/*=============================================================================#
 # Copyright (c) 2009, 2018 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.rj.servi;

import java.net.MalformedURLException;
import java.net.UnknownHostException;
import java.rmi.NotBoundException;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.util.NoSuchElementException;

import javax.rmi.ssl.SslRMIClientSocketFactory;
import javax.security.auth.login.LoginException;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.rmi.RMIAddress;
import org.eclipse.statet.jcommons.status.ErrorStatus;
import org.eclipse.statet.jcommons.status.StatusException;

import org.eclipse.statet.rj.RjException;
import org.eclipse.statet.rj.server.RjsComConfig;
import org.eclipse.statet.rj.servi.node.RServiNodeManager;
import org.eclipse.statet.rj.servi.node.RServiPool;


/**
 * The class provides utility methods for the work with {@link RServi}.
 * <p>
 * It is not intend to instance the class.</p>
 */
@NonNullByDefault
public class RServiUtils {
	
	
	public static final String RJ_SERVI_ID= "org.eclipse.statet.rj.servi";
	public static final String RJ_CLIENT_ID= "org.eclipse.statet.rj.client";
	
	
	/**
	 * Requests a {@link RServi} instance from a pool. The pool must be accessible
	 * via RMI under the given address.
	 * <p>
	 * The R services returned by this method are available for exclusive usage
	 * by the caller (consumer). The consumer is responsible to return it to the pool
	 * by {@link RServi#close() closing} the RServi.
	 * 
	 * For SSL connections, use the prefix <code>ssl:</code>. Note that SSL requires
	 * the configuration of keystore and truststore at server and client side.
	 * 
	 * @param address the RMI address of the pool
	 * @param name a name which can be used to identify the client
	 * @return a reference to the RServi instance
	 * @throws StatusException if the operation was failed; the status
	 *     of the exception contains detail about the cause
	 * @throws NoSuchElementException if there is currently no free RServi
	 *     instance available. A later call with the same configuration
	 *     can be successfully.
	 * @throws LoginException if the RServi request requires authentication
	 */
	public static RServi getRServi(final String address, final String name)
			throws StatusException, NoSuchElementException, LoginException {
		try {
			RjsComConfig.setRMIClientSocketFactory(null);
			RServiPool pool;
			try {
				final RMIAddress rmiAddress= new RMIAddress(address);
				final Registry registry= LocateRegistry.getRegistry(rmiAddress.getHost(), rmiAddress.getPort(),
						(rmiAddress.isSSL()) ? new SslRMIClientSocketFactory() : null );
				pool= (RServiPool) registry.lookup(rmiAddress.getName());
			}
			catch (final MalformedURLException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"Invalid address for the RServi pool.",
						e ));
			}
			catch (final UnknownHostException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"Invalid address for the RServi pool.",
						e ));
			}
			catch (final NotBoundException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"The address does not point to a valid RServi pool.",
						e ));
			}
			catch (final ClassCastException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"The address does not point to a valid/compatible RServi pool.",
						e ));
			}
			catch (final RemoteException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"Failed looking for RServi pool in the RMI registry.",
						e ));
			}
			try {
				return pool.getRServi(name, null);
			}
			catch (final RjException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"Failed getting an RServi instance from the RServi pool.",
						e ));
			}
			catch (final RemoteException e) {
				throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
						"Failed looking for RServi pool in the RMI registry.",
						e ));
			}
		}
		finally {
			RjsComConfig.clearRMIClientSocketFactory();
		}
	}
	
	/**
	 * Requests a {@link RServi} instance from the given manager. The manager must be
	 * configured and started.
	 * <p>
	 * The R services returned by this method are available for exclusive usage
	 * by the caller (consumer). The consumer is responsible to return it to the manager
	 * by {@link RServi#close() closing} the RServi.
	 * 
	 * @param manager manager for RServi node(s)
	 * @param name a name which can be used to identify the client
	 * @return a reference to the RServi instance
	 * @throws StatusException if the operation was failed; the status
	 *     of the exception contains detail about the cause
	 * @throws NoSuchElementException if there is currently no free RServi
	 *     instance available. A later call with the same configuration
	 *     can be successfully.
	 */
	public static RServi getRServi(final RServiNodeManager manager, final String name)
			throws StatusException, NoSuchElementException {
		if (manager == null) {
			throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
					"RServi is not available." ));
		}
		try {
			return manager.getRServi(name);
		}
		catch (final RjException e) {
			throw new StatusException(new ErrorStatus(RJ_SERVI_ID,
					"Failed getting an RServi instance.",
					e ));
		}
	}
	
	
	private RServiUtils() {
	}
	
}