/*
    * Copyright (C) 2009-2010, Google Inc.
    * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
    * Copyright (C) 2007, 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.junit;
  
  import static java.nio.charset.StandardCharsets.UTF_8;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.fail;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.PrintStream;
  import java.time.Instant;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeSet;
  
  import org.eclipse.jgit.dircache.DirCache;
  import org.eclipse.jgit.dircache.DirCacheEntry;
  import org.eclipse.jgit.internal.storage.file.FileRepository;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.PersonIdent;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.lib.RepositoryCache;
  import org.eclipse.jgit.storage.file.FileBasedConfig;
  import org.eclipse.jgit.storage.file.WindowCacheConfig;
  import org.eclipse.jgit.util.FS;
  import org.eclipse.jgit.util.FileUtils;
  import org.eclipse.jgit.util.SystemReader;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Rule;
  import org.junit.rules.TestName;
  
  /**
   * JUnit TestCase with specialized support for temporary local repository.
   * <p>
   * A temporary directory is created for each test, allowing each test to use a
   * fresh environment. The temporary directory is cleaned up after the test ends.
   * <p>
   * Callers should not use {@link org.eclipse.jgit.lib.RepositoryCache} from
   * within these tests as it may wedge file descriptors open past the end of the
   * test.
   * <p>
   * A system property {@code jgit.junit.usemmap} defines whether memory mapping
   * is used. Memory mapping has an effect on the file system, in that memory
   * mapped files in Java cannot be deleted as long as the mapped arrays have not
   * been reclaimed by the garbage collector. The programmer cannot control this
   * with precision, so temporary files may hang around longer than desired during
   * a test, or tests may fail altogether if there is insufficient file
   * descriptors or address space for the test process.
   */
  public abstract class LocalDiskRepositoryTestCase {
  	private static final boolean useMMAP = "true".equals(System
  			.getProperty("jgit.junit.usemmap"));
  
  	/** A fake (but stable) identity for author fields in the test. */
  	protected PersonIdent author;
  
  	/** A fake (but stable) identity for committer fields in the test. */
  	protected PersonIdent committer;
  
  	/**
  	 * A {@link SystemReader} used to coordinate time, envars, etc.
  	 * @since 4.2
  	 */
  	protected MockSystemReader mockSystemReader;
  
  	private final Set<Repository> toClose = new HashSet<>();
  	private File tmp;
  
  	/**
  	 * The current test name.
  	 */
  	@Rule
  	public TestName currentTest = new TestName();
  
  	private String getTestName() {
  		String name = currentTest.getMethodName();
  		name = name.replaceAll("[^a-zA-Z0-9]", "_");
  		name = name.replaceAll("__+", "_");
  		if (name.startsWith("_")) {
  			name = name.substring(1);
 		}
 		return name;
 	}
 
 	/**
 	 * Setup test
 	 *
 	 * @throws Exception
 	 */
 	@Before
 	public void setUp() throws Exception {
 		tmp = File.createTempFile("jgit_" + getTestName() + '_', "_tmp");
 		CleanupThread.deleteOnShutdown(tmp);
 		if (!tmp.delete() || !tmp.mkdir()) {
 			throw new IOException("Cannot create " + tmp);
 		}
 		mockSystemReader = new MockSystemReader();
 		SystemReader.setInstance(mockSystemReader);
 
 		// Measure timer resolution before the test to avoid time critical tests
 		// are affected by time needed for measurement.
 		// The MockSystemReader must be configured first since we need to use
 		// the same one here
 		FS.getFileStoreAttributes(tmp.toPath().getParent());
 
 		FileBasedConfig jgitConfig = new FileBasedConfig(
 				new File(tmp, "jgitconfig"), FS.DETECTED);
 		FileBasedConfig systemConfig = new FileBasedConfig(jgitConfig,
 				new File(tmp, "systemgitconfig"), FS.DETECTED);
 		FileBasedConfig userConfig = new FileBasedConfig(systemConfig,
 				new File(tmp, "usergitconfig"), FS.DETECTED);
 		// We have to set autoDetach to false for tests, because tests expect to be able
 		// to clean up by recursively removing the repository, and background GC might be
 		// in the middle of writing or deleting files, which would disrupt this.
 		userConfig.setBoolean(ConfigConstants.CONFIG_GC_SECTION,
 				null, ConfigConstants.CONFIG_KEY_AUTODETACH, false);
 		userConfig.save();
 		mockSystemReader.setJGitConfig(jgitConfig);
 		mockSystemReader.setSystemGitConfig(systemConfig);
 		mockSystemReader.setUserGitConfig(userConfig);
 
