import pyvisa
import os.path
import sys
import os
import csv
import datetime
import bme280
import time
import smbus2

NUMMEAS = 1
NUMSAMPLES = 4
NUMCHANNELS = 7
NULLINGCHANNEL = 7
SCANNERSLOT = 2
AUTOZERO = 1
ENVMON = 0
BASESAVENAME = "Prod_VoltageBankLog_Ch"

bus = smbus2.SMBus(1)
calibration_params = bme280.load_calibration_params(bus, 0x76)

rm = pyvisa.ResourceManager()
inst2 = rm.open_resource('GPIB0::18::INSTR') # Meter
inst1 = rm.open_resource('GPIB0::9::INSTR')  # Scanner

def openCloseGPIB(openClose):
    global GPIB
    global inst1
    global inst2
    if openClose == "close":
        inst1.close()
        inst2.close()
    elif openClose == "open":
        inst2 = rm.open_resource('GPIB0::18::INSTR') # Meter
        inst1 = rm.open_resource('GPIB0::9::INSTR')  # Scanner

def getEnvironment(instObj, i2cbus):
    value = instObj.sample(i2cbus, 0x76, calibration_params)
    return value

def closeChannel(instObj, scannerCardSlot, channel):
    print("----- Closing channel: "+str(f"{channel:02}")+" on slot: "+str(scannerCardSlot)+" -----")
    instObj.write("CLOSE "+str(scannerCardSlot)+str(f"{channel:02}"))  

def openChannel(instObj, scannerCardSlot, channel = 9):
    if channel >= 9:
        print("----- Opening All Channels -----")
        instObj.write("RESET")
    else:
        print("----- Opening channel: "+str(f"{channel:02}")+" on slot: "+str(scannerCardSlot)+" -----")
        instObj.write("OPEN "+str(scannerCardSlot)+str(f"{channel:02}"))  

def readNVM(instObj):
    # dummy reading for auto range
    instObj.write("MOD=VDC:RAN=AUTO:NI=5")# DCV, AUTO RANGE, 5.5 digits
    instObj.write("MEAS=SI")
    time.sleep(2)
    instObj.write("NI=8")# 8.5 digits
    output = []
    # Set amount of samples
    for i in range(NUMSAMPLES):
        time.sleep(1)   
        instObj.write("MEAS=SI") 
        time.sleep(110*(AUTOZERO+1))
        out = instObj.read()
        print(out)
        output.append(instObj.read())
    output = instObj.read().split(' ')
    output = map(float, output)
    return (list(output))

def getMeanSTDev(values):
    mean = sum(values)/len(values)
    variance = sum([(x - mean) ** 2 for x in values]) / (len(values) - 1)
    stddev = variance ** 0.5
    #print(mean,variance,stddev)
    return mean, stddev

# NVM Setup
inst2.write("DIS=ON")
inst2.write("HISTORY,CLEAR") 
time.sleep(3)
inst2.write("MOD=VDC:RAN=10:NI=8")# 10VDC RANGE, 8.5 digits
inst2.write("MEAS=CON") 
inst2.write("DELI=END")           # Delimeter set to END
inst2.write("OUTPUT,GP-IB,ON")    # Sets output via GPIB
inst2.write("DR=OFF")             # Turns Drift Correction OFF
if AUTOZERO:
    inst2.write("DR=ON")          # Turns Drift Correction ON

# Scanner setup
inst1.write("RESET") 
inst1.write("CRESET 2")  
inst1.write("CRESET 3") 

readings = []

for i in range(NUMCHANNELS):
    # get the nulled channel value
    closeChannel(inst1, SCANNERSLOT, i+10)
    print("NULLING...")
    nullMeanStatsA   = []
    nullStddevStatsA = []
    for nulling in range(NUMMEAS):
        nullReadingsA = readNVM(inst2)
        nullMeanA, nullStddevA = getMeanSTDev(nullReadingsA)
        nullMeanStatsA.append(nullMeanA)
        nullStddevStatsA.append(nullStddevA)
        nullMeanStats   = []
    nullMeanStatsB   = []
    nullStddevStatsB = []
    openChannel(inst1, SCANNERSLOT, i+10)

    closeChannel(inst1, SCANNERSLOT, i)
    print("REVERSING...")
    for nulling in range(NUMMEAS):
        nullReadingsB = readNVM(inst2)
        nullMeanB, nullStddevB = getMeanSTDev(nullReadingsB)
        nullMeanStatsB.append(nullMeanB)
        nullStddevStatsB.append(nullStddevB)
    openChannel(inst1, SCANNERSLOT, i)

    nullMeanStats = nullMeanStatsB - nullMeanStatsA

    # read value
    closeChannel(inst1, SCANNERSLOT, i)
    print("READING VALUE...")
    MeanStats   = []
    StddevStats = []
    for nulling in range(NUMMEAS):
        Readings = readNVM(inst2)
        Mean, Stddev = getMeanSTDev(Readings)
        MeanStats.append(Mean)
        StddevStats.append(Stddev)
    openChannel(inst1, SCANNERSLOT, i)

    # compensate for nulling
    meanNull, x          = getMeanSTDev(nullMeanStats)
    x, stddevNull        = getMeanSTDev(nullMeanStats)
    meanMeas, x          = getMeanSTDev(MeanStats)
    stddevMeas, x        = getMeanSTDev(StddevStats)
    meanCompensated      = meanMeas - meanNull
    stddevCompensated    = stddevMeas + stddevNull
    d     = datetime.datetime.now()
    dx    = d - datetime.timedelta(microseconds=d.microsecond)
    data  = getEnvironment(bme280, bus)
    fields=[dx.strftime("%d-%m-%y %H:%M:%S"),i+1,round(meanNull,10),round(stddevNull,10),round(meanMeas,10),round(stddevMeas,10),round(meanCompensated,10),round(stddevCompensated,10),round(data.humidity,2),round(data.temperature,2),round(data.pressure,2)]
    print(fields)

    if not os.path.exists("data/"):
        os.makedirs("data/")
    if not os.path.exists("data/"+BASESAVENAME+str(i+1)+".csv"):
        with open("data/"+BASESAVENAME+str(i+1)+".csv", 'w') as file:
            file.writelines("DateTime;Channel;NullingMean;NullingStddev;MeasuredMean;MeasuredStddev;CompensatedMean;CompensatedStddev;EnvHumidity;EnvTemperature;EnvPressure")
    else:
        with open("data/"+BASESAVENAME+str(i+1)+".csv", 'a') as f:
            writer = csv.writer(f)
            writer.writerow(fields)
#inst1.write(":DISP:ENAB 0")
inst2.write("A1,''X")
#inst1.write(":DISP:TEXT:STAT 0")
GPIB.close()