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 * to you under the Apache License, Version 2.0 (the            *
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package org.apache.james.mailbox.cassandra.mail;

import static com.datastax.driver.core.querybuilder.QueryBuilder.bindMarker;
import static com.datastax.driver.core.querybuilder.QueryBuilder.eq;
import static com.datastax.driver.core.querybuilder.QueryBuilder.insertInto;
import static com.datastax.driver.core.querybuilder.QueryBuilder.select;

import javax.inject.Inject;

import org.apache.james.backends.cassandra.utils.CassandraAsyncExecutor;
import org.apache.james.backends.cassandra.utils.CassandraUtils;
import org.apache.james.mailbox.MessageUid;
import org.apache.james.mailbox.cassandra.ids.CassandraId;
import org.apache.james.mailbox.cassandra.table.CassandraMailboxRecentsTable;

import com.datastax.driver.core.BoundStatement;
import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.querybuilder.QueryBuilder;
import com.google.common.annotations.VisibleForTesting;

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

public class CassandraMailboxRecentsDAO {

    private final CassandraAsyncExecutor cassandraAsyncExecutor;
    private final PreparedStatement readStatement;
    private final PreparedStatement deleteStatement;
    private final PreparedStatement deleteAllStatement;
    private final PreparedStatement addStatement;
    private CassandraUtils cassandraUtils;

    @Inject
    public CassandraMailboxRecentsDAO(Session session, CassandraUtils cassandraUtils) {
        cassandraAsyncExecutor = new CassandraAsyncExecutor(session);
        readStatement = createReadStatement(session);
        deleteStatement = createDeleteStatement(session);
        deleteAllStatement = createDeleteAllStatement(session);
        addStatement = createAddStatement(session);
        this.cassandraUtils = cassandraUtils;
    }

    @VisibleForTesting
    public CassandraMailboxRecentsDAO(Session session) {
        this(session, CassandraUtils.WITH_DEFAULT_CONFIGURATION);
    }

    private PreparedStatement createReadStatement(Session session) {
        return session.prepare(
            select(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID)
                .from(CassandraMailboxRecentsTable.TABLE_NAME)
                .where(eq(CassandraMailboxRecentsTable.MAILBOX_ID, bindMarker(CassandraMailboxRecentsTable.MAILBOX_ID))));
    }

    private PreparedStatement createDeleteStatement(Session session) {
        return session.prepare(
            QueryBuilder.delete()
                .from(CassandraMailboxRecentsTable.TABLE_NAME)
                .where(eq(CassandraMailboxRecentsTable.MAILBOX_ID, bindMarker(CassandraMailboxRecentsTable.MAILBOX_ID)))
                .and(eq(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID, bindMarker(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID))));
    }

    private PreparedStatement createDeleteAllStatement(Session session) {
        return session.prepare(
            QueryBuilder.delete()
                .from(CassandraMailboxRecentsTable.TABLE_NAME)
                .where(eq(CassandraMailboxRecentsTable.MAILBOX_ID, bindMarker(CassandraMailboxRecentsTable.MAILBOX_ID))));
    }

    private PreparedStatement createAddStatement(Session session) {
        return session.prepare(
            insertInto(CassandraMailboxRecentsTable.TABLE_NAME)
                .value(CassandraMailboxRecentsTable.MAILBOX_ID, bindMarker(CassandraMailboxRecentsTable.MAILBOX_ID))
                .value(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID, bindMarker(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID)));
    }

    public Flux<MessageUid> getRecentMessageUidsInMailbox(CassandraId mailboxId) {
        return cassandraAsyncExecutor.execute(bindWithMailbox(mailboxId, readStatement))
            .flatMapMany(cassandraUtils::convertToFlux)
            .map(row -> row.getLong(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID))
            .map(MessageUid::of);
    }

    private BoundStatement bindWithMailbox(CassandraId mailboxId, PreparedStatement statement) {
        return statement.bind()
            .setUUID(CassandraMailboxRecentsTable.MAILBOX_ID, mailboxId.asUuid());
    }

    public Mono<Void> removeFromRecent(CassandraId mailboxId, MessageUid messageUid) {
        return cassandraAsyncExecutor.executeVoid(deleteStatement.bind()
            .setUUID(CassandraMailboxRecentsTable.MAILBOX_ID, mailboxId.asUuid())
            .setLong(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID, messageUid.asLong()));
    }

    public Mono<Void> delete(CassandraId mailboxId) {
        return cassandraAsyncExecutor.executeVoid(deleteAllStatement.bind()
            .setUUID(CassandraMailboxRecentsTable.MAILBOX_ID, mailboxId.asUuid()));
    }

    public Mono<Void> addToRecent(CassandraId mailboxId, MessageUid messageUid) {
        return cassandraAsyncExecutor.executeVoid(addStatement.bind()
            .setUUID(CassandraMailboxRecentsTable.MAILBOX_ID, mailboxId.asUuid())
            .setLong(CassandraMailboxRecentsTable.RECENT_MESSAGE_UID, messageUid.asLong()));
    }
}
