#! /usr/bin/env python3
"""
This module isolates all date parsing in one place

str_to_date() is the only entry point
"""
import re
import os
import logging
import datetime

from typing import Optional

from .exceptions import UnknownDateFormat


log = logging.getLogger(__name__)
logging.basicConfig(level=os.environ.get("LOGLEVEL", "INFO"))

# http://docs.python.org/library/datetime.html#strftime-strptime-behavior
_DATE_FORMATS = [
    "%d-%b-%Y",  # 02-jan-2000
    "%d-%m-%Y",  # 02-01-2000
    "%d.%m.%Y",  # 02.02.2000
    "%d/%m/%Y",  # 01/06/2011
    "%Y-%m-%d",  # 2000-01-02
    "%Y.%m.%d",  # 2000.01.02
    "%Y/%m/%d",  # 2005/05/30
    "%b-%Y",  # aug-1996
    "before %b-%Y",  # before aug-1996
    "before %Y%m%d",  # before 19950101
    "%Y.%m.%d %H:%M:%S",  # 2002.09.19 13:00:00
    "%Y%m%d %H:%M:%S",  # 20110908 14:44:51
    "%Y-%m-%d %H:%M:%S",  # 2011-09-08 14:44:51
    "%Y-%m-%d %H:%M:%S%z",  # 2025-04-27 02:54:19+03:00
    "%Y-%m-%d %H:%M:%S %z",  # 2020-05-18 01:30:25 +0200
    "%Y-%m-%d %H:%M:%S CLST",  # 2011-09-08 14:44:51 CLST CL
    "%Y-%m-%d %H:%M:%S.%f",  # 2011-09-08 14:44:51 CLST CL
    "%d.%m.%Y  %H:%M:%S",  # 19.09.2002 13:00:00
    "%d-%b-%Y %H:%M:%S %Z",  # 24-Jul-2009 13:20:03 UTC
    "%Y/%m/%d %H:%M:%S (%z)",  # 2011/06/01 01:05:01 (+0900)
    "%Y/%m/%d %H:%M:%S",  # 2011/06/01 01:05:01
    "%a %b %d %H:%M:%S %Z %Y",  # Tue Jun 21 23:59:59 GMT 2011
    "%a %b %d %Y",  # Tue Dec 12 2000
    "%Y-%m-%dT%H:%M:%S",  # 2007-01-26T19:10:31
    "%Y-%m-%dT%H:%M:%SZ",  # 2007-01-26T19:10:31Z
    "%Y-%m-%dt%H:%M:%S.%fz",  # 2007-01-26t19:10:31.00z
    "%Y-%m-%dT%H:%M:%S%z",  # 2011-03-30T19:36:27+0200
    "%Y-%m-%dT%H:%M:%S.%f%z",  # 2011-09-08T14:44:51.622265+03:00
    "%Y-%m-%dt%H:%M:%S.%f",  # 2011-09-08t14:44:51.622265
    "%Y-%m-%dt%H:%M:%S",  # 2007-01-26T19:10:31
    "%Y-%m-%dt%H:%M:%SZ",  # 2007-01-26T19:10:31Z
    "%Y-%m-%dt%H:%M:%Sz",  # 2007-01-26T19:10:31Z
    "%Y-%m-%dt%H:%M:%S.%fz",  # 2007-01-26t19:10:31.00z
    "%Y-%m-%dt%H:%M:%S%z",  # 2011-03-30T19:36:27+0200
    "%Y-%m-%dt%H:%M:%S.%f%z",  # 2011-09-08T14:44:51.622265+03:00
    "%Y%m%d",  # 20110908
    "%Y. %m. %d.",  # 2020. 01. 12.
    "before %b-%Y",  # before aug-1996
    "%a %d %b %Y",  # Tue 21 Jun 2011
    "%A %d %b %Y",  # Tuesday 21 Jun 2011
    "%a %d %B %Y",  # Tue 21 June 2011
    "%A %d %B %Y",  # Tuesday 21 June 2011
    "%Y-%m-%d %H:%M:%S (%Z+0:00)",  # 2007-12-24 10:24:32 (gmt+0:00)
    "%d-%m-%Y %H:%M:%S %Z+1",  # 19-04-2021 13:56:51 GMT+1
    "%B %d %Y",  # January 01 2000
    "%Y-%b-%d",  # 2021-Oct-18
    "%d/%m/%Y %H:%M:%S",  # 08/09/2011 14:44:51
    "%m/%d/%Y",  # 03/28/2013
    "%d %b %Y",  # 28 jan 2021
    "%d-%b-%Y %H:%M:%S",  # 30-nov-2009 17:00:58
    "%Y%m%d%H%M%S",  # 20071224102432 used in edu_ua
    "%Y-%m-%d %H:%M:%S (%Z%z)",  # .tw uses (UTC+8) but we need (UTC+0800) for %z match
    "%d %B %Y at %H:%M:%S.%f",  # 07 january 2020 at 23:38:30.772
    "%Y-%m-%d %H:%M:%S.%f %Z",  # 2022-09-18 22:38:18.0 UTC (sn Senegal),
    "%a %b %d %H:%M:%S %Y",  # Thu Oct 21 05:54:20 2032 (kg Kyrgyzstan)
    "%m-%d-%Y",  # 03-28-2013 # is ambivalent for all days <=12
]

_CUSTOM_DATE_FORMATS = {
    "ml": "%m/%d/%Y",
}


def str_to_date(
    text: str,
    tld: Optional[str] = None,
    verbose: bool = False,
) -> Optional[datetime.datetime]:
    text = text.strip().lower()

    noDate = [
        "not defined",
        "n/a",
        "none",
    ]
    if not text or text in noDate:
        return None

    # replace japan standard time to +0900 (%z format)
    text = text.replace("(jst)", "(+0900)")
    text = re.sub(r"(\+[0-9]{2}):([0-9]{2})", "\\1\\2", text)

    # text = re.sub(r"(\+[0-9]{2})$", "\\1:00", text)
    # text = re.sub(r"(\+[0-9]{2})$", "\\100", text) # python 3.6 does not parse : in the timezone offset
    if re.search(r"(\+[0-9]{2})$", text):
        text = text + "00"

    # strip trailing space and comment
    text = re.sub(r"(\ #.*)", "", text)

    # tw uses UTC+8, but strptime needs UTC+0800), note we are now lower case
    r = r"\(utc([-+])(\d)\)"
    if re.search(r, text):
        text = re.sub(r, "(utc\\g<1>0\\g<2>00)", text)

    # hack for 1st 2nd 3rd 4th etc
    # better here https://stackoverflow.com/questions/1258199/python-datetime-strptime-wildcard
    text = re.sub(r"(\d+)(st|nd|rd|th) ", r"\1 ", text)

    # Remove consecutive whitespace
    text = re.sub(r"\s\s+", r" ", text)

    # 07 january 2020 at 23:38:30.772
    # %d %B %Y at %H:%M %S.%f
    if tld and tld in _CUSTOM_DATE_FORMATS:
        return (
            datetime.datetime.strptime(
                text,
                _CUSTOM_DATE_FORMATS[tld],
            )
            .astimezone()
            .replace(tzinfo=None)
        )

    for f in _DATE_FORMATS:
        try:
            z = datetime.datetime.strptime(text, f)
            z = z.astimezone()
            z = z.replace(tzinfo=None)
            return z
        except ValueError as v:
            _ = v

    raise UnknownDateFormat(f"Unknown date format: '{text}'")


if __name__ == "__main__":
    pass