#include "GCodeTimeEstimator.hpp"
#include <boost/bind.hpp>
#include <cmath>

static const std::string AXIS_STR = "XYZE";
static const float MMMIN_TO_MMSEC = 1.0f / 60.0f;
static const float MILLISEC_TO_SEC = 0.001f;
static const float INCHES_TO_MM = 25.4f;
static const float DEFAULT_FEEDRATE = 1500.0f; // from Prusa Firmware (Marlin_main.cpp)
static const float DEFAULT_ACCELERATION = 1500.0f; // Prusa Firmware 1_75mm_MK2
static const float DEFAULT_RETRACT_ACCELERATION = 1500.0f; // Prusa Firmware 1_75mm_MK2
static const float DEFAULT_AXIS_MAX_FEEDRATE[] = { 500.0f, 500.0f, 12.0f, 120.0f }; // Prusa Firmware 1_75mm_MK2
static const float DEFAULT_AXIS_MAX_ACCELERATION[] = { 9000.0f, 9000.0f, 500.0f, 10000.0f }; // Prusa Firmware 1_75mm_MK2
static const float DEFAULT_AXIS_MAX_JERK[] = { 10.0f, 10.0f, 0.2f, 2.5f }; // from Prusa Firmware (Configuration.h)
static const float DEFAULT_MINIMUM_FEEDRATE = 0.0f; // from Prusa Firmware (Configuration_adv.h)
static const float DEFAULT_MINIMUM_TRAVEL_FEEDRATE = 0.0f; // from Prusa Firmware (Configuration_adv.h)

#if USE_CURA_JUNCTION_VMAX
static const float MINIMUM_PLANNER_SPEED = 0.05f; // from Cura <<<<<<<< WHAT IS THIS ???
#endif // USE_CURA_JUNCTION_VMAX

static const float PREVIOUS_FEEDRATE_THRESHOLD = 0.0001f;

namespace Slic3r {

  void GCodeTimeEstimator::Feedrates::reset()
  {
    feedrate = 0.0f;
    safe_feedrate = 0.0f;
    ::memset(axis_feedrate, 0, Num_Axis * sizeof(float));
    ::memset(abs_axis_feedrate, 0, Num_Axis * sizeof(float));
  }

  float GCodeTimeEstimator::Block::Trapezoid::acceleration_time(float acceleration) const
  {
    return acceleration_time_from_distance(feedrate.entry, accelerate_until, acceleration);
  }

  float GCodeTimeEstimator::Block::Trapezoid::cruise_time() const
  {
    return (feedrate.cruise != 0.0f) ? cruise_distance() / feedrate.cruise : 0.0f;
  }

  float GCodeTimeEstimator::Block::Trapezoid::deceleration_time(float acceleration) const
  {
    return acceleration_time_from_distance(feedrate.cruise, (distance - decelerate_after), -acceleration);
  }

  float GCodeTimeEstimator::Block::Trapezoid::cruise_distance() const
  {
    return decelerate_after - accelerate_until;
  }

  float GCodeTimeEstimator::Block::Trapezoid::acceleration_time_from_distance(float initial_feedrate, float distance, float acceleration)
  {
    return (acceleration != 0.0f) ? (speed_from_distance(initial_feedrate, distance, acceleration) - initial_feedrate) / acceleration : 0.0f;
  }

  float GCodeTimeEstimator::Block::Trapezoid::speed_from_distance(float initial_feedrate, float distance, float acceleration)
  {
    return ::sqrt(sqr(initial_feedrate) + 2.0f * acceleration * distance);
  }

  float GCodeTimeEstimator::Block::move_length() const
  {
    float length = ::sqrt(sqr(delta_pos[X]) + sqr(delta_pos[Y]) + sqr(delta_pos[Z]));
    return (length > 0.0f) ? length : ::abs(delta_pos[E]);
  }

  float GCodeTimeEstimator::Block::is_extruder_only_move() const
  {
    return (delta_pos[X] == 0.0f) && (delta_pos[Y] == 0.0f) && (delta_pos[Z] == 0.0f) && (delta_pos[E] != 0.0f);
  }

  float GCodeTimeEstimator::Block::is_travel_move() const
  {
    return delta_pos[E] == 0.0f;
  }

  float GCodeTimeEstimator::Block::acceleration_time() const
  {
    return trapezoid.acceleration_time(acceleration);
  }

