/*
 * Copyright (c) 2015 Brocade Communications 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.cluster.datastore.admin;

import akka.actor.ActorRef;
import akka.actor.Status.Success;
import akka.dispatch.OnComplete;
import akka.pattern.Patterns;
import akka.util.Timeout;
import com.google.common.base.Function;
import com.google.common.base.Strings;
import com.google.common.base.Throwables;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.SettableFuture;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.AbstractMap.SimpleEntry;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.apache.commons.lang3.SerializationUtils;
import org.opendaylight.controller.cluster.access.concepts.MemberName;
import org.opendaylight.controller.cluster.datastore.DistributedDataStoreInterface;
import org.opendaylight.controller.cluster.datastore.messages.AddShardReplica;
import org.opendaylight.controller.cluster.datastore.messages.ChangeShardMembersVotingStatus;
import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshotList;
import org.opendaylight.controller.cluster.datastore.messages.FlipShardMembersVotingStatus;
import org.opendaylight.controller.cluster.datastore.messages.RemoveShardReplica;
import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
import org.opendaylight.controller.cluster.raft.client.messages.GetSnapshot;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.AddReplicasForAllShardsOutput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.AddReplicasForAllShardsOutputBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.AddShardReplicaInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.BackupDatastoreInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.ChangeMemberVotingStatesForAllShardsInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.ChangeMemberVotingStatesForAllShardsOutput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.ChangeMemberVotingStatesForAllShardsOutputBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.ChangeMemberVotingStatesForShardInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.ClusterAdminService;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.DataStoreType;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.FlipMemberVotingStatesForAllShardsOutput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.FlipMemberVotingStatesForAllShardsOutputBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.RemoveAllShardReplicasInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.RemoveAllShardReplicasOutput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.RemoveAllShardReplicasOutputBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.RemoveShardReplicaInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.member.voting.states.input.MemberVotingState;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.shard.result.output.ShardResult;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.cluster.admin.rev151013.shard.result.output.ShardResultBuilder;
import org.opendaylight.yangtools.yang.common.RpcError.ErrorType;
import org.opendaylight.yangtools.yang.common.RpcResult;
import org.opendaylight.yangtools.yang.common.RpcResultBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Implements the yang RPCs defined in the generated ClusterAdminService interface.
 *
 * @author Thomas Pantelis
 */
public class ClusterAdminRpcService implements ClusterAdminService {
    private static final Timeout SHARD_MGR_TIMEOUT = new Timeout(1, TimeUnit.MINUTES);

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

    private final DistributedDataStoreInterface configDataStore;
    private final DistributedDataStoreInterface operDataStore;

    public ClusterAdminRpcService(DistributedDataStoreInterface configDataStore,
            DistributedDataStoreInterface operDataStore) {
        this.configDataStore = configDataStore;
        this.operDataStore = operDataStore;
    }

    @Override
    public Future<RpcResult<Void>> addShardReplica(final AddShardReplicaInput input) {
        final String shardName = input.getShardName();
        if (Strings.isNullOrEmpty(shardName)) {
            return newFailedRpcResultFuture("A valid shard name must be specified");
        }

        DataStoreType dataStoreType = input.getDataStoreType();
        if (dataStoreType == null) {
            return newFailedRpcResultFuture("A valid DataStoreType must be specified");
        }

        LOG.info("Adding replica for shard {}", shardName);

        final SettableFuture<RpcResult<Void>> returnFuture = SettableFuture.create();
        ListenableFuture<Success> future = sendMessageToShardManager(dataStoreType, new AddShardReplica(shardName));
        Futures.addCallback(future, new FutureCallback<Success>() {
            @Override
            public void onSuccess(Success success) {
                LOG.info("Successfully added replica for shard {}", shardName);
                returnFuture.set(newSuccessfulResult());
            }

            @Override
            public void onFailure(Throwable failure) {
                onMessageFailure(String.format("Failed to add replica for shard %s", shardName),
                        returnFuture, failure);
            }
        });

        return returnFuture;
    }

    @Override
    public Future<RpcResult<Void>> removeShardReplica(RemoveShardReplicaInput input) {
        final String shardName = input.getShardName();
        if (Strings.isNullOrEmpty(shardName)) {
            return newFailedRpcResultFuture("A valid shard name must be specified");
        }

        DataStoreType dataStoreType = input.getDataStoreType();
        if (dataStoreType == null) {
            return newFailedRpcResultFuture("A valid DataStoreType must be specified");
        }

        final String memberName = input.getMemberName();
        if (Strings.isNullOrEmpty(memberName)) {
            return newFailedRpcResultFuture("A valid member name must be specified");
        }

