/**
    * Copyright 2005-2014 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.layout.collections;
  
  import java.io.StringReader;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import javax.json.Json;
  import javax.json.JsonArray;
  import javax.json.JsonObject;
  import javax.json.JsonReader;
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.commons.collections.CollectionUtils;
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.krad.uif.UifConstants;
  import org.kuali.rice.krad.uif.container.CollectionGroup;
  import org.kuali.rice.krad.uif.lifecycle.ViewLifecycle;
  import org.kuali.rice.krad.uif.util.ColumnSort;
  import org.kuali.rice.krad.uif.util.MultiColumnComparator;
  import org.kuali.rice.krad.uif.util.ObjectPropertyUtils;
  import org.kuali.rice.krad.uif.view.View;
  import org.kuali.rice.krad.uif.view.ViewModel;
  
  /**
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class DataTablesPagingHelper {
  
      public static void processPagingRequest(View view, ViewModel form, CollectionGroup collectionGroup,
              DataTablesInputs dataTablesInputs) {
          if (view == null) {
              return;
          }
  
          String collectionGroupId = collectionGroup.getId();
  
          List<ColumnSort> newColumnSorts;
          synchronized (view) {
              // get the collection for this group from the model
              List<Object> modelCollection = ObjectPropertyUtils.getPropertyValue(form,
                      collectionGroup.getBindingInfo().getBindingPath());
  
              List<ColumnSort> oldColumnSorts =
                      (List<ColumnSort>) ViewLifecycle.getViewPostMetadata().getComponentPostData(collectionGroupId,
                              UifConstants.IdSuffixes.COLUMN_SORTS);
  
              newColumnSorts = buildColumnSorts(view, form, dataTablesInputs, collectionGroup);
  
              applyTableJsonSort(modelCollection, oldColumnSorts, newColumnSorts, collectionGroup, form, view);
  
              // set up the collection group properties related to paging in the collection group to set the bounds for
              // what needs to be rendered
              collectionGroup.setUseServerPaging(true);
              collectionGroup.setDisplayStart(dataTablesInputs.iDisplayStart);
              collectionGroup.setDisplayLength(dataTablesInputs.iDisplayLength);
          }
  
          // these other params above don't need to stay in the form after this request, but <collectionGroupId>_columnSorts
          // does so that we avoid re-sorting on each request.
          ViewLifecycle.getViewPostMetadata().addComponentPostData(collectionGroupId,
                  UifConstants.IdSuffixes.COLUMN_SORTS, newColumnSorts);
      }
  
      /**
       * Extract the sorting information from the DataTablesInputs into a more generic form.
       *
       * @param form object containing the view's data
       * @param view posted view containing the collection
       * @param dataTablesInputs the parsed request data from dataTables
       * @return the List of ColumnSort elements representing the requested sort columns, types, and directions
       */
      private static List<ColumnSort> buildColumnSorts(View view, ViewModel form, DataTablesInputs dataTablesInputs,
              CollectionGroup collectionGroup) {
          int[] sortCols = dataTablesInputs.iSortCol_; // cols being sorted on (for multi-col sort)
          boolean[] sortable = dataTablesInputs.bSortable_; // which columns are sortable
          String[] sortDir = dataTablesInputs.sSortDir_; // direction to sort
  
          // parse table options to gather the sort types
          String aoColumnDefsValue = (String) form.getViewPostMetadata().getComponentPostData(collectionGroup.getId(),
                  UifConstants.TableToolsKeys.AO_COLUMN_DEFS);
  
          JsonArray jsonColumnDefs = null;
          if (!StringUtils.isEmpty(aoColumnDefsValue)) { // we'll parse this using a JSON library to make things simpler
             // function definitions are not allowed in JSON
             aoColumnDefsValue = aoColumnDefsValue.replaceAll("function\\([^)]*\\)\\s*\\{[^}]*\\}", "\"REDACTED\"");
             JsonReader jsonReader = Json.createReader(new StringReader(aoColumnDefsValue));
             jsonColumnDefs = jsonReader.readArray();
         }
 
         List<ColumnSort> columnSorts = new ArrayList<ColumnSort>(sortCols.length);
 
         for (int sortColsIndex = 0; sortColsIndex < sortCols.length; sortColsIndex++) {
             int sortCol = sortCols[sortColsIndex]; // get the index of the column being sorted on
 
             if (sortable[sortCol]) {
                 String sortType = getSortType(jsonColumnDefs, sortCol);
                 ColumnSort.Direction sortDirection = ColumnSort.Direction.valueOf(sortDir[sortColsIndex].toUpperCase());
                 columnSorts.add(new ColumnSort(sortCol, sortDirection, sortType));
             }
         }
 
         return columnSorts;
     }
 
     /**
      * Get the sort type string from the parsed column definitions object.
      *
      * @param jsonColumnDefs the JsonArray representation of the aoColumnDefs property from the RichTable template
      * options
      * @param sortCol the index of the column to get the sort type for
      * @return the name of the sort type specified in the template options, or the default of "string" if none is
      * found.
      */
     private static String getSortType(JsonArray jsonColumnDefs, int sortCol) {
         String sortType = "string"; // default to string if nothing is spec'd
 
         if (jsonColumnDefs != null) {
             JsonObject column = jsonColumnDefs.getJsonObject(sortCol);
 
             if (column.containsKey("sType")) {
                 sortType = column.getString("sType");
             }
         }
         return sortType;
     }
 
