/*
    * Copyright 2004-2008 the Seasar Foundation and the Others.
    *
    * Licensed 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.seasar.uruma.viewer;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import org.eclipse.jface.viewers.IBaseLabelProvider;
  import org.eclipse.jface.viewers.ITableLabelProvider;
  import org.eclipse.jface.viewers.TableViewer;
  import org.eclipse.jface.viewers.Viewer;
  import org.eclipse.jface.viewers.ViewerComparator;
  import org.eclipse.swt.SWT;
  import org.eclipse.swt.events.SelectionEvent;
  import org.eclipse.swt.events.SelectionListener;
  import org.eclipse.swt.widgets.Table;
  import org.eclipse.swt.widgets.TableColumn;
  
  /**
   * {@link TableViewer} 用の汎用ソートクラスです。<br />
   * 
   * @author y-komori
   */
  public class GenericTableViewerComparator extends ViewerComparator {
      private Table table;
  
      private Map<TableColumn, Integer> columnMap = new HashMap<TableColumn, Integer>();
  
      private TableColumn sortKey;
  
      private SortingState sortingState = SortingState.NONE;
  
      /**
       * {@link GenericTableViewerComparator} を構築します。<br />
       */
      public GenericTableViewerComparator() {
          super(new StringAndNumberComparator());
      }
  
      protected void setupColumnMap(final TableViewer viewer) {
          this.table = viewer.getTable();
          TableColumn[] columns = table.getColumns();
          if (columns.length == 0) {
              return;
          }
  
          for (int i = 0; i < columns.length; i++) {
              columnMap.put(columns[i], i);
  
              columns[i].addSelectionListener(new SelectionListener() {
                  public void widgetDefaultSelected(final SelectionEvent e) {
                  }
  
                  public void widgetSelected(final SelectionEvent e) {
                      setSortKey((TableColumn) e.widget);
                      viewer.setInput(viewer.getInput());
                  }
              });
          }
  
          sortKey = columns[0];
      }
  
      /*
       * @see org.eclipse.jface.viewers.ViewerComparator#compare(org.eclipse.jface.viewers.Viewer,
       *      java.lang.Object, java.lang.Object)
       */
      @Override
      public int compare(final Viewer viewer, final Object e1, final Object e2) {
          TableViewer tableViewer = (TableViewer) viewer;
  
          if (this.table == null) {
              setupColumnMap(tableViewer);
          }
  
          int cat1 = category(e1);
          int cat2 = category(e2);
  
          if (cat1 != cat2) {
              return cat1 - cat2;
          }
  
          Integer sortColumn = columnMap.get(sortKey);
          if (sortColumn != null) {
              int result = doCompare(tableViewer, e1, e2, sortColumn.intValue());
  
             if (sortingState == SortingState.ASCENDING) {
                 return result;
             } else if (sortingState == SortingState.DESCENDING) {
                 return result * (-1);
             } else {
                 return 0;
             }
         } else {
             return 0;
         }
     }
 
     /**
      * モデルオブジェクトの比較を行います。<br />
      * 比較方法をカスタマイズする場合、サブクラスで本メソッドをオーバーライドしてください。<br />
      * 
      * @param viewer
      *            {@link TableViewer} オブジェクト
      * @param e1
      *            比較対象1
      * @param e2
      *            比較対象2
      * @param sortColumn
      *            ソート対象のカラム番号
      * @return 比較結果
      */
     protected int doCompare(final TableViewer viewer, final Object e1,
             final Object e2, final int sortColumn) {
         IBaseLabelProvider baseLabelProvider = viewer.getLabelProvider();
 
         String value1 = "";
         String value2 = "";
         if (baseLabelProvider instanceof ITableLabelProvider) {
             ITableLabelProvider prov = (ITableLabelProvider) baseLabelProvider;
             value1 = prov.getColumnText(e1, sortColumn);
             value2 = prov.getColumnText(e2, sortColumn);
         } else {
             value1 = e1.toString();
             value2 = e2.toString();
         }
 
         if (value1 == null) {
             value1 = "";
         }
         if (value2 == null) {
             value2 = "";
         }
 
         return getComparator().compare(value1, value2);
     }
 
     /**
      * ソートキーとなるカラムを設定します。<br />
      * ソート順は呼び出すたびに反転します。
      * 
      * @param tableColumn
      *            ソートキーとなる {@link TableColumn} オブジェクト
      */
     public void setSortKey(final TableColumn tableColumn) {
         if ((tableColumn != null) && !tableColumn.isDisposed()) {
             sortKey = tableColumn;
 
             if (sortingState == SortingState.DESCENDING) {
                 sortingState = SortingState.ASCENDING;
                 table.setSortColumn(sortKey);
                 table.setSortDirection(SWT.UP);
             } else if (sortingState == SortingState.ASCENDING) {
                 sortingState = SortingState.NONE;
                 table.setSortColumn(null);
                 table.setSortDirection(SWT.NONE);
             } else if (sortingState == SortingState.NONE) {
                 sortingState = SortingState.DESCENDING;
                 table.setSortColumn(sortKey);
                 table.setSortDirection(SWT.DOWN);
             }
         }
     }
 }