text: #!/usr/bin/env python3
  import math
  import numpy as np
  from common.params import Params
  from common.numpy_fast import interp
  
  import cereal.messaging as messaging
  from cereal import car
  from common.realtime import sec_since_boot
  from selfdrive.swaglog import cloudlog
  from selfdrive.config import Conversions as CV
  from selfdrive.controls.lib.speed_smoother import speed_smoother
  from selfdrive.controls.lib.longcontrol import LongCtrlState, MIN_CAN_SPEED
  from selfdrive.controls.lib.fcw import FCWChecker
  from selfdrive.controls.lib.long_mpc import LongitudinalMpc
  
  MAX_SPEED = 255.0
  
  LON_MPC_STEP = 0.2  # first step is 0.2s
  MAX_SPEED_ERROR = 2.0
  AWARENESS_DECEL = -0.2     # car smoothly decel at .2m/s^2 when user is distracted
  
  # lookup tables VS speed to determine min and max accels in cruise
  # make sure these accelerations are smaller than mpc limits
  _A_CRUISE_MIN_V  = [-1.0, -.8, -.67, -.5, -.30]
  _A_CRUISE_MIN_BP = [   0., 5.,  10., 20.,  40.]
  
  # need fast accel at very low speed for stop and go
  # make sure these accelerations are smaller than mpc limits
  _A_CRUISE_MAX_V = [1.2, 1.2, 0.65, .4]
  _A_CRUISE_MAX_V_FOLLOWING = [1.6, 1.6, 0.65, .4]
  _A_CRUISE_MAX_BP = [0.,  6.4, 22.5, 40.]
  
  # Lookup table for turns
  _A_TOTAL_MAX_V = [1.7, 3.2]
  _A_TOTAL_MAX_BP = [20., 40.]
  
  # 75th percentile
  SPEED_PERCENTILE_IDX = 7
  
  
  def calc_cruise_accel_limits(v_ego, following):
    a_cruise_min = interp(v_ego, _A_CRUISE_MIN_BP, _A_CRUISE_MIN_V)
  
    if following:
      a_cruise_max = interp(v_ego, _A_CRUISE_MAX_BP, _A_CRUISE_MAX_V_FOLLOWING)
    else:
      a_cruise_max = interp(v_ego, _A_CRUISE_MAX_BP, _A_CRUISE_MAX_V)
    return np.vstack([a_cruise_min, a_cruise_max])
  
  
  def limit_accel_in_turns(v_ego, angle_steers, a_target, CP):
    """
    This function returns a limited long acceleration allowed, depending on the existing lateral acceleration
    this should avoid accelerating when losing the target in turns
    """
  
    a_total_max = interp(v_ego, _A_TOTAL_MAX_BP, _A_TOTAL_MAX_V)
    a_y = v_ego**2 * angle_steers * CV.DEG_TO_RAD / (CP.steerRatio * CP.wheelbase)
    a_x_allowed = math.sqrt(max(a_total_max**2 - a_y**2, 0.))
  
    return [a_target[0], min(a_target[1], a_x_allowed)]
  
  
  class Planner():
    def __init__(self, CP):
      self.CP = CP
  
      self.mpc1 = LongitudinalMpc(1)
      self.mpc2 = LongitudinalMpc(2)
  
      self.v_acc_start = 0.0
      self.a_acc_start = 0.0
  
      self.v_acc = 0.0
      self.v_acc_future = 0.0
      self.a_acc = 0.0
      self.v_cruise = 0.0
      self.a_cruise = 0.0
      self.v_model = 0.0
      self.a_model = 0.0
  
      self.longitudinalPlanSource = 'cruise'
      self.fcw_checker = FCWChecker()
      self.path_x = np.arange(192)
  
      self.params = Params()
      self.first_loop = True
  
    def choose_solution(self, v_cruise_setpoint, enabled):
      if enabled:
        solutions = {'model': self.v_model, 'cruise': self.v_cruise}
        if self.mpc1.prev_lead_status:
          solutions['mpc1'] = self.mpc1.v_mpc
        if self.mpc2.prev_lead_status:
          solutions['mpc2'] = self.mpc2.v_mpc
  
