/*
    * This software was designed and created by Jason Carroll.
    * Copyright (c) 2002, 2003, 2004 Jason Carroll.
    * The author can be reached at jcarroll@cowsultants.com
    * ITracker website: http://www.cowsultants.com
    * ITracker forums: http://www.cowsultants.com/phpBB/index.php
    *
    * This program is free software; you can redistribute it and/or modify
    * it only under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program 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 General Public License for more details.
   */
  
  package org.itracker.services.util;
  
  import java.lang.reflect.Field;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  
  import org.apache.log4j.Logger;
  import org.apache.struts.action.ActionErrors;
  import org.apache.struts.action.ActionMessage;
  import org.apache.struts.action.ActionMessages;
  import org.apache.struts.validator.ValidatorForm;
  import org.itracker.core.resources.ITrackerResources;
  import org.itracker.model.NameValuePair;
  import org.itracker.model.ProjectScript;
  import org.itracker.services.exceptions.WorkflowException;
  
  import bsh.Interpreter;
  
  /**
   * Contains utilities used when displaying and processing workflow and field events
   */
  public class WorkflowUtilities  {
      
      /** Fires for each field when building the form.  Mainly used to build dynamic list options. */
      public static final int EVENT_FIELD_ONPOPULATE = 1;
      /** NOT CURRENTLY IMPLEMENTED.  Use the onPopulate event instead. In the future, this event may be implemented to allow for list sorting after list value population. */
      public static final int EVENT_FIELD_ONSORT = 2;
      /** Fires to set the current value of a form field.  This will overwrite any data in the form field pulled from the database. */
      public static final int EVENT_FIELD_ONSETDEFAULT = 3;
      /** Fires on validation of the form field. */
      public static final int EVENT_FIELD_ONVALIDATE = 4;
      /** Fires after validation, but before the data is committed to the database. */
      public static final int EVENT_FIELD_ONPRESUBMIT = 5;
      /** Fires after all data is submitted to the db for all fields. Performed right before the response is sent. */
      public static final int EVENT_FIELD_ONPOSTSUBMIT = 6;
      
      private static final Logger logger = Logger.getLogger(WorkflowUtilities.class);
      
      public WorkflowUtilities() {
      }
      
      /**
       * Returns a title of workflow event, according to selected locale.
       * @param value is an identifier of incoming event.
       * @param locale is a selected locale.
       * @return a name of event or something like "MISSING KEY: <resourceBundleKey>".
       */
      public static String getEventName(int value, Locale locale) {
          final String eventName = getEventName(Integer.toString(value), locale);
  //        assert null != eventName : "event name should never be null.";
          return eventName;
      }
      
      public static String getEventName(String value, Locale locale) {
          return ITrackerResources.getString(ITrackerResources.KEY_BASE_WORKFLOW_EVENT + value, locale);
      }
      
      /**
       * Returns an array of pairs (eventName, eventId), where eventName
       * is an event title, according to selected locale.
       * @param locale is a selected locale.
       * @return an array of pairs (eventName, eventId), which is never null.
       */
      public static NameValuePair[] getEvents(Locale locale) {
          NameValuePair[] eventNames = new NameValuePair[6];
          eventNames[0] = new NameValuePair(getEventName(EVENT_FIELD_ONPOPULATE, locale), Integer.toString(EVENT_FIELD_ONPOPULATE));
          eventNames[1] = new NameValuePair(getEventName(EVENT_FIELD_ONSORT, locale), Integer.toString(EVENT_FIELD_ONSORT));
          eventNames[2] = new NameValuePair(getEventName(EVENT_FIELD_ONSETDEFAULT, locale), Integer.toString(EVENT_FIELD_ONSETDEFAULT));
          eventNames[3] = new NameValuePair(getEventName(EVENT_FIELD_ONVALIDATE, locale), Integer.toString(EVENT_FIELD_ONVALIDATE));
          eventNames[4] = new NameValuePair(getEventName(EVENT_FIELD_ONPRESUBMIT, locale), Integer.toString(EVENT_FIELD_ONPRESUBMIT));
          eventNames[5] = new NameValuePair(getEventName(EVENT_FIELD_ONPOSTSUBMIT, locale), Integer.toString(EVENT_FIELD_ONPOSTSUBMIT));
          return eventNames;
      }
      