 		ceilTestDirectories(getCeilings());
 
 		author = new PersonIdent("J. Author", "jauthor@example.com");
 		committer = new PersonIdent("J. Committer", "jcommitter@example.com");
 
 		final WindowCacheConfig c = new WindowCacheConfig();
 		c.setPackedGitLimit(128 * WindowCacheConfig.KB);
 		c.setPackedGitWindowSize(8 * WindowCacheConfig.KB);
 		c.setPackedGitMMAP(useMMAP);
 		c.setDeltaBaseCacheLimit(8 * WindowCacheConfig.KB);
 		c.install();
 	}
 
 	/**
 	 * Get temporary directory.
 	 *
 	 * @return the temporary directory
 	 */
 	protected File getTemporaryDirectory() {
 		return tmp.getAbsoluteFile();
 	}
 
 	/**
 	 * Get list of ceiling directories
 	 *
 	 * @return list of ceiling directories
 	 */
 	protected List<File> getCeilings() {
 		return Collections.singletonList(getTemporaryDirectory());
 	}
 
 	private void ceilTestDirectories(List<File> ceilings) {
 		mockSystemReader.setProperty(Constants.GIT_CEILING_DIRECTORIES_KEY, makePath(ceilings));
 	}
 
 	private static String makePath(List<?> objects) {
 		final StringBuilder stringBuilder = new StringBuilder();
 		for (Object object : objects) {
 			if (stringBuilder.length() > 0)
 				stringBuilder.append(File.pathSeparatorChar);
 			stringBuilder.append(object.toString());
 		}
 		return stringBuilder.toString();
 	}
 
 	/**
 	 * Tear down the test
 	 *
 	 * @throws Exception
 	 */
 	@After
 	public void tearDown() throws Exception {
 		RepositoryCache.clear();
 		for (Repository r : toClose)
 			r.close();
 		toClose.clear();
 
 		// Since memory mapping is controlled by the GC we need to
 		// tell it this is a good time to clean up and unlock
 		// memory mapped files.
 		//
 		if (useMMAP)
 			System.gc();
 		if (tmp != null)
 			recursiveDelete(tmp, false, true);
 		if (tmp != null && !tmp.exists())
 			CleanupThread.removed(tmp);
 
 		SystemReader.setInstance(null);
 	}
 
 	/**
 	 * Increment the {@link #author} and {@link #committer} times.
 	 */
 	protected void tick() {
 		mockSystemReader.tick(5 * 60);
 		final long now = mockSystemReader.getCurrentTime();
 		final int tz = mockSystemReader.getTimezone(now);
 
 		author = new PersonIdent(author, now, tz);
 		committer = new PersonIdent(committer, now, tz);
 	}
 
 	/**
 	 * Recursively delete a directory, failing the test if the delete fails.
 	 *
 	 * @param dir
 	 *            the recursively directory to delete, if present.
 	 */
 	protected void recursiveDelete(File dir) {
 		recursiveDelete(dir, false, true);
 	}
 
 	private static boolean recursiveDelete(final File dir,
 			boolean silent, boolean failOnError) {
 		assert !(silent && failOnError);
 		int options = FileUtils.RECURSIVE | FileUtils.RETRY
 				| FileUtils.SKIP_MISSING;
 		if (silent) {
 			options |= FileUtils.IGNORE_ERRORS;
 		}
 		try {
 			FileUtils.delete(dir, options);
 		} catch (IOException e) {
 			reportDeleteFailure(failOnError, dir, e);
 			return !failOnError;
 		}
 		return true;
 	}
 
 	private static void reportDeleteFailure(boolean failOnError, File f,
 			Exception cause) {
 		String severity = failOnError ? "ERROR" : "WARNING";
 		String msg = severity + ": Failed to delete " + f;
 		if (failOnError) {
 			fail(msg);
 		} else {
 			System.err.println(msg);
 		}
 		cause.printStackTrace(new PrintStream(System.err));
 	}
 
 	/** Constant <code>MOD_TIME=1</code> */
 	public static final int MOD_TIME = 1;
 
 	/** Constant <code>SMUDGE=2</code> */
 	public static final int SMUDGE = 2;
 
