from gpiozero import MCP3008
import time
import math

adc = MCP3008(channel=0)
count = 0
"""
volts key pairs created with the below + known values from datasheet
    # create voltage divider for use with MCP3008 ADC
    def volt_div(r1, r2, vIn):
        vOut = (vIn * r2)/(r1 + r2)
        return round(vOut,3)

    # calculate vOut values for each wind direction using known resistances from datasheet, 3.3 V from RPi and 4.7K ohm resistor

    resistances = [33000, 6570, 8200, 891, 1000, 688, 2200, 1410, 390, 3140, 16000, 14120, 120000, 42120, 64900, 21880]

    for i in range(len(resistances)):
        print(resistances[i],volt_div(4700, resistances[i], 3.3))

4.7K resistor
volts = {0.4: "0.0 N",
        1.4: "22.5 NNE",
        1.2: "45.0 NE",
        2.8: "67.5 ENE",
        2.7: "90.0 E",
        2.9: "112.5 ESE",
        2.2: "135.0 SE",
        2.5: "157.5 SSE",
        1.8: "180.0 S",
        2.0: "202.5 SSW",
        0.7: "225.0 SW",
        0.8: "247.5 WSW",
        0.1: "270.0 W",
        0.3: "292.5 WNW",
        0.2: "315.0 NW",
        0.6: "337.5 NNW"}
"""
# 5K resistor
volts = {1.87: 0.0,
        2.04: 22.5,
        0.79: 45.0,
        0.80: 45.0,
        0.88: 67.5,
        0.13: 90.0,
        0.36: 112.5,
        0.24: 135.0,
        0.62: 157.5,
        0.44: 180.0,
        1.44: 202.5,
        1.27: 225.0,
        2.81: 247.5,
        2.76: 270.0,
        2.91: 292.5,
        2.31: 315.0,
        2.59: 337.5}

def getAverage(angles):
    sinSum = 0.0
    cosSum = 0.0

    for angle in angles:
        r = math.radians(angle)
        sinSum += math.sin(r)
        cosSum += math.cos(r)

    flen = float(len(angles))
    s = sinSum / flen
    c = cosSum / flen
    arc = math.degrees(math.atan(s / c))
    average = 0.0

    if s > 0 and c > 0:
        average = arc
    elif c <0:
        average = arc + 180
    elif s < 0 and c > 0:
        average = arc + 360

    return 0.0 if average == 360 else average

def getValue(length=5):
    data = []
    startTime = time.time()

    while time.time() - startTime <= length:
        wind = round(adc.value*3.3,2)
        if not wind in volts: # keep only good measurements
            print("Unknown value: " + str(wind))
        else:
            data.append(volts[wind])
            
    return getAverage(data)

getValue()