import re
from datetime import datetime

from dateutil.relativedelta import relativedelta

DEFAULT_TIME_FORMAT = "%Y-%m-%d %H:%M:%S"

regex = re.compile(
    r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?"
    r"((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?"
)


# parse_time parses timedelta string to time dict
# input: <string> 1y2m3w5d - all values should be integer
# output: <dict> {year: 1, month: 2, week: 3, day: 5}
def parse_timedelta_string(time_str):
    empty_flag = True
    try:
        parts = regex.match(time_str)
        if not parts:
            return None
        parts = parts.groupdict()
        time_params = {}
        for key in parts:
            if parts[key]:
                time_params[key] = int(parts[key])
                empty_flag = False
            else:
                time_params[key] = 0
        if empty_flag:
            return None
        return time_params
    except: # noqa: E722
        return None


def get_current_time():
    return datetime.now()


def get_current_strtime():
    now = datetime.now()
    return now.strftime(DEFAULT_TIME_FORMAT)


def timeago(
    years=0, months=0, weeks=0, days=0, hours=0, minutes=0, seconds=0, from_date=None
):
    if from_date is None:
        from_date = datetime.now()
    return from_date - relativedelta(
        years=years,
        months=months,
        weeks=weeks,
        days=days,
        hours=hours,
        minutes=minutes,
        seconds=seconds,
    )