/*
 * Copyright (C) 2015, 2020 Ivan Motsch <ivan.motsch@bsiag.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.api;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.eclipse.jgit.lib.CoreConfig.EolStreamType.AUTO_CRLF;
import static org.eclipse.jgit.lib.CoreConfig.EolStreamType.AUTO_LF;
import static org.eclipse.jgit.lib.CoreConfig.EolStreamType.DIRECT;
import static org.eclipse.jgit.lib.CoreConfig.EolStreamType.TEXT_CRLF;
import static org.eclipse.jgit.lib.CoreConfig.EolStreamType.TEXT_LF;
import static org.junit.Assert.assertArrayEquals;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;

import org.eclipse.jgit.lib.CoreConfig.EolStreamType;
import org.eclipse.jgit.util.IO;
import org.eclipse.jgit.util.io.EolStreamTypeUtil;
import org.junit.Test;

/**
 * Unit tests for end-of-line conversion streams
 */
public class EolStreamTypeUtilTest {

	@Test
	public void testCheckoutDirect() throws Exception {
		testCheckout(DIRECT, DIRECT, "", "");
		testCheckout(DIRECT, DIRECT, "\r", "\r");
		testCheckout(DIRECT, DIRECT, "\n", "\n");

		testCheckout(DIRECT, DIRECT, "\r\n", "\r\n");
		testCheckout(DIRECT, DIRECT, "\n\r", "\n\r");

		testCheckout(DIRECT, DIRECT, "\n\r\n", "\n\r\n");
		testCheckout(DIRECT, DIRECT, "\r\n\r", "\r\n\r");

		testCheckout(DIRECT, DIRECT, "a\nb\n", "a\nb\n");
		testCheckout(DIRECT, DIRECT, "a\rb\r", "a\rb\r");
		testCheckout(DIRECT, DIRECT, "a\n\rb\n\r", "a\n\rb\n\r");
		testCheckout(DIRECT, DIRECT, "a\r\nb\r\n", "a\r\nb\r\n");
	}

	@Test
	public void testCheckoutLF() throws Exception {
		testCheckout(TEXT_LF, AUTO_LF, "", "");
		testCheckout(TEXT_LF, AUTO_LF, "\r", "\r");
		testCheckout(TEXT_LF, AUTO_LF, "\n", "\n");

		testCheckout(TEXT_LF, null, "\r\n", "\n");
		testCheckout(null, AUTO_LF, "\r\n", "\r\n");
		testCheckout(TEXT_LF, AUTO_LF, "\n\r", "\n\r");

		testCheckout(TEXT_LF, null, "\n\r\n", "\n\n");
		testCheckout(null, AUTO_LF, "\n\r\n", "\n\r\n");
		testCheckout(TEXT_LF, null, "\r\n\r", "\n\r");
		testCheckout(null, AUTO_LF, "\r\n\r", "\r\n\r");

		testCheckout(TEXT_LF, AUTO_LF, "a\nb\n", "a\nb\n");
		testCheckout(TEXT_LF, AUTO_LF, "a\rb\r", "a\rb\r");
		testCheckout(TEXT_LF, AUTO_LF, "a\n\rb\n\r", "a\n\rb\n\r");
		testCheckout(TEXT_LF, null, "a\r\nb\r\n", "a\nb\n");
		testCheckout(null, AUTO_LF, "a\r\nb\r\n", "a\r\nb\r\n");
	}

	@Test
	public void testCheckoutCRLF() throws Exception {
		testCheckout(TEXT_CRLF, AUTO_CRLF, "", "");
		testCheckout(TEXT_CRLF, AUTO_CRLF, "\r", "\r");
		testCheckout(TEXT_CRLF, AUTO_CRLF, "\n", "\r\n");

		testCheckout(TEXT_CRLF, AUTO_CRLF, "\r\n", "\r\n");
		testCheckout(TEXT_CRLF, null, "\n\r", "\r\n\r");
		testCheckout(null, AUTO_CRLF, "\n\r", "\n\r"); // Lone CR

		testCheckout(null, AUTO_CRLF, "\n\r\n", "\n\r\n");
		testCheckout(TEXT_CRLF, null, "\n\r\n", "\r\n\r\n");
		testCheckout(TEXT_CRLF, AUTO_CRLF, "\r\n\r", "\r\n\r");

		testCheckout(TEXT_CRLF, AUTO_CRLF, "a\nb\n", "a\r\nb\r\n");
		testCheckout(TEXT_CRLF, AUTO_CRLF, "a\rb\r", "a\rb\r");
		testCheckout(TEXT_CRLF, null, "a\n\rb\n\r", "a\r\n\rb\r\n\r");
		testCheckout(null, AUTO_CRLF, "a\n\rb\n\r", "a\n\rb\n\r"); // Lone CR
		testCheckout(TEXT_CRLF, AUTO_CRLF, "a\r\nb\r\n", "a\r\nb\r\n");
	}

