/*
    * Copyright (C) 2009, Google Inc.
    * Copyright (C) 2007-2008, Robin Rosenberg <robin.rosenberg@dewire.com>
    * Copyright (C) 2006-2007, Shawn O. Pearce <spearce@spearce.org>
    * Copyright (C) 2009, Yann Simon <yann.simon.fr@gmail.com> 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.assertEquals;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.Reader;
  import java.nio.file.Path;
  import java.time.Instant;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  
  import org.eclipse.jgit.api.Git;
  import org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.dircache.DirCacheBuilder;
  import org.eclipse.jgit.dircache.DirCacheCheckout;
  import org.eclipse.jgit.dircache.DirCacheEntry;
  import org.eclipse.jgit.internal.storage.file.FileRepository;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.FileMode;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ObjectInserter;
  import org.eclipse.jgit.lib.RefUpdate;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.treewalk.FileTreeIterator;
  import org.eclipse.jgit.util.FS;
  import org.eclipse.jgit.util.FileUtils;
  import org.junit.Before;
  
  /**
   * Base class for most JGit unit tests.
   *
   * Sets up a predefined test repository and has support for creating additional
   * repositories and destroying them when the tests are finished.
   */
  public abstract class RepositoryTestCase extends LocalDiskRepositoryTestCase {
  	/**
  	 * Copy a file
  	 *
  	 * @param src
  	 * @param dst
  	 * @throws IOException
  	 */
  	protected static void copyFile(File src, File dst)
  			throws IOException {
  		try (FileInputStream fis = new FileInputStream(src);
  				FileOutputStream fos = new FileOutputStream(dst)) {
  			final byte[] buf = new byte[4096];
  			int r;
  			while ((r = fis.read(buf)) > 0) {
  				fos.write(buf, 0, r);
  			}
  		}
  	}
  
  	/**
  	 * Write a trash file
  	 *
  	 * @param name
  	 * @param data
  	 * @return the trash file
  	 * @throws IOException
  	 */
  	protected File writeTrashFile(String name, String data)
  			throws IOException {
  		return JGitTestUtil.writeTrashFile(db, name, data);
  	}
  
  	/**
  	 * Create a symbolic link
  	 *
  	 * @param link
  	 *            the path of the symbolic link to create
  	 * @param target
  	 *            the target of the symbolic link
  	 * @return the path to the symbolic link
  	 * @throws Exception
  	 * @since 4.2
  	 */
 	protected Path writeLink(String link, String target)
 			throws Exception {
 		return JGitTestUtil.writeLink(db, link, target);
 	}
 
 	/**
 	 * Write a trash file
 	 *
 	 * @param subdir
 	 * @param name
 	 * @param data
 	 * @return the trash file
 	 * @throws IOException
 	 */
 	protected File writeTrashFile(final String subdir, final String name,
 			final String data)
 			throws IOException {
 		return JGitTestUtil.writeTrashFile(db, subdir, name, data);
 	}
 
 	/**
 	 * Read content of a file
 	 *
 	 * @param name
 	 * @return the file's content
 	 * @throws IOException
 	 */
 	protected String read(String name) throws IOException {
 		return JGitTestUtil.read(db, name);
 	}
 
 	/**
 	 * Check if file exists
 	 *
 	 * @param name
 	 *            file name
 	 * @return if the file exists
 	 */
 	protected boolean check(String name) {
 		return JGitTestUtil.check(db, name);
 	}
 
 	/**
 	 * Delete a trash file
 	 *
 	 * @param name
 	 *            file name
 	 * @throws IOException
 	 */
 	protected void deleteTrashFile(String name) throws IOException {
 		JGitTestUtil.deleteTrashFile(db, name);
 	}
 
 	/**
 	 * Check content of a file.
 	 *
 	 * @param f
 	 * @param checkData
 	 *            expected content
 	 * @throws IOException
 	 */
 	protected static void checkFile(File f, String checkData)
 			throws IOException {
 		try (Reader r = new InputStreamReader(new FileInputStream(f),
 				UTF_8)) {
 			if (checkData.length() > 0) {
 				char[] data = new char[checkData.length()];
 				assertEquals(data.length, r.read(data));
 				assertEquals(checkData, new String(data));
 			}
 			assertEquals(-1, r.read());
 		}
 	}
 
 	/** Test repository, initialized for this test case. */
 	protected FileRepository db;
 
 	/** Working directory of {@link #db}. */
 	protected File trash;
 
 	/** {@inheritDoc} */
 	@Override
 	@Before
 	public void setUp() throws Exception {
 		super.setUp();
 		db = createWorkRepository();
 		trash = db.getWorkTree();
 	}
 
 	/**
 	 * 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 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 String indexState(int includedOptions)
 			throws IllegalStateException, IOException {
 		return indexState(db, includedOptions);
 	}
 
