/*
 * Copyright (C) 2008, Google Inc.
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> 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.treewalk.filter;

import java.io.IOException;

import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.treewalk.TreeWalk;

/**
 * Includes an entry only if the subfilter does not include the entry.
 */
public class NotTreeFilter extends TreeFilter {
	/**
	 * Create a filter that negates the result of another filter.
	 *
	 * @param a
	 *            filter to negate.
	 * @return a filter that does the reverse of <code>a</code>.
	 */
	public static TreeFilter create(TreeFilter a) {
		return new NotTreeFilter(a);
	}

	private final TreeFilter a;

	private NotTreeFilter(TreeFilter one) {
		a = one;
	}

	@Override
	public TreeFilter negate() {
		return a;
	}

	@Override
	public boolean include(TreeWalk walker)
			throws MissingObjectException, IncorrectObjectTypeException,
			IOException {
		return matchFilter(walker) == 0;
	}

	@Override
	public int matchFilter(TreeWalk walker)
			throws MissingObjectException, IncorrectObjectTypeException,
			IOException {
		final int r = a.matchFilter(walker);
		// switch 0 and 1, keep -1 as that defines a subpath that must be
		// traversed before a final verdict can be made.
		if (r == 0) {
			return 1;
		}
		if (r == 1) {
			return 0;
		}
		return -1;
	}

	@Override
	public boolean shouldBeRecursive() {
		return a.shouldBeRecursive();
	}

	@Override
	public TreeFilter clone() {
		final TreeFilter n = a.clone();
		return n == a ? this : new NotTreeFilter(n);
	}

	@Override
	public String toString() {
		return "NOT " + a.toString(); //$NON-NLS-1$
	}
}