#!/usr/bin/env python3
from cereal import car
from selfdrive.config import Conversions as CV
from selfdrive.car.gm.values import CAR, CruiseButtons, \
                                    AccState
from selfdrive.car import STD_CARGO_KG, scale_rot_inertia, scale_tire_stiffness, gen_empty_fingerprint
from selfdrive.car.interfaces import CarInterfaceBase

ButtonType = car.CarState.ButtonEvent.Type
EventName = car.CarEvent.EventName

class CarInterface(CarInterfaceBase):

  @staticmethod
  def compute_gb(accel, speed):
    return float(accel) / 4.0

  @staticmethod
  def get_params(candidate, fingerprint=gen_empty_fingerprint(), car_fw=None):
    ret = CarInterfaceBase.get_std_params(candidate, fingerprint)
    ret.carName = "gm"
    ret.safetyModel = car.CarParams.SafetyModel.gm
    ret.enableCruise = False  # stock cruise control is kept off

    # GM port is a community feature
    # TODO: make a port that uses a car harness and it only intercepts the camera
    ret.communityFeature = True

    # Presence of a camera on the object bus is ok.
    # Have to go to read_only if ASCM is online (ACC-enabled cars),
    # or camera is on powertrain bus (LKA cars without ACC).
    ret.enableCamera = True
    ret.openpilotLongitudinalControl = ret.enableCamera
    tire_stiffness_factor = 0.444  # not optimized yet

    # Start with a baseline lateral tuning for all GM vehicles. Override tuning as needed in each model section below.
    ret.minSteerSpeed = 7 * CV.MPH_TO_MS
    ret.lateralTuning.pid.kiBP, ret.lateralTuning.pid.kpBP = [[0.], [0.]]
    ret.lateralTuning.pid.kpV, ret.lateralTuning.pid.kiV = [[0.2], [0.00]]
    ret.lateralTuning.pid.kf = 0.00004   # full torque for 20 deg at 80mph means 0.00007818594
    ret.steerRateCost = 1.0
    ret.steerActuatorDelay = 0.1  # Default delay, not measured yet

    if candidate == CAR.VOLT:
      # supports stop and go, but initial engage must be above 18mph (which include conservatism)
      ret.minEnableSpeed = 18 * CV.MPH_TO_MS
      ret.mass = 1607. + STD_CARGO_KG
      ret.wheelbase = 2.69
      ret.steerRatio = 15.7
      ret.steerRatioRear = 0.
      ret.centerToFront = ret.wheelbase * 0.4  # wild guess

    elif candidate == CAR.MALIBU:
      # supports stop and go, but initial engage must be above 18mph (which include conservatism)
      ret.minEnableSpeed = 18 * CV.MPH_TO_MS
      ret.mass = 1496. + STD_CARGO_KG
      ret.wheelbase = 2.83
      ret.steerRatio = 15.8
      ret.steerRatioRear = 0.
      ret.centerToFront = ret.wheelbase * 0.4  # wild guess

    elif candidate == CAR.HOLDEN_ASTRA:
      ret.mass = 1363. + STD_CARGO_KG
      ret.wheelbase = 2.662
      # Remaining parameters copied from Volt for now
      ret.centerToFront = ret.wheelbase * 0.4
      ret.minEnableSpeed = 18 * CV.MPH_TO_MS
      ret.steerRatio = 15.7
      ret.steerRatioRear = 0.

    elif candidate == CAR.ACADIA:
      ret.minEnableSpeed = -1.  # engage speed is decided by pcm
      ret.mass = 4353. * CV.LB_TO_KG + STD_CARGO_KG
      ret.wheelbase = 2.86
      ret.steerRatio = 14.4  # end to end is 13.46
      ret.steerRatioRear = 0.
      ret.centerToFront = ret.wheelbase * 0.4

    elif candidate == CAR.BUICK_REGAL:
      ret.minEnableSpeed = 18 * CV.MPH_TO_MS
      ret.mass = 3779. * CV.LB_TO_KG + STD_CARGO_KG  # (3849+3708)/2
      ret.wheelbase = 2.83  # 111.4 inches in meters
      ret.steerRatio = 14.4  # guess for tourx
      ret.steerRatioRear = 0.
      ret.centerToFront = ret.wheelbase * 0.4  # guess for tourx

    elif candidate == CAR.CADILLAC_ATS:
      ret.minEnableSpeed = 18 * CV.MPH_TO_MS
      ret.mass = 1601. + STD_CARGO_KG
      ret.wheelbase = 2.78
      ret.steerRatio = 15.3
      ret.steerRatioRear = 0.
      ret.centerToFront = ret.wheelbase * 0.49

