content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF 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.
   */
  package org.apache.beam.it.mongodb;
  
  import static org.apache.beam.it.common.utils.ResourceManagerUtils.generateResourceId;
  
  import java.time.format.DateTimeFormatter;
  import java.util.regex.Pattern;
  
  /** Utilities for {@link MongoDBResourceManager} implementations. */
  final class MongoDBResourceManagerUtils {
  
    // MongoDB Database and Collection naming restrictions can be found at
    // https://www.mongodb.com/docs/manual/reference/limits/#naming-restrictions
    private static final int MAX_DATABASE_NAME_LENGTH = 63;
    private static final Pattern ILLEGAL_DATABASE_NAME_CHARS =
        Pattern.compile("[/\\\\. \"\0$]"); // i.e. [/\. "$]
    private static final String REPLACE_DATABASE_NAME_CHAR = "-";
    private static final int MIN_COLLECTION_NAME_LENGTH = 1;
    private static final int MAX_COLLECTION_NAME_LENGTH = 99;
    private static final Pattern ILLEGAL_COLLECTION_CHARS = Pattern.compile("[$\0]");
    private static final DateTimeFormatter TIME_FORMAT =
        DateTimeFormatter.ofPattern("yyyyMMdd-HHmmss-SSSSSS");
  
    private MongoDBResourceManagerUtils() {}
  
    /**
     * Generates a MongoDB database name from a given string.
     *
     * @param baseString The string to generate the name from.
     * @return The database name string.
     */
    static String generateDatabaseName(String baseString) {
      return generateResourceId(
          baseString,
          ILLEGAL_DATABASE_NAME_CHARS,
          REPLACE_DATABASE_NAME_CHAR,
          MAX_DATABASE_NAME_LENGTH,
          TIME_FORMAT);
    }
  
    /**
     * Checks whether the given collection name is valid according to MongoDB constraints.
     *
     * @param databaseName the database name associated with the collection
     * @param collectionName the collection name to check.
     * @throws IllegalArgumentException if the collection name is invalid.
     */
    static void checkValidCollectionName(String databaseName, String collectionName) {
      String fullCollectionName = databaseName + "." + collectionName;
      if (collectionName.length() < MIN_COLLECTION_NAME_LENGTH) {
        throw new IllegalArgumentException("Collection name cannot be empty.");
      }
      if (fullCollectionName.length() > MAX_COLLECTION_NAME_LENGTH) {
        throw new IllegalArgumentException(
            "Collection name "
                + fullCollectionName
                + " cannot be longer than "
                + MAX_COLLECTION_NAME_LENGTH
                + " characters, including the database name and dot.");
      }
      if (ILLEGAL_COLLECTION_CHARS.matcher(collectionName).find()) {
        throw new IllegalArgumentException(
            "Collection name "
                + collectionName
                + " is not a valid name. Only letters, numbers, hyphens, underscores and exclamation points are allowed.");
      }
      if (collectionName.charAt(0) != '_' && !Character.isLetter(collectionName.charAt(0))) {
        throw new IllegalArgumentException(
            "Collection name " + collectionName + " must start with a letter or an underscore.");
      }
      String illegalKeyword = "system.";
      if (collectionName.startsWith(illegalKeyword)) {
        throw new IllegalArgumentException(
            "Collection name "
                + collectionName
                + " cannot start with the prefix \""
                + illegalKeyword
                + "\".");
      }
    }
  }
  