145 lines
4.4 KiB
Python
145 lines
4.4 KiB
Python
# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import datetime
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WEEKDAYS = {'Monday': 0, 'Tuesday': 1, 'Wednesday': 2, 'Thursday': 3,
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'Friday': 4, 'Saturday': 5, 'Sunday': 6}
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class WeeklyRecurrence(object):
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"""Meetings occuring every week."""
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def __init__(self):
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pass
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def next_occurence(self, current_date_time, day):
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"""Return the date of the next meeting.
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:param ref_date: datetime object of meeting
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:param day: weekday the meeting is held on
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:returns: datetime object of the next meeting time
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"""
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weekday = WEEKDAYS[day]
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days_ahead = weekday - current_date_time.weekday()
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if days_ahead < 0: # target day already happened this week
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days_ahead += 7
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return current_date_time + datetime.timedelta(days_ahead)
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def rrule(self):
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return {'freq': 'weekly'}
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def __str__(self):
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return "Weekly"
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class BiWeeklyRecurrence(object):
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"""Meetings occuring on alternate weeks.
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Can be either on odd weeks or on even weeks
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"""
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def __init__(self, style='even'):
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self.style = style
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def next_occurence(self, current_date, day):
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"""Calculate the next biweekly meeting.
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:param current_date: the current date
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:param day: scheduled day of the meeting
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:returns: datetime object of next meeting
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"""
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nextweek_day = WeeklyRecurrence().next_occurence(current_date, day)
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if nextweek_day.isocalendar()[1] % 2:
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# ISO week is odd
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if self.style == 'odd':
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return nextweek_day
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else:
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# ISO week is even
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if self.style == 'even':
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return nextweek_day
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# If week doesn't match rule, skip one week
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return nextweek_day + datetime.timedelta(7)
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def rrule(self):
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return {'freq': 'weekly', 'interval': 2}
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def __str__(self):
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return "Every two weeks (on %s weeks)" % self.style
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class QuadWeeklyRecurrence(object):
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"""Meetings occuring every 4 weeks.
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A week number can be supplied to offset meetings
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"""
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def __init__(self, week=0):
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self.week = week
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def next_occurence(self, current_date, day):
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"""Calculate the next biweekly meeting.
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:param current_date: the current date
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:param day: scheduled day of the meeting
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:returns: datetime object of next meeting
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"""
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nextweek_day = WeeklyRecurrence().next_occurence(current_date, day)
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if nextweek_day.isocalendar()[1] % 4 == self.week:
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return nextweek_day
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# If week doesn't match rule, skip one week
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return self.next_occurence(nextweek_day + datetime.timedelta(7), day)
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def rrule(self):
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return {'freq': 'weekly', 'interval': 4}
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def __str__(self):
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return (
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"Every four weeks on week %d of the four week rotation"
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% self.week)
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class AdhocRecurrence(object):
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"""Meetings occuring as needed.
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Effectively this is a noop recurrance as next_occurance is always None
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"""
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def __init__(self):
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pass
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def next_occurence(self, current_date, day):
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"""Calculate the next adhoc meeting.
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:param current_date: the current date
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:param day: scheduled day of the meeting
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:returns: datetime object of next meeting
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"""
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return None
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def rrule(self):
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return {'freq': 'adhoc', 'interval': 0}
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def __str__(self):
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return "Occurs as needed, no fixed schedule."
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supported_recurrences = {
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'weekly': WeeklyRecurrence(),
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'biweekly-odd': BiWeeklyRecurrence(style='odd'),
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'biweekly-even': BiWeeklyRecurrence(),
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'quadweekly': QuadWeeklyRecurrence(week=0),
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'quadweekly-week-1': QuadWeeklyRecurrence(week=1),
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'quadweekly-week-2': QuadWeeklyRecurrence(week=2),
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'quadweekly-week-3': QuadWeeklyRecurrence(week=3),
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'quadweekly-alternate': QuadWeeklyRecurrence(week=2),
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'adhoc': AdhocRecurrence(),
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}
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