/*
 * 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.transport.sshd;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import java.io.File;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.file.Files;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import org.apache.sshd.client.config.hosts.KnownHostEntry;
import org.apache.sshd.server.ServerFactoryManager;
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.TransportException;
import org.eclipse.jgit.junit.ssh.SshTestBase;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.transport.SshSessionFactory;
import org.eclipse.jgit.util.FS;
import org.junit.Test;
import org.junit.experimental.theories.Theories;
import org.junit.runner.RunWith;

@RunWith(Theories.class)
public class ApacheSshTest extends SshTestBase {

	@Override
	protected SshSessionFactory createSessionFactory() {
		SshdSessionFactory result = new SshdSessionFactory(new JGitKeyCache(),
				null);
		// The home directory is mocked at this point!
		result.setHomeDirectory(FS.DETECTED.userHome());
		result.setSshDirectory(sshDir);
		return result;
	}

	@Override
	protected void installConfig(String... config) {
		File configFile = new File(sshDir, Constants.CONFIG);
		if (config != null) {
			try {
				Files.write(configFile.toPath(), Arrays.asList(config));
			} catch (IOException e) {
				throw new UncheckedIOException(e);
			}
		}
	}

	@Test
	public void testEd25519HostKey() throws Exception {
		// Using ed25519 user identities is tested in the super class in
		// testSshKeys().
		File newHostKey = new File(getTemporaryDirectory(), "newhostkey");
		copyTestResource("id_ed25519", newHostKey);
		server.addHostKey(newHostKey.toPath(), true);
		File newHostKeyPub = new File(getTemporaryDirectory(),
				"newhostkey.pub");
		copyTestResource("id_ed25519.pub", newHostKeyPub);
		createKnownHostsFile(knownHosts, "localhost", testPort, newHostKeyPub);
		cloneWith("ssh://git/doesntmatter", defaultCloneDir, null, //
				"Host git", //
				"HostName localhost", //
				"Port " + testPort, //
				"User " + TEST_USER, //
				"IdentityFile " + privateKey1.getAbsolutePath());
	}

	@Test
	public void testHashedKnownHosts() throws Exception {
		assertTrue("Failed to delete known_hosts", knownHosts.delete());
		// The provider will answer "yes" to all questions, so we should be able
		// to connect and end up with a new known_hosts file with the host key.
		TestCredentialsProvider provider = new TestCredentialsProvider();
		cloneWith("ssh://localhost/doesntmatter", defaultCloneDir, provider, //
				"HashKnownHosts yes", //
				"Host localhost", //
				"HostName localhost", //
				"Port " + testPort, //
				"User " + TEST_USER, //
				"IdentityFile " + privateKey1.getAbsolutePath());
		List<LogEntry> messages = provider.getLog();
		assertFalse("Expected user interaction", messages.isEmpty());
		assertEquals(
				"Expected to be asked about the key, and the file creation", 2,
				messages.size());
		assertTrue("~/.ssh/known_hosts should exist now", knownHosts.exists());
		// Let's clone again without provider. If it works, the server host key
		// was written correctly.
		File clonedAgain = new File(getTemporaryDirectory(), "cloned2");
		cloneWith("ssh://localhost/doesntmatter", clonedAgain, null, //
				"Host localhost", //
				"HostName localhost", //
				"Port " + testPort, //
				"User " + TEST_USER, //
				"IdentityFile " + privateKey1.getAbsolutePath());
		// Check that the first line contains neither "localhost" nor
		// "127.0.0.1", but does contain the expected hash.
		List<String> lines = Files.readAllLines(knownHosts.toPath()).stream()
				.filter(s -> s != null && s.length() >= 1 && s.charAt(0) != '#'
						&& !s.trim().isEmpty())
				.collect(Collectors.toList());
		assertEquals("Unexpected number of known_hosts lines", 1, lines.size());
		String line = lines.get(0);
		assertFalse("Found host in line", line.contains("localhost"));
		assertFalse("Found IP in line", line.contains("127.0.0.1"));
		assertTrue("Hash not found", line.contains("|"));
		KnownHostEntry entry = KnownHostEntry.parseKnownHostEntry(line);
		assertTrue("Hash doesn't match localhost",
				entry.isHostMatch("localhost", testPort)
						|| entry.isHostMatch("127.0.0.1", testPort));
	}

	@Test
	public void testPreamble() throws Exception {
		// Test that the client can deal with strange lines being sent before
		// the server identification string.
		StringBuilder b = new StringBuilder();
		for (int i = 0; i < 257; i++) {
			b.append('a');
		}
		server.setPreamble("A line with a \000 NUL",
				"A long line: " + b.toString());
		cloneWith(
				"ssh://" + TEST_USER + "@localhost:" + testPort
						+ "/doesntmatter",
				defaultCloneDir, null,
				"IdentityFile " + privateKey1.getAbsolutePath());
	}

	@Test
	public void testLongPreamble() throws Exception {
		// Test that the client can deal with a long (about 60k) preamble.
		StringBuilder b = new StringBuilder();
		for (int i = 0; i < 1024; i++) {
			b.append('a');
		}
		String line = b.toString();
		String[] lines = new String[60];
		for (int i = 0; i < lines.length; i++) {
			lines[i] = line;
		}
		server.setPreamble(lines);
		cloneWith(
				"ssh://" + TEST_USER + "@localhost:" + testPort
						+ "/doesntmatter",
				defaultCloneDir, null,
				"IdentityFile " + privateKey1.getAbsolutePath());
	}

	@Test (expected = TransportException.class)
	public void testHugePreamble() throws Exception {
		// Test that the connection fails when the preamble is longer than 64k.
		StringBuilder b = new StringBuilder();
		for (int i = 0; i < 1024; i++) {
			b.append('a');
		}
		String line = b.toString();
		String[] lines = new String[70];
		for (int i = 0; i < lines.length; i++) {
			lines[i] = line;
		}
		server.setPreamble(lines);
		cloneWith(
				"ssh://" + TEST_USER + "@localhost:" + testPort
						+ "/doesntmatter",
				defaultCloneDir, null,
				"IdentityFile " + privateKey1.getAbsolutePath());
	}

	/**
	 * Test for SSHD-1028. If the server doesn't close sessions, the second
	 * fetch will fail. Occurs on sshd 2.5.[01].
	 *
	 * @throws Exception
	 *             on errors
	 * @see <a href=
	 *      "https://issues.apache.org/jira/projects/SSHD/issues/SSHD-1028">SSHD-1028</a>
	 */
	@Test
	public void testCloneAndFetchWithSessionLimit() throws Exception {
		server.getProperties().put(ServerFactoryManager.MAX_CONCURRENT_SESSIONS,
				Integer.valueOf(2));
		File localClone = cloneWith("ssh://localhost/doesntmatter",
				defaultCloneDir, null, //
				"Host localhost", //
				"HostName localhost", //
				"Port " + testPort, //
				"User " + TEST_USER, //
				"IdentityFile " + privateKey1.getAbsolutePath());
		// Fetch a couple of times
		try (Git git = Git.open(localClone)) {
			git.fetch().call();
			git.fetch().call();
		}
	}
}