/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.test.rest.yaml;

import java.util.regex.Pattern;

/**
 * Matches denylist patterns.
 *
 * Currently the following syntax is supported:
 *
 * <ul>
 *  <li>Exact matches, as in <code>cat.aliases/10_basic/Empty cluster</code></li>
 *  <li>Wildcard matches within the same segment of a path , as in <code>indices.get/10_basic/*allow_no_indices*</code>. This will
 *  match <code>indices.get/10_basic/allow_no_indices</code>, <code>indices.get/10_basic/allow_no_indices_at_all</code> but not
 *  <code>indices.get/10_basic/advanced/allow_no_indices</code> (contains an additional segment)</li>
 * </ul>
 *
 * Each denylist pattern is a suffix match on the path. Empty patterns are not allowed.
 */
final class DenylistedPathPatternMatcher {
    private final Pattern pattern;

    /**
     * Constructs a new <code>DenylistedPathPatternMatcher</code> instance from the provided suffix pattern.
     *
     * @param p The suffix pattern. Must be a non-empty string.
     */
    DenylistedPathPatternMatcher(String p) {
        // guard against accidentally matching everything as an empty string lead to the pattern ".*" which matches everything
        if (p == null || p.trim().isEmpty()) {
            throw new IllegalArgumentException("Empty denylist patterns are not supported");
        }
        // very simple transformation from wildcard to a proper regex
        String finalPattern = p.replaceAll("\\*", "[^/]*") // support wildcard matches (within a single path segment)
            .replaceAll("\\\\,", ",");  // restore previously escaped ',' in paths.

        // suffix match
        pattern = Pattern.compile(".*" + finalPattern);
    }

    /**
     * Checks whether the provided path matches the suffix pattern, i.e. "/foo/bar" will match the pattern "bar".
     *
     * @param path The path to match. Must not be null.
     * @return true iff this path is a suffix match.
     */
    public boolean isSuffixMatch(String path) {
        return pattern.matcher(path).matches();
    }
}
