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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
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package org.apache.james.mailbox.store.mail;

import org.apache.james.mailbox.ModSeq;
import org.apache.james.mailbox.exception.MailboxException;
import org.apache.james.mailbox.model.Mailbox;
import org.apache.james.mailbox.model.MailboxId;

import reactor.core.publisher.Mono;

/**
 * Take care of provide mod-seqences for a given {@link Mailbox}. Be aware that implementations
 * need to be thread-safe!
 */
public interface ModSeqProvider {

    /**
     * Return the next mod-sequence which can be used for the {@link Mailbox}.
     * Its important that the returned mod-sequence is higher then the last used and that the next call of this method does return a higher
     * one. 
     * 
     * The first mod-seq must be >= 1
     */
    ModSeq nextModSeq(Mailbox mailbox) throws MailboxException;

    /**
     * Return the next mod-sequence which can be used for the {@link Mailbox}.
     * Its important that the returned mod-sequence is higher then the last used and that the next call of this method does return a higher
     * one. 
     * 
     * The first mod-seq must be >= 1
     */
    ModSeq nextModSeq(MailboxId mailboxId) throws MailboxException;

    /**
     * Return the highest mod-sequence which were used for the {@link Mailbox}
     */
    ModSeq highestModSeq(Mailbox mailbox) throws MailboxException;

    /**
     * Return the highest mod-sequence which were used for the {@link Mailbox}
     */
    ModSeq highestModSeq(MailboxId mailboxId) throws MailboxException;

    default Mono<ModSeq> nextModSeqReactive(MailboxId mailboxId) {
        return Mono.fromCallable(() -> nextModSeq(mailboxId));
    }
}
