import re
from datetime import datetime

import pytz

from pyrfc3339.utils import FixedOffset


def parse(timestamp, utc=False, produce_naive=False):
    '''
    Parse an :RFC:`3339`-formatted timestamp and return a
    `datetime.datetime`.

    If the timestamp is presented in UTC, then the `tzinfo` parameter of the
    returned `datetime` will be set to `pytz.utc`.

    >>> parse('2009-01-01T10:01:02Z')
    datetime.datetime(2009, 1, 1, 10, 1, 2, tzinfo=<UTC>)

    Otherwise, a `tzinfo` instance is created with the appropriate offset, and
    the `tzinfo` parameter of the returned `datetime` is set to that value.

    >>> parse('2009-01-01T14:01:02-04:00')
    datetime.datetime(2009, 1, 1, 14, 1, 2, tzinfo=<UTC-04:00>)

    However, if `parse()`  is called with `utc=True`, then the returned
    `datetime` will be normalized to UTC (and its tzinfo parameter set to
    `pytz.utc`), regardless of the input timezone.

    >>> parse('2009-01-01T06:01:02-04:00', utc=True)
    datetime.datetime(2009, 1, 1, 10, 1, 2, tzinfo=<UTC>)

    The input is strictly required to conform to :RFC:`3339`, and appropriate
    exceptions are thrown for invalid input.

    >>> parse('2009-01-01T06:01:02')
    Traceback (most recent call last):
    ...
    ValueError: timestamp does not conform to RFC 3339

    >>> parse('2009-01-01T25:01:02Z')
    Traceback (most recent call last):
    ...
    ValueError: hour must be in 0..23

    '''

    parse_re = re.compile(r'''^(?:
                         (?:
                              (?P<date_fullyear>[0-9]{4})
                              \-
                              (?P<date_month>[0-9]{2})
                              \-
                              (?P<date_mday>[0-9]{2})
                          )
                          T
                          (?:
                              (?:
                                  (?P<time_hour>[0-9]{2})
                                  \:
                                  (?P<time_minute>[0-9]{2})
                                  \:
                                  (?P<time_second>[0-9]{2})
                                  (?P<time_secfrac>(?:\.[0-9]{1,}))?)
                                  (?P<time_offset>
                                      (?:
                                          Z
                                          |
                                          (?P<time_numoffset>
                                              (?P<time_houroffset>
                                                  (?:\+|\-)[0-9]{2}
                                              )
                                              \:
                                              (?P<time_minuteoffset>[0-9]{2})
                                          )
                                      )
                                  )
                          )
                        )$''',
                   re.I | re.X)

    match = parse_re.match(timestamp)

    if match is not None:
        if match.group('time_offset') in ["Z", "z", "+00:00", "-00:00"]:
            if produce_naive is True:
                tzinfo = None
            else:
                tzinfo = pytz.utc
        else:
            if produce_naive is True:
                raise ValueError("cannot produce a naive datetime from " +
                                 "a local timestamp")
            else:
                tzinfo = FixedOffset(int(match.group('time_houroffset')),
                                     int(match.group('time_minuteoffset')))

        secfrac = match.group('time_secfrac')
        if secfrac is None:
            microsecond = 0
        else:
            microsecond = int(round(float(secfrac) * 1000000))

        dt_out = datetime(year=int(match.group('date_fullyear')),
                      month=int(match.group('date_month')),
                      day=int(match.group('date_mday')),
                      hour=int(match.group('time_hour')),
                      minute=int(match.group('time_minute')),
                      second=int(match.group('time_second')),
                      microsecond=microsecond,
                      tzinfo=tzinfo)

        if utc:
            dt_out = dt_out.astimezone(pytz.utc)

        return dt_out
    else:
        raise ValueError("timestamp does not conform to RFC 3339")

@@ -1470,1438 +1470,324 @@
 %5E(?:
-%0A                         (?:%0A                              (?P%3Cdate_fullyear%3E%5B0-9%5D%7B4%7D)%0A                              %5C-%0A                              (?P%3Cdate_month%3E%5B0-9%5D%7B2%7D)%0A                              %5C-%0A                              (?P%3Cdate_mday%3E%5B0-9%5D%7B2%7D)%0A                          )%0A                          T%0A                          (?:%0A                              (?:%0A                                  (?P%3Ctime_hour%3E%5B0-9%5D%7B2%7D)%0A                                  %5C:%0A                                  (?P%3Ctime_minute%3E%5B0-9%5D%7B2%7D)%0A                                  %5C:%0A                                  (?P%3Ctime_second%3E%5B0-9%5D%7B2%7D)%0A                                  (?P%3Ctime_secfrac%3E(?:%5C.%5B0-9%5D%7B1,%7D))?)%0A                                  (?P%3Ctime_offset%3E%0A                                      (?:%0A                                          Z%0A                                          %7C%0A                                          (?P%3Ctime_numoffset%3E%0A                                              (?P%3Ctime_houroffset%3E%0A                                                  (?:%5C+%7C%5C-)%5B0-9%5D%7B2%7D%0A                                              )%0A                                              %5C:%0A                                              (?P%3Ctime_minuteoffset%3E%5B0-9%5D%7B2%7D)%0A                                          )%0A                                      )%0A                                  )%0A                          )%0A                        
+(?:(?P%3Cdate_fullyear%3E%5B0-9%5D%7B4%7D)%5C-(?P%3Cdate_month%3E%5B0-9%5D%7B2%7D)%5C-(?P%3Cdate_mday%3E%5B0-9%5D%7B2%7D))T(?:(?:(?P%3Ctime_hour%3E%5B0-9%5D%7B2%7D)%5C:(?P%3Ctime_minute%3E%5B0-9%5D%7B2%7D)%5C:(?P%3Ctime_second%3E%5B0-9%5D%7B2%7D)(?P%3Ctime_secfrac%3E(?:%5C.%5B0-9%5D%7B1,%7D))?)(?P%3Ctime_offset%3E(?:Z%7C(?P%3Ctime_numoffset%3E(?P%3Ctime_houroffset%3E(?:%5C+%7C%5C-)%5B0-9%5D%7B2%7D)%5C:(?P%3Ctime_minuteoffset%3E%5B0-9%5D%7B2%7D)))))
 )$''

Reformat regular expression.