      /**
       * Select a list of NameValuePair objects from provided map object according
      * to fieldId selector. Typesafe version of #getListOptions(Map, Integer)
      * @param listOptions is a map, with stored NameValuePair objects lists
      * associated with specific integer id.
      * @param fieldId is a selector from map.
      * @return a list of objects, which may be empty, but never null.
      */
     public static List<NameValuePair> getListOptions(Map<Integer, List<NameValuePair>> listOptions, int fieldId) {
         return getListOptions(listOptions, Integer.valueOf(fieldId));
     }
     
     /**
      * Select a list of NameValuePair objects from provided map object according
      * to fieldId selector.
      * @param listOptions is a map, with stored NameValuePair objects lists
      * associated with specific integer id.
      * @param fieldId is a selector from map.
      * @return a list of objects, which may be empty, but never null.
      */
     @SuppressWarnings("unchecked")
     public static List<NameValuePair> getListOptions(Map listOptions, Integer fieldId) {
         List<NameValuePair> options = new ArrayList<NameValuePair>();
         
         if(listOptions != null && listOptions.size() != 0 && fieldId != null) {
             Object mapOptions = listOptions.get(fieldId);
             if(mapOptions != null) {
                 options = (List<NameValuePair>) mapOptions;
             }
         }
         
         return options;
     }
     
     /**
      * The most general way to run scripts. All matching of event and fields
      * are embedded within. As a result, currentValues parameter will
      * contain updated values and form will contain new default values
      * if appropriate.
      * @param projectScriptModels is a list of scripts.
      * @param event is an event type.
      * @param currentValues is a map of current values to fields.
      * @param currentErrors is a container for errors.
      * @param form contains default values of fields.
      * @throws org.itracker.services.exceptions.WorkflowException
      */
     public static void processFieldScripts(List<ProjectScript> projectScriptModels, int event, Map<Integer, List<NameValuePair>> currentValues, ActionMessages currentErrors, ValidatorForm form) throws WorkflowException {
         if(projectScriptModels == null || projectScriptModels.size() == 0) {
             return;
         }
         logger.debug("Processing " + projectScriptModels.size() + " field scripts for project " + projectScriptModels.get(0).getProject().getId());
         
         List<ProjectScript> scriptsToRun = new ArrayList<ProjectScript>();
         for(int i = 0; i < projectScriptModels.size(); i++) {
             if(projectScriptModels.get(i).getScript().getEvent() == event) {
                 int insertIndex = 0;
                 for(insertIndex = 0; insertIndex < scriptsToRun.size(); insertIndex++) {
                     if(projectScriptModels.get(i).getPriority() < ((ProjectScript) scriptsToRun.get(insertIndex)).getPriority()) {
                         break;
                     }
                 }
                 scriptsToRun.add(insertIndex,projectScriptModels.get(i));
             }
         }
         logger.debug(scriptsToRun.size() + " eligible scripts found for event " + event);
         
         if (currentValues == null) {
             currentValues = new HashMap<Integer, List<NameValuePair>>();
         }
         
         for (int i = 0; i < scriptsToRun.size(); i++) {
             ProjectScript currentScript = (ProjectScript) scriptsToRun.get(i);
             try {
                 logger.debug("Running script " + currentScript.getScript().getId() + " with priority " + currentScript.getPriority());
                 List<NameValuePair> currentValue = currentValues.get(currentScript.getFieldId());
                 
