import datetime

from sqlalchemy import DateTime
from sqlalchemy import TypeDecorator


class TZDateTime(TypeDecorator):
    impl = DateTime
    cache_ok = True

    def process_bind_param(self, value, dialect):
        if value is not None:
            value = value.astimezone(datetime.timezone.utc).replace(tzinfo=None)
        return value

    def process_result_value(self, value, dialect):
        if value is not None:
            value = value.replace(tzinfo=datetime.timezone.utc)
        return value