  float GCodeTimeEstimator::Block::cruise_time() const
  {
    return trapezoid.cruise_time();
  }

  float GCodeTimeEstimator::Block::deceleration_time() const
  {
    return trapezoid.deceleration_time(acceleration);
  }

  float GCodeTimeEstimator::Block::cruise_distance() const
  {
    return trapezoid.cruise_distance();
  }

  void GCodeTimeEstimator::Block::calculate_trapezoid()
  {
    float distance = move_length();

    trapezoid.distance = distance;
    trapezoid.feedrate = feedrate;

    float accelerate_distance = estimate_acceleration_distance(feedrate.entry, feedrate.cruise, acceleration);
    float decelerate_distance = estimate_acceleration_distance(feedrate.cruise, feedrate.exit, -acceleration);
    float cruise_distance = distance - accelerate_distance - decelerate_distance;

    // Not enough space to reach the nominal feedrate.
    // This means no cruising, and we'll have to use intersection_distance() to calculate when to abort acceleration 
    // and start braking in order to reach the exit_feedrate exactly at the end of this block.
    if (cruise_distance < 0.0f)
    {
      accelerate_distance = clamp(0.0f, distance, intersection_distance(feedrate.entry, feedrate.exit, acceleration, distance));
      cruise_distance = 0.0f;
      trapezoid.feedrate.cruise = Trapezoid::speed_from_distance(feedrate.entry, accelerate_distance, acceleration);
    }

    trapezoid.accelerate_until = accelerate_distance;
    trapezoid.decelerate_after = accelerate_distance + cruise_distance;
  }

  float GCodeTimeEstimator::Block::max_allowable_speed(float acceleration, float target_velocity, float distance)
  {
    return ::sqrt(sqr(target_velocity) - 2.0f * acceleration * distance);
  }

  float GCodeTimeEstimator::Block::estimate_acceleration_distance(float initial_rate, float target_rate, float acceleration)
  {
    return (acceleration == 0.0f) ? 0.0f : (sqr(target_rate) - sqr(initial_rate)) / (2.0f * acceleration);
  }

  float GCodeTimeEstimator::Block::intersection_distance(float initial_rate, float final_rate, float acceleration, float distance)
  {
    return (acceleration == 0.0f) ? 0.0f : (2.0f * acceleration * distance - sqr(initial_rate) + sqr(final_rate)) / (4.0f * acceleration);
  }

  GCodeTimeEstimator::GCodeTimeEstimator()
  {
    reset();
    set_default();
  }

  void GCodeTimeEstimator::calculate_time_from_text(const std::string& gcode)
  {
    _parser.parse(gcode, boost::bind(&GCodeTimeEstimator::_process_gcode_line, this, _1, _2));
    _calculate_time();
    reset();
  }

  void GCodeTimeEstimator::calculate_time_from_file(const std::string& file)
  {
    _parser.parse_file(file, boost::bind(&GCodeTimeEstimator::_process_gcode_line, this, _1, _2));
    _calculate_time();
    reset();
  }

  void GCodeTimeEstimator::add_gcode_line(const std::string& gcode_line)
  {
    _parser.parse_line(gcode_line, boost::bind(&GCodeTimeEstimator::_process_gcode_line, this, _1, _2));
  }

  void GCodeTimeEstimator::calculate_time()
  {
    _calculate_time();
    _reset();
  }

  void GCodeTimeEstimator::set_axis_position(EAxis axis, float position)
  {
    _state.axis[axis].position = position;
  }

  void GCodeTimeEstimator::set_axis_max_feedrate(EAxis axis, float feedrate_mm_sec)
  {
    _state.axis[axis].max_feedrate = feedrate_mm_sec;
  }

  void GCodeTimeEstimator::set_axis_max_acceleration(EAxis axis, float acceleration)
  {
    _state.axis[axis].max_acceleration = acceleration;
  }

  void GCodeTimeEstimator::set_axis_max_jerk(EAxis axis, float jerk)
  {
    _state.axis[axis].max_jerk = jerk;
  }

  float GCodeTimeEstimator::get_axis_position(EAxis axis) const
  {
    return _state.axis[axis].position;
  }

  float GCodeTimeEstimator::get_axis_max_feedrate(EAxis axis) const
  {
    return _state.axis[axis].max_feedrate;
  }

  float GCodeTimeEstimator::get_axis_max_acceleration(EAxis axis) const
  {
    return _state.axis[axis].max_acceleration;
  }

