/*
    * 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 java.io.IOException;
  import java.net.URISyntaxException;
  import java.security.GeneralSecurityException;
  import java.util.Arrays;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.sshd.common.NamedResource;
  import org.apache.sshd.common.session.SessionContext;
  import org.eclipse.jgit.annotations.NonNull;
  import org.eclipse.jgit.transport.CredentialsProvider;
  import org.eclipse.jgit.transport.URIish;
  import org.eclipse.jgit.transport.sshd.KeyPasswordProvider;
  
  /**
   * A bridge from sshd's {@link RepeatingFilePasswordProvider} to our
   * {@link KeyPasswordProvider} API.
   */
  public class PasswordProviderWrapper implements RepeatingFilePasswordProvider {
  
  	private final KeyPasswordProvider delegate;
  
  	private Map<String, AtomicInteger> counts = new ConcurrentHashMap<>();
  
  	/**
  	 * @param delegate
  	 */
  	public PasswordProviderWrapper(@NonNull KeyPasswordProvider delegate) {
  		this.delegate = delegate;
  	}
  
  	@Override
  	public void setAttempts(int numberOfPasswordPrompts) {
  		delegate.setAttempts(numberOfPasswordPrompts);
  	}
  
  	@Override
  	public int getAttempts() {
  		return delegate.getAttempts();
  	}
  
  	@Override
  	public String getPassword(SessionContext session, NamedResource resource,
  			int attemptIndex) throws IOException {
  		String key = resource.getName();
  		int attempt = counts
  				.computeIfAbsent(key, k -> new AtomicInteger()).get();
  		char[] passphrase = delegate.getPassphrase(toUri(key), attempt);
  		if (passphrase == null) {
  			return null;
  		}
  		try {
  			return new String(passphrase);
  		} finally {
  			Arrays.fill(passphrase, '\000');
  		}
  	}
  
  	@Override
  	public ResourceDecodeResult handleDecodeAttemptResult(
  			SessionContext session, NamedResource resource, int retryIndex,
  			String password, Exception err)
  			throws IOException, GeneralSecurityException {
  		String key = resource.getName();
  		AtomicInteger count = counts.get(key);
  		int numberOfAttempts = count == null ? 0 : count.incrementAndGet();
  		ResourceDecodeResult result = null;
  		try {
  			if (delegate.keyLoaded(toUri(key), numberOfAttempts, err)) {
  				result = ResourceDecodeResult.RETRY;
  			} else {
  				result = ResourceDecodeResult.TERMINATE;
  			}
  		} finally {
  			if (result != ResourceDecodeResult.RETRY) {
  				counts.remove(key);
  			}
  		}
  		return result;
  	}
  
  	/**
  	 * Creates a {@link URIish} from a given string. The
  	 * {@link CredentialsProvider} uses uris as resource identifications.
  	 *
  	 * @param resourceKey
  	 *            to convert
 	 * @return the uri
 	 */
 	private URIish toUri(String resourceKey) {
 		try {
 			return new URIish(resourceKey);
 		} catch (URISyntaxException e) {
 			return new URIish().setPath(resourceKey); // Doesn't check!!
 		}
 	}
 
 }