/*
 * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */

package org.opendaylight.controller.md.sal.dom.broker.impl.legacy.sharded.adapter;

import static com.google.common.base.Preconditions.checkNotNull;

import java.util.Collections;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import javax.annotation.Nonnull;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.TransactionChainListener;
import org.opendaylight.controller.md.sal.dom.api.DOMDataBroker;
import org.opendaylight.controller.md.sal.dom.api.DOMDataBrokerExtension;
import org.opendaylight.controller.md.sal.dom.api.DOMDataChangeListener;
import org.opendaylight.controller.md.sal.dom.api.DOMDataReadOnlyTransaction;
import org.opendaylight.controller.md.sal.dom.api.DOMDataReadWriteTransaction;
import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
import org.opendaylight.controller.md.sal.dom.api.DOMTransactionChain;
import org.opendaylight.controller.sal.core.api.model.SchemaService;
import org.opendaylight.mdsal.dom.broker.ShardedDOMDataBrokerAdapter;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;


/**
 * DOMDataBroker implementation that forwards calls to {@link org.opendaylight.mdsal.dom.broker.ShardedDOMDataBrokerAdapter},
 * which in turn translates calls to shard aware implementation of {@link org.opendaylight.mdsal.dom.api.DOMDataTreeService}
 * <p>
 * The incompatibility between first and latter APIs, puts restriction on {@link DOMDataReadWriteTransaction}
 * and {@link DOMDataReadOnlyTransaction} provided by this data broker. See {@link ShardedDOMDataBrokerDelegatingReadWriteTransaction}
 * and {@link ShardedDOMDataBrokerDelegatingReadTransaction} respectively.
 */
// FIXME try to refactor some of the implementation to abstract class for better reusability
public class LegacyShardedDOMDataBrokerAdapter implements DOMDataBroker {

    private final org.opendaylight.mdsal.dom.api.DOMDataBroker delegateDataBroker;
    private final SchemaService schemaService;
    private final AtomicLong txNum = new AtomicLong();
    private final AtomicLong chainNum = new AtomicLong();

    public LegacyShardedDOMDataBrokerAdapter(final ShardedDOMDataBrokerAdapter delegateDataBroker,
                                             final SchemaService schemaService) {
        this.delegateDataBroker = checkNotNull(delegateDataBroker);
        this.schemaService = checkNotNull(schemaService);
    }

    @Override
    public DOMDataReadOnlyTransaction newReadOnlyTransaction() {
        return new ShardedDOMDataBrokerDelegatingReadTransaction(newTransactionIdentifier(),
                delegateDataBroker.newReadOnlyTransaction());
    }

    @Override
    public DOMDataReadWriteTransaction newReadWriteTransaction() {
        return new ShardedDOMDataBrokerDelegatingReadWriteTransaction(newTransactionIdentifier(), schemaService.getGlobalContext(),
                newReadOnlyTransaction(), newWriteOnlyTransaction());
    }

    @Override
    public DOMDataWriteTransaction newWriteOnlyTransaction() {
        return new ShardedDOMDataBrokerDelegatingWriteTransaction(newTransactionIdentifier(),
                delegateDataBroker.newWriteOnlyTransaction());
    }

    @Override
    public ListenerRegistration<DOMDataChangeListener> registerDataChangeListener(final LogicalDatastoreType store,
                                                                                  final YangInstanceIdentifier path,
                                                                                  final DOMDataChangeListener listener,
                                                                                  final DataChangeScope triggeringScope) {
        throw new UnsupportedOperationException("Registering data change listeners is not supported in " +
                "md-sal forwarding data broker");

    }

    @Override
    public DOMTransactionChain createTransactionChain(final TransactionChainListener listener) {
        return new ShardedDOMDataBrokerDelegatingTransactionChain(chainNum.getAndIncrement(), schemaService.getGlobalContext(),
                delegateDataBroker, listener);
    }

    @Nonnull
    @Override
    public Map<Class<? extends DOMDataBrokerExtension>, DOMDataBrokerExtension> getSupportedExtensions() {
        return Collections.emptyMap();
    }

    private Object newTransactionIdentifier() {
        return "DOM-" + txNum.getAndIncrement();
    }
}