/*******************************************************************************
 * Copyright (c) 2005 Oracle Corporation.
 * 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:
 *    Gerry Kessler - initial API and implementation
 *    Ian Trimble - JSFLibraryRegistry work
 *******************************************************************************/ 
package org.eclipse.jst.jsf.core.internal;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.ILog;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.InvalidRegistryObjectException;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.preferences.InstanceScope;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EPackage;
import org.eclipse.emf.ecore.xmi.XMLResource;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.ArchiveFile;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.JSFLibrary;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.JSFLibraryRegistry;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.JSFLibraryRegistryFactory;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.PluginProvidedJSFLibrary;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.adapter.MaintainDefaultImplementationAdapter;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.impl.JSFLibraryRegistryPackageImpl;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.util.JSFLibraryRegistryResourceFactoryImpl;
import org.eclipse.jst.jsf.core.internal.jsflibraryregistry.util.JSFLibraryRegistryResourceImpl;
import org.eclipse.jst.jsf.core.internal.provisional.jsflibraryregistry.PluginProvidedJSFLibraryCreationHelper;
import org.eclipse.ui.preferences.ScopedPreferenceStore;
import org.eclipse.wst.common.frameworks.internal.WTPPlugin;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;

/**
 * JSF Core plugin.
 * 
 * @author Gerry Kessler - Oracle, Ian Trimble - Oracle
 */
public class JSFCorePlugin extends WTPPlugin {
	/**
	 * The plugin id
	 */
	public static final String PLUGIN_ID = "org.eclipse.jst.jsf.core";//org.eclipse.jst.jsf.core.internal.JSFCorePlugin"; //$NON-NLS-1$

	/**
	 * The JSF facet identifier
	 */
	public static final String FACET_ID = "jst.jsf"; //$NON-NLS-1$
	
	// The shared instance.
	private static JSFCorePlugin plugin;

	// The workspace-relative part of the URL of the JSF Library Registry
	// persistence store.
	private static final String JSF_LIBRARY_REGISTRY_URL = ".metadata/.plugins/org.eclipse.jst.jsf.core/JSFLibraryRegistry.xml"; //$NON-NLS-1$

	// The NS URI of the JSF Library Registry's Ecore package. (Must match
	// setting on package in Ecore model.)
	private static final String JSF_LIBRARY_REGISTRY_NSURI = "http://www.eclipse.org/webtools/jsf/schema/jsflibraryregistry.xsd"; //$NON-NLS-1$

	/**
	 * The id of the library extension point
	 */
	public static final String LIB_EXT_PT = "jsfLibraries"; //$NON-NLS-1$

	// The JSF Library Registry EMF resource instance.
	private JSFLibraryRegistryResourceImpl jsfLibraryRegistryResource = null;

	// The JSF Library Registry instance.
	private JSFLibraryRegistry jsfLibraryRegistry = null;

    private IPreferenceStore  preferenceStore;

	/**
	 * The constructor.
	 */
	public JSFCorePlugin() {
		plugin = this;
	}

	/**
	 * This method is called upon plug-in activation
	 * @param context 
	 * @throws Exception 
	 */
	public void start(BundleContext context) throws Exception {
		super.start(context);
		loadJSFLibraryRegistry();
	}

	/**
	 * This method is called when the plug-in is stopped
	 * @param context 
	 * @throws Exception 
	 */
	public void stop(BundleContext context) throws Exception {
		saveJSFLibraryRegistry();
		super.stop(context);
		plugin = null;
	}

	/**
	 * Returns the shared instance.
	 * @return the shared instance
	 */
	public static JSFCorePlugin getDefault() {
		return plugin;
	}

	/**
	 * Returns the JSFLibraryRegistry EMF object.
	 * 
	 * @return the JSFLibraryRegistry EMF object.
	 */
	public JSFLibraryRegistry getJSFLibraryRegistry() {
		return jsfLibraryRegistry;
	}

