# -*- coding:iso-8859-1 -*-
"""
This module offers a generic date/time string parser which is able to parse
most known formats to represent a date and/or time.

Additional resources about date/time string formats can be found below:

- `A summary of the international standard date and time notation
  <http://www.cl.cam.ac.uk/~mgk25/iso-time.html>`_
- `W3C Date and Time Formats <http://www.w3.org/TR/NOTE-datetime>`_
- `Time Formats (Planetary Rings Node) <http://pds-rings.seti.org/tools/time_formats.html>`_
- `CPAN ParseDate module
  <http://search.cpan.org/~muir/Time-modules-2013.0912/lib/Time/ParseDate.pm>`_
- `Java SimpleDateFormat Class
  <https://docs.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html>`_
"""
from __future__ import unicode_literals

import datetime
import string
import time
import collections
from io import StringIO

from six import text_type, binary_type, integer_types

from . import relativedelta
from . import tz

__all__ = ["parse", "parserinfo"]


class _timelex(object):

    def __init__(self, instream):
        if isinstance(instream, text_type):
            instream = StringIO(instream)

        self.instream = instream
        self.wordchars = ('abcdfeghijklmnopqrstuvwxyz'
                          'ABCDEFGHIJKLMNOPQRSTUVWXYZ_'
                          'ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ'
                          'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ')
        self.numchars = '0123456789'
        self.whitespace = ' \t\r\n'
        self.charstack = []
        self.tokenstack = []
        self.eof = False

    def get_token(self):
        """
        This function breaks the time string into lexical units (tokens), which
        can be parsed by the parser. Lexical units are demarcated by changes in
        the character set, so any continuous string of letters is considered one
        unit, any continuous string of numbers is considered one unit.

        The main complication arises from the fact that dots ('.') can be used
        both as separators (e.g. "Sep.20.2009") or decimal points (e.g.
        "4:30:21.447"). As such, it is necessary to read the full context of
        any dot-separated strings before breaking it into tokens; as such, this
        function maintains a "token stack", for when the ambiguous context
        demands that multiple tokens be parsed at once.
        """
        if self.tokenstack:
            return self.tokenstack.pop(0)

        seenletters = False
        token = None
        state = None
        wordchars = self.wordchars
        numchars = self.numchars
        whitespace = self.whitespace

        while not self.eof:
            # We only realize that we've reached the end of a token when we find
            # a character that's not part of the current token - since that
            # character may be part of the next token, it's stored in the
            # charstack.
            if self.charstack:
                nextchar = self.charstack.pop(0)
            else:
                nextchar = self.instream.read(1)
                while nextchar == '\x00':
                    nextchar = self.instream.read(1)

            if not nextchar:
                self.eof = True
                break
            elif not state:
                # First character of the token - determines if we're starting
                # to parse a word, a number or something else.
                token = nextchar
                if nextchar in wordchars:
                    state = 'a'
                elif nextchar in numchars:
                    state = '0'
                elif nextchar in whitespace:
                    token = ' '
                    break  # emit token
                else:
                    break  # emit token
            elif state == 'a':
                # If we've already started reading a word, we keep reading
                # letters until we find something that's not part of a word.
                seenletters = True
                if nextchar in wordchars:
                    token += nextchar
                elif nextchar == '.':
                    token += nextchar
                    state = 'a.'
                else:
                    self.charstack.append(nextchar)
                    break  # emit token
            elif state == '0':
                # If we've already started reading a number, we keep reading
                # numbers until we find something that doesn't fit.
                if nextchar in numchars:
                    token += nextchar
                elif nextchar == '.':
                    token += nextchar
                    state = '0.'
                else:
                    self.charstack.append(nextchar)
                    break  # emit token
            elif state == 'a.':
                # If we've seen some letters and a dot separator, continue
                # parsing, and the tokens will be broken up later.
                seenletters = True
                if nextchar == '.' or nextchar in wordchars:
                    token += nextchar
                elif nextchar in numchars and token[-1] == '.':
                    token += nextchar
                    state = '0.'
                else:
                    self.charstack.append(nextchar)
                    break  # emit token
            elif state == '0.':
                # If we've seen at least one dot separator, keep going, we'll
                # break up the tokens later.
                if nextchar == '.' or nextchar in numchars:
                    token += nextchar
                elif nextchar in wordchars and token[-1] == '.':
                    token += nextchar
                    state = 'a.'
                else:
                    self.charstack.append(nextchar)
                    break  # emit token

