reactive-mail-server/backend/src/main/java/com/mailserver/config/MailAdmins.java

package com.mailserver.config;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.Arrays;
import java.util.Locale;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * Who manages mailboxes (Settings → Mailboxes): {@code mailserver.admins} (comma separated), by default the first
 * mailbox — {@code mailserver.admin.email}, or admin@<first domain>. No role in the database: the list lives in
 * the configuration, so a stolen mailbox can not make itself an administrator.
 */
@Component
public class MailAdmins {

    private final Set<String> admins;

    public MailAdmins(@Value("${mailserver.admins:}") String admins,
                      @Value("${mailserver.admin.email:}") String firstMailbox,
                      MailDomains domains) {
        String list = !admins.isBlank() ? admins
                : !firstMailbox.isBlank() ? firstMailbox
                : "admin@" + domains.domains().iterator().next();
        this.admins = Arrays.stream(list.split(","))
                .map(a -> a.trim().toLowerCase(Locale.ROOT))
                .filter(a -> !a.isEmpty())
                .collect(Collectors.toUnmodifiableSet());
    }

    public boolean isAdmin(String email) {
        return email != null && admins.contains(email.toLowerCase(Locale.ROOT));
    }
}