/**
 * A sorter for TableModels. The sorter has a model (conforming to TableModel)
 * and itself implements TableModel. TableSorter does not store or copy
 * the data in the TableModel, instead it maintains an array of
 * integers which it keeps the same size as the number of rows in its
 * model. When the model changes it notifies the sorter that something
 * has changed eg. "rowsAdded" so that its internal array of integers
 * can be reallocated. As requests are made of the sorter (like
 * getValueAt(row, col) it redirects them to its model via the mapping
 * array. That way the TableSorter appears to hold another copy of the table
 * with the rows in a different order. The sorting algorthm used is stable
 * which means that it does not move around rows when its comparison
 * function returns 0 to denote that they are equivalent.
 *
 * @version 1.5 12/17/97
 * @author Philip Milne, modified by me
 *
 */

import java.util.*;

import javax.swing.JTable;
import javax.swing.table.TableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumnModel;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.UIManager;

import javax.swing.event.TableModelEvent;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.*;
import javax.swing.table.*;

public class TableSorter extends TableMap
{
    private final boolean debug = false;

    public static final int UP = 0;
    public static final int DOWN = 1;

    public static final ImageIcon upIcon= new ImageIcon("images/uparrow.gif");
    public static final ImageIcon downIcon= new ImageIcon("images/downarrow.gif");

    private int[]       indexes;
    private Vector    sortingColumns = new Vector();
    private boolean   ascending = true;
    private int       compares;

    //For the table column header sort icon
    int       sortOrder = DOWN; //expected sort order
    int       sortColumn = -1;  //sort which model column
    int       sortViewColumn = -1; //sort which view column

    public TableSorter(TableModel model)
    {
        super(model);
        reallocateIndexes();
    }

    public void setModel(TableModel model)
    {
        super.setModel(model);
        reallocateIndexes();
    }

    public int[] getIndices() { return indexes; }
    // The mapping only affects the contents of the data rows.
    // Pass all requests to these rows through the mapping array: "indexes".
    public Object getValueAt(int aRow, int aColumn)
    {
        checkModel();
        return model.getValueAt(indexes[aRow], aColumn);
    }

    public void setValueAt(Object aValue, int aRow, int aColumn)
    {
        checkModel();
        model.setValueAt(aValue, indexes[aRow], aColumn);
    }

    public void tableChanged(TableModelEvent e)
    {
        //System.out.println("Sorter: tableChanged");
        reallocateIndexes();
        super.tableChanged(e);
    }

    // Add a mouse listener to the Table to trigger a table sort
    // when a column heading is clicked in the JTable.
    public void addMouseListenerToHeaderInTable(JTable table)
    {
        final TableSorter sorter = this;
        final JTable tableView = table;
        //turn off this, otherwise, it would highlight the column.
        //tableView.setColumnSelectionAllowed(false);
        MouseAdapter listMouseListener = new MouseAdapter()
        {
            public void mouseClicked(MouseEvent e)
            {
                TableColumnModel columnModel = tableView.getColumnModel();
                int viewColumn = columnModel.getColumnIndexAtX(e.getX());
                debug("=======================================");
                debug("view column=" + viewColumn);
                int column = tableView.convertColumnIndexToModel(viewColumn);
                debug("model column=" + column);
                debug("old sorting column=" + sortColumn);
                debug("old sorting view column=" + sortViewColumn);
                debug("old sorting order=" + sortOrder);
                if (e.getClickCount() == 1 && viewColumn != -1)
                {
                    // jump between columns, ascending and descending
                    sorter.sortByColumn(column, (sortColumn != column) || (sortOrder == DOWN));
                    sortColumn = column;//now memorize this sorting column

                    // clear all column headers. Since we don't know which one
                    // has the sorting flag, so clear them all.
                    // don't try to memorize that flag(view column) because
                    // users can switch view columns without notifying you!
                    JLabel picLabel;
                    int len = columnModel.getColumnCount();
                    for (int i=0; i<len; i++)
                    {
                        picLabel = new JLabel(tableView.getColumnName(i), JLabel.CENTER);
                        picLabel.setBorder(UIManager.getBorder("TableHeader.cellBorder"));
                        picLabel.setHorizontalTextPosition(JLabel.CENTER);
                        columnModel.getColumn(i).setHeaderValue(picLabel);
                    }