 	/** Constant <code>LENGTH=4</code> */
 	public static final int LENGTH = 4;
 
 	/** Constant <code>CONTENT_ID=8</code> */
 	public static final int CONTENT_ID = 8;
 
 	/** Constant <code>CONTENT=16</code> */
 	public static final int CONTENT = 16;
 
 	/** Constant <code>ASSUME_UNCHANGED=32</code> */
 	public static final int ASSUME_UNCHANGED = 32;
 
 	/**
 	 * Represent the state of the index in one String. This representation is
 	 * useful when writing tests which do assertions on the state of the index.
 	 * By default information about path, mode, stage (if different from 0) is
 	 * included. A bitmask controls which additional info about
 	 * modificationTimes, smudge state and length is included.
 	 * <p>
 	 * The format of the returned string is described with this BNF:
 	 *
 	 * <pre>
 	 * result = ( "[" path mode stage? time? smudge? length? sha1? content? "]" )* .
 	 * mode = ", mode:" number .
 	 * stage = ", stage:" number .
 	 * time = ", time:t" timestamp-index .
 	 * smudge = "" | ", smudged" .
 	 * length = ", length:" number .
 	 * sha1 = ", sha1:" hex-sha1 .
 	 * content = ", content:" blob-data .
 	 * </pre>
 	 *
 	 * 'stage' is only presented when the stage is different from 0. All
 	 * reported time stamps are mapped to strings like "t0", "t1", ... "tn". The
 	 * smallest reported time-stamp will be called "t0". This allows to write
 	 * assertions against the string although the concrete value of the time
 	 * stamps is unknown.
 	 *
 	 * @param repo
 	 *            the repository the index state should be determined for
 	 * @param includedOptions
 	 *            a bitmask constructed out of the constants {@link #MOD_TIME},
 	 *            {@link #SMUDGE}, {@link #LENGTH}, {@link #CONTENT_ID} and
 	 *            {@link #CONTENT} controlling which info is present in the
 	 *            resulting string.
 	 * @return a string encoding the index state
 	 * @throws IllegalStateException
 	 * @throws IOException
 	 */
 	public static String indexState(Repository repo, int includedOptions)
 			throws IllegalStateException, IOException {
 		DirCache dc = repo.readDirCache();
 		StringBuilder sb = new StringBuilder();
 		TreeSet<Instant> timeStamps = new TreeSet<>();
 
 		// iterate once over the dircache just to collect all time stamps
 		if (0 != (includedOptions & MOD_TIME)) {
 			for (int i = 0; i < dc.getEntryCount(); ++i) {
 				timeStamps.add(dc.getEntry(i).getLastModifiedInstant());
 			}
 		}
 
 		// iterate again, now produce the result string
 		for (int i=0; i<dc.getEntryCount(); ++i) {
 			DirCacheEntry entry = dc.getEntry(i);
 			sb.append("["+entry.getPathString()+", mode:" + entry.getFileMode());
 			int stage = entry.getStage();
 			if (stage != 0)
 				sb.append(", stage:" + stage);
 			if (0 != (includedOptions & MOD_TIME)) {
 				sb.append(", time:t"+
 						timeStamps.headSet(entry.getLastModifiedInstant())
 								.size());
 			}
 			if (0 != (includedOptions & SMUDGE))
 				if (entry.isSmudged())
 					sb.append(", smudged");
 			if (0 != (includedOptions & LENGTH))
 				sb.append(", length:"
 						+ Integer.toString(entry.getLength()));
 			if (0 != (includedOptions & CONTENT_ID))
 				sb.append(", sha1:" + ObjectId.toString(entry.getObjectId()));
 			if (0 != (includedOptions & CONTENT)) {
 				sb.append(", content:"
 						+ new String(repo.open(entry.getObjectId(),
 								Constants.OBJ_BLOB).getCachedBytes(), UTF_8));
 			}
 			if (0 != (includedOptions & ASSUME_UNCHANGED))
 				sb.append(", assume-unchanged:"
 						+ Boolean.toString(entry.isAssumeValid()));
 			sb.append("]");
 		}
 		return sb.toString();
 	}
 