        LOG.info("Removing replica for shard {} memberName {}, datastoreType {}", shardName, memberName, dataStoreType);

        final SettableFuture<RpcResult<Void>> returnFuture = SettableFuture.create();
        ListenableFuture<Success> future = sendMessageToShardManager(dataStoreType,
                new RemoveShardReplica(shardName, MemberName.forName(memberName)));
        Futures.addCallback(future, new FutureCallback<Success>() {
            @Override
            public void onSuccess(Success success) {
                LOG.info("Successfully removed replica for shard {}", shardName);
                returnFuture.set(newSuccessfulResult());
            }

            @Override
            public void onFailure(Throwable failure) {
                onMessageFailure(String.format("Failed to remove replica for shard %s", shardName),
                        returnFuture, failure);
            }
        });

        return returnFuture;
    }

    @Override
    public Future<RpcResult<AddReplicasForAllShardsOutput>> addReplicasForAllShards() {
        LOG.info("Adding replicas for all shards");

        final List<Entry<ListenableFuture<Success>, ShardResultBuilder>> shardResultData = new ArrayList<>();
        Function<String, Object> messageSupplier = shardName -> new AddShardReplica(shardName);

        sendMessageToManagerForConfiguredShards(DataStoreType.Config, shardResultData, messageSupplier);
        sendMessageToManagerForConfiguredShards(DataStoreType.Operational, shardResultData, messageSupplier);

        return waitForShardResults(shardResultData, shardResults ->
                new AddReplicasForAllShardsOutputBuilder().setShardResult(shardResults).build(),
                "Failed to add replica");
    }


    @Override
    public Future<RpcResult<RemoveAllShardReplicasOutput>> removeAllShardReplicas(RemoveAllShardReplicasInput input) {
        LOG.info("Removing replicas for all shards");

        final String memberName = input.getMemberName();
        if (Strings.isNullOrEmpty(memberName)) {
            return newFailedRpcResultFuture("A valid member name must be specified");
        }

        final List<Entry<ListenableFuture<Success>, ShardResultBuilder>> shardResultData = new ArrayList<>();
        Function<String, Object> messageSupplier = shardName ->
                new RemoveShardReplica(shardName, MemberName.forName(memberName));

        sendMessageToManagerForConfiguredShards(DataStoreType.Config, shardResultData, messageSupplier);
        sendMessageToManagerForConfiguredShards(DataStoreType.Operational, shardResultData, messageSupplier);

        return waitForShardResults(shardResultData, shardResults ->
                new RemoveAllShardReplicasOutputBuilder().setShardResult(shardResults).build(),
        "       Failed to remove replica");
    }

    @Override
    public Future<RpcResult<Void>> changeMemberVotingStatesForShard(ChangeMemberVotingStatesForShardInput input) {
        final String shardName = input.getShardName();
        if (Strings.isNullOrEmpty(shardName)) {
            return newFailedRpcResultFuture("A valid shard name must be specified");
        }

        DataStoreType dataStoreType = input.getDataStoreType();
        if (dataStoreType == null) {
            return newFailedRpcResultFuture("A valid DataStoreType must be specified");
        }

        List<MemberVotingState> memberVotingStates = input.getMemberVotingState();
        if (memberVotingStates == null || memberVotingStates.isEmpty()) {
            return newFailedRpcResultFuture("No member voting state input was specified");
        }

        ChangeShardMembersVotingStatus changeVotingStatus = toChangeShardMembersVotingStatus(shardName,
                memberVotingStates);

        LOG.info("Change member voting states for shard {}: {}", shardName,
                changeVotingStatus.getMeberVotingStatusMap());

        final SettableFuture<RpcResult<Void>> returnFuture = SettableFuture.create();
        ListenableFuture<Success> future = sendMessageToShardManager(dataStoreType, changeVotingStatus);
        Futures.addCallback(future, new FutureCallback<Success>() {
            @Override
            public void onSuccess(Success success) {
                LOG.info("Successfully changed member voting states for shard {}", shardName);
                returnFuture.set(newSuccessfulResult());
            }

            @Override
            public void onFailure(Throwable failure) {
                onMessageFailure(String.format("Failed to change member voting states for shard %s", shardName),
                        returnFuture, failure);
            }
        });

        return returnFuture;
    }

    @Override
    public Future<RpcResult<ChangeMemberVotingStatesForAllShardsOutput>> changeMemberVotingStatesForAllShards(
            final ChangeMemberVotingStatesForAllShardsInput input) {
        List<MemberVotingState> memberVotingStates = input.getMemberVotingState();
        if (memberVotingStates == null || memberVotingStates.isEmpty()) {
            return newFailedRpcResultFuture("No member voting state input was specified");
        }

        final List<Entry<ListenableFuture<Success>, ShardResultBuilder>> shardResultData = new ArrayList<>();
        Function<String, Object> messageSupplier = shardName ->
                toChangeShardMembersVotingStatus(shardName, memberVotingStates);

