/*
 * 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.restconf;

import com.google.common.base.Preconditions;
import java.util.Collection;
import java.util.Collections;
import org.opendaylight.controller.md.sal.common.api.data.AsyncTransaction;
import org.opendaylight.controller.md.sal.common.api.data.TransactionChain;
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.DOMMountPointService;
import org.opendaylight.controller.md.sal.dom.api.DOMRpcService;
import org.opendaylight.controller.sal.core.api.Broker.ProviderSession;
import org.opendaylight.controller.sal.core.api.Provider;
import org.opendaylight.controller.sal.core.api.model.SchemaService;
import org.opendaylight.netconf.sal.rest.api.RestConnector;
import org.opendaylight.netconf.sal.restconf.impl.RestconfDocumentedException;
import org.opendaylight.restconf.common.wrapper.services.Draft15ServicesWrapperImpl;
import org.opendaylight.restconf.handlers.DOMDataBrokerHandler;
import org.opendaylight.restconf.handlers.DOMMountPointServiceHandler;
import org.opendaylight.restconf.handlers.RpcServiceHandler;
import org.opendaylight.restconf.handlers.SchemaContextHandler;
import org.opendaylight.restconf.handlers.TransactionChainHandler;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.model.api.SchemaContextListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Provider for restconf draft15.
 *
 */
public class RestConnectorProvider implements Provider, RestConnector, AutoCloseable {

    private static final Logger LOG = LoggerFactory.getLogger(RestConnectorProvider.class);

    public static final TransactionChainListener transactionListener = new TransactionChainListener() {
        @Override
        public void onTransactionChainFailed(final TransactionChain<?, ?> chain,
                final AsyncTransaction<?, ?> transaction, final Throwable cause) {
            LOG.warn("TransactionChain({}) {} FAILED!", chain, transaction.getIdentifier(), cause);
            resetTransactionChainForAdapaters(chain);
            throw new RestconfDocumentedException("TransactionChain(" + chain + ") not committed correctly", cause);
        }

        @Override
        public void onTransactionChainSuccessful(final TransactionChain<?, ?> chain) {
            LOG.trace("TransactionChain({}) {} SUCCESSFUL", chain);
        }
    };

    private ListenerRegistration<SchemaContextListener> listenerRegistration;
    private static TransactionChainHandler transactionChainHandler;
    private static DOMDataBroker dataBroker;

    @Override
    public void onSessionInitiated(final ProviderSession session) {
        final SchemaService schemaService = Preconditions.checkNotNull(session.getService(SchemaService.class));

        final Draft15ServicesWrapperImpl wrapperServices = Draft15ServicesWrapperImpl.getInstance();

        final SchemaContextHandler schemaCtxHandler = new SchemaContextHandler();
        this.listenerRegistration = schemaService.registerSchemaContextListener(schemaCtxHandler);

        final DOMMountPointServiceHandler domMountPointServiceHandler = new DOMMountPointServiceHandler(
                session.getService(DOMMountPointService.class));

        RestConnectorProvider.dataBroker = session.getService(DOMDataBroker.class);
        final DOMDataBrokerHandler brokerHandler = new DOMDataBrokerHandler(RestConnectorProvider.dataBroker);

        RestConnectorProvider.transactionChainHandler = new TransactionChainHandler(RestConnectorProvider.dataBroker
                .createTransactionChain(RestConnectorProvider.transactionListener));

        final DOMRpcService rpcService = session.getService(DOMRpcService.class);
        final RpcServiceHandler rpcServiceHandler = new RpcServiceHandler(rpcService);

        wrapperServices.setHandlers(schemaCtxHandler, domMountPointServiceHandler,
                RestConnectorProvider.transactionChainHandler, brokerHandler, rpcServiceHandler);
    }

    /**
     * After {@link TransactionChain} failed, this updates {@link TransactionChainHandler} with new transaction chain.
     *
     * @param chain
     *            - old {@link TransactionChain}
     */
    public static void resetTransactionChainForAdapaters(final TransactionChain<?, ?> chain) {
        LOG.trace("Resetting TransactionChain({})", chain);
        chain.close();
        RestConnectorProvider.transactionChainHandler.update(
                Preconditions.checkNotNull(RestConnectorProvider.dataBroker).createTransactionChain(
                        RestConnectorProvider.transactionListener)
        );
    }

    @Override
    public Collection<ProviderFunctionality> getProviderFunctionality() {
        return Collections.emptySet();
    }

    @Override
    public void close() throws Exception {
        // close registration
        if (this.listenerRegistration != null) {
            this.listenerRegistration.close();
        }

        // close transaction chain
        if (RestConnectorProvider.transactionChainHandler != null) {
            RestConnectorProvider.transactionChainHandler.get().close();
        }
    }
}