#All the import statemets
import socket           #For UDP
import time             #For time
import android          #Android environment

#Our Droid entity
droid = android.Android()

#Some constants related to IP
UDP_IP = '192.168.1.45'
UDP_PORT = 8888
INET_ADDR = (UDP_IP,UDP_PORT)

#Some constants relating to direction.  These come from what I originally did on a keyboard
MoveForward= "q"
MoveBack = "z"
MoveStop = "a"
SteerLeft = "i"
SteerRight = "p"
SteerStop = "o"

#Some constants relating to thresholds.  Can be used to tune sensitivity
ForwardThresh = 0.3     #> This means you're tilted forward
BackwardThresh = -0.3   #< This means you're tilted backwards
LeftThresh = -0.4       #< This means you're tilted left
RightThresh = 0.4       #> This means you're tilted right

######################################
#Main part of the code
######################################

#Initialise the movement and steering state
MoveState = MoveStop
SteerState = SteerStop

#Use these variables to get the current state
CurrentMove = ""
CurrentSteer= ""

#Print port information
print "UDP target IP:", UDP_IP
print "UDP target port:", UDP_PORT

#Set up the socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

#Start sensing the Android sensors. Has a timer to allow the sensors to spark up
droid.startSensingTimed(1, 250)
time.sleep(1)

#Loop, detecting state and sending UDP
while True:
  #Use a try statement and add some error handling as well
  try:
    #Read the sensor state
    s1 = droid.sensorsReadOrientation().result

    #The result is a list made up of float variables.  Presented as a CSV on screen but we can mathematically manipulate

    #Set up the current states based upon the thresholds defined as constants - First for forward and back
    if s1[1] > ForwardThresh:
      CurrentMove = MoveForward
    elif s1[1] < BackwardThresh:
      CurrentMove = MoveBack
    else: CurrentMove = MoveStop

    #Now do it for left and right
    if s1[2] > RightThresh:
      CurrentSteer = SteerRight
    elif s1[2] < LeftThresh:
      CurrentSteer = SteerLeft
    else: CurrentSteer = SteerStop

    #So we've got the current state, now check with the overall logged state.  If it's changed, we do some UDP fun
    #First check the forward / back state
    if CurrentMove == MoveState:
      #Do nothing
      CurrentMove = CurrentMove    #Seems necessary other you get an error
    else:
      #Now we need to send UDP and update the overall state
      MoveState = CurrentMove
      sock.sendto(CurrentMove, INET_ADDR)
      print "Forward / back state changed.  Sent: " + CurrentMove

    #Now the left / right state
    if CurrentSteer == SteerState:
      #Do nothing
      CurrentSteer = CurrentSteer    #Seems necessary other you get an error
    else:
      #Now we need to send UDP and update the overall state
      SteerState = CurrentSteer
      sock.sendto(CurrentSteer, INET_ADDR)
      print "Left / right state changed.  Sent: " + CurrentSteer

      #Chill for a sec
      time.sleep(1)
  except Exception, err: #Handle exceptions
    #Write a screen with the error
    print "Got us an exception: " + str(err)
    time.sleep(1)