from cereal import car
from common.realtime import DT_CTRL
from common.numpy_fast import interp
from selfdrive.config import Conversions as CV
from selfdrive.car import apply_std_steer_torque_limits
from selfdrive.car.gm import gmcan
from selfdrive.car.gm.values import DBC, SUPERCRUISE_CARS, CanBus
from opendbc.can.packer import CANPacker

VisualAlert = car.CarControl.HUDControl.VisualAlert


class CarControllerParams():
  def __init__(self, car_fingerprint):
    if car_fingerprint in SUPERCRUISE_CARS:
      self.STEER_MAX = 150
      self.STEER_STEP = 1              # how often we update the steer cmd
      self.STEER_DELTA_UP = 2          # 0.75s time to peak torque
      self.STEER_DELTA_DOWN = 5        # 0.3s from peak torque to zero
      self.MIN_STEER_SPEED = -1.       # can steer down to zero
    else:
      self.STEER_MAX = 300
      self.STEER_STEP = 2              # how often we update the steer cmd
      self.STEER_DELTA_UP = 7          # ~0.75s time to peak torque (255/50hz/0.75s)
      self.STEER_DELTA_DOWN = 17       # ~0.3s from peak torque to zero
      self.MIN_STEER_SPEED = 3.

    self.STEER_DRIVER_ALLOWANCE = 50   # allowed driver torque before start limiting
    self.STEER_DRIVER_MULTIPLIER = 4   # weight driver torque heavily
    self.STEER_DRIVER_FACTOR = 100     # from dbc
    self.NEAR_STOP_BRAKE_PHASE = 0.5 # m/s, more aggressive braking near full stop

    # Takes case of "Service Adaptive Cruise" and "Service Front Camera"
    # dashboard messages.
    self.ADAS_KEEPALIVE_STEP = 100
    self.CAMERA_KEEPALIVE_STEP = 100

    # pedal lookups, only for Volt
    MAX_GAS = 3072              # Only a safety limit
    ZERO_GAS = 2048
    MAX_BRAKE = 350             # Should be around 3.5m/s^2, including regen
    self.MAX_ACC_REGEN = 1404  # ACC Regen braking is slightly less powerful than max regen paddle
    self.GAS_LOOKUP_BP = [-0.25, 0., 0.5]
    self.GAS_LOOKUP_V = [self.MAX_ACC_REGEN, ZERO_GAS, MAX_GAS]
    self.BRAKE_LOOKUP_BP = [-1., -0.25]
    self.BRAKE_LOOKUP_V = [MAX_BRAKE, 0]


def actuator_hystereses(final_pedal, pedal_steady):
  # hyst params... TODO: move these to VehicleParams
  pedal_hyst_gap = 0.01    # don't change pedal command for small oscillations within this value

  # for small pedal oscillations within pedal_hyst_gap, don't change the pedal command
  if final_pedal == 0.:
    pedal_steady = 0.
  elif final_pedal > pedal_steady + pedal_hyst_gap:
    pedal_steady = final_pedal - pedal_hyst_gap
  elif final_pedal < pedal_steady - pedal_hyst_gap:
    pedal_steady = final_pedal + pedal_hyst_gap
  final_pedal = pedal_steady

  return final_pedal, pedal_steady

def process_hud_alert(hud_alert):
  # initialize to no alert
  steer = 0
  if hud_alert == VisualAlert.steerRequired:
    steer = 1
  return steer

class CarController():
  def __init__(self, dbc_name, CP, VM):
    self.pedal_steady = 0.
    self.start_time = 0.
    self.apply_steer_last = 0
    self.car_fingerprint = CP.carFingerprint
    self.lka_icon_status_last = (False, False)
    self.steer_rate_limited = False

    self.params = CarControllerParams(CP.carFingerprint)

    self.packer_pt = CANPacker(DBC[CP.carFingerprint]['pt'])
    self.packer_ch = CANPacker(DBC[CP.carFingerprint]['chassis'])

  def update(self, enabled, CS, frame, actuators, \
             hud_v_cruise, hud_show_lanes, hud_show_car, hud_alert):

