/*
    * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  package org.eclipse.jgit.internal.transport.sshd;
  
  import static org.apache.sshd.core.CoreModuleProperties.PASSWORD_PROMPTS;
  
  import org.apache.sshd.client.auth.keyboard.UserInteraction;
  import org.apache.sshd.client.auth.password.UserAuthPassword;
  import org.apache.sshd.client.session.ClientSession;
  
  /**
   * A password authentication handler that uses the {@link JGitUserInteraction}
   * to ask the user for the password. It also respects the
   * {@code NumberOfPasswordPrompts} ssh config.
   */
  public class JGitPasswordAuthentication extends UserAuthPassword {
  
  	private int maxAttempts;
  
  	private int attempts;
  
  	@Override
  	public void init(ClientSession session, String service) throws Exception {
  		super.init(session, service);
  		maxAttempts = Math.max(1,
  				PASSWORD_PROMPTS.getRequired(session).intValue());
  		attempts = 0;
  	}
  
  	@Override
  	protected boolean sendAuthDataRequest(ClientSession session, String service)
  			throws Exception {
  		if (++attempts > maxAttempts) {
  			return false;
  		}
  		UserInteraction interaction = session.getUserInteraction();
  		if (!interaction.isInteractionAllowed(session)) {
  			return false;
  		}
  		String password = getPassword(session, interaction);
  		if (password == null) {
  			throw new AuthenticationCanceledException();
  		}
  		// sendPassword takes a buffer as first argument, but actually doesn't
  		// use it and creates its own buffer...
  		sendPassword(null, session, password, password);
  		return true;
  	}
  
  	private String getPassword(ClientSession session,
  			UserInteraction interaction) {
  		String[] results = interaction.interactive(session, null, null, "", //$NON-NLS-1$
  				new String[] { SshdText.get().passwordPrompt },
  				new boolean[] { false });
  		return (results == null || results.length == 0) ? null : results[0];
  	}
  }