 
 	/**
 	 * Creates a new empty bare repository.
 	 *
 	 * @return the newly created bare repository, opened for access. The
 	 *         repository will not be closed in {@link #tearDown()}; the caller
 	 *         is responsible for closing it.
 	 * @throws IOException
 	 *             the repository could not be created in the temporary area
 	 */
 	protected FileRepository createBareRepository() throws IOException {
 		return createRepository(true /* bare */);
 	}
 
 	/**
 	 * Creates a new empty repository within a new empty working directory.
 	 *
 	 * @return the newly created repository, opened for access. The repository
 	 *         will not be closed in {@link #tearDown()}; the caller is
 	 *         responsible for closing it.
 	 * @throws IOException
 	 *             the repository could not be created in the temporary area
 	 */
 	protected FileRepository createWorkRepository() throws IOException {
 		return createRepository(false /* not bare */);
 	}
 
 	/**
 	 * Creates a new empty repository.
 	 *
 	 * @param bare
 	 *            true to create a bare repository; false to make a repository
 	 *            within its working directory
 	 * @return the newly created repository, opened for access. The repository
 	 *         will not be closed in {@link #tearDown()}; the caller is
 	 *         responsible for closing it.
 	 * @throws IOException
 	 *             the repository could not be created in the temporary area
 	 * @since 5.3
 	 */
 	protected FileRepository createRepository(boolean bare)
 			throws IOException {
 		return createRepository(bare, false /* auto close */);
 	}
 
 	/**
 	 * Creates a new empty repository.
 	 *
 	 * @param bare
 	 *            true to create a bare repository; false to make a repository
 	 *            within its working directory
 	 * @param autoClose
 	 *            auto close the repository in {@link #tearDown()}
 	 * @return the newly created repository, opened for access
 	 * @throws IOException
 	 *             the repository could not be created in the temporary area
 	 * @deprecated use {@link #createRepository(boolean)} instead
 	 */
 	@Deprecated
 	public FileRepository createRepository(boolean bare, boolean autoClose)
 			throws IOException {
 		File gitdir = createUniqueTestGitDir(bare);
 		FileRepository db = new FileRepository(gitdir);
 		assertFalse(gitdir.exists());
 		db.create(bare);
 		if (autoClose) {
 			addRepoToClose(db);
 		}
 		return db;
 	}
 
 	/**
 	 * Adds a repository to the list of repositories which is closed at the end
 	 * of the tests
 	 *
 	 * @param r
 	 *            the repository to be closed
 	 */
 	public void addRepoToClose(Repository r) {
 		toClose.add(r);
 	}
 
 	/**
 	 * Creates a unique directory for a test
 	 *
 	 * @param name
 	 *            a subdirectory
 	 * @return a unique directory for a test
 	 * @throws IOException
 	 */
 	protected File createTempDirectory(String name) throws IOException {
 		File directory = new File(createTempFile(), name);
 		FileUtils.mkdirs(directory);
 		return directory.getCanonicalFile();
 	}
 
 	/**
 	 * Creates a new unique directory for a test repository
 	 *
 	 * @param bare
 	 *            true for a bare repository; false for a repository with a
 	 *            working directory
 	 * @return a unique directory for a test repository
 	 * @throws IOException
 	 */
 	protected File createUniqueTestGitDir(boolean bare) throws IOException {
 		String gitdirName = createTempFile().getPath();
 		if (!bare)
 			gitdirName += "/";
 		return new File(gitdirName + Constants.DOT_GIT);
 	}
 
 	/**
 	 * Allocates a new unique file path that does not exist.
 	 * <p>
 	 * Unlike the standard {@code File.createTempFile} the returned path does
 	 * not exist, but may be created by another thread in a race with the
 	 * caller. Good luck.
 	 * <p>
 	 * This method is inherently unsafe due to a race condition between creating
 	 * the name and the first use that reserves it.
 	 *
 	 * @return a unique path that does not exist.
 	 * @throws IOException
 	 */
 	protected File createTempFile() throws IOException {
 		File p = File.createTempFile("tmp_", "", tmp);
 		if (!p.delete()) {
 			throw new IOException("Cannot obtain unique path " + tmp);
 		}
 		return p;
 	}
 
