import smbus2
from smbus2 import SMBusWrapper, SMBus, i2c_msg
from collections import namedtuple 
from functools import partial
#import Adafruit_PureIO.smbus as adabus
from time import sleep, asctime,time
import json
from copy import copy
import requests
import os.path

DEVICE_BUS = 1
DEVICE_ADDR = 0x58
#print bus.write_byte_datadata(DEVICE_ADDR, 0x00, 0x01)
#self._i2c_read_words_from_cmd([0x36, 0x82], 0.01, 3)

Sgp30Cmd = namedtuple("Sgp30Cmd",["commands","replylen","waittime"])
GET_SERIAL=Sgp30Cmd([0x36, 0x82],6,10)
GET_FEATURES=Sgp30Cmd([0x20, 0x15],2,2)
IAQ_INIT=Sgp30Cmd([0x20, 0x03],0,10)
IAQ_MEASURE=Sgp30Cmd([0x20, 0x08],6,12)
IAQ_SELFTEST=Sgp30Cmd([0x20, 0x32],3,520)
GET_BASELINE=Sgp30Cmd([0x20, 0x15],6,120)
SET_BASELINE=Sgp30Cmd([0x20, 0x1e],0,10)

Sgp30Answer = namedtuple("Sgp30Answer",["data","raw"])

def read_write(cmd,bus,addr=DEVICE_ADDR):
    write = i2c_msg.write(addr,cmd.commands)
    if cmd.replylen <= 0 :
       bus.i2c_rdwr(write)
    else:
        read = i2c_msg.read(addr,cmd.replylen)
        bus.i2c_rdwr(write) 
        sleep(waittime/1000.0)
        bus.i2c_rdwr(read)
        r = list(read)
        answer = [i<<8 | j for i,j in zip(r[0::3],r[1::3])]
        return answer
    
with SMBusWrapper(1) as bus:
    rw=partial(read_write,bus=bus)
    print(rw(GET_FEATURES))
    print(rw(GET_SERIAL))
    print(rw(IAQ_INIT))
    #print(rw(IAQ_SELFTEST,sleep_time=.1))
    for i in range(600):
        print( "CO_2eq: %d ppm, TVOC: %d"%tuple( rw(IAQ_MEASURE,sleep_time=.1)))
        sleep(2)
    

bus.close()