/**
    * Copyright 2005-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.rice.krad.uif.modifier;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.log4j.Logger;
  import org.kuali.rice.krad.service.KRADServiceLocatorWeb;
  import org.kuali.rice.krad.uif.UifConstants;
  import org.kuali.rice.krad.uif.UifPropertyPaths;
  import org.kuali.rice.krad.uif.container.Group;
  import org.kuali.rice.krad.uif.field.DataField;
  import org.kuali.rice.krad.uif.view.View;
  import org.kuali.rice.krad.uif.component.Component;
  import org.kuali.rice.krad.uif.field.HeaderField;
  import org.kuali.rice.krad.uif.util.ComponentUtils;
  import org.kuali.rice.krad.uif.util.ObjectPropertyUtils;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * Generates <code>Field</code> instances to produce a comparison view among
   * objects of the same type
   *
   * <p>
   * Modifier is initialized with a List of <code>ComparableInfo</code> instances.
   * For each comparable info, a copy of the configured group field is made and
   * adjusted to the binding object path for the comparable. The comparison fields
   * are ordered based on the configured order property of the comparable. In
   * addition, a <code>HeaderField<code> can be generated to label each group
   * of comparison fields.
   * </p>
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class CompareFieldCreateModifier extends ComponentModifierBase {
      private static final Logger LOG = Logger.getLogger(CompareFieldCreateModifier.class);
  
      private static final long serialVersionUID = -6285531580512330188L;
  
      private int defaultOrderSequence;
      private boolean generateCompareHeaders;
  
      private HeaderField headerFieldPrototype;
      private List<ComparableInfo> comparables;
  
      public CompareFieldCreateModifier() {
          defaultOrderSequence = 1;
          generateCompareHeaders = true;
  
          comparables = new ArrayList<ComparableInfo>();
      }
  
      /**
       * Calls <code>ViewHelperService</code> to initialize the header field prototype
       *
       * @see org.kuali.rice.krad.uif.modifier.ComponentModifier#performInitialization(org.kuali.rice.krad.uif.view.View,
       *      java.lang.Object, org.kuali.rice.krad.uif.component.Component)
       */
      @Override
      public void performInitialization(View view, Object model, Component component) {
          super.performInitialization(view, model, component);
  
          if (headerFieldPrototype != null) {
              view.getViewHelperService().performComponentInitialization(view, model, headerFieldPrototype);
          }
      }
  
      /**
       * Generates the comparison fields
       *
       * <p>
       * First the configured List of <code>ComparableInfo</code> instances are
       * sorted based on their order property. Then if generateCompareHeaders is
       * set to true, a <code>HeaderField</code> is created for each comparable
       * using the headerFieldPrototype and the headerText given by the
       * comparable. Finally for each field configured on the <code>Group</code>,
       * a corresponding comparison field is generated for each comparable and
       * adjusted to the binding object path given by the comparable in addition
       * to suffixing the id and setting the readOnly property
       * </p>
       *
      * @see org.kuali.rice.krad.uif.modifier.ComponentModifier#performModification(org.kuali.rice.krad.uif.view.View,
      *      java.lang.Object, org.kuali.rice.krad.uif.component.Component)
      */
     @SuppressWarnings("unchecked")
     @Override
     public void performModification(View view, Object model, Component component) {
         if ((component != null) && !(component instanceof Group)) {
             throw new IllegalArgumentException(
                     "Compare field initializer only support Group components, found type: " + component.getClass());
         }
 
         if (component == null) {
             return;
         }
 
         // list to hold the generated compare items
         List<Component> comparisonItems = new ArrayList<Component>();
 
         // sort comparables by their order property
         List<ComparableInfo> groupComparables = (List<ComparableInfo>) ComponentUtils.sort(comparables,
                 defaultOrderSequence);
 
         // evaluate expressions on comparables
         Map<String, Object> context = new HashMap<String, Object>();
         context.putAll(view.getContext());
         context.put(UifConstants.ContextVariableNames.COMPONENT, component);
 
         for (ComparableInfo comparable : groupComparables) {
             KRADServiceLocatorWeb.getExpressionEvaluatorService().evaluateObjectExpressions(comparable, model,
                     context);
         }
 
