import numpy as np

class SimpleHighPassFilter():
    def __init__(self, cutoffFrequency, sampleTime, amp):
        self.pole = np.exp(-2*np.pi*(cutoffFrequency)*(sampleTime))
        self.alpha = self.pole
        self.gamma = (1+self.pole)/2
        self.isFirstTime = True
        self.amp = amp

    def getFilteredSample(self, input):
        if (self.isFirstTime):
            self.isFirstTime = False
            self.outputPast = 0
            self.inputPast = input
        output = self.alpha * self.outputPast + self.gamma * (input - self.inputPast)
        self.outputPast = output
        self.inputPast = input
        return output*self.amp