	/**
	 * Test stream type detection based on stream content.
	 * <p>
	 * Tests three things with the output text:
	 * <p>
	 * 1) conversion if output was declared as text
	 * <p>
	 * 2) conversion if output was declared as potentially text (AUTO_...) and
	 * is in fact text
	 * <p>
	 * 3) conversion if modified output (now with binary characters) was
	 * declared as potentially text but now contains binary characters
	 * <p>
	 *
	 * @param streamTypeText
	 *            is the enum meaning that the output is definitely text (no
	 *            binary check at all)
	 * @param streamTypeWithBinaryCheck
	 *            is the enum meaning that the output may be text (binary check
	 *            is done)
	 * @param output
	 *            is a text output without binary characters
	 * @param expectedConversion
	 *            is the expected converted output without binary characters
	 * @throws Exception
	 */
	private void testCheckout(EolStreamType streamTypeText,
			EolStreamType streamTypeWithBinaryCheck, String output,
			String expectedConversion) throws Exception {
		ByteArrayOutputStream b;
		byte[] outputBytes = output.getBytes(UTF_8);
		byte[] expectedConversionBytes = expectedConversion.getBytes(UTF_8);

		if (streamTypeText != null) {
			// test using output text and assuming it was declared TEXT
			b = new ByteArrayOutputStream();
			try (OutputStream out = EolStreamTypeUtil.wrapOutputStream(b,
					streamTypeText)) {
				out.write(outputBytes);
			}
			assertArrayEquals(expectedConversionBytes, b.toByteArray());
		}
		if (streamTypeWithBinaryCheck != null) {
			// test using output text and assuming it was declared AUTO, using
			// binary detection
			b = new ByteArrayOutputStream();
			try (OutputStream out = EolStreamTypeUtil.wrapOutputStream(b,
					streamTypeWithBinaryCheck)) {
				out.write(outputBytes);
			}
			assertArrayEquals(expectedConversionBytes, b.toByteArray());
		}
		// now pollute output text with some binary bytes
		outputBytes = extendWithBinaryData(outputBytes);
		expectedConversionBytes = extendWithBinaryData(expectedConversionBytes);

		if (streamTypeText != null) {
			// again, test using output text and assuming it was declared TEXT
			b = new ByteArrayOutputStream();
			try (OutputStream out = EolStreamTypeUtil.wrapOutputStream(b,
					streamTypeText)) {
				out.write(outputBytes);
			}
			assertArrayEquals(expectedConversionBytes, b.toByteArray());
		}
		if (streamTypeWithBinaryCheck != null) {
			// again, test using output text and assuming it was declared AUTO,
			// using binary detection
			b = new ByteArrayOutputStream();
			try (OutputStream out = EolStreamTypeUtil.wrapOutputStream(b,
					streamTypeWithBinaryCheck)) {
				out.write(outputBytes);
			}
			// expect no conversion
			assertArrayEquals(outputBytes, b.toByteArray());
		}
	}

	@Test
	public void testCheckinDirect() throws Exception {
		testCheckin(DIRECT, DIRECT, "", "");
		testCheckin(DIRECT, DIRECT, "\r", "\r");
		testCheckin(DIRECT, DIRECT, "\n", "\n");

		testCheckin(DIRECT, DIRECT, "\r\n", "\r\n");
		testCheckin(DIRECT, DIRECT, "\n\r", "\n\r");

		testCheckin(DIRECT, DIRECT, "\n\r\n", "\n\r\n");
		testCheckin(DIRECT, DIRECT, "\r\n\r", "\r\n\r");

		testCheckin(DIRECT, DIRECT, "a\nb\n", "a\nb\n");
		testCheckin(DIRECT, DIRECT, "a\rb\r", "a\rb\r");
		testCheckin(DIRECT, DIRECT, "a\n\rb\n\r", "a\n\rb\n\r");
		testCheckin(DIRECT, DIRECT, "a\r\nb\r\n", "a\r\nb\r\n");
	}

	@Test
	public void testCheckinLF() throws Exception {
		testCheckin(TEXT_LF, AUTO_LF, "", "");
		testCheckin(TEXT_LF, AUTO_LF, "\r", "\r");
		testCheckin(TEXT_LF, AUTO_LF, "\n", "\n");

		testCheckin(TEXT_LF, AUTO_LF, "\r\n", "\n");
		testCheckin(TEXT_LF, AUTO_LF, "\n\r", "\n\r");

		testCheckin(TEXT_LF, AUTO_LF, "\n\r\n", "\n\n");
		testCheckin(TEXT_LF, null, "\r\n\r", "\n\r");
		testCheckin(null, AUTO_LF, "\r\n\r", "\r\n\r"); // Lone CR

		testCheckin(TEXT_LF, AUTO_LF, "a\nb\n", "a\nb\n");
		testCheckin(TEXT_LF, AUTO_LF, "a\rb\r", "a\rb\r");
		testCheckin(TEXT_LF, AUTO_LF, "a\n\rb\n\r", "a\n\rb\n\r");
		testCheckin(TEXT_LF, AUTO_LF, "a\r\nb\r\n", "a\nb\n");
	}