  float GCodeTimeEstimator::get_axis_max_jerk(EAxis axis) const
  {
    return _state.axis[axis].max_jerk;
  }

  void GCodeTimeEstimator::set_feedrate(float feedrate_mm_sec)
  {
    _state.feedrate = feedrate_mm_sec;
  }

  float GCodeTimeEstimator::get_feedrate() const
  {
    return _state.feedrate;
  }

  void GCodeTimeEstimator::set_acceleration(float acceleration_mm_sec2)
  {
    _state.acceleration = acceleration_mm_sec2;
  }

  float GCodeTimeEstimator::get_acceleration() const
  {
    return _state.acceleration;
  }

  void GCodeTimeEstimator::set_retract_acceleration(float acceleration_mm_sec2)
  {
    _state.retract_acceleration = acceleration_mm_sec2;
  }

  float GCodeTimeEstimator::get_retract_acceleration() const
  {
    return _state.retract_acceleration;
  }

  void GCodeTimeEstimator::set_minimum_feedrate(float feedrate_mm_sec)
  {
    _state.minimum_feedrate = feedrate_mm_sec;
  }

  float GCodeTimeEstimator::get_minimum_feedrate() const
  {
    return _state.minimum_feedrate;
  }

  void GCodeTimeEstimator::set_minimum_travel_feedrate(float feedrate_mm_sec)
  {
    _state.minimum_travel_feedrate = feedrate_mm_sec;
  }

  float GCodeTimeEstimator::get_minimum_travel_feedrate() const
  {
    return _state.minimum_travel_feedrate;
  }

  void GCodeTimeEstimator::set_dialect(GCodeTimeEstimator::EDialect dialect)
  {
    _state.dialect = dialect;
  }

  GCodeTimeEstimator::EDialect GCodeTimeEstimator::get_dialect() const
  {
    return _state.dialect;
  }

  void GCodeTimeEstimator::set_units(GCodeTimeEstimator::EUnits units)
  {
    _state.units = units;
  }

  GCodeTimeEstimator::EUnits GCodeTimeEstimator::get_units() const
  {
    return _state.units;
  }

  void GCodeTimeEstimator::set_positioning_xyz_type(GCodeTimeEstimator::EPositioningType type)
  {
    _state.positioning_xyz_type = type;
  }

  GCodeTimeEstimator::EPositioningType GCodeTimeEstimator::get_positioning_xyz_type() const
  {
    return _state.positioning_xyz_type;
  }

  void GCodeTimeEstimator::set_positioning_e_type(GCodeTimeEstimator::EPositioningType type)
  {
    _state.positioning_e_type = type;
  }

  GCodeTimeEstimator::EPositioningType GCodeTimeEstimator::get_positioning_e_type() const
  {
    return _state.positioning_e_type;
  }

  void GCodeTimeEstimator::add_additional_time(float timeSec)
  {
    _state.additional_time += timeSec;
  }

  void GCodeTimeEstimator::set_additional_time(float timeSec)
  {
    _state.additional_time = timeSec;
  }

  float GCodeTimeEstimator::get_additional_time() const
  {
    return _state.additional_time;
  }

  void GCodeTimeEstimator::set_default()
  {
    set_units(Millimeters);
    set_dialect(Unknown);
    set_positioning_xyz_type(Absolute);
    set_positioning_e_type(Relative);

    set_feedrate(DEFAULT_FEEDRATE);
    set_acceleration(DEFAULT_ACCELERATION);
    set_retract_acceleration(DEFAULT_RETRACT_ACCELERATION);
    set_minimum_feedrate(DEFAULT_MINIMUM_FEEDRATE);
    set_minimum_travel_feedrate(DEFAULT_MINIMUM_TRAVEL_FEEDRATE);