                 logger.debug("Before script current value for field " + IssueUtilities.getFieldName(currentScript.getFieldId()) + " (" + currentScript.getFieldId() + ") is " + (currentValue == null ? "NULL" : "'" + currentValue.toString() + "' (" + currentValue.getClass().getName() + "'"));
                 currentValue = processFieldScript(currentScript, event, currentScript.getFieldId(), currentValue, currentErrors, form);
                 logger.debug("After script current value for field " + IssueUtilities.getFieldName(currentScript.getFieldId()) + " (" + currentScript.getFieldId() + ") is " + (currentValue == null ? "NULL" : "'" + currentValue.toString() + "' (" + currentValue.getClass().getName() + "'"));
                 
                 currentValues.put(currentScript.getFieldId(), currentValue);
             } catch(WorkflowException we) {
                 logger.error("Error processing script " + currentScript.getScript().getId() + ": " + we.getMessage());
             }
         }
     }
     
     /**
      * Run appropriate script, selecting it from provided list by matching
      * event and field.
      * @param projectScripts is a list of provided scripts.
      * @param event is an event type.
      * @param fieldId is a field, associated with event.
      * @param currentValue is a set of current values.
      * @param currentErrors is a container for errors.
      * @param form is a form, holder of default values.
      * @return new set of values.
      * @throws org.itracker.services.exceptions.WorkflowException
      */
     public static List<NameValuePair> processFieldScripts(List<ProjectScript> projectScripts, int event, Integer fieldId, List<NameValuePair> currentValue, ActionErrors currentErrors, ValidatorForm form) throws WorkflowException {
         if(projectScripts == null || projectScripts.size() == 0 || fieldId == null) {
             return null;
         }
         logger.debug("Processing " + projectScripts.size() + " field scripts for project " + projectScripts.get(0).getProject().getId());
         
         List<ProjectScript> scriptsToRun = new LinkedList<ProjectScript>();
         for(int i = 0; i < projectScripts.size(); i++) {
             if(projectScripts.get(i).getScript().getEvent() == event && fieldId.equals(projectScripts.get(i).getFieldId())) {
                 int insertIndex = 0;
                 for(insertIndex = 0; insertIndex < scriptsToRun.size(); insertIndex++) {
                     if(projectScripts.get(i).getPriority() < ((ProjectScript) scriptsToRun.get(insertIndex)).getPriority()) {
                         break;
                     }
                 }
                 scriptsToRun.add(insertIndex,projectScripts.get(i));
             }
         }
         logger.debug(scriptsToRun.size() + " eligible scripts found for event " + event + " on field " + fieldId);
         
         for(int i = 0; i < scriptsToRun.size(); i++) {
             ProjectScript currentScript = (ProjectScript) scriptsToRun.get(i);
             try {
                 logger.debug("Running script " + currentScript.getScript().getId() + " with priority " + currentScript.getPriority());
                 currentValue = processFieldScript(currentScript, event, fieldId, currentValue, currentErrors, form);
             } catch(WorkflowException we) {
                 logger.error("Error processing script " + currentScript.getScript().getId() + ": " + we.getMessage());
             }
         }
         
         return currentValue;
     }
     
     /**
      * Run provided BEANSHELL script against form instance, taking into account
      * incoming event type, field raised an event and current values.
      * As a result, a set of new current values is returned and if
      * appropriate, default values are changed in form.
      * TODO: should issue, project, user, services be available too?
      * 
      * @param projectScript is a script to run.
      * @param event is an event type.
      * @param fieldId is a field id associated with event.
      * @param currentValues is a set of current values.
      * @param currentErrors is a container for occured errors.
      * @param form is a form instance, holding values.
      * @return new current values.
      * @throws org.itracker.services.exceptions.WorkflowException
      */
     public static List<NameValuePair> processFieldScript(ProjectScript projectScript, int event, Integer fieldId, List<NameValuePair> currentValues, ActionMessages currentErrors, ValidatorForm form) throws WorkflowException {
         if (projectScript == null) {
             throw new WorkflowException("ProjectScript was null.", WorkflowException.INVALID_ARGS);
         }
         if (currentErrors == null) {
             throw new WorkflowException("Errors was null.", WorkflowException.INVALID_ARGS);
         }
         
