"""calculates your updates-per-second"""

import time


class Updatefreq:
    """make one of these, call update() on it as much as you want,
    and then float() or str() the object to learn the updates per second.

    the samples param to __init__ specifies how many past updates will
    be stored.  """

    def __init__(self, samples=20):
        self.times = [0]
        self.samples = samples

    def update(self):
        """call this every time you do an update"""
        self.times = self.times[-self.samples:]
        self.times.append(time.time())

    def __float__(self):
        """a cheap algorithm, for now, which looks at the first and
        last times only"""

        try:
            hz = len(self.times) / (self.times[-1] - self.times[0])
        except ZeroDivisionError:
            return 0.0
        return hz

    def __str__(self):
        return "%.2fHz" % float(self)