        if (state in ('a.', '0.') and (seenletters or token.count('.') > 1 or
                                       token[-1] == '.')):
            l = token.split('.')
            token = l[0]
            for tok in l[1:]:
                self.tokenstack.append('.')
                if tok:
                    self.tokenstack.append(tok)

        return token

    def __iter__(self):
        return self

    def __next__(self):
        token = self.get_token()
        if token is None:
            raise StopIteration

        return token

    def next(self):
        return self.__next__()  # Python 2.x support

    def split(cls, s):
        return list(cls(s))
    split = classmethod(split)


class _resultbase(object):

    def __init__(self):
        for attr in self.__slots__:
            setattr(self, attr, None)

    def _repr(self, classname):
        l = []
        for attr in self.__slots__:
            value = getattr(self, attr)
            if value is not None:
                l.append("%s=%s" % (attr, repr(value)))
        return "%s(%s)" % (classname, ", ".join(l))

    def __repr__(self):
        return self._repr(self.__class__.__name__)


class parserinfo(object):
    """
    Class which handles what inputs are accepted. Subclass this to customize the
    language and acceptable values for each parameter.

    :param dayfirst:
            Whether to interpret the first value in an ambiguous 3-integer date
            (e.g. 01/05/09) as the day (`True`) or month (`False`). If
            `yearfirst` is set to `True`, this distinguishes between YDM and
            YMD. Default is `False`.

    :param yearfirst:
            Whether to interpret the first value in an ambiguous 3-integer date
            (e.g. 01/05/09) as the year. If `True`, the first number is taken to
            be the year, otherwise the last number is taken to be the year.
            Default is `False`.
    """

    # m from a.m/p.m, t from ISO T separator
    JUMP = [" ", ".", ",", ";", "-", "/", "'",
            "at", "on", "and", "ad", "m", "t", "of",
            "st", "nd", "rd", "th"]

    WEEKDAYS = [("Mon", "Monday"),
                ("Tue", "Tuesday"),
                ("Wed", "Wednesday"),
                ("Thu", "Thursday"),
                ("Fri", "Friday"),
                ("Sat", "Saturday"),
                ("Sun", "Sunday")]
    MONTHS = [("Jan", "January"),
              ("Feb", "February"),
              ("Mar", "March"),
              ("Apr", "April"),
              ("May", "May"),
              ("Jun", "June"),
              ("Jul", "July"),
              ("Aug", "August"),
              ("Sep", "Sept", "September"),
              ("Oct", "October"),
              ("Nov", "November"),
              ("Dec", "December")]
    HMS = [("h", "hour", "hours"),
           ("m", "minute", "minutes"),
           ("s", "second", "seconds")]
    AMPM = [("am", "a"),
            ("pm", "p")]
    UTCZONE = ["UTC", "GMT", "Z"]
    PERTAIN = ["of"]
    TZOFFSET = {}

    def __init__(self, dayfirst=False, yearfirst=False):
        self._jump = self._convert(self.JUMP)
        self._weekdays = self._convert(self.WEEKDAYS)
        self._months = self._convert(self.MONTHS)
        self._hms = self._convert(self.HMS)
        self._ampm = self._convert(self.AMPM)
        self._utczone = self._convert(self.UTCZONE)
        self._pertain = self._convert(self.PERTAIN)

        self.dayfirst = dayfirst
        self.yearfirst = yearfirst

        self._year = time.localtime().tm_year
        self._century = self._year // 100*100

    def _convert(self, lst):
        dct = {}
        for i, v in enumerate(lst):
            if isinstance(v, tuple):
                for v in v:
                    dct[v.lower()] = i
            else:
                dct[v.lower()] = i
        return dct

    def jump(self, name):
        return name.lower() in self._jump

    def weekday(self, name):
        if len(name) >= 3:
            try:
                return self._weekdays[name.lower()]
            except KeyError:
                pass
        return None

    def month(self, name):
        if len(name) >= 3:
            try:
                return self._months[name.lower()]+1
            except KeyError:
                pass
        return None

    def hms(self, name):
        try:
            return self._hms[name.lower()]
        except KeyError:
            return None

    def ampm(self, name):
        try:
            return self._ampm[name.lower()]
        except KeyError:
            return None

    def pertain(self, name):
        return name.lower() in self._pertain

    def utczone(self, name):
        return name.lower() in self._utczone

    def tzoffset(self, name):
        if name in self._utczone:
            return 0

        return self.TZOFFSET.get(name)

