/*
 * Copyright (C) 2022, Simeon Andreev <simeon.danailov.andreev@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.pgm;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.diff.DiffEntry;
import org.eclipse.jgit.lib.CLIRepositoryTestCase;
import org.eclipse.jgit.pgm.opt.CmdLineParser;
import org.eclipse.jgit.pgm.opt.SubcommandHandler;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.treewalk.FileTreeIterator;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.util.SystemReader;
import org.junit.Assume;
import org.junit.Before;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.CmdLineException;

/**
 * Base test case for the {@code difftool} and {@code mergetool} commands.
 */
public abstract class ToolTestCase extends CLIRepositoryTestCase {

	public static class GitCliJGitWrapperParser {
		@Argument(index = 0, metaVar = "metaVar_command", required = true, handler = SubcommandHandler.class)
		TextBuiltin subcommand;

		@Argument(index = 1, metaVar = "metaVar_arg")
		List<String> arguments = new ArrayList<>();
	}

	protected static final String TOOL_NAME = "some_tool";

	private static final String TEST_BRANCH_NAME = "test_branch";

	private Git git;

	@Override
	@Before
	public void setUp() throws Exception {
		super.setUp();
		git = new Git(db);
		git.commit().setMessage("initial commit").call();
		git.branchCreate().setName(TEST_BRANCH_NAME).call();
	}

	protected String[] runAndCaptureUsingInitRaw(String... args)
			throws Exception {
		InputStream inputStream = null; // no input stream
		return runAndCaptureUsingInitRaw(inputStream, args);
	}

	protected String[] runAndCaptureUsingInitRaw(
			List<String> expectedErrorOutput, String... args) throws Exception {
		InputStream inputStream = null; // no input stream
		return runAndCaptureUsingInitRaw(inputStream, expectedErrorOutput,
				args);
	}

	protected String[] runAndCaptureUsingInitRaw(InputStream inputStream,
			String... args) throws Exception {
		List<String> expectedErrorOutput = Collections.emptyList();
		return runAndCaptureUsingInitRaw(inputStream, expectedErrorOutput,
				args);
	}

	protected String[] runAndCaptureUsingInitRaw(InputStream inputStream,
			List<String> expectedErrorOutput, String... args)
			throws CmdLineException, Exception, IOException {
		CLIGitCommand.Result result = new CLIGitCommand.Result();

		GitCliJGitWrapperParser bean = new GitCliJGitWrapperParser();
		CmdLineParser clp = new CmdLineParser(bean);
		clp.parseArgument(args);

		TextBuiltin cmd = bean.subcommand;
		cmd.initRaw(db, null, inputStream, result.out, result.err);
		cmd.execute(bean.arguments.toArray(new String[bean.arguments.size()]));
		if (cmd.getOutputWriter() != null) {
			cmd.getOutputWriter().flush();
		}
		if (cmd.getErrorWriter() != null) {
			cmd.getErrorWriter().flush();
		}

		List<String> errLines = result.errLines().stream()
				.filter(l -> !l.isBlank()) // we care only about error messages
				.collect(Collectors.toList());
		assertEquals("Expected no standard error output from tool",
				expectedErrorOutput.toString(), errLines.toString());

		return result.outLines().toArray(new String[0]);
	}

	protected String[] createMergeConflict() throws Exception {
		// create files on initial branch
		git.checkout().setName(TEST_BRANCH_NAME).call();
		writeTrashFile("dir1/a", "Hello world a");
		writeTrashFile("dir2/b", "Hello world b");
		git.add().addFilepattern(".").call();
		git.commit().setMessage("files a & b added").call();
		// create another branch and change files
		git.branchCreate().setName("branch_1").call();
		git.checkout().setName("branch_1").call();
		writeTrashFile("dir1/a", "Hello world a 1");
		writeTrashFile("dir2/b", "Hello world b 1");
		git.add().addFilepattern(".").call();
		RevCommit commit1 = git.commit()
				.setMessage("files a & b modified commit 1").call();
		// checkout initial branch
		git.checkout().setName(TEST_BRANCH_NAME).call();
		// create another branch and change files
		git.branchCreate().setName("branch_2").call();
		git.checkout().setName("branch_2").call();
		writeTrashFile("dir1/a", "Hello world a 2");
		writeTrashFile("dir2/b", "Hello world b 2");
		git.add().addFilepattern(".").call();
		git.commit().setMessage("files a & b modified commit 2").call();
		// cherry-pick conflicting changes
		git.cherryPick().include(commit1).call();
		String[] conflictingFilenames = { "dir1/a", "dir2/b" };
		return conflictingFilenames;
	}