         // generate compare header
         if (isGenerateCompareHeaders()) {
             for (ComparableInfo comparable : groupComparables) {
                 HeaderField compareHeaderField = ComponentUtils.copy(headerFieldPrototype, comparable.getIdSuffix());
                 compareHeaderField.setHeaderText(comparable.getHeaderText());
 
                 comparisonItems.add(compareHeaderField);
             }
         }
 
         // find the comparable to use for comparing value changes (if
         // configured)
         boolean performValueChangeComparison = false;
         String compareValueObjectBindingPath = null;
         for (ComparableInfo comparable : groupComparables) {
             if (comparable.isCompareToForValueChange()) {
                 performValueChangeComparison = true;
                 compareValueObjectBindingPath = comparable.getBindingObjectPath();
             }
         }
 
         // generate the compare items from the configured group
         Group group = (Group) component;
         for (Component item : group.getItems()) {
             int defaultSuffix = 0;
             for (ComparableInfo comparable : groupComparables) {
                 String idSuffix = comparable.getIdSuffix();
                 if (StringUtils.isBlank(idSuffix)) {
                     idSuffix = UifConstants.IdSuffixes.COMPARE + defaultSuffix;
                 }
 
                 Component compareItem = ComponentUtils.copy(item, idSuffix);
 
                 ComponentUtils.setComponentPropertyDeep(compareItem, UifPropertyPaths.BIND_OBJECT_PATH,
                         comparable.getBindingObjectPath());
                 if (comparable.isReadOnly()) {
                     compareItem.setReadOnly(true);
                     if (compareItem.getPropertyExpressions().containsKey("readOnly")) {
                         compareItem.getPropertyExpressions().remove("readOnly");
                     }
                 }
 
                 // do value comparison
                 if (performValueChangeComparison && comparable.isHighlightValueChange() && !comparable
                         .isCompareToForValueChange()) {
                     performValueComparison(group, compareItem, model, compareValueObjectBindingPath);
                 }
 
                 comparisonItems.add(compareItem);
                 defaultSuffix++;
             }
         }
 
         // update the group's list of components
         group.setItems(comparisonItems);
     }
 
     /**
      * For each attribute field in the compare item, retrieves the field value and compares against the value for the
      * main comparable. If the value is different, adds script to the field on ready event to add the change icon to
      * the field and the containing group header
      *
      * @param group - group that contains the item and whose header will be highlighted for changes
      * @param compareItem - the compare item being generated and to pull attribute fields from
      * @param model - object containing the data
      * @param compareValueObjectBindingPath - object path for the comparison item
      */
     protected void performValueComparison(Group group, Component compareItem, Object model,
             String compareValueObjectBindingPath) {
         // get any attribute fields for the item so we can compare the values
         List<DataField> itemFields = ComponentUtils.getComponentsOfTypeDeep(compareItem, DataField.class);
         for (DataField field : itemFields) {
             String fieldBindingPath = field.getBindingInfo().getBindingPath();
             Object fieldValue = ObjectPropertyUtils.getPropertyValue(model, fieldBindingPath);
 
             String compareBindingPath = StringUtils.replaceOnce(fieldBindingPath,
                     field.getBindingInfo().getBindingObjectPath(), compareValueObjectBindingPath);
             Object compareValue = ObjectPropertyUtils.getPropertyValue(model, compareBindingPath);
 
             boolean valueChanged = false;
             if (!((fieldValue == null) && (compareValue == null))) {
                 // if one is null then value changed
                 if ((fieldValue == null) || (compareValue == null)) {
                     valueChanged = true;
                 } else {
                     // both not null, compare values
                     valueChanged = !fieldValue.equals(compareValue);
                 }
             }
 
             // add script to show change icon
             if (valueChanged) {
                 String onReadyScript = "showChangeIcon('" + field.getId() + "');";
 