 	/**
 	 * Resets the index to represent exactly some filesystem content. E.g. the
 	 * following call will replace the index with the working tree content:
 	 * <p>
 	 * <code>resetIndex(new FileSystemIterator(db))</code>
 	 * <p>
 	 * This method can be used by testcases which first prepare a new commit
 	 * somewhere in the filesystem (e.g. in the working-tree) and then want to
 	 * have an index which matches their prepared content.
 	 *
 	 * @param treeItr
 	 *            a {@link org.eclipse.jgit.treewalk.FileTreeIterator} which
 	 *            determines which files should go into the new index
 	 * @throws FileNotFoundException
 	 * @throws IOException
 	 */
 	protected void resetIndex(FileTreeIterator treeItr)
 			throws FileNotFoundException, IOException {
 		try (ObjectInserter inserter = db.newObjectInserter()) {
 			DirCacheBuilder builder = db.lockDirCache().builder();
 			DirCacheEntry dce;
 
 			while (!treeItr.eof()) {
 				long len = treeItr.getEntryLength();
 
 				dce = new DirCacheEntry(treeItr.getEntryPathString());
 				dce.setFileMode(treeItr.getEntryFileMode());
 				dce.setLastModified(treeItr.getEntryLastModifiedInstant());
 				dce.setLength((int) len);
 				try (FileInputStream in = new FileInputStream(
 						treeItr.getEntryFile())) {
 					dce.setObjectId(
 							inserter.insert(Constants.OBJ_BLOB, len, in));
 				}
 				builder.add(dce);
 				treeItr.next(1);
 			}
 			builder.commit();
 			inserter.flush();
 		}
 	}
 
 	/**
 	 * Helper method to map arbitrary objects to user-defined names. This can be
 	 * used create short names for objects to produce small and stable debug
 	 * output. It is guaranteed that when you lookup the same object multiple
 	 * times even with different nameTemplates this method will always return
 	 * the same name which was derived from the first nameTemplate.
 	 * nameTemplates can contain "%n" which will be replaced by a running number
 	 * before used as a name.
 	 *
 	 * @param l
 	 *            the object to lookup
 	 * @param lookupTable
 	 *            a table storing object-name mappings.
 	 * @param nameTemplate
 	 *            the name for that object. Can contain "%n" which will be
 	 *            replaced by a running number before used as a name. If the
 	 *            lookup table already contains the object this parameter will
 	 *            be ignored
 	 * @return a name of that object. Is not guaranteed to be unique. Use
 	 *         nameTemplates containing "%n" to always have unique names
 	 */
 	public static String lookup(Object l, String nameTemplate,
 			Map<Object, String> lookupTable) {
 		String name = lookupTable.get(l);
 		if (name == null) {
 			name = nameTemplate.replaceAll("%n",
 					Integer.toString(lookupTable.size()));
 			lookupTable.put(l, name);
 		}
 		return name;
 	}
 
 	/**
 	 * Replaces '\' by '/'
 	 *
 	 * @param str
 	 *            the string in which backslashes should be replaced
 	 * @return the resulting string with slashes
 	 * @since 4.2
 	 */
 	public static String slashify(String str) {
 		str = str.replace('\\', '/');
 		return str;
 	}
 
 	/**
 	 * Waits until it is guaranteed that a subsequent file modification has a
 	 * younger modification timestamp than the modification timestamp of the
 	 * given file. This is done by touching a temporary file, reading the
 	 * lastmodified attribute and, if needed, sleeping. After sleeping this loop
 	 * starts again until the filesystem timer has advanced enough. The
 	 * temporary file will be created as a sibling of lastFile.
 	 *
 	 * @param lastFile
 	 *            the file on which we want to wait until the filesystem timer
 	 *            has advanced more than the lastmodification timestamp of this
 	 *            file
 	 * @return return the last measured value of the filesystem timer which is
 	 *         greater than then the lastmodification time of lastfile.
 	 * @throws InterruptedException
 	 * @throws IOException
 	 */
 	public static Instant fsTick(File lastFile)
 			throws InterruptedException,
 			IOException {
 		File tmp;
 		FS fs = FS.DETECTED;
 		if (lastFile == null) {
 			lastFile = tmp = File
 					.createTempFile("fsTickTmpFile", null);
 		} else {
 			if (!fs.exists(lastFile)) {
 				throw new FileNotFoundException(lastFile.getPath());
 			}
 			tmp = File.createTempFile("fsTickTmpFile", null,
 					lastFile.getParentFile());
 		}
 		long res = FS.getFileStoreAttributes(tmp.toPath())
 				.getFsTimestampResolution().toNanos();
 		long sleepTime = res / 10;
 		try {
 			Instant startTime = fs.lastModifiedInstant(lastFile);
 			Instant actTime = fs.lastModifiedInstant(tmp);
 			while (actTime.compareTo(startTime) <= 0) {
 				TimeUnit.NANOSECONDS.sleep(sleepTime);
 				FileUtils.touch(tmp.toPath());
 				actTime = fs.lastModifiedInstant(tmp);
 			}
 			return actTime;
 		} finally {
 			FileUtils.delete(tmp);
 		}
 	}
 
 	/**
 	 * Create a branch
 	 *
 	 * @param objectId
 	 * @param branchName
 	 * @throws IOException
 	 */
 	protected void createBranch(ObjectId objectId, String branchName)
 			throws IOException {
 		RefUpdate updateRef = db.updateRef(branchName);
 		updateRef.setNewObjectId(objectId);
 		updateRef.update();
 	}
 