    def convertyear(self, year):
        if year < 100:
            year += self._century
            if abs(year-self._year) >= 50:
                if year < self._year:
                    year += 100
                else:
                    year -= 100
        return year

    def validate(self, res):
        # move to info
        if res.year is not None:
            res.year = self.convertyear(res.year)

        if res.tzoffset == 0 and not res.tzname or res.tzname == 'Z':
            res.tzname = "UTC"
            res.tzoffset = 0
        elif res.tzoffset != 0 and res.tzname and self.utczone(res.tzname):
            res.tzoffset = 0
        return True


class parser(object):

    def __init__(self, info=None):
        self.info = info or parserinfo()

    def parse(self, timestr, default=None, ignoretz=False, tzinfos=None,
              **kwargs):
        """
        Parse the date/time string into a datetime object.

        :param timestr:
            Any date/time string using the supported formats.

        :param default:
            The default datetime object, if this is a datetime object and not
            `None`, elements specified in `timestr` replace elements in the
            default object.

        :param ignoretz:
            Whether or not to ignore the time zone.

        :param tzinfos:
            A time zone, to be applied to the date, if `ignoretz` is `True`.
            This can be either a subclass of `tzinfo`, a time zone string or an
            integer offset.

        :param **kwargs:
            Keyword arguments as passed to `_parse()`.

        :return:
            Returns a `datetime.datetime` object or, if the `fuzzy_with_tokens`
            option is `True`, returns a tuple, the first element being a
            `datetime.datetime` object, the second a tuple containing the
            fuzzy tokens.

        :raises ValueError:
            Raised for invalid or unknown string format, if the provided
            `tzinfo` is not in a valid format, or if an invalid date would
            be created.

        :raises OverFlowError:
            Raised if the parsed date exceeds the largest valid C integer on
            your system.
        """

        default_specified = default is not None

        if not default_specified:
            default = datetime.datetime.now().replace(hour=0, minute=0,
                                                      second=0, microsecond=0)

        if kwargs.get('fuzzy_with_tokens', False):
            res, skipped_tokens = self._parse(timestr, **kwargs)
        else:
            res = self._parse(timestr, **kwargs)

        if res is None:
            raise ValueError("Unknown string format")

        repl = {}
        for attr in ["year", "month", "day", "hour",
                     "minute", "second", "microsecond"]:
            value = getattr(res, attr)
            if value is not None:
                repl[attr] = value

        ret = default.replace(**repl)

        if res.weekday is not None and not res.day:
            ret = ret+relativedelta.relativedelta(weekday=res.weekday)

        if not ignoretz:
            if (isinstance(tzinfos, collections.Callable) or
                    tzinfos and res.tzname in tzinfos):

                if isinstance(tzinfos, collections.Callable):
                    tzdata = tzinfos(res.tzname, res.tzoffset)
                else:
                    tzdata = tzinfos.get(res.tzname)

                if isinstance(tzdata, datetime.tzinfo):
                    tzinfo = tzdata
                elif isinstance(tzdata, text_type):
                    tzinfo = tz.tzstr(tzdata)
                elif isinstance(tzdata, integer_types):
                    tzinfo = tz.tzoffset(res.tzname, tzdata)
                else:
                    raise ValueError("Offset must be tzinfo subclass, "
                                     "tz string, or int offset.")
                ret = ret.replace(tzinfo=tzinfo)
            elif res.tzname and res.tzname in time.tzname:
                ret = ret.replace(tzinfo=tz.tzlocal())
            elif res.tzoffset == 0:
                ret = ret.replace(tzinfo=tz.tzutc())
            elif res.tzoffset:
                ret = ret.replace(tzinfo=tz.tzoffset(res.tzname, res.tzoffset))

        if kwargs.get('fuzzy_with_tokens', False):
            return ret, skipped_tokens
        else:
            return ret

    class _result(_resultbase):
        __slots__ = ["year", "month", "day", "weekday",
                     "hour", "minute", "second", "microsecond",
                     "tzname", "tzoffset", "ampm"]

    def _parse(self, timestr, dayfirst=None, yearfirst=None, fuzzy=False,
               fuzzy_with_tokens=False):
        """
        Private method which performs the heavy lifting of parsing, called from
        `parse()`, which passes on its `kwargs` to this function.

        :param timestr:
            The string to parse.

