/******************************************************************************
 * Copyright 2017 The Apollo Authors. All Rights Reserved.
 *
 * 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 "modules/dreamview/backend/simulation_world/simulation_world_updater.h"

#include "google/protobuf/util/json_util.h"
#include "modules/dreamview/backend/common/dreamview_gflags.h"
#include "modules/map/hdmap/hdmap_util.h"

namespace apollo {
namespace dreamview {

using apollo::common::adapter::AdapterManager;
using apollo::common::monitor::MonitorMessageItem;
using apollo::common::util::GetProtoFromASCIIFile;
using apollo::hdmap::EndWayPointFile;
using apollo::routing::RoutingRequest;
using google::protobuf::util::MessageToJsonString;
using Json = nlohmann::json;

SimulationWorldUpdater::SimulationWorldUpdater(WebSocketHandler *websocket,
                                               const MapService *map_service,
                                               bool routing_from_file)
    : sim_world_service_(map_service, routing_from_file),
      map_service_(map_service),
      websocket_(websocket) {
  // Initialize default end point
  if (!GetProtoFromASCIIFile(EndWayPointFile(), &default_end_point_)) {
    AWARN << "Failed to load default end point from " << EndWayPointFile();
  }

  websocket_->RegisterMessageHandler(
      "RetrieveMapData",
      [this](const Json &json, WebSocketHandler::Connection *conn) {
        auto iter = json.find("elements");
        if (iter != json.end()) {
          MapElementIds map_element_ids(*iter);
          auto retrieved = map_service_->RetrieveMapElements(map_element_ids);

          std::string retrieved_json_string;
          MessageToJsonString(retrieved, &retrieved_json_string);

          Json response;
          response["type"] = "MapData";
          response["data"] = Json::parse(retrieved_json_string);

          websocket_->SendData(conn, response.dump());
        }
      });

  websocket_->RegisterMessageHandler(
      "RetrieveMapElementsByRadius",
      [this](const Json &json, WebSocketHandler::Connection *conn) {
        auto radius = json.find("radius");
        if (radius == json.end()) {
          AERROR << "Cannot retrieve map elements with unknown radius.";
          return;
        }

        Json response = sim_world_service_.GetMapElements(*radius);
        response["type"] = "MapElements";
        websocket_->SendData(conn, response.dump());
      });

  websocket_->RegisterMessageHandler(
      "SendRoutingRequest",
      [this](const Json &json, WebSocketHandler::Connection *conn) {
        RoutingRequest routing_request;

        bool succeed = ConstructRoutingRequest(json, &routing_request);
        if (succeed) {
          AdapterManager::FillRoutingRequestHeader(FLAGS_dreamview_module_name,
                                                   &routing_request);
          AdapterManager::PublishRoutingRequest(routing_request);
        }

        // Publish monitor message.
        if (succeed) {
          sim_world_service_.PublishMonitorMessage(MonitorMessageItem::INFO,
                                                   "Routing Request Sent");
        } else {
          sim_world_service_.PublishMonitorMessage(
              MonitorMessageItem::ERROR, "Failed to send routing request");
        }
      });

  websocket_->RegisterMessageHandler(
      "RequestSimulationWorld",
      [this](const Json &json, WebSocketHandler::Connection *conn) {
        if (!sim_world_service_.ReadyToPush()) {
          AWARN_EVERY(100)
              << "Not sending simulation world as the data is not ready!";
          return;
        }

        std::string to_send;
        {
          // Pay the price to copy the data instead of sending data over the
          // wire while holding the lock.
          boost::shared_lock<boost::shared_mutex> reader_lock(mutex_);
          to_send = simulation_world_json_;
        }
        websocket_->SendData(conn, to_send, true);
      });
}

bool SimulationWorldUpdater::ConstructRoutingRequest(
    const Json &json, RoutingRequest *routing_request) {
  // Input validations
  if (json.find("start") == json.end() ||
      json.find("sendDefaultRoute") == json.end()) {
    AERROR << "Cannot prepare a routing request: input validation failed.";
    return false;
  }

  // set start point
  auto start = json["start"];
  if (start.find("x") == start.end() || start.find("y") == start.end()) {
    AERROR << "Failed to prepare a routing request: start point not found";
    return false;
  }
  map_service_->ConstructLaneWayPoint(start["x"], start["y"],
                                      routing_request->mutable_start());

  // set way point(s) if any
  auto iter = json.find("waypoint");
  if (iter != json.end()) {
    auto *waypoint = routing_request->mutable_waypoint();
    for (size_t i = 0; i < iter->size(); ++i) {
      auto &point = (*iter)[i];
      if (!map_service_->ConstructLaneWayPoint(point["x"], point["y"],
                                               waypoint->Add())) {
        waypoint->RemoveLast();
      }
    }
  }

  // set end point
  RoutingRequest::LaneWaypoint *endLane = routing_request->mutable_end();
  if (json["sendDefaultRoute"]) {
    // Try to reload end point if it hasn't been loaded yet.
    if (!default_end_point_.has_id() &&
        !GetProtoFromASCIIFile(EndWayPointFile(), &default_end_point_)) {
      AERROR << "Failed to load default end point from " << EndWayPointFile();
      return false;
    }

    endLane->set_id(default_end_point_.id());
    endLane->set_s(default_end_point_.s());
    auto *pose = endLane->mutable_pose();
    pose->set_x(default_end_point_.pose().x());
    pose->set_y(default_end_point_.pose().y());
  } else {
    if (json.find("end") == json.end()) {
      AERROR << "Failed to prepare a routing request: end point not found";
      return false;
    }

    auto end = json["end"];
    if (end.find("x") == end.end() || end.find("y") == end.end()) {
      AERROR << "Failed to prepare a routing request: end point not found";
      return false;
    }
    map_service_->ConstructLaneWayPoint(end["x"], end["y"], endLane);
  }

  return true;
}

void SimulationWorldUpdater::Start() {
  // start ROS timer, one-shot = false, auto-start = true
  timer_ = AdapterManager::CreateTimer(ros::Duration(kSimWorldTimeInterval),
                                       &SimulationWorldUpdater::OnTimer, this);
}

void SimulationWorldUpdater::OnTimer(const ros::TimerEvent &event) {
  sim_world_service_.Update();

  {
    boost::unique_lock<boost::shared_mutex> writer_lock(mutex_);

    simulation_world_json_ =
        sim_world_service_.GetUpdateAsJson(FLAGS_map_radius).dump();
  }
}

}  // namespace dreamview
}  // namespace apollo