/*
 * 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
 *
 * 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.ignite.internal.processors.cache.mvcc;

import org.apache.ignite.internal.IgniteInternalFuture;
import org.apache.ignite.internal.processors.affinity.AffinityTopologyVersion;
import org.apache.ignite.internal.processors.cache.GridCacheContext;
import org.apache.ignite.internal.processors.cache.distributed.near.GridNearTxLocal;
import org.apache.ignite.internal.util.future.GridFinishedFuture;
import org.jetbrains.annotations.NotNull;

/**
 * Simple MVCC tracker used only as an Mvcc snapshot holder.
 */
public class StaticMvccQueryTracker implements MvccQueryTracker {
    /** */
    private final MvccSnapshot snapshot;
    /** */
    private final GridCacheContext cctx;

    /**
     * @param cctx Cache context.
     * @param snapshot Mvcc snapshot.
     */
    public StaticMvccQueryTracker(GridCacheContext cctx, MvccSnapshot snapshot) {
        this.snapshot = snapshot;
        this.cctx = cctx;
    }

    /** {@inheritDoc} */
    @Override public MvccSnapshot snapshot() {
        assert snapshot != null : this;

        return snapshot;
    }

    /** {@inheritDoc} */
    @Override public GridCacheContext context() {
        return cctx;
    }

    /** {@inheritDoc} */
    @Override public AffinityTopologyVersion topologyVersion() {
        return AffinityTopologyVersion.NONE;
    }

    /** {@inheritDoc} */
    @Override public IgniteInternalFuture<MvccSnapshot> requestSnapshot() {
        return new GridFinishedFuture<>(snapshot);
    }

    /** {@inheritDoc} */
    @Override public IgniteInternalFuture<MvccSnapshot> requestSnapshot(@NotNull final AffinityTopologyVersion topVer) {
        return new GridFinishedFuture<>(snapshot);
    }

    /** {@inheritDoc} */
    @Override public void requestSnapshot(@NotNull AffinityTopologyVersion topVer, @NotNull MvccSnapshotResponseListener lsnr) {
        lsnr.onResponse(snapshot);
    }

    /** {@inheritDoc} */
    @Override public void onDone() {
        // No-op.
    }

    /** {@inheritDoc} */
    @Override public IgniteInternalFuture<Void> onDone(@NotNull GridNearTxLocal tx, boolean commit) {
        throw new UnsupportedOperationException("Operation is not supported.");
    }

    /** {@inheritDoc} */
    @Override public long onMvccCoordinatorChange(MvccCoordinator newCrd) {
        return MVCC_TRACKER_ID_NA;
    }

    /** {@inheritDoc} */
    @Override public long id() {
        return MVCC_TRACKER_ID_NA;
    }
}