dayshift: get the date of the next or previous occurrence of a weekday

dayshift.py

#!/usr/local/bin/python3
"""
Print the date of the next or last specified weekday.

Usage:
    dayshift next <weekday> [--format=<fmt> --inline]
    dayshift last <weekday> [--format=<fmt> --inline]

Options:
    --format=<fmt>, -f <fmt>    A strftime format string
                                [default: %Y-%m-%d]
    --inline, -i                Omit trailing newline

"""
from docopt import docopt
from datetime import date, timedelta

WEEKDAYS = {'mon': 0, 'tue': 1, 'wed': 2, 'thu': 3,
            'fri': 4, 'sat': 5, 'sun': 6}

args = docopt(__doc__)
starting_offset = 2 if args['next'] else -2
start_date = date.today() + timedelta(starting_offset)
start_integer = start_date.weekday()
target_integer = WEEKDAYS[args['<weekday>'][:3].lower()]

if args['next']:
    offset = target_integer - start_integer
elif args['last']:
    offset = start_integer - target_integer

if offset <= 0:
    offset += 7

if args['last']:
    offset /= -1    # Make the offset negative

target_date = start_date + timedelta(offset)
ending = '' if args['--inline'] else '\n'
print(target_date.strftime(args['--format']), end=ending)