/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.maven.scm.provider.git.command.checkout;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.Writer;
  import java.nio.file.FileSystem;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.attribute.PosixFilePermissions;
  import java.security.GeneralSecurityException;
  import java.security.KeyPair;
  import java.security.PublicKey;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.maven.scm.provider.ScmProviderRepositoryWithHost;
  import org.apache.maven.scm.provider.git.GitScmTestUtils;
  import org.apache.maven.scm.repository.ScmRepository;
  import org.apache.maven.scm.tck.command.checkout.CheckOutCommandTckTest;
  import org.apache.sshd.common.config.keys.KeyUtils;
  import org.apache.sshd.common.config.keys.writer.openssh.OpenSSHKeyEncryptionContext;
  import org.apache.sshd.common.config.keys.writer.openssh.OpenSSHKeyPairResourceWriter;
  import org.apache.sshd.git.GitLocationResolver;
  import org.apache.sshd.git.pack.GitPackCommandFactory;
  import org.apache.sshd.server.SshServer;
  import org.apache.sshd.server.auth.pubkey.KeySetPublickeyAuthenticator;
  import org.apache.sshd.server.auth.pubkey.PublickeyAuthenticator;
  import org.apache.sshd.server.session.ServerSession;
  import org.apache.sshd.util.test.CommonTestSupportUtils;
  import org.apache.sshd.util.test.CoreTestSupportUtils;
  import org.bouncycastle.openssl.PKCS8Generator;
  import org.bouncycastle.openssl.jcajce.JcaPEMWriter;
  import org.bouncycastle.openssl.jcajce.JcaPKCS8Generator;
  import org.bouncycastle.util.io.pem.PemObject;
  import org.junit.Assume;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.rules.TemporaryFolder;
  
  /**
   *
   */
  public abstract class GitSshCheckOutCommandTckTest extends CheckOutCommandTckTest {
      protected final SshServer sshServer;
      protected final KeyPair keyPair;
      protected final List<PublicKey> acceptedPublicKeys;
  
      @Rule
      public TemporaryFolder tmpDirectory = new TemporaryFolder();
  
      protected GitSshCheckOutCommandTckTest() throws GeneralSecurityException {
          sshServer = CoreTestSupportUtils.setupTestServer(getClass());
          keyPair = CommonTestSupportUtils.generateKeyPair(KeyUtils.RSA_ALGORITHM, 2048);
          acceptedPublicKeys = new ArrayList<>();
          acceptedPublicKeys.add(keyPair.getPublic());
          PublickeyAuthenticator authenticator = new KeySetPublickeyAuthenticator("onlykey", acceptedPublicKeys);
          sshServer.setPublickeyAuthenticator(authenticator);
      }
  
      void writePrivateKeyAsPkcs8(Path file, String passphrase) throws IOException, GeneralSecurityException {
          // encryption only optional
          if (passphrase != null) {
              // encryption with format outlined in https://dnaeon.github.io/openssh-private-key-binary-format/
              OpenSSHKeyPairResourceWriter writer = new OpenSSHKeyPairResourceWriter();
              OpenSSHKeyEncryptionContext context = new OpenSSHKeyEncryptionContext();
              context.setCipherType("192");
              context.setPassword(passphrase);
              try (OutputStream output = Files.newOutputStream(file)) {
                  writer.writePrivateKey(keyPair, "comment", context, output);
              }
          } else {
              // wrap unencrypted private key as regular PKCS8 private key
              PKCS8Generator pkcs8Generator = new JcaPKCS8Generator(keyPair.getPrivate(), null);
              PemObject pemObject = pkcs8Generator.generate();
  
              try (Writer writer = Files.newBufferedWriter(file);
                      JcaPEMWriter pw = new JcaPEMWriter(writer)) {
                  pw.writeObject(pemObject);
              }
          }
  
         if (file.getFileSystem().supportedFileAttributeViews().contains("posix")) {
             // must only be readable/writeable by me
             Files.setPosixFilePermissions(file, PosixFilePermissions.fromString("rwx------"));
         }
     }
 
     protected abstract String getScmProvider();
 
     /** {@inheritDoc} */
     public String getScmUrl() throws Exception {
         return "scm:" + getScmProvider() + ":ssh://localhost:" + sshServer.getPort() + "/repository";
     }
 
     public void configureCredentials(ScmRepository repository, String passphrase) throws Exception {
         ScmProviderRepositoryWithHost providerRepository =
                 ScmProviderRepositoryWithHost.class.cast(repository.getProviderRepository());
         // store as file
         Path privateKeyFile = tmpDirectory.newFile().toPath();
         writePrivateKeyAsPkcs8(privateKeyFile, passphrase);
         providerRepository.setPrivateKey(privateKeyFile.toString());
         providerRepository.setPassphrase(passphrase); // may be null
     }
 
     /** {@inheritDoc} */
     public void initRepo() throws Exception {
         GitScmTestUtils.initRepo("src/test/resources/repository/", getRepositoryRoot(), getWorkingDirectory());
 
         GitLocationResolver gitLocationResolver = new GitLocationResolver() {
             @Override
             public Path resolveRootDirectory(String command, String[] args, ServerSession session, FileSystem fs)
                     throws IOException {
                 return getRepositoryRoot().getParentFile().toPath();
             }
         };
         sshServer.setCommandFactory(new GitPackCommandFactory(gitLocationResolver));
         sshServer.start();
 
         // as checkout also already happens in setup() make sure to configure credentials here as well
         configureCredentials(getScmRepository(), null);
     }
 
     @Override
     public void removeRepo() throws Exception {
         sshServer.stop();
         super.removeRepo();
     }
 
     @Override
     @Test
     public void testCheckOutCommandTest() throws Exception {
         configureCredentials(getScmRepository(), null);
         super.testCheckOutCommandTest();
     }
 
     @Test
     public void testCheckOutCommandWithPassphraseTest() throws Exception {
         // TODO: currently no easy way to pass passphrase in gitexe
         Assume.assumeTrue(
                 "Ignore test with passphrase for provider " + getScmProvider(), "jgit".equals(getScmProvider()));
         configureCredentials(getScmRepository(), "mySecret");
         super.testCheckOutCommandTest();
     }
 }