67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
import datetime
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from timezone_field.backends import get_tz_backend
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def normalize_standard(tztuple):
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"""Normalize timezone names by replacing special characters with space.
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For proper sorting, using spaces makes comparisons more consistent.
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:param str tztuple: tuple of timezone and representation
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"""
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return tztuple[1].translate(str.maketrans({"-": " ", "_": " "}))
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def normalize_gmt(tztuple):
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"""Normalize timezone GMT names for sorting.
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For proper sorting, using GMT values as a positive or negative number.
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:param str tztuple: tuple of timezone and representation
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"""
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gmt = tztuple[1].split()[0]
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cmp = gmt.replace("GMT", "").replace(":", "")
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return int(cmp)
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def standard(timezones):
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"""
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Given a list of timezones (either strings of timezone objects),
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return a list of choices with
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* values equal to what was passed in
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* display strings as the timezone name without underscores
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"""
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choices = []
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for tz in timezones:
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tz_str = str(tz)
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choices.append((tz, tz_str.replace("_", " ")))
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return sorted(choices, key=normalize_standard)
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def with_gmt_offset(timezones, now=None, use_pytz=None):
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"""
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Given a list of timezones (either strings of timezone objects),
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return a list of choices with
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* values equal to what was passed in
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* display strings formated with GMT offsets and without
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underscores. For example: "GMT-05:00 America/New York"
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* sorted by their timezone offset
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"""
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tz_backend = get_tz_backend(use_pytz)
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now = now or datetime.datetime.now(tz_backend.utc_tzobj)
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_choices = []
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for tz in timezones:
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tz_str = str(tz)
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now_tz = now.astimezone(tz_backend.to_tzobj(tz_str))
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delta = now_tz.replace(tzinfo=tz_backend.utc_tzobj) - now
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display = "GMT{sign}{gmt_diff} {timezone}".format(
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sign="+" if delta == abs(delta) else "-",
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gmt_diff=str(abs(delta)).zfill(8)[:-3],
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timezone=tz_str.replace("_", " "),
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)
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_choices.append((delta, tz, display))
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_choices.sort(key=lambda x: x[0])
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choices = [(one, two) for zero, one, two in _choices]
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return sorted(choices, key=normalize_gmt)
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