/*
 * Copyright 2017 The Cartographer 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.
 */

#include "cartographer_grpc/map_builder_server.h"

#include "cartographer_grpc/handlers/add_fixed_frame_pose_data_handler.h"
#include "cartographer_grpc/handlers/add_imu_data_handler.h"
#include "cartographer_grpc/handlers/add_odometry_data_handler.h"
#include "cartographer_grpc/handlers/add_rangefinder_data_handler.h"
#include "cartographer_grpc/handlers/add_trajectory_handler.h"
#include "cartographer_grpc/handlers/finish_trajectory_handler.h"
#include "cartographer_grpc/handlers/receive_local_slam_results_handler.h"
#include "cartographer_grpc/proto/map_builder_service.grpc.pb.h"
#include "glog/logging.h"

namespace cartographer_grpc {
namespace {

const cartographer::common::Duration kPopTimeout =
    cartographer::common::FromMilliseconds(100);

}  // namespace

MapBuilderServer::MapBuilderContext::MapBuilderContext(
    MapBuilderServer* map_builder_server)
    : map_builder_server_(map_builder_server) {}

cartographer::mapping::MapBuilderInterface&
MapBuilderServer::MapBuilderContext::map_builder() {
  return *map_builder_server_->map_builder_;
}

cartographer::common::BlockingQueue<
    std::unique_ptr<MapBuilderServer::SensorData>>&
MapBuilderServer::MapBuilderContext::sensor_data_queue() {
  return map_builder_server_->sensor_data_queue_;
}

cartographer::mapping::TrajectoryBuilderInterface::LocalSlamResultCallback
MapBuilderServer::MapBuilderContext::
    GetLocalSlamResultCallbackForSubscriptions() {
  MapBuilderServer* map_builder_server = map_builder_server_;
  return [map_builder_server](
             int trajectory_id, cartographer::common::Time time,
             cartographer::transform::Rigid3d local_pose,
             cartographer::sensor::RangeData range_data,
             std::unique_ptr<const cartographer::mapping::NodeId> node_id) {
    map_builder_server->OnLocalSlamResult(trajectory_id, time, local_pose,
                                          std::move(range_data),
                                          std::move(node_id));
  };
}

void MapBuilderServer::MapBuilderContext::AddSensorDataToTrajectory(
    const SensorData& sensor_data) {
  sensor_data.sensor_data->AddToTrajectoryBuilder(
      map_builder_server_->map_builder_->GetTrajectoryBuilder(
          sensor_data.trajectory_id));
}

MapBuilderServer::SubscriptionId
MapBuilderServer::MapBuilderContext::SubscribeLocalSlamResults(
    int trajectory_id, LocalSlamSubscriptionCallback callback) {
  return map_builder_server_->SubscribeLocalSlamResults(trajectory_id,
                                                        callback);
}

void MapBuilderServer::MapBuilderContext::UnsubscribeLocalSlamResults(
    const SubscriptionId& subscription_id) {
  map_builder_server_->UnsubscribeLocalSlamResults(subscription_id);
}

MapBuilderServer::MapBuilderServer(
    const proto::MapBuilderServerOptions& map_builder_server_options,
    std::unique_ptr<cartographer::mapping::MapBuilderInterface> map_builder)
    : map_builder_(std::move(map_builder)) {
  framework::Server::Builder server_builder;
  server_builder.SetServerAddress(map_builder_server_options.server_address());
  server_builder.SetNumGrpcThreads(
      map_builder_server_options.num_grpc_threads());
  server_builder.SetNumEventThreads(
      map_builder_server_options.num_event_threads());
  server_builder.RegisterHandler<handlers::AddTrajectoryHandler,
                                 proto::MapBuilderService>("AddTrajectory");
  server_builder.RegisterHandler<handlers::AddOdometryDataHandler,
                                 proto::MapBuilderService>("AddOdometryData");
  server_builder
      .RegisterHandler<handlers::AddImuDataHandler, proto::MapBuilderService>(
          "AddImuData");
  server_builder.RegisterHandler<handlers::AddRangefinderDataHandler,
                                 proto::MapBuilderService>(
      "AddRangefinderData");
  server_builder.RegisterHandler<handlers::AddFixedFramePoseDataHandler,
                                 proto::MapBuilderService>(
      "AddFixedFramePoseData");
  server_builder.RegisterHandler<handlers::FinishTrajectoryHandler,
                                 proto::MapBuilderService>("FinishTrajectory");
  server_builder.RegisterHandler<handlers::ReceiveLocalSlamResultsHandler,
                                 proto::MapBuilderService>(
      "ReceiveLocalSlamResults");
  grpc_server_ = server_builder.Build();
  grpc_server_->SetExecutionContext(
      cartographer::common::make_unique<MapBuilderContext>(this));
}

void MapBuilderServer::Start() {
  shutting_down_ = false;
  StartSlamThread();
  grpc_server_->Start();
}

void MapBuilderServer::WaitForShutdown() {
  grpc_server_->WaitForShutdown();
  if (slam_thread_) {
    slam_thread_->join();
  }
}

void MapBuilderServer::Shutdown() {
  shutting_down_ = true;
  grpc_server_->Shutdown();
  if (slam_thread_) {
    slam_thread_->join();
  }
}

void MapBuilderServer::ProcessSensorDataQueue() {
  LOG(INFO) << "Starting SLAM thread.";
  while (!shutting_down_) {
    std::unique_ptr<SensorData> sensor_data =
        sensor_data_queue_.PopWithTimeout(kPopTimeout);
    if (sensor_data) {
      grpc_server_->GetContext<MapBuilderContext>()->AddSensorDataToTrajectory(
          *sensor_data);
    }
  }
}

void MapBuilderServer::StartSlamThread() {
  CHECK(!slam_thread_);

  // Start the SLAM processing thread.
  slam_thread_ = cartographer::common::make_unique<std::thread>(
      [this]() { this->ProcessSensorDataQueue(); });
}

void MapBuilderServer::OnLocalSlamResult(
    int trajectory_id, cartographer::common::Time time,
    cartographer::transform::Rigid3d local_pose,
    cartographer::sensor::RangeData range_data,
    std::unique_ptr<const cartographer::mapping::NodeId> node_id) {
  auto shared_range_data =
      std::make_shared<cartographer::sensor::RangeData>(std::move(range_data));
  cartographer::common::MutexLocker locker(&local_slam_subscriptions_lock_);
  for (auto& entry : local_slam_subscriptions_[trajectory_id]) {
    auto copy_of_node_id =
        node_id ? cartographer::common::make_unique<
                      const cartographer::mapping::NodeId>(*node_id)
                : nullptr;
    LocalSlamSubscriptionCallback callback = entry.second;
    callback(trajectory_id, time, local_pose, shared_range_data,
             std::move(copy_of_node_id));
  }
}

MapBuilderServer::SubscriptionId MapBuilderServer::SubscribeLocalSlamResults(
    int trajectory_id, LocalSlamSubscriptionCallback callback) {
  cartographer::common::MutexLocker locker(&local_slam_subscriptions_lock_);
  local_slam_subscriptions_[trajectory_id].emplace(current_subscription_index_,
                                                   callback);
  return SubscriptionId{trajectory_id, current_subscription_index_++};
}

void MapBuilderServer::UnsubscribeLocalSlamResults(
    const SubscriptionId& subscription_id) {
  cartographer::common::MutexLocker locker(&local_slam_subscriptions_lock_);
  CHECK_EQ(local_slam_subscriptions_[subscription_id.trajectory_id].erase(
               subscription_id.subscription_index),
           1u);
}

}  // namespace cartographer_grpc