/*******************************************************************************
 * Copyright (c) 2000, 2005 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.ant.internal.ui.editor.actions;

import org.eclipse.ant.internal.ui.AntUIImages;
import org.eclipse.ant.internal.ui.AntUIPlugin;
import org.eclipse.ant.internal.ui.IAntUIConstants;
import org.eclipse.ant.internal.ui.preferences.AntEditorPreferenceConstants;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.ui.texteditor.TextEditorAction;

/**
 * A tool bar action which toggles the presentation model of the connected text editor. The editor shows either the highlight range only or always the
 * whole document.
 */
public class TogglePresentationAction extends TextEditorAction implements IPropertyChangeListener {

	private IPreferenceStore fStore;

	/**
	 * Constructs and updates the action.
	 */
	public TogglePresentationAction() {
		super(AntEditorActionMessages.getResourceBundle(), "TogglePresentation.", null, IAction.AS_CHECK_BOX); //$NON-NLS-1$
		setImageDescriptor(AntUIImages.getImageDescriptor(IAntUIConstants.IMG_SEGMENT_EDIT));
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.action.IAction#run()
	 */
	@Override
	public void run() {

		ITextEditor editor = getTextEditor();
		if (editor == null) {
			return;
		}

		IRegion remembered = editor.getHighlightRange();
		editor.resetHighlightRange();

		boolean showAll = !editor.showsHighlightRangeOnly();
		setChecked(showAll);

		editor.showHighlightRangeOnly(showAll);
		if (remembered != null) {
			editor.setHighlightRange(remembered.getOffset(), remembered.getLength(), true);
		}

		fStore.removePropertyChangeListener(this);
		fStore.setValue(AntEditorPreferenceConstants.EDITOR_SHOW_SEGMENTS, showAll);
		fStore.addPropertyChangeListener(this);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.texteditor.IUpdate#update()
	 */
	@Override
	public void update() {
		ITextEditor editor = getTextEditor();
		boolean checked = (editor != null && editor.showsHighlightRangeOnly());
		setChecked(checked);
		setEnabled(editor != null);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.texteditor.TextEditorAction#setEditor(org.eclipse.ui.texteditor.ITextEditor)
	 */
	@Override
	public void setEditor(ITextEditor editor) {

		super.setEditor(editor);

		if (editor != null) {

			if (fStore == null) {
				fStore = AntUIPlugin.getDefault().getPreferenceStore();
				fStore.addPropertyChangeListener(this);
			}
			synchronizeWithPreference(editor);

		} else if (fStore != null) {
			fStore.removePropertyChangeListener(this);
			fStore = null;
		}

		update();
	}

	/**
	 * Synchronizes the appearance of the editor with what the preference store indicates
	 * 
	 * @param editor
	 *            the text editor
	 */
	private void synchronizeWithPreference(ITextEditor editor) {

		if (editor == null) {
			return;
		}

		boolean showSegments = fStore.getBoolean(AntEditorPreferenceConstants.EDITOR_SHOW_SEGMENTS);
		setChecked(showSegments);

		if (editor.showsHighlightRangeOnly() != showSegments) {
			IRegion remembered = editor.getHighlightRange();
			editor.resetHighlightRange();
			editor.showHighlightRangeOnly(showSegments);
			if (remembered != null) {
				editor.setHighlightRange(remembered.getOffset(), remembered.getLength(), true);
			}
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
	 */
	@Override
	public void propertyChange(PropertyChangeEvent event) {
		if (event.getProperty().equals(AntEditorPreferenceConstants.EDITOR_SHOW_SEGMENTS)) {
			synchronizeWithPreference(getTextEditor());
		}
	}
}