/*
 * Copyright (c) 2018 Inocybe Technologies 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.netconf.topology.singleton.impl.tx;

import akka.actor.ActorRef;
import akka.dispatch.OnComplete;
import akka.pattern.AskTimeoutException;
import akka.pattern.Patterns;
import akka.util.Timeout;
import com.google.common.base.Optional;
import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.FluentFuture;
import com.google.common.util.concurrent.SettableFuture;
import java.util.Objects;
import org.eclipse.jdt.annotation.NonNull;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
import org.opendaylight.mdsal.common.api.CommitInfo;
import org.opendaylight.mdsal.common.api.MappingCheckedFuture;
import org.opendaylight.netconf.sal.connect.util.RemoteDeviceId;
import org.opendaylight.netconf.topology.singleton.impl.utils.NetconfTopologyUtils;
import org.opendaylight.netconf.topology.singleton.messages.NormalizedNodeMessage;
import org.opendaylight.netconf.topology.singleton.messages.transactions.CancelRequest;
import org.opendaylight.netconf.topology.singleton.messages.transactions.DeleteRequest;
import org.opendaylight.netconf.topology.singleton.messages.transactions.EmptyReadResponse;
import org.opendaylight.netconf.topology.singleton.messages.transactions.ExistsRequest;
import org.opendaylight.netconf.topology.singleton.messages.transactions.MergeRequest;
import org.opendaylight.netconf.topology.singleton.messages.transactions.PutRequest;
import org.opendaylight.netconf.topology.singleton.messages.transactions.ReadRequest;
import org.opendaylight.netconf.topology.singleton.messages.transactions.SubmitRequest;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import scala.concurrent.ExecutionContext;
import scala.concurrent.Future;

/**
 * ProxyTransactionFacade implementation that interfaces with an actor.
 *
 * @author Thomas Pantelis
 */
class ActorProxyTransactionFacade implements ProxyTransactionFacade {
    private static final Logger LOG = LoggerFactory.getLogger(ActorProxyTransactionFacade.class);

    private final ActorRef masterTxActor;
    private final RemoteDeviceId id;
    private final ExecutionContext executionContext;
    private final Timeout askTimeout;

    ActorProxyTransactionFacade(ActorRef masterTxActor, RemoteDeviceId id, ExecutionContext executionContext,
            Timeout askTimeout) {
        this.masterTxActor = Objects.requireNonNull(masterTxActor);
        this.id = Objects.requireNonNull(id);
        this.executionContext = Objects.requireNonNull(executionContext);
        this.askTimeout = Objects.requireNonNull(askTimeout);
    }

    @Override
    public Object getIdentifier() {
        return id;
    }

    @Override
    public boolean cancel() {
        LOG.debug("{}: Cancel via actor {}", id, masterTxActor);

        final Future<Object> future = Patterns.ask(masterTxActor, new CancelRequest(), askTimeout);

        future.onComplete(new OnComplete<Object>() {
            @Override
            public void onComplete(final Throwable failure, final Object response) {
                if (failure != null) {
                    LOG.warn("{}: Cancel failed", id, failure);
                    return;
                }

                LOG.debug("{}: Cancel succeeded", id);
            }
        }, executionContext);

        return true;
    }

    @Override
    public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(LogicalDatastoreType store,
            YangInstanceIdentifier path) {
        LOG.debug("{}: Read {} {} via actor {}", id, store, path, masterTxActor);

        final Future<Object> future = Patterns.ask(masterTxActor, new ReadRequest(store, path), askTimeout);

        final SettableFuture<Optional<NormalizedNode<?, ?>>> settableFuture = SettableFuture.create();
        future.onComplete(new OnComplete<Object>() {
            @Override
            public void onComplete(final Throwable failure, final Object response) {
                if (failure != null) {
                    LOG.debug("{}: Read {} {} failed", id, store, path, failure);
                    settableFuture.setException(processFailure(failure));
                    return;
                }

                LOG.debug("{}: Read {} {} succeeded: {}", id, store, path, response);

                if (response instanceof EmptyReadResponse) {
                    settableFuture.set(Optional.absent());
                    return;
                }

                if (response instanceof NormalizedNodeMessage) {
                    final NormalizedNodeMessage data = (NormalizedNodeMessage) response;
                    settableFuture.set(Optional.of(data.getNode()));
                }
            }
        }, executionContext);

        return MappingCheckedFuture.create(settableFuture, ReadFailedException.MAPPER);
    }

    @Override
    public CheckedFuture<Boolean, ReadFailedException> exists(LogicalDatastoreType store, YangInstanceIdentifier path) {
        LOG.debug("{}: Exists {} {} via actor {}", id, store, path, masterTxActor);

        final Future<Object> future = Patterns.ask(masterTxActor, new ExistsRequest(store, path), askTimeout);

        final SettableFuture<Boolean> settableFuture = SettableFuture.create();
        future.onComplete(new OnComplete<Object>() {
            @Override
            public void onComplete(final Throwable failure, final Object response) {
                if (failure != null) {
                    LOG.debug("{}: Exists {} {} failed", id, store, path, failure);
                    settableFuture.setException(processFailure(failure));
                    return;
                }

                LOG.debug("{}: Exists {} {} succeeded: {}", id, store, path, response);

                settableFuture.set((Boolean) response);
            }
        }, executionContext);

        return MappingCheckedFuture.create(settableFuture, ReadFailedException.MAPPER);
    }

    @Override
    public void delete(LogicalDatastoreType store, YangInstanceIdentifier path) {
        LOG.debug("{}: Delete {} {} via actor {}", id, store, path, masterTxActor);
        masterTxActor.tell(new DeleteRequest(store, path), ActorRef.noSender());
    }

    @Override
    public void put(LogicalDatastoreType store, YangInstanceIdentifier path, NormalizedNode<?, ?> data) {
        LOG.debug("{}: Put {} {} via actor {}", id, store, path, masterTxActor);
        masterTxActor.tell(new PutRequest(store, new NormalizedNodeMessage(path, data)), ActorRef.noSender());
    }

    @Override
    public void merge(LogicalDatastoreType store, YangInstanceIdentifier path, NormalizedNode<?, ?> data) {
        LOG.debug("{}: Merge {} {} via actor {}", id, store, path, masterTxActor);
        masterTxActor.tell(new MergeRequest(store, new NormalizedNodeMessage(path, data)), ActorRef.noSender());
    }

    @Override
    public @NonNull FluentFuture<? extends @NonNull CommitInfo> commit() {
        LOG.debug("{}: Commit via actor {}", id, masterTxActor);

        final Future<Object> future = Patterns.ask(masterTxActor, new SubmitRequest(), askTimeout);

        final SettableFuture<CommitInfo> settableFuture = SettableFuture.create();
        future.onComplete(new OnComplete<Object>() {
            @Override
            public void onComplete(final Throwable failure, final Object response) {
                if (failure != null) {
                    LOG.debug("{}: Commit failed", id, failure);
                    settableFuture.setException(newTransactionCommitFailedException(processFailure(failure)));
                    return;
                }

                LOG.debug("{}: Commit succeeded", id);

                settableFuture.set(CommitInfo.empty());
            }
        }, executionContext);

        return settableFuture;
    }

    private TransactionCommitFailedException newTransactionCommitFailedException(final Throwable failure) {
        return new TransactionCommitFailedException(String.format("%s: Commit of transaction failed", getIdentifier()),
                failure);
    }

    private Throwable processFailure(Throwable failure) {
        if (failure instanceof AskTimeoutException) {
            return NetconfTopologyUtils.createMasterIsDownException(id, (Exception)failure);
        }

        return failure;
    }
}