 	/**
 	 * Checkout a branch
 	 *
 	 * @param branchName
 	 * @throws IllegalStateException
 	 * @throws IOException
 	 */
 	protected void checkoutBranch(String branchName)
 			throws IllegalStateException, IOException {
 		try (RevWalk walk = new RevWalk(db)) {
 			RevCommit head = walk.parseCommit(db.resolve(Constants.HEAD));
 			RevCommit branch = walk.parseCommit(db.resolve(branchName));
 			DirCacheCheckout dco = new DirCacheCheckout(db,
 					head.getTree().getId(), db.lockDirCache(),
 					branch.getTree().getId());
 			dco.setFailOnConflict(true);
 			dco.checkout();
 		}
 		// update the HEAD
 		RefUpdate refUpdate = db.updateRef(Constants.HEAD);
 		refUpdate.setRefLogMessage("checkout: moving to " + branchName, false);
 		refUpdate.link(branchName);
 	}
 
 	/**
 	 * Writes a number of files in the working tree. The first content specified
 	 * will be written into a file named '0', the second into a file named "1"
 	 * and so on. If <code>null</code> is specified as content then this file is
 	 * skipped.
 	 *
 	 * @param ensureDistinctTimestamps
 	 *            if set to <code>true</code> then between two write operations
 	 *            this method will wait to ensure that the second file will get
 	 *            a different lastmodification timestamp than the first file.
 	 * @param contents
 	 *            the contents which should be written into the files
 	 * @return the File object associated to the last written file.
 	 * @throws IOException
 	 * @throws InterruptedException
 	 */
 	protected File writeTrashFiles(boolean ensureDistinctTimestamps,
 			String... contents)
 			throws IOException, InterruptedException {
 				File f = null;
 				for (int i = 0; i < contents.length; i++)
 					if (contents[i] != null) {
 						if (ensureDistinctTimestamps && (f != null))
 							fsTick(f);
 						f = writeTrashFile(Integer.toString(i), contents[i]);
 					}
 				return f;
 			}
 
 	/**
 	 * Commit a file with the specified contents on the specified branch,
 	 * creating the branch if it didn't exist before.
 	 * <p>
 	 * It switches back to the original branch after the commit if there was
 	 * one.
 	 *
 	 * @param filename
 	 * @param contents
 	 * @param branch
 	 * @return the created commit
 	 */
 	protected RevCommit commitFile(String filename, String contents, String branch) {
 		try (Git git = new Git(db)) {
 			Repository repo = git.getRepository();
 			String originalBranch = repo.getFullBranch();
 			boolean empty = repo.resolve(Constants.HEAD) == null;
 			if (!empty) {
 				if (repo.findRef(branch) == null)
 					git.branchCreate().setName(branch).call();
 				git.checkout().setName(branch).call();
 			}
 
 			writeTrashFile(filename, contents);
 			git.add().addFilepattern(filename).call();
 			RevCommit commit = git.commit()
 					.setMessage(branch + ": " + filename).call();
 
 			if (originalBranch != null)
 				git.checkout().setName(originalBranch).call();
 			else if (empty)
 				git.branchCreate().setName(branch).setStartPoint(commit).call();
 
 			return commit;
 		} catch (IOException | GitAPIException e) {
 			throw new RuntimeException(e);
 		}
 	}
 
 	/**
 	 * Create <code>DirCacheEntry</code>
 	 *
 	 * @param path
 	 * @param mode
 	 * @return the DirCacheEntry
 	 */
 	protected DirCacheEntry createEntry(String path, FileMode mode) {
 		return createEntry(path, mode, DirCacheEntry.STAGE_0, path);
 	}
 
 	/**
 	 * Create <code>DirCacheEntry</code>
 	 *
 	 * @param path
 	 * @param mode
 	 * @param content
 	 * @return the DirCacheEntry
 	 */
 	protected DirCacheEntry createEntry(final String path, final FileMode mode,
 			final String content) {
 		return createEntry(path, mode, DirCacheEntry.STAGE_0, content);
 	}
 
 	/**
 	 * Create <code>DirCacheEntry</code>
 	 *
 	 * @param path
 	 * @param mode
 	 * @param stage
 	 * @param content
 	 * @return the DirCacheEntry
 	 */
 	protected DirCacheEntry createEntry(final String path, final FileMode mode,
 			final int stage, final String content) {
 		final DirCacheEntry entry = new DirCacheEntry(path, stage);
 		entry.setFileMode(mode);
 		try (ObjectInserter.Formatter formatter = new ObjectInserter.Formatter()) {
 			entry.setObjectId(formatter.idFor(
 					Constants.OBJ_BLOB, Constants.encode(content)));
 		}
 		return entry;
 	}
 
 	/**
 	 * Assert files are equal
 	 *
 	 * @param expected
 	 * @param actual
 	 * @throws IOException
 	 */
 	public static void assertEqualsFile(File expected, File actual)
 			throws IOException {
 		assertEquals(expected.getCanonicalFile(), actual.getCanonicalFile());
 	}
 }