     /**
      * Sort the given modelCollection (in place) according to the specified columnSorts.
      *
      * <p>Not all columns will necessarily be directly mapped to the modelCollection, so the collectionGroup and view
      * are available as well for use in calculating those other column values.  However, if all the columns are in fact
      * mapped to the elements of the modelCollection, subclasses should be able to easily override this method to
      * provide custom sorting logic.</p>
      *
      * <p>
      * Create an index array and sort that. The array slots represents the slots in the modelCollection, and
      * the values are indices to the elements in the modelCollection.  At the end, we'll re-order the
      * modelCollection so that the elements are in the collection slots that correspond to the array locations.
      *
      * A small example may be in order.  Here's the incoming modelCollection:
      *
      * modelCollection = { "Washington, George", "Adams, John", "Jefferson, Thomas", "Madison, James" }
      *
      * Initialize the array with its element references all matching initial positions in the modelCollection:
      *
      * reSortIndices = { 0, 1, 2, 3 }
      *
      * After doing our sort in the array (where we sort indices based on the values in the modelCollection):
      *
      * reSortIndices = { 1, 2, 3, 0 }
      *
      * Then, we go back and apply that ordering to the modelCollection:
      *
      * modelCollection = { "Adams, John", "Jefferson, Thomas", "Madison, James", "Washington, George" }
      *
      * Why do it this way instead of just sorting the modelCollection directly?  Because we may need to know
      * the original index of the element e.g. for the auto sequence column.
      * </p>
      *
      * @param modelCollection the collection to sort
      * @param oldColumnSorts the sorting that reflects the current state of the collection
      * @param newColumnSorts the sorting to apply to the collection
      * @param collectionGroup the CollectionGroup that is being rendered
      * @param form object containing the view's data
      * @param view the view
      */
     protected static void applyTableJsonSort(final List<Object> modelCollection, List<ColumnSort> oldColumnSorts,
             final List<ColumnSort> newColumnSorts, final CollectionGroup collectionGroup, ViewModel form,
             final View view) {
 
         boolean isCollectionEmpty = CollectionUtils.isEmpty(modelCollection);
         boolean isSortingSpecified = !CollectionUtils.isEmpty(newColumnSorts);
         boolean isSortOrderChanged = newColumnSorts != oldColumnSorts && !newColumnSorts.equals(oldColumnSorts);
 
         if (!isCollectionEmpty && isSortingSpecified && isSortOrderChanged) {
             Integer[] sortIndices = new Integer[modelCollection.size()];
             for (int i = 0; i < sortIndices.length; i++) {
                 sortIndices[i] = i;
             }
 
             MultiColumnComparator comparator = new MultiColumnComparator(modelCollection, collectionGroup,
                     newColumnSorts, form, view);
             Arrays.sort(sortIndices, comparator);
 
             // apply the sort to the modelCollection
             Object[] sorted = new Object[sortIndices.length];
             for (int i = 0; i < sortIndices.length; i++) {
                 sorted[i] = modelCollection.get(sortIndices[i]);
             }
 
             for (int i = 0; i < sorted.length; i++) {
                 modelCollection.set(i, sorted[i]);
             }
         }
     }
 
     /**
      * Input command processor for supporting DataTables server-side processing.
      *
      * @see <a href="http://datatables.net/usage/server-side">http://datatables.net/usage/server-side</a>
      */
     public static class DataTablesInputs {
         private static final String DISPLAY_START = "iDisplayStart";
         private static final String DISPLAY_LENGTH = "iDisplayLength";
         private static final String COLUMNS = "iColumns";
         private static final String REGEX = "bRegex";
         private static final String REGEX_PREFIX = "bRegex_";
         private static final String SORTABLE_PREFIX = "bSortable_";
         private static final String SORTING_COLS = "iSortingCols";
         private static final String SORT_COL_PREFIX = "iSortCol_";
         private static final String SORT_DIR_PREFIX = "sSortDir_";
         private static final String DATA_PROP_PREFIX = "mDataProp_";
         private static final String ECHO = "sEcho";
 
         private final int iDisplayStart, iDisplayLength, iColumns, iSortingCols, sEcho;
 
         // TODO: All search related options are commented out of this class.
         // If we implement search for datatables we'll want to re-activate that code to capture the configuration
         // values from the request
 
