// this is for emacs file handling -*- mode: c++; indent-tabs-mode: nil -*-

// -- BEGIN LICENSE BLOCK ----------------------------------------------
// Copyright 2019 FZI Forschungszentrum Informatik
//
// 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.
// -- END LICENSE BLOCK ------------------------------------------------

//----------------------------------------------------------------------
/*!\file
 *
 * \author  Felix Mauch mauch@fzi.de
 * \date    2019-04-11
 *
 */
//----------------------------------------------------------------------
#include <ros/ros.h>
#include <controller_manager/controller_manager.h>

#include <csignal>
#include <ur_rtde_driver/ros/hardware_interface.h>

std::unique_ptr<ur_driver::HardwareInterface> g_hw_interface;

void signalHandler(int signum)
{
  std::cout << "Interrupt signal (" << signum << ") received.\n";

  g_hw_interface.reset();
  // cleanup and close up stuff here
  // terminate program

  exit(signum);
}

int main(int argc, char** argv)
{
  // Set up ROS.
  ros::init(argc, argv, "ur_hardware_interface");
  ros::AsyncSpinner spinner(2);
  spinner.start();

  ros::NodeHandle nh;
  ros::NodeHandle nh_priv("~");

  // register signal SIGINT and signal handler
  signal(SIGINT, signalHandler);

  // Set up timers
  ros::Time timestamp;
  ros::Duration period;
  auto stopwatch_last = std::chrono::steady_clock::now();
  auto stopwatch_now = stopwatch_last;

  g_hw_interface.reset(new ur_driver::HardwareInterface);

  if (!g_hw_interface->init(nh, nh_priv))
  {
    ROS_ERROR_STREAM("Could not correctly initialize robot. Exiting");
    exit(1);
  }
  ROS_DEBUG_STREAM("initialized hw interface");
  controller_manager::ControllerManager cm(g_hw_interface.get(), nh);

  // Get current time and elapsed time since last read
  timestamp = ros::Time::now();
  stopwatch_now = std::chrono::steady_clock::now();
  period.fromSec(std::chrono::duration_cast<std::chrono::duration<double>>(stopwatch_now - stopwatch_last).count());
  stopwatch_last = stopwatch_now;

  std::ifstream realtime_file("/sys/kernel/realtime", std::ios::in);
  bool has_realtime;
  realtime_file >> has_realtime;
  if (has_realtime)
  {
    const int max_thread_priority = sched_get_priority_max(SCHED_FIFO);
    if (max_thread_priority != -1)
    {
      // We'll operate on the currently running thread.
      pthread_t this_thread = pthread_self();

      // struct sched_param is used to store the scheduling priority
      struct sched_param params;

      // We'll set the priority to the maximum.
      params.sched_priority = max_thread_priority;

      int ret = pthread_setschedparam(this_thread, SCHED_FIFO, &params);
      if (ret != 0)
      {
        ROS_ERROR_STREAM("Unsuccessful in setting main thread realtime priority. Error code: " << ret);
      }
      // Now verify the change in thread priority
      int policy = 0;
      ret = pthread_getschedparam(this_thread, &policy, &params);
      if (ret != 0)
      {
        std::cout << "Couldn't retrieve real-time scheduling paramers" << std::endl;
      }

      // Check the correct policy was applied
      if (policy != SCHED_FIFO)
      {
        ROS_ERROR("Main thread: Scheduling is NOT SCHED_FIFO!");
      }
      else
      {
        ROS_INFO("Main thread: SCHED_FIFO OK");
      }

      // Print thread scheduling priority
      ROS_INFO_STREAM("Main thread priority is " << params.sched_priority);
    }
    else
    {
      ROS_ERROR("Could not get maximum thread priority for main thread");
    }
  }

  double expected_cycle_time = 1.0 / (static_cast<double>(g_hw_interface->getControlFrequency()));

  // Run as fast as possible
  while (ros::ok())
  {
    // Receive current state from robot
    g_hw_interface->read(timestamp, period);

    // Get current time and elapsed time since last read
    timestamp = ros::Time::now();
    stopwatch_now = std::chrono::steady_clock::now();
    period.fromSec(std::chrono::duration_cast<std::chrono::duration<double>>(stopwatch_now - stopwatch_last).count());
    stopwatch_last = stopwatch_now;

    cm.update(timestamp, period, g_hw_interface->shouldResetControllers());

    g_hw_interface->write(timestamp, period);
    // if (!control_rate.sleep())
    if (period.toSec() > expected_cycle_time)
    {
      // ROS_WARN_STREAM("Could not keep cycle rate of " << expected_cycle_time * 1000 << "ms");
      // ROS_WARN_STREAM("Actual cycle time:" << period.toNSec() / 1000000.0 << "ms");
    }
  }

  spinner.stop();
  ROS_INFO_STREAM_NAMED("hardware_interface", "Shutting down.");
  return 0;
}