	/**
	 * Loads the JSFLibraryRegistry EMF object from plugin-specfic workspace
	 * settings location. (Called from start(BundleContext).)
	 */
	public void loadJSFLibraryRegistry() {
		try {
			URL jsfLibRegURL = new URL(Platform.getInstanceLocation().getURL(), JSF_LIBRARY_REGISTRY_URL);
			URI jsfLibRegURI = URI.createURI(jsfLibRegURL.toString());
			EPackage.Registry.INSTANCE.put(JSF_LIBRARY_REGISTRY_NSURI, JSFLibraryRegistryPackageImpl.init());
			JSFLibraryRegistryResourceFactoryImpl resourceFactory = new JSFLibraryRegistryResourceFactoryImpl();
			jsfLibraryRegistryResource = (JSFLibraryRegistryResourceImpl)resourceFactory.createResource(jsfLibRegURI);
			try {
				Map options = new HashMap();
				//disable notifications during load to avoid changing stored default implementation
				options.put(XMLResource.OPTION_DISABLE_NOTIFY, Boolean.TRUE);
				jsfLibraryRegistryResource.load(options);
				jsfLibraryRegistry = (JSFLibraryRegistry)jsfLibraryRegistryResource.getContents().get(0);
				loadJSFLibraryExtensions();
			} catch(IOException ioe) {
				/**
				 * Remove the 3rd throwable parameter in the statement below 
				 * to surpress error stack in log file since it is only 
				 * informational.  Bug 144947.
				 */  
				//log(IStatus.INFO, Messages.JSFLibraryRegistry_NoLoadCreatingNew, ioe);
				log(IStatus.INFO, Messages.JSFLibraryRegistry_NoLoadCreatingNew);
				jsfLibraryRegistry = JSFLibraryRegistryFactory.eINSTANCE.createJSFLibraryRegistry();
				jsfLibraryRegistryResource.getContents().add(jsfLibraryRegistry);
				loadJSFLibraryExtensions();
			}
			//add adapter to maintain default implementation
			if (jsfLibraryRegistry != null) {
				jsfLibraryRegistry.eAdapters().add(MaintainDefaultImplementationAdapter.getInstance());
			}
		} catch(MalformedURLException mue) {
			log(IStatus.ERROR, Messages.JSFLibraryRegistry_ErrorCreatingURL, mue);
		}
	}

	/**
	 * Creates library registry items from extension points.
	 */
	private void loadJSFLibraryExtensions() {
		try {
			IExtensionPoint point = Platform.getExtensionRegistry().getExtensionPoint(JSFCorePlugin.PLUGIN_ID, JSFCorePlugin.LIB_EXT_PT);
			IExtension[] extensions = point.getExtensions();
			for (int i=0;i < extensions.length;i++){
				IExtension ext = extensions[i];
				for (int j=0;j < ext.getConfigurationElements().length;j++){
					PluginProvidedJSFLibraryCreationHelper newLibCreator = new PluginProvidedJSFLibraryCreationHelper(ext.getConfigurationElements()[j]);						
					JSFLibrary newLib = newLibCreator.create();
					
					/**
					 * Additional check on if a plug-in contributes jsflibraries is an expanded folder.
					 * Fix related to bug 144954.  
					 * 
					 * It would be ideal to check if a plug-in is distributed as a JAR 
					 * before a JSFLibrary is created.
					 * 
					 * This is a temporary solution since JARs in a JAR case is not 
					 * supported in this release.  Bug 14496.
					 */
					if (newLib != null && isJSFLibinExpandedFolder(newLib))
						jsfLibraryRegistry.addJSFLibrary(newLib);
				}
			}
		} catch (InvalidRegistryObjectException e) {
			log(IStatus.ERROR, Messages.JSFLibraryRegistry_ErrorLoadingFromExtPt, e);
		}
	}
	
