/*******************************************************************************
 * Copyright Technophobia Ltd 2012
 * 
 * This file is part of the Substeps Eclipse Plugin.
 * 
 * The Substeps Eclipse Plugin is free software: you can redistribute it and/or modify
 * it under the terms of the Eclipse Public License v1.0.
 * 
 * The Substeps Eclipse Plugin 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
 * Eclipse Public License for more details.
 * 
 * You should have received a copy of the Eclipse Public License
 * along with the Substeps Eclipse Plugin.  If not, see <http://www.eclipse.org/legal/epl-v10.html>.
 ******************************************************************************/
package com.technophobia.substeps.junit.ui.component;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import org.eclipse.jface.preference.JFacePreferences;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.IWorkbenchPreferenceConstants;
import org.eclipse.ui.PlatformUI;

public class ColoredViewersManager implements IPropertyChangeListener {

    public static final String INHERITED_COLOR_NAME = "org.eclipse.jdt.ui.ColoredLabels.inherited"; //$NON-NLS-1$

    public static final String HIGHLIGHT_BG_COLOR_NAME = "org.eclipse.jdt.ui.ColoredLabels.match_highlight"; //$NON-NLS-1$
    public static final String HIGHLIGHT_WRITE_BG_COLOR_NAME = "org.eclipse.jdt.ui.ColoredLabels.writeaccess_highlight"; //$NON-NLS-1$

    private static ColoredViewersManager fgInstance = new ColoredViewersManager();

    private final Set<ColoringLabelProvider> fManagedLabelProviders;


    public ColoredViewersManager() {
        fManagedLabelProviders = new HashSet<ColoringLabelProvider>();
    }


    public void installColoredLabels(final ColoringLabelProvider labelProvider) {
        if (fManagedLabelProviders.contains(labelProvider))
            return;

        if (fManagedLabelProviders.isEmpty()) {
            // first lp installed
            PlatformUI.getPreferenceStore().addPropertyChangeListener(this);
            JFaceResources.getColorRegistry().addListener(this);
        }
        fManagedLabelProviders.add(labelProvider);
    }


    public void uninstallColoredLabels(final ColoringLabelProvider labelProvider) {
        if (!fManagedLabelProviders.remove(labelProvider))
            return; // not installed

        if (fManagedLabelProviders.isEmpty()) {
            PlatformUI.getPreferenceStore().removePropertyChangeListener(this);
            JFaceResources.getColorRegistry().removeListener(this);
            // last viewer uninstalled
        }
    }


    @Override
    public void propertyChange(final PropertyChangeEvent event) {
        final String property = event.getProperty();
        if (property.equals(JFacePreferences.QUALIFIER_COLOR) || property.equals(JFacePreferences.COUNTER_COLOR)
                || property.equals(JFacePreferences.DECORATIONS_COLOR) || property.equals(HIGHLIGHT_BG_COLOR_NAME)
                || property.equals(HIGHLIGHT_WRITE_BG_COLOR_NAME) || property.equals(INHERITED_COLOR_NAME)
                || property.equals(IWorkbenchPreferenceConstants.USE_COLORED_LABELS)) {
            Display.getDefault().asyncExec(new Runnable() {
                @Override
                public void run() {
                    updateAllViewers();
                }
            });
        }
    }


    protected final void updateAllViewers() {
        for (final Iterator<ColoringLabelProvider> iterator = fManagedLabelProviders.iterator(); iterator.hasNext();) {
            final ColoringLabelProvider lp = iterator.next();
            lp.update();
        }
    }


    public static boolean showColoredLabels() {
        return PlatformUI.getPreferenceStore().getBoolean(IWorkbenchPreferenceConstants.USE_COLORED_LABELS);
    }


    public static void install(final ColoringLabelProvider labelProvider) {
        fgInstance.installColoredLabels(labelProvider);
    }


    public static void uninstall(final ColoringLabelProvider labelProvider) {
        fgInstance.uninstallColoredLabels(labelProvider);
    }

}