events2ics

#!/usr/bin/env python

import argparse
import datetime
import re

EVENT_RE = '(\d+)/(\d+) (\d+)(:\d+)? (am|pm) to (\d+)(:\d+)? (am|pm) (.+) @ (.+)'
TIME_RE = '(\d+):(\d+) (am|pm)'
DATE_RE = '(\d+)/(\d+)'

'''
Convert a listing of events to an .ics calendar file.

Events filename format is:

  7/4 6 pm to 9:30 pm BBQ @ Home
'''

def convert_date(date, time):
    time_re = re.compile(TIME_RE)
    date_re = re.compile(DATE_RE)

    time_match = time_re.match(time)
    date_match = date_re.match(date)

    time_groups = time_match.groups()
    date_groups = date_match.groups()

    hours = int(time_groups[0])
    minutes = int(time_groups[1])
    if time_groups[2].lower() == 'pm':
        hours += 12

    year = datetime.datetime.now().year
    month = int(date_groups[0])
    day = int(date_groups[1])

    return '%04d%02d%02dT%02d%02d00' % (year, month, day, hours, minutes)

def print_calendar_header():
    print('BEGIN:VCALENDAR')
    print('PRODID:-//michaelgalloy//michaelgalloy.com 1.0//EN')
    print('VERSION:2.0')

def print_calendar_footer():
    print('END:VCALENDAR')

def print_event(date, start_time, end_time, timezone, title, location):
    '''An event looks like:

         BEGIN:VEVENT
         DTSTART:20170603T160000
         DTEND:20170603T210000
         SUMMARY:Backyard BBQ
         CATEGORIES:
         DESCRIPTION:For details, click here: http://www.evite.com/event/0111CUTIWD324UWNAEPHITJHYROW7A?gid=020E64BWSS4O6I2RQEPHI5E4S7EVY4
         LOCATION:Katie & Dave's Backyard 609 Marine St Boulder CO 80302
         END:VEVENT'''
    print('BEGIN:VEVENT')
    print('DTSTART;TZID=%s:%s' % (timezone, convert_date(date, start_time)))
    print('DTEND;TZID=%s:%s' % (timezone, convert_date(date, end_time)))
    print('SUMMARY:%s' % title)
    print('LOCATION:%s' % location)
    print('END:VEVENT')

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='convert event listing to ics file')
    parser.add_argument('events', help='events filename')
    parser.add_argument('-t', '--timezone', help='timezone, i.e., America/Denver', default='America/Denver')
    args = parser.parse_args()

    event_re = re.compile(EVENT_RE)

    print_calendar_header()
    with open(args.events, 'r') as events_file:
        for event_line in events_file:
            event_match = event_re.match(event_line)
            if event_match:
                groups = event_match.groups()
                date = '%s/%s' % (groups[0], groups[1])
                start_time = '%s%s %s' % (groups[2], groups[3] if groups[3] is not None else ':00', groups[4])
                end_time = '%s%s %s' % (groups[5], groups[6] if groups[6] is not None else ':00', groups[7])
                title = groups[8]
                location = groups[9]
                print_event(date, start_time, end_time, args.timezone, title, location)
    print_calendar_footer()