from matplotlib import pyplot as plt

def f_theta(value, theta):
    if value <= theta:
        return 0

    return 1

def ideal_theta(theta, step, data):
    for point in data:
        if f_theta(point[0], theta) != point[1]:
            theta += step * (1 if theta <= point[0] else -1)

    return theta

def check_accuracy(theta, data):
    correct = 0

    for point in data:
        if f_theta(point[0], theta) == point[1]:
            correct += 1

    return correct / len(data)

def main():
    data = [(-100, 0), \
            (-20,  0), \
            (-40,  0), \
            (-67,  0), \
            (-10,  0), \
            (-5,   0), \
            (-21,  0), \
            (6,    1), \
            (20,   1), \
            (30,   1), \
            (70,   1), \
            (40,   1), \
            (10,   1)]

    theta = 20
    step = 100
    acc = 0

    while acc != 1:
        acc = check_accuracy(theta, data)
        theta = ideal_theta(20, step, data)
        step -= 0.5

        print("THETA: " + str(theta) + " STEP: " + str(step) + " ACC: " + str(acc))

    plt.hlines(0, -120, 120)

    blue = [point[0] for point in data if point[1] == 0]
    red = [point[0] for point in data if point[1] == 1]

    plt.plot(red, [0] * len(red), "bo")
    plt.plot(blue, [0] * len(blue), "ro")
    plt.plot([theta], [0], "go")

    plt.axis("off")

    plt.show()

if __name__ == "__main__":
    main()