/*
 * Copyright (C) 2012, IBM Corporation 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.pgm;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.io.File;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.List;

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.CheckoutConflictException;
import org.eclipse.jgit.diff.DiffEntry;
import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
import org.eclipse.jgit.lib.CLIRepositoryTestCase;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.treewalk.FileTreeIterator;
import org.eclipse.jgit.treewalk.FileTreeIterator.FileEntry;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.util.FS;
import org.eclipse.jgit.util.FileUtils;
import org.junit.Assume;
import org.junit.Test;

public class CheckoutTest extends CLIRepositoryTestCase {
	/**
	 * Executes specified git command (with arguments), captures exception and
	 * returns its message as an array of lines. Throws an AssertionError if no
	 * exception is thrown.
	 *
	 * @param command
	 *            a valid git command line, e.g. "git branch -h"
	 * @return message contained within the exception
	 */
	private String[] executeExpectingException(String command) {
		try {
			execute(command);
			throw new AssertionError("Expected Die");
		} catch (Exception e) {
			return e.getMessage().split(System.lineSeparator());
		}
	}

	@Test
	public void testCheckoutSelf() throws Exception {
		try (Git git = new Git(db)) {
			git.commit().setMessage("initial commit").call();

			assertStringArrayEquals("Already on 'master'",
					execute("git checkout master"));
		}
	}

	@Test
	public void testCheckoutBranch() throws Exception {
		try (Git git = new Git(db)) {
			git.commit().setMessage("initial commit").call();
			git.branchCreate().setName("side").call();

			assertStringArrayEquals("Switched to branch 'side'",
					execute("git checkout side"));
		}
	}

	@Test
	public void testCheckoutNewBranch() throws Exception {
		try (Git git = new Git(db)) {
			git.commit().setMessage("initial commit").call();

			assertStringArrayEquals("Switched to a new branch 'side'",
					execute("git checkout -b side"));
		}
	}

	@Test
	public void testCheckoutNonExistingBranch() throws Exception {
		assertStringArrayEquals(
				"error: pathspec 'side' did not match any file(s) known to git.",
				executeExpectingException("git checkout side"));
	}

	@Test
	public void testCheckoutNewBranchThatAlreadyExists() throws Exception {
		try (Git git = new Git(db)) {
			git.commit().setMessage("initial commit").call();

			assertStringArrayEquals(
					"fatal: A branch named 'master' already exists.",
				executeUnchecked("git checkout -b master"));
		}
	}

	@Test
	public void testCheckoutNewBranchOnBranchToBeBorn() throws Exception {
		assertStringArrayEquals("fatal: You are on a branch yet to be born",
				executeUnchecked("git checkout -b side"));
	}

	@Test
	public void testCheckoutUnresolvedHead() throws Exception {
		assertStringArrayEquals(
				"error: pathspec 'HEAD' did not match any file(s) known to git.",
				executeExpectingException("git checkout HEAD"));
	}

	@Test
	public void testCheckoutHead() throws Exception {
		try (Git git = new Git(db)) {
			git.commit().setMessage("initial commit").call();

			assertStringArrayEquals("", execute("git checkout HEAD"));
		}
	}

	@Test
	public void testCheckoutExistingBranchWithConflict() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("a", "Hello world a");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("commit file a").call();
			git.branchCreate().setName("branch_1").call();
			git.rm().addFilepattern("a").call();
			FileUtils.mkdirs(new File(db.getWorkTree(), "a"));
			writeTrashFile("a/b", "Hello world b");
			git.add().addFilepattern("a/b").call();
			git.commit().setMessage("commit folder a").call();
			git.rm().addFilepattern("a").call();
			writeTrashFile("a", "New Hello world a");
			git.add().addFilepattern(".").call();

			String[] execute = executeExpectingException(
					"git checkout branch_1");
			assertEquals(
					"error: Your local changes to the following files would be overwritten by checkout:",
					execute[0]);
			assertEquals("\ta", execute[1]);
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add file 'a' and 'b'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>modify file 'a'
	 * <li>Commit
	 * <li>Delete file 'a' in the working tree
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The working tree should contain 'a' with FileMode.REGULAR_FILE after the
	 * checkout.
	 *
	 * @throws Exception
	 */
	@Test
	public void testCheckoutWithMissingWorkingTreeFile() throws Exception {
		try (Git git = new Git(db)) {
			File fileA = writeTrashFile("a", "Hello world a");
			writeTrashFile("b", "Hello world b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add files a & b").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			writeTrashFile("a", "b");
			git.add().addFilepattern("a").call();
			git.commit().setMessage("modify file a").call();

