/*
 * Jalview - A Sequence Alignment Editor and Viewer (2.11.1.4)
 * Copyright (C) 2021 The Jalview Authors
 * 
 * This file is part of Jalview.
 * 
 * Jalview is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License 
 * as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *  
 * Jalview is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty 
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
 * PURPOSE.  See the GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
 * The Jalview Authors are detailed in the 'AUTHORS' file.
 */
package jalview.util;

import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.swing.Icon;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumnModel;
import javax.swing.table.TableModel;

/**
 * TableSorter is a decorator for TableModels; adding sorting functionality to a
 * supplied TableModel. TableSorter does not store or copy the data in its
 * TableModel; instead it maintains a map from the row indexes of the view to
 * the row indexes of the model. As requests are made of the sorter (like
 * getValueAt(row, col)) they are passed to the underlying model after the row
 * numbers have been translated via the internal mapping array. This way, the
 * TableSorter appears to hold another copy of the table with the rows in a
 * different order.
 * <p/>
 * TableSorter registers itself as a listener to the underlying model, just as
 * the JTable itself would. Events recieved from the model are examined,
 * sometimes manipulated (typically widened), and then passed on to the
 * TableSorter's listeners (typically the JTable). If a change to the model has
 * invalidated the order of TableSorter's rows, a note of this is made and the
 * sorter will resort the rows the next time a value is requested.
 * <p/>
 * When the tableHeader property is set, either by using the setTableHeader()
 * method or the two argument constructor, the table header may be used as a
 * complete UI for TableSorter. The default renderer of the tableHeader is
 * decorated with a renderer that indicates the sorting status of each column.
 * In addition, a mouse listener is installed with the following behavior:
 * <ul>
 * <li>Mouse-click: Clears the sorting status of all other columns and advances
 * the sorting status of that column through three values: {NOT_SORTED,
 * ASCENDING, DESCENDING} (then back to NOT_SORTED again).
 * <li>SHIFT-mouse-click: Clears the sorting status of all other columns and
 * cycles the sorting status of the column through the same three values, in the
 * opposite order: {NOT_SORTED, DESCENDING, ASCENDING}.
 * <li>CONTROL-mouse-click and CONTROL-SHIFT-mouse-click: as above except that
 * the changes to the column do not cancel the statuses of columns that are
 * already sorting - giving a way to initiate a compound sort.
 * </ul>
 * <p/>
 * This is a long overdue rewrite of a class of the same name that first
 * appeared in the swing table demos in 1997.
 * 
 * @author Philip Milne
 * @author Brendon McLean
 * @author Dan van Enckevort
 * @author Parwinder Sekhon
 * @version 2.0 02/27/04
 */

public class TableSorter extends AbstractTableModel
{
  protected TableModel tableModel;

  public static final int DESCENDING = -1;

  public static final int NOT_SORTED = 0;

  public static final int ASCENDING = 1;

  private static Directive EMPTY_DIRECTIVE = new Directive(-1, NOT_SORTED);

  public static final Comparator COMPARABLE_COMAPRATOR = new Comparator()
  {
    public int compare(Object o1, Object o2)
    {
      return ((Comparable) o1).compareTo(o2);
    }
  };

  public static final Comparator LEXICAL_COMPARATOR = new Comparator()
  {
    public int compare(Object o1, Object o2)
    {
      return o1.toString().compareTo(o2.toString());
    }
  };

  private Row[] viewToModel;

  private int[] modelToView;

  private JTableHeader tableHeader;

  private MouseListener mouseListener;

  private TableModelListener tableModelListener;

  private Map columnComparators = new HashMap();

  private List sortingColumns = new ArrayList();

  public TableSorter()
  {
    this.mouseListener = new MouseHandler();
    this.tableModelListener = new TableModelHandler();
  }

  public TableSorter(TableModel tableModel)
  {
    this();
    setTableModel(tableModel);
  }