        slowest = min(solutions, key=solutions.get)
  
        self.longitudinalPlanSource = slowest
        # Choose lowest of MPC and cruise
        if slowest == 'mpc1':
          self.v_acc = self.mpc1.v_mpc
          self.a_acc = self.mpc1.a_mpc
        elif slowest == 'mpc2':
          self.v_acc = self.mpc2.v_mpc
          self.a_acc = self.mpc2.a_mpc
        elif slowest == 'cruise':
          self.v_acc = self.v_cruise
          self.a_acc = self.a_cruise
        elif slowest == 'model':
          self.v_acc = self.v_model
          self.a_acc = self.a_model
  
      self.v_acc_future = min([self.mpc1.v_mpc_future, self.mpc2.v_mpc_future, v_cruise_setpoint])
  
    def update(self, sm, pm, CP, VM, PP):
      """Gets called when new radarState is available"""
      cur_time = sec_since_boot()
      v_ego = sm['carState'].vEgo
  
      long_control_state = sm['controlsState'].longControlState
      v_cruise_kph = sm['controlsState'].vCruise
      force_slow_decel = sm['controlsState'].forceDecel
      v_cruise_setpoint = v_cruise_kph * CV.KPH_TO_MS
  
      lead_1 = sm['radarState'].leadOne
      lead_2 = sm['radarState'].leadTwo
  
      enabled = (long_control_state == LongCtrlState.pid) or (long_control_state == LongCtrlState.stopping)
      following = lead_1.status and lead_1.dRel < 45.0 and lead_1.vLeadK > v_ego and lead_1.aLeadK > 0.0
  
      if len(sm['model'].path.poly):
        path = list(sm['model'].path.poly)
  
        # Curvature of polynomial https://en.wikipedia.org/wiki/Curvature#Curvature_of_the_graph_of_a_function
        # y = a x^3 + b x^2 + c x + d, y' = 3 a x^2 + 2 b x + c, y'' = 6 a x + 2 b
        # k = y'' / (1 + y'^2)^1.5
        # TODO: compute max speed without using a list of points and without numpy
        y_p = 3 * path[0] * self.path_x**2 + 2 * path[1] * self.path_x + path[2]
        y_pp = 6 * path[0] * self.path_x + 2 * path[1]
        curv = y_pp / (1. + y_p**2)**1.5
  
        a_y_max = 2.975 - v_ego * 0.0375  # ~1.85 @ 75mph, ~2.6 @ 25mph
        v_curvature = np.sqrt(a_y_max / np.clip(np.abs(curv), 1e-4, None))
        model_speed = np.min(v_curvature)
        model_speed = max(20.0 * CV.MPH_TO_MS, model_speed) # Don't slow down below 20mph
  
        curvature = np.mean(curv[1:4])
      else:
        model_speed = MAX_SPEED
        curvature = 0.
  
      # Calculate speed for normal cruise control
      if enabled and not self.first_loop:
        accel_limits = [float(x) for x in calc_cruise_accel_limits(v_ego, following)]
        jerk_limits = [min(-0.1, accel_limits[0]), max(0.1, accel_limits[1])]  # TODO: make a separate lookup for jerk tuning
        accel_limits_turns = limit_accel_in_turns(v_ego, sm['carState'].steeringAngle, accel_limits, self.CP)
  
        if force_slow_decel:
          # if required so, force a smooth deceleration
          accel_limits_turns[1] = min(accel_limits_turns[1], AWARENESS_DECEL)
          accel_limits_turns[0] = min(accel_limits_turns[0], accel_limits_turns[1])
  
        self.v_cruise, self.a_cruise = speed_smoother(self.v_acc_start, self.a_acc_start,
                                                      v_cruise_setpoint,
                                                      accel_limits_turns[1], accel_limits_turns[0],
                                                      jerk_limits[1], jerk_limits[0],
                                                      LON_MPC_STEP)
  
        self.v_model, self.a_model = speed_smoother(self.v_acc_start, self.a_acc_start,
                                                      model_speed,
                                                      2*accel_limits[1], accel_limits[0],
                                                      2*jerk_limits[1], jerk_limits[0],
                                                      LON_MPC_STEP)
  
