/*
    * Copyright (C) 2008, Google Inc. 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.pgm;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.text.MessageFormat;
  import java.util.jar.JarFile;
  import java.util.jar.Manifest;
  
  import org.eclipse.jgit.pgm.internal.CLIText;
  
  @Command(common = true, usage = "usage_DisplayTheVersionOfJgit")
  class Version extends TextBuiltin {
  	/** {@inheritDoc} */
  	@Override
  	protected void run() {
  		// read the Implementation-Version from Manifest
  		String version = getImplementationVersion();
  
  		// if Implementation-Version is not available then try reading
  		// Bundle-Version
  		if (version == null) {
  			version = getBundleVersion();
  		}
  
  		// if both Implementation-Version and Bundle-Version are not available
  		// then throw an exception
  		if (version == null) {
  			throw die(CLIText.get().cannotReadPackageInformation);
  		}
  
  		try {
  			outw.println(
  					MessageFormat.format(CLIText.get().jgitVersion, version));
  		} catch (IOException e) {
  			throw die(e.getMessage(), e);
  		}
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	protected final boolean requiresRepository() {
  		return false;
  	}
  
  	private String getImplementationVersion() {
  		Package pkg = getClass().getPackage();
  		return (pkg == null) ? null : pkg.getImplementationVersion();
  	}
  
  	private String getBundleVersion() {
  		ClassLoader cl = getClass().getClassLoader();
  		if (cl instanceof URLClassLoader) {
  			URL url = ((URLClassLoader) cl).findResource(JarFile.MANIFEST_NAME);
  			if (url != null)
  				return getBundleVersion(url);
  		}
  		return null;
  	}
  
  	private static String getBundleVersion(URL url) {
  		try (InputStream is = url.openStream()) {
  			Manifest manifest = new Manifest(is);
  			return manifest.getMainAttributes().getValue("Bundle-Version"); //$NON-NLS-1$
  		} catch (IOException e) {
  			// do nothing - will return null
  		}
  		return null;
  	}
  }