    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      EAxis axis = (EAxis)a;
      set_axis_max_feedrate(axis, DEFAULT_AXIS_MAX_FEEDRATE[a]);
      set_axis_max_acceleration(axis, DEFAULT_AXIS_MAX_ACCELERATION[a]);
      set_axis_max_jerk(axis, DEFAULT_AXIS_MAX_JERK[a]);
    }
  }

  void GCodeTimeEstimator::reset()
  {
    _blocks.clear();
    _reset();
  }

  float GCodeTimeEstimator::get_time() const
  {
    return _time;
  }

  std::string GCodeTimeEstimator::get_time_hms() const
  {
    float timeinsecs = get_time();
    int hours = (int)(timeinsecs / 3600.0f);
    timeinsecs -= (float)hours * 3600.0f;
    int minutes = (int)(timeinsecs / 60.0f);
    timeinsecs -= (float)minutes * 60.0f;

    char buffer[16];
    ::sprintf(buffer, "%02d:%02d:%02d", hours, minutes, (int)timeinsecs);
    return buffer;
  }

  void GCodeTimeEstimator::_reset()
  {
    _curr.reset();
    _prev.reset();

    set_axis_position(X, 0.0f);
    set_axis_position(Y, 0.0f);
    set_axis_position(Z, 0.0f);

    set_additional_time(0.0f);
  }

  void GCodeTimeEstimator::_calculate_time()
  {
#if ENABLE_BLOCKS_PRE_PROCESSING
    forward_pass();
    reverse_pass();
    recalculate_trapezoids();
#endif // ENABLE_BLOCKS_PRE_PROCESSING

    _time = get_additional_time();

    for (const Block& block : _blocks)
    {
      _time += block.acceleration_time();
      _time += block.cruise_time();
      _time += block.deceleration_time();
    }
  }

  void GCodeTimeEstimator::_process_gcode_line(GCodeReader&, const GCodeReader::GCodeLine& line)
  {
    if (line.cmd.length() > 1)
    {
      switch (line.cmd[0])
      {
      case 'G':
        {
          switch (::atoi(&line.cmd[1]))
          {
          case 1: // Move
            {
              _processG1(line);
              break;
            }
          case 4: // Dwell
            {
              _processG4(line);
              break;
            }
          case 20: // Set Units to Inches
            {
              _processG20(line);
              break;
            }
          case 21: // Set Units to Millimeters
            {
              _processG21(line);
              break;
            }
          case 28: // Move to Origin (Home)
            {
              _processG28(line);
              break;
            }
          case 90: // Set to Absolute Positioning
            {
              _processG90(line);
              break;
            }
          case 91: // Set to Relative Positioning
            {
              _processG91(line);
              break;
            }
          case 92: // Set Position
            {
              _processG92(line);
              break;
            }
          }

          break;
        }
      case 'M':
        {
          switch (::atoi(&line.cmd[1]))
          {
          case 82: // Set extruder to absolute mode
            {
              _processM82(line);
              break;
            }
          case 83: // Set extruder to relative mode
            {
              _processM83(line);
              break;
            }
          case 109: // Set Extruder Temperature and Wait
            {
              _processM109(line);
              break;
            }
          case 201: // Set max printing acceleration
            {
              _processM201(line);
              break;
            }
          case 203: // Set maximum feedrate
            {
              _processM203(line);
              break;
            }
          case 204: // Set default acceleration
            {
              _processM204(line);
              break;
            }
          case 205: // Advanced settings
            {
              _processM205(line);
              break;
            }
          case 566: // Set allowable instantaneous speed change
            {
              _processM566(line);
              break;
            }
          }

          break;
        }
      }
    }
  }

  // Returns the new absolute position on the given axis in dependence of the given parameters
  float axis_absolute_position_from_G1_line(GCodeTimeEstimator::EAxis axis, const GCodeReader::GCodeLine& lineG1, GCodeTimeEstimator::EUnits units, GCodeTimeEstimator::EPositioningType type, float current_absolute_position)
  {
    float lengthsScaleFactor = (units == GCodeTimeEstimator::Inches) ? INCHES_TO_MM : 1.0f;
    if (lineG1.has(AXIS_STR[axis]))
    {
      float ret = lineG1.get_float(AXIS_STR[axis]) * lengthsScaleFactor;
      return (type == GCodeTimeEstimator::Absolute) ? ret : current_absolute_position + ret;
    }
    else
      return current_absolute_position;
  }

  void GCodeTimeEstimator::_processG1(const GCodeReader::GCodeLine& line)
  {
    // updates axes positions from line
    EUnits units = get_units();
    float new_pos[Num_Axis];
    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      new_pos[a] = axis_absolute_position_from_G1_line((EAxis)a, line, units, (a == E) ? get_positioning_e_type() : get_positioning_xyz_type(), get_axis_position((EAxis)a));
    }