         //        private final String sSearch;
         //        private final Pattern patSearch;
 
         private final boolean bRegex;
         private final boolean[] /*bSearchable_,*/ bRegex_, bSortable_;
         private final String[] /*sSearch_,*/ sSortDir_, mDataProp_;
 
         //        private final Pattern[] patSearch_;
 
         private final int[] iSortCol_;
 
         public DataTablesInputs(HttpServletRequest request) {
             String s;
             iDisplayStart = (s = request.getParameter(DISPLAY_START)) == null ? 0 : Integer.parseInt(s);
             iDisplayLength = (s = request.getParameter(DISPLAY_LENGTH)) == null ? 0 : Integer.parseInt(s);
             iColumns = (s = request.getParameter(COLUMNS)) == null ? 0 : Integer.parseInt(s);
             bRegex = (s = request.getParameter(REGEX)) == null ? false : new Boolean(s);
 
             //            patSearch = (sSearch = request.getParameter("sSearch")) == null
             //                    || !bRegex ? null : Pattern.compile(sSearch);
             //            bSearchable_ = new boolean[iColumns];
             //            sSearch_ = new String[iColumns];
             //            patSearch_ = new Pattern[iColumns];
 
             bRegex_ = new boolean[iColumns];
             bSortable_ = new boolean[iColumns];
 
             for (int i = 0; i < iColumns; i++) {
 
                 //                bSearchable_[i] = (s = request.getParameter("bSearchable_" + i)) == null ? false
                 //                        : new Boolean(s);
 
                 bRegex_[i] = (s = request.getParameter(REGEX_PREFIX + i)) == null ? false : new Boolean(s);
 
                 //                patSearch_[i] = (sSearch_[i] = request.getParameter("sSearch_"
                 //                        + i)) == null
                 //                        || !bRegex_[i] ? null : Pattern.compile(sSearch_[i]);
 
                 bSortable_[i] = (s = request.getParameter(SORTABLE_PREFIX + i)) == null ? false : new Boolean(s);
             }
 
             iSortingCols = (s = request.getParameter(SORTING_COLS)) == null ? 0 : Integer.parseInt(s);
             iSortCol_ = new int[iSortingCols];
             sSortDir_ = new String[iSortingCols];
 
             for (int i = 0; i < iSortingCols; i++) {
                 iSortCol_[i] = (s = request.getParameter(SORT_COL_PREFIX + i)) == null ? 0 : Integer.parseInt(s);
                 sSortDir_[i] = request.getParameter(SORT_DIR_PREFIX + i);
             }
 
             mDataProp_ = new String[iColumns];
 
             for (int i = 0; i < iColumns; i++) {
                 mDataProp_[i] = request.getParameter(DATA_PROP_PREFIX + i);
             }
 
             sEcho = (s = request.getParameter(ECHO)) == null ? 0 : Integer.parseInt(s);
         }
 
         @Override
         public String toString() {
             StringBuilder sb = new StringBuilder(super.toString());
             sb.append("\n\t" + DISPLAY_START + " = ");
             sb.append(iDisplayStart);
             sb.append("\n\t" + DISPLAY_LENGTH + " = ");
             sb.append(iDisplayLength);
             sb.append("\n\t" + COLUMNS + " = ");
             sb.append(iColumns);
 
             //            sb.append("\n\tsSearch = ");
             //            sb.append(sSearch);
 
             sb.append("\n\t" + REGEX + " = ");
             sb.append(bRegex);
 
             for (int i = 0; i < iColumns; i++) {
 
                 //                sb.append("\n\tbSearchable_").append(i).append(" = ");
                 //                sb.append(bSearchable_[i]);
 
                 //                sb.append("\n\tsSearch_").append(i).append(" = ");
                 //                sb.append(sSearch_[i]);
 
                 sb.append("\n\t").append(REGEX_PREFIX).append(i).append(" = ");
                 sb.append(bRegex_[i]);
                 sb.append("\n\t").append(SORTABLE_PREFIX).append(i).append(" = ");
                 sb.append(bSortable_[i]);
             }
 
             sb.append("\n\t").append(SORTING_COLS);
             sb.append(iSortingCols);
 
             for (int i = 0; i < iSortingCols; i++) {
                 sb.append("\n\t").append(SORT_COL_PREFIX).append(i).append(" = ");
                 sb.append(iSortCol_[i]);
                 sb.append("\n\t").append(SORT_DIR_PREFIX).append(i).append(" = ");
                 sb.append(sSortDir_[i]);
             }
 
             for (int i = 0; i < iColumns; i++) {
                 sb.append("\n\t").append(DATA_PROP_PREFIX).append(i).append(" = ");
                 sb.append(mDataProp_[i]);
             }
 
             sb.append("\n\t" + ECHO + " = ");
             sb.append(sEcho);
 
             return sb.toString();
         }
     }
 }