/*
 * Copyright (C) 2010, Mathias Kinzler <mathias.kinzler@sap.com>
 * Copyright (C) 2010, 2023 Chris Aniszczyk <caniszczyk@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.api;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.jgit.api.errors.CannotDeleteCurrentBranchException;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.api.errors.NotMergedException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.ConfigConstants;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.RefUpdate.Result;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.StoredConfig;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;

/**
 * Used to delete one or several branches.
 *
 * The result of {@link #call()} is a list with the (full) names of the deleted
 * branches.
 *
 * Note that we don't have a setter corresponding to the -r option; remote
 * tracking branches are simply deleted just like local branches.
 *
 * @see <a
 *      href="http://www.kernel.org/pub/software/scm/git/docs/git-branch.html"
 *      >Git documentation about Branch</a>
 */
public class DeleteBranchCommand extends GitCommand<List<String>> {

	private final Set<String> branchNames = new HashSet<>();

	private ProgressMonitor monitor = NullProgressMonitor.INSTANCE;

	private boolean force;

	/**
	 * Constructor for DeleteBranchCommand
	 *
	 * @param repo
	 *            the {@link org.eclipse.jgit.lib.Repository}
	 */
	protected DeleteBranchCommand(Repository repo) {
		super(repo);
	}

	@Override
	public List<String> call() throws GitAPIException,
			NotMergedException, CannotDeleteCurrentBranchException {
		checkCallable();
		List<String> result = new ArrayList<>();
		Set<String> shortNames = new HashSet<>();
		if (branchNames.isEmpty()) {
			return result;
		}
		Exception error = null;
		try {
			deleteBranches(result, shortNames);
		} catch (Exception e) {
			error = e;
		}
		monitor.beginTask(JGitText.get().updatingConfig, 1);
		try {
			updateConfig(shortNames, error);
		} finally {
			monitor.update(1);
			monitor.endTask();
		}
		return result;
	}

	private void deleteBranches(List<String> result,
			Set<String> shortNames) throws GitAPIException, NotMergedException,
			CannotDeleteCurrentBranchException {
		try {
			String currentBranch = repo.getFullBranch();
			if (!force) {
				// check if the branches to be deleted
				// are all merged into the current branch
				try (RevWalk walk = new RevWalk(repo)) {
					RevCommit tip = walk
							.parseCommit(repo.resolve(Constants.HEAD));
					for (String branchName : branchNames) {
						if (branchName == null) {
							continue;
						}
						Ref currentRef = repo.findRef(branchName);
						if (currentRef == null) {
							continue;
						}
						RevCommit base = walk
								.parseCommit(repo.resolve(branchName));
						if (!walk.isMergedInto(base, tip)) {
							throw new NotMergedException();
						}
					}
				}
			}
			setCallable(false);
			monitor.start(2);
			monitor.beginTask(JGitText.get().deletingBranches,
					branchNames.size());
			try {
				for (String branchName : branchNames) {
					if (branchName == null) {
						monitor.update(1);
						continue;
					}
					Ref currentRef = repo.findRef(branchName);
					if (currentRef == null) {
						monitor.update(1);
						continue;
					}
					String fullName = currentRef.getName();
					if (fullName.equals(currentBranch)) {
						throw new CannotDeleteCurrentBranchException(
								MessageFormat.format(JGitText
										.get().cannotDeleteCheckedOutBranch,
										branchName));
					}
					RefUpdate update = repo.updateRef(fullName);
					update.setRefLogMessage("branch deleted", false); //$NON-NLS-1$
					update.setForceUpdate(true);
					Result deleteResult = update.delete();

					switch (deleteResult) {
					case IO_FAILURE:
					case LOCK_FAILURE:
					case REJECTED:
						throw new JGitInternalException(MessageFormat.format(
								JGitText.get().deleteBranchUnexpectedResult,
								deleteResult.name()));
					default:
						result.add(fullName);
						if (fullName.startsWith(Constants.R_HEADS)) {
							shortNames.add(fullName
									.substring(Constants.R_HEADS.length()));
						}
						break;
					}
					monitor.update(1);
					if (monitor.isCancelled()) {
						break;
					}
				}
			} finally {
				monitor.endTask();
			}
		} catch (IOException ioe) {
			throw new JGitInternalException(ioe.getMessage(), ioe);
		}
	}

	private void updateConfig(Set<String> shortNames, Exception error)
			throws GitAPIException {
		IOException configError = null;
		if (!shortNames.isEmpty()) {
			try {
				// Remove upstream configurations if any
				StoredConfig cfg = repo.getConfig();
				boolean changed = false;
				for (String branchName : shortNames) {
					changed |= cfg.removeSection(
							ConfigConstants.CONFIG_BRANCH_SECTION,
							branchName);
				}
				if (changed) {
					cfg.save();
				}
			} catch (IOException e) {
				configError = e;
			}
		}
		if (error == null) {
			if (configError != null) {
				throw new JGitInternalException(configError.getMessage(),
						configError);
			}
		} else if (error instanceof GitAPIException) {
			if (configError != null) {
				error.addSuppressed(configError);
			}
			throw (GitAPIException) error;
		} else if (error instanceof RuntimeException) {
			if (configError != null) {
				error.addSuppressed(configError);
			}
			throw (RuntimeException) error;
		} else {
			JGitInternalException internal = new JGitInternalException(
					error.getMessage(), error);
			if (configError != null) {
				internal.addSuppressed(configError);
			}
			throw internal;
		}
	}

	/**
	 * Set the names of the branches to delete
	 *
	 * @param branchnames
	 *            the names of the branches to delete; if not set, this will do
	 *            nothing; invalid branch names will simply be ignored
	 * @return this instance
	 */
	public DeleteBranchCommand setBranchNames(String... branchnames) {
		checkCallable();
		this.branchNames.clear();
		this.branchNames.addAll(Arrays.asList(branchnames));
		return this;
	}

	/**
	 * Sets the names of the branches to delete
	 *
	 * @param branchNames
	 *            the names of the branches to delete; if not set, this will do
	 *            nothing; invalid branch names will simply be ignored
	 * @return {@code this}
	 * @since 6.8
	 */
	public DeleteBranchCommand setBranchNames(Collection<String> branchNames) {
		checkCallable();
		this.branchNames.clear();
		this.branchNames.addAll(branchNames);
		return this;
	}

	/**
	 * Set whether to forcefully delete branches
	 *
	 * @param force
	 *            <code>true</code> corresponds to the -D option,
	 *            <code>false</code> to the -d option (default) <br>
	 *            if <code>false</code> a check will be performed whether the
	 *            branch to be deleted is already merged into the current branch
	 *            and deletion will be refused in this case
	 * @return this instance
	 */
	public DeleteBranchCommand setForce(boolean force) {
		checkCallable();
		this.force = force;
		return this;
	}

	/**
	 * Retrieves the progress monitor.
	 *
	 * @return the {@link ProgressMonitor} for the delete operation
	 * @since 6.8
	 */
	public ProgressMonitor getProgressMonitor() {
		return monitor;
	}

	/**
	 * Sets the progress monitor associated with the delete operation. By
	 * default, this is set to <code>NullProgressMonitor</code>
	 *
	 * @see NullProgressMonitor
	 * @param monitor
	 *            a {@link ProgressMonitor}
	 * @return {@code this}
	 * @since 6.8
	 */
	public DeleteBranchCommand setProgressMonitor(ProgressMonitor monitor) {
		checkCallable();
		if (monitor == null) {
			monitor = NullProgressMonitor.INSTANCE;
		}
		this.monitor = monitor;
		return this;
	}

}