import numpy as np
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
from tqdm import tqdm

# wrapper class for an interval
# readability is more important than efficiency, so I won't use many tricks
class Interval:
    # [@left, @right)
    def __init__(self, left, right):
        self.left = left
        self.right = right

    # whether a point is in this interval
    def contain(self, x):
        return self.left <= x < self.right

    # length of this interval
    def size(self):
        return self.right - self.left

# domain of the square wave, [0, 2)
DOMAIN = Interval(0.0, 2.0)

# square wave function
def square_wave(x):
    if 0.5 < x < 1.5:
        return 1
    return 0

# get @n samples randomly from the square wave
def sample(n):
    samples = []
    for i in range(0, n):
        x = np.random.uniform(DOMAIN.left, DOMAIN.right)
        y = square_wave(x)
        samples.append([x, y])
    return samples