/*
    * Copyright (C) 2008-2009, Google Inc.
    * Copyright (C) 2008, Imran M Yousuf <imyousuf@smartitengineering.com>
    * Copyright (C) 2008, Jonas Fonseca <fonseca@diku.dk> 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 java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStreamWriter;
  import java.io.Writer;
  import java.lang.reflect.Method;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.nio.file.Path;
  
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.util.FileUtils;
  import org.eclipse.jgit.util.IO;
  import org.eclipse.jgit.util.RawParseUtils;
  import org.junit.Assert;
  import org.junit.Test;
  
  /**
   * Abstract test util class
   */
  public abstract class JGitTestUtil {
  	/** Constant <code>CLASSPATH_TO_RESOURCES="org/eclipse/jgit/test/resources/"</code> */
  	public static final String CLASSPATH_TO_RESOURCES = "org/eclipse/jgit/test/resources/";
  
  	private JGitTestUtil() {
  		throw new UnsupportedOperationException();
  	}
  
  	/**
  	 * Get name of current test by inspecting stack trace
  	 *
  	 * @return the name
  	 */
  	public static String getName() {
  		GatherStackTrace stack;
  		try {
  			throw new GatherStackTrace();
  		} catch (GatherStackTrace wanted) {
  			stack = wanted;
  		}
  
  		try {
  			for (StackTraceElement stackTrace : stack.getStackTrace()) {
  				String className = stackTrace.getClassName();
  				String methodName = stackTrace.getMethodName();
  				Method method;
  				try {
  					method = Class.forName(className) //
  							.getMethod(methodName, (Class[]) null);
  				} catch (NoSuchMethodException e) {
  					// could be private, i.e. not a test method
  					// could have arguments, not handled
  					continue;
  				}
  
  				Test annotation = method.getAnnotation(Test.class);
  				if (annotation != null)
  					return methodName;
  			}
  		} catch (ClassNotFoundException shouldNeverOccur) {
  			// Fall through and crash.
  		}
  
  		throw new AssertionError("Cannot determine name of current test");
  	}
  
  	@SuppressWarnings("serial")
  	private static class GatherStackTrace extends Exception {
  		// Thrown above to collect the stack frame.
  	}
  
  	/**
  	 * Assert byte arrays are equal
  	 *
  	 * @param exp
  	 *            expected value
  	 * @param act
  	 *            actual value
  	 */
  	public static void assertEquals(byte[] exp, byte[] act) {
  		Assert.assertEquals(s(exp), s(act));
 	}
 
 	private static String s(byte[] raw) {
 		return RawParseUtils.decode(raw);
 	}
 
 	/**
 	 * Get test resource file.
 	 *
 	 * @param fileName
 	 * @return the test resource file
 	 */
 	public static File getTestResourceFile(String fileName) {
 		if (fileName == null || fileName.length() <= 0) {
 			return null;
 		}
 		final URL url = cl().getResource(CLASSPATH_TO_RESOURCES + fileName);
 		if (url == null) {
 			// If URL is null then try to load it as it was being
 			// loaded previously
 			return new File("tst", fileName);
 		}
 		if ("jar".equals(url.getProtocol())) {
 			try {
 				File tmp = File.createTempFile("tmp_", "_" + fileName);
 				copyTestResource(fileName, tmp);
 				return tmp;
 			} catch (IOException err) {
 				throw new RuntimeException("Cannot create temporary file", err);
 			}
 		}
 		try {
 			return new File(url.toURI());
 		} catch (IllegalArgumentException e) {
 			throw new IllegalArgumentException(e.getMessage() + " " + url);
 		} catch (URISyntaxException e) {
 			return new File(url.getPath());
 		}
 	}
 
