package org.eclipse.jst.j2ee.internal.webservice.startup;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceChangeEvent;
import org.eclipse.core.resources.IResourceChangeListener;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.IResourceDeltaVisitor;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.ui.IStartup;
import org.eclipse.wst.common.project.facet.core.internal.FacetedProjectPropertyTester;

public class WebserviceListener implements IStartup, IResourceChangeListener, IResourceDeltaVisitor {
	
	private boolean listening = false;
	    
    /* The constants/facets/file extns are duplicated here to avoid loading plugins */
	private static final String PROJECT_FACET = "projectFacet"; //$NON-NLS-1$     
    
	private static final String EAR_FACET = "jst.ear"; //$NON-NLS-1$ 
    private static final String APPCLIENT_FACET = "jst.appclient"; //$NON-NLS-1$ 
    private static final String WEB_FACET = "jst.web"; //$NON-NLS-1$ 
    private static final String EJB_FACET = "jst.ejb"; //$NON-NLS-1$ 
    
	private static final String WSDL_EXT = "wsdl"; //$NON-NLS-1$
	private static final String WSIL_EXT = "wsil"; //$NON-NLS-1$
	private static final String WEB_SERVICES_CLIENT_SHORTNAME    = "webservicesclient.xml"; //$NON-NLS-1$
	private static final String WEB_SERVICES_DD_URI			= 	"webservices.xml"; //$NON-NLS-1$
	
    private static final FacetedProjectPropertyTester facetPropertyTester = new FacetedProjectPropertyTester();

    private static WebserviceListener INSTANCE;
    
    public static WebserviceListener getInstance() {
		return INSTANCE;
	}
	/**
	 * @param project
	 * @return
	 * method copied from WebServicesViewerSynchronization for performance reasons (not load plugins)
	 */
	private static final boolean isInteresting(IProject project) {
		return hasFacet(project, WEB_FACET) || 
			hasFacet(project, EJB_FACET) || 
			hasFacet(project, APPCLIENT_FACET);
	}
	/**
	 * @param element
	 * @param facet
	 * @return
	 * method copied from WebServicesViewerSynchronization for performance reasons (not load plugins)
	 */
	private static final boolean hasFacet(Object element, String facet) {
		return facetPropertyTester.test(element, PROJECT_FACET, new Object[] {}, facet);
	}
	
	/**
	 * @param aFile
	 * @return
	 * method copied from WebServicesManager for performance reasons (not load plugins)
	 */
	private static final boolean isFileInteresting(IFile aFile) {
		if (aFile != null && aFile.getFileExtension() != null) {
			String extension = aFile.getFileExtension();
			return extension.equals(WSDL_EXT) || extension.equals(WSIL_EXT) 
			|| aFile.getName().equals(WEB_SERVICES_CLIENT_SHORTNAME) 
			|| aFile.getName().equals(WEB_SERVICES_DD_URI);
		}
		return false;
	}

	
	public boolean isListening() {
		return listening;
	}
	public void earlyStartup() {
		INSTANCE = this;
		startListening();
	}

	public void resourceChanged(IResourceChangeEvent event) {
		try {
			event.getDelta().accept(this);
		} catch (CoreException e) {
		} 
	}

	public boolean visit(IResourceDelta delta) throws CoreException { 
		
		IResource resource = delta.getResource();
		switch (resource.getType()) {
			case IResource.ROOT :
				return true;
			case IResource.PROJECT: 
				if(isListening() &&  (delta.getKind() == IResourceDelta.ADDED || delta.getKind() == IResourceDelta.CHANGED)){
					if(isInteresting(resource.getProject())) {
						return true;
					}
				}
				break;
			case IResource.FOLDER :
				if(isListening() && (delta.getKind() == IResourceDelta.ADDED || delta.getKind() == IResourceDelta.CHANGED)) {
					return true;
				}
				break;
			case IResource.FILE :
				if(isListening() && delta.getKind() == IResourceDelta.ADDED) {
					if(isFileInteresting((IFile)resource)){
						stopListening();
						// this will cause the plug-in to start our goal was to delay it until now
						if(org.eclipse.jst.j2ee.internal.webservice.WebServiceViewerSynchronization.isThereWebServicesPreferenceSet()){
							org.eclipse.jst.j2ee.internal.webservice.WebServiceViewerSynchronization.setAreThereWebServices(true);
						}
					}
				}				
			default :
				break;
		}
		
		return false;
	}
	
	public void startListening() {
		ResourcesPlugin.getWorkspace().addResourceChangeListener(this, IResourceChangeEvent.POST_CHANGE);
		listening = true;
	}

	public void stopListening() {
		ResourcesPlugin.getWorkspace().removeResourceChangeListener(this);
		listening = false;
	}
}