src/_hkml_date.py

# SPDX-License-Identifier: GPL-2.0

import datetime
import subprocess

def parse_date_diff(date_str, now):
    # format: {-,+}[0-9]+ {days,hours,minutes}
    # e.g., -2 days, +3 days, +1 hours
    fields = date_str.split()
    if len(fields) != 2:
        return None
    nr, unit = fields
    try:
        nr = int(nr)
    except:
        return None
    if not unit in ['days', 'hours', 'minutes']:
        return None
    if unit == 'days':
        timedelta = datetime.timedelta(days=nr)
    elif unit == 'hours':
        timedelta = datetime.timedelta(hours=nr)
    elif unit == 'minutes':
        timedelta = datetime.timedelta(minutes=nr)
    return now + timedelta

def parse_date(date_str):
    now = datetime.datetime.now().astimezone()
    the_date = parse_date_diff(date_str, now)
    if the_date is not None:
        return the_date, None
    for s in ['-', ':', '/']:
        date_str = date_str.replace(s, ' ')
    fields = date_str.split()
    if not len(fields) in [5, 3, 2, 1]:
        return None, 'unexpected number of fields (%d)' % len(fields)
    if fields[0] == 'yesterday':
        yesterday = now - datetime.timedelta(1)
        fields = [yesterday.year, yesterday.month, yesterday.day] + fields[1:]
    try:
        numbers = [int(x) for x in fields]
    except ValueError as e:
        return None, '%s' % e
    if not len(numbers) in [5, 3, 2]:
        # 5: year month day hour minute
        # 3: year month day
        # 2: hour minute
        return None, 'only 5, 3, or 2 numbers are supported date input'
    if len(numbers) == 2:
        numbers = [now.year, now.month, now.day] + numbers
    try:
        return datetime.datetime(*numbers).astimezone(), None
    except Exception as e:
        return None, '%s' % e

def parse_iso_date(date):
    try:
        return datetime.datetime.fromisoformat(date).astimezone()
    except:
        # maybe lower version of python.
        # the input 'date' may have UTC offset with hour separator, like
        # '+05:00', while strptime() '%z' expoects no such separator.  Make
        # it compatible.
        date = '%s%s' % (date[:-3], date[-2:])
        return datetime.datetime.strptime(
                date, '%Y-%m-%dT%H:%M:%S%z').astimezone()

def commit_date(commit):
    try:
        text = subprocess.check_output(
                ['git', 'log', '-1', commit, '--pretty=%cd',
                 '--date=iso-strict'],
                stderr=subprocess.DEVNULL).decode().strip()
    except Exception as e:
        return None, 'git log %s fail (%s)' % (commit, e)
    try:
        return parse_iso_date(text), None
    except Exception as e:
        return None, 'parsing date (%s) fail (%s)' % (text, e)

def parse_date_arg_non_commit(tokens):
    try:
        date_str = ' '.join(tokens)
    except Exception as e:
        return None, 'tokens to string conversion fail (%s)' % e
    return parse_date(date_str)

def parse_date_arg(tokens):
    parsed, err = parse_date_arg_non_commit(tokens)
    if err is None:
        return parsed, err
    if len(tokens) != 1:
        return parsed, err
    parsed, err2 = commit_date(tokens[0])
    if err2 != None:
        err = 'parsing date argument fail (%s, %s)' % (err2, err)
    else:
        err = None
    return parsed, err

def date_format_description():
    return ' '.join([
        'For date argument, following formats are supported/.',
        'Relative date ({-,+}[0-9]+ {days,hours,minutes}), e.g., -3 days.',
        'Explicit date ("YYYY MM DD", "YYYY MM DD HH MM", or "HH MM").',
        '"-", "/", ":" on explicit daste input are treated as space.',
        '\'yesterday\'.',
        'Commit (the commit date), e.g., v6.14).'
        ])

def add_date_arg(parser, option_name, help_msg):
    format_msg = date_format_description()
    if parser.epilog is None:
        parser.epilog = format_msg
    elif parser.epilog.find(format_msg) == -1:
        parser.epilog += format_msg
    help_msg += ' Format: show end of this message.'
    parser.add_argument(
            option_name, metavar='<date token>', nargs='+',
            help=help_msg)