/*
 * Copyright (C) 2008, 2024 Google Inc. 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.revwalk;

import static java.nio.charset.StandardCharsets.ISO_8859_1;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.time.Instant;
import java.time.ZoneId;
import java.time.ZoneOffset;

import org.eclipse.jgit.junit.RepositoryTestCase;
import org.eclipse.jgit.lib.CommitBuilder;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.PersonIdent;
import org.junit.Test;

public class RevCommitParseTest extends RepositoryTestCase {
	@Test
	public void testParse_NoParents() throws Exception {
		final ObjectId treeId = id("9788669ad918b6fcce64af8882fc9a81cb6aba67");
		final String authorName = "A U. Thor";
		final String authorEmail = "a_u_thor@example.com";
		final int authorTime = 1218123387;
		final String authorTimeZone = "+0700";

		final String committerName = "C O. Miter";
		final String committerEmail = "comiter@example.com";
		final int committerTime = 1218123390;
		final String committerTimeZone = "-0500";
		final StringBuilder body = new StringBuilder();

		body.append("tree ");
		body.append(treeId.name());
		body.append("\n");

		body.append("author ");
		body.append(authorName);
		body.append(" <");
		body.append(authorEmail);
		body.append("> ");
		body.append(authorTime);
		body.append(" ");
		body.append(authorTimeZone);
		body.append(" \n");

		body.append("committer ");
		body.append(committerName);
		body.append(" <");
		body.append(committerEmail);
		body.append("> ");
		body.append(committerTime);
		body.append(" ");
		body.append(committerTimeZone);
		body.append("\n");

		body.append("\n");

		final RevCommit c;

		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		assertNull(c.getTree());
		assertNull(c.getParents());

		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, body.toString().getBytes(UTF_8));
			assertNotNull(c.getTree());
			assertEquals(treeId, c.getTree().getId());
			assertSame(rw.lookupTree(treeId), c.getTree());
		}
		assertNotNull(c.getParents());
		assertEquals(0, c.getParentCount());
		assertEquals("", c.getFullMessage());

		final PersonIdent cAuthor = c.getAuthorIdent();
		assertNotNull(cAuthor);
		assertEquals(authorName, cAuthor.getName());
		assertEquals(authorEmail, cAuthor.getEmailAddress());
		assertEquals(Instant.ofEpochSecond(authorTime),
				cAuthor.getWhenAsInstant());
		assertEquals(ZoneId.of(authorTimeZone), cAuthor.getZoneId());

		final PersonIdent cCommitter = c.getCommitterIdent();
		assertNotNull(cCommitter);
		assertEquals(committerName, cCommitter.getName());
		assertEquals(committerEmail, cCommitter.getEmailAddress());
		assertEquals(Instant.ofEpochSecond(committerTime),
				cCommitter.getWhenAsInstant());
		assertEquals(ZoneId.of(committerTimeZone), cCommitter.getZoneId());
	}

	private RevCommit create(String msg) throws Exception {
		final StringBuilder b = new StringBuilder();
		b.append("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n");
		b.append("author A U. Thor <a_u_thor@example.com> 1218123387 +0700\n");
		b.append("committer C O. Miter <c@example.com> 1218123390 -0500\n");
		b.append("\n");
		b.append(msg);

		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toString().getBytes(UTF_8));
			return c;
		}
	}

	@Test
	public void testParse_WeirdHeaderOnlyCommit() throws Exception {
		final StringBuilder b = new StringBuilder();
		b.append("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n");
		b.append("author A U. Thor <a_u_thor@example.com> 1218123387 +0700\n");
		b.append("committer C O. Miter <c@example.com> 1218123390 -0500\n");

		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toString().getBytes(UTF_8));
		}
		assertEquals("", c.getFullMessage());
		assertEquals("", c.getShortMessage());
	}

	@Test
	public void testParse_incompleteAuthorAndCommitter() throws Exception {
		final StringBuilder b = new StringBuilder();
		b.append("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n");
		b.append("author <a_u_thor@example.com> 1218123387 +0700\n");
		b.append("committer <> 1218123390 -0500\n");

		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toString().getBytes(UTF_8));
		}
		assertEquals(
				new PersonIdent("", "a_u_thor@example.com",
						Instant.ofEpochMilli(1218123387000L),
						ZoneOffset.ofHoursMinutes(0, 7)),
				c.getAuthorIdent());
		assertEquals(
				new PersonIdent("", "", Instant.ofEpochMilli(1218123390000L),
						ZoneOffset.ofHoursMinutes(0, -5)),
				c.getCommitterIdent());
	}

