/*******************************************************************************
 * 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.debug.internal.ui.views.variables;

import org.eclipse.debug.core.DebugException;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.ILogicalStructureType;
import org.eclipse.debug.core.model.IExpression;
import org.eclipse.debug.core.model.IValue;
import org.eclipse.debug.core.model.IVariable;
import org.eclipse.debug.internal.ui.IDebugHelpContextIds;
import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.ActionContributionItem;
import org.eclipse.jface.action.IMenuCreator;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.ui.PlatformUI;

/**
 * Drop down action that displays available logical structures for a selected
 * variable or expression.
 */
public class AvailableLogicalStructuresAction extends Action implements IMenuCreator {
	
	private VariablesView fView;
	private Menu fMenu;
	private IValue fValue;
	private ILogicalStructureType[] fTypes;

	public AvailableLogicalStructuresAction(VariablesView view) {
		setView(view);
		setToolTipText(VariablesViewMessages.AvailableLogicalStructuresAction_0); 
		setText(VariablesViewMessages.AvailableLogicalStructuresAction_1); 
		PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IDebugHelpContextIds.VARIABLES_SELECT_LOGICAL_STRUCTURE);
		setEnabled(false);
		setMenuCreator(this);
		init();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.action.IAction#run()
	 */
	public void run() {
	}
	
	protected VariablesView getView() {
		return fView;
	}

	protected void setView(VariablesView view) {
		fView = view;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.action.IMenuCreator#dispose()
	 */
	public void dispose() {
		if (fMenu != null) {
			fMenu.dispose();
		}
		fView= null;
		fValue = null;
		fTypes = null;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.action.IMenuCreator#getMenu(org.eclipse.swt.widgets.Control)
	 */
	public Menu getMenu(Control parent) {
		return null;
	}

	protected void addActionToMenu(Menu parent, Action action) {
		ActionContributionItem item= new ActionContributionItem(action);
		item.fill(parent, -1);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.action.IMenuCreator#getMenu(org.eclipse.swt.widgets.Menu)
	 */
	public Menu getMenu(Menu parent) {
		if (fMenu != null) {
			fMenu.dispose();
		}
		
		fMenu= new Menu(parent);
		ILogicalStructureType[] types = getTypes();
        ILogicalStructureType enabledType = DebugPlugin.getDefaultStructureType(types);
		if (types != null && types.length > 0) {
			for (int i = 0; i < types.length; i++) {
                ILogicalStructureType type= types[i];
				Action action = new SelectLogicalStructureAction(getView(), type, getValue(), types);
                action.setChecked(enabledType == type);
                StringBuffer label= new StringBuffer();
                //add the numerical accelerator
                if (i < 9) {
                    label.append('&');
                    label.append(i + 1);
                    label.append(' ');
                }
                label.append(action.getText());
                action.setText(label.toString());
				addActionToMenu(fMenu, action);
			}
		}
		return fMenu;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ISelectionChangedListener#selectionChanged(org.eclipse.jface.viewers.SelectionChangedEvent)
	 */
	public void init() {
		setValue(null);
		setTypes(null);
		if (getView().isShowLogicalStructure()) {
			ISelection s = getView().getViewer().getSelection();
			if (s instanceof IStructuredSelection) {
				IStructuredSelection selection = (IStructuredSelection) s;
				if (selection.size() == 1) {
					Object obj = selection.getFirstElement();
					IValue value = null;
					if (obj instanceof IVariable) {
						IVariable var = (IVariable) obj;
						try {
							value = var.getValue();
						} catch (DebugException e) {
						}
					} else if (obj instanceof IExpression) {
						IExpression expression = (IExpression)obj;
						value = expression.getValue();
					}
					if (value != null) {
						ILogicalStructureType[] types = DebugPlugin.getLogicalStructureTypes(value);
						if (types.length > 0) {
							setTypes(types);
							setValue(value);
							setEnabled(true);
							return;
						}
					}
				}
			}
		}
		setEnabled(false);
	}
	
	protected ILogicalStructureType[] getTypes() {
		return fTypes;
	}
	
	private void setTypes(ILogicalStructureType[] types) {
		fTypes = types;
	}
	
	protected IValue getValue() {
		return fValue;
	}
	
	private void setValue(IValue value) {
		fValue = value;
	}
}