#Passive infrared motion sensor.

import pyb

class PIR(object):
  """Passive Infrared Motion Sensor driver.  Supports on/off through an output pin
     trigger reading as well as an interrupt callback on trigger high/low changes."""

  def __init__(self, power, trigger, callback = None):
    """Power and trigger pins, optional interrupt callback in the format
       of fun( bOnOff ).  This will be called whenever the trigger state
       changes."""
    self._power = pyb.Pin(power, pyb.Pin.OUT_PP)
    self._power.low()
    self._trigger = pyb.Pin(trigger, pyb.Pin.IN, pyb.Pin.PULL_DOWN)
    self.interrupt = callback

  def _on( self, aTF ) :
    """Turn device on/off"""
    if (aTF):
      oldon = self.inton
      self.inton = False  #Make sure interrupt is off while turning on power to avoid false callbacks.
      self._power.high()
      if (oldon):
        pyb.delay(200)     #Need to wait a bit after turning on to make sure we don't get false values.
        self.inton = oldon
    else:
      self._power.low()

  @property
  def on(self): return self._power.value()

  @on.setter
  def on(self, value): self._on(value)

  @property
  def trigger(self): return self._trigger.value()

  @property
  def interrupt(self): return self._interrupt

  @interrupt.setter
  def interrupt(self, func):
    self._interrupt = None;
    self._func = func
    if (aFunc != None):
      self._interrupt = pyb.ExtInt(self._trigger, pyb.ExtInt.IRQ_RISING_FALLING, pyb.Pin.PULL_DOWN, self._inthandler)
      self._inton = True

  def _inthandler(self, aLine):
    '''Function to handle interrupts and pass on to callback with on/off trigger state.'''
       call
    if (self._func != None):
      self._func(self.trigger)

  @property
  def inton(self): return self._inton

  @inton.setter
  def inton(self, value):
    self._inton = value
    if self._interrupt != None:
      if value :
        self._interrupt.enable()
      else:
        self._interrupt.disable()