pytimeparse2.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
(c) Sergey Klyuykov <onegreyonewhite@mail.ru> 3 Nov 2021

Implements a single function, `timeparse`, which can parse various
kinds of time expressions.
"""

# MIT LICENSE
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

__version__ = '1.3.1'

import typing
import re

SIGN = r'(?P<sign>[+|-]|\+)?'
WEEKS = r'(?P<weeks>[\d.]+)\s*(?:w|wks?|weeks?)'
DAYS = r'(?P<days>[\d.]+)\s*(?:d|dys?|days?)'
HOURS = r'(?P<hours>[\d.]+)\s*(?:h|hrs?|hours?)'
MINS = r'(?P<mins>[\d.]+)\s*(?:m|(mins?)|(minutes?))'
SECS = r'(?P<secs>[\d.]+)\s*(?:s|secs?|seconds?)'
MILLIS = r'(?P<millis>[\d.]+)\s*(?:ms|msecs?|millis|milliseconds?)'
SEPARATORS = r'[,/]'
SECCLOCK = r':(?P<secs>\d{2}(?:\.\d+)?)'
MINCLOCK = r'(?P<mins>\d{1,2}):(?P<secs>\d{2}(?:\.\d+)?)'
HOURCLOCK = r'(?P<hours>\d+):(?P<mins>\d{2}):(?P<secs>\d{2}(?:\.\d+)?)'
DAYCLOCK = (r'(?P<days>\d+):(?P<hours>\d{2}):'
            r'(?P<mins>\d{2}):(?P<secs>\d{2}(?:\.\d+)?)')

MULTIPLIERS = {
    'weeks': 60 * 60 * 24 * 7,
    'days': 60 * 60 * 24,
    'hours': 60 * 60,
    'mins': 60,
    'secs': 1,
    'millis': 1e-3,
}


def OPT(x):
    return r'(?:{x})?'.format(x=x)


def OPTSEP(x):
    return r'(?:{x}\s*(?:{SEPARATORS}\s*)?)?'.format(x=x, SEPARATORS=SEPARATORS)


TIMEFORMATS = [
    rf'{OPTSEP(WEEKS)}\s*{OPTSEP(DAYS)}\s*{OPTSEP(HOURS)}\s*{OPTSEP(MINS)}\s*{OPT(SECS)}\s*{OPT(MILLIS)}',
    rf'{MINCLOCK}',
    rf'{OPTSEP(WEEKS)}\s*{OPTSEP(DAYS)}\s*{HOURCLOCK}',
    rf'{DAYCLOCK}',
    rf'{SECCLOCK}',
]

COMPILED_SIGN = re.compile(r'\s*' + SIGN + r'\s*(?P<unsigned>.*)$')
COMPILED_TIMEFORMATS = [
    re.compile(r'\s*' + timefmt + r'\s*$', re.I)
    for timefmt in TIMEFORMATS
]


def _interpret_as_minutes(sval, mdict):
    """
    Times like "1:22" are ambiguous; do they represent minutes and seconds
    or hours and minutes?  By default, parse assumes the latter.  Call
    this function after parsing out a dictionary to change that assumption.

    >>> import pprint
    >>> pprint.pprint(_interpret_as_minutes('1:24', {'secs': '24', 'mins': '1'}))
    {'hours': '1', 'mins': '24'}
    """
    if sval.count(':') == 1 and '.' not in sval and (('hours' not in mdict) or (mdict['hours'] is None)) and (
            ('days' not in mdict) or (mdict['days'] is None)) and (('weeks' not in mdict) or (mdict['weeks'] is None)):
        mdict['hours'] = mdict['mins']
        mdict['mins'] = mdict['secs']
        mdict.pop('secs')
    return mdict


def _parse(
        sval: typing.Union[str, int, float],
        granularity: str = 'seconds'
) -> typing.Optional[typing.Union[int, float]]:
    """
    Parse a time expression, returning it as a number of seconds.  If
    possible, the return value will be an `int`; if this is not
    possible, the return will be a `float`.  Returns `None` if a time
    expression cannot be parsed from the given string.

    Arguments:
    - `sval`: the string value to parse

    >>> parse('1:24')
    84
    >>> parse(':22')
    22
    >>> parse('1 minute, 24 secs')
    84
    >>> parse('1m24s')
    84
    >>> parse('1.2 minutes')
    72
    >>> parse('1.2 seconds')
    1.2

    Time expressions can be signed.

    >>> parse('- 1 minute')
    -60
    >>> parse('+ 1 minute')
    60

    If granularity is specified as ``minutes``, then ambiguous digits following
    a colon will be interpreted as minutes; otherwise they are considered seconds.

    >>> parse('1:30')
    90
    >>> parse('1:30', granularity='minutes')
    5400
    """
    if isinstance(sval, (int, float)):
        return int(sval)

    match = COMPILED_SIGN.match(sval)
    sign = -1 if match.groupdict()['sign'] == '-' else 1  # type: ignore
    sval = match.groupdict()['unsigned']  # type: ignore

    for timefmt in COMPILED_TIMEFORMATS:
        match = timefmt.match(sval)

        if not (match and match.group(0).strip()):
            continue

        mdict = match.groupdict()
        if granularity == 'minutes':
            mdict = _interpret_as_minutes(sval, mdict)

        # if all of the fields are numbers
        if all(v.isdigit() for v in mdict.values() if v):
            return sign * sum([
                MULTIPLIERS[k] * int(v, 10)  # type: ignore
                for k, v in mdict.items()
                if v is not None
            ])
        # if SECS is an integer number
        elif 'secs' not in mdict or mdict['secs'] is None or mdict['secs'].isdigit():
            # we will return an integer
            return (int(mdict['secs'], 10) if mdict['secs'] else 0) + sign * int(sum([
                MULTIPLIERS[k] * float(v)
                for k, v in mdict.items()
                if k != 'secs' and v is not None
            ]))
        else:
            # SECS is a float, we will return a float
            return sign * sum([
                MULTIPLIERS[k] * float(v)  # type: ignore
                for k, v in mdict.items()
                if v is not None
            ])

    return int(float(sval)) * sign


def parse(
        sval: typing.Union[str, int, float],
        granularity: str = 'seconds'
) -> typing.Optional[typing.Union[int, float]]:
    try:
        return _parse(sval, granularity)
    except Exception:
        return None