        :param dayfirst:
            Whether to interpret the first value in an ambiguous 3-integer date
            (e.g. 01/05/09) as the day (`True`) or month (`False`). If
            `yearfirst` is set to `True`, this distinguishes between YDM and
            YMD. If set to `None`, this value is retrieved from the current
            `parserinfo` object (which itself defaults to `False`).

        :param yearfirst:
            Whether to interpret the first value in an ambiguous 3-integer date
            (e.g. 01/05/09) as the year. If `True`, the first number is taken to
            be the year, otherwise the last number is taken to be the year. If
            this is set to `None`, the value is retrieved from the current
            `parserinfo` object (which itself defaults to `False`).

        :param fuzzy:
            Whether to allow fuzzy parsing, allowing for string like "Today is
            January 1, 2047 at 8:21:00AM".

        :param fuzzy_with_tokens:
            If `True`, `fuzzy` is automatically set to True, and the parser will
            return a tuple where the first element is the parsed
            `datetime.datetime` datetimestamp and the second element is a tuple
            containing the portions of the string which were ignored, e.g.
            "Today is January 1, 2047 at 8:21:00AM" should return
            `(datetime.datetime(2011, 1, 1, 8, 21), (u'Today is ', u' ', u'at '))`
        """
        if fuzzy_with_tokens:
            fuzzy = True

        info = self.info

        if dayfirst is None:
            dayfirst = info.dayfirst

        if yearfirst is None:
            yearfirst = info.yearfirst

        res = self._result()
        l = _timelex.split(timestr)         # Splits the timestr into tokens

        # keep up with the last token skipped so we can recombine
        # consecutively skipped tokens (-2 for when i begins at 0).
        last_skipped_token_i = -2
        skipped_tokens = list()

        try:
            # year/month/day list
            ymd = []

            # Index of the month string in ymd
            mstridx = -1

            len_l = len(l)
            i = 0
            while i < len_l:

                # Check if it's a number
                try:
                    value_repr = l[i]
                    value = float(value_repr)
                except ValueError:
                    value = None

                if value is not None:
                    # Token is a number
                    len_li = len(l[i])
                    i += 1

                    if (len(ymd) == 3 and len_li in (2, 4)
                        and res.hour is None and (i >= len_l or (l[i] != ':' and
                                                  info.hms(l[i]) is None))):
                        # 19990101T23[59]
                        s = l[i-1]
                        res.hour = int(s[:2])

                        if len_li == 4:
                            res.minute = int(s[2:])

                    elif len_li == 6 or (len_li > 6 and l[i-1].find('.') == 6):
                        # YYMMDD or HHMMSS[.ss]
                        s = l[i-1]

                        if not ymd and l[i-1].find('.') == -1:
                            ymd.append(info.convertyear(int(s[:2])))
                            ymd.append(int(s[2:4]))
                            ymd.append(int(s[4:]))
                        else:
                            # 19990101T235959[.59]
                            res.hour = int(s[:2])
                            res.minute = int(s[2:4])
                            res.second, res.microsecond = _parsems(s[4:])

                    elif len_li == 8:
                        # YYYYMMDD
                        s = l[i-1]
                        ymd.append(int(s[:4]))
                        ymd.append(int(s[4:6]))
                        ymd.append(int(s[6:]))

                    elif len_li in (12, 14):
                        # YYYYMMDDhhmm[ss]
                        s = l[i-1]
                        ymd.append(int(s[:4]))
                        ymd.append(int(s[4:6]))
                        ymd.append(int(s[6:8]))
                        res.hour = int(s[8:10])
                        res.minute = int(s[10:12])

                        if len_li == 14:
                            res.second = int(s[12:])

                    elif ((i < len_l and info.hms(l[i]) is not None) or
                          (i+1 < len_l and l[i] == ' ' and
                           info.hms(l[i+1]) is not None)):

                        # HH[ ]h or MM[ ]m or SS[.ss][ ]s
                        if l[i] == ' ':
                            i += 1

                        idx = info.hms(l[i])

                        while True:
                            if idx == 0:
                                res.hour = int(value)

                                if value % 1:
                                    res.minute = int(60*(value % 1))

                            elif idx == 1:
                                res.minute = int(value)

                                if value % 1:
                                    res.second = int(60*(value % 1))

                            elif idx == 2:
                                res.second, res.microsecond = \
                                    _parsems(value_repr)

                            i += 1

                            if i >= len_l or idx == 2:
                                break

                            # 12h00
                            try:
                                value_repr = l[i]
                                value = float(value_repr)
                            except ValueError:
                                break
                            else:
                                i += 1
                                idx += 1

