package net.trajano.wagon.git;
   
   import java.io.File;
   import java.io.IOException;
   import java.net.URI;
   import java.net.URISyntaxException;
   
   import net.trajano.wagon.git.internal.AbstractGitWagon;
   import net.trajano.wagon.git.internal.GitUri;
  
  import org.apache.maven.wagon.ResourceDoesNotExistException;
  import org.apache.maven.wagon.Wagon;
  import org.codehaus.plexus.component.annotations.Component;
  import org.eclipse.jgit.api.Git;
  import org.eclipse.jgit.api.errors.GitAPIException;
  
  /**
   * Git Wagon. Due to issues with the way maven-site-plugin is improperly sending
   * requests that assume the target repository is a file system, the handling of
   * git URIs fails. This performs an inefficient, but working method of creating
   * a clone per request, but only once per Git repository.
   */
  @Component(role = Wagon.class, hint = "git", instantiationStrategy = "per-lookup")
  public class GitWagon extends AbstractGitWagon {
      /**
       * Constructs the object from a URI string that contains "git:" schema.
       * {@inheritDoc}
       */
      @Override
      public GitUri buildGitUri(final URI gitUri) {
          final String branchName = gitUri.getQuery();
          final String asciiUriString = gitUri.toASCIIString();
          final String gitRepositoryUri = asciiUriString.substring(0,
                  asciiUriString.indexOf('?'));
          final String resource = gitUri.getFragment();
          return new GitUri(gitRepositoryUri, branchName, resource);
      }
  
      @Override
      public File getFileForResource(final String resourceName)
              throws GitAPIException, IOException, URISyntaxException {
          // /foo/bar/foo.git + ../bar.git == /foo/bar/bar.git + /
          // /foo/bar/foo.git + ../bar.git/abc == /foo/bar/bar.git + /abc
          final GitUri resolved = getGitUri().resolve(resourceName);
          Git resourceGit;
          try {
              resourceGit = getGit(resolved.getGitRepositoryUri());
          } catch (final ResourceDoesNotExistException e) {
              return null;
          }
  
          final File workTree = resourceGit.getRepository().getWorkTree();
          final File resolvedFile = new File(workTree, resolved.getResource());
          if (!resolvedFile.getCanonicalPath().startsWith(
                  workTree.getCanonicalPath())) {
              throw new IOException(String.format(
                      "The resolved file '%s' is not in work tree '%s'",
                      resolvedFile, workTree));
          }
          return resolvedFile;
      }
  }