    # TODO: get actual value, for now starting with reasonable value for
    # civic and scaling by mass and wheelbase
    ret.rotationalInertia = scale_rot_inertia(ret.mass, ret.wheelbase)

    # TODO: start from empirically derived lateral slip stiffness for the civic and scale by
    # mass and CG position, so all cars will have approximately similar dyn behaviors
    ret.tireStiffnessFront, ret.tireStiffnessRear = scale_tire_stiffness(ret.mass, ret.wheelbase, ret.centerToFront,
                                                                         tire_stiffness_factor=tire_stiffness_factor)

    ret.longitudinalTuning.kpBP = [5., 35.]
    ret.longitudinalTuning.kpV = [2.4, 1.5]
    ret.longitudinalTuning.kiBP = [0.]
    ret.longitudinalTuning.kiV = [0.36]

    ret.stoppingControl = True
    ret.startAccel = 0.8

    ret.steerLimitTimer = 0.4
    ret.radarTimeStep = 0.0667  # GM radar runs at 15Hz instead of standard 20Hz

    return ret

  # returns a car.CarState
  def update(self, c, can_strings):
    self.cp.update_strings(can_strings)

    ret = self.CS.update(self.cp)

    ret.canValid = self.cp.can_valid
    ret.steeringRateLimited = self.CC.steer_rate_limited if self.CC is not None else False

    buttonEvents = []

    if self.CS.cruise_buttons != self.CS.prev_cruise_buttons and self.CS.prev_cruise_buttons != CruiseButtons.INIT:
      be = car.CarState.ButtonEvent.new_message()
      be.type = ButtonType.unknown
      if self.CS.cruise_buttons != CruiseButtons.UNPRESS:
        be.pressed = True
        but = self.CS.cruise_buttons
      else:
        be.pressed = False
        but = self.CS.prev_cruise_buttons
      if but == CruiseButtons.RES_ACCEL:
        if not (ret.cruiseState.enabled and ret.standstill):
          be.type = ButtonType.accelCruise  # Suppress resume button if we're resuming from stop so we don't adjust speed.
      elif but == CruiseButtons.DECEL_SET:
        be.type = ButtonType.decelCruise
      elif but == CruiseButtons.CANCEL:
        be.type = ButtonType.cancel
      elif but == CruiseButtons.MAIN:
        be.type = ButtonType.altButton3
      buttonEvents.append(be)

    ret.buttonEvents = buttonEvents

    events = self.create_common_events(ret, pcm_enable=False)

    if ret.vEgo < self.CP.minEnableSpeed:
      events.add(EventName.belowEngageSpeed)
    if self.CS.park_brake:
      events.add(EventName.parkBrake)
    if ret.cruiseState.standstill:
      events.add(EventName.resumeRequired)
    if self.CS.pcm_acc_status == AccState.FAULTED:
      events.add(EventName.controlsFailed)
    if ret.vEgo < self.CP.minSteerSpeed:
      events.add(car.CarEvent.EventName.belowSteerSpeed)

    # handle button presses
    for b in ret.buttonEvents:
      # do enable on both accel and decel buttons
      if b.type in [ButtonType.accelCruise, ButtonType.decelCruise] and not b.pressed:
        events.add(EventName.buttonEnable)
      # do disable on button down
      if b.type == ButtonType.cancel and b.pressed:
        events.add(EventName.buttonCancel)

    ret.events = events.to_msg()

    # copy back carState packet to CS
    self.CS.out = ret.as_reader()

    return self.CS.out

  def apply(self, c):
    hud_v_cruise = c.hudControl.setSpeed
    if hud_v_cruise > 70:
      hud_v_cruise = 0

    # For Openpilot, "enabled" includes pre-enable.
    # In GM, PCM faults out if ACC command overlaps user gas.
    enabled = c.enabled and not self.CS.out.gasPressed

    can_sends = self.CC.update(enabled, self.CS, self.frame,
                               c.actuators,
                               hud_v_cruise, c.hudControl.lanesVisible,
                               c.hudControl.leadVisible, c.hudControl.visualAlert)

    self.frame += 1
    return can_sends