 	/**
 	 * Copy test resource.
 	 *
 	 * @param name
 	 * @param dest
 	 * @throws IOException
 	 */
 	public static void copyTestResource(String name, File dest)
 			throws IOException {
 		URL url = cl().getResource(CLASSPATH_TO_RESOURCES + name);
 		if (url == null)
 			throw new FileNotFoundException(name);
 		try (InputStream in = url.openStream();
 				FileOutputStream out = new FileOutputStream(dest)) {
 			byte[] buf = new byte[4096];
 			for (int n; (n = in.read(buf)) > 0;)
 				out.write(buf, 0, n);
 		}
 	}
 
 	private static ClassLoader cl() {
 		return JGitTestUtil.class.getClassLoader();
 	}
 
 	/**
 	 * Write a trash file.
 	 *
 	 * @param db
 	 * @param name
 	 * @param data
 	 * @return the trash file
 	 * @throws IOException
 	 */
 	public static File writeTrashFile(final Repository db,
 			final String name, final String data) throws IOException {
 		File path = new File(db.getWorkTree(), name);
 		write(path, data);
 		return path;
 	}
 
 	/**
 	 * Write a trash file.
 	 *
 	 * @param db
 	 * @param subdir
 	 * @param name
 	 * @param data
 	 * @return the trash file
 	 * @throws IOException
 	 */
 	public static File writeTrashFile(final Repository db,
 			final String subdir,
 			final String name, final String data) throws IOException {
 		File path = new File(db.getWorkTree() + "/" + subdir, name);
 		write(path, data);
 		return path;
 	}
 
 	/**
 	 * 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.
 	 */
 	public static void write(File f, String body)
 			throws IOException {
 		FileUtils.mkdirs(f.getParentFile(), true);
 		try (Writer w = new OutputStreamWriter(new FileOutputStream(f),
 				UTF_8)) {
 			w.write(body);
 		}
 	}
 
 	/**
 	 * Fully read a UTF-8 file and return as a string.
 	 *
 	 * @param file
 	 *            file to read the content of.
 	 * @return UTF-8 decoded content of the file, empty string if the file
 	 *         exists but has no content.
 	 * @throws IOException
 	 *             the file does not exist, or could not be read.
 	 */
 	public static String read(File file) throws IOException {
 		final byte[] body = IO.readFully(file);
 		return new String(body, 0, body.length, UTF_8);
 	}
 
 	/**
 	 * Read a file's content
 	 *
 	 * @param db
 	 * @param name
 	 * @return the content of the file
 	 * @throws IOException
 	 */
 	public static String read(Repository db, String name)
 			throws IOException {
 		File file = new File(db.getWorkTree(), name);
 		return read(file);
 	}
 
 	/**
 	 * Check if file exists
 	 *
 	 * @param db
 	 * @param name
 	 *            name of the file
 	 * @return {@code true} if the file exists
 	 */
 	public static boolean check(Repository db, String name) {
 		File file = new File(db.getWorkTree(), name);
 		return file.exists();
 	}
 
 	/**
 	 * Delete a trash file.
 	 *
 	 * @param db
 	 * @param name
 	 * @throws IOException
 	 */
 	public static void deleteTrashFile(final Repository db,
 			final String name) throws IOException {
 		File path = new File(db.getWorkTree(), name);
 		FileUtils.delete(path);
 	}
 
 	/**
 	 * Write a symbolic link
 	 *
 	 * @param db
 	 *            the repository
 	 * @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
 	 */
 	public static Path writeLink(Repository db, String link,
 			String target) throws Exception {
 		return FileUtils.createSymLink(new File(db.getWorkTree(), link),
 				target);
 	}
 
 	/**
 	 * Concatenate byte arrays.
 	 *
 	 * @param b
 	 *            byte arrays to combine together.
 	 * @return a single byte array that contains all bytes copied from input
 	 *         byte arrays.
 	 * @since 4.9
 	 */
 	public static byte[] concat(byte[]... b) {
 		int n = 0;
 		for (byte[] a : b) {
 			n += a.length;
 		}
 
 		byte[] data = new byte[n];
 		n = 0;
 		for (byte[] a : b) {
 			System.arraycopy(a, 0, data, n, a.length);
 			n += a.length;
 		}
 		return data;
 	}
 }