  public TableSorter(TableModel tableModel, JTableHeader tableHeader)
  {
    this();
    setTableHeader(tableHeader);
    setTableModel(tableModel);
  }

  private void clearSortingState()
  {
    viewToModel = null;
    modelToView = null;
  }

  public TableModel getTableModel()
  {
    return tableModel;
  }

  public void setTableModel(TableModel tableModel)
  {
    if (this.tableModel != null)
    {
      this.tableModel.removeTableModelListener(tableModelListener);
    }

    this.tableModel = tableModel;
    if (this.tableModel != null)
    {
      this.tableModel.addTableModelListener(tableModelListener);
    }

    clearSortingState();
    fireTableStructureChanged();
  }

  public JTableHeader getTableHeader()
  {
    return tableHeader;
  }

  public void setTableHeader(JTableHeader tableHeader)
  {
    if (this.tableHeader != null)
    {
      this.tableHeader.removeMouseListener(mouseListener);
      TableCellRenderer defaultRenderer = this.tableHeader
              .getDefaultRenderer();
      if (defaultRenderer instanceof SortableHeaderRenderer)
      {
        this.tableHeader.setDefaultRenderer(
                ((SortableHeaderRenderer) defaultRenderer).tableCellRenderer);
      }
    }
    this.tableHeader = tableHeader;
    if (this.tableHeader != null)
    {
      this.tableHeader.addMouseListener(mouseListener);
      this.tableHeader.setDefaultRenderer(new SortableHeaderRenderer(
              this.tableHeader.getDefaultRenderer()));
    }
  }

  public boolean isSorting()
  {
    return sortingColumns.size() != 0;
  }

  private Directive getDirective(int column)
  {
    for (int i = 0; i < sortingColumns.size(); i++)
    {
      Directive directive = (Directive) sortingColumns.get(i);
      if (directive.column == column)
      {
        return directive;
      }
    }
    return EMPTY_DIRECTIVE;
  }

  public int getSortingStatus(int column)
  {
    return getDirective(column).direction;
  }

  private void sortingStatusChanged()
  {
    clearSortingState();
    fireTableDataChanged();
    if (tableHeader != null)
    {
      tableHeader.repaint();
    }
  }

  public void setSortingStatus(int column, int status)
  {
    Directive directive = getDirective(column);
    if (directive != EMPTY_DIRECTIVE)
    {
      sortingColumns.remove(directive);
    }
    if (status != NOT_SORTED)
    {
      sortingColumns.add(new Directive(column, status));
    }
    sortingStatusChanged();
  }

  protected Icon getHeaderRendererIcon(int column, int size)
  {
    Directive directive = getDirective(column);
    if (directive == EMPTY_DIRECTIVE)
    {
      return null;
    }
    return new Arrow(directive.direction == DESCENDING, size,
            sortingColumns.indexOf(directive));
  }

  private void cancelSorting()
  {
    sortingColumns.clear();
    sortingStatusChanged();
  }

  public void setColumnComparator(Class type, Comparator comparator)
  {
    if (comparator == null)
    {
      columnComparators.remove(type);
    }
    else
    {
      columnComparators.put(type, comparator);
    }
  }

  protected Comparator getComparator(int column)
  {
    Class columnType = tableModel.getColumnClass(column);
    Comparator comparator = (Comparator) columnComparators.get(columnType);
    if (comparator != null)
    {
      return comparator;
    }
    if (Comparable.class.isAssignableFrom(columnType))
    {
      return COMPARABLE_COMAPRATOR;
    }
    return LEXICAL_COMPARATOR;
  }

  private Row[] getViewToModel()
  {
    if (viewToModel == null)
    {
      int tableModelRowCount = tableModel.getRowCount();
      viewToModel = new Row[tableModelRowCount];
      for (int row = 0; row < tableModelRowCount; row++)
      {
        viewToModel[row] = new Row(row);
      }

      if (isSorting())
      {
        Arrays.sort(viewToModel);
      }
    }
    return viewToModel;
  }

  public int modelIndex(int viewIndex)
  {
    return getViewToModel()[viewIndex].modelIndex;
  }

  private int[] getModelToView()
  {
    if (modelToView == null)
    {
      int n = getViewToModel().length;
      modelToView = new int[n];
      for (int i = 0; i < n; i++)
      {
        modelToView[modelIndex(i)] = i;
      }
    }
    return modelToView;
  }

