"""
Listen to serial, return most recent numeric values
Lots of help from here:
http://stackoverflow.com/questions/1093598/pyserial-how-to-read-last-line-sent-from-serial-device
"""
from threading import Thread

import time
import serial
import struct


status = [0, 23, 23, 0, 0, 0]

oven_connected = False

profile = [
  150,
  200,
  217,
  260,
  480,
  1,
  2,
  1,
  2,
  -1,
  -6,
  60,
  180,
  60,
  150,
  20,
  40]

PI_TS_MIN = 0
PI_TS_MAX = 1
PI_TL = 2
PI_TP = 3
PI_TIME_MAX = 4

PI_TS_RAMP_UP_MIN = 5
PI_TS_RAMP_UP_MAX = 6
PI_TP_RAMP_UP_MIN = 5
PI_TP_RAMP_UP_MAX = 6
PI_RAMP_DOWN_MIN = 7
PI_RAMP_DOWN_MAX = 8

PI_TS_DURATION_MIN = 9
PI_TS_DURATION_MAX = 10
PI_TL_DURATION_MIN = 11
PI_TL_DURATION_MAX = 12
PI_TP_DURATION_MIN = 13
PI_TP_DURATION_MAX = 14

def recv_config(ser):
  global profile
  ser.write(chr(255))
  ser.flush()
  t = ser.read(30)
  profile = struct.unpack("hhhhhhhhhhhhhhhhh", t)
  ser.flushInput()


def receiving(ser):
  global status
  try:
    time.sleep(2)
    recv_config(ser)
  except Exception, e:
    print e
    pass

  while 1:
    ser.write(chr(254))
    ser.flush()
    status = struct.unpack("hhhhhb", ser.read(11))
    ser.flushInput()


class SerialData(object):
    def __init__(self, init=50):
        try:
            self.ser = ser = serial.Serial(
                port='/dev/ttyUSB0',
                baudrate=9600, timeout=2)
        except serial.serialutil.SerialException:
            #no serial connection
            self.ser = None
        else:
            Thread(target=receiving, args=(self.ser,)).start()

    def next(self):
        global status
        if not self.ser:
            return status[1]

        try:
            return status[1]
        except Exception:
            pass

    def send_config(self):
        if not self.ser:
            return

        global profile
        self.ser.write(struct.pack("hhhhhhhhhhhhhhhhh", profile))

    def send_start(self):
        if not self.ser:
            return False

        self.ser.write(chr(251))
        return True

    def connected(self):
        return self.ser != None

    def __del__(self):
        if self.ser:
            self.ser.close()

if __name__=='__main__':
    s = SerialData()
    for i in range(500):
        time.sleep(1)
        print s.next()