/*=============================================================================#
 # Copyright (c) 2009, 2020 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.internal.ide.core;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.jsch.core.IJSchLocation;
import org.eclipse.jsch.core.IJSchService;

import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;

import org.eclipse.statet.jcommons.lang.Disposable;

import org.eclipse.statet.ecommons.net.ssh.core.ISshSessionService;

import org.eclipse.statet.base.core.StatetCore;


/**
 * SSH session service implementation.
 * 
 * Don't forget to dispose to close the open connections.
 */
public class SshSessionManager implements ISshSessionService, Disposable {
	
	
	private static final int SSH_TIMEOUT= 60000;
	
	
	private Map<String, Session> fPool;
	
	
	public SshSessionManager() {
		this.fPool= new HashMap<>();
	}
	
	
	@Override
	public Session getSshSession(final String username, final String host, final int port,
			final IProgressMonitor monitor) throws CoreException {
		final String key= username + '@' + host + ':' + Integer.toString((port > 0) ? port : 22);
		Session session= this.fPool.get(key);
		try {
			final IJSchService jschService= BaseCorePlugin.getInstance().getJSchService();
			if (session == null) {
				final IJSchLocation location= jschService.getLocation(username, host, port);
				session= jschService.createSession(location, null);
			}
			if (!session.isConnected()) {
				jschService.connect(session, SSH_TIMEOUT, new SubProgressMonitor(monitor, 1));
			}
			this.fPool.put(key, session);
			return session;
		}
		catch (final JSchException e) {
			// create new session, if existing session is broken
			if ("Packet corrupt".equals(e.getMessage()) && this.fPool.values().remove(session)) { //$NON-NLS-1$
				return getSshSession(username, host, port, monitor);
			}
			
			throw new CoreException(new Status(IStatus.ERROR, StatetCore.BUNDLE_ID, "Failed to create SSH connection", e));
		}
	}
	
	@Override
	public void dispose() {
		final Collection<Session> sessions= this.fPool.values();
		for (final Session session : sessions) {
			session.disconnect();
		}
		this.fPool= null;
	}
	
}