pub fn voltage_from_adc(digi: f32) -> f32 {
    let vref = 2.048;
    (digi / 32_768.) * vref
}

fn lg(pt0: (f32, f32), pt1: (f32, f32), pt2: (f32, f32), X: f32) -> f32 {
    let mut result = 0.;

    let x = [pt0.0, pt1.0, pt2.0];
    let y = [pt0.1, pt1.1, pt2.1];

    for j in 0..3 {
        let mut c = 1.;
        for i in 0..3 {
            if j == i {
                continue;
            }
            c *= (X - x[i]) / (x[j] - x[i]);
        }
        result += y[j] * c;
    }

    result
}


fn ph_from_voltage(
    V: f32,
    temp: f32,
    cal_0: PhCalPt,
    cal_1: PhCalPt,
    cal_2: Option<PhCalPt>,
) -> f32 {
    let T = temp + 273.15;

    // todo: Temp compensation
    match cal_2 {
        // Model as a quadratic Lagrangian polynomial
        Some(c2) => {
            lg((cal_0.V, cal_0.pH), (cal_1.V, cal_1.pH), (c2.V, c2.pH), V)
        }
        // Model as a line
        None => {
            // a is the slope, pH / v.
            let a = (cal_1.pH - cal_0.pH) / (cal_1.V - cal_0.V);
            let b = cal_1.pH - a * cal_1.V;
            a * V + b
        }
    }
}

     pub fn read(&self) -> Result<f32, ads1x1x::Error> {
         let temp = temp_from_voltage(voltage_from_adc(block!(self.adc.read(&mut SingleA2))?));

         Ok(ph_from_voltage(
             voltage_from_adc(block!(self.adc.read(&mut DifferentialA0A1))?),
             temp,
              self.cal_1, self.cal_2, self.cal_3
         ))
     }

import time

import board
import busio
from anyleaf import PhSensor, CalPt, CalSlot


def main():
    i2c = busio.I2C(board.SCL, board.SDA)
    ph_sensor = PhSensor(i2c)

    # Can use 2 or 3-pt calibration.
    ph_sensor.calibrate_all(
        CalPt(0., 7., 25.), CalPt(-0.18, 4., 25.), CalPt(0.18, 10., 25.)
    )
    # Or, call these with the sensor in the appropriate buffer solution
    # ph_sensor.calibrate(CalSlot.One, 7.)
   #  ph_sensor.calibrate(CalSlot.Two, 4.)

    while True:
        pH = ph_sensor.read()
        print(f"pH: {pH}")
        time.sleep(.5)


if __name__ == "__main__":
    main()

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