                                if i < len_l:
                                    newidx = info.hms(l[i])

                                    if newidx is not None:
                                        idx = newidx

                    elif (i == len_l and l[i-2] == ' ' and
                          info.hms(l[i-3]) is not None):
                        # X h MM or X m SS
                        idx = info.hms(l[i-3]) + 1

                        if idx == 1:
                            res.minute = int(value)

                            if value % 1:
                                res.second = int(60*(value % 1))
                            elif idx == 2:
                                res.second, res.microsecond = \
                                    _parsems(value_repr)
                                i += 1

                    elif i+1 < len_l and l[i] == ':':
                        # HH:MM[:SS[.ss]]
                        res.hour = int(value)
                        i += 1
                        value = float(l[i])
                        res.minute = int(value)

                        if value % 1:
                            res.second = int(60*(value % 1))

                        i += 1

                        if i < len_l and l[i] == ':':
                            res.second, res.microsecond = _parsems(l[i+1])
                            i += 2

                    elif i < len_l and l[i] in ('-', '/', '.'):
                        sep = l[i]
                        ymd.append(int(value))
                        i += 1

                        if i < len_l and not info.jump(l[i]):
                            try:
                                # 01-01[-01]
                                ymd.append(int(l[i]))
                            except ValueError:
                                # 01-Jan[-01]
                                value = info.month(l[i])

                                if value is not None:
                                    ymd.append(value)
                                    assert mstridx == -1
                                    mstridx = len(ymd)-1
                                else:
                                    return None

                            i += 1

                            if i < len_l and l[i] == sep:
                                # We have three members
                                i += 1
                                value = info.month(l[i])

                                if value is not None:
                                    ymd.append(value)
                                    mstridx = len(ymd)-1
                                    assert mstridx == -1
                                else:
                                    ymd.append(int(l[i]))

                                i += 1
                    elif i >= len_l or info.jump(l[i]):
                        if i+1 < len_l and info.ampm(l[i+1]) is not None:
                            # 12 am
                            res.hour = int(value)

                            if res.hour < 12 and info.ampm(l[i+1]) == 1:
                                res.hour += 12
                            elif res.hour == 12 and info.ampm(l[i+1]) == 0:
                                res.hour = 0

                            i += 1
                        else:
                            # Year, month or day
                            ymd.append(int(value))
                        i += 1
                    elif info.ampm(l[i]) is not None:

                        # 12am
                        res.hour = int(value)

                        if res.hour < 12 and info.ampm(l[i]) == 1:
                            res.hour += 12
                        elif res.hour == 12 and info.ampm(l[i]) == 0:
                            res.hour = 0
                        i += 1

                    elif not fuzzy:
                        return None
                    else:
                        i += 1
                    continue

                # Check weekday
                value = info.weekday(l[i])
                if value is not None:
                    res.weekday = value
                    i += 1
                    continue

                # Check month name
                value = info.month(l[i])
                if value is not None:
                    ymd.append(value)
                    assert mstridx == -1
                    mstridx = len(ymd)-1

                    i += 1
                    if i < len_l:
                        if l[i] in ('-', '/'):
                            # Jan-01[-99]
                            sep = l[i]
                            i += 1
                            ymd.append(int(l[i]))
                            i += 1

                            if i < len_l and l[i] == sep:
                                # Jan-01-99
                                i += 1
                                ymd.append(int(l[i]))
                                i += 1

                        elif (i+3 < len_l and l[i] == l[i+2] == ' '
                              and info.pertain(l[i+1])):
                            # Jan of 01
                            # In this case, 01 is clearly year
                            try:
                                value = int(l[i+3])
                            except ValueError:
                                # Wrong guess
                                pass
                            else:
                                # Convert it here to become unambiguous
                                ymd.append(info.convertyear(value))
                            i += 4
                    continue

                # Check am/pm
                value = info.ampm(l[i])
                if value is not None:
                    # For fuzzy parsing, 'a' or 'am' (both valid English words)
                    # may erroneously trigger the AM/PM flag. Deal with that
                    # here.
                    val_is_ampm = True

                    # If there's already an AM/PM flag, this one isn't one.
                    if fuzzy and res.ampm is not None:
                        val_is_ampm = False

