private Methods ----
  
      final String LOG_SUBSCRIPTION_POPULATE = "SubscriptionForm.populate";
  
      /**
       * <p>
       * Obtain subscription matching host for the given User,
       * or return null if not found.
       * </p>
       *
       * @param user Our User object
       * @param host The name of the mail server host
       * @return The matching Subscription or null
       */
      private Subscription doFindSubscription(User user, String host) {
  
          Subscription subscription;
  
          try {
              subscription = user.findSubscription(host);
          }
          catch (NullPointerException e) {
              subscription = null;
          }
  
          if ((subscription == null) && (log.isTraceEnabled())) {
              log.trace(
                      " No subscription for user "
                              + user.getUsername()
                              + " and host "
                              + host);
          }
  
          return subscription;
      }
  
     /**
      * <p>
      * Helper method to populate the Subscription object from the input form.
      * </p>
      *
      * @param subscription User object to populate
      * @param form         Form with incoming values
      * @throws ServletException On any error
      */
     private void doPopulate(Subscription subscription, ActionForm form)
             throws ServletException {
 
         if (log.isTraceEnabled()) {
             log.trace(Constants.LOG_POPULATE_SUBSCRIPTION + subscription);
         }
 
         try {
             PropertyUtils.copyProperties(subscription, form);
         } catch (InvocationTargetException e) {
             Throwable t = e.getTargetException();
             if (t == null) {
                 t = e;
             }
             log.error(LOG_SUBSCRIPTION_POPULATE, t);
             throw new ServletException(LOG_SUBSCRIPTION_POPULATE, t);
         } catch (Throwable t) {
             log.error(LOG_SUBSCRIPTION_POPULATE, t);
             throw new ServletException(LOG_SUBSCRIPTION_POPULATE, t);
         }
     }
 
     /**
      * <p>
      * Helper method to populate the input form from the Subscription object.
      * </p>
      *
      * @param subscription User object to populate
      * @param form         Form with incoming values
      * @throws ServletException On any error
      */
     private void doPopulate(ActionForm form, Subscription subscription)
             throws ServletException {
 
         final String title = Constants.EDIT;
 
         if (log.isTraceEnabled()) {
             log.trace(Constants.LOG_POPULATE_FORM + subscription.getHost());
         }
 
         try {
             PropertyUtils.copyProperties(form, subscription);
             doSet(form, TASK, title);
         } catch (InvocationTargetException e) {
             Throwable t = e.getTargetException();
             if (t == null) {
                 t = e;
             }
             log.error(LOG_SUBSCRIPTION_POPULATE, t);
             throw new ServletException(LOG_SUBSCRIPTION_POPULATE, t);
         } catch (Throwable t) {
             log.error(LOG_SUBSCRIPTION_POPULATE, t);
             throw new ServletException(LOG_SUBSCRIPTION_POPULATE, t);
         }
     }
 
     /**
      * <p>
      * Remove the given subscription for this user.
      * </p>
      *
      * @param mapping      Our ActionMapping
      * @param session      Our HttpSession
      * @param user         Our User
      * @param subscription Subscription to delete
      * @return "Success" if delete is nominal, "Logon" if attributes are
      *         missing
      * @throws ServletException if updates fails
      */
     private ActionForward doRemoveSubscription(
             ActionMapping mapping,
             HttpSession session,
             User user,
             Subscription subscription)
             throws ServletException {
 
         final String method = Constants.DELETE;
         doLogProcess(mapping, method);
 
         if (log.isTraceEnabled()) {
             log.trace(
                     " Deleting subscription to mail server '"
                             + subscription.getHost()
                             + "' for user '"
                             + user.getUsername()
                             + "'");
         }
 
         boolean missingAttributes = ((user == null) || (subscription == null));
         if (missingAttributes) {
             return doFindLogon(mapping);
         }
 
         user.removeSubscription(subscription);
         session.removeAttribute(Constants.SUBSCRIPTION_KEY);
         doSaveUser(user);
 
         return doFindSuccess(mapping);
     }
 
     // ----- Public Methods ----
 
     /**
      * <p>
      * Prepare for a Delete operation by populating the form
      * and seting the action to Delete.
      * </p>
      *
      * @param mapping  Our ActionMapping
      * @param form     Our ActionForm
      * @param request  Our HttpServletRequest
      * @param response Our HttpServletResponse
      * @return The "Success" result for this mapping
      * @throws Exception on any error
      */
     public ActionForward Delete(
             ActionMapping mapping,
             ActionForm form,
             HttpServletRequest request,
             HttpServletResponse response)
             throws Exception {
 
         final String method = Constants.DELETE;
         doLogProcess(mapping, method);
 
         ActionForward result = Edit(mapping, form, request, response);
 
         doSet(form, TASK, method);
         return result;
     }
 
     /**
      * <p>
      * Retrieve the Subscription object to edit
      * or null if the Subscription does not exist.
      * </p><p>
      * The Subscription object is bound to the User,
      * and so if the User is not logged in,
      * control is forwarded to the Logon result.
      * </p>
      *
      * @param mapping  Our ActionMapping
      * @param form     Our ActionForm
      * @param request  Our HttpServletRequest
      * @param response Our HttpServletResponse
      * @return The "Success" result for this mapping
      * @throws Exception on any error
      */
     public ActionForward Edit(
             ActionMapping mapping,
             ActionForm form,
             HttpServletRequest request,
             HttpServletResponse response)
             throws Exception {
 
         final String method = Constants.EDIT;
         doLogProcess(mapping, method);
 
         HttpSession session = request.getSession();
         User user = doGetUser(session);
         if (user == null) {
             return doFindLogon(mapping);
         }
 
         // Retrieve the subscription, if there is one
         Subscription subscription;
         String host = doGet(form, HOST);
         boolean updating = (host != null);
         if (updating) {
             subscription = doFindSubscription(user, host);
             if (subscription == null) {
                 return doFindFailure(mapping);
             }
             session.setAttribute(Constants.SUBSCRIPTION_KEY, subscription);
             doPopulate(form, subscription);
             doSet(form, TASK, method);
         }
 
         return doFindSuccess(mapping);
     }
 
     /**
      * <p>
      * Insert or update a Subscription object to the persistent store.
      * </p>
      *
      * @param mapping  Our ActionMapping
      * @param form     Our ActionForm
      * @param request  Our HttpServletRequest
      * @param response Our HttpServletResponse
      * @return The "Success" result for this mapping
      * @throws Exception on any error
      */
     public ActionForward Save(
             ActionMapping mapping,
             ActionForm form,
             HttpServletRequest request,
             HttpServletResponse response)
             throws Exception {
 
         final String method = Constants.SAVE;
         doLogProcess(mapping, method);
 
         User user = doGetUser(request);
         if (user == null) {
             return doFindLogon(mapping);
         }
 
         HttpSession session = request.getSession();
         if (isCancelled(request)) {
             doCancel(session, method, Constants.SUBSCRIPTION_KEY);
             return doFindSuccess(mapping);
         }
 
         String action = doGet(form, TASK);
         Subscription subscription = doGetSubscription(request);
         boolean isDelete = action.equals(Constants.DELETE);
         if (isDelete) {
             return doRemoveSubscription(mapping, session, user, subscription);
         }
 
         if (subscription == null) {
             subscription = user.createSubscription(doGet(form, HOST));
             session.setAttribute(Constants.SUBSCRIPTION_KEY, subscription);
         }
 
         doPopulate(subscription, form);
         doSaveUser(user);
         session.removeAttribute(Constants.SUBSCRIPTION_KEY);
 
         return doFindSuccess(mapping);
     }
 
 }