//------------------------------------------------------------------------------
// Copyright (c) 2005, 2007 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 implementation
//------------------------------------------------------------------------------
package org.eclipse.epf.authoring.ui.providers;

import org.eclipse.core.resources.IMarker;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceStatus;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.epf.authoring.ui.AuthoringUIImages;
import org.eclipse.epf.authoring.ui.AuthoringUIPlugin;
import org.eclipse.epf.authoring.ui.internal.IProblemChangedListener;
import org.eclipse.epf.authoring.ui.internal.ImageDescriptorRegistry;
import org.eclipse.epf.authoring.ui.internal.ImageImageDescriptor;
import org.eclipse.epf.authoring.ui.internal.MethodElementImageDescriptor;
import org.eclipse.epf.persistence.util.PersistenceUtil;
import org.eclipse.epf.uma.MethodElement;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.IBaseLabelProvider;
import org.eclipse.jface.viewers.IDecoration;
import org.eclipse.jface.viewers.ILabelDecorator;
import org.eclipse.jface.viewers.ILabelProviderListener;
import org.eclipse.jface.viewers.ILightweightLabelDecorator;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;

/**
 * Code taken from org.eclipse.jdt.ui.ProblemsLabelDecorator 
 *
 */
public class ProblemsLabelDecorator implements ILabelDecorator, ILightweightLabelDecorator {
	
	/**
	 * This is a special <code>LabelProviderChangedEvent</code> carrying additional 
	 * information whether the event origins from a maker change.
	 * <p>
	 * <code>ProblemsLabelChangedEvent</code>s are only generated by <code>
	 * ProblemsLabelDecorator</code>s.
	 * </p>
	 */
	public static class ProblemsLabelChangedEvent extends LabelProviderChangedEvent {

		private static final long serialVersionUID= 1L;
		
		private boolean fMarkerChange;

		/**
		 * Note: This constructor is for internal use only. Clients should not call this constructor.
		 * 
		 * @param eventSource the base label provider
		 * @param changedResource the changed resources
		 * @param isMarkerChange <code>true<code> if the change is a marker change; otherwise
		 *  <code>false</code> 
		 */
		public ProblemsLabelChangedEvent(IBaseLabelProvider eventSource, IResource[] changedResource, boolean isMarkerChange) {
			super(eventSource, changedResource);
			fMarkerChange= isMarkerChange;
		}
		
		/**
		 * Returns whether this event origins from marker changes. If <code>false</code> an annotation 
		 * model change is the origin. In this case viewers not displaying working copies can ignore these 
		 * events.
		 * 
		 * @return if this event origins from a marker change.
		 */
		public boolean isMarkerChange() {
			return fMarkerChange;
		}

	}

	private static final int ERRORTICK_ERROR= MethodElementImageDescriptor.ERROR;	

	private ImageDescriptorRegistry fRegistry;
	private boolean fUseNewRegistry= false;
	private IProblemChangedListener fProblemChangedListener;
	
	private ListenerList fListeners;

	/**
	 * Creates a new <code>ProblemsLabelDecorator</code>.
	 */
	public ProblemsLabelDecorator() {
		this(null);
		fUseNewRegistry= true;
	}
	
	/**
	 * Note: This constructor is for internal use only. Clients should not call this constructor.
	 * 
	 * @param registry The registry to use or <code>null</code> to use the Java plugin's
	 *  image registry
	 */
	public ProblemsLabelDecorator(ImageDescriptorRegistry registry) {
		fRegistry= registry;
		fProblemChangedListener= null;
	}
	
	private ImageDescriptorRegistry getRegistry() {
		if (fRegistry == null) {
			fRegistry= fUseNewRegistry ? new ImageDescriptorRegistry() : AuthoringUIPlugin.getImageDescriptorRegistry();
		}
		return fRegistry;
	}
	

	/* (non-Javadoc)
	 * @see ILabelDecorator#decorateText(String, Object)
	 */
	public String decorateText(String text, Object element) {
		return text;
	}	

	/* (non-Javadoc)
	 * @see ILabelDecorator#decorateImage(Image, Object)
	 */
	public Image decorateImage(Image image, Object obj) {
		int adornmentFlags= computeAdornmentFlags(obj);
		if (adornmentFlags != 0) {
			ImageDescriptor baseImage= new ImageImageDescriptor(image);
			Rectangle bounds= image.getBounds();
			return getRegistry().get(new MethodElementImageDescriptor(baseImage, adornmentFlags, new Point(bounds.width, bounds.height)));
		}
		return image;
	}