	@Test
	public void testParse_implicit_UTF8_encoded() throws Exception {
		final ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author F\u00f6r fattare <a_u_thor@example.com> 1218123387 +0700\n"
				.getBytes(UTF_8));
		b.write("committer C O. Miter <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("Sm\u00f6rg\u00e5sbord\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("\u304d\u308c\u3044\n".getBytes(UTF_8));
		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67")); // bogus id
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}
		assertSame(UTF_8, c.getEncoding());
		assertEquals("F\u00f6r fattare", c.getAuthorIdent().getName());
		assertEquals("Sm\u00f6rg\u00e5sbord", c.getShortMessage());
		assertEquals("Sm\u00f6rg\u00e5sbord\n\n\u304d\u308c\u3044\n",
				c.getFullMessage());
	}

	@Test
	public void testParse_implicit_mixed_encoded() throws Exception {
		final ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author F\u00f6r fattare <a_u_thor@example.com> 1218123387 +0700\n"
				.getBytes(ISO_8859_1));
		b.write("committer C O. Miter <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("Sm\u00f6rg\u00e5sbord\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("\u304d\u308c\u3044\n".getBytes(UTF_8));
		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67")); // bogus id
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}
		assertSame(UTF_8, c.getEncoding());
		assertEquals("F\u00f6r fattare", c.getAuthorIdent().getName());
		assertEquals("Sm\u00f6rg\u00e5sbord", c.getShortMessage());
		assertEquals("Sm\u00f6rg\u00e5sbord\n\n\u304d\u308c\u3044\n",
				c.getFullMessage());
	}

	/**
	 * Test parsing of a commit whose encoding is given and works.
	 *
	 * @throws Exception
	 */
	@Test
	public void testParse_explicit_encoded() throws Exception {
		final ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes("EUC-JP"));
		b.write("author F\u00f6r fattare <a_u_thor@example.com> 1218123387 +0700\n"
				.getBytes("EUC-JP"));
		b.write("committer C O. Miter <c@example.com> 1218123390 -0500\n"
				.getBytes("EUC-JP"));
		b.write("encoding euc_JP\n".getBytes("EUC-JP"));
		b.write("\n".getBytes("EUC-JP"));
		b.write("\u304d\u308c\u3044\n".getBytes("EUC-JP"));
		b.write("\n".getBytes("EUC-JP"));
		b.write("Hi\n".getBytes("EUC-JP"));
		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67")); // bogus id
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}

		assertEquals("EUC-JP", c.getEncoding().name());
		assertEquals("F\u00f6r fattare", c.getAuthorIdent().getName());
		assertEquals("\u304d\u308c\u3044", c.getShortMessage());
		assertEquals("\u304d\u308c\u3044\n\nHi\n", c.getFullMessage());
	}

	/**
	 * This is a twisted case, but show what we expect here. We can revise the
	 * expectations provided this case is updated.
	 *
	 * What happens here is that an encoding us given, but data is not encoded
	 * that way (and we can detect it), so we try other encodings.
	 *
	 * @throws Exception
	 */
	@Test
	public void testParse_explicit_bad_encoded() throws Exception {
		final ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author F\u00f6r fattare <a_u_thor@example.com> 1218123387 +0700\n"
				.getBytes(ISO_8859_1));
		b.write("committer C O. Miter <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("encoding EUC-JP\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("\u304d\u308c\u3044\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("Hi\n".getBytes(UTF_8));
		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67")); // bogus id
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}

		assertEquals("EUC-JP", c.getEncoding().name());
		assertEquals("F\u00f6r fattare", c.getAuthorIdent().getName());
		assertEquals("\u304d\u308c\u3044", c.getShortMessage());
		assertEquals("\u304d\u308c\u3044\n\nHi\n", c.getFullMessage());
	}

	/**
	 * This is a twisted case too, but show what we expect here. We can revise
	 * the expectations provided this case is updated.
	 *
	 * What happens here is that an encoding us given, but data is not encoded
	 * that way (and we can detect it), so we try other encodings. Here data
	 * could actually be decoded in the stated encoding, but we override using
	 * UTF-8.
	 *
	 * @throws Exception
	 */
	@Test
	public void testParse_explicit_bad_encoded2() throws Exception {
		final ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author F\u00f6r fattare <a_u_thor@example.com> 1218123387 +0700\n"
				.getBytes(UTF_8));
		b.write("committer C O. Miter <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("encoding ISO-8859-1\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("\u304d\u308c\u3044\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("Hi\n".getBytes(UTF_8));
		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67")); // bogus id
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}

		assertEquals("ISO-8859-1", c.getEncoding().name());
		assertEquals("F\u00f6r fattare", c.getAuthorIdent().getName());
		assertEquals("\u304d\u308c\u3044", c.getShortMessage());
		assertEquals("\u304d\u308c\u3044\n\nHi\n", c.getFullMessage());
	}