    // updates feedrate from line, if present
    if (line.has('F'))
      set_feedrate(std::max(line.get_float('F') * MMMIN_TO_MMSEC, get_minimum_feedrate()));

    // fills block data
    Block block;

    // calculates block movement deltas
    float max_abs_delta = 0.0f;
    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      block.delta_pos[a] = new_pos[a] - get_axis_position((EAxis)a);
      max_abs_delta = std::max(max_abs_delta, ::abs(block.delta_pos[a]));
    }

    // is it a move ?
    if (max_abs_delta == 0.0f)
      return;

    // calculates block feedrate
    _curr.feedrate = std::max(get_feedrate(), block.is_travel_move() ? get_minimum_travel_feedrate() : get_minimum_feedrate());

    float distance = block.move_length();
    float invDistance = 1.0f / distance;

    float min_feedrate_factor = 1.0f;
    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      _curr.axis_feedrate[a] = _curr.feedrate * block.delta_pos[a] * invDistance;
      _curr.abs_axis_feedrate[a] = ::abs(_curr.axis_feedrate[a]);
      if (_curr.abs_axis_feedrate[a] > 0.0f)
        min_feedrate_factor = std::min(min_feedrate_factor, get_axis_max_feedrate((EAxis)a) / _curr.abs_axis_feedrate[a]);
    }
    
    block.feedrate.cruise = min_feedrate_factor * _curr.feedrate;

    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      _curr.axis_feedrate[a] *= min_feedrate_factor;
      _curr.abs_axis_feedrate[a] *= min_feedrate_factor;
    }

    // calculates block acceleration
    float acceleration = block.is_extruder_only_move() ? get_retract_acceleration() : get_acceleration();

    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      float axis_max_acceleration = get_axis_max_acceleration((EAxis)a);
      if (acceleration * ::abs(block.delta_pos[a]) * invDistance > axis_max_acceleration)
        acceleration = axis_max_acceleration;
    }

    block.acceleration = acceleration;

    // calculates block exit feedrate
    _curr.safe_feedrate = block.feedrate.cruise;

    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      float axis_max_jerk = get_axis_max_jerk((EAxis)a);
      if (_curr.abs_axis_feedrate[a] > axis_max_jerk)
        _curr.safe_feedrate = std::min(_curr.safe_feedrate, axis_max_jerk);
    }

    block.feedrate.exit = _curr.safe_feedrate;

    // calculates block entry feedrate
#if USE_CURA_JUNCTION_VMAX
    float vmax_junction = _curr.safe_feedrate;
    if (!_blocks.empty() && (_prev.feedrate > PREVIOUS_FEEDRATE_THRESHOLD))
    {
      vmax_junction = block.feedrate.cruise;
      float vmax_junction_factor = 1.0f;

      for (unsigned char a = X; a < Num_Axis; ++a)
      {
        float abs_delta_axis_feedrate = ::abs(_curr.axis_feedrate[a] - _prev.axis_feedrate[a]);
        float axis_max_jerk = get_axis_max_jerk((EAxis)a);
        if (abs_delta_axis_feedrate > axis_max_jerk)
          vmax_junction_factor = std::min(vmax_junction_factor, axis_max_jerk / abs_delta_axis_feedrate);
      }

      // limit vmax to not exceed previous feedrate
      vmax_junction = std::min(_prev.feedrate, vmax_junction * vmax_junction_factor);
    }

#if ENABLE_BLOCKS_PRE_PROCESSING
    float v_allowable = Block::max_allowable_speed(-acceleration, MINIMUM_PLANNER_SPEED, distance);
    block.feedrate.entry = std::min(vmax_junction, v_allowable);
#else
    block.feedrate.entry = std::min(vmax_junction, Block::max_allowable_speed(-acceleration, MINIMUM_PLANNER_SPEED, distance));
#endif // ENABLE_BLOCKS_PRE_PROCESSING
#else
    float vmax_junction = _curr.safe_feedrate;
    if (!_blocks.empty() && (_prev.feedrate > PREVIOUS_FEEDRATE_THRESHOLD))
    {
      bool prev_speed_larger = _prev.feedrate > block.feedrate.cruise;
      float smaller_speed_factor = prev_speed_larger ? (block.feedrate.cruise / _prev.feedrate) : (_prev.feedrate / block.feedrate.cruise);
      // Pick the smaller of the nominal speeds. Higher speed shall not be achieved at the junction during coasting.
      vmax_junction = prev_speed_larger ? block.feedrate.cruise : _prev.feedrate;

      float v_factor = 1.0f;
      bool limited = false;

      for (unsigned char a = X; a < Num_Axis; ++a)
      {
        // Limit an axis. We have to differentiate coasting from the reversal of an axis movement, or a full stop.
        float v_exit = _prev.axis_feedrate[a];
        float v_entry = _curr.axis_feedrate[a];

        if (prev_speed_larger)
          v_exit *= smaller_speed_factor;

        if (limited)
        {
          v_exit *= v_factor;
          v_entry *= v_factor;
        }

