import numpy as np
from common.realtime import DT_CTRL, DT_DMON
from selfdrive.controls.lib.drive_helpers import create_event, EventTypes as ET
from common.filter_simple import FirstOrderFilter
from common.stat_live import RunningStatFilter

_AWARENESS_TIME = 100.  # 1.6 minutes limit without user touching steering wheels make the car enter a terminal status
_AWARENESS_PRE_TIME_TILL_TERMINAL = 25.  # a first alert is issued 25s before expiration
_AWARENESS_PROMPT_TIME_TILL_TERMINAL = 15.  # a second alert is issued 15s before start decelerating the car
_DISTRACTED_TIME = 11.
_DISTRACTED_PRE_TIME_TILL_TERMINAL = 8.
_DISTRACTED_PROMPT_TIME_TILL_TERMINAL = 6.

_FACE_THRESHOLD = 0.4
_EYE_THRESHOLD = 0.4
_BLINK_THRESHOLD = 0.2 # 0.225
_PITCH_WEIGHT = 1.35 # 1.5  # pitch matters a lot more
_METRIC_THRESHOLD = 0.4
_PITCH_POS_ALLOWANCE = 0.04 # 0.08  # rad, to not be too sensitive on positive pitch
_PITCH_NATURAL_OFFSET = 0.12  # 0.1   # people don't seem to look straight when they drive relaxed, rather a bit up
_YAW_NATURAL_OFFSET = 0.08  # people don't seem to look straight when they drive relaxed, rather a bit to the right (center of car)

_DISTRACTED_FILTER_TS = 0.25  # 0.6Hz

_POSE_CALIB_MIN_SPEED = 13 # 30 mph
_POSE_OFFSET_MIN_COUNT = 600 # valid data counts before calibration completes, 1 seg is 600 counts
_POSE_OFFSET_MAX_COUNT = 3600 # stop deweighting new data after 6 min, aka "short term memory"

_RECOVERY_FACTOR_MAX = 5. # relative to minus step change
_RECOVERY_FACTOR_MIN = 1.25 # relative to minus step change

MAX_TERMINAL_ALERTS = 3      # not allowed to engage after 3 terminal alerts

# model output refers to center of cropped image, so need to apply the x displacement offset
RESIZED_FOCAL = 320.0
H, W, FULL_W = 320, 160, 426

class DistractedType(object):
  NOT_DISTRACTED = 0
  BAD_POSE = 1
  BAD_BLINK = 2

def head_orientation_from_descriptor(angles_desc, pos_desc, rpy_calib):
  # the output of these angles are in device frame
  # so from driver's perspective, pitch is up and yaw is right

  pitch_prnet = angles_desc[0]
  yaw_prnet = angles_desc[1]
  roll_prnet = angles_desc[2]

  face_pixel_position = ((pos_desc[0] + .5)*W - W + FULL_W, (pos_desc[1]+.5)*H)
  yaw_focal_angle = np.arctan2(face_pixel_position[0] - FULL_W/2, RESIZED_FOCAL)
  pitch_focal_angle = np.arctan2(face_pixel_position[1] - H/2, RESIZED_FOCAL)

  roll = roll_prnet
  pitch = pitch_prnet + pitch_focal_angle
  yaw = -yaw_prnet + yaw_focal_angle

  # no calib for roll
  pitch -= rpy_calib[1]
  yaw -= rpy_calib[2]
  return np.array([roll, pitch, yaw])

class DriverPose():
  def __init__(self):
    self.yaw = 0.
    self.pitch = 0.
    self.roll = 0.
    self.pitch_offseter = RunningStatFilter(max_trackable=_POSE_OFFSET_MAX_COUNT)
    self.yaw_offseter = RunningStatFilter(max_trackable=_POSE_OFFSET_MAX_COUNT)

class DriverBlink():
  def __init__(self):
    self.left_blink = 0.
    self.right_blink = 0.

class DriverStatus():
  def __init__(self):
    self.pose = DriverPose()
    self.pose_calibrated = self.pose.pitch_offseter.filtered_stat.n > _POSE_OFFSET_MIN_COUNT and \
                            self.pose.yaw_offseter.filtered_stat.n > _POSE_OFFSET_MIN_COUNT
    self.blink = DriverBlink()
    self.awareness = 1.
    self.awareness_active = 1.
    self.driver_distracted = False
    self.driver_distraction_filter = FirstOrderFilter(0., _DISTRACTED_FILTER_TS, DT_DMON)
    self.face_detected = False
    self.terminal_alert_cnt = 0
    self.step_change = 0.
    self.active_monitoring_mode = True
    self.threshold_prompt = _DISTRACTED_PROMPT_TIME_TILL_TERMINAL / _DISTRACTED_TIME

    self.is_rhd_region = False
    self.is_rhd_region_checked = False

    self._set_timers(active_monitoring=True)

  def _set_timers(self, active_monitoring):
    if self.active_monitoring_mode and self.awareness <= self.threshold_prompt:
      if active_monitoring:
        self.step_change = DT_CTRL / _DISTRACTED_TIME
      else:
        self.step_change = 0.
      return # no exploit after orange alert
    elif self.awareness <= 0.:
      return

    if active_monitoring:
      # when falling back from passive mode to active mode, reset awareness to avoid false alert
      if not self.active_monitoring_mode:
        self.awareness = self.awareness_active