        # cruise speed can't be negative even is user is distracted
        self.v_cruise = max(self.v_cruise, 0.)
      else:
        starting = long_control_state == LongCtrlState.starting
        a_ego = min(sm['carState'].aEgo, 0.0)
        reset_speed = MIN_CAN_SPEED if starting else v_ego
        reset_accel = self.CP.startAccel if starting else a_ego
        self.v_acc = reset_speed
        self.a_acc = reset_accel
        self.v_acc_start = reset_speed
        self.a_acc_start = reset_accel
        self.v_cruise = reset_speed
        self.a_cruise = reset_accel
  
      self.mpc1.set_cur_state(self.v_acc_start, self.a_acc_start)
      self.mpc2.set_cur_state(self.v_acc_start, self.a_acc_start)
  
      self.mpc1.update(pm, sm['carState'], lead_1, v_cruise_setpoint)
      self.mpc2.update(pm, sm['carState'], lead_2, v_cruise_setpoint)
  
      self.choose_solution(v_cruise_setpoint, enabled)
  
      # determine fcw
      if self.mpc1.new_lead:
        self.fcw_checker.reset_lead(cur_time)
  
      blinkers = sm['carState'].leftBlinker or sm['carState'].rightBlinker
      fcw = self.fcw_checker.update(self.mpc1.mpc_solution, cur_time,
                                    sm['controlsState'].active,
                                    v_ego, sm['carState'].aEgo,
                                    lead_1.dRel, lead_1.vLead, lead_1.aLeadK,
                                    lead_1.yRel, lead_1.vLat,
                                    lead_1.fcw, blinkers) and not sm['carState'].brakePressed
      if fcw:
        cloudlog.info("FCW triggered %s", self.fcw_checker.counters)
  
      radar_dead = not sm.alive['radarState']
  
      radar_errors = list(sm['radarState'].radarErrors)
      radar_fault = car.RadarData.Error.fault in radar_errors
      radar_can_error = car.RadarData.Error.canError in radar_errors
  
      # **** send the plan ****
      plan_send = messaging.new_message('plan')
  
      plan_send.valid = sm.all_alive_and_valid(service_list=['carState', 'controlsState', 'radarState'])
  
      plan_send.plan.mdMonoTime = sm.logMonoTime['model']
      plan_send.plan.radarStateMonoTime = sm.logMonoTime['radarState']
  
      # longitudal plan
      plan_send.plan.vCruise = float(self.v_cruise)
      plan_send.plan.aCruise = float(self.a_cruise)
      plan_send.plan.vStart = float(self.v_acc_start)
      plan_send.plan.aStart = float(self.a_acc_start)
      plan_send.plan.vTarget = float(self.v_acc)
      plan_send.plan.aTarget = float(self.a_acc)
      plan_send.plan.vTargetFuture = float(self.v_acc_future)
      plan_send.plan.hasLead = self.mpc1.prev_lead_status
      plan_send.plan.longitudinalPlanSource = self.longitudinalPlanSource
  
      radar_valid = not (radar_dead or radar_fault)
      plan_send.plan.radarValid = bool(radar_valid)
      plan_send.plan.radarCanError = bool(radar_can_error)
  
      plan_send.plan.processingDelay = (plan_send.logMonoTime / 1e9) - sm.rcv_time['radarState']
  
      # Send out fcw
      plan_send.plan.fcw = fcw
  
      plan_send.plan.pCurvature = float(curvature)
      plan_send.plan.curvMaxSpeed = float(model_speed)
  
      pm.send('plan', plan_send)
  
      # Interpolate 0.05 seconds and save as starting point for next iteration
      a_acc_sol = self.a_acc_start + (CP.radarTimeStep / LON_MPC_STEP) * (self.a_acc - self.a_acc_start)
      v_acc_sol = self.v_acc_start + CP.radarTimeStep * (a_acc_sol + self.a_acc_start) / 2.0
      self.v_acc_start = v_acc_sol
      self.a_acc_start = a_acc_sol
  
      self.first_loop = False
  