	@Test
	public void testParse_incorrectUtf8Name() throws Exception {
		ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author au <a@example.com> 1218123387 +0700\n".getBytes(UTF_8));
		b.write("committer co <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("encoding 'utf8'\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("Sm\u00f6rg\u00e5sbord\n".getBytes(UTF_8));

		RevCommit c = new RevCommit(
				id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}
		assertEquals("'utf8'", c.getEncodingName());
		assertEquals("Sm\u00f6rg\u00e5sbord\n", c.getFullMessage());

		try {
			c.getEncoding();
			fail("Expected " + IllegalCharsetNameException.class);
		} catch (IllegalCharsetNameException badName) {
			assertEquals("'utf8'", badName.getMessage());
		}
	}

	@Test
	public void testParse_illegalEncoding() throws Exception {
		ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author au <a@example.com> 1218123387 +0700\n".getBytes(UTF_8));
		b.write("committer co <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("encoding utf-8logoutputencoding=gbk\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("message\n".getBytes(UTF_8));

		RevCommit c = new RevCommit(
				id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}
		assertEquals("utf-8logoutputencoding=gbk", c.getEncodingName());
		assertEquals("message\n", c.getFullMessage());
		assertEquals("message", c.getShortMessage());
		assertTrue(c.getFooterLines().isEmpty());
		assertEquals("au", c.getAuthorIdent().getName());

		try {
			c.getEncoding();
			fail("Expected " + IllegalCharsetNameException.class);
		} catch (IllegalCharsetNameException badName) {
			assertEquals("utf-8logoutputencoding=gbk", badName.getMessage());
		}
	}

	@Test
	public void testParse_unsupportedEncoding() throws Exception {
		ByteArrayOutputStream b = new ByteArrayOutputStream();
		b.write("tree 9788669ad918b6fcce64af8882fc9a81cb6aba67\n"
				.getBytes(UTF_8));
		b.write("author au <a@example.com> 1218123387 +0700\n".getBytes(UTF_8));
		b.write("committer co <c@example.com> 1218123390 -0500\n"
				.getBytes(UTF_8));
		b.write("encoding it_IT.UTF8\n".getBytes(UTF_8));
		b.write("\n".getBytes(UTF_8));
		b.write("message\n".getBytes(UTF_8));

		RevCommit c = new RevCommit(
				id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, b.toByteArray());
		}
		assertEquals("it_IT.UTF8", c.getEncodingName());
		assertEquals("message\n", c.getFullMessage());
		assertEquals("message", c.getShortMessage());
		assertTrue(c.getFooterLines().isEmpty());
		assertEquals("au", c.getAuthorIdent().getName());

		try {
			c.getEncoding();
			fail("Expected " + UnsupportedCharsetException.class);
		} catch (UnsupportedCharsetException badName) {
			assertEquals("it_IT.UTF8", badName.getMessage());
		}
	}

	@Test
	public void testParse_NoMessage() throws Exception {
		final String msg = "";
		final RevCommit c = create(msg);
		assertEquals(msg, c.getFullMessage());
		assertEquals(msg, c.getShortMessage());
		assertEquals(msg, c.getFirstMessageLine());
	}

	@Test
	public void testParse_OnlyLFMessage() throws Exception {
		final RevCommit c = create("\n");
		assertEquals("\n", c.getFullMessage());
		assertEquals("", c.getShortMessage());
		assertEquals("", c.getFirstMessageLine());
	}

	@Test
	public void testParse_ShortLineOnlyNoLF() throws Exception {
		final String shortMsg = "This is a short message.";
		final RevCommit c = create(shortMsg);
		assertEquals(shortMsg, c.getFullMessage());
		assertEquals(shortMsg, c.getShortMessage());
		assertEquals(shortMsg, c.getFirstMessageLine());
	}

	@Test
	public void testParse_ShortLineOnlyEndLF() throws Exception {
		final String shortMsg = "This is a short message.";
		final String fullMsg = shortMsg + "\n";
		final RevCommit c = create(fullMsg);
		assertEquals(fullMsg, c.getFullMessage());
		assertEquals(shortMsg, c.getShortMessage());
		assertEquals(shortMsg, c.getFirstMessageLine());
	}

	@Test
	public void testParse_ShortLineOnlyEmbeddedLF() throws Exception {
		final String fullMsg = "This is a\nshort message.";
		final String shortMsg = fullMsg.replace('\n', ' ');
		final RevCommit c = create(fullMsg);
		assertEquals(fullMsg, c.getFullMessage());
		assertEquals(shortMsg, c.getShortMessage());
		assertEquals("This is a", c.getFirstMessageLine());
	}

	@Test
	public void testParse_ShortLineOnlyEmbeddedAndEndingLF() throws Exception {
		final String fullMsg = "This is a\nshort message.\n";
		final String shortMsg = "This is a short message.";
		final RevCommit c = create(fullMsg);
		assertEquals(fullMsg, c.getFullMessage());
		assertEquals(shortMsg, c.getShortMessage());
		assertEquals("This is a", c.getFirstMessageLine());
	}