    P = self.params

    # Send CAN commands.
    can_sends = []

    alert_out = process_hud_alert(hud_alert)
    steer = alert_out

    ### STEER ###

    if (frame % P.STEER_STEP) == 0:
      lkas_enabled = enabled and not CS.steer_warning and CS.out.vEgo > P.MIN_STEER_SPEED
      if lkas_enabled:
        new_steer = actuators.steer * P.STEER_MAX
        apply_steer = apply_std_steer_torque_limits(new_steer, self.apply_steer_last, CS.out.steeringTorque, P)
        self.steer_rate_limited = new_steer != apply_steer
      else:
        apply_steer = 0

      self.apply_steer_last = apply_steer
      idx = (frame // P.STEER_STEP) % 4

      if self.car_fingerprint in SUPERCRUISE_CARS:
        can_sends += gmcan.create_steering_control_ct6(self.packer_pt,
          CanBus, apply_steer, CS.out.vEgo, idx, lkas_enabled)
      else:
        can_sends.append(gmcan.create_steering_control(self.packer_pt,
          CanBus.POWERTRAIN, apply_steer, idx, lkas_enabled))

    ### GAS/BRAKE ###

    if self.car_fingerprint not in SUPERCRUISE_CARS:
      # no output if not enabled, but keep sending keepalive messages
      # treat pedals as one
      final_pedal = actuators.gas - actuators.brake

      # *** apply pedal hysteresis ***
      final_brake, self.brake_steady = actuator_hystereses(
        final_pedal, self.pedal_steady)

      if not enabled:
        # Stock ECU sends max regen when not enabled.
        apply_gas = P.MAX_ACC_REGEN
        apply_brake = 0
      else:
        apply_gas = int(round(interp(final_pedal, P.GAS_LOOKUP_BP, P.GAS_LOOKUP_V)))
        apply_brake = int(round(interp(final_pedal, P.BRAKE_LOOKUP_BP, P.BRAKE_LOOKUP_V)))

      # Gas/regen and brakes - all at 25Hz
      if (frame % 4) == 0:
        idx = (frame // 4) % 4

        at_full_stop = enabled and CS.out.standstill
        near_stop = enabled and (CS.out.vEgo < P.NEAR_STOP_BRAKE_PHASE)
        can_sends.append(gmcan.create_friction_brake_command(self.packer_ch, CanBus.CHASSIS, apply_brake, idx, near_stop, at_full_stop))

        at_full_stop = enabled and CS.out.standstill
        can_sends.append(gmcan.create_gas_regen_command(self.packer_pt, CanBus.POWERTRAIN, apply_gas, idx, enabled, at_full_stop))

      # Send dashboard UI commands (ACC status), 25hz
      if (frame % 4) == 0:
        can_sends.append(gmcan.create_acc_dashboard_command(self.packer_pt, CanBus.POWERTRAIN, enabled, hud_v_cruise * CV.MS_TO_KPH, hud_show_car))

      # Radar needs to know current speed and yaw rate (50hz),
      # and that ADAS is alive (10hz)
      time_and_headlights_step = 10
      tt = frame * DT_CTRL

      if frame % time_and_headlights_step == 0:
        idx = (frame // time_and_headlights_step) % 4
        can_sends.append(gmcan.create_adas_time_status(CanBus.OBSTACLE, int((tt - self.start_time) * 60), idx))
        can_sends.append(gmcan.create_adas_headlights_status(CanBus.OBSTACLE))

      speed_and_accelerometer_step = 2
      if frame % speed_and_accelerometer_step == 0:
        idx = (frame // speed_and_accelerometer_step) % 4
        can_sends.append(gmcan.create_adas_steering_status(CanBus.OBSTACLE, idx))
        can_sends.append(gmcan.create_adas_accelerometer_speed_status(CanBus.OBSTACLE, CS.out.vEgo, idx))

      if frame % P.ADAS_KEEPALIVE_STEP == 0:
        can_sends += gmcan.create_adas_keepalive(CanBus.POWERTRAIN)

      # Show green icon when LKA torque is applied, and
      # alarming orange icon when approaching torque limit.
      # If not sent again, LKA icon disappears in about 5 seconds.
      # Conveniently, sending camera message periodically also works as a keepalive.
      lka_active = CS.lkas_status == 1
      lka_critical = lka_active and abs(actuators.steer) > 0.9
      lka_icon_status = (lka_active, lka_critical)
      if frame % P.CAMERA_KEEPALIVE_STEP == 0 \
          or lka_icon_status != self.lka_icon_status_last:
        can_sends.append(gmcan.create_lka_icon_command(CanBus.SW_GMLAN, lka_active, lka_critical, steer))
        self.lka_icon_status_last = lka_icon_status

    return can_sends