  // TableModel interface methods

  public int getRowCount()
  {
    return (tableModel == null) ? 0 : tableModel.getRowCount();
  }

  public int getColumnCount()
  {
    return (tableModel == null) ? 0 : tableModel.getColumnCount();
  }

  public String getColumnName(int column)
  {
    return tableModel.getColumnName(column);
  }

  public Class getColumnClass(int column)
  {
    return tableModel.getColumnClass(column);
  }

  public boolean isCellEditable(int row, int column)
  {
    return tableModel.isCellEditable(modelIndex(row), column);
  }

  public Object getValueAt(int row, int column)
  {
    return tableModel.getValueAt(modelIndex(row), column);
  }

  public void setValueAt(Object aValue, int row, int column)
  {
    tableModel.setValueAt(aValue, modelIndex(row), column);
  }

  // Helper classes

  private class Row implements Comparable
  {
    private int modelIndex;

    public Row(int index)
    {
      this.modelIndex = index;
    }

    public int compareTo(Object o)
    {
      int row1 = modelIndex;
      int row2 = ((Row) o).modelIndex;

      for (Iterator it = sortingColumns.iterator(); it.hasNext();)
      {
        Directive directive = (Directive) it.next();
        int column = directive.column;
        Object o1 = tableModel.getValueAt(row1, column);
        Object o2 = tableModel.getValueAt(row2, column);

        int comparison = 0;
        // Define null less than everything, except null.
        if (o1 == null && o2 == null)
        {
          comparison = 0;
        }
        else if (o1 == null)
        {
          comparison = -1;
        }
        else if (o2 == null)
        {
          comparison = 1;
        }
        else
        {
          comparison = getComparator(column).compare(o1, o2);
        }
        if (comparison != 0)
        {
          return directive.direction == DESCENDING ? -comparison
                  : comparison;
        }
      }
      return 0;
    }
  }

  private class TableModelHandler implements TableModelListener
  {
    public void tableChanged(TableModelEvent e)
    {
      // If we're not sorting by anything, just pass the event along.
      if (!isSorting())
      {
        clearSortingState();
        fireTableChanged(e);
        return;
      }

      // If the table structure has changed, cancel the sorting; the
      // sorting columns may have been either moved or deleted from
      // the model.
      if (e.getFirstRow() == TableModelEvent.HEADER_ROW)
      {
        cancelSorting();
        fireTableChanged(e);
        return;
      }

      // We can map a cell event through to the view without widening
      // when the following conditions apply:
      //
      // a) all the changes are on one row (e.getFirstRow() == e.getLastRow())
      // and,
      // b) all the changes are in one column (column !=
      // TableModelEvent.ALL_COLUMNS) and,
      // c) we are not sorting on that column (getSortingStatus(column) ==
      // NOT_SORTED) and,
      // d) a reverse lookup will not trigger a sort (modelToView != null)
      //
      // Note: INSERT and DELETE events fail this test as they have column ==
      // ALL_COLUMNS.
      //
      // The last check, for (modelToView != null) is to see if modelToView
      // is already allocated. If we don't do this check; sorting can become
      // a performance bottleneck for applications where cells
      // change rapidly in different parts of the table. If cells
      // change alternately in the sorting column and then outside of
      // it this class can end up re-sorting on alternate cell updates -
      // which can be a performance problem for large tables. The last
      // clause avoids this problem.
      int column = e.getColumn();
      if (e.getFirstRow() == e.getLastRow()
              && column != TableModelEvent.ALL_COLUMNS
              && getSortingStatus(column) == NOT_SORTED
              && modelToView != null)
      {
        int viewIndex = getModelToView()[e.getFirstRow()];
        fireTableChanged(new TableModelEvent(TableSorter.this, viewIndex,
                viewIndex, column, e.getType()));
        return;
      }

