/*
 * Copyright (C) 2006, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> 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 static java.nio.charset.StandardCharsets.UTF_8;

import java.io.File;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.lang.reflect.InvocationTargetException;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;

import org.eclipse.jgit.awtui.AwtAuthenticator;
import org.eclipse.jgit.awtui.AwtCredentialsProvider;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.lfs.BuiltinLFS;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.RepositoryBuilder;
import org.eclipse.jgit.pgm.internal.CLIText;
import org.eclipse.jgit.pgm.opt.CmdLineParser;
import org.eclipse.jgit.pgm.opt.SubcommandHandler;
import org.eclipse.jgit.transport.HttpTransport;
import org.eclipse.jgit.transport.http.apache.HttpClientConnectionFactory;
import org.eclipse.jgit.util.CachedAuthenticator;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.Option;
import org.kohsuke.args4j.OptionHandlerFilter;

/**
 * Command line entry point.
 */
public class Main {
	@Option(name = "--help", usage = "usage_displayThisHelpText", aliases = { "-h" })
	private boolean help;

	@Option(name = "--version", usage = "usage_displayVersion")
	private boolean version;

	@Option(name = "--show-stack-trace", usage = "usage_displayThejavaStackTraceOnExceptions")
	private boolean showStackTrace;

	@Option(name = "--git-dir", metaVar = "metaVar_gitDir", usage = "usage_setTheGitRepositoryToOperateOn")
	private String gitdir;

	@Argument(index = 0, metaVar = "metaVar_command", required = true, handler = SubcommandHandler.class)
	private TextBuiltin subcommand;

	@Argument(index = 1, metaVar = "metaVar_arg")
	private List<String> arguments = new ArrayList<>();

	PrintWriter writer;

	private ExecutorService gcExecutor;

	/**
	 * <p>Constructor for Main.</p>
	 */
	public Main() {
		HttpTransport.setConnectionFactory(new HttpClientConnectionFactory());
		BuiltinLFS.register();
		gcExecutor = Executors.newSingleThreadExecutor(new ThreadFactory() {
			private final ThreadFactory baseFactory = Executors
					.defaultThreadFactory();

			@Override
			public Thread newThread(Runnable taskBody) {
				Thread thr = baseFactory.newThread(taskBody);
				thr.setName("JGit-autoGc"); //$NON-NLS-1$
				return thr;
			}
		});
	}

	/**
	 * Execute the command line.
	 *
	 * @param argv
	 *            arguments.
	 * @throws java.lang.Exception
	 *             if an error occurred
	 */
	public static void main(String[] argv) throws Exception {
		// make sure built-in filters are registered
		BuiltinLFS.register();

		new Main().run(argv);
	}

	/**
	 * Parse the command line and execute the requested action.
	 *
	 * Subclasses should allocate themselves and then invoke this method:
	 *
	 * <pre>
	 * class ExtMain {
	 * 	public static void main(String[] argv) {
	 * 		new ExtMain().run(argv);
	 * 	}
	 * }
	 * </pre>
	 *
	 * @param argv
	 *            arguments.
	 * @throws java.lang.Exception
	 *             if an error occurred
	 */
	protected void run(String[] argv) throws Exception {
		writer = createErrorWriter();
		try {
			if (!installConsole()) {
				AwtAuthenticator.install();
				AwtCredentialsProvider.install();
			}
			configureHttpProxy();
			execute(argv);
		} catch (Die err) {
			if (err.isAborted()) {
				exit(1, err);
			}
			writer.println(CLIText.fatalError(err.getMessage()));
			if (showStackTrace) {
				err.printStackTrace(writer);
			}
			exit(128, err);
		} catch (Exception err) {
			// Try to detect errno == EPIPE and exit normally if that happens
			// There may be issues with operating system versions and locale,
			// but we can probably assume that these messages will not be thrown
			// under other circumstances.
			if (err.getClass() == IOException.class) {
				// Linux, OS X
				if (err.getMessage().equals("Broken pipe")) { //$NON-NLS-1$
					exit(0, err);
				}
				// Windows
				if (err.getMessage().equals("The pipe is being closed")) { //$NON-NLS-1$
					exit(0, err);
				}
			}
			if (!showStackTrace && err.getCause() != null
					&& err instanceof TransportException) {
				writer.println(CLIText.fatalError(err.getCause().getMessage()));
			}