	protected String[] createDeletedConflict() throws Exception {
		// create files on initial branch
		git.checkout().setName(TEST_BRANCH_NAME).call();
		writeTrashFile("dir1/a", "Hello world a");
		writeTrashFile("dir2/b", "Hello world b");
		git.add().addFilepattern(".").call();
		git.commit().setMessage("files a & b added").call();
		// create another branch and change files
		git.branchCreate().setName("branch_1").call();
		git.checkout().setName("branch_1").call();
		writeTrashFile("dir1/a", "Hello world a 1");
		writeTrashFile("dir2/b", "Hello world b 1");
		git.add().addFilepattern(".").call();
		RevCommit commit1 = git.commit()
				.setMessage("files a & b modified commit 1").call();
		// checkout initial branch
		git.checkout().setName(TEST_BRANCH_NAME).call();
		// create another branch and change files
		git.branchCreate().setName("branch_2").call();
		git.checkout().setName("branch_2").call();
		git.rm().addFilepattern("dir1/a").call();
		git.rm().addFilepattern("dir2/b").call();
		git.commit().setMessage("files a & b deleted commit 2").call();
		// cherry-pick conflicting changes
		git.cherryPick().include(commit1).call();
		String[] conflictingFilenames = { "dir1/a", "dir2/b" };
		return conflictingFilenames;
	}

	protected String[] createUnstagedChanges() throws Exception {
		writeTrashFile("dir1/a", "Hello world a");
		writeTrashFile("dir2/b", "Hello world b");
		git.add().addFilepattern(".").call();
		git.commit().setMessage("files a & b").call();
		writeTrashFile("dir1/a", "New Hello world a");
		writeTrashFile("dir2/b", "New Hello world b");
		String[] conflictingFilenames = { "dir1/a", "dir2/b" };
		return conflictingFilenames;
	}

	protected String[] createStagedChanges() throws Exception {
		String[] conflictingFilenames = createUnstagedChanges();
		git.add().addFilepattern(".").call();
		return conflictingFilenames;
	}

	protected List<DiffEntry> getRepositoryChanges(RevCommit commit)
			throws Exception {
		TreeWalk tw = new TreeWalk(db);
		tw.addTree(commit.getTree());
		FileTreeIterator modifiedTree = new FileTreeIterator(db);
		tw.addTree(modifiedTree);
		List<DiffEntry> changes = DiffEntry.scan(tw);
		return changes;
	}

	protected Path getFullPath(String repositoryFilename) {
		Path dotGitPath = db.getDirectory().toPath();
		Path repositoryRoot = dotGitPath.getParent();
		Path repositoryFilePath = repositoryRoot.resolve(repositoryFilename);
		return repositoryFilePath;
	}

	protected static InputStream createInputStream(String[] inputLines) {
		return createInputStream(Arrays.asList(inputLines));
	}

	protected static InputStream createInputStream(List<String> inputLines) {
		String input = String.join(System.lineSeparator(), inputLines);
		InputStream inputStream = new ByteArrayInputStream(input.getBytes(UTF_8));
		return inputStream;
	}

	protected static void assertArrayOfLinesEquals(String failMessage,
			String[] expected, String[] actual) {
		assertEquals(failMessage, toString(expected), toString(actual));
	}

	protected static void assertArrayOfMatchingLines(String failMessage,
			Pattern[] expected, String[] actual) {
		assertEquals(failMessage + System.lineSeparator()
				+ "Expected and actual lines count don't match. Expected: "
				+ Arrays.asList(expected) + ", actual: "
				+ Arrays.asList(actual), expected.length, actual.length);
		int n = expected.length;
		for (int i = 0; i < n; ++i) {
			Pattern expectedPattern = expected[i];
			String actualLine = actual[i];
			Matcher matcher = expectedPattern.matcher(actualLine);
			boolean matches = matcher.matches();
			assertTrue(failMessage + System.lineSeparator() + "Line " + i + " '"
					+ actualLine + "' doesn't match expected pattern: "
					+ expectedPattern + System.lineSeparator() + "Expected: "
					+ Arrays.asList(expected) + ", actual: "
					+ Arrays.asList(actual),
					matches);
		}
	}

	protected static void assumeLinuxPlatform() {
		Assume.assumeTrue("This test can run only in Linux tests",
				SystemReader.getInstance().isLinux());
	}
}