        // Calculate the jerk depending on whether the axis is coasting in the same direction or reversing a direction.
        float jerk =
          (v_exit > v_entry) ?
          (((v_entry > 0.0f) || (v_exit < 0.0f)) ?
          // coasting
          (v_exit - v_entry) :
          // axis reversal
          std::max(v_exit, -v_entry)) :
          // v_exit <= v_entry
          (((v_entry < 0.0f) || (v_exit > 0.0f)) ?
          // coasting
          (v_entry - v_exit) :
          // axis reversal
          std::max(-v_exit, v_entry));

        float axis_max_jerk = get_axis_max_jerk((EAxis)a);
        if (jerk > axis_max_jerk)
        {
          v_factor *= axis_max_jerk / jerk;
          limited = true;
        }
      }

      if (limited)
        vmax_junction *= v_factor;

      // Now the transition velocity is known, which maximizes the shared exit / entry velocity while
      // respecting the jerk factors, it may be possible, that applying separate safe exit / entry velocities will achieve faster prints.
      float vmax_junction_threshold = vmax_junction * 0.99f;

      // Not coasting. The machine will stop and start the movements anyway, better to start the segment from start.
      if ((_prev.safe_feedrate > vmax_junction_threshold) && (_curr.safe_feedrate > vmax_junction_threshold))
        vmax_junction = _curr.safe_feedrate;
    }

#if ENABLE_BLOCKS_PRE_PROCESSING
    float v_allowable = Block::max_allowable_speed(-acceleration, _curr.safe_feedrate, distance);
    block.feedrate.entry = std::min(vmax_junction, v_allowable);
#else
    block.feedrate.entry = std::min(vmax_junction, Block::max_allowable_speed(-acceleration, _curr.safe_feedrate, distance));
#endif // ENABLE_BLOCKS_PRE_PROCESSING
#endif // USE_CURA_JUNCTION_VMAX

#if ENABLE_BLOCKS_PRE_PROCESSING
    block.max_entry_speed = vmax_junction;
    block.flags.nominal_length = (block.feedrate.cruise <= v_allowable);
    block.flags.recalculate = true;
    block.safe_feedrate = _curr.safe_feedrate;
#endif // ENABLE_BLOCKS_PRE_PROCESSING

    // calculates block trapezoid
    block.calculate_trapezoid();

    // updates previous
    _prev = _curr;

    // updates axis positions
    for (unsigned char a = X; a < Num_Axis; ++a)
    {
      set_axis_position((EAxis)a, new_pos[a]);
    }

    // adds block to blocks list
    _blocks.push_back(block);
  }

  void GCodeTimeEstimator::_processG4(const GCodeReader::GCodeLine& line)
  {
    EDialect dialect = get_dialect();

    if (line.has('P'))
      add_additional_time(line.get_float('P') * MILLISEC_TO_SEC);

    // see: http://reprap.org/wiki/G-code#G4:_Dwell
    if ((dialect == Repetier) ||
        (dialect == Marlin) ||
        (dialect == Smoothieware) ||
        (dialect == RepRapFirmware))
    {
      if (line.has('S'))
        add_additional_time(line.get_float('S'));
    }
  }

  void GCodeTimeEstimator::_processG20(const GCodeReader::GCodeLine& line)
  {
    set_units(Inches);
  }

  void GCodeTimeEstimator::_processG21(const GCodeReader::GCodeLine& line)
  {
    set_units(Millimeters);
  }

  void GCodeTimeEstimator::_processG28(const GCodeReader::GCodeLine& line)
  {
    // todo
  }

  void GCodeTimeEstimator::_processG90(const GCodeReader::GCodeLine& line)
  {
    set_positioning_xyz_type(Absolute);
  }