			if (err.getClass().getName().startsWith("org.eclipse.jgit.errors.")) { //$NON-NLS-1$
				writer.println(CLIText.fatalError(err.getMessage()));
				if (showStackTrace) {
					err.printStackTrace();
				}
				exit(128, err);
			}
			err.printStackTrace();
			exit(1, err);
		}
		if (System.out.checkError()) {
			writer.println(CLIText.get().unknownIoErrorStdout);
			exit(1, null);
		}
		if (writer.checkError()) {
			// No idea how to present an error here, most likely disk full or
			// broken pipe
			exit(1, null);
		}
		gcExecutor.shutdown();
		gcExecutor.awaitTermination(10, TimeUnit.MINUTES);
	}

	PrintWriter createErrorWriter() {
		return new PrintWriter(new OutputStreamWriter(System.err, UTF_8));
	}

	private void execute(String[] argv) throws Exception {
		final CmdLineParser clp = new SubcommandLineParser(this);

		try {
			clp.parseArgument(argv);
		} catch (CmdLineException err) {
			if (argv.length > 0 && !help && !version) {
				writer.println(CLIText.fatalError(err.getMessage()));
				writer.flush();
				exit(1, err);
			}
		}

		if (argv.length == 0 || help) {
			final String ex = clp.printExample(OptionHandlerFilter.ALL,
					CLIText.get().resourceBundle());
			writer.println("jgit" + ex + " command [ARG ...]"); //$NON-NLS-1$ //$NON-NLS-2$
			if (help) {
				writer.println();
				clp.printUsage(writer, CLIText.get().resourceBundle());
				writer.println();
			} else if (subcommand == null) {
				writer.println();
				writer.println(CLIText.get().mostCommonlyUsedCommandsAre);
				final CommandRef[] common = CommandCatalog.common();
				int width = 0;
				for (CommandRef c : common) {
					width = Math.max(width, c.getName().length());
				}
				width += 2;

				for (CommandRef c : common) {
					writer.print(' ');
					writer.print(c.getName());
					for (int i = c.getName().length(); i < width; i++) {
						writer.print(' ');
					}
					writer.print(CLIText.get().resourceBundle().getString(c.getUsage()));
					writer.println();
				}
				writer.println();
			}
			writer.flush();
			exit(1, null);
		}

		if (version) {
			String cmdId = Version.class.getSimpleName()
					.toLowerCase(Locale.ROOT);
			subcommand = CommandCatalog.get(cmdId).create();
		}

		final TextBuiltin cmd = subcommand;
		init(cmd);
		try {
			cmd.execute(arguments.toArray(new String[0]));
		} finally {
			if (cmd.outw != null) {
				cmd.outw.flush();
			}
			if (cmd.errw != null) {
				cmd.errw.flush();
			}
		}
	}

	void init(TextBuiltin cmd) throws IOException {
		if (cmd.requiresRepository()) {
			cmd.init(openGitDir(gitdir), null);
		} else {
			cmd.init(null, gitdir);
		}
	}

	/**
	 * @param status
	 *            exit status code, nonzero value indicates an error
	 * @param t
	 *            can be {@code null}
	 * @throws Exception
	 *             if an IO error occurred
	 */
	void exit(int status, Exception t) throws Exception {
		writer.flush();
		System.exit(status);
	}