 	/**
 	 * Run a hook script in the repository, returning the exit status.
 	 *
 	 * @param db
 	 *            repository the script should see in GIT_DIR environment
 	 * @param hook
 	 *            path of the hook script to execute, must be executable file
 	 *            type on this platform
 	 * @param args
 	 *            arguments to pass to the hook script
 	 * @return exit status code of the invoked hook
 	 * @throws IOException
 	 *             the hook could not be executed
 	 * @throws InterruptedException
 	 *             the caller was interrupted before the hook completed
 	 */
 	protected int runHook(final Repository db, final File hook,
 			final String... args) throws IOException, InterruptedException {
 		final String[] argv = new String[1 + args.length];
 		argv[0] = hook.getAbsolutePath();
 		System.arraycopy(args, 0, argv, 1, args.length);
 
 		final Map<String, String> env = cloneEnv();
 		env.put("GIT_DIR", db.getDirectory().getAbsolutePath());
 		putPersonIdent(env, "AUTHOR", author);
 		putPersonIdent(env, "COMMITTER", committer);
 
 		final File cwd = db.getWorkTree();
 		final Process p = Runtime.getRuntime().exec(argv, toEnvArray(env), cwd);
 		p.getOutputStream().close();
 		p.getErrorStream().close();
 		p.getInputStream().close();
 		return p.waitFor();
 	}
 
 	private static void putPersonIdent(final Map<String, String> env,
 			final String type, final PersonIdent who) {
 		final String ident = who.toExternalString();
 		final String date = ident.substring(ident.indexOf("> ") + 2);
 		env.put("GIT_" + type + "_NAME", who.getName());
 		env.put("GIT_" + type + "_EMAIL", who.getEmailAddress());
 		env.put("GIT_" + type + "_DATE", date);
 	}
 
 	/**
 	 * Create a string to a UTF-8 temporary file and return the path.
 	 *
 	 * @param body
 	 *            complete content to write to the file. If the file should end
 	 *            with a trailing LF, the string should end with an LF.
 	 * @return path of the temporary file created within the trash area.
 	 * @throws IOException
 	 *             the file could not be written.
 	 */
 	protected File write(String body) throws IOException {
 		final File f = File.createTempFile("temp", "txt", tmp);
 		try {
 			write(f, body);
 			return f;
 		} catch (Error | RuntimeException | IOException e) {
 			f.delete();
 			throw e;
 		}
 	}
 
 	/**
 	 * Write a string as a UTF-8 file.
 	 *
 	 * @param f
 	 *            file to write the string to. Caller is responsible for making
 	 *            sure it is in the trash directory or will otherwise be cleaned
 	 *            up at the end of the test. If the parent directory does not
 	 *            exist, the missing parent directories are automatically
 	 *            created.
 	 * @param body
 	 *            content to write to the file.
 	 * @throws IOException
 	 *             the file could not be written.
 	 */
 	protected void write(File f, String body) throws IOException {
 		JGitTestUtil.write(f, body);
 	}
 
 	/**
 	 * Read a file's content
 	 *
 	 * @param f
 	 *            the file
 	 * @return the content of the file
 	 * @throws IOException
 	 */
 	protected String read(File f) throws IOException {
 		return JGitTestUtil.read(f);
 	}
 
 	private static String[] toEnvArray(Map<String, String> env) {
 		final String[] envp = new String[env.size()];
 		int i = 0;
 		for (Map.Entry<String, String> e : env.entrySet())
 			envp[i++] = e.getKey() + "=" + e.getValue();
 		return envp;
 	}
 
 	private static HashMap<String, String> cloneEnv() {
 		return new HashMap<>(System.getenv());
 	}
 
 	private static final class CleanupThread extends Thread {
 		private static final CleanupThread me;
 		static {
 			me = new CleanupThread();
 			Runtime.getRuntime().addShutdownHook(me);
 		}
 
 		static void deleteOnShutdown(File tmp) {
 			synchronized (me) {
 				me.toDelete.add(tmp);
 			}
 		}
 
 		static void removed(File tmp) {
 			synchronized (me) {
 				me.toDelete.remove(tmp);
 			}
 		}
 
 		private final List<File> toDelete = new ArrayList<>();
 
 		@Override
 		public void run() {
 			// On windows accidentally open files or memory
 			// mapped regions may prevent files from being deleted.
 			// Suggesting a GC increases the likelihood that our
 			// test repositories actually get removed after the
 			// tests, even in the case of failure.
 			System.gc();
 			synchronized (this) {
 				boolean silent = false;
 				boolean failOnError = false;
 				for (File tmp : toDelete)
 					recursiveDelete(tmp, silent, failOnError);
 			}
 		}
 	}
 }