package org.eclipse.jst.jsf.facelet.core.internal.metadata;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.content.IContentType;
import org.eclipse.jface.util.SafeRunnable;
import org.eclipse.jst.jsf.common.metadata.internal.AbstractMetaDataLocator;
import org.eclipse.jst.jsf.common.metadata.internal.IMetaDataChangeNotificationEvent;
import org.eclipse.jst.jsf.common.metadata.internal.IMetaDataLocator;
import org.eclipse.jst.jsf.common.metadata.internal.IMetaDataObserver;
import org.eclipse.jst.jsf.common.metadata.internal.IMetaDataSourceModelProvider;
import org.eclipse.jst.jsf.common.metadata.internal.IPathSensitiveMetaDataLocator;
import org.eclipse.jst.jsf.common.metadata.internal.MetaDataChangeNotificationEvent;
import org.eclipse.jst.jsf.common.runtime.internal.view.model.common.Namespace;
import org.eclipse.jst.jsf.core.internal.CompositeTagRegistryFactory;
import org.eclipse.jst.jsf.core.internal.CompositeTagRegistryFactory.TagRegistryIdentifier;
import org.eclipse.jst.jsf.core.metadata.internal.INamespaceModelProvider;
import org.eclipse.jst.jsf.designtime.internal.view.model.ITagRegistry;
import org.eclipse.jst.jsf.designtime.internal.view.model.ITagRegistry.ITagRegistryListener;
import org.eclipse.jst.jsf.designtime.internal.view.model.ITagRegistry.TagRegistryChangeEvent;
import org.eclipse.jst.jsf.facelet.core.internal.FaceletCorePlugin;


/**
 * Locates Facelet {@link Namespace} metadata
 */
public class FaceletNamespaceMetaDataLocator 
		extends AbstractMetaDataLocator
		implements IPathSensitiveMetaDataLocator, ITagRegistryListener {

	private static final IContentType FACELET_CONTENTTYPE = Platform.getContentTypeManager().findContentTypeFor("foo.xhtml"); //$NON-NLS-1$
	private IProject _project;
	private ITagRegistry _reg; 

	public List<IMetaDataSourceModelProvider> locateMetaDataModelProviders(final String uri) {
		final List<IMetaDataSourceModelProvider> providers = new ArrayList<IMetaDataSourceModelProvider>();
		if (_reg != null) {
			final Namespace ns = _reg.getTagLibrary(uri);
		    
			if (ns != null) {
		    	providers.add(new NamespaceSourceModel(ns));
		    }
		}
        return providers;
	}

	public void startLocating() {
		final TagRegistryIdentifier tagRegId = new TagRegistryIdentifier(_project, FACELET_CONTENTTYPE);
		_reg = CompositeTagRegistryFactory.getInstance().getRegistry(tagRegId);
		if (_reg != null) {
			_reg.addListener(this);
		}

	}

	public void stopLocating() {
		if (_reg != null) {
			_reg.removeListener(this);
			_reg = null;
		}
	}

	public void setProjectContext(final IProject project) {
		_project = project;
	}

	public void registryChanged(final TagRegistryChangeEvent changeEvent) {
		for (final Namespace ns : changeEvent.getAffectedObjects()) {
			if (adaptTagRegistryEvent(changeEvent) != IMetaDataChangeNotificationEvent.ADDED) {
				final IMetaDataChangeNotificationEvent mdEvent = new MetaDataChangeNotificationEvent(this, ns.getNSUri(), adaptTagRegistryEvent(changeEvent));
				fireEvent(mdEvent);
			}
		}
	}

	private int adaptTagRegistryEvent(final TagRegistryChangeEvent event) {
		switch (event.getType()) {
		case ADDED_NAMESPACE:
			return IMetaDataChangeNotificationEvent.ADDED;
		case REMOVED_NAMESPACE:			
		case REGISTRY_DISPOSED:
			return IMetaDataChangeNotificationEvent.REMOVED;
		default:
			return IMetaDataChangeNotificationEvent.CHANGED;
		}
	}
	
	private void fireEvent(final IMetaDataChangeNotificationEvent event) {
		SafeRunnable.run(new ISafeRunnable(){

			public void handleException(Throwable exception) {
				FaceletCorePlugin.log("Error while firing metadataChangeNotificationEvent" , exception)	; //$NON-NLS-1$
			}
	
			public void run() throws Exception {				
				for (final IMetaDataObserver observer : getObservers()){					
					observer.notifyMetadataChanged(event);
				}
			}
	
		});
	}
	
	private class NamespaceSourceModel implements INamespaceModelProvider {

		private Namespace ns;
		private IMetaDataLocator locator;

		NamespaceSourceModel(final Namespace ns){
			this.ns = ns;
		}
		
		public Object getSourceModel() {
			return ns;
		}

		public IMetaDataLocator getLocator() {
			return locator;
		}

		public void setLocator(IMetaDataLocator locator) {
			this.locator = locator;			
		}

		public Object getAdapter(Class klass) {
			return null;
		}

		public Namespace getNamespace() {
			return ns;
		}
	}

}