package groupable_header;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Vector;
import javax.swing.JComponent;
import javax.swing.plaf.basic.BasicTableHeaderUI;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;


/**
 * This class paints groupable header cells. These can be a combination of
 * normal header cells and groupable cells.
 */
public class GroupableTableHeaderUI extends BasicTableHeaderUI {
    
    /**
     * Contains a list of ColumnGroups that have already been painted
     * in the current paint request.
     */
    protected Vector paintedGroups = new Vector();
    
    /**
     * Paint a representation of the table header.
     * @param g the Graphics context in which to paint
     * @param c the component being painted; this argument is often ignored
     */
    public void paint(Graphics g, JComponent c) {
        Rectangle clipBounds = g.getClipBounds();
        GroupableTableColumnModel cm = (GroupableTableColumnModel)header.getColumnModel();
        if (cm == null) return;
        ((GroupableTableHeader)header).setColumnMargin();
        int column = 0;
        Dimension size = header.getSize();
        Rectangle cellRect  = new Rectangle(0, 0, size.width, size.height);
        Hashtable h = new Hashtable();
        int columnMargin = cm.getColumnMargin();
        
        Enumeration columns = cm.getColumns();
        while (columns.hasMoreElements()) {
            cellRect.height = size.height;
            cellRect.y      = 0;
            TableColumn aColumn = (TableColumn)columns.nextElement();
            Iterator colGrpIter = cm.getColumnGroups(aColumn);
            if (colGrpIter != null) {
                int groupHeight = 0;
                while (colGrpIter.hasNext()) {
                    ColumnGroup cGroup = (ColumnGroup)colGrpIter.next();
                    Rectangle groupRect = (Rectangle)h.get(cGroup);
                    if (groupRect == null) {
                        groupRect = new Rectangle(cellRect);
                        Dimension d = cGroup.getSize(header.getTable());
                        groupRect.width  = d.width;
                        groupRect.height = d.height;
                        h.put(cGroup, groupRect);
                    }
                    if(!paintedGroups.contains(cGroup)) {
                        paintCell(g, groupRect, cGroup);
                        paintedGroups.add(cGroup);
                    }
                    groupHeight += groupRect.height;
                    cellRect.height = size.height - groupHeight;
                    cellRect.y      = groupHeight;
                }
            }
            cellRect.width = aColumn.getWidth();
            if (cellRect.intersects(clipBounds)) {
                paintCell(g, cellRect, column);
            }
            cellRect.x += cellRect.width;
            column++;
        }
        paintedGroups.clear();
    }
    
    /**
     * Paints a header column cell.
     * @param g Graphics context
     * @param cellRect The rectangle to contain the cell
     * @param columnIndex The header column to be painted
     */    
    private void paintCell(Graphics g, Rectangle cellRect, int columnIndex) {
        TableColumn aColumn = header.getColumnModel().getColumn(columnIndex);
        TableCellRenderer renderer = aColumn.getHeaderRenderer();
        if(renderer == null) {
            renderer = header.getDefaultRenderer();
        }
        Component component = renderer.getTableCellRendererComponent(
        header.getTable(), aColumn.getHeaderValue(),false, false, -1, columnIndex);
        rendererPane.add(component);
        rendererPane.paintComponent(g, component, header, cellRect.x, cellRect.y,
        cellRect.width, cellRect.height, true);
    }
    
    /**
     * Paint group column cell.
     * @param g Graphics context
     * @param cellRect Rectangle that the cell with be painted in
     * @param cGroup Current column group
     */    
    private void paintCell(Graphics g, Rectangle cellRect,ColumnGroup cGroup) {
        TableCellRenderer renderer = cGroup.getHeaderRenderer();
        Component component = renderer.getTableCellRendererComponent(
        header.getTable(), cGroup.getHeaderValue(),false, false, -1, -1);
        rendererPane.add(component);
        rendererPane.paintComponent(g, component, header, cellRect.x, cellRect.y,
        cellRect.width, cellRect.height, true);
    }
    
    /**
     * Calculate and return the height of the header.
     * @return Header Height
     */    
    private int getHeaderHeight() {
        int height = 0;
        GroupableTableColumnModel columnModel = (GroupableTableColumnModel)header.getColumnModel();
        for(int column = 0; column < columnModel.getColumnCount(); column++) {
            TableColumn aColumn = columnModel.getColumn(column);
            TableCellRenderer renderer = aColumn.getHeaderRenderer();
            if(renderer == null) {
                renderer = header.getDefaultRenderer();
            }
            Component comp = renderer.getTableCellRendererComponent(
            header.getTable(), aColumn.getHeaderValue(), false, false,-1, column);
            int cHeight = comp.getPreferredSize().height;
            Iterator iter = columnModel.getColumnGroups(aColumn);
            if (iter != null) {
                while (iter.hasNext()) {
                    ColumnGroup cGroup = (ColumnGroup)iter.next();
                    cHeight += cGroup.getSize(header.getTable()).height;
                }
            }
            height = Math.max(height, cHeight);
        }
        return height;
    }
    
    /**
     * Calculate and return the dimension of the header.
     * @param width Starting width to be used.
     * @return Dimension of the header
     */    
    private Dimension createHeaderSize(long width) {
        TableColumnModel columnModel = header.getColumnModel();
        width += columnModel.getColumnMargin() * columnModel.getColumnCount();
        if (width > Integer.MAX_VALUE) {
            width = Integer.MAX_VALUE;
        }
        return new Dimension((int)width, getHeaderHeight());
    }
    
    /**
     * Invokes the getPreferredSize method on each UI handled by this object.
     * @param c the component whose preferred size is being queried; this argument is ignored.
     * @return the dimension of the whole header
     */
    public Dimension getPreferredSize(JComponent c) {
        long width = 0;
        Enumeration columns = header.getColumnModel().getColumns();
        while (columns.hasMoreElements()) {
            TableColumn aColumn = (TableColumn)columns.nextElement();
            width = width + aColumn.getPreferredWidth();
        }
        return createHeaderSize(width);
    }
}