         try {
             Interpreter bshInterpreter = new Interpreter();
             bshInterpreter.set("event", event);
             bshInterpreter.set("fieldId", fieldId);
             // TODO: remove currentValue from bshInterpreter, it's a collection of current values.
             bshInterpreter.set("currentValue", currentValues);
             bshInterpreter.set("currentValues", currentValues);
             bshInterpreter.set("currentErrors", currentErrors);
             bshInterpreter.set("currentForm", form);
             bshInterpreter.eval(projectScript.getScript().getScript());
             // TODO: is this necessary? It should stay the same list-object..
 //            currentValues = (List<NameValuePair>)bshInterpreter.get("currentValue");
             if (logger.isDebugEnabled()) {
             	logger.debug("processFieldScript: Script returned current value of '" + currentValues + "' (" + (currentValues != null ? currentValues.getClass().getName() : "NULL") + ")");
             }
             if (event == EVENT_FIELD_ONSETDEFAULT && form != null && currentValues != null) {
             	if (logger.isDebugEnabled()) {
             		logger.debug("processFieldScript: Setting current form field value for field " + IssueUtilities.getFieldName(projectScript.getFieldId()) + " to '" + currentValues + "'");
             	}
                 setFormProperty(form, projectScript.getFieldId(), currentValues);
             }
         } catch(Exception e) {
             logger.error("processFieldScript: Error processing field script.", e);
             // TODO: error-handling..?
             currentErrors.add(ActionMessages.GLOBAL_MESSAGE, 
             		new ActionMessage("itracker.web.error.system.message", 
             				new Object[]{ITrackerResources.getString("itracker.web.attr.script"), // Script
             					e.getMessage()
             }));
         }
         if (logger.isDebugEnabled()) {
         	logger.debug("processFieldScript: returning " + currentValues + ", errors: " + currentErrors);
         }
         return currentValues;
     }
     
     @SuppressWarnings("unchecked")
     private static void setFormProperty(ValidatorForm form, Integer fieldId, Object currentValue) {
         String fieldName = IssueUtilities.getFieldName(fieldId);
         int fieldType = IssueUtilities.getFieldType(fieldId);
         if(fieldType == IssueUtilities.FIELD_TYPE_SINGLE) {
             try {
                 Field formField = form.getClass().getField( fieldName );
                 if ( formField != null ) {
                     formField.set( form , currentValue );
                 } else {
                     throw new IllegalArgumentException( "no field with name "
                             + fieldName + " found in form " + form );
                 }
             } catch ( NoSuchFieldException e ) {
                 e.printStackTrace();
             } catch ( IllegalAccessException e ) {
                 e.printStackTrace();
             }
         } else if(fieldType == IssueUtilities.FIELD_TYPE_INDEXED) {
             try {
                 Object indexedField = null;
                 Field formField = form.getClass().getField(fieldName);
                 indexedField = formField.get( form );
                 if ( indexedField instanceof List ) {
                     ((List)indexedField).set( 0 , currentValue );
                 } else if ( indexedField instanceof Collection ) {
                     ((Collection)indexedField).add( currentValue );
                 } else {
                     throw new IllegalArgumentException( "field with name "
                             + fieldName + " found in form " + form + " is of unknown type" );
                 }
             } catch ( NoSuchFieldException e ) {
                 e.printStackTrace();
             } catch ( IllegalAccessException e ) {
                 e.printStackTrace();
             }
         } else if(fieldType == IssueUtilities.FIELD_TYPE_MAP) {
             try {
                 Object indexedField = null;
                 Field formField = form.getClass().getField( fieldName );
                 indexedField = formField.get( form );
                 if ( indexedField instanceof Map ) {
                     ((Map)indexedField).put( fieldId.toString(), currentValue );
                 } else {
                     throw new IllegalArgumentException( "field with name "
                             + fieldName + " found in form " + form + " is of unknown type" );
                 }
             } catch ( NoSuchFieldException e ) {
                 e.printStackTrace();
             } catch ( IllegalAccessException e ) {
                 e.printStackTrace();
             }
         }
     }
     
 }