	@Test
	public void testCheckinCRLF() throws Exception {
		testCheckin(TEXT_CRLF, AUTO_CRLF, "", "");
		testCheckin(TEXT_CRLF, AUTO_CRLF, "\r", "\r");
		testCheckin(TEXT_CRLF, AUTO_CRLF, "\n", "\r\n");

		testCheckin(TEXT_CRLF, AUTO_CRLF, "\r\n", "\r\n");
		testCheckin(TEXT_CRLF, null, "\n\r", "\r\n\r");
		testCheckin(null, AUTO_CRLF, "\n\r", "\n\r"); // Lone CR

		testCheckin(TEXT_CRLF, AUTO_CRLF, "\n\r\n", "\r\n\r\n");
		testCheckin(TEXT_CRLF, AUTO_CRLF, "\r\n\r", "\r\n\r");

		testCheckin(TEXT_CRLF, AUTO_CRLF, "a\nb\n", "a\r\nb\r\n");
		testCheckin(TEXT_CRLF, AUTO_CRLF, "a\rb\r", "a\rb\r");
		testCheckin(TEXT_CRLF, null, "a\n\rb\n\r", "a\r\n\rb\r\n\r");
		testCheckin(null, AUTO_CRLF, "a\n\rb\n\r", "a\n\rb\n\r"); // Lone CR
		testCheckin(TEXT_CRLF, AUTO_CRLF, "a\r\nb\r\n", "a\r\nb\r\n");
	}

	/**
	 * Test stream type detection based on stream content.
	 * <p>
	 * Tests three things with the input text:
	 * <p>
	 * 1) conversion if input was declared as text
	 * <p>
	 * 2) conversion if input was declared as potentially text (AUTO_...) and is
	 * in fact text
	 * <p>
	 * 3) conversion if modified input (now with binary characters) was declared
	 * as potentially text but now contains binary characters
	 * <p>
	 *
	 * @param streamTypeText
	 *            is the enum meaning that the input is definitely text (no
	 *            binary check at all)
	 * @param streamTypeWithBinaryCheck
	 *            is the enum meaning that the input may be text (binary check
	 *            is done)
	 * @param input
	 *            is a text input without binary characters
	 * @param expectedConversion
	 *            is the expected converted input without binary characters
	 * @throws Exception
	 */
	private void testCheckin(EolStreamType streamTypeText,
			EolStreamType streamTypeWithBinaryCheck, String input,
			String expectedConversion) throws Exception {
		byte[] inputBytes = input.getBytes(UTF_8);
		byte[] expectedConversionBytes = expectedConversion.getBytes(UTF_8);

		if (streamTypeText != null) {
			// test using input text and assuming it was declared TEXT
			try (InputStream in = EolStreamTypeUtil.wrapInputStream(
					new ByteArrayInputStream(inputBytes), streamTypeText)) {
				byte[] b = new byte[1024];
				int len = IO.readFully(in, b, 0);
				assertArrayEquals(expectedConversionBytes,
						Arrays.copyOf(b, len));
			}
		}

		if (streamTypeWithBinaryCheck != null) {
			// test using input text and assuming it was declared AUTO, using
			// binary detection
			try (InputStream in = EolStreamTypeUtil.wrapInputStream(
					new ByteArrayInputStream(inputBytes),
					streamTypeWithBinaryCheck)) {
				byte[] b = new byte[1024];
				int len = IO.readFully(in, b, 0);
				assertArrayEquals(expectedConversionBytes,
						Arrays.copyOf(b, len));
			}
		}
		// now pollute input text with some binary bytes
		inputBytes = extendWithBinaryData(inputBytes);
		expectedConversionBytes = extendWithBinaryData(expectedConversionBytes);

		if (streamTypeText != null) {
			// again, test using input text and assuming it was declared TEXT
			try (InputStream in = EolStreamTypeUtil.wrapInputStream(
					new ByteArrayInputStream(inputBytes), streamTypeText)) {
				byte[] b = new byte[1024];
				int len = IO.readFully(in, b, 0);
				assertArrayEquals(expectedConversionBytes,
						Arrays.copyOf(b, len));
			}
		}

		if (streamTypeWithBinaryCheck != null) {
			// again, test using input text and assuming it was declared AUTO,
			// using binary detection
			try (InputStream in = EolStreamTypeUtil.wrapInputStream(
					new ByteArrayInputStream(inputBytes),
					streamTypeWithBinaryCheck)) {
				byte[] b = new byte[1024];
				int len = IO.readFully(in, b, 0);
				// expect no conversion
				assertArrayEquals(inputBytes, Arrays.copyOf(b, len));
			}
		}
	}

	private byte[] extendWithBinaryData(byte[] data) throws Exception {
		int n = 3;
		byte[] dataEx = new byte[data.length + n];
		System.arraycopy(data, 0, dataEx, 0, data.length);
		for (int i = 0; i < n; i++) {
			dataEx[data.length + i] = (byte) i;
		}
		return dataEx;
	}

}