/*
    * 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.myfaces.tobago.component;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.myfaces.tobago.event.SortActionEvent;
  import org.apache.myfaces.tobago.internal.component.AbstractUICommand;
  import org.apache.myfaces.tobago.internal.component.AbstractUISheet;
  import org.apache.myfaces.tobago.model.SheetState;
  import org.apache.myfaces.tobago.util.BeanComparator;
  import org.apache.myfaces.tobago.util.ValueExpressionComparator;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.el.ValueExpression;
  import javax.faces.component.UIColumn;
  import javax.faces.component.UICommand;
  import javax.faces.component.UIComponent;
  import javax.faces.component.UIInput;
  import javax.faces.component.UIOutput;
  import javax.faces.component.UISelectBoolean;
  import javax.faces.component.UISelectMany;
  import javax.faces.component.UISelectOne;
  import javax.faces.context.FacesContext;
  import javax.faces.model.DataModel;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.List;
  
  public class Sorter {
  
    private static final Logger LOG = LoggerFactory.getLogger(Sorter.class);
  
    private Comparator comparator;
  
    public void perform(SortActionEvent sortEvent) {
      if (LOG.isDebugEnabled()) {
        LOG.debug("sorterId = {}", sortEvent.getComponent().getId());
      }
      UIColumn column = sortEvent.getColumn();
      AbstractUISheet data = (AbstractUISheet) sortEvent.getComponent();
  
      Object value = data.getValue();
      if (value instanceof DataModel) {
        value = ((DataModel) value).getWrappedData();
      }
      FacesContext facesContext = FacesContext.getCurrentInstance();
      SheetState sheetState = data.getSheetState(facesContext);
  
      Comparator actualComparator = null;
  
      if (value instanceof List || value instanceof Object[]) {
        String sortProperty;
  
        try {
          UIComponent child = getFirstSortableChild(column.getChildren());
          if (child != null) {
  
            String attributeName = child instanceof AbstractUICommand ? Attributes.LABEL : Attributes.VALUE;
            if (child.getValueExpression(attributeName) != null) {
              String var = data.getVar();
              if (var == null) {
                  LOG.error("No sorting performed. Property var of sheet is not set!");
                  unsetSortableAttribute(column);
                  return;
              }
              String expressionString = child.getValueExpression(attributeName).getExpressionString();
              if (isSimpleProperty(expressionString)) {
                if (expressionString.startsWith("#{")
                    && expressionString.endsWith("}")) {
                  expressionString =
                      expressionString.substring(2,
                          expressionString.length() - 1);
                }
                sortProperty = expressionString.substring(var.length() + 1);
  
                actualComparator = new BeanComparator(
                    sortProperty, comparator, !sheetState.isAscending());
  
                if (LOG.isDebugEnabled()) {
                 LOG.debug("Sort property is {}", sortProperty);
               }
             } else {
 
               boolean descending = !sheetState.isAscending();
               ValueExpression expression = child.getValueExpression("value");
               actualComparator = new ValueExpressionComparator(facesContext, var, expression, descending, comparator);
             }
           } else {
               LOG.error("No sorting performed. No Expression target found for sorting!");
               unsetSortableAttribute(column);
               return;
           }
         } else {
           LOG.error("No sorting performed. Value is not instanceof List or Object[]!");
           unsetSortableAttribute(column);
           return;
         }
       } catch (Exception e) {
         LOG.error("Error while extracting sortMethod :" + e.getMessage(), e);
         if (column != null) {
           unsetSortableAttribute(column);
         }
         return;
       }
 
       // TODO: locale / comparator parameter?
       // don't compare numbers with Collator.getInstance() comparator
 //        Comparator comparator = Collator.getInstance();
 //          comparator = new RowComparator(ascending, method);
 
       // memorize selected rows
       List<Object> selectedDataRows = null;
       if (sheetState.getSelectedRows().size() > 0) {
         selectedDataRows = new ArrayList<Object>(sheetState.getSelectedRows().size());
         Object dataRow;
         for (Integer index : sheetState.getSelectedRows()) {
           if (value instanceof List) {
             dataRow = ((List) value).get(index);
           } else {
             dataRow = ((Object[]) value)[index];
           }
           selectedDataRows.add(dataRow);
         }
       }
 
       // do sorting
       if (value instanceof List) {
         Collections.sort((List) value, actualComparator);
       } else { // value is instanceof Object[]
         Arrays.sort((Object[]) value, actualComparator);
       }
 
       // restore selected rows
       if (selectedDataRows != null) {
         sheetState.getSelectedRows().clear();
         for (Object dataRow : selectedDataRows) {
           int index = -1;
           if (value instanceof List) {
             for (int i = 0; i < ((List) value).size() && index < 0; i++) {
               if (dataRow == ((List) value).get(i)) {
                 index = i;
               }
             }
           } else {
             for (int i = 0; i < ((Object[]) value).length && index < 0; i++) {
               if (dataRow == ((Object[]) value)[i]) {
                 index = i;
               }
             }
           }
           if (index >= 0) {
             sheetState.getSelectedRows().add(index);
           }
         }
       }
 
     } else {  // DataModel?, ResultSet, Result or Object
       LOG.warn("Sorting not supported for type "
           + (value != null ? value.getClass().toString() : "null"));
     }
   }
 
   // XXX needs to be tested
   // XXX was based on ^#\{(\w+(\.\w)*)\}$ which is wrong, because there is a + missing after the last \w
   boolean isSimpleProperty(String expressionString) {
     if (expressionString.startsWith("#{") && expressionString.endsWith("}")) {
       String inner = expressionString.substring(2, expressionString.length() - 1);
       String[] parts = StringUtils.split(inner, ".");
       for (String part : parts) {
         if (!StringUtils.isAlpha(part)) {
           return false;
         }
       }
       return true;
     }
     return false;
   }
 
   private void unsetSortableAttribute(UIColumn uiColumn) {
     LOG.warn("removing attribute sortable from column " + uiColumn.getId());
     uiColumn.getAttributes().put(Attributes.SORTABLE, Boolean.FALSE);
   }
 
   private UIComponent getFirstSortableChild(List<UIComponent> children) {
     UIComponent result = null;
 
     for (UIComponent child : children) {
       result = child;
       if (child instanceof UISelectMany
           || child instanceof UISelectOne
           || child instanceof UISelectBoolean
           || (child instanceof AbstractUICommand && child.getChildren().isEmpty())
           || (child instanceof UIInput && RendererTypes.HIDDEN.equals(child.getRendererType()))) {
         continue;
         // look for a better component if any
       }
       if (child instanceof UIOutput) {
         break;
       }
       if (child instanceof UICommand
           || child instanceof javax.faces.component.UIPanel) {
         child = getFirstSortableChild(child.getChildren());
         if (child instanceof UIOutput) {
           break;
         }
       }
     }
     return result;
   }
 
   public Comparator getComparator() {
     return comparator;
   }
 
   public void setComparator(Comparator comparator) {
     this.comparator = comparator;
   }
 }