/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpeclipse.phpeditor;

import net.sourceforge.phpdt.internal.ui.PHPUiImages;
import net.sourceforge.phpdt.ui.PreferenceConstants;
import net.sourceforge.phpdt.ui.actions.PHPEditorActionDefinitionIds;
import net.sourceforge.phpeclipse.PHPeclipsePlugin;

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 toolbar 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(PHPEditorMessages.getResourceBundle(),
				"TogglePresentation.", null); //$NON-NLS-1$
		PHPUiImages.setToolImageDescriptors(this, "segment_edit.gif"); //$NON-NLS-1$
		setToolTipText(PHPEditorMessages
				.getString("TogglePresentation.tooltip")); //$NON-NLS-1$
		setActionDefinitionId(PHPEditorActionDefinitionIds.TOGGLE_PRESENTATION);
		// WorkbenchHelp.setHelp(this,
		// IJavaHelpContextIds.TOGGLE_PRESENTATION_ACTION);
		update();
	}

	/*
	 * @see IAction#actionPerformed
	 */
	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(PreferenceConstants.EDITOR_SHOW_SEGMENTS, showAll);
		fStore.addPropertyChangeListener(this);
	}

	/*
	 * @see TextEditorAction#update
	 */
	public void update() {
		ITextEditor editor = getTextEditor();
		boolean checked = (editor != null && editor.showsHighlightRangeOnly());
		setChecked(checked);
		setEnabled(editor != null);
	}

	/*
	 * @see TextEditorAction#setEditor(ITextEditor)
	 */
	public void setEditor(ITextEditor editor) {

		super.setEditor(editor);

		if (editor != null) {

			if (fStore == null) {
				fStore = PHPeclipsePlugin.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
	 * tells him.
	 */
	private void synchronizeWithPreference(ITextEditor editor) {

		if (editor == null)
			return;

		boolean showSegments = fStore
				.getBoolean(PreferenceConstants.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);
		}
	}

	/*
	 * @see IPropertyChangeListener#propertyChange(PropertyChangeEvent)
	 */
	public void propertyChange(PropertyChangeEvent event) {
		if (event.getProperty()
				.equals(PreferenceConstants.EDITOR_SHOW_SEGMENTS))
			synchronizeWithPreference(getTextEditor());
	}
}