                 // add icon to group header
                 Component headerField = group.getHeader();
                 onReadyScript += "showChangeIconOnHeader('" + headerField.getId() + "');";
 
                 field.setOnDocumentReadyScript(onReadyScript);
             }
 
             // TODO: add script for value changed?
         }
     }
 
     /**
      * Generates an id suffix for the comparable item
      *
      * <p>
      * If the idSuffix to use if configured on the <code>ComparableInfo</code>
      * it will be used, else the given integer index will be used with an
      * underscore
      * </p>
      *
      * @param comparable - comparable info to check for id suffix
      * @param index - sequence integer
      * @return String id suffix
      * @see org.kuali.rice.krad.uif.modifier.ComparableInfo.getIdSuffix()
      */
     protected String getIdSuffix(ComparableInfo comparable, int index) {
         String idSuffix = comparable.getIdSuffix();
         if (StringUtils.isBlank(idSuffix)) {
             idSuffix = "_" + index;
         }
 
         return idSuffix;
     }
 
     /**
      * @see org.kuali.rice.krad.uif.modifier.ComponentModifier#getSupportedComponents()
      */
     @Override
     public Set<Class<? extends Component>> getSupportedComponents() {
         Set<Class<? extends Component>> components = new HashSet<Class<? extends Component>>();
         components.add(Group.class);
 
         return components;
     }
 
     /**
      * @see org.kuali.rice.krad.uif.modifier.ComponentModifierBase#getComponentPrototypes()
      */
     public List<Component> getComponentPrototypes() {
         List<Component> components = new ArrayList<Component>();
 
         components.add(headerFieldPrototype);
 
         return components;
     }
 
     /**
      * Indicates the starting integer sequence value to use for
      * <code>ComparableInfo</code> instances that do not have the order property
      * set
      *
      * @return int default sequence starting value
      */
     public int getDefaultOrderSequence() {
         return this.defaultOrderSequence;
     }
 
     /**
      * Setter for the default sequence starting value
      *
      * @param defaultOrderSequence
      */
     public void setDefaultOrderSequence(int defaultOrderSequence) {
         this.defaultOrderSequence = defaultOrderSequence;
     }
 
     /**
      * Indicates whether a <code>HeaderField</code> should be created for each
      * group of comparison fields
      *
      * <p>
      * If set to true, for each group of comparison fields a header field will
      * be created using the headerFieldPrototype configured on the modifier with
      * the headerText property of the comparable
      * </p>
      *
      * @return boolean true if the headers should be created, false if no
      *         headers should be created
      */
     public boolean isGenerateCompareHeaders() {
         return this.generateCompareHeaders;
     }
 
     /**
      * Setter for the generate comparison headers indicator
      *
      * @param generateCompareHeaders
      */
     public void setGenerateCompareHeaders(boolean generateCompareHeaders) {
         this.generateCompareHeaders = generateCompareHeaders;
     }
 
     /**
      * Prototype instance to use for creating the <code>HeaderField</code> for
      * each group of comparison fields (if generateCompareHeaders is true)
      *
      * @return HeaderField header field prototype
      */
     public HeaderField getHeaderFieldPrototype() {
         return this.headerFieldPrototype;
     }
 
     /**
      * Setter for the header field prototype
      *
      * @param headerFieldPrototype
      */
     public void setHeaderFieldPrototype(HeaderField headerFieldPrototype) {
         this.headerFieldPrototype = headerFieldPrototype;
     }
 
     /**
      * List of <code>ComparableInfo</code> instances the compare fields should
      * be generated for
      *
      * <p>
      * For each comparable, a copy of the fields configured for the
      * <code>Group</code> will be created for the comparison view
      * </p>
      *
      * @return List<ComparableInfo> comparables to generate fields for
      */
     public List<ComparableInfo> getComparables() {
         return this.comparables;
     }
 
     /**
      * Setter for the list of comparable info instances
      *
      * @param comparables
      */
     public void setComparables(List<ComparableInfo> comparables) {
         this.comparables = comparables;
     }
 
 }