from cereal import car
from common.numpy_fast import clip, interp
from selfdrive.car import apply_toyota_steer_torque_limits, create_gas_command, make_can_msg
from selfdrive.car.toyota.toyotacan import create_steer_command, create_ui_command, \
                                           create_ipas_steer_command, create_accel_command, \
                                           create_acc_cancel_command, create_fcw_command
from selfdrive.car.toyota.values import Ecu, CAR, STATIC_MSGS, SteerLimitParams
from opendbc.can.packer import CANPacker

VisualAlert = car.CarControl.HUDControl.VisualAlert

# Accel limits
ACCEL_HYST_GAP = 0.02  # don't change accel command for small oscilalitons within this value
ACCEL_MAX = 1.5  # 1.5 m/s2
ACCEL_MIN = -3.0 # 3   m/s2
ACCEL_SCALE = max(ACCEL_MAX, -ACCEL_MIN)


# Steer angle limits (tested at the Crows Landing track and considered ok)
ANGLE_MAX_BP = [0., 5.]
ANGLE_MAX_V = [510., 300.]
ANGLE_DELTA_BP = [0., 5., 15.]
ANGLE_DELTA_V = [5., .8, .15]     # windup limit
ANGLE_DELTA_VU = [5., 3.5, 0.4]   # unwind limit

def accel_hysteresis(accel, accel_steady, enabled):

  # for small accel oscillations within ACCEL_HYST_GAP, don't change the accel command
  if not enabled:
    # send 0 when disabled, otherwise acc faults
    accel_steady = 0.
  elif accel > accel_steady + ACCEL_HYST_GAP:
    accel_steady = accel - ACCEL_HYST_GAP
  elif accel < accel_steady - ACCEL_HYST_GAP:
    accel_steady = accel + ACCEL_HYST_GAP
  accel = accel_steady

  return accel, accel_steady


def process_hud_alert(hud_alert):
  # initialize to no alert
  steer = 0
  fcw = 0

  if hud_alert == VisualAlert.fcw:
    fcw = 1
  elif hud_alert == VisualAlert.steerRequired:
    steer = 1

  return steer, fcw


def ipas_state_transition(steer_angle_enabled, enabled, ipas_active, ipas_reset_counter):

  if enabled and not steer_angle_enabled:
    #ipas_reset_counter = max(0, ipas_reset_counter - 1)
    #if ipas_reset_counter == 0:
    #  steer_angle_enabled = True
    #else:
    #  steer_angle_enabled = False
    #return steer_angle_enabled, ipas_reset_counter
    return True, 0

  elif enabled and steer_angle_enabled:
    if steer_angle_enabled and not ipas_active:
      ipas_reset_counter += 1
    else:
      ipas_reset_counter = 0
    if ipas_reset_counter > 10:  # try every 0.1s
      steer_angle_enabled = False
    return steer_angle_enabled, ipas_reset_counter

  else:
    return False, 0


class CarController():
  def __init__(self, dbc_name, CP, VM):
    self.braking = False
    self.last_steer = 0
    self.last_angle = 0
    self.accel_steady = 0.
    self.car_fingerprint = CP.carFingerprint
    self.alert_active = False
    self.last_standstill = False
    self.standstill_req = False
    self.angle_control = False

    self.steer_angle_enabled = False
    self.ipas_reset_counter = 0
    self.last_fault_frame = -200
    self.steer_rate_limited = False

    self.fake_ecus = set()
    if CP.enableCamera: self.fake_ecus.add(Ecu.fwdCamera)
    if CP.enableDsu: self.fake_ecus.add(Ecu.dsu)
    if CP.enableApgs: self.fake_ecus.add(Ecu.apgs)

    self.packer = CANPacker(dbc_name)

  def update(self, enabled, CS, frame, actuators, pcm_cancel_cmd, hud_alert,
             left_line, right_line, lead, left_lane_depart, right_lane_depart):

    # *** compute control surfaces ***

    # gas and brake

    apply_gas = clip(actuators.gas, 0., 1.)

    if CS.CP.enableGasInterceptor:
      # send only negative accel if interceptor is detected. otherwise, send the regular value
      # +0.06 offset to reduce ABS pump usage when OP is engaged
      apply_accel = 0.06 - actuators.brake
    else:
      apply_accel = actuators.gas - actuators.brake

    apply_accel, self.accel_steady = accel_hysteresis(apply_accel, self.accel_steady, enabled)
    apply_accel = clip(apply_accel * ACCEL_SCALE, ACCEL_MIN, ACCEL_MAX)

    # steer torque
    new_steer = int(round(actuators.steer * SteerLimitParams.STEER_MAX))
    apply_steer = apply_toyota_steer_torque_limits(new_steer, self.last_steer, CS.out.steeringTorqueEps, SteerLimitParams)
    self.steer_rate_limited = new_steer != apply_steer

    # only cut torque when steer state is a known fault
    if CS.steer_state in [9, 25]:
      self.last_fault_frame = frame

