/*******************************************************************************
 * Copyright (c) 2008, 2011 Wind River Systems 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:
 *     Wind River Systems - initial API and implementation
 *     Winnie Lai (Texas Instruments) - Individual Element Number Format (Bug 202556)
 *******************************************************************************/
package org.eclipse.cdt.dsf.debug.ui.viewmodel.actions;

import org.eclipse.cdt.dsf.ui.viewmodel.IVMAdapter;
import org.eclipse.cdt.dsf.ui.viewmodel.IVMContext;
import org.eclipse.cdt.dsf.ui.viewmodel.IVMProvider;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
import org.eclipse.debug.internal.ui.viewers.model.provisional.TreeModelViewer;
import org.eclipse.debug.ui.DebugUITools;
import org.eclipse.debug.ui.IDebugView;
import org.eclipse.debug.ui.contexts.IDebugContextService;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.ui.IPartService;
import org.eclipse.ui.ISelectionService;
import org.eclipse.ui.IViewPart;
import org.eclipse.ui.IViewSite;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.ui.services.IServiceLocator;

/**
 * Static utility methods for use with View Model related 
 * commands and handlers.
 * 
 * @since 1.1
 */
public class VMHandlerUtils {

    /**
     * Retrieves the active VM provider based on the currently active
     * selection and part.  
     * @param serviceLocator Service locator for access to active selection 
     * and part.
     * 
     * @return The active VM provder.
     */
    static public IVMProvider getActiveVMProvider(IServiceLocator serviceLocator) {
        ISelection selection = null;
        
        ISelectionService selectionService = 
            (ISelectionService)serviceLocator.getService(ISelectionService.class);
        if (selectionService != null) {
            selection = selectionService.getSelection();
        }
        
        if (selection != null && !selection.isEmpty()) {
            return getVMProviderForSelection(selection);
        }
        else {
            IWorkbenchPart part = null;        
            IPartService partService = (IPartService)serviceLocator.getService(IPartService.class);
            if (partService != null) {
                part = partService.getActivePart();
            }
            return getVMProviderForPart(part);
        }
    }

    /**
     * Retrieves the active VM provider based on the given execution event.
     * @param event The execution event which is usually given as an argument 
     * to the command handler execution call.
     * 
     * @return The active VM provder.
     */
    static public IVMProvider getActiveVMProvider(ExecutionEvent event) {
        ISelection selection = HandlerUtil.getCurrentSelection(event);
        if (selection != null && !selection.isEmpty()) {
            return getVMProviderForSelection(selection);
        }
        else {
            IWorkbenchPart part = HandlerUtil.getActivePart(event);        
            return getVMProviderForPart(part);
        }
    }

    /**
     * Retrieves the selection from a given service locator's selection service.
     * @param serviceLocator Service locator for access to active selection 
     * and part.
     * 
     * @return The selection if available; return null otherwise.
     * @since 2.2
     */
    static public ISelection getSelection(IServiceLocator serviceLocator) {
        ISelectionService selectionService = 
            (ISelectionService)serviceLocator.getService(ISelectionService.class);
        if (selectionService != null) {
            return selectionService.getSelection();
        }
        return null;
    }

    public static IVMProvider getVMProviderForPart(IWorkbenchPart part) {
        IDebugContextService contextService = 
            DebugUITools.getDebugContextManager().getContextService(part.getSite().getWorkbenchWindow());

        ISelection debugContext = contextService.getActiveContext(getPartId(part));
        if (debugContext == null) {
            debugContext = contextService.getActiveContext();
        }
        
        Object input = null;
        if (debugContext instanceof IStructuredSelection) {
            input = ((IStructuredSelection)debugContext).getFirstElement();
        }
        
        if (part instanceof IDebugView) {
            Viewer viewer = ((IDebugView)part).getViewer();
            if (input instanceof IAdaptable && viewer instanceof TreeModelViewer) {
                IPresentationContext presContext = ((TreeModelViewer)viewer).getPresentationContext();
                IVMAdapter vmAdapter = (IVMAdapter)((IAdaptable)input).getAdapter(IVMAdapter.class);
                if (vmAdapter != null) {
                    return vmAdapter.getVMProvider(presContext);
                }
            }
        }
        return null;
    }
    
    private static String getPartId(IWorkbenchPart part) {
        if (part instanceof IViewPart) {
            IViewSite site = (IViewSite)part.getSite();
            return site.getId() + (site.getSecondaryId() != null ? (":" + site.getSecondaryId()) : "");  //$NON-NLS-1$ //$NON-NLS-2$
        } else {
            return part.getSite().getId();
        }
    }
    
    public static IVMProvider getVMProviderForSelection(ISelection selection) {
        if (selection instanceof IStructuredSelection) {
            Object element = ((IStructuredSelection)selection).getFirstElement();
            if (element instanceof IVMContext) {
                return ((IVMContext)element).getVMNode().getVMProvider();
            }
        }
        return null;
    }

}