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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
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# software distributed under the License is distributed on an
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from __future__ import annotations

import datetime
import sys
from typing import TYPE_CHECKING, Any, cast

from airflow.utils.module_loading import qualname

if TYPE_CHECKING:
    from airflow.serialization.serde import U


serializers = [
    "pendulum.tz.timezone.FixedTimezone",
    "pendulum.tz.timezone.Timezone",
]

PY39 = sys.version_info >= (3, 9)

if PY39:
    serializers.append("zoneinfo.ZoneInfo")
else:
    serializers.append("backports.zoneinfo.ZoneInfo")

deserializers = serializers

__version__ = 1


def serialize(o: object) -> tuple[U, str, int, bool]:
    """
    Encode a Pendulum Timezone for serialization.

    Airflow only supports timezone objects that implements Pendulum's Timezone
    interface. We try to keep as much information as possible to make conversion
    round-tripping possible (see ``decode_timezone``). We need to special-case
    UTC; Pendulum implements it as a FixedTimezone (i.e. it gets encoded as
    0 without the special case), but passing 0 into ``pendulum.timezone`` does
    not give us UTC (but ``+00:00``).
    """
    from pendulum.tz.timezone import FixedTimezone

    name = qualname(o)

    if isinstance(o, FixedTimezone):
        if o.offset == 0:
            return "UTC", name, __version__, True
        return o.offset, name, __version__, True

    tz_name = _get_tzinfo_name(cast(datetime.tzinfo, o))
    if tz_name is not None:
        return tz_name, name, __version__, True

    if cast(datetime.tzinfo, o).utcoffset(None) == datetime.timedelta(0):
        return "UTC", qualname(FixedTimezone), __version__, True

    return "", "", 0, False


def deserialize(classname: str, version: int, data: object) -> Any:
    from airflow.utils.timezone import parse_timezone

    if not isinstance(data, (str, int)):
        raise TypeError(f"{data} is not of type int or str but of {type(data)}")

    if version > __version__:
        raise TypeError(f"serialized {version} of {classname} > {__version__}")

    if "zoneinfo.ZoneInfo" in classname:
        try:
            from zoneinfo import ZoneInfo
        except ImportError:
            from backports.zoneinfo import ZoneInfo  # type: ignore[no-redef]

        return ZoneInfo(data)  # type: ignore[arg-type]

    return parse_timezone(data)


# ported from pendulum.tz.timezone._get_tzinfo_name
def _get_tzinfo_name(tzinfo: datetime.tzinfo | None) -> str | None:
    if tzinfo is None:
        return None

    if hasattr(tzinfo, "key"):
        # zoneinfo timezone
        return tzinfo.key
    elif hasattr(tzinfo, "name"):
        # Pendulum timezone
        return tzinfo.name
    elif hasattr(tzinfo, "zone"):
        # pytz timezone
        return tzinfo.zone  # type: ignore[no-any-return]

    return None