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());

			FileUtils.delete(fileA);

			git.checkout().setName(branch_1.getName()).call();

			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
					db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());
			assertEquals("Hello world a", read(fileA));
		}
	}

	@Test
	public void testCheckoutOrphan() throws Exception {
		try (Git git = new Git(db)) {
			git.commit().setMessage("initial commit").call();

			assertStringArrayEquals("Switched to a new branch 'new_branch'",
					execute("git checkout --orphan new_branch"));
			assertEquals("refs/heads/new_branch",
					db.exactRef("HEAD").getTarget().getName());
			RevCommit commit = git.commit().setMessage("orphan commit").call();
			assertEquals(0, commit.getParentCount());
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add file 'b'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Add folder 'a'
	 * <li>Commit
	 * <li>Replace folder 'a' by file 'a' in the working tree
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The checkout has to delete folder but the workingtree contains a dirty
	 * file at this path. The checkout should fail like in native git.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestMissingThenFolderWithFileInWorkingTree()
			throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("b", "Hello world b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add file b").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			File folderA = new File(db.getWorkTree(), "a");
			FileUtils.mkdirs(folderA);
			writeTrashFile("a/c", "Hello world c");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add folder a").call();

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.TREE, entry.getMode());

			FileUtils.delete(folderA, FileUtils.RECURSIVE);
			writeTrashFile("a", "b");

			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
					db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());

			try {
				git.checkout().setName(branch_1.getName()).call();
				fail("Don't get the expected conflict");
			} catch (CheckoutConflictException e) {
				assertEquals("[a]", e.getConflictingPaths().toString());
				entry = new FileTreeIterator.FileEntry(
						new File(db.getWorkTree(), "a"), db.getFS());
				assertEquals(FileMode.REGULAR_FILE, entry.getMode());
			}
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add file 'a'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Replace file 'a' by folder 'a'
	 * <li>Commit
	 * <li>Delete folder 'a' in the working tree
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The working tree should contain 'a' with FileMode.REGULAR_FILE after the
	 * checkout.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestFolderWithMissingInWorkingTree() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("b", "Hello world b");
			writeTrashFile("a", "b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add file b & file a").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			git.rm().addFilepattern("a").call();
			File folderA = new File(db.getWorkTree(), "a");
			FileUtils.mkdirs(folderA);
			writeTrashFile("a/c", "Hello world c");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add folder a").call();

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.TREE, entry.getMode());

			FileUtils.delete(folderA, FileUtils.RECURSIVE);

			git.checkout().setName(branch_1.getName()).call();

			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
					db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add file 'a'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Delete file 'a'
	 * <li>Commit
	 * <li>Add folder 'a' in the working tree
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The checkout command should raise an error. The conflicting paths are 'a'
	 * and 'a/c'.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestMissingWithFolderInWorkingTree() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("b", "Hello world b");
			writeTrashFile("a", "b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add file b & file a").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			git.rm().addFilepattern("a").call();
			git.commit().setMessage("delete file a").call();

			FileUtils.mkdirs(new File(db.getWorkTree(), "a"));
			writeTrashFile("a/c", "Hello world c");

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.TREE, entry.getMode());

			CheckoutConflictException exception = null;
			try {
				git.checkout().setName(branch_1.getName()).call();
			} catch (CheckoutConflictException e) {
				exception = e;
			}
			assertNotNull(exception);
			assertEquals(2, exception.getConflictingPaths().size());
			assertEquals("a", exception.getConflictingPaths().get(0));
			assertEquals("a/c", exception.getConflictingPaths().get(1));
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add folder 'a'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Delete folder 'a'
	 * <li>Commit
	 * <li>Add file 'a' in the working tree
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The checkout command should raise an error. The conflicting path is 'a'.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestFolderThenMissingWithFileInWorkingTree()
			throws Exception {
		try (Git git = new Git(db)) {
			FileUtils.mkdirs(new File(db.getWorkTree(), "a"));
			writeTrashFile("a/c", "Hello world c");
			writeTrashFile("b", "Hello world b");
			git.add().addFilepattern(".").call();
			RevCommit commit1 = git.commit().setMessage("add folder a & file b")
					.call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			git.rm().addFilepattern("a").call();
			RevCommit commit2 = git.commit().setMessage("delete folder a").call();

