/*******************************************************************************
 * Copyright (c) 2008 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.jface.viewers.DelegatingStyledCellLabelProvider;

import dwtx.jface.viewers.StyledCellLabelProvider;
import dwtx.jface.viewers.IBaseLabelProvider;
import dwtx.jface.viewers.StyledString;
import dwtx.jface.viewers.ViewerCell;
import dwtx.jface.viewers.ILabelProviderListener;
import dwtx.jface.viewers.IColorProvider;
import dwtx.jface.viewers.IFontProvider;

import dwt.custom.StyleRange;
import dwt.graphics.Color;
import dwt.graphics.Font;
import dwt.graphics.Image;

import dwt.dwthelper.utils;
import dwtx.dwtxhelper.Collection;

/**
 * A {@link DelegatingStyledCellLabelProvider} is a
 * {@link StyledCellLabelProvider} that delegates requests for the styled string
 * and the image to a
 * {@link DelegatingStyledCellLabelProvider.IStyledLabelProvider}.
 *
 * <p>
 * Existing label providers can be enhanced by implementing
 * {@link DelegatingStyledCellLabelProvider.IStyledLabelProvider} so they can be
 * used in viewers with styled labels.
 * </p>
 *
 * <p>
 * The {@link DelegatingStyledCellLabelProvider.IStyledLabelProvider} can
 * optionally implement {@link IColorProvider} and {@link IFontProvider} to
 * provide foreground and background color and a default font.
 * </p>
 *
 * @since 3.4
 */
public class DelegatingStyledCellLabelProvider : StyledCellLabelProvider {

    /**
     * Interface marking a label provider that provides styled text labels and
     * images.
     * <p>
     * The {@link DelegatingStyledCellLabelProvider.IStyledLabelProvider} can
     * optionally implement {@link IColorProvider} and {@link IFontProvider} to
     * provide foreground and background color and a default font.
     * </p>
     */
    public static interface IStyledLabelProvider : IBaseLabelProvider {

        /**
         * Returns the styled text label for the given element
         *
         * @param element
         *            the element to evaluate the styled string for
         *
         * @return the styled string.
         */
        public StyledString getStyledText(Object element);

        /**
         * Returns the image for the label of the given element. The image is
         * owned by the label provider and must not be disposed directly.
         * Instead, dispose the label provider when no longer needed.
         *
         * @param element
         *            the element for which to provide the label image
         * @return the image used to label the element, or <code>null</code>
         *         if there is no image for the given object
         */
        public Image getImage(Object element);
    }

    private IStyledLabelProvider styledLabelProvider;

    /**
     * Creates a {@link DelegatingStyledCellLabelProvider} that delegates the
     * requests for the styled labels and the images to a
     * {@link IStyledLabelProvider}.
     *
     * @param labelProvider
     *            the label provider that provides the styled labels and the
     *            images
     */
    public this(IStyledLabelProvider labelProvider) {
        if (labelProvider is null)
            throw new IllegalArgumentException(
                    "Label provider must not be null"); //$NON-NLS-1$

        this.styledLabelProvider = labelProvider;
    }

    /*
     * (non-Javadoc)
     *
     * @see dwtx.jface.viewers.StyledCellLabelProvider#update(dwtx.jface.viewers.ViewerCell)
     */
    public void update(ViewerCell cell) {
        Object element = cell.getElement();

        StyledString styledString = getStyledText(element);
        String newText= styledString.toString();

        StyleRange[] oldStyleRanges= cell.getStyleRanges();
        StyleRange[] newStyleRanges= isOwnerDrawEnabled() ? styledString.getStyleRanges() : null;

        if (!Arrays.equals(oldStyleRanges, newStyleRanges)) {
            cell.setStyleRanges(newStyleRanges);
            if (cell.getText().equals(newText)) {
                // make sure there will be a refresh from a change
                cell.setText(""); //$NON-NLS-1$
            }
        }

        cell.setText(newText);
        cell.setImage(getImage(element));
        cell.setFont(getFont(element));
        cell.setForeground(getForeground(element));
        cell.setBackground(getBackground(element));

        // no super call required. changes on item will trigger the refresh.
    }

    /**
     * Provides a foreground color for the given element.
     *
     * @param element
     *            the element
     * @return the foreground color for the element, or <code>null</code> to
     *         use the default foreground color
     */
    public Color getForeground(Object element) {
        if (null !is cast(IColorProvider)this.styledLabelProvider ) {
            return (cast(IColorProvider) this.styledLabelProvider)
                    .getForeground(element);
        }
        return null;
    }

    /**
     * Provides a background color for the given element.
     *
     * @param element
     *            the element
     * @return the background color for the element, or <code>null</code> to
     *         use the default background color
     */
    public Color getBackground(Object element) {
        if (null !is cast(IColorProvider)this.styledLabelProvider) {
            return (cast(IColorProvider) this.styledLabelProvider)
                    .getBackground(element);
        }
        return null;
    }

    /**
     * Provides a font for the given element.
     *
     * @param element
     *            the element
     * @return the font for the element, or <code>null</code> to use the
     *         default font
     */
    public Font getFont(Object element) {
        if (null !is cast(IFontProvider)this.styledLabelProvider ) {
            return (cast(IFontProvider) this.styledLabelProvider).getFont(element);
        }
        return null;
    }

    /**
     * Returns the image for the label of the given element. The image is owned
     * by the label provider and must not be disposed directly. Instead, dispose
     * the label provider when no longer needed.
     *
     * @param element
     *            the element for which to provide the label image
     * @return the image used to label the element, or <code>null</code> if
     *         there is no image for the given object
     */
    public Image getImage(Object element) {
        return this.styledLabelProvider.getImage(element);
    }

    /**
     * Returns the styled text for the label of the given element.
     *
     * @param element
     *            the element for which to provide the styled label text
     * @return the styled text string used to label the element
     */
    protected StyledString getStyledText(Object element) {
        return this.styledLabelProvider.getStyledText(element);
    }

    /**
     * Returns the styled string provider.
     *
     * @return the wrapped label provider
     */
    public IStyledLabelProvider getStyledStringProvider() {
        return this.styledLabelProvider;
    }

    public void addListener(ILabelProviderListener listener) {
        super.addListener(listener);
        this.styledLabelProvider.addListener(listener);
    }

    public void removeListener(ILabelProviderListener listener) {
        super.removeListener(listener);
        this.styledLabelProvider.removeListener(listener);
    }

    public bool isLabelProperty(Object element, String property) {
        return this.styledLabelProvider.isLabelProperty(element, property);
    }

    public void dispose() {
        super.dispose();
        this.styledLabelProvider.dispose();
    }

}