                    // now set the correct icon for the column
                    String columntitle = "<html><font color=red>" +
                                         tableView.getColumnName(viewColumn) + "</font></html>";
                    if (sortViewColumn != viewColumn)
                    {
                        picLabel = new JLabel(columntitle, downIcon, JLabel.CENTER);
                        sortOrder = UP;
                    }
                    else if (sortOrder == DOWN)
                    {
                        picLabel = new JLabel(columntitle, downIcon, JLabel.CENTER);
                        sortOrder = UP;
                    }
                    else
                    {
                        picLabel = new JLabel(columntitle, upIcon, JLabel.CENTER);
                        sortOrder = DOWN;
                    }
                    picLabel.setBorder(UIManager.getBorder("TableHeader.cellBorder"));
                    picLabel.setHorizontalTextPosition(JLabel.LEFT);
                    tableView.getColumnModel().getColumn(viewColumn).setHeaderValue(picLabel);
                    sortViewColumn = viewColumn;
                    // these two lines are working, so we need to figure out the height
                    tableView.getTableHeader().setPreferredSize(new java.awt.Dimension(0,30));
                    tableView.getTableHeader().resizeAndRepaint();
                    // Setting the preferred size on the column header renderer will not
                    // work when you are using rowheaders and corner components in the
                    // containing scrollpane. If the corner component is taller than your
                    // table header, it will not display fully. So instead, set the preferred
                    // size of the viewport containing your table/column header like this:
                    // scrollpane.getColumnHeader().setPreferredSize(new java.awt.Dimension(0, 100));
                    // however, for now, we just set this:
                    // JLabel l=(JLabel)tableView.getColumnModel().getColumn(viewColumn).getHeaderRenderer();
                    // l.setPreferredSize(new java.awt.Dimension(0,100));
                    // however, it's working for this app, since
                    // System.out.println(tableView.getColumnModel().getColumn(viewColumn).getHeaderRenderer().getClass().getName());
                    // returns
                    // lib.swing.table.JComponentTableCellRenderer

                }
            }
        };
        JTableHeader th = tableView.getTableHeader();
        th.addMouseListener(listMouseListener);
    }

    private final void debug(String s)
    {
        if (debug == true && s != null && !s.trim().equals(""))
            System.out.println("TableSorter: -- " + s);
    }

    // private implementation starts here
    // ======================================================================
    private void checkModel()
    {
        if (indexes.length != model.getRowCount())
        {
            System.err.println("Sorter not informed of a change in model.");
        }
    }

    private void reallocateIndexes()
    {
        int rowCount = model.getRowCount();

        // Set up a new array of indexes with the right number of elements
        // for the new data model.
        indexes = new int[rowCount];

        // Initialise with the identity mapping.
        for (int row = 0; row < rowCount; row++)
        {
            indexes[row] = row;
        }
    }

    //sort starts from here. The following functions are called one inside another.
    private void sortByColumn(int column)
    {
        sortByColumn(column, true);
    }

    private void sortByColumn(int column, boolean ascending)
    {
        this.ascending = ascending;
        sortingColumns.removeAllElements();
        sortingColumns.addElement(new Integer(column));
        sort(this);
        super.tableChanged(new TableModelEvent(this));
    }

    private void sort(Object sender)
    {
        checkModel();
        compares = 0;
        shuttlesort((int[])indexes.clone(), indexes, 0, indexes.length);
    }

    // This is a home-grown implementation which we have not had time
    // to research - it may perform poorly in some circumstances. It
    // requires twice the space of an in-place algorithm and makes
    // NlogN assigments shuttling the values between the two
    // arrays. The number of compares appears to vary between N-1 and
    // NlogN depending on the initial order but the main reason for
    // using it here is that, unlike qsort, it is stable.
    private void shuttlesort(int from[], int to[], int low, int high) {
        if (high - low < 2) return;

        int middle = (low + high)/2;
        shuttlesort(to, from, low, middle);
        shuttlesort(to, from, middle, high);

        int p = low;
        int q = middle;

