/**
 * Copyright © 2016-2018 The Thingsboard Authors
 *
 * Licensed 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.thingsboard.server.service.rpc;

import com.datastax.driver.core.utils.UUIDs;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.protobuf.InvalidProtocolBufferException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.thingsboard.rule.engine.api.RpcError;
import org.thingsboard.rule.engine.api.msg.ToDeviceActorNotificationMsg;
import org.thingsboard.server.actors.service.ActorService;
import org.thingsboard.server.common.data.DataConstants;
import org.thingsboard.server.common.data.id.DeviceId;
import org.thingsboard.server.common.data.id.TenantId;
import org.thingsboard.server.common.msg.TbMsg;
import org.thingsboard.server.common.msg.TbMsgDataType;
import org.thingsboard.server.common.msg.TbMsgMetaData;
import org.thingsboard.server.common.msg.cluster.SendToClusterMsg;
import org.thingsboard.server.common.msg.cluster.ServerAddress;
import org.thingsboard.server.common.msg.core.ToServerRpcResponseMsg;
import org.thingsboard.server.common.msg.rpc.ToDeviceRpcRequest;
import org.thingsboard.server.common.msg.system.ServiceToRuleEngineMsg;
import org.thingsboard.server.gen.cluster.ClusterAPIProtos;
import org.thingsboard.server.service.cluster.routing.ClusterRoutingService;
import org.thingsboard.server.service.cluster.rpc.ClusterRpcService;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;

/**
 * Created by ashvayka on 27.03.18.
 */
@Service
@Slf4j
public class DefaultDeviceRpcService implements DeviceRpcService {

    private static final ObjectMapper json = new ObjectMapper();

    @Autowired
    private ClusterRoutingService routingService;

    @Autowired
    private ClusterRpcService rpcService;

    @Autowired
    private ActorService actorService;

    private ScheduledExecutorService rpcCallBackExecutor;

    private final ConcurrentMap<UUID, Consumer<FromDeviceRpcResponse>> localToRuleEngineRpcRequests = new ConcurrentHashMap<>();
    private final ConcurrentMap<UUID, Consumer<FromDeviceRpcResponse>> localToDeviceRpcRequests = new ConcurrentHashMap<>();

    @PostConstruct
    public void initExecutor() {
        rpcCallBackExecutor = Executors.newSingleThreadScheduledExecutor();
    }

    @PreDestroy
    public void shutdownExecutor() {
        if (rpcCallBackExecutor != null) {
            rpcCallBackExecutor.shutdownNow();
        }
    }

    @Override
    public void processRestAPIRpcRequestToRuleEngine(ToDeviceRpcRequest request, Consumer<FromDeviceRpcResponse> responseConsumer) {
        log.trace("[{}] Processing local rpc call to rule engine [{}]", request.getTenantId(), request.getDeviceId());
        UUID requestId = request.getId();
        localToRuleEngineRpcRequests.put(requestId, responseConsumer);
        sendRpcRequestToRuleEngine(request);
        scheduleTimeout(request, requestId, localToRuleEngineRpcRequests);
    }

    @Override
    public void processRestAPIRpcResponseFromRuleEngine(FromDeviceRpcResponse response) {
        UUID requestId = response.getId();
        Consumer<FromDeviceRpcResponse> consumer = localToRuleEngineRpcRequests.remove(requestId);
        if (consumer != null) {
            consumer.accept(response);
        } else {
            log.trace("[{}] Unknown or stale rpc response received [{}]", requestId, response);
        }
    }

    @Override
    public void processRpcRequestToDevice(ToDeviceRpcRequest request, Consumer<FromDeviceRpcResponse> responseConsumer) {
        log.trace("[{}] Processing local rpc call to device [{}]", request.getTenantId(), request.getDeviceId());
        UUID requestId = request.getId();
        localToDeviceRpcRequests.put(requestId, responseConsumer);
        sendRpcRequestToDevice(request);
        scheduleTimeout(request, requestId, localToDeviceRpcRequests);
    }