                    # If AM/PM is found and hour is not, raise a ValueError
                    if res.hour is None:
                        if fuzzy:
                            val_is_ampm = False
                        else:
                            raise ValueError('No hour specified with ' +
                                             'AM or PM flag.')
                    elif not 0 <= res.hour <= 12:
                        # If AM/PM is found, it's a 12 hour clock, so raise 
                        # an error for invalid range
                        if fuzzy:
                            val_is_ampm = False
                        else:
                            raise ValueError('Invalid hour specified for ' +
                                             '12-hour clock.')

                    if val_is_ampm:
                        if value == 1 and res.hour < 12:
                            res.hour += 12
                        elif value == 0 and res.hour == 12:
                            res.hour = 0

                        res.ampm = value

                    i += 1
                    continue

                # Check for a timezone name
                if (res.hour is not None and len(l[i]) <= 5 and
                        res.tzname is None and res.tzoffset is None and
                        not [x for x in l[i] if x not in
                             string.ascii_uppercase]):
                    res.tzname = l[i]
                    res.tzoffset = info.tzoffset(res.tzname)
                    i += 1

                    # Check for something like GMT+3, or BRST+3. Notice
                    # that it doesn't mean "I am 3 hours after GMT", but
                    # "my time +3 is GMT". If found, we reverse the
                    # logic so that timezone parsing code will get it
                    # right.
                    if i < len_l and l[i] in ('+', '-'):
                        l[i] = ('+', '-')[l[i] == '+']
                        res.tzoffset = None
                        if info.utczone(res.tzname):
                            # With something like GMT+3, the timezone
                            # is *not* GMT.
                            res.tzname = None

                    continue

                # Check for a numbered timezone
                if res.hour is not None and l[i] in ('+', '-'):
                    signal = (-1, 1)[l[i] == '+']
                    i += 1
                    len_li = len(l[i])

                    if len_li == 4:
                        # -0300
                        res.tzoffset = int(l[i][:2])*3600+int(l[i][2:])*60
                    elif i+1 < len_l and l[i+1] == ':':
                        # -03:00
                        res.tzoffset = int(l[i])*3600+int(l[i+2])*60
                        i += 2
                    elif len_li <= 2:
                        # -[0]3
                        res.tzoffset = int(l[i][:2])*3600
                    else:
                        return None
                    i += 1

                    res.tzoffset *= signal

                    # Look for a timezone name between parenthesis
                    if (i+3 < len_l and
                        info.jump(l[i]) and l[i+1] == '(' and l[i+3] == ')' and
                        3 <= len(l[i+2]) <= 5 and
                        not [x for x in l[i+2]
                             if x not in string.ascii_uppercase]):
                        # -0300 (BRST)
                        res.tzname = l[i+2]
                        i += 4
                    continue

                # Check jumps
                if not (info.jump(l[i]) or fuzzy):
                    return None

                if last_skipped_token_i == i - 1:
                    # recombine the tokens
                    skipped_tokens[-1] += l[i]
                else:
                    # just append
                    skipped_tokens.append(l[i])
                last_skipped_token_i = i
                i += 1

            # Process year/month/day
            len_ymd = len(ymd)
            if len_ymd > 3:
                # More than three members!?
                return None
            elif len_ymd == 1 or (mstridx != -1 and len_ymd == 2):
                # One member, or two members with a month string
                if mstridx != -1:
                    res.month = ymd[mstridx]
                    del ymd[mstridx]

                if len_ymd > 1 or mstridx == -1:
                    if ymd[0] > 31:
                        res.year = ymd[0]
                    else:
                        res.day = ymd[0]

            elif len_ymd == 2:
                # Two members with numbers
                if ymd[0] > 31:
                    # 99-01
                    res.year, res.month = ymd
                elif ymd[1] > 31:
                    # 01-99
                    res.month, res.year = ymd
                elif dayfirst and ymd[1] <= 12:
                    # 13-01
                    res.day, res.month = ymd
                else:
                    # 01-13
                    res.month, res.day = ymd

            elif len_ymd == 3:
                # Three members
                if mstridx == 0:
                    res.month, res.day, res.year = ymd
                elif mstridx == 1:
                    if ymd[0] > 31 or (yearfirst and ymd[2] <= 31):
                        # 99-Jan-01
                        res.year, res.month, res.day = ymd
                    else:
                        # 01-Jan-01
                        # Give precendence to day-first, since
                        # two-digit years is usually hand-written.
                        res.day, res.month, res.year = ymd