    # Cut steering for 2s after fault
    if not enabled or (frame - self.last_fault_frame < 200):
      apply_steer = 0
      apply_steer_req = 0
    else:
      apply_steer_req = 1

    self.steer_angle_enabled, self.ipas_reset_counter = \
      ipas_state_transition(self.steer_angle_enabled, enabled, CS.ipas_active, self.ipas_reset_counter)
    #print("{0} {1} {2}".format(self.steer_angle_enabled, self.ipas_reset_counter, CS.ipas_active))

    # steer angle
    if self.steer_angle_enabled and CS.ipas_active:
      apply_angle = actuators.steerAngle
      angle_lim = interp(CS.out.vEgo, ANGLE_MAX_BP, ANGLE_MAX_V)
      apply_angle = clip(apply_angle, -angle_lim, angle_lim)

      # windup slower
      if self.last_angle * apply_angle > 0. and abs(apply_angle) > abs(self.last_angle):
        angle_rate_lim = interp(CS.out.vEgo, ANGLE_DELTA_BP, ANGLE_DELTA_V)
      else:
        angle_rate_lim = interp(CS.out.vEgo, ANGLE_DELTA_BP, ANGLE_DELTA_VU)

      apply_angle = clip(apply_angle, self.last_angle - angle_rate_lim, self.last_angle + angle_rate_lim)
    else:
      apply_angle = CS.out.steeringAngle

    if not enabled and CS.pcm_acc_status:
      # send pcm acc cancel cmd if drive is disabled but pcm is still on, or if the system can't be activated
      pcm_cancel_cmd = 1

    # on entering standstill, send standstill request
    if CS.out.standstill and not self.last_standstill:
      self.standstill_req = True
    if CS.pcm_acc_status != 8:
      # pcm entered standstill or it's disabled
      self.standstill_req = False

    self.last_steer = apply_steer
    self.last_angle = apply_angle
    self.last_accel = apply_accel
    self.last_standstill = CS.out.standstill

    can_sends = []

    #*** control msgs ***
    #print("steer {0} {1} {2} {3}".format(apply_steer, min_lim, max_lim, CS.steer_torque_motor)

    # toyota can trace shows this message at 42Hz, with counter adding alternatively 1 and 2;
    # sending it at 100Hz seem to allow a higher rate limit, as the rate limit seems imposed
    # on consecutive messages
    if Ecu.fwdCamera in self.fake_ecus:
      if self.angle_control:
        can_sends.append(create_steer_command(self.packer, 0., 0, frame))
      else:
        can_sends.append(create_steer_command(self.packer, apply_steer, apply_steer_req, frame))

    if self.angle_control:
      can_sends.append(create_ipas_steer_command(self.packer, apply_angle, self.steer_angle_enabled,
                                                 Ecu.apgs in self.fake_ecus))
    elif Ecu.apgs in self.fake_ecus:
      can_sends.append(create_ipas_steer_command(self.packer, 0, 0, True))

    # we can spam can to cancel the system even if we are using lat only control
    if (frame % 3 == 0 and CS.CP.openpilotLongitudinalControl) or (pcm_cancel_cmd and Ecu.fwdCamera in self.fake_ecus):
      lead = lead or CS.out.vEgo < 12.    # at low speed we always assume the lead is present do ACC can be engaged

      # Lexus IS uses a different cancellation message
      if pcm_cancel_cmd and CS.CP.carFingerprint == CAR.LEXUS_IS:
        can_sends.append(create_acc_cancel_command(self.packer))
      elif CS.CP.openpilotLongitudinalControl:
        can_sends.append(create_accel_command(self.packer, apply_accel, pcm_cancel_cmd, self.standstill_req, lead))
      else:
        can_sends.append(create_accel_command(self.packer, 0, pcm_cancel_cmd, False, lead))

    if (frame % 2 == 0) and (CS.CP.enableGasInterceptor):
        # send exactly zero if apply_gas is zero. Interceptor will send the max between read value and apply_gas.
        # This prevents unexpected pedal range rescaling
        can_sends.append(create_gas_command(self.packer, apply_gas, frame//2))

    # ui mesg is at 100Hz but we send asap if:
    # - there is something to display
    # - there is something to stop displaying
    alert_out = process_hud_alert(hud_alert)
    steer, fcw = alert_out

    if (any(alert_out) and not self.alert_active) or \
       (not any(alert_out) and self.alert_active):
      send_ui = True
      self.alert_active = not self.alert_active
    else:
      send_ui = False

    # disengage msg causes a bad fault sound so play a good sound instead
    if pcm_cancel_cmd:
      send_ui = True

    if (frame % 100 == 0 or send_ui) and Ecu.fwdCamera in self.fake_ecus:
      can_sends.append(create_ui_command(self.packer, steer, pcm_cancel_cmd, left_line, right_line, left_lane_depart, right_lane_depart))

    if frame % 100 == 0 and Ecu.dsu in self.fake_ecus:
      can_sends.append(create_fcw_command(self.packer, fcw))

    #*** static msgs ***

    for (addr, ecu, cars, bus, fr_step, vl) in STATIC_MSGS:
      if frame % fr_step == 0 and ecu in self.fake_ecus and self.car_fingerprint in cars:
        can_sends.append(make_can_msg(addr, vl, bus))

    return can_sends
