/*
    * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/event/EventEngine.java,v 1.40 2006/02/17 11:37:32 hkollmann Exp $
    * $Revision: 1.40 $
    * $Date: 2006/02/17 11:37:32 $
    *
    * DbForms - a Rapid Application Development Framework
    * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
    *
    * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */
  
  package org.dbforms.event;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.dbforms.config.Constants;
  import org.dbforms.config.DbFormsConfig;
  import org.dbforms.config.Table;
  
  import org.dbforms.event.eventtype.EventType;
  import org.dbforms.event.eventtype.EventTypeUtil;
  
  import org.dbforms.util.ParseUtil;
  import org.dbforms.util.StringUtil;
  import org.dbforms.util.Util;
  
  import java.util.Enumeration;
  import java.util.Vector;
  
  import javax.servlet.http.HttpServletRequest;
  
  
  
  /***
   * This class is invoked by the Controller-Servlet. It parses a request to find
   * out which Event(s) need to be instanciated. The fine-grained parsing
   * (parsing of additional data, etc) is done by the WebEvent-Object itself (in
   * order to hide complexity from this class and to keep the framework open for
   * implementations of new Event-classes)
   *
   * @author Joe Peer
   *
   */
  public class EventEngine {
     /*** logging category for this class */
     private static Log logCat = LogFactory.getLog(EventEngine.class.getName());
  
     /*** instance of DatabaseEventFactory */
     private AbstractDatabaseEventFactory dbEventFactory = DatabaseEventFactoryImpl
                                                   .instance();
     private DbFormsConfig        config;
     private HttpServletRequest   request;
  
     /*** instance of NavigationEventFactory */
     private AbstractNavEventFactory navEventFactory = NavEventFactoryImpl.instance();
  
     /***
      * this vector will contain which tables where on the jsp page: one jsp file
      * may contain multiple dbforms, and each forms could contain many subforms
      * nested inside
      */
     private Vector involvedTables;
  
     /***
      * Constructor.
      *
      * @param request the request object
      * @param config the configuration object
      */
     public EventEngine(HttpServletRequest request,
                        DbFormsConfig      config) {
        this.request = request;
        this.config  = config;
  
        // find out which tables where on the jsp
        involvedTables = parseInvolvedTables();
     }
  
     /***
      * Get the involvedTables attribute of the EventEngine class.
      *
      * @return the involvedTables attribute of the EventEngine class
      */
     public Vector getInvolvedTables() {
        return involvedTables;
     }
 
 
    /***
     * Generate the primary event object, depending on the data contained into
     * the incoming http request object.
     *
     * @return a new WebEvent object
     */
    public AbstractWebEvent generatePrimaryEvent() {
       AbstractWebEvent e      = null;
       String   action = ParseUtil.getFirstParameterStartingWith(request, "ac_");
       String   customEvent = ParseUtil.getParameter(request, "customEvent");
 
       if (Util.isNull(action) && !Util.isNull(customEvent)) {
          // 2003-07-21-HKK: fixing NS 4.79 bug! (From bug list)
          action = customEvent.trim();
       }
 
       // NOOP EVENT
       //
       // family: web event
       if (Util.isNull(action)) {
          logCat.info("##### N O O P   ELEMENT ######");
          e = new NoopEvent(-1, request, config);
          initializeWebEvent(e);
 
          return e;
       }
 
       // RELOAD EVENT
       //
       // family: web event
       //
       // ReloadEvent use to refresh field values from request object
       // and to allow server side manipulation for these fields
       //
       // This event is created if customEvent is set to re_x_x!!
       //
       if (action.startsWith("re_")) {
          logCat.info("##### RELOAD  EVENT ######");
          e = new PageReloadEvent(StringUtil.getEmbeddedStringAsInteger(action,
                                                                       2, '_'),
                                  request, config);
          e.setType(EventType.EVENT_NAVIGATION_RELOAD);
          initializeWebEvent(e);
 
          return e;
       }
 
       // make the image button data (if any) look like a submit button;
       action = getImageButtonAction(action);
 
