/*
    * Copyright 2008 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.ole.sys.document.service.impl;
  
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import org.kuali.ole.sys.document.service.AccountingLineTableTransformation;
  import org.kuali.ole.sys.document.web.AccountingLineTableCell;
  import org.kuali.ole.sys.document.web.AccountingLineTableRow;
  import org.kuali.ole.sys.document.web.RenderableElement;
  
  /**
   * A transformation which takes all of the non-visible hidden fields of the accounting line and moves them
   * to the first possible position
   */
  public class HiddenFieldRearrangementAccountingLineRenderingTransformationImpl implements AccountingLineTableTransformation {
  
      public void transformRows(List<AccountingLineTableRow> rows) {
          // 1. find the first top-level container element with non-hidden variables
          AccountingLineTableCell cell = findFirstNonHiddenCell(rows);
          // 2. move all the hidden fields
          for (AccountingLineTableRow row : rows) {
              moveHiddenFields(row, cell);
          }
      }
      
      /**
       * Finds the first top-level non-hidden container from the given list of elements
       * @param elements the elements to find the first non-hidden container from
       * @return the first top-level non-hidden container
       */
      protected AccountingLineTableCell findFirstNonHiddenCell(List<AccountingLineTableRow> rows) {
          for (AccountingLineTableRow row : rows) {
              for (AccountingLineTableCell cell : row.getCells()) {
                  if (!cell.isHidden()) {
                      return cell;
                  }
              }
          }
          throw new IllegalArgumentException("The renderable element tree specified does not seem to have any elements that will display as non-hidden specified");
      }
      
      /**
       * Moves any hidden fields in the source container to the target container 
       * @param sourceContainer the container which may have hidden fields
       * @param targetContainer the container which should be carrying all hidden fields
       */
      protected void moveHiddenFields(AccountingLineTableRow sourceRow, AccountingLineTableCell targetCell) {
          for (AccountingLineTableCell cell : sourceRow.getCells()) {
              moveHiddenFields(cell, targetCell);
          }
      }
      
      /**
       * Moves any hidden renderable fields in the source cell to the target cell
       * @param sourceCell the source cell to move hidden elements from
       * @param targetCell the target cell to move hidden elements to
       */
      protected void moveHiddenFields(AccountingLineTableCell sourceCell, AccountingLineTableCell targetCell) {
          Set<RenderableElement> renderableElementsToRemove = new HashSet<RenderableElement>();
          for (RenderableElement element : sourceCell.getRenderableElement()) {
              if (element.isHidden()) {
                  renderableElementsToRemove.add(element);
              }
          }
          sourceCell.getRenderableElement().removeAll(renderableElementsToRemove);
          targetCell.getRenderableElement().addAll(renderableElementsToRemove);
      }
  }