	/**
	 * Saves the JSFLibraryRegistry EMF object from plugin-specfic workspace
	 * settings location. (Called from stop(BundleContext).)
	 * @return true if save is successful
	 */
	public boolean saveJSFLibraryRegistry() {
		boolean saved = false;
		if (jsfLibraryRegistryResource != null) {
			try {
				jsfLibraryRegistryResource.save(Collections.EMPTY_MAP);
				saved = true;
			} catch(IOException ioe) {
				log(IStatus.ERROR, Messages.JSFLibraryRegistry_ErrorSaving, ioe);
			}
		} else {
			log(IStatus.ERROR, Messages.JSFLibraryRegistry_ErrorSaving);
		}
		return saved;
	}

	/**
	 * @param e
	 * @param msg
	 */
	public static void log(final Exception e, final String msg) {
		final ILog log = getDefault().getLog();

		log.log(new Status(IStatus.ERROR, PLUGIN_ID, IStatus.OK, msg, e));
	}

	/**
	 * Logs using the default ILog implementation provided by getLog().
	 * 
	 * @param severity Severity (IStatus constant) of log entry
	 * @param message Human-readable message describing log entry
	 * @param ex Throwable instance (can be null)
	 */
	public static void log(int severity, String message, Throwable ex) {
		getDefault().getLog().log(new Status(severity, PLUGIN_ID, IStatus.OK, message, ex));
	}

	/**
	 * Logs using the default ILog implementation provided by getLog().
	 * 
	 * @param severity Severity (IStatus constant) of log entry
	 * @param message Human-readable message describing log entry
	 */
	public static void log(int severity, String message) {
		log(severity, message, null);
	}

    /**
     * Logs a message for this plugin
     * 
     * @param message
     * @param t
     */
    public static void log(String message, Throwable t)
    {
        ILog log = plugin.getLog();
        log.log(
           new Status(
             IStatus.ERROR, plugin.getBundle().getSymbolicName(), 0, message, t));
    }
    
	public String getPluginID() {
		return PLUGIN_ID;
	}
	
	/**
	 * To check if a jsflibraries contribution plug-in is 
	 * distributed in a JAR.
	 * 
	 * This is temporary for bug 144954.  Need to be removed when 
	 * fixing 144996.
	 *    
	 * @param jsflib
	 * @return true if jsflib is in the expanded folder
	 */
	private boolean isJSFLibinExpandedFolder(JSFLibrary jsflib) {
		boolean exists = false;
		if (jsflib instanceof PluginProvidedJSFLibrary) { 		// No need to check probably  
			if (jsflib.getArchiveFiles().size() > 0) {
				ArchiveFile ar = (ArchiveFile) jsflib.getArchiveFiles().get(0);
				String resolvedSourceLocation = ar.getResolvedSourceLocation();
				if (resolvedSourceLocation != null) {
					exists = new File(resolvedSourceLocation).exists();
				}		
			}			
		}		
		return exists;
	}

    /**
     * @return all registered symbol source providers
     */
    public synchronized static Map getVariableResolvers()
    {
        if (_registeredVariableResolvers == null)
        {
            registerVariableResolverProviders();
            if (_registeredVariableResolvers == null)
            {
                throw new AssertionError("registerProviders failed");
            }
        }
        return Collections.unmodifiableMap(_registeredVariableResolvers);
    }
    
    private static Map    _registeredVariableResolvers;
    private final static String VARIABLE_RESOLVER_EXT_POINT_NAME = "variableresolver";
    
    private static void registerVariableResolverProviders()
    {
        _registeredVariableResolvers = new HashMap();
        loadRegisteredExtensions(VARIABLE_RESOLVER_EXT_POINT_NAME,
                                _registeredVariableResolvers,
                                 "variableresolver");
    }
    
    /**
     * @return a map of all registered property resolvers by id
     */
    public synchronized static Map getPropertyResolvers()
    {
        if (_registeredPropertyResolvers == null)
        {
            registerPropertyResolverProviders();
            if (_registeredPropertyResolvers == null)
            {
                throw new AssertionError("registerProviders failed");
            }
        }
        return Collections.unmodifiableMap(_registeredPropertyResolvers);
    }
    
    private static Map    _registeredPropertyResolvers;
    private final static String PROPERTY_RESOLVER_EXT_POINT_NAME = 
                                                             "propertyresolver";
    
    private static void registerPropertyResolverProviders()
    {
        _registeredPropertyResolvers = new HashMap();
        loadRegisteredExtensions(PROPERTY_RESOLVER_EXT_POINT_NAME,
                                _registeredPropertyResolvers,
                                 "propertyresolver");
    }
    