	/**
	 * Evaluate the {@code --git-dir} option and open the repository.
	 *
	 * @param aGitdir
	 *            the {@code --git-dir} option given on the command line. May be
	 *            null if it was not supplied.
	 * @return the repository to operate on.
	 * @throws java.io.IOException
	 *             the repository cannot be opened.
	 */
	protected Repository openGitDir(String aGitdir) throws IOException {
		RepositoryBuilder rb = new RepositoryBuilder() //
				.setGitDir(aGitdir != null ? new File(aGitdir) : null) //
				.readEnvironment() //
				.findGitDir();
		if (rb.getGitDir() == null)
			throw new Die(CLIText.get().cantFindGitDirectory);
		return rb.build();
	}

	private static boolean installConsole() {
		try {
			install("org.eclipse.jgit.console.ConsoleAuthenticator"); //$NON-NLS-1$
			install("org.eclipse.jgit.console.ConsoleCredentialsProvider"); //$NON-NLS-1$
			return true;
		} catch (ClassNotFoundException | NoClassDefFoundError
				| UnsupportedClassVersionError e) {
			return false;
		} catch (IllegalArgumentException | SecurityException
				| IllegalAccessException | InvocationTargetException
				| NoSuchMethodException e) {
			throw new RuntimeException(CLIText.get().cannotSetupConsole, e);
		}
	}

	private static void install(String name)
			throws IllegalAccessException, InvocationTargetException,
			NoSuchMethodException, ClassNotFoundException {
		try {
			Class.forName(name).getMethod("install").invoke(null); //$NON-NLS-1$
		} catch (InvocationTargetException e) {
			if (e.getCause() instanceof RuntimeException)
				throw (RuntimeException) e.getCause();
			if (e.getCause() instanceof Error)
				throw (Error) e.getCause();
			throw e;
		}
	}

	/**
	 * Configure the JRE's standard HTTP based on <code>http_proxy</code>.
	 * <p>
	 * The popular libcurl library honors the <code>http_proxy</code>,
	 * <code>https_proxy</code> environment variables as a means of specifying
	 * an HTTP/S proxy for requests made behind a firewall. This is not natively
	 * recognized by the JRE, so this method can be used by command line
	 * utilities to configure the JRE before the first request is sent. The
	 * information found in the environment variables is copied to the
	 * associated system properties. This is not done when the system properties
	 * are already set. The default way of telling java programs about proxies
	 * (the system properties) takes precedence over environment variables.
	 *
	 * @throws MalformedURLException
	 *             the value in <code>http_proxy</code> or
	 *             <code>https_proxy</code> is unsupportable.
	 */
	static void configureHttpProxy() throws MalformedURLException {
		for (String protocol : new String[] { "http", "https" }) { //$NON-NLS-1$ //$NON-NLS-2$
			if (System.getProperty(protocol + ".proxyHost") != null) { //$NON-NLS-1$
				continue;
			}
			String s = System.getenv(protocol + "_proxy"); //$NON-NLS-1$
			if (s == null && protocol.equals("https")) { //$NON-NLS-1$
				s = System.getenv("HTTPS_PROXY"); //$NON-NLS-1$
			}
			if (s == null || s.isEmpty()) {
				continue;
			}

			URL u = new URL(!s.contains("://") ? protocol + "://" + s : s); //$NON-NLS-1$ //$NON-NLS-2$
			if (!u.getProtocol().startsWith("http")) //$NON-NLS-1$
				throw new MalformedURLException(MessageFormat.format(
						CLIText.get().invalidHttpProxyOnlyHttpSupported, s));

			final String proxyHost = u.getHost();
			final int proxyPort = u.getPort();

			System.setProperty(protocol + ".proxyHost", proxyHost); //$NON-NLS-1$
			if (proxyPort > 0)
				System.setProperty(protocol + ".proxyPort", //$NON-NLS-1$
						String.valueOf(proxyPort));

			final String userpass = u.getUserInfo();
			if (userpass != null && userpass.contains(":")) { //$NON-NLS-1$
				final int c = userpass.indexOf(':');
				final String user = userpass.substring(0, c);
				final String pass = userpass.substring(c + 1);
				CachedAuthenticator.add(
						new CachedAuthenticator.CachedAuthentication(proxyHost,
								proxyPort, user, pass));
			}
		}
	}

	/**
	 * Parser for subcommands which doesn't stop parsing on help options and so
	 * proceeds all specified options
	 */
	static class SubcommandLineParser extends CmdLineParser {
		public SubcommandLineParser(Object bean) {
			super(bean);
		}

		@Override
		protected boolean containsHelp(String... args) {
			return false;
		}
	}
}