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package org.apache.james.mailbox.store.quota;

import static org.apache.james.mailbox.store.mail.AbstractMessageMapper.UNLIMITED;

import javax.inject.Inject;

import org.apache.james.core.quota.QuotaCountUsage;
import org.apache.james.core.quota.QuotaSizeUsage;
import org.apache.james.mailbox.MailboxSession;
import org.apache.james.mailbox.model.CurrentQuotas;
import org.apache.james.mailbox.model.MessageRange;
import org.apache.james.mailbox.model.QuotaRoot;
import org.apache.james.mailbox.quota.QuotaRootResolver;
import org.apache.james.mailbox.store.MailboxSessionMapperFactory;
import org.apache.james.mailbox.store.mail.MessageMapper;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

public class CurrentQuotaCalculator {
    private static final int NO_CONCURRENCY = 1;

    private final MailboxSessionMapperFactory factory;
    private final QuotaRootResolver quotaRootResolver;

    @Inject
    public CurrentQuotaCalculator(MailboxSessionMapperFactory factory,
                                  QuotaRootResolver quotaRootResolver) {
        this.factory = factory;
        this.quotaRootResolver = quotaRootResolver;
    }

    public Mono<CurrentQuotas> recalculateCurrentQuotas(QuotaRoot quotaRoot, MailboxSession session) {
        MessageMapper mapper = factory.getMessageMapper(session);

        return Flux.from(quotaRootResolver.retrieveAssociatedMailboxes(quotaRoot, session))
            .flatMap(mailbox -> mapper.findInMailboxReactive(mailbox, MessageRange.all(), MessageMapper.FetchType.Metadata, UNLIMITED), NO_CONCURRENCY)
            .map(message -> new CurrentQuotas(QuotaCountUsage.count(1), QuotaSizeUsage.size(message.getFullContentOctets())))
            .reduce(CurrentQuotas.emptyQuotas(), CurrentQuotas::increase);
    }
}