	/**
	 * Note: This method is for internal use only. Clients should not call this method.
	 * 
	 * @param obj the element to compute the flags for
	 * 
	 * @return the adornment flags
	 */
	protected int computeAdornmentFlags(Object obj) {
		try {
			if (obj instanceof MethodElement) {
				return getErrorTicksFromMarkers(PersistenceUtil.getWorkspaceResource(obj), IResource.DEPTH_INFINITE);
			} else if (obj instanceof IResource) {
				return getErrorTicksFromMarkers((IResource) obj, IResource.DEPTH_INFINITE);
			}
		} catch (CoreException e) {
			if (e.getStatus().getCode() == IResourceStatus.MARKER_NOT_FOUND) {
				return 0;
			}
			
			AuthoringUIPlugin.log(e);
		}
		return 0;
	}

	private int getErrorTicksFromMarkers(IResource res, int depth) throws CoreException {
		if (res == null || !res.isAccessible()) {
			return 0;
		}
		int info= 0;
		
		IMarker[] markers= res.findMarkers(IMarker.PROBLEM, true, depth);
		if (markers != null) {
			for (int i= 0; i < markers.length && (info != ERRORTICK_ERROR); i++) {
				IMarker curr= markers[i];
				int priority= curr.getAttribute(IMarker.SEVERITY, -1);
				if (priority == IMarker.SEVERITY_ERROR) {
					info= ERRORTICK_ERROR;
				}
			}			
		}
		return info;
	}
	
	/* (non-Javadoc)
	 * @see IBaseLabelProvider#dispose()
	 */
	public void dispose() {
		if (fProblemChangedListener != null) {
			AuthoringUIPlugin.getDefault().getProblemMarkerManager().removeListener(fProblemChangedListener);
			fProblemChangedListener= null;
		}
		if (fRegistry != null && fUseNewRegistry) {
			fRegistry.dispose();
		}
	}

	/* (non-Javadoc)
	 * @see IBaseLabelProvider#isLabelProperty(Object, String)
	 */
	public boolean isLabelProperty(Object element, String property) {
		return true;
	}
	
	/* (non-Javadoc)
	 * @see IBaseLabelProvider#addListener(ILabelProviderListener)
	 */
	public void addListener(ILabelProviderListener listener) {
		if (fListeners == null) {
			fListeners= new ListenerList();
		}
		fListeners.add(listener);
		if (fProblemChangedListener == null) {
			fProblemChangedListener= new IProblemChangedListener() {
				public void problemsChanged(IResource[] changedResources, boolean isMarkerChange) {
					fireProblemsChanged(changedResources, isMarkerChange);
				}
			};
			AuthoringUIPlugin.getDefault().getProblemMarkerManager().addListener(fProblemChangedListener);
		}
	}	

	/* (non-Javadoc)
	 * @see IBaseLabelProvider#removeListener(ILabelProviderListener)
	 */
	public void removeListener(ILabelProviderListener listener) {
		if (fListeners != null) {
			fListeners.remove(listener);
			if (fListeners.isEmpty() && fProblemChangedListener != null) {
				AuthoringUIPlugin.getDefault().getProblemMarkerManager().removeListener(fProblemChangedListener);
				fProblemChangedListener= null;
			}
		}
	}
	
	private void fireProblemsChanged(IResource[] changedResources, boolean isMarkerChange) {
		if (fListeners != null && !fListeners.isEmpty()) {
			LabelProviderChangedEvent event= new ProblemsLabelChangedEvent(this, changedResources, isMarkerChange);
			Object[] listeners= fListeners.getListeners();
			for (int i= 0; i < listeners.length; i++) {
				((ILabelProviderListener) listeners[i]).labelProviderChanged(event);
			}
		}
	}
		
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ILightweightLabelDecorator#decorate(java.lang.Object, org.eclipse.jface.viewers.IDecoration)
	 */
	public void decorate(Object element, IDecoration decoration) { 
		int adornmentFlags= computeAdornmentFlags(element);
		if (adornmentFlags == ERRORTICK_ERROR) {
			decoration.addOverlay(AuthoringUIImages.IMG_DESC_OVR_ERROR);
		}
	}

}