/*******************************************************************************
 * 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 org.eclipse.debug.internal.ui.views.expression;


import java.util.List;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.debug.core.DebugEvent;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.IExpressionsListener;
import org.eclipse.debug.core.ILaunch;
import org.eclipse.debug.core.model.IDebugElement;
import org.eclipse.debug.core.model.IDebugTarget;
import org.eclipse.debug.core.model.IExpression;
import org.eclipse.debug.core.model.IVariable;
import org.eclipse.debug.core.model.IWatchExpression;
import org.eclipse.debug.internal.ui.views.variables.VariablesViewEventHandler;
import org.eclipse.debug.ui.AbstractDebugView;
import org.eclipse.debug.ui.DebugUITools;
import org.eclipse.jface.viewers.IContentProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredSelection;
 
/**
 * Updates the expression view
 */ 
public class ExpressionViewEventHandler extends VariablesViewEventHandler implements IExpressionsListener {

	/**
	 * Also update expressions if a target terminates
	 * 
	 * @see org.eclipse.debug.internal.ui.views.variables.VariablesViewEventHandler#doHandleTerminateEvent(org.eclipse.debug.core.DebugEvent)
	 */
	protected void doHandleTerminateEvent(DebugEvent event) {
		super.doHandleTerminateEvent(event);
		if (event.getSource() instanceof IDebugTarget) {
			IExpression[] expressions = DebugPlugin.getDefault().getExpressionManager().getExpressions();
			IAdaptable object = DebugUITools.getDebugContext();
			IDebugElement context= null;
			if (object instanceof IDebugElement) {
				context= (IDebugElement) object;
			} else if (object instanceof ILaunch) {
				context= ((ILaunch) object).getDebugTarget();
			}
			for (int i = 0; i < expressions.length; i++) {
				IExpression expression = expressions[i];
				if (expression instanceof IWatchExpression) {
					((IWatchExpression)expression).setExpressionContext(context);
				}
			}			
		}
	}

	/**
	 * Constructs a new event handler on the given view
	 * 
	 * @param view variables view
	 */
	public ExpressionViewEventHandler(AbstractDebugView view) {
		super(view);
		DebugPlugin plugin= DebugPlugin.getDefault();
		plugin.getExpressionManager().addExpressionListener(this);		
	}
	
	/**
	 * De-registers this event handler from the debug model.
	 */
	public void dispose() {
		DebugPlugin plugin= DebugPlugin.getDefault();
		plugin.getExpressionManager().removeExpressionListener(this);
		super.dispose();
	}	
	
	/**
	 * @see IExpressionsListener#expressionsAdded(IExpression[])
	 */
	public void expressionsAdded(final IExpression[] expressions) {
		Runnable r = new Runnable() {
			public void run() {
				if (isAvailable()) {
					getTreeViewer().getControl().setRedraw(false);
					for (int i = 0; i < expressions.length; i++) {
						IExpression expression = expressions[i];
						insert(expression);	
						getTreeViewer().expandToLevel(expression, 1);
					}
					getTreeViewer().getControl().setFocus();
					selectAndReveal(expressions[expressions.length - 1]);
					getTreeViewer().getControl().setRedraw(true);
				}
			}
		};
		getView().asyncExec(r);
	}

	/**
	 * @see IExpressionsListener#expressionsRemoved(IExpression[])
	 */
	public void expressionsRemoved(final IExpression[] expressions) {
		Runnable r = new Runnable() {
			public void run() {
				if (isAvailable()) {
					getTreeViewer().getControl().setRedraw(false);
					for (int i = 0; i < expressions.length; i++) {
						IExpression expression = expressions[i];
						remove(expression);
						IContentProvider provider= getTreeViewer().getContentProvider();
						if (provider instanceof ExpressionViewContentProvider) {
							ExpressionViewContentProvider expressionProvider= (ExpressionViewContentProvider) provider;
							List decendants = expressionProvider.getCachedDecendants(expression);
							decendants.add(expression);
							// Remove the parent cache for the expression and its children
							expressionProvider.removeCache(decendants.toArray());
							IExpression[] allExpressions= DebugPlugin.getDefault().getExpressionManager().getExpressions();
							if (allExpressions.length > 0) {
								getTreeViewer().setSelection(new StructuredSelection(allExpressions[0]), true);
							}
						}						
					}
					getTreeViewer().getControl().setRedraw(true);
				}
			}
		};
		getView().asyncExec(r);
	}

	/**
	 * @see IExpressionsListener#expressionsChanged(IExpression[])
	 */
	public void expressionsChanged(final IExpression[] expressions) {
		Runnable r = new Runnable() {
			public void run() {
				getTreeViewer().getControl().setRedraw(false);
				for (int i = 0; i < expressions.length; i++) {
					IExpression expression = expressions[i];
					refresh(expression);
					// update details if selected
					IStructuredSelection selection = (IStructuredSelection)getViewer().getSelection();
					if (selection.size() == 1 && selection.getFirstElement().equals(expression)) {
						getVariablesView().populateDetailPane();	
					}
				}
				getTreeViewer().getControl().setRedraw(true);
			}
		};
		getView().asyncExec(r);			
	}
	
	/**
	 * Override the superclass method. Do nothing.
	 */
	protected void doHandleResumeEvent(DebugEvent event) {
	}
	/**
	 * @see org.eclipse.debug.internal.ui.views.variables.VariablesViewEventHandler#doHandleChangeEvent(org.eclipse.debug.core.DebugEvent)
	 */
	protected void doHandleChangeEvent(DebugEvent event) {
		if (event.getSource() instanceof IExpression) {
			refresh(event.getSource());
		} else if (event.getDetail() == DebugEvent.STATE) {
			// only process variable state changes
			if (event.getSource() instanceof IVariable) {
				refresh(event.getSource());
			}
		} else {
			refresh();
		}	
	}

}