package org.simantics.spreadsheet.ui;

import java.awt.Color;
import java.awt.Component;
import java.awt.Rectangle;
import java.io.Serializable;

import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.SwingConstants;
import javax.swing.border.Border;
import javax.swing.table.TableCellRenderer;

public class ColumnHeaderRenderer extends JLabel implements TableCellRenderer, Serializable {

	private static final long serialVersionUID = 1L;


	/**
	 * An empty <code>Border</code>. This field might not be used. To change the
	 * <code>Border</code> used by this renderer override the 
	 * <code>getTableCellRendererComponent</code> method and set the border
	 * of the returned component directly.
	 */

	// We need a place to store the color the JLabel should be returned 
	// to after its foreground and background colors have been set 
	// to the selection background color. 
	// These ivars will be made protected when their names are finalized. 
	private Color unselectedForeground; 
	private Color unselectedBackground; 

	/**
	 * Creates a default table cell renderer.
	 */
	public ColumnHeaderRenderer() {
		super();
		setOpaque(true);
		setHorizontalAlignment(SwingConstants.CENTER);
		setBackground(DefaultLookup.GRAY);
		setBorder(getNoFocusBorder());
		setName("Table.cellRenderer");
	}

	private Border getNoFocusBorder() {
		return TableBorder.BORDER;
	}

	/**
	 * Overrides <code>JComponent.setForeground</code> to assign
	 * the unselected-foreground color to the specified color.
	 * 
	 * @param c set the foreground color to this value
	 */
	public void setForeground(Color c) {
		super.setForeground(c); 
		unselectedForeground = c; 
	}

	/**
	 * Overrides <code>JComponent.setBackground</code> to assign
	 * the unselected-background color to the specified color.
	 *
	 * @param c set the background color to this value
	 */
	public void setBackground(Color c) {
		super.setBackground(c); 
		unselectedBackground = c; 
	}

	/**
	 * Notification from the <code>UIManager</code> that the look and feel
	 * [L&F] has changed.
	 * Replaces the current UI object with the latest version from the 
	 * <code>UIManager</code>.
	 *
	 * @see JComponent#updateUI
	 */
	public void updateUI() {
		super.updateUI(); 
		setForeground(null);
		setBackground(null);
	}

	// implements javax.swing.table.TableCellRenderer
	/**
	 *
	 * Returns the default table cell renderer.
	 * <p>
	 * During a printing operation, this method will be called with
	 * <code>isSelected</code> and <code>hasFocus</code> values of
	 * <code>false</code> to prevent selection and focus from appearing
	 * in the printed output. To do other customization based on whether
	 * or not the table is being printed, check the return value from
	 * {@link javax.swing.JComponent#isPaintingForPrint()}.
	 *
	 * @param table  the <code>JTable</code>
	 * @param value  the value to assign to the cell at
	 *			<code>[row, column]</code>
	 * @param isSelected true if cell is selected
	 * @param hasFocus true if cell has focus
	 * @param row  the row of the cell to render
	 * @param column the column of the cell to render
	 * @return the default table cell renderer
	 * @see javax.swing.JComponent#isPaintingForPrint()
	 */
	public Component getTableCellRendererComponent(JTable table, Object value,
			boolean isSelected, boolean hasFocus, int row, int column) {

		Color fg = null;
		Color bg = null;

		JTable.DropLocation dropLocation = table.getDropLocation();
		if (dropLocation != null
				&& !dropLocation.isInsertRow()
				&& !dropLocation.isInsertColumn()
				&& dropLocation.getRow() == row
				&& dropLocation.getColumn() == column) {

			fg = DefaultLookup.getColor(this, ui, "Table.dropCellForeground");
			bg = DefaultLookup.getColor(this, ui, "Table.dropCellBackground");

			isSelected = true;
		}

		if (isSelected) {
			super.setForeground(fg == null ? table.getSelectionForeground()
					: fg);
			super.setBackground(bg == null ? table.getSelectionBackground()
					: bg);
		} else {
			Color background = unselectedBackground != null
			? unselectedBackground
					: table.getBackground();
			if (background == null || background instanceof javax.swing.plaf.UIResource) {
				Color alternateColor = DefaultLookup.getColor(this, ui, "Table.alternateRowColor");
				if (alternateColor != null && row % 2 == 0)
					background = alternateColor;
			}
			super.setForeground(unselectedForeground != null
					? unselectedForeground
							: table.getForeground());
			super.setBackground(background);
		}

		setFont(table.getFont());

		if (hasFocus) {
			Border border = null;
			if (isSelected) {
				border = DefaultLookup.getBorder(this, ui, "Table.focusSelectedCellHighlightBorder");
			}
			if (border == null) {
				border = DefaultLookup.getBorder(this, ui, "Table.focusCellHighlightBorder");
			}
			setBorder(border);

			if (!isSelected && table.isCellEditable(row, column)) {
				Color col;
				col = DefaultLookup.getColor(this, ui, "Table.focusCellForeground");
				if (col != null) {
					super.setForeground(col);
				}
				col = DefaultLookup.getColor(this, ui, "Table.focusCellBackground");
				if (col != null) {
					super.setBackground(col);
				}
			}
		} else {
			setBorder(getNoFocusBorder());
		}

		setValue(value); 

		return this;
	}

	/*
	 * The following methods are overridden as a performance measure to 
	 * to prune code-paths are often called in the case of renders
	 * but which we know are unnecessary.  Great care should be taken
	 * when writing your own renderer to weigh the benefits and 
	 * drawbacks of overriding methods like these.
	 */

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	public boolean isOpaque() { 
		Color back = getBackground();
		Component p = getParent(); 
		if (p != null) { 
			p = p.getParent(); 
		}

		// p should now be the JTable. 
		boolean colorMatch = (back != null) && (p != null) && 
		back.equals(p.getBackground()) && 
		p.isOpaque();
		return !colorMatch && super.isOpaque(); 
	}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 *
	 * @since 1.5
	 */
	public void invalidate() {}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	public void validate() {}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	public void revalidate() {}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	public void repaint(long tm, int x, int y, int width, int height) {}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	public void repaint(Rectangle r) { }

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 *
	 * @since 1.5
	 */
	public void repaint() {
	}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {	
		// Strings get interned...
		if (propertyName=="text"
			|| propertyName == "labelFor"
				|| propertyName == "displayedMnemonic"
					|| ((propertyName == "font" || propertyName == "foreground")
							&& oldValue != newValue
							&& getClientProperty(javax.swing.plaf.basic.BasicHTML.propertyKey) != null)) {

			super.firePropertyChange(propertyName, oldValue, newValue);
		}
	}

	/**
	 * Overridden for performance reasons.
	 * See the <a href="#override">Implementation Note</a> 
	 * for more information.
	 */
	public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) { }


	/**
	 * Sets the <code>String</code> object for the cell being rendered to
	 * <code>value</code>.
	 * 
	 * @param value  the string value for this cell; if value is
	 *		<code>null</code> it sets the text value to an empty string
	 * @see JLabel#setText
	 * 
	 */
	protected void setValue(Object value) {
		setText((value == null) ? "" : value.toString());
	}

}