/****************************************************************
 * 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.james.rrt.lib;

import java.util.Optional;

public class SeparatorUtil {
    /**
     * Returns the character used to delineate multiple addresses.
     *
     * @param targetString
     *            the string to parse
     * @return the character to tokenize on
     */
    public static String getSeparator(String targetString) {
        return mayContainComma(targetString)
            .or(() -> mayContainSemicolon(targetString))
            .or(() -> mayContainColon(targetString))
            .orElse("");
    }

    private static Optional<String> mayContainComma(String targetString) {
        return mayContain(targetString, ",");
    }

    private static Optional<String> mayContainSemicolon(String targetString) {
        return mayContain(targetString, ";");
    }

    private static Optional<String> mayContainColon(String targetString) {
        if (Mapping.Type.hasPrefix(targetString)) {
            return Optional.empty();
        }
        return Optional.of(":");
    }

    private static Optional<String> mayContain(String targetString, String expectedCharacter) {
        return Optional.of(expectedCharacter)
            .filter(targetString::contains);
    }

}