			TreeWalk tw = new TreeWalk(db);
			tw.addTree(commit1.getTree());
			tw.addTree(commit2.getTree());
			List<DiffEntry> scan = DiffEntry.scan(tw);
			assertEquals(1, scan.size());
			assertEquals(FileMode.MISSING, scan.get(0).getNewMode());
			assertEquals(FileMode.TREE, scan.get(0).getOldMode());

			writeTrashFile("a", "b");

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());

			CheckoutConflictException exception = null;
			try {
				git.checkout().setName(branch_1.getName()).call();
			} catch (CheckoutConflictException e) {
				exception = e;
			}
			assertNotNull(exception);
			assertEquals(1, exception.getConflictingPaths().size());
			assertEquals("a", exception.getConflictingPaths().get(0));
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add folder 'a'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Replace folder 'a'by file 'a'
	 * <li>Commit
	 * <li>Delete file 'a' in the working tree
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The working tree should contain 'a' with FileMode.TREE after the
	 * checkout.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestFolderThenFileWithMissingInWorkingTree()
			throws Exception {
		try (Git git = new Git(db)) {
			FileUtils.mkdirs(new File(db.getWorkTree(), "a"));
			writeTrashFile("a/c", "Hello world c");
			writeTrashFile("b", "Hello world b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add folder a & file b").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			git.rm().addFilepattern("a").call();
			File fileA = new File(db.getWorkTree(), "a");
			writeTrashFile("a", "b");
			git.add().addFilepattern("a").call();
			git.commit().setMessage("add file a").call();

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());

			FileUtils.delete(fileA);

			git.checkout().setName(branch_1.getName()).call();

			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
					db.getFS());
			assertEquals(FileMode.TREE, entry.getMode());
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add file 'a'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Modify file 'a'
	 * <li>Commit
	 * <li>Delete file 'a' and replace by folder 'a' in the working tree and
	 * index
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The checkout command should raise an error. The conflicting path is 'a'.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestFileThenFileWithFolderInIndex() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("a", "Hello world a");
			writeTrashFile("b", "Hello world b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add files a & b").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			writeTrashFile("a", "b");
			git.add().addFilepattern("a").call();
			git.commit().setMessage("add file a").call();

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());

			git.rm().addFilepattern("a").call();
			FileUtils.mkdirs(new File(db.getWorkTree(), "a"));
			writeTrashFile("a/c", "Hello world c");
			git.add().addFilepattern(".").call();

			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
					db.getFS());
			assertEquals(FileMode.TREE, entry.getMode());

			CheckoutConflictException exception = null;
			try {
				git.checkout().setName(branch_1.getName()).call();
			} catch (CheckoutConflictException e) {
				exception = e;
			}
			assertNotNull(exception);
			assertEquals(1, exception.getConflictingPaths().size());
			assertEquals("a", exception.getConflictingPaths().get(0));
		}
	}

	/**
	 * Steps:
	 * <ol>
	 * <li>Add file 'a'
	 * <li>Commit
	 * <li>Create branch '1'
	 * <li>Modify file 'a'
	 * <li>Commit
	 * <li>Delete file 'a' and replace by folder 'a' in the working tree and
	 * index
	 * <li>Checkout branch '1'
	 * </ol>
	 * <p>
	 * The checkout command should raise an error. The conflicting paths are 'a'
	 * and 'a/c'.
	 *
	 * @throws Exception
	 */
	@Test
	public void fileModeTestFileWithFolderInIndex() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("b", "Hello world b");
			writeTrashFile("a", "b");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("add file b & file a").call();
			Ref branch_1 = git.branchCreate().setName("branch_1").call();
			git.rm().addFilepattern("a").call();
			writeTrashFile("a", "Hello world a");
			git.add().addFilepattern("a").call();
			git.commit().setMessage("add file a").call();

