/*******************************************************************************
 * Copyright (c) 2008-2011 Chair for Applied Software Engineering,
 * Technische Universitaet Muenchen.
 * 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:
 * wesendon
 * boehlke
 ******************************************************************************/
package org.eclipse.emf.emfstore.internal.server.core;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.EnumMap;
import java.util.LinkedHashSet;
import java.util.Set;

import org.eclipse.emf.emfstore.common.extensionpoint.ESExtensionElement;
import org.eclipse.emf.emfstore.common.extensionpoint.ESExtensionPoint;
import org.eclipse.emf.emfstore.internal.common.model.util.ModelUtil;
import org.eclipse.emf.emfstore.internal.server.EMFStore;
import org.eclipse.emf.emfstore.internal.server.accesscontrol.AuthorizationControl;
import org.eclipse.emf.emfstore.internal.server.core.helper.EmfStoreMethod;
import org.eclipse.emf.emfstore.internal.server.core.helper.EmfStoreMethod.MethodId;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.EMFStorePropertiesSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.EPackageSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.FileTransferSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.HistorySubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.ProjectPropertiesSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.ProjectSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.UserSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.core.subinterfaces.VersionSubInterfaceImpl;
import org.eclipse.emf.emfstore.internal.server.exceptions.FatalESException;
import org.eclipse.emf.emfstore.internal.server.model.ServerSpace;
import org.eclipse.emf.emfstore.server.exceptions.ESException;
import org.eclipse.emf.emfstore.server.observer.ESServerCallObserver;

/**
 * This is the main implementation of {@link EMFStore}.
 * 
 * @author wesendon
 * @see EMFStore
 */
// TODO: internal
public class EMFStoreImpl extends AbstractEmfstoreInterface implements InvocationHandler {

	/**
	 * Represents a method in a subinterface.
	 * 
	 * @author boehlke
	 */
	private class SubInterfaceMethod {
		private final AbstractSubEmfstoreInterface iface;
		private final Method method;

		public SubInterfaceMethod(AbstractSubEmfstoreInterface iface, Method m) {
			method = m;
			this.iface = iface;
		}

		/**
		 * @return the iface
		 */
		public AbstractSubEmfstoreInterface getIface() {
			return iface;
		}

		/**
		 * @return the method
		 */
		public Method getMethod() {
			return method;
		}
	}

	private EnumMap<MethodId, SubInterfaceMethod> subInterfaceMethods;
	private final Set<ESServerCallObserver> serverCallObservers;

	/**
	 * Default constructor.
	 * 
	 * @param serverSpace
	 *            the serverspace
	 * @param authorizationControl
	 *            the accesscontrol
	 * @throws FatalESException
	 *             in case of failure
	 */
	public EMFStoreImpl(ServerSpace serverSpace, AuthorizationControl authorizationControl)
		throws FatalESException {
		super(serverSpace, authorizationControl);
		serverCallObservers = initServerCallObservers();
	}

	/**
	 * 
	 */
	private Set<ESServerCallObserver> initServerCallObservers() {
		final Set<ESServerCallObserver> result = new LinkedHashSet<ESServerCallObserver>();
		for (final ESExtensionElement e : new ESExtensionPoint("org.eclipse.emf.emfstore.server.serverCallObserver")
			.getExtensionElements()) {
			final ESServerCallObserver observer = e.getClass("class", ESServerCallObserver.class);
			if (observer != null) {
				result.add(observer);
			}
		}
		return result;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void initSubInterfaces() throws FatalESException {
		subInterfaceMethods = new EnumMap<MethodId, SubInterfaceMethod>(MethodId.class);
		addSubInterface(new HistorySubInterfaceImpl(this));
		addSubInterface(new ProjectSubInterfaceImpl(this));
		addSubInterface(new UserSubInterfaceImpl(this));
		addSubInterface(new VersionSubInterfaceImpl(this));
		addSubInterface(new FileTransferSubInterfaceImpl(this));
		addSubInterface(new ProjectPropertiesSubInterfaceImpl(this));
		addSubInterface(new EMFStorePropertiesSubInterfaceImpl(this));
		addSubInterface(new EPackageSubInterfaceImpl(this));
	}

	@Override
	protected void addSubInterface(AbstractSubEmfstoreInterface iface) {
		super.addSubInterface(iface);
		for (final Method method : iface.getClass().getMethods()) {
			final EmfStoreMethod implSpec = method.getAnnotation(EmfStoreMethod.class);
			if (implSpec != null) {
				subInterfaceMethods.put(implSpec.value(), new SubInterfaceMethod(iface, method));
			}
		}
	}

	/**
	 * 
	 * {@inheritDoc}
	 * 
	 * @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
	 */
	public Object invoke(Object obj, final Method method, final Object[] args) throws ESException {
		final MethodInvocation methodInvocation = new MethodInvocation(method.getName(), args);
		getAuthorizationControl().checkAccess(methodInvocation);

		notifyServerCallObservers(new ServerCallObserverNotifier() {
			public void notify(ESServerCallObserver observer) {
				observer.notifyPreServerCallExecution(method, args);
			}
		});
		final SubInterfaceMethod subIfaceMethod = subInterfaceMethods.get(methodInvocation.getType());
		try {
			final Object result = subIfaceMethod.getIface().execute(subIfaceMethod.getMethod(), args);
			notifyServerCallObservers(new ServerCallObserverNotifier() {
				public void notify(ESServerCallObserver observer) {
					observer.notifyPostServerCallExecution(method, args, result);
				}
			});
			return result;
			// notify observers about exceptions and rethrow exception
		} catch (final ESException esException) {
			notifyServerCallObservers(new ServerCallObserverNotifier() {
				public void notify(ESServerCallObserver observer) {
					observer.notifyServerCallExecutionESExceptionFailure(method, args, esException);
				}
			});
			throw esException;
			// BEGIN SUPRESS CATCH EXCEPTION
		} catch (final RuntimeException runtimeException) {
			// END SUPRESS CATCH EXCEPTION
			notifyServerCallObservers(new ServerCallObserverNotifier() {
				public void notify(ESServerCallObserver observer) {
					observer.notifyServerCallExecutionRuntimeExceptionFailure(method, args, runtimeException);
				}
			});
			throw runtimeException;
		}
	}

	/**
	 * Notify the observers with the given notifier.
	 * 
	 * @param serverCallObserverNotifier the notifier
	 */
	private void notifyServerCallObservers(ServerCallObserverNotifier serverCallObserverNotifier) {
		for (final ESServerCallObserver callObserver : serverCallObservers) {
			try {
				serverCallObserverNotifier.notify(callObserver);
				// BEGIN SUPRESS CATCH EXCEPTION
			} catch (final RuntimeException runtimeException) {
				// END SUPRESS CATCH EXCEPTION
				ModelUtil.logWarning("Server Call Observer Notification failed with exception!", runtimeException);
			}
		}
	}

	/**
	 * creates a dynamic proxy backed by EmfStoreImpl.
	 * 
	 * @param serverSpace the server space
	 * @param accessControl an access control instance
	 * @return an instance of emfstore
	 * @throws IllegalArgumentException thrown by Proxy.newInstance
	 * @throws FatalESException thrown if something fatal happens
	 */
	public static EMFStore createInterface(ServerSpace serverSpace, AuthorizationControl accessControl)
		throws IllegalArgumentException, FatalESException {
		return (EMFStore) Proxy.newProxyInstance(EMFStoreImpl.class.getClassLoader(), new Class[] { EMFStore.class },
			new EMFStoreImpl(serverSpace, accessControl));
	}

}