Generate office hours

officehours.py

import itertools
from datetime import time, timedelta, datetime

OFFICE_OPEN = time(8, 0, 0)
OFFICE_CLOSE = time(16, 0, 0)


def isofficehour(dt):
    t = dt.time()
    if dt.weekday() in (5,6):  # Weekend
        return False
    return OFFICE_OPEN <= t and t <= OFFICE_CLOSE


def datetimes(starting):
    for i in itertools.count():
        t = starting.time()
        if (i == 0 and t < OFFICE_OPEN) or i != 0:
            t = OFFICE_OPEN
        yield starting.replace(hour=t.hour, minute=t.minute, second=t.second) + timedelta(days=i)


def officehours(starting=None):
    if starting is None:
        starting = datetime.now()
    return itertools.ifilter(isofficehour, datetimes(starting))


def test():
    """
    If the starting time is within office hour, pick the same day

        >>> from datetime import datetime
        >>> officehours(starting=datetime(2016, 4, 4, 13, 45, 20)).next()
        datetime.datetime(2016, 4, 4, 13, 45, 20)

    If the starting time is after office hours, pick the next day

        >>> officehours(starting=datetime(2016, 4, 4, 6, 30)).next()
        datetime.datetime(2016, 4, 4, 8, 0)

    If the starting time is before office hours, pick the same day

        >>> officehours(starting=datetime(2016, 4, 4, 16, 0, 1)).next()
        datetime.datetime(2016, 4, 5, 8, 0)


    Let's step through an officehour generator, starting with friday

        >>> someday = datetime(2016, 4, 8, 6, 36)
        >>> someday.strftime("%A"), someday.time().isoformat()
        ('Friday', '06:36:00')

    Friday morning is before office hours so the next() will pick same day

        >>> gen = officehours(starting=someday)
        >>> dt = gen.next()
        >>> dt.strftime("%A"), dt.time().isoformat()
        ('Friday', '08:00:00')

    The next officehour will be monday because weekends are closed

        >>> dt = gen.next()
        >>> dt.strftime("%A"), dt.time().isoformat()
        ('Monday', '08:00:00')

    Next will be tuesday, because tuesday is nothing special

        >>> dt = gen.next()
        >>> dt.strftime("%A"), dt.time().isoformat()
        ('Tuesday', '08:00:00')

    """

if __name__ == '__main__':
    import doctest
    doctest.testmod()