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 * 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                 *
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 * 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.mailetcontainer;

import java.util.Arrays;
import java.util.Optional;

import javax.mail.MessagingException;

import org.apache.james.core.MailAddress;
import org.apache.james.mime4j.codec.DecodeMonitor;
import org.apache.james.mime4j.field.ContentTypeFieldImpl;
import org.apache.james.mime4j.stream.RawField;
import org.apache.mailet.Mail;
import org.apache.mailet.base.AutomaticallySentMailDetector;

public class AutomaticallySentMailDetectorImpl implements AutomaticallySentMailDetector {

    private static final String[] MAILING_LIST_HEADERS = new String[] {
            "List-Help",
            "List-Subscribe",
            "List-Unsubscribe",
            "List-Owner",
            "List-Post",
            "List-Id",
            "List-Archive" };

    @Override
    public boolean isAutomaticallySent(Mail mail) throws MessagingException {
        return !mail.hasSender() ||
            isMailingList(mail) ||
            isAutoSubmitted(mail) ||
            isMdnSentAutomatically(mail);
    }

    @Override
    public boolean isMailingList(Mail mail) throws MessagingException {
        return senderIsMailingList(mail)
            || headerIsMailingList(mail);
    }

    private boolean senderIsMailingList(Mail mail) {
        return mail.getMaybeSender()
            .asOptional()
            .map(MailAddress::getLocalPart)
            .map(localPart ->  localPart.startsWith("owner-")
                || localPart.endsWith("-request")
                || localPart.equalsIgnoreCase("MAILER-DAEMON")
                || localPart.equalsIgnoreCase("LISTSERV")
                || localPart.equalsIgnoreCase("majordomo"))
            .orElse(false);
    }

    private boolean headerIsMailingList(Mail mail) throws MessagingException {
        return mail.getMessage()
            .getMatchingHeaders(MAILING_LIST_HEADERS)
            .hasMoreElements();
    }

    @Override
    public boolean isAutoSubmitted(Mail mail) throws MessagingException {
        String[] headers = mail.getMessage().getHeader(AUTO_SUBMITTED_HEADER);
        if (headers != null) {
            return Arrays.stream(headers)
                .anyMatch(this::isAutoSubmitted);
        }
        return false;
    }

    private boolean isAutoSubmitted(String header) {
        return header.equalsIgnoreCase(AUTO_REPLIED_VALUE)
            || header.equalsIgnoreCase(AUTO_GENERATED_VALUE)
            || header.equalsIgnoreCase(AUTO_NOTIFIED_VALUE);
    }

    @Override
    public boolean isMdnSentAutomatically(Mail mail) throws MessagingException {
        return Optional.ofNullable(mail.getMessage().getContentType())
            .map(field -> ContentTypeFieldImpl.PARSER.parse(new RawField("Content-Type", field), DecodeMonitor.SILENT))
            .map(field -> field.getMimeType())
            .stream()
            .anyMatch("multipart/report"::equals);
    }
}