  void GCodeTimeEstimator::_processG91(const GCodeReader::GCodeLine& line)
  {
    // >>>>>>>> THERE ARE DIALECT VARIANTS

    set_positioning_xyz_type(Relative);
  }

  void GCodeTimeEstimator::_processM82(const GCodeReader::GCodeLine& line)
  {
    set_positioning_e_type(Absolute);
  }

  void GCodeTimeEstimator::_processM83(const GCodeReader::GCodeLine& line)
  {
    set_positioning_e_type(Relative);
  }

  void GCodeTimeEstimator::_processG92(const GCodeReader::GCodeLine& line)
  {
    float lengthsScaleFactor = (get_units() == Inches) ? INCHES_TO_MM : 1.0f;
    bool anyFound = false;

    if (line.has('X'))
    {
      set_axis_position(X, line.get_float('X') * lengthsScaleFactor);
      anyFound = true;
    }

    if (line.has('Y'))
    {
      set_axis_position(Y, line.get_float('Y') * lengthsScaleFactor);
      anyFound = true;
    }

    if (line.has('Z'))
    {
      set_axis_position(Z, line.get_float('Z') * lengthsScaleFactor);
      anyFound = true;
    }

    if (line.has('E'))
    {
      set_axis_position(E, line.get_float('E') * lengthsScaleFactor);
      anyFound = true;
    }

    if (!anyFound)
    {
      for (unsigned char a = X; a < Num_Axis; ++a)
      {
        set_axis_position((EAxis)a, 0.0f);
      }
    }
  }

  void GCodeTimeEstimator::_processM109(const GCodeReader::GCodeLine& line)
  {
    // todo
  }

  void GCodeTimeEstimator::_processM201(const GCodeReader::GCodeLine& line)
  {
    EDialect dialect = get_dialect();

    // see http://reprap.org/wiki/G-code#M201:_Set_max_printing_acceleration
    float factor = ((dialect != RepRapFirmware) && (get_units() == GCodeTimeEstimator::Inches)) ? INCHES_TO_MM : 1.0f;

    if (line.has('X'))
      set_axis_max_acceleration(X, line.get_float('X') * factor);

    if (line.has('Y'))
      set_axis_max_acceleration(Y, line.get_float('Y') * factor);

    if (line.has('Z'))
      set_axis_max_acceleration(Z, line.get_float('Z') * factor);

    if (line.has('E'))
      set_axis_max_acceleration(E, line.get_float('E') * factor);
  }

  void GCodeTimeEstimator::_processM203(const GCodeReader::GCodeLine& line)
  {
    EDialect dialect = get_dialect();

    // see http://reprap.org/wiki/G-code#M203:_Set_maximum_feedrate
    if (dialect == Repetier)
      return;

    // see http://reprap.org/wiki/G-code#M203:_Set_maximum_feedrate
    float factor = (dialect == Marlin) ? 1.0f : MMMIN_TO_MMSEC;

    if (line.has('X'))
      set_axis_max_feedrate(X, line.get_float('X') * factor);

    if (line.has('Y'))
      set_axis_max_feedrate(Y, line.get_float('Y') * factor);

    if (line.has('Z'))
      set_axis_max_feedrate(Z, line.get_float('Z') * factor);

    if (line.has('E'))
      set_axis_max_feedrate(E, line.get_float('E') * factor);
  }

  void GCodeTimeEstimator::_processM204(const GCodeReader::GCodeLine& line)
  {
    if (line.has('S'))
      set_acceleration(line.get_float('S'));

    if (line.has('T'))
      set_retract_acceleration(line.get_float('T'));
  }

  void GCodeTimeEstimator::_processM205(const GCodeReader::GCodeLine& line)
  {
    if (line.has('X'))
    {
      float max_jerk = line.get_float('X');
      set_axis_max_jerk(X, max_jerk);
      set_axis_max_jerk(Y, max_jerk);
    }

    if (line.has('Y'))
      set_axis_max_jerk(Y, line.get_float('Y'));

    if (line.has('Z'))
      set_axis_max_jerk(Z, line.get_float('Z'));

    if (line.has('E'))
      set_axis_max_jerk(E, line.get_float('E'));

    if (line.has('S'))
      set_minimum_feedrate(line.get_float('S'));

    if (line.has('T'))
      set_minimum_travel_feedrate(line.get_float('T'));
  }

  void GCodeTimeEstimator::_processM566(const GCodeReader::GCodeLine& line)
  {
    if (line.has('X'))
      set_axis_max_jerk(X, line.get_float('X') * MMMIN_TO_MMSEC);

    if (line.has('Y'))
      set_axis_max_jerk(Y, line.get_float('Y') * MMMIN_TO_MMSEC);

    if (line.has('Z'))
      set_axis_max_jerk(Z, line.get_float('Z') * MMMIN_TO_MMSEC);

    if (line.has('E'))
      set_axis_max_jerk(E, line.get_float('E') * MMMIN_TO_MMSEC);
  }