       // get the EventType class and identify the event type
       // and use the related factory class to create the event;
       EventType eventType = EventTypeUtil.getEventType(action);
 
       switch (eventType.getEventGroup()) {
          case EventType.EVENT_GROUP_DATABASE: {
             logCat.info("::generatePrimaryEvent - generating a database event");
             e = dbEventFactory.createEvent(action, request, config);
 
             break;
          }
 
          case EventType.EVENT_GROUP_NAVIGATION: {
             logCat.info("::generatePrimaryEvent - generating a navigation event");
             e = navEventFactory.createEvent(action, request, config);
 
             break;
          }
 
          default: {
             logCat.error("::generatePrimaryEvent - WARNING: generating NO event. Why ?");
 
             break;
          }
       }
 
       // setting the followUp attributes for the generated event
       setEventFollowUp(e, action);
 
       return e;
    }
 
 
    /***
     * Generate secundary events (update events)
     *
     * @param actTable DOCUMENT ME!
     * @param exclude the parent web event (related to the main form)
     *
     * @return DOCUMENT ME!
     */
    public Enumeration generateSecundaryEvents(Table    actTable,
                                               AbstractWebEvent exclude) {
       Vector  result           = new Vector();
       int     excludeTableId   = -1;
       String  excludeKeyId     = null;
       boolean collissionDanger = false;
 
       // first of all, we check if there is some real potential for collisions
       // in the "to exclude"-event
       if (exclude instanceof AbstractDatabaseEvent) {
          collissionDanger = true;
          excludeTableId   = exclude.getTable().getId();
          excludeKeyId     = ((AbstractDatabaseEvent) exclude).getKeyId();
       }
 
       String param = "autoupdate_" + String.valueOf(actTable.getId());
       String res = ParseUtil.getParameter(request, param);
 
       // auto-updating may be disabled, so we have to check:
       if (res.equalsIgnoreCase("true") || (res.equalsIgnoreCase("OnUpdateOnly") && exclude.getType().equals("update"))) {
          // we can only update existing rowsets. so we just look for
          // key-values
          String      paramStub          = "k_" + actTable.getId() + "_";
          Enumeration keysOfCurrentTable = ParseUtil.getParametersStartingWith(request,
                                                                               paramStub)
                                                    .elements();
 
          while (keysOfCurrentTable.hasMoreElements()) {
             String aKeyParam = (String) keysOfCurrentTable.nextElement();
             String keyId = aKeyParam.substring(paramStub.length());
 
             logCat.info("autoaupdate debug info: keyId=" + keyId
                         + " excludeKeyId=" + excludeKeyId);
 
             if ( !collissionDanger || (excludeTableId != actTable.getId()) || !keyId.equals(excludeKeyId) ) {
                AbstractDatabaseEvent e = dbEventFactory.createUpdateEvent(actTable.getId(),
                                                                   keyId,
                                                                   request,
                                                                   config);
                result.addElement(e);
             }
          }
 
          // now try the same with insert records
          if ( !collissionDanger || (excludeTableId != actTable.getId()) ) {
             paramStub = "f_" + actTable.getId() + "_"
                         + Constants.FIELDNAME_INSERTPREFIX;
             Vector v = ParseUtil.getParametersStartingWith(request, paramStub);
             if (v.size() > 0) {
                String aKeyParam = (String) v.firstElement();
                String keyId = aKeyParam.substring(paramStub.length());
                keyId = StringUtil.getEmbeddedString(keyId, 0, '_');
                AbstractDatabaseEvent e = dbEventFactory.createInsertEvent(actTable
                                                                   .getId(),
                                                                   keyId,
                                                                   request,
                                                                   config);
                result.addElement(e);
             }
          }
       }
 
       return result.elements();
    }
 
 
    /***
     * Sets the eventFollowUp and followUpOnError attributes of the input Event
     * object
     *
     * @param e the event object
     * @param action the action string
     */
    private void setEventFollowUp(AbstractWebEvent e,
                                  String   action) {
       // now we have to find the followup-site the app-developer wants us to
       // display.
       String followUp = ParseUtil.getParameter(request, "data" + action + "_fu");
 
