/*=============================================================================#
 # Copyright (c) 2011, 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ecommons.text.ui;

import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_SELECTION_BACKGROUND;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_SELECTION_BACKGROUND_SYSTEM_DEFAULT;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_SELECTION_FOREGROUND;
import static org.eclipse.ui.texteditor.AbstractTextEditor.PREFERENCE_COLOR_SELECTION_FOREGROUND_SYSTEM_DEFAULT;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.text.source.SourceViewer;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.RGB;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;

import org.eclipse.statet.ecommons.ui.util.UIAccess;


@NonNullByDefault
public class TextViewerEditorColorUpdater {
	
	
	protected final ISourceViewer viewer;
	protected final IPreferenceStore preferenceStore;
	
	private @Nullable IPropertyChangeListener listener;
	
	
	public TextViewerEditorColorUpdater(final SourceViewer viewer, final IPreferenceStore preferenceStore) {
		assert (viewer != null);
		assert (preferenceStore != null);
		
		this.viewer= viewer;
		this.preferenceStore= preferenceStore;
		
		viewer.getTextWidget().addDisposeListener(new DisposeListener() {
			@Override
			public void widgetDisposed(final DisposeEvent e) {
				dispose();
			}
		});
		
		this.listener= new IPropertyChangeListener() {
			@Override
			public void propertyChange(final PropertyChangeEvent event) {
				if (PREFERENCE_COLOR_FOREGROUND.equals(event.getProperty())
						|| PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT.equals(event.getProperty())
						|| PREFERENCE_COLOR_BACKGROUND.equals(event.getProperty())
						|| PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT.equals(event.getProperty())
						|| PREFERENCE_COLOR_SELECTION_FOREGROUND.equals(event.getProperty())
						|| PREFERENCE_COLOR_SELECTION_FOREGROUND_SYSTEM_DEFAULT.equals(event.getProperty())
						|| PREFERENCE_COLOR_SELECTION_BACKGROUND.equals(event.getProperty())
						|| PREFERENCE_COLOR_SELECTION_BACKGROUND_SYSTEM_DEFAULT.equals(event.getProperty()) ) {
					updateColors();
				}
			}
		};
		this.preferenceStore.addPropertyChangeListener(this.listener);
		
		updateColors();
	}
	
	
	protected void updateColors() {
		final var viewer= this.viewer;
		final StyledText styledText= viewer.getTextWidget();
		if (styledText != null && !styledText.isDisposed()) {
			update(viewer, styledText);
		}
	}
	
	protected void update(final ISourceViewer viewer, final StyledText styledText) {
		{	// foreground color
			final Color color= this.preferenceStore.getBoolean(
					PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT) ? null :
							createColor(this.preferenceStore, PREFERENCE_COLOR_FOREGROUND);
			styledText.setForeground(color);
		}
		{	// background color
			final Color color= this.preferenceStore.getBoolean(
					PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT) ? null :
							createColor(this.preferenceStore, PREFERENCE_COLOR_BACKGROUND);
			styledText.setBackground(color);
		}
		{	// selection foreground color
			final Color color= this.preferenceStore.getBoolean(
					PREFERENCE_COLOR_SELECTION_FOREGROUND_SYSTEM_DEFAULT) ? null :
							createColor(this.preferenceStore, PREFERENCE_COLOR_SELECTION_FOREGROUND);
			styledText.setSelectionForeground(color);
		}
		{	// selection background color
			final Color color= this.preferenceStore.getBoolean(
					PREFERENCE_COLOR_SELECTION_BACKGROUND_SYSTEM_DEFAULT) ? null :
							createColor(this.preferenceStore, PREFERENCE_COLOR_SELECTION_BACKGROUND);
			styledText.setSelectionBackground(color);
		}
	}
	
	protected @Nullable Color createColor(final IPreferenceStore store, final String key) {
		final RGB rgb= PreferenceConverter.getColor(store, key);
		return (rgb != null) ? new Color(rgb) : null;
	}
	
	
	protected void dispose() {
		{	final var listener= this.listener;
			if (listener != null) {
				this.listener= null;
				this.preferenceStore.removePropertyChangeListener(listener);
			}
		}
		
		final StyledText styledText= this.viewer.getTextWidget();
		if (UIAccess.isOkToUse(styledText)) {
			styledText.setForeground(null);
			styledText.setBackground(null);
			styledText.setSelectionForeground(null);
			styledText.setSelectionBackground(null);
		}
	}
	
}