# Simple demo of continuous ADC conversion mode for channel 0 of the ADS1x15 ADC.
# Author: Tony DiCola
# License: Public Domain
import time

# Import the ADS1x15 module.
import Adafruit_ADS1x15

import threading

import socket
MCAST_GRP = '224.1.1.22'
MCAST_PORT = 1234
MULTICAST_TTL = 2
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, MULTICAST_TTL)

QUE_MAXLEN = 16
SAMPLES = 400
TIMEINTERVAL = 0.01
FRAMELEN = 8 + SAMPLES*2 + 2    # time 8 bytes, signal 400*2, checksun 2 bytes
queue = []
for i in range(QUE_MAXLEN):
    queue.append(bytearray(FRAMELEN))

queue_front = 0
queue_back = -1
queue_len = 0

def queue_pop():
    global queue_front
    global queue_len
    global queue

    queue_front += 1
    if queue_front >= QUE_MAXLEN:
        queue_front = 0
    queue_len -= 1

def queue_push():
    global queue_back
    global queue_len
    global queue

    queue_back += 1
    if queue_back >= QUE_MAXLEN:
        queue_back = 0
    queue_len += 1

cv = threading.Condition()

def sending():
    global queue_front
    global queue_back
    global queue_len
    global queue

    while True:
        cv.acquire()
        if queue_len == 0:
            cv.wait()
        if queue_len == 0:
            cv.release()
            continue

        frame = queue[queue_front]
        cv.release()

        # print("Frame ", frame[0])
        sock.sendto(frame, (MCAST_GRP, MCAST_PORT))

        cv.acquire()
        queue_pop()
        cv.release()

sendingThread = threading.Thread(target=sending)
sendingThread.start()

# Create an ADS1115 ADC (16-bit) instance.
adc = Adafruit_ADS1x15.ADS1115()

# Or create an ADS1015 ADC (12-bit) instance.
#adc = Adafruit_ADS1x15.ADS1015()

# Note you can change the I2C address from its default (0x48), and/or the I2C
# bus by passing in these optional parameters:
#adc = Adafruit_ADS1x15.ADS1015(address=0x49, busnum=1)

# Choose a gain of 1 for reading voltages from 0 to 4.09V.
# Or pick a different gain to change the range of voltages that are read:
#  - 2/3 = +/-6.144V
#  -   1 = +/-4.096V
#  -   2 = +/-2.048V
#  -   4 = +/-1.024V
#  -   8 = +/-0.512V
#  -  16 = +/-0.256V
# See table 3 in the ADS1015/ADS1115 datasheet for more info on gain.
GAIN = 1

# Start continuous ADC conversions on channel 0 using the previously set gain
# value.  Note you can also pass an optional data_rate parameter, see the simpletest.py
# example and read_adc function for more infromation.
adc.start_adc(0, gain=GAIN)
# Once continuous ADC conversions are started you can call get_last_result() to
# retrieve the latest result, or stop_adc() to stop conversions.

# Note you can also call start_adc_difference() to take continuous differential
# readings.  See the read_adc_difference() function in differential.py for more
# information and parameter description.

# Read channel 0 for 5 seconds and print out its values.
print('Reading ADS1x15 channel 0 for 5 seconds...')
start = time.time()
while True:
    # Read the last ADC conversion value and print it out.

    cv.acquire()
    queue_push()
    frame = queue[queue_back]
    cv.release()

    t0 = time.time()
    t = int(t0*1000.)
    for i in range(8):
        frame[i] = (t & 255)
        t >>= 8
    p = 8

    checksum = ((frame[0] + frame[1]*256) & 65535)
    checksum = ((checksum*3 + (frame[2] + frame[3]*256)) & 65535)
    checksum = ((checksum*3 + (frame[4] + frame[5]*256)) & 65535)
    checksum = ((checksum*3 + (frame[6] + frame[7]*256)) & 65535)

    for i in range(0, SAMPLES):
        t0 = time.time()
        value = adc.get_last_result()
        checksum = ((checksum*3 + value) & 65535)
        frame[p] = (value & 255)
        frame[p+1] = ((value>>8) & 255)
        p += 2
        # time.sleep(TIMEINTERVAL)
        dt = TIMEINTERVAL - (time.time() - t0)
        # print(dt)
        if dt > 0.:
            time.sleep(dt)

    frame[p] = (checksum & 255)
    frame[p+1] = ((checksum>>8) & 255)

    cv.acquire()
    cv.notify()
    cv.release()