      self.threshold_pre = _DISTRACTED_PRE_TIME_TILL_TERMINAL / _DISTRACTED_TIME
      self.threshold_prompt = _DISTRACTED_PROMPT_TIME_TILL_TERMINAL / _DISTRACTED_TIME
      self.step_change = DT_CTRL / _DISTRACTED_TIME
      self.active_monitoring_mode = True
    else:
      if self.active_monitoring_mode:
        self.awareness_active = self.awareness

      self.threshold_pre = _AWARENESS_PRE_TIME_TILL_TERMINAL / _AWARENESS_TIME
      self.threshold_prompt = _AWARENESS_PROMPT_TIME_TILL_TERMINAL / _AWARENESS_TIME
      self.step_change = DT_CTRL / _AWARENESS_TIME
      self.active_monitoring_mode = False

  def _is_driver_distracted(self, pose, blink):
    if not self.pose_calibrated:
      pitch_error = pose.pitch - _PITCH_NATURAL_OFFSET
      yaw_error = pose.yaw - _YAW_NATURAL_OFFSET
      # add positive pitch allowance
      if pitch_error > 0.:
        pitch_error = max(pitch_error - _PITCH_POS_ALLOWANCE, 0.)
    else:
      pitch_error = pose.pitch - self.pose.pitch_offseter.filtered_stat.mean()
      yaw_error = pose.yaw - self.pose.yaw_offseter.filtered_stat.mean()

    pitch_error *= _PITCH_WEIGHT
    pose_metric = np.sqrt(yaw_error**2 + pitch_error**2)

    if pose_metric > _METRIC_THRESHOLD:
      return DistractedType.BAD_POSE
    elif blink.left_blink>_BLINK_THRESHOLD and blink.right_blink>_BLINK_THRESHOLD:
      return DistractedType.BAD_BLINK
    else:
      return DistractedType.NOT_DISTRACTED

  def get_pose(self, driver_monitoring, cal_rpy, car_speed, op_engaged):
    # 10 Hz
    if len(driver_monitoring.faceOrientation) == 0 or len(driver_monitoring.facePosition) == 0:
      return

    self.pose.roll, self.pose.pitch, self.pose.yaw = head_orientation_from_descriptor(driver_monitoring.faceOrientation, driver_monitoring.facePosition, cal_rpy)
    self.blink.left_blink = driver_monitoring.leftBlinkProb * (driver_monitoring.leftEyeProb>_EYE_THRESHOLD)
    self.blink.right_blink = driver_monitoring.rightBlinkProb * (driver_monitoring.rightEyeProb>_EYE_THRESHOLD)
    self.face_detected = driver_monitoring.faceProb > _FACE_THRESHOLD and not self.is_rhd_region

    self.driver_distracted = self._is_driver_distracted(self.pose, self.blink)>0
    # first order filters
    self.driver_distraction_filter.update(self.driver_distracted)

    # update offseter
    # only update when driver is actively driving the car above a certain speed
    if self.face_detected and car_speed>_POSE_CALIB_MIN_SPEED and not op_engaged:
      self.pose.pitch_offseter.push_and_update(self.pose.pitch)
      self.pose.yaw_offseter.push_and_update(self.pose.yaw)

    self.pose_calibrated = self.pose.pitch_offseter.filtered_stat.n > _POSE_OFFSET_MIN_COUNT and \
                            self.pose.yaw_offseter.filtered_stat.n > _POSE_OFFSET_MIN_COUNT

    self._set_timers(self.face_detected)

  def update(self, events, driver_engaged, ctrl_active, standstill):
    if (driver_engaged and self.awareness > 0) or not ctrl_active:
      # reset only when on disengagement if red reached
      self.awareness = 1.
      self.awareness_active = 1.
      return events

    driver_attentive = self.driver_distraction_filter.x < 0.37
    awareness_prev = self.awareness

    if (driver_attentive and self.face_detected and self.awareness > 0):
      # only restore awareness when paying attention and alert is not red
      self.awareness = min(self.awareness + ((_RECOVERY_FACTOR_MAX-_RECOVERY_FACTOR_MIN)*(1.-self.awareness)+_RECOVERY_FACTOR_MIN)*self.step_change, 1.)
      # don't display alert banner when awareness is recovering and has cleared orange
      if self.awareness > self.threshold_prompt:
        return events

    # should always be counting if distracted unless at standstill and reaching orange
    if (not self.face_detected or (self.driver_distraction_filter.x > 0.63 and self.driver_distracted and self.face_detected)) and \
       not (standstill and self.awareness - self.step_change <= self.threshold_prompt):
      self.awareness = max(self.awareness - self.step_change, -0.1)

    alert = None
    if self.awareness <= 0.:
      # terminal red alert: disengagement required
      alert = 'driverDistracted' if self.active_monitoring_mode else 'driverUnresponsive'
      if awareness_prev > 0.:
        self.terminal_alert_cnt += 1
    elif self.awareness <= self.threshold_prompt:
      # prompt orange alert
      alert = 'promptDriverDistracted' if self.active_monitoring_mode else 'promptDriverUnresponsive'
    elif self.awareness <= self.threshold_pre:
      # pre green alert
      alert = 'preDriverDistracted' if self.active_monitoring_mode else 'preDriverUnresponsive'

    if alert is not None:
      events.append(create_event(alert, [ET.WARNING]))

    return events