/*******************************************************************************
 * Copyright (c) 2006 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.wst.sse.ui;

import java.util.ResourceBundle;

import org.eclipse.jface.action.IAction;
import org.eclipse.jface.action.IMenuManager;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.ITextOperationTarget;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.source.projection.IProjectionListener;
import org.eclipse.jface.text.source.projection.ProjectionViewer;
import org.eclipse.ui.actions.ActionGroup;
import org.eclipse.ui.editors.text.IFoldingCommandIds;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.ui.texteditor.IUpdate;
import org.eclipse.ui.texteditor.ResourceAction;
import org.eclipse.ui.texteditor.TextOperationAction;
import org.eclipse.wst.sse.ui.internal.SSEUIMessages;
import org.eclipse.wst.sse.ui.internal.SSEUIPlugin;
import org.eclipse.wst.sse.ui.internal.projection.IStructuredTextFoldingProvider;

class FoldingActionGroup extends ActionGroup {
	private static abstract class PreferenceAction extends ResourceAction implements IUpdate {
		PreferenceAction(ResourceBundle bundle, String prefix, int style) {
			super(bundle, prefix, style);
		}
	}

	private ProjectionViewer fViewer;

	private final PreferenceAction fToggle;
	private final TextOperationAction fExpandAll;
	private final IProjectionListener fProjectionListener;
	private final TextOperationAction fCollapseAll;


	/**
	 * Creates a new projection action group for <code>editor</code>. If
	 * the supplied viewer is not an instance of <code>ProjectionViewer</code>,
	 * the action group is disabled.
	 * 
	 * @param editor
	 *            the text editor to operate on
	 * @param viewer
	 *            the viewer of the editor
	 */
	public FoldingActionGroup(final ITextEditor editor, ITextViewer viewer) {
		if (!(viewer instanceof ProjectionViewer)) {
			fToggle = null;
			fExpandAll = null;
			fCollapseAll = null;
			fProjectionListener = null;
			return;
		}

		fViewer = (ProjectionViewer) viewer;

		fProjectionListener = new IProjectionListener() {

			public void projectionEnabled() {
				update();
			}

			public void projectionDisabled() {
				update();
			}
		};

		fViewer.addProjectionListener(fProjectionListener);

		fToggle = new PreferenceAction(SSEUIMessages.getResourceBundle(), "Projection_Toggle_", IAction.AS_CHECK_BOX) { //$NON-NLS-1$
			public void run() {
				IPreferenceStore store = SSEUIPlugin.getDefault().getPreferenceStore();
				boolean current = store.getBoolean(IStructuredTextFoldingProvider.FOLDING_ENABLED);
				store.setValue(IStructuredTextFoldingProvider.FOLDING_ENABLED, !current);
			}

			public void update() {
				ITextOperationTarget target = (ITextOperationTarget) editor.getAdapter(ITextOperationTarget.class);

				boolean isEnabled = (target != null && target.canDoOperation(ProjectionViewer.TOGGLE));
				setEnabled(isEnabled);
			}
		};
		fToggle.setChecked(true);
		fToggle.setActionDefinitionId(IFoldingCommandIds.FOLDING_TOGGLE);
		editor.setAction("FoldingToggle", fToggle); //$NON-NLS-1$

		fExpandAll = new TextOperationAction(SSEUIMessages.getResourceBundle(), "Projection_ExpandAll_", editor, ProjectionViewer.EXPAND_ALL, true); //$NON-NLS-1$
		fExpandAll.setActionDefinitionId(IFoldingCommandIds.FOLDING_EXPAND_ALL);
		editor.setAction("FoldingExpandAll", fExpandAll); //$NON-NLS-1$

		fCollapseAll = new TextOperationAction(SSEUIMessages.getResourceBundle(), "Projection_CollapseAll_", editor, ProjectionViewer.COLLAPSE_ALL, true); //$NON-NLS-1$
		fCollapseAll.setActionDefinitionId(IFoldingCommandIds.FOLDING_COLLAPSE_ALL);
		editor.setAction("FoldingCollapseAll", fCollapseAll); //$NON-NLS-1$
	}

	/**
	 * Returns <code>true</code> if the group is enabled.
	 * 
	 * <pre>
	 *        Invariant: isEnabled() &lt;=&gt; fViewer and all actions are != null.
	 * </pre>
	 * 
	 * @return <code>true</code> if the group is enabled
	 */
	protected boolean isEnabled() {
		return fViewer != null;
	}

	/*
	 * @see org.eclipse.ui.actions.ActionGroup#dispose()
	 */
	public void dispose() {
		if (isEnabled()) {
			fViewer.removeProjectionListener(fProjectionListener);
			fViewer = null;
		}
		super.dispose();
	}

	/**
	 * Updates the actions.
	 */
	protected void update() {
		if (isEnabled()) {
			fToggle.update();
			fToggle.setChecked(fViewer.isProjectionMode());
			fExpandAll.update();
			fCollapseAll.update();
		}
	}

	/**
	 * Fills the menu with all folding actions.
	 * 
	 * @param manager
	 *            the menu manager for the folding submenu
	 */
	public void fillMenu(IMenuManager manager) {
		if (isEnabled()) {
			update();
			manager.add(fToggle);
			manager.add(fExpandAll);
			manager.add(fCollapseAll);
		}
	}

	/*
	 * @see org.eclipse.ui.actions.ActionGroup#updateActionBars()
	 */
	public void updateActionBars() {
		update();
	}
}