        LOG.info("Change member voting states for all shards");

        sendMessageToManagerForConfiguredShards(DataStoreType.Config, shardResultData, messageSupplier);
        sendMessageToManagerForConfiguredShards(DataStoreType.Operational, shardResultData, messageSupplier);

        return waitForShardResults(shardResultData, shardResults ->
                new ChangeMemberVotingStatesForAllShardsOutputBuilder().setShardResult(shardResults).build(),
                "Failed to change member voting states");
    }

    @Override
    public Future<RpcResult<FlipMemberVotingStatesForAllShardsOutput>> flipMemberVotingStatesForAllShards() {
        final List<Entry<ListenableFuture<Success>, ShardResultBuilder>> shardResultData = new ArrayList<>();
        Function<String, Object> messageSupplier = shardName ->
                new FlipShardMembersVotingStatus(shardName);

        LOG.info("Flip member voting states for all shards");

        sendMessageToManagerForConfiguredShards(DataStoreType.Config, shardResultData, messageSupplier);
        sendMessageToManagerForConfiguredShards(DataStoreType.Operational, shardResultData, messageSupplier);

        return waitForShardResults(shardResultData, shardResults ->
                new FlipMemberVotingStatesForAllShardsOutputBuilder().setShardResult(shardResults).build(),
                "Failed to change member voting states");
    }

    @Override
    public Future<RpcResult<Void>> backupDatastore(final BackupDatastoreInput input) {
        LOG.debug("backupDatastore: {}", input);

        if (Strings.isNullOrEmpty(input.getFilePath())) {
            return newFailedRpcResultFuture("A valid file path must be specified");
        }

        final SettableFuture<RpcResult<Void>> returnFuture = SettableFuture.create();
        ListenableFuture<List<DatastoreSnapshot>> future = sendMessageToShardManagers(GetSnapshot.INSTANCE);
        Futures.addCallback(future, new FutureCallback<List<DatastoreSnapshot>>() {
            @Override
            public void onSuccess(List<DatastoreSnapshot> snapshots) {
                saveSnapshotsToFile(new DatastoreSnapshotList(snapshots), input.getFilePath(), returnFuture);
            }

            @Override
            public void onFailure(Throwable failure) {
                onDatastoreBackupFailure(input.getFilePath(), returnFuture, failure);
            }
        });

        return returnFuture;
    }

    private ChangeShardMembersVotingStatus toChangeShardMembersVotingStatus(final String shardName,
            List<MemberVotingState> memberVotingStatus) {
        Map<String, Boolean> serverVotingStatusMap = new HashMap<>();
        for (MemberVotingState memberStatus: memberVotingStatus) {
            serverVotingStatusMap.put(memberStatus.getMemberName(), memberStatus.isVoting());
        }

        ChangeShardMembersVotingStatus changeVotingStatus = new ChangeShardMembersVotingStatus(shardName,
                serverVotingStatusMap);
        return changeVotingStatus;
    }

    private static <T> SettableFuture<RpcResult<T>> waitForShardResults(
            final List<Entry<ListenableFuture<Success>, ShardResultBuilder>> shardResultData,
            final Function<List<ShardResult>, T> resultDataSupplier,
            final String failureLogMsgPrefix) {
        final SettableFuture<RpcResult<T>> returnFuture = SettableFuture.create();
        final List<ShardResult> shardResults = new ArrayList<>();
        for (final Entry<ListenableFuture<Success>, ShardResultBuilder> entry : shardResultData) {
            Futures.addCallback(entry.getKey(), new FutureCallback<Success>() {
                @Override
                public void onSuccess(Success result) {
                    synchronized (shardResults) {
                        ShardResultBuilder shardResult = entry.getValue();
                        LOG.debug("onSuccess for shard {}, type {}", shardResult.getShardName(),
                                shardResult.getDataStoreType());
                        shardResults.add(shardResult.setSucceeded(true).build());
                        checkIfComplete();
                    }
                }