        /* This is an optional short-cut; at each recursive call,
        check to see if the elements in this subset are already
        ordered.  If so, no further comparisons are needed; the
        sub-array can just be copied.  The array must be copied rather
        than assigned otherwise sister calls in the recursion might
        get out of sinc.  When the number of elements is three they
        are partitioned so that the first set, [low, mid), has one
        element and and the second, [mid, high), has two. We skip the
        optimisation when the number of elements is three or less as
        the first compare in the normal merge will produce the same
        sequence of steps. This optimisation seems to be worthwhile
        for partially ordered lists but some analysis is needed to
        find out how the performance drops to Nlog(N) as the initial
        order diminishes - it may drop very quickly.  */
        if (high - low >= 4 && compare(from[middle-1], from[middle]) <= 0)
        {
            for (int i = low; i < high; i++)
            {
                to[i] = from[i];
            }
            return;
        }

        // A normal merge.
        for (int i = low; i < high; i++) {
            if (q >= high || (p < middle && compare(from[p], from[q]) <= 0))
            {
                to[i] = from[p++];
            }
            else
            {
                to[i] = from[q++];
            }
        }
    }

    private int compare(int row1, int row2) {
        compares++;
        for (int level = 0; level < sortingColumns.size(); level++) {
            Integer column = (Integer)sortingColumns.elementAt(level);
            int result = compareRowsByColumn(row1, row2, column.intValue());
            if (result != 0) {
                return ascending ? result : -result;
            }
        }
        return 0;
    }

    private int compareRowsByColumn(int row1, int row2, int column)
    {
        Class type = model.getColumnClass(column);
        TableModel data = model;

        // Check for nulls.
        Object o1 = data.getValueAt(row1, column);
        Object o2 = data.getValueAt(row2, column);

        // If both values are null, return 0.
        if (o1 == null && o2 == null) return 0;
        // Define null less than everything.
        else if (o1 == null) return -1;
        else if (o2 == null) return 1;

        /*
         * We copy all returned values from the getValue call in case an
         * optimised model is reusing one object to return many values.
         * The Number subclasses in the JDK are immutable and so will not
         * be used in this way but other subclasses of Number might want
         * to do this to save space and avoid unnecessary heap allocation.
         */
        if (type.getSuperclass() == java.lang.Number.class)
        {
            Number n1 = (Number)data.getValueAt(row1, column);
            double d1 = n1.doubleValue();
            Number n2 = (Number)data.getValueAt(row2, column);
            double d2 = n2.doubleValue();

            if (d1 < d2)  return -1;
            else if (d1 > d2) return 1;
            else return 0;
        }
        else if (type == java.util.Date.class)
        {
            Date d1 = (Date)data.getValueAt(row1, column);
            long n1 = d1.getTime();
            Date d2 = (Date)data.getValueAt(row2, column);
            long n2 = d2.getTime();

            if (n1 < n2) return -1;
            else if (n1 > n2) return 1;
            else return 0;
        }
        else if (type == String.class)
        {
            String s1 = (String)data.getValueAt(row1, column);
            String s2    = (String)data.getValueAt(row2, column);
            int result = s1.compareTo(s2);

            if (result < 0) return -1;
            else if (result > 0) return 1;
            else return 0;
        }
        else if (type == Boolean.class)
        {
            Boolean bool1 = (Boolean)data.getValueAt(row1, column);
            boolean b1 = bool1.booleanValue();
            Boolean bool2 = (Boolean)data.getValueAt(row2, column);
            boolean b2 = bool2.booleanValue();

            if (b1 == b2) return 0;
            else if (b1) return 1; // Define false < true
            else return -1;
        }
        else
        {
            Object v1 = data.getValueAt(row1, column);
            String s1 = v1.toString();
            Object v2 = data.getValueAt(row2, column);
            String s2 = v2.toString();
            int result = s1.compareTo(s2);

            if (result < 0) return -1;
            else if (result > 0) return 1;
            else return 0;
        }
    }
}