			FileEntry entry = new FileTreeIterator.FileEntry(new File(
					db.getWorkTree(), "a"), db.getFS());
			assertEquals(FileMode.REGULAR_FILE, entry.getMode());

			git.rm().addFilepattern("a").call();
			FileUtils.mkdirs(new File(db.getWorkTree(), "a"));
			writeTrashFile("a/c", "Hello world c");
			git.add().addFilepattern(".").call();

			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
					db.getFS());
			assertEquals(FileMode.TREE, entry.getMode());

			CheckoutConflictException exception = null;
			try {
				git.checkout().setName(branch_1.getName()).call();
			} catch (CheckoutConflictException e) {
				exception = e;
			}
			assertNotNull(exception);
			assertEquals(1, exception.getConflictingPaths().size());
			assertEquals("a", exception.getConflictingPaths().get(0));

			// TODO: ideally we'd like to get two paths from this exception
			// assertEquals(2, exception.getConflictingPaths().size());
			// assertEquals("a", exception.getConflictingPaths().get(0));
			// assertEquals("a/c", exception.getConflictingPaths().get(1));
		}
	}

	@Test
	public void testCheckoutPath() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("a", "Hello world a");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("commit file a").call();
			git.branchCreate().setName("branch_1").call();
			git.checkout().setName("branch_1").call();
			File b = writeTrashFile("b", "Hello world b");
			git.add().addFilepattern("b").call();
			git.commit().setMessage("commit file b").call();
			File a = writeTrashFile("a", "New Hello world a");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("modified a").call();
			assertArrayEquals(new String[] { "" },
					execute("git checkout HEAD~2 -- a"));
			assertEquals("Hello world a", read(a));
			assertArrayEquals(new String[] { "* branch_1", "  master", "" },
					execute("git branch"));
			assertEquals("Hello world b", read(b));
		}
	}

	@Test
	public void testCheckoutAllPaths() throws Exception {
		try (Git git = new Git(db)) {
			writeTrashFile("a", "Hello world a");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("commit file a").call();
			git.branchCreate().setName("branch_1").call();
			git.checkout().setName("branch_1").call();
			File b = writeTrashFile("b", "Hello world b");
			git.add().addFilepattern("b").call();
			git.commit().setMessage("commit file b").call();
			File a = writeTrashFile("a", "New Hello world a");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("modified a").call();
			assertArrayEquals(new String[] { "" },
					execute("git checkout HEAD~2 -- ."));
			assertEquals("Hello world a", read(a));
			assertArrayEquals(new String[] { "* branch_1", "  master", "" },
					execute("git branch"));
			assertEquals("Hello world b", read(b));
		}
	}

	@Test
	public void testCheckoutSingleFile() throws Exception {
		try (Git git = new Git(db)) {
			File a = writeTrashFile("a", "file a");
			git.add().addFilepattern(".").call();
			git.commit().setMessage("commit file a").call();
			writeTrashFile("a", "b");
			assertEquals("b", read(a));
			assertEquals("[]", Arrays.toString(execute("git checkout -- a")));
			assertEquals("file a", read(a));
		}
	}

	@Test
	public void testCheckoutLink() throws Exception {
		Assume.assumeTrue(FS.DETECTED.supportsSymlinks());
		try (Git git = new Git(db)) {
			Path path = writeLink("a", "link_a");
			assertTrue(Files.isSymbolicLink(path));
			git.add().addFilepattern(".").call();
			git.commit().setMessage("commit link a").call();
			deleteTrashFile("a");
			writeTrashFile("a", "Hello world a");
			assertFalse(Files.isSymbolicLink(path));
			assertEquals("[]", Arrays.toString(execute("git checkout -- a")));
			assertEquals("link_a", FileUtils.readSymLink(path.toFile()));
			assertTrue(Files.isSymbolicLink(path));
		}
	}

	@Test
	public void testCheckoutForce_Bug530771() throws Exception {
		try (Git git = new Git(db)) {
			File f = writeTrashFile("a", "Hello world");
			git.add().addFilepattern("a").call();
			git.commit().setMessage("create a").call();
			writeTrashFile("a", "Goodbye world");
			assertEquals("[]",
					Arrays.toString(execute("git checkout -f HEAD")));
			assertEquals("Hello world", read(f));
			assertEquals("[a, mode:100644, content:Hello world]",
					indexState(db, LocalDiskRepositoryTestCase.CONTENT));
		}
	}
}