    @Override
    public void processRpcResponseFromDevice(FromDeviceRpcResponse response) {
        log.trace("[{}] response to request: [{}]", this.hashCode(), response.getId());
        if (routingService.getCurrentServer().equals(response.getServerAddress())) {
            UUID requestId = response.getId();
            Consumer<FromDeviceRpcResponse> consumer = localToDeviceRpcRequests.remove(requestId);
            if (consumer != null) {
                consumer.accept(response);
            } else {
                log.trace("[{}] Unknown or stale rpc response received [{}]", requestId, response);
            }
        } else {
            ClusterAPIProtos.FromDeviceRPCResponseProto.Builder builder = ClusterAPIProtos.FromDeviceRPCResponseProto.newBuilder();
            builder.setRequestIdMSB(response.getId().getMostSignificantBits());
            builder.setRequestIdLSB(response.getId().getLeastSignificantBits());
            response.getResponse().ifPresent(builder::setResponse);
            if (response.getError().isPresent()) {
                builder.setError(response.getError().get().ordinal());
            } else {
                builder.setError(-1);
            }
            rpcService.tell(response.getServerAddress(), ClusterAPIProtos.MessageType.CLUSTER_RPC_FROM_DEVICE_RESPONSE_MESSAGE, builder.build().toByteArray());
        }
    }

    @Override
    public void processRemoteResponseFromDevice(ServerAddress serverAddress, byte[] data) {
        ClusterAPIProtos.FromDeviceRPCResponseProto proto;
        try {
            proto = ClusterAPIProtos.FromDeviceRPCResponseProto.parseFrom(data);
        } catch (InvalidProtocolBufferException e) {
            throw new RuntimeException(e);
        }
        RpcError error = proto.getError() > 0 ? RpcError.values()[proto.getError()] : null;
        FromDeviceRpcResponse response = new FromDeviceRpcResponse(new UUID(proto.getRequestIdMSB(), proto.getRequestIdLSB()), routingService.getCurrentServer(),
                proto.getResponse(), error);
        processRpcResponseFromDevice(response);
    }

    @Override
    public void sendRpcReplyToDevice(TenantId tenantId, DeviceId deviceId, int requestId, String body) {
        ToServerRpcResponseActorMsg rpcMsg = new ToServerRpcResponseActorMsg(tenantId, deviceId, new ToServerRpcResponseMsg(requestId, body));
        forward(deviceId, rpcMsg);
    }

    private void sendRpcRequestToRuleEngine(ToDeviceRpcRequest msg) {
        ObjectNode entityNode = json.createObjectNode();
        TbMsgMetaData metaData = new TbMsgMetaData();
        metaData.putValue("requestUUID", msg.getId().toString());
        metaData.putValue("expirationTime", Long.toString(msg.getExpirationTime()));
        metaData.putValue("oneway", Boolean.toString(msg.isOneway()));

        entityNode.put("method", msg.getBody().getMethod());
        entityNode.put("params", msg.getBody().getParams());

        try {
            TbMsg tbMsg = new TbMsg(UUIDs.timeBased(), DataConstants.RPC_CALL_FROM_SERVER_TO_DEVICE, msg.getDeviceId(), metaData, TbMsgDataType.JSON
                    , json.writeValueAsString(entityNode)
                    , null, null, 0L);
            actorService.onMsg(new ServiceToRuleEngineMsg(msg.getTenantId(), tbMsg));
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }
    }

    private void sendRpcRequestToDevice(ToDeviceRpcRequest msg) {
        ToDeviceRpcRequestActorMsg rpcMsg = new ToDeviceRpcRequestActorMsg(routingService.getCurrentServer(), msg);
        log.trace("[{}] Forwarding msg {} to device actor!", msg.getDeviceId(), msg);
        forward(msg.getDeviceId(), rpcMsg);
    }

    private <T extends ToDeviceActorNotificationMsg> void forward(DeviceId deviceId, T msg) {
        actorService.onMsg(new SendToClusterMsg(deviceId, msg));
    }

    private void scheduleTimeout(ToDeviceRpcRequest request, UUID requestId, ConcurrentMap<UUID, Consumer<FromDeviceRpcResponse>> requestsMap) {
        long timeout = Math.max(0, request.getExpirationTime() - System.currentTimeMillis());
        log.trace("[{}] processing the request: [{}]", this.hashCode(), requestId);
        rpcCallBackExecutor.schedule(() -> {
            log.trace("[{}] timeout the request: [{}]", this.hashCode(), requestId);
            Consumer<FromDeviceRpcResponse> consumer = requestsMap.remove(requestId);
            if (consumer != null) {
                consumer.accept(new FromDeviceRpcResponse(requestId, null, null, RpcError.TIMEOUT));
            }
        }, timeout, TimeUnit.MILLISECONDS);
    }


}
