/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.viewers;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.TableTree;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.PaletteData;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.ColorDialog;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.Tree;

/**
 * A cell editor that manages a color field.
 * The cell editor's value is the color (an SWT <code>RBG</code>).
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 */
public class ColorCellEditor extends DialogCellEditor {

    /**
     * The default extent in pixels.
     */
    private static final int DEFAULT_EXTENT = 16;

    /**
     * Gap between between image and text in pixels.
     */
    private static final int GAP = 6;

    /**
     * The composite widget containing the color and RGB label widgets
     */
    private Composite composite;

    /**
     * The label widget showing the current color.
     */
    private Label colorLabel;

    /**
     * The label widget showing the RGB values.
     */
    private Label rgbLabel;

    /**
     * The image.
     */
    private Image image;

    /**
     * Internal class for laying out this cell editor.
     */
    private class ColorCellLayout extends Layout {
        public Point computeSize(Composite editor, int wHint, int hHint,
                boolean force) {
            if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)
                return new Point(wHint, hHint);
            Point colorSize = colorLabel.computeSize(SWT.DEFAULT, SWT.DEFAULT,
                    force);
            Point rgbSize = rgbLabel.computeSize(SWT.DEFAULT, SWT.DEFAULT,
                    force);
            return new Point(colorSize.x + GAP + rgbSize.x, Math.max(
                    colorSize.y, rgbSize.y));
        }

        public void layout(Composite editor, boolean force) {
            Rectangle bounds = editor.getClientArea();
            Point colorSize = colorLabel.computeSize(SWT.DEFAULT, SWT.DEFAULT,
                    force);
            Point rgbSize = rgbLabel.computeSize(SWT.DEFAULT, SWT.DEFAULT,
                    force);
            int ty = (bounds.height - rgbSize.y) / 2;
            if (ty < 0)
                ty = 0;
            colorLabel.setBounds(-1, 0, colorSize.x, colorSize.y);
            rgbLabel.setBounds(colorSize.x + GAP - 1, ty, bounds.width
                    - colorSize.x - GAP, bounds.height);
        }
    }

    /**
     * Creates a new color cell editor parented under the given control.
     * The cell editor value is black (<code>RGB(0,0,0)</code>) initially, and has no 
     * validator.
     *
     * @param parent the parent control
     */
    public ColorCellEditor(Composite parent) {
        this(parent, SWT.NONE);
    }

    /**
     * Creates a new color cell editor parented under the given control.
     * The cell editor value is black (<code>RGB(0,0,0)</code>) initially, and has no 
     * validator.
     *
     * @param parent the parent control
     * @param style the style bits
     * @since 2.1
     */
    public ColorCellEditor(Composite parent, int style) {
        super(parent, style);
        doSetValue(new RGB(0, 0, 0));
    }

    /**
     * Creates and returns the color image data for the given control
     * and RGB value. The image's size is either the control's item extent 
     * or the cell editor's default extent, which is 16 pixels square.
     *
     * @param w the control
     * @param color the color
     */
    private ImageData createColorImage(Control w, RGB color) {

        GC gc = new GC(w);
        FontMetrics fm = gc.getFontMetrics();
        int size = fm.getAscent();
        gc.dispose();

        int indent = 6;
        int extent = DEFAULT_EXTENT;
        if (w instanceof Table)
            extent = ((Table) w).getItemHeight() - 1;
        else if (w instanceof Tree)
            extent = ((Tree) w).getItemHeight() - 1;
        else if (w instanceof TableTree)
            extent = ((TableTree) w).getItemHeight() - 1;

        if (size > extent)
            size = extent;

        int width = indent + size;
        int height = extent;

        int xoffset = indent;
        int yoffset = (height - size) / 2;

        RGB black = new RGB(0, 0, 0);
        PaletteData dataPalette = new PaletteData(new RGB[] { black, black,
                color });
        ImageData data = new ImageData(width, height, 4, dataPalette);
        data.transparentPixel = 0;

        int end = size - 1;
        for (int y = 0; y < size; y++) {
            for (int x = 0; x < size; x++) {
                if (x == 0 || y == 0 || x == end || y == end)
                    data.setPixel(x + xoffset, y + yoffset, 1);
                else
                    data.setPixel(x + xoffset, y + yoffset, 2);
            }
        }

        return data;
    }

    /* (non-Javadoc)
     * Method declared on DialogCellEditor.
     */
    protected Control createContents(Composite cell) {
        Color bg = cell.getBackground();
        composite = new Composite(cell, getStyle());
        composite.setBackground(bg);
        composite.setLayout(new ColorCellLayout());
        colorLabel = new Label(composite, SWT.LEFT);
        colorLabel.setBackground(bg);
        rgbLabel = new Label(composite, SWT.LEFT);
        rgbLabel.setBackground(bg);
        rgbLabel.setFont(cell.getFont());
        return composite;
    }

    /* (non-Javadoc)
     * Method declared on CellEditor.
     */
    public void dispose() {
        if (image != null) {
            image.dispose();
            image = null;
        }
        super.dispose();
    }

    /* (non-Javadoc)
     * Method declared on DialogCellEditor.
     */
    protected Object openDialogBox(Control cellEditorWindow) {
        ColorDialog dialog = new ColorDialog(cellEditorWindow.getShell());
        Object value = getValue();
        if (value != null)
            dialog.setRGB((RGB) value);
        value = dialog.open();
        return dialog.getRGB();
    }

    /* (non-Javadoc)
     * Method declared on DialogCellEditor.
     */
    protected void updateContents(Object value) {
        RGB rgb = (RGB) value;
        // XXX: We don't have a value the first time this method is called".
        if (rgb == null) {
            rgb = new RGB(0, 0, 0);
        }
        // XXX: Workaround for 1FMQ0P3: SWT:ALL - TableItem.setImage doesn't work if using the identical image."
        if (image != null)
            image.dispose();

        ImageData id = createColorImage(colorLabel.getParent().getParent(), rgb);
        ImageData mask = id.getTransparencyMask();
        image = new Image(colorLabel.getDisplay(), id, mask);
        colorLabel.setImage(image);

        rgbLabel
                .setText("(" + rgb.red + "," + rgb.green + "," + rgb.blue + ")");//$NON-NLS-4$//$NON-NLS-3$//$NON-NLS-2$//$NON-NLS-1$
    }
}