                @Override
                public void onFailure(Throwable failure) {
                    synchronized (shardResults) {
                        ShardResultBuilder shardResult = entry.getValue();
                        LOG.warn("{} for shard {}, type {}", failureLogMsgPrefix, shardResult.getShardName(),
                                shardResult.getDataStoreType(), failure);
                        shardResults.add(shardResult.setSucceeded(false).setErrorMessage(
                                Throwables.getRootCause(failure).getMessage()).build());
                        checkIfComplete();
                    }
                }

                void checkIfComplete() {
                    LOG.debug("checkIfComplete: expected {}, actual {}", shardResultData.size(), shardResults.size());
                    if (shardResults.size() == shardResultData.size()) {
                        returnFuture.set(newSuccessfulResult(resultDataSupplier.apply(shardResults)));
                    }
                }
            });
        }
        return returnFuture;
    }

    private <T> void sendMessageToManagerForConfiguredShards(DataStoreType dataStoreType,
            List<Entry<ListenableFuture<T>, ShardResultBuilder>> shardResultData,
            Function<String, Object> messageSupplier) {
        ActorContext actorContext = dataStoreType == DataStoreType.Config ? configDataStore.getActorContext()
                : operDataStore.getActorContext();
        Set<String> allShardNames = actorContext.getConfiguration().getAllShardNames();

        LOG.debug("Sending message to all shards {} for data store {}", allShardNames, actorContext.getDataStoreName());

        for (String shardName: allShardNames) {
            ListenableFuture<T> future = this.<T>ask(actorContext.getShardManager(), messageSupplier.apply(shardName),
                    SHARD_MGR_TIMEOUT);
            shardResultData.add(new SimpleEntry<>(future,
                    new ShardResultBuilder().setShardName(shardName).setDataStoreType(dataStoreType)));
        }
    }

    @SuppressWarnings("unchecked")
    private <T> ListenableFuture<List<T>> sendMessageToShardManagers(Object message) {
        Timeout timeout = SHARD_MGR_TIMEOUT;
        ListenableFuture<T> configFuture = ask(configDataStore.getActorContext().getShardManager(), message, timeout);
        ListenableFuture<T> operFuture = ask(operDataStore.getActorContext().getShardManager(), message, timeout);

        return Futures.allAsList(configFuture, operFuture);
    }

    private <T> ListenableFuture<T> sendMessageToShardManager(DataStoreType dataStoreType, Object message) {
        ActorRef shardManager = dataStoreType == DataStoreType.Config
                ? configDataStore.getActorContext().getShardManager()
                        : operDataStore.getActorContext().getShardManager();
        return ask(shardManager, message, SHARD_MGR_TIMEOUT);
    }

    @SuppressWarnings("checkstyle:IllegalCatch")
    private static void saveSnapshotsToFile(DatastoreSnapshotList snapshots, String fileName,
            SettableFuture<RpcResult<Void>> returnFuture) {
        try (FileOutputStream fos = new FileOutputStream(fileName)) {
            SerializationUtils.serialize(snapshots, fos);

            returnFuture.set(newSuccessfulResult());
            LOG.info("Successfully backed up datastore to file {}", fileName);
        } catch (IOException | RuntimeException e) {
            onDatastoreBackupFailure(fileName, returnFuture, e);
        }
    }

    private static void onDatastoreBackupFailure(String fileName, SettableFuture<RpcResult<Void>> returnFuture,
            Throwable failure) {
        onMessageFailure(String.format("Failed to back up datastore to file %s", fileName), returnFuture, failure);
    }

    private static void onMessageFailure(String msg, final SettableFuture<RpcResult<Void>> returnFuture,
            Throwable failure) {
        LOG.error(msg, failure);
        returnFuture.set(ClusterAdminRpcService.<Void>newFailedRpcResultBuilder(String.format("%s: %s", msg,
                failure.getMessage())).build());
    }

    private <T> ListenableFuture<T> ask(ActorRef actor, Object message, Timeout timeout) {
        final SettableFuture<T> returnFuture = SettableFuture.create();

        @SuppressWarnings("unchecked")
        scala.concurrent.Future<T> askFuture = (scala.concurrent.Future<T>) Patterns.ask(actor, message, timeout);
        askFuture.onComplete(new OnComplete<T>() {
            @Override
            public void onComplete(Throwable failure, T resp) {
                if (failure != null) {
                    returnFuture.setException(failure);
                } else {
                    returnFuture.set(resp);
                }
            }
        }, configDataStore.getActorContext().getClientDispatcher());

        return returnFuture;
    }

    private static <T> ListenableFuture<RpcResult<T>> newFailedRpcResultFuture(String message) {
        return ClusterAdminRpcService.<T>newFailedRpcResultBuilder(message).buildFuture();
    }

    private static <T> RpcResultBuilder<T> newFailedRpcResultBuilder(String message) {
        return newFailedRpcResultBuilder(message, null);
    }

    private static <T> RpcResultBuilder<T> newFailedRpcResultBuilder(String message, Throwable cause) {
        return RpcResultBuilder.<T>failed().withError(ErrorType.RPC, message, cause);
    }

    private static RpcResult<Void> newSuccessfulResult() {
        return newSuccessfulResult((Void)null);
    }

    private static <T> RpcResult<T> newSuccessfulResult(T data) {
        return RpcResultBuilder.<T>success(data).build();
    }
}