	@Test
	public void testParse_GitStyleMessage() throws Exception {
		final String shortMsg = "This fixes a bug.";
		final String body = "We do it with magic and pixie dust and stuff.\n"
				+ "\n" + "Signed-off-by: A U. Thor <author@example.com>\n";
		final String fullMsg = shortMsg + "\n" + "\n" + body;
		final RevCommit c = create(fullMsg);
		assertEquals(fullMsg, c.getFullMessage());
		assertEquals(shortMsg, c.getShortMessage());
		assertEquals(shortMsg, c.getFirstMessageLine());
	}

	@Test
	public void testParse_PublicParseMethod()
			throws UnsupportedEncodingException {
		CommitBuilder src = new CommitBuilder();
		try (ObjectInserter.Formatter fmt = new ObjectInserter.Formatter()) {
			src.setTreeId(fmt.idFor(Constants.OBJ_TREE, new byte[] {}));
		}
		src.setAuthor(author);
		src.setCommitter(committer);
		src.setMessage("Test commit\n\nThis is a test.\n");

		RevCommit p = RevCommit.parse(src.build());
		assertEquals(src.getTreeId(), p.getTree());
		assertEquals(0, p.getParentCount());
		assertEquals(author, p.getAuthorIdent());
		assertEquals(committer, p.getCommitterIdent());
		assertEquals("Test commit", p.getShortMessage());
		assertEquals("Test commit", p.getFirstMessageLine());
		assertEquals(src.getMessage(), p.getFullMessage());
	}

	@Test
	public void testParse_GitStyleMessageWithCRLF() throws Exception {
		final String shortMsgIn = "This fixes a\r\nbug.\r\n\r\n";
		final String shortMsg = "This fixes a bug.";
		final String body = "We do it with magic and pixie dust\r\nand stuff.\r\n"
				+ "\r\n\r\n"
				+ "Signed-off-by: A U. Thor <author@example.com>\r\n";
		final String fullMsg = shortMsgIn + "\r\n" + "\r\n" + body;
		final RevCommit c = create(fullMsg);
		assertEquals(fullMsg, c.getFullMessage());
		assertEquals(shortMsg, c.getShortMessage());
		assertEquals("This fixes a", c.getFirstMessageLine());
	}

	private static ObjectId id(String str) {
		return ObjectId.fromString(str);
	}

	@Test
	public void testParse_gpgSig() throws Exception {
		String commit = "tree e3a1035abd2b319bb01e57d69b0ba6cab289297e\n"
				+ "parent 54e895b87c0768d2317a2b17062e3ad9f76a8105\n"
				+ "committer A U Thor <author@xample.com 1528968566 +0200\n"
				+ "gpgsig -----BEGIN PGP SIGNATURE-----\n" + " \n"
				+ " wsBcBAABCAAQBQJbGB4pCRBK7hj4Ov3rIwAAdHIIAENrvz23867ZgqrmyPemBEZP\n"
				+ " U24B1Tlq/DWvce2buaxmbNQngKZ0pv2s8VMc11916WfTIC9EKvioatmpjduWvhqj\n"
				+ " znQTFyiMor30pyYsfrqFuQZvqBW01o8GEWqLg8zjf9Rf0R3LlOEw86aT8CdHRlm6\n"
				+ " wlb22xb8qoX4RB+LYfz7MhK5F+yLOPXZdJnAVbuyoMGRnDpwdzjL5Hj671+XJxN5\n"
				+ " SasRdhxkkfw/ZnHxaKEc4juMz8Nziz27elRwhOQqlTYoXNJnsV//wy5Losd7aKi1\n"
				+ " xXXyUpndEOmT0CIcKHrN/kbYoVL28OJaxoBuva3WYQaRrzEe3X02NMxZe9gkSqA=\n"
				+ " =TClh\n" + " -----END PGP SIGNATURE-----\n"
				+ "some other header\n\n" + "commit message";

		final RevCommit c;
		c = new RevCommit(id("9473095c4cb2f12aefe1db8a355fe3fafba42f67"));
		try (RevWalk rw = new RevWalk(db)) {
			c.parseCanonical(rw, commit.getBytes(UTF_8));
		}
		String gpgSig = new String(c.getRawGpgSignature(), UTF_8);
		assertTrue(gpgSig.startsWith("-----BEGIN"));
		assertTrue(gpgSig.endsWith("END PGP SIGNATURE-----"));
	}

	@Test
	public void testParse_NoGpgSig() throws Exception {
		final RevCommit c = create("a message");
		assertNull(c.getRawGpgSignature());
	}
}