Generates list of dates at specific intervals before a given date then creates an *.ics file with those dates as events

seths_tool

from datetime import datetime, timedelta
from icalendar import Calendar, Event
import tempfile, os


# lists of date itervals specific to each type of schedule item
milestones_symphony = [7, 14, 28, 112]
milestones_opera    = [7, 14, 21, 28]
milestones_other    = [7, 28, 364]

# pass in one of the lists
def calculate_milestones(input_date, date_intervals_list):

    dates = []

    for interval in date_intervals_list:
        dates.append(input_date - timedelta(days=interval))

    return dates


def create_calendar(input_dates):

    # so we make a calendar to which we add all the events
    cal = Calendar()

    # adds a new event to the calendar for each date in the list
    for each_date in input_dates:
        event = Event()
        event.add('dtstart', each_date)
        cal.add_component(event)

    # makes a temporary file to export the calendar to
    directory = tempfile.mkdtemp()
    f = open(os.path.join(directory, 'milestones.ics'), 'wb')
    f.write(cal.to_ical())
    f.close()

    # prints the location of the ics file
    print(directory)


my_milestones = calculate_milestones(datetime.now(), milestones_other)

for ms in my_milestones:
  print(ms)

create_calendar(my_milestones)