/**
    * This file Copyright (c) 2003-2014 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.cms.gui.controlx.list;
  
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * @author Sameer Charles $Id$
   */
  public abstract class AbstractListModel implements ListModel {
  
      private static Logger log = LoggerFactory.getLogger(AbstractListModel.class);
  
      /**
       * sort or group by order
       */
      public static final String DESCENDING = "DESC";
  
      /**
       * sort or group by order
       */
      public static final String ASCENDING = "ASC";
  
      /**
       * sort by field name
       */
      protected String sortBy;
  
      /**
       * sort by order
       */
      protected String sortByOrder;
  
      /**
       * group by field name
       */
      protected String groupBy;
  
      /**
       * group by order
       */
      protected String groupByOrder;
  
      /**
       * Used to get values out of the nodes/objects handled by the list
       */
      private ValueProvider valueProvider;
  
      /**
       * this must be implemented by implementing classes
       * @return Iterator over found records
       * @see ListModelIterator
       */
      @Override
      public ListModelIterator getListModelIterator() {
          try {
              Collection items = getResult();
             items = doSort(items);
             return createIterator(items);
         }
         catch (Exception re) {
             log.error("can't create the list model iterator, will return an empty list", re);
             return new ListModelIteratorImpl(this, new ArrayList());
         }
     }
 
     @Override
     public Iterator iterator() {
         return getListModelIterator();
     }
 
     /**
      * @return the collection of the items passed to the iterator
      */
     protected abstract Collection getResult() throws Exception;
 
     /**
      * Create the iterator
      * @param items
      * @return
      */
     protected ListModelIterator createIterator(Collection items) {
         if(!(items instanceof List)){
             throw new RuntimeException("items must be a List");
         }
         return new ListModelIteratorImpl(this, (List) items);
     }
 
     /**
      * set sort by field
      * @param name
      */
     @Override
     public void setSortBy(String name) {
         this.sortBy = name;
     }
 
     /**
      * set sort by field and order ('ASCENDING' | 'DESCENDING')
      * @param name
      * @param order
      */
     @Override
     public void setSortBy(String name, String order) {
         this.sortBy = name;
         this.sortByOrder = order;
     }
 
     /**
      * set group by field
      * @param name
      */
     @Override
     public void setGroupBy(String name) {
         this.groupBy = name;
     }
 
     /**
      * set group by field and order ('ASCENDING' | 'DESCENDING')
      * @param name
      * @param order
      */
     @Override
     public void setGroupBy(String name, String order) {
         this.groupBy = name;
         this.groupByOrder = order;
     }
 
     /**
      * get sort on field name
      * @return String field name
      */
     @Override
     public String getSortBy() {
         return this.sortBy;
     }
 
     /**
      * get sort by ordering
      * @return order ('ASCENDING' | 'DESCENDING')
      */
     @Override
     public String getSortByOrder() {
         return this.sortByOrder;
     }
 
     /**
      * get group on field name
      * @return String field name
      */
     @Override
     public String getGroupBy() {
         return this.groupBy;
     }
 
     /**
      * get group by ordering
      * @return order ('ASCENDING' | 'DESCENDING')
      */
     @Override
     public String getGroupByOrder() {
         return this.groupByOrder;
     }
 
     /**
      * sort
      * @param collection
      * @return sorted collection
      */
     protected Collection doSort(Collection collection) {
         if(!(collection instanceof List)){
             log.warn("can sort only collections of type {} but got a {}", List.class, collection.getClass());
             return collection;
         }
         List list = (List) collection;
         if (StringUtils.isNotEmpty(this.getGroupBy())) {
             ListComparator comparator = newComparator();
             comparator.setSortBy(this.getGroupBy());
             comparator.setOrder(this.getGroupByOrder());
             Collections.sort(list, comparator);
         }
         if (StringUtils.isNotEmpty(this.getGroupBy()) && StringUtils.isNotEmpty(this.getSortBy())) { // sub sort
             ListComparator comparator = newComparator();
             comparator.setPreSort(this.getGroupBy());
             comparator.setSortBy(this.getSortBy());
             comparator.setOrder(this.getSortByOrder());
             Collections.sort(list, comparator);
         }
         if (StringUtils.isEmpty(this.getGroupBy()) && StringUtils.isNotEmpty(this.getSortBy())) {
             ListComparator comparator = newComparator();
             comparator.setSortBy(this.getSortBy());
             comparator.setOrder(this.getSortByOrder());
             Collections.sort(list, comparator);
         }
         return list;
     }
 
     protected ListComparator newComparator() {
         return new ListComparator();
     }
 
     /**
      * @param valueProvider the valueProvider to set
      */
     public void setValueProvider(ValueProvider valueProvider) {
         this.valueProvider = valueProvider;
     }
 
     /**
      * @return the valueProvider
      */
     public ValueProvider getValueProvider() {
         if (valueProvider == null) {
             valueProvider = DefaultValueProvider.getInstance();
         }
         return valueProvider;
     }
 
     /**
      * Use by the list iterator to resolve the id
      */
     protected String resolveId(int index, Object value){
         return Integer.toString(index);
     }
 
     /**
      * Does simple or sub ordering
      */
     protected class ListComparator implements Comparator {
 
         private String preSort;
 
         private String sortBy;
 
         private String order;
 
         @Override
         public int compare(Object object, Object object1) {
             if (StringUtils.isNotEmpty(this.sortBy) && StringUtils.isEmpty(this.preSort)) {
                 return this.sort(object, object1);
             }
             else if (StringUtils.isNotEmpty(this.sortBy) && StringUtils.isNotEmpty(this.preSort)) {
                 return this.subSort(object, object1);
             }
             return 0;
         }
 
         /**
          * group by
          * @param object to be compared
          * @param object1 to be compared
          */
         protected int sort(Object object, Object object1) {
             Comparable firstKey = (Comparable) getValueProvider().getValue(this.sortBy, object);
             Comparable secondKey = (Comparable) getValueProvider().getValue(this.sortBy, object1);
             if (this.getOrder().equalsIgnoreCase(ASCENDING)) {
                 return firstKey.compareTo(secondKey);
             }
 
             return secondKey.compareTo(firstKey);
         }
 
         /**
          * sub sort
          * @param object to be compared
          * @param object1 to be compared
          */
         protected int subSort(Object object, Object object1) {
             String firstKey = (String) getValueProvider().getValue(this.preSort, object);
             String secondKey = (String) getValueProvider().getValue(this.preSort, object1);
             Comparable subSortFirstKey = (Comparable) getValueProvider().getValue(this.sortBy, object);
             Comparable subSortSecondKey = (Comparable) getValueProvider().getValue(this.sortBy, object1);
             if (firstKey.equalsIgnoreCase(secondKey)) {
                 if (this.getOrder().equalsIgnoreCase(ASCENDING)) {
                     return subSortFirstKey.compareTo(subSortSecondKey);
                 }
                 return subSortSecondKey.compareTo(subSortFirstKey);
             }
             return -1;
         }
 
         public String getPreSort() {
             return preSort;
         }
 
         public void setPreSort(String preSort) {
             this.preSort = preSort;
         }
 
         public String getSortBy() {
             return sortBy;
         }
 
         public void setSortBy(String sortBy) {
             this.sortBy = sortBy;
         }
 
         public String getOrder() {
             if (order == null) {
                 return ASCENDING;
             }
             return order;
         }
 
         public void setOrder(String order) {
             this.order = order;
         }
 
     }
 }