       // if not...
       // ...then check if §2-followup exists (should always exist!)
       if (followUp == null) {
          followUp = ParseUtil.getParameter(request,
                                            "fu_"
                                            + (((e == null)
                                               || (e.getTable() == null)) ? (-1)
                                                                          : e.getTable().getId()));
       }
 
       logCat.info("setting follow up to:" + followUp);
 
       if (e != null) {
          e.setFollowUp(followUp);
       }
 
       String followUpOnError = ParseUtil.getParameter(request,
                                                       "data" + action + "_fue");
 
       // if not...
       // ...then check if §2-followup exists
       if (followUpOnError == null) {
          followUpOnError = ParseUtil.getParameter(request,
                                                   "fue_"
                                                   + (((e == null)
                                                      || (e.getTable() == null))
                                                      ? (-1)
                                                      : e.getTable().getId()));
       }
 
       // Still no followup on error - use general followup
       if (followUpOnError == null) {
          followUpOnError = followUp;
       }
 
       logCat.info("setting follow up on Error to:" + followUpOnError);
 
       if (e != null) {
          e.setFollowUpOnError(followUpOnError);
       }
    }
 
 
    /***
     * Make the image button data look like a submit button. <br>
     * Image buttons submit different parameters than submit buttons for submit
     * the browser sends one value parameter:ac_insert_0_root=Submit this bug!
     * for image buttons, the browser returns two values, showing the x and y
     * position of the mouse parameter ac_insert_0_root.y=24 parameter
     * ac_insert_0_root.x=34
     *
     * @param action Description of the Parameter
     *
     * @return The imageButtonAction value
     */
    private String getImageButtonAction(String action) {
       if (action.endsWith(".y") || action.endsWith(".x")) {
          action = action.substring(0, action.length() - 2);
       }
 
       logCat.info("::getImageButtonAction - action = [" + action + "]");
 
       return action;
    }
 
 
    /***
     * PRIVATE METHODS here
     *
     * @param contextPath DOCUMENT ME!
     * @param sourcePath DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    /***
     * Sets the sourcePath attribute of the EventEngine object
     *
     * @param contextPath The new sourcePath value
     * @param sourcePath The new sourcePath value
     *
     * @return Description of the Return Value
     */
    private String setSourcePath(String contextPath,
                                 String sourcePath) {
       if (!Util.isNull(contextPath)
                 && !Util.isNull(sourcePath)
                 && sourcePath.startsWith(contextPath)) {
          // shouldn't! just make sure!
          if (contextPath.endsWith("/")) {
             sourcePath = sourcePath.substring(contextPath.length() - 1);
          } else {
             sourcePath = sourcePath.substring(contextPath.length());
          }
       }
 
       return sourcePath;
    }
 
 
    /***
     * Initialize the input web event.
     *
     * @param e the web event to initialize
     */
    private void initializeWebEvent(AbstractWebEvent e) {
       String contextPath = request.getContextPath();
       String sourcePath = ParseUtil.getParameter(request, "source");
 
       logCat.info("sourcePath = " + sourcePath);
       sourcePath = setSourcePath(contextPath, sourcePath);
 
       e.setFollowUp(sourcePath);
       logCat.info("followup=" + e.getFollowUp());
    }
 
 
    /***
     * Find out which tables where on the jsp (one jsp file may contain multiple
     * dbforms, and each forms could contain many subforms nested inside!)
     *
     * @return the vector object containing the Table objects involved with the
     *         main table
     */
    private Vector parseInvolvedTables() {
       String[] invTables = ParseUtil.getParameterValues(request, "invtable");
 
       // in empty forms, for example, we don't have any involved tables..!
       if (invTables == null) {
          return null;
       }
 
       Vector result = new Vector();
 
       for (int i = 0; i < invTables.length; i++) {
          int   tableIndex = Integer.parseInt(invTables[i]);
          Table t = config.getTable(tableIndex);
 
          result.addElement(t);
       }
 
       return result;
    }
 }