                elif mstridx == 2:
                    # WTF!?
                    if ymd[1] > 31:
                        # 01-99-Jan
                        res.day, res.year, res.month = ymd
                    else:
                        # 99-01-Jan
                        res.year, res.day, res.month = ymd

                else:
                    if ymd[0] > 31 or \
                       (yearfirst and ymd[1] <= 12 and ymd[2] <= 31):
                        # 99-01-01
                        res.year, res.month, res.day = ymd
                    elif ymd[0] > 12 or (dayfirst and ymd[1] <= 12):
                        # 13-01-01
                        res.day, res.month, res.year = ymd
                    else:
                        # 01-13-01
                        res.month, res.day, res.year = ymd

        except (IndexError, ValueError, AssertionError):
            return None

        if not info.validate(res):
            return None

        if fuzzy_with_tokens:
            return res, tuple(skipped_tokens)
        else:
            return res

DEFAULTPARSER = parser()


def parse(timestr, parserinfo=None, **kwargs):
    """
    Parse a string in one of the supported formats, using the `parserinfo`
    parameters.

    :param timestr:
        A string containing a date/time stamp.

    :param parserinfo:
        A :class:`parserinfo` object containing parameters for the parser.
        If `None`, the default arguments to the `parserinfo` constructor are
        used.

    The `**kwargs` parameter takes the following keyword arguments:

    :param default:
        The default datetime object, if this is a datetime object and not
        `None`, elements specified in `timestr` replace elements in the
        default object.

    :param ignoretz:
        Whether or not to ignore the time zone (boolean).

    :param tzinfos:
        A time zone, to be applied to the date, if `ignoretz` is `True`.
        This can be either a subclass of `tzinfo`, a time zone string or an
        integer offset.

    :param dayfirst:
        Whether to interpret the first value in an ambiguous 3-integer date
        (e.g. 01/05/09) as the day (`True`) or month (`False`). If
        `yearfirst` is set to `True`, this distinguishes between YDM and
        YMD. If set to `None`, this value is retrieved from the current
        :class:`parserinfo` object (which itself defaults to `False`).

    :param yearfirst:
        Whether to interpret the first value in an ambiguous 3-integer date
        (e.g. 01/05/09) as the year. If `True`, the first number is taken to
        be the year, otherwise the last number is taken to be the year. If
        this is set to `None`, the value is retrieved from the current
        :class:`parserinfo` object (which itself defaults to `False`).

    :param fuzzy:
        Whether to allow fuzzy parsing, allowing for string like "Today is
        January 1, 2047 at 8:21:00AM".

    :param fuzzy_with_tokens:
        If `True`, `fuzzy` is automatically set to True, and the parser will
        return a tuple where the first element is the parsed
        `datetime.datetime` datetimestamp and the second element is a tuple
        containing the portions of the string which were ignored, e.g.
        "Today is January 1, 2047 at 8:21:00AM" should return
        `(datetime.datetime(2011, 1, 1, 8, 21), (u'Today is ', u' ', u'at '))`
    """
    # Python 2.x support: datetimes return their string presentation as
    # bytes in 2.x and unicode in 3.x, so it's reasonable to expect that
    # the parser will get both kinds. Internally we use unicode only.
    if isinstance(timestr, binary_type):
        timestr = timestr.decode()

    if parserinfo:
        return parser(parserinfo).parse(timestr, **kwargs)
    else:
        return DEFAULTPARSER.parse(timestr, **kwargs)


class _tzparser(object):

    class _result(_resultbase):

        __slots__ = ["stdabbr", "stdoffset", "dstabbr", "dstoffset",
                     "start", "end"]

        class _attr(_resultbase):
            __slots__ = ["month", "week", "weekday",
                         "yday", "jyday", "day", "time"]

        def __repr__(self):
            return self._repr("")

        def __init__(self):
            _resultbase.__init__(self)
            self.start = self._attr()
            self.end = self._attr()

    def parse(self, tzstr):
        # Python 2.x compatibility: tzstr should be converted to unicode before
        # being passed to _timelex.
        if isinstance(tzstr, binary_type):
            tzstr = tzstr.decode()

        res = self._result()
        l = _timelex.split(tzstr)
        try:

            len_l = len(l)