#if ENABLE_BLOCKS_PRE_PROCESSING
  void GCodeTimeEstimator::forward_pass()
  {
    Block* block[2] = { nullptr, nullptr };

    for (Block& b : _blocks)
    {
      block[0] = block[1];
      block[1] = &b;
      planner_forward_pass_kernel(block[0], block[1]);
    }

    planner_forward_pass_kernel(block[1], nullptr);
  }

  void GCodeTimeEstimator::reverse_pass()
  {
    Block* block[2] = { nullptr, nullptr };

    for (int i = (int)_blocks.size() - 1; i >= 0; --i)
    {
      block[1] = block[0];
      block[0] = &_blocks[i];
      planner_reverse_pass_kernel(block[0], block[1]);
    }
  }

  void GCodeTimeEstimator::planner_forward_pass_kernel(Block* prev, Block* curr)
  {
    if (prev == nullptr)
      return;

    // If the previous block is an acceleration block, but it is not long enough to complete the
    // full speed change within the block, we need to adjust the entry speed accordingly. Entry
    // speeds have already been reset, maximized, and reverse planned by reverse planner.
    // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
    if (!prev->flags.nominal_length)
    {
      if (prev->feedrate.entry < curr->feedrate.entry)
      {
        float entry_speed = std::min(curr->feedrate.entry, Block::max_allowable_speed(-prev->acceleration, prev->feedrate.entry, prev->move_length()));

        // Check for junction speed change
        if (curr->feedrate.entry != entry_speed)
        {
          curr->feedrate.entry = entry_speed;
          curr->flags.recalculate = true;
        }
      }
    }
  }

  void GCodeTimeEstimator::planner_reverse_pass_kernel(Block* curr, Block* next)
  {
    if ((curr == nullptr) || (next == nullptr))
      return;

    // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
    // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
    // check for maximum allowable speed reductions to ensure maximum possible planned speed.
    if (curr->feedrate.entry != curr->max_entry_speed)
    {
      // If nominal length true, max junction speed is guaranteed to be reached. Only compute
      // for max allowable speed if block is decelerating and nominal length is false.
      if (!curr->flags.nominal_length && (curr->max_entry_speed > next->feedrate.entry))
        curr->feedrate.entry = std::min(curr->max_entry_speed, Block::max_allowable_speed(-curr->acceleration, next->feedrate.entry, curr->move_length()));
      else
        curr->feedrate.entry = curr->max_entry_speed;

      curr->flags.recalculate = true;
    }
  }

  void GCodeTimeEstimator::recalculate_trapezoids()
  {
    Block* curr = nullptr;
    Block* next = nullptr;

    for (Block& b : _blocks)
    {
      curr = next;
      next = &b;

      if (curr != nullptr)
      {
        // Recalculate if current block entry or exit junction speed has changed.
        if (curr->flags.recalculate || next->flags.recalculate)
        {
          // NOTE: Entry and exit factors always > 0 by all previous logic operations.
          Block block = *curr;
          block.feedrate.exit = next->feedrate.entry;
          block.calculate_trapezoid();
          curr->trapezoid = block.trapezoid;
          curr->flags.recalculate = false; // Reset current only to ensure next trapezoid is computed
        }
      }
    }

    // Last/newest block in buffer. Exit speed is set with MINIMUM_PLANNER_SPEED. Always recalculated.
    if (next != nullptr)
    {
      Block block = *next;
#if USE_CURA_JUNCTION_VMAX
      block.feedrate.exit = MINIMUM_PLANNER_SPEED;
#else
      block.feedrate.exit = next->safe_feedrate;
#endif // USE_CURA_JUNCTION_VMAX
      block.calculate_trapezoid();
      next->trapezoid = block.trapezoid;
      next->flags.recalculate = false;
    }
  }
#endif // ENABLE_BLOCKS_PRE_PROCESSING

}