    
    /**
     * @return a map of all registered method resolvers by id
     */
    public synchronized static Map getMethodResolvers()
    {
        if (_registeredMethodResolvers == null)
        {
            registerMethodResolverProviders();
            if (_registeredMethodResolvers == null)
            {
                throw new AssertionError("registerProviders failed");
            }
        }
        return Collections.unmodifiableMap(_registeredMethodResolvers);
    }

    private static Map     _registeredMethodResolvers;
    private final static String METHOD_RESOLVER_EXT_POINT_NAME = 
                                                               "methodresolver";
    
    private static void registerMethodResolverProviders()
    {
        _registeredMethodResolvers = new HashMap();
        loadRegisteredExtensions(METHOD_RESOLVER_EXT_POINT_NAME,
                _registeredMethodResolvers,
                 "methodresolver");

    }

    /**
     * @return a map of all registered external context providers by id
     */
    public synchronized static Map getExternalContextProviders()
    {
        if (_registeredExternalContextProviders == null)
        {
            registerExternalContextProviders();
            if (_registeredExternalContextProviders == null)
            {
                throw new AssertionError("registerProviders failed");
            }
        }
        return Collections.unmodifiableMap(_registeredExternalContextProviders);
    }
    
    private static Map     _registeredExternalContextProviders;
    private final static String EXTERNAL_CONTEXT_EXT_POINT_NAME = 
                                                               "externalcontext";

    private static void registerExternalContextProviders()
    {
        _registeredExternalContextProviders = new HashMap();
        loadRegisteredExtensions(EXTERNAL_CONTEXT_EXT_POINT_NAME,
                                 _registeredExternalContextProviders,
                                 "externalcontext");
    }
    
    private static void loadRegisteredExtensions(final String extName,
                                                 final Map    registry,
                                                 final String elementName)
    {
        final IExtensionPoint point = Platform.getExtensionRegistry().
        getExtensionPoint(plugin.getBundle().getSymbolicName(), 
                extName);
        final IExtension[] extensions = point.getExtensions();

        for (int i = 0; i < extensions.length; i++)
        {
            final IExtension extension = extensions[i];
            final IConfigurationElement[] elements = 
                extension.getConfigurationElements();
            final String bundleId = extension.getContributor().getName();
            
            for (int j = 0; j < elements.length; j++)
            {
                final IConfigurationElement element = elements[j];
                if (elementName.equals(element.getName())
                        && element.getAttribute("class") != null
                        && element.getAttribute("id") != null)
                {
                    final String factoryClassName = element.getAttribute("class");
                    final String id = element.getAttribute("id");
                    final Bundle bundle = Platform.getBundle(bundleId);
                    
                    if (bundle != null)
                    {
                        try
                        {
                            final Class factoryClass = 
                                bundle.loadClass(factoryClassName);
                            
                            final Object variableResolver= 
                                factoryClass.newInstance();
    
                            registry.put(id, variableResolver);
                        }
                        catch (Exception e)
                        {
                            final ILog        logger_ = getDefault().getLog();
                            logger_.log(new Status(IStatus.ERROR, plugin.getBundle()
                                    .getSymbolicName(), 0, 
                                    "Error loading property resolver provider extension point",e));
                        }
                    }
                }
            }
        }
    }
    
    /**
     * @return the preference store for this bundle
     * TODO: this is copied from AbstractUIPlugin; need to upgrade to new IPreferencesService
     */
    public IPreferenceStore getPreferenceStore() {
        // Create the preference store lazily.
        if ( this.preferenceStore == null) {
            this.preferenceStore = new ScopedPreferenceStore(new InstanceScope(),getBundle().getSymbolicName());

        }
        return this.preferenceStore;
    }
}