      // Something has happened to the data that may have invalidated the row
      // order.
      clearSortingState();
      fireTableDataChanged();
      return;
    }
  }

  private class MouseHandler extends MouseAdapter
  {
    public void mouseClicked(MouseEvent e)
    {
      JTableHeader h = (JTableHeader) e.getSource();
      TableColumnModel columnModel = h.getColumnModel();
      int viewColumn = columnModel.getColumnIndexAtX(e.getX());
      int column = columnModel.getColumn(viewColumn).getModelIndex();
      if (column != -1)
      {
        int status = getSortingStatus(column);
        if (!e.isControlDown())
        {
          cancelSorting();
        }
        // Cycle the sorting states through {NOT_SORTED, ASCENDING, DESCENDING}
        // or
        // {NOT_SORTED, DESCENDING, ASCENDING} depending on whether shift is
        // pressed.
        status = status + (e.isShiftDown() ? -1 : 1);
        status = (status + 4) % 3 - 1; // signed mod, returning {-1, 0, 1}
        setSortingStatus(column, status);
      }
    }
  }

  private static class Arrow implements Icon
  {
    private boolean descending;

    private int size;

    private int priority;

    public Arrow(boolean descending, int size, int priority)
    {
      this.descending = descending;
      this.size = size;
      this.priority = priority;
    }

    public void paintIcon(Component c, Graphics g, int x, int y)
    {
      Color color = c == null ? Color.GRAY : c.getBackground();
      // In a compound sort, make each succesive triangle 20%
      // smaller than the previous one.
      int dx = (int) (size / 2 * Math.pow(0.8, priority));
      int dy = descending ? dx : -dx;
      // Align icon (roughly) with font baseline.
      y = y + 5 * size / 6 + (descending ? -dy : 0);
      int shift = descending ? 1 : -1;
      g.translate(x, y);

      // Right diagonal.
      g.setColor(color.darker());
      g.drawLine(dx / 2, dy, 0, 0);
      g.drawLine(dx / 2, dy + shift, 0, shift);

      // Left diagonal.
      g.setColor(color.brighter());
      g.drawLine(dx / 2, dy, dx, 0);
      g.drawLine(dx / 2, dy + shift, dx, shift);

      // Horizontal line.
      if (descending)
      {
        g.setColor(color.darker().darker());
      }
      else
      {
        g.setColor(color.brighter().brighter());
      }
      g.drawLine(dx, 0, 0, 0);

      g.setColor(color);
      g.translate(-x, -y);
    }

    public int getIconWidth()
    {
      return size;
    }

    public int getIconHeight()
    {
      return size;
    }
  }

  private class SortableHeaderRenderer implements TableCellRenderer
  {
    private TableCellRenderer tableCellRenderer;

    public SortableHeaderRenderer(TableCellRenderer tableCellRenderer)
    {
      this.tableCellRenderer = tableCellRenderer;
    }

    public Component getTableCellRendererComponent(JTable table,
            Object value, boolean isSelected, boolean hasFocus, int row,
            int column)
    {
      Component c = tableCellRenderer.getTableCellRendererComponent(table,
              value, isSelected, hasFocus, row, column);
      if (c instanceof JLabel)
      {
        JLabel l = (JLabel) c;
        l.setHorizontalTextPosition(JLabel.LEFT);
        int modelColumn = table.convertColumnIndexToModel(column);
        l.setIcon(
                getHeaderRendererIcon(modelColumn, l.getFont().getSize()));
      }
      return c;
    }
  }

  private static class Directive
  {
    private int column;

    private int direction;

    public Directive(int column, int direction)
    {
      this.column = column;
      this.direction = direction;
    }
  }
}
