import sys
from datetime import datetime

from sqlalchemy import String, Text, ForeignKey, event, DateTime, select
from sqlalchemy.ext.compiler import compiles
from sqlalchemy.orm import Mapped, mapped_column, declared_attr, relationship, Session
from sqlalchemy.sql import expression

from .base import Base
from .status import StatusForeignKey

__all__ = ['User', 'Versioned']


# noinspection PyPep8Naming
class utcnow(expression.FunctionElement):
    type = DateTime()
    inherit_cache = True


# noinspection PyUnusedLocal
@compiles(utcnow, "postgresql")
def pg_utcnow(*args, **kwargs):
    return "