import calendar
import datetime
from email.utils import formatdate

import pytest

from webob import datetime_utils


def test_UTC():
    """Test missing function in _UTC"""
    x = datetime_utils.UTC
    assert x.tzname(datetime.datetime.now()) == "UTC"
    assert x.dst(datetime.datetime.now()) == datetime.timedelta(0)
    assert x.utcoffset(datetime.datetime.now()) == datetime.timedelta(0)
    assert repr(x) == "UTC"


# Testing datetime_utils.parse_date.
# We need to verify the following scenarios:
#     * a nil submitted value
#     * a submitted value that cannot be parse into a date
#     * a valid RFC2822 date with and without timezone


class Uncooperative:
    def __str__(self):
        raise NotImplementedError


@pytest.mark.parametrize("invalid_date", [None, "Hi there", 1, "\xc3", Uncooperative()])
def test_parse_date_invalid(invalid_date):
    assert datetime_utils.parse_date(invalid_date) is None


@pytest.mark.parametrize(
    "valid_date, parsed_datetime",
    [
        (
            "Mon, 20 Nov 1995 19:12:08 -0500",
            datetime.datetime(1995, 11, 21, 0, 12, 8, tzinfo=datetime_utils.UTC),
        ),
        (
            "Mon, 20 Nov 1995 19:12:08",
            datetime.datetime(1995, 11, 20, 19, 12, 8, tzinfo=datetime_utils.UTC),
        ),
    ],
)
def test_parse_date_valid(valid_date, parsed_datetime):
    assert datetime_utils.parse_date(valid_date) == parsed_datetime


def test_serialize_date():
    """Testing datetime_utils.serialize_date
    We need to verify the following scenarios:
        * on py3, passing an binary date, return the same date but str
        * on py2, passing an unicode date, return the same date but str
        * passing a timedelta, return now plus the delta
        * passing an invalid object, should raise ValueError
    """
    from webob.util import text_

    ret = datetime_utils.serialize_date("Mon, 20 Nov 1995 19:12:08 GMT")
    assert isinstance(ret, str)
    assert ret == "Mon, 20 Nov 1995 19:12:08 GMT"
    ret = datetime_utils.serialize_date(text_("Mon, 20 Nov 1995 19:12:08 GMT"))
    assert isinstance(ret, str)
    assert ret == "Mon, 20 Nov 1995 19:12:08 GMT"
    dt = formatdate(
        calendar.timegm((datetime.datetime.now() + datetime.timedelta(1)).timetuple()),
        usegmt=True,
    )
    assert dt == datetime_utils.serialize_date(datetime.timedelta(1))
    with pytest.raises(ValueError):
        datetime_utils.serialize_date(None)


def test_parse_date_delta():
    """Testing datetime_utils.parse_date_delta
    We need to verify the following scenarios:
        * passing a nil value, should return nil
        * passing a value that fails the conversion to int, should call
          parse_date
    """
    assert datetime_utils.parse_date_delta(None) is None, (
        "Passing none value," "should return None"
    )
    ret = datetime_utils.parse_date_delta("Mon, 20 Nov 1995 19:12:08 -0500")
    assert ret == datetime.datetime(1995, 11, 21, 0, 12, 8, tzinfo=datetime_utils.UTC)
    WHEN = datetime.datetime(2011, 3, 16, 10, 10, 37, tzinfo=datetime_utils.UTC)
    with _NowRestorer(WHEN):
        ret = datetime_utils.parse_date_delta(1)
        assert ret == WHEN + datetime.timedelta(0, 1)


def test_serialize_date_delta():
    """Testing datetime_utils.serialize_date_delta
    We need to verify the following scenarios:
        * if we pass something that's not an int or float, it should delegate
          the task to serialize_date
    """
    assert datetime_utils.serialize_date_delta(1) == "1"
    assert datetime_utils.serialize_date_delta(1.5) == "1"
    ret = datetime_utils.serialize_date_delta("Mon, 20 Nov 1995 19:12:08 GMT")
    assert type(ret) is (str)
    assert ret == "Mon, 20 Nov 1995 19:12:08 GMT"


def test_timedelta_to_seconds():
    val = datetime.timedelta(86400)
    result = datetime_utils.timedelta_to_seconds(val)
    assert result == 7464960000


class _NowRestorer:
    def __init__(self, new_now):
        self._new_now = new_now
        self._old_now = None

    def __enter__(self):
        import webob.datetime_utils

        self._old_now = webob.datetime_utils._now
        webob.datetime_utils._now = lambda: self._new_now

    def __exit__(self, exc_type, exc_value, traceback):
        import webob.datetime_utils

        webob.datetime_utils._now = self._old_now