            i = 0
            while i < len_l:
                # BRST+3[BRDT[+2]]
                j = i
                while j < len_l and not [x for x in l[j]
                                         if x in "0123456789:,-+"]:
                    j += 1
                if j != i:
                    if not res.stdabbr:
                        offattr = "stdoffset"
                        res.stdabbr = "".join(l[i:j])
                    else:
                        offattr = "dstoffset"
                        res.dstabbr = "".join(l[i:j])
                    i = j
                    if (i < len_l and (l[i] in ('+', '-') or l[i][0] in
                                       "0123456789")):
                        if l[i] in ('+', '-'):
                            # Yes, that's right.  See the TZ variable
                            # documentation.
                            signal = (1, -1)[l[i] == '+']
                            i += 1
                        else:
                            signal = -1
                        len_li = len(l[i])
                        if len_li == 4:
                            # -0300
                            setattr(res, offattr, (int(l[i][:2])*3600 +
                                                   int(l[i][2:])*60)*signal)
                        elif i+1 < len_l and l[i+1] == ':':
                            # -03:00
                            setattr(res, offattr,
                                    (int(l[i])*3600+int(l[i+2])*60)*signal)
                            i += 2
                        elif len_li <= 2:
                            # -[0]3
                            setattr(res, offattr,
                                    int(l[i][:2])*3600*signal)
                        else:
                            return None
                        i += 1
                    if res.dstabbr:
                        break
                else:
                    break

            if i < len_l:
                for j in range(i, len_l):
                    if l[j] == ';':
                        l[j] = ','

                assert l[i] == ','

                i += 1

            if i >= len_l:
                pass
            elif (8 <= l.count(',') <= 9 and
                  not [y for x in l[i:] if x != ','
                       for y in x if y not in "0123456789"]):
                # GMT0BST,3,0,30,3600,10,0,26,7200[,3600]
                for x in (res.start, res.end):
                    x.month = int(l[i])
                    i += 2
                    if l[i] == '-':
                        value = int(l[i+1])*-1
                        i += 1
                    else:
                        value = int(l[i])
                    i += 2
                    if value:
                        x.week = value
                        x.weekday = (int(l[i])-1) % 7
                    else:
                        x.day = int(l[i])
                    i += 2
                    x.time = int(l[i])
                    i += 2
                if i < len_l:
                    if l[i] in ('-', '+'):
                        signal = (-1, 1)[l[i] == "+"]
                        i += 1
                    else:
                        signal = 1
                    res.dstoffset = (res.stdoffset+int(l[i]))*signal
            elif (l.count(',') == 2 and l[i:].count('/') <= 2 and
                  not [y for x in l[i:] if x not in (',', '/', 'J', 'M',
                                                     '.', '-', ':')
                       for y in x if y not in "0123456789"]):
                for x in (res.start, res.end):
                    if l[i] == 'J':
                        # non-leap year day (1 based)
                        i += 1
                        x.jyday = int(l[i])
                    elif l[i] == 'M':
                        # month[-.]week[-.]weekday
                        i += 1
                        x.month = int(l[i])
                        i += 1
                        assert l[i] in ('-', '.')
                        i += 1
                        x.week = int(l[i])
                        if x.week == 5:
                            x.week = -1
                        i += 1
                        assert l[i] in ('-', '.')
                        i += 1
                        x.weekday = (int(l[i])-1) % 7
                    else:
                        # year day (zero based)
                        x.yday = int(l[i])+1

                    i += 1

                    if i < len_l and l[i] == '/':
                        i += 1
                        # start time
                        len_li = len(l[i])
                        if len_li == 4:
                            # -0300
                            x.time = (int(l[i][:2])*3600+int(l[i][2:])*60)
                        elif i+1 < len_l and l[i+1] == ':':
                            # -03:00
                            x.time = int(l[i])*3600+int(l[i+2])*60
                            i += 2
                            if i+1 < len_l and l[i+1] == ':':
                                i += 2
                                x.time += int(l[i])
                        elif len_li <= 2:
                            # -[0]3
                            x.time = (int(l[i][:2])*3600)
                        else:
                            return None
                        i += 1

                    assert i == len_l or l[i] == ','

                    i += 1

                assert i >= len_l

        except (IndexError, ValueError, AssertionError):
            return None

        return res


DEFAULTTZPARSER = _tzparser()


def _parsetz(tzstr):
    return DEFAULTTZPARSER.parse(tzstr)


def _parsems(value):
    """Parse a I[.F] seconds value into (seconds, microseconds)."""
    if "." not in value:
        return int(value), 0
    else:
        i, f = value.split(".")
        return int(i), int(f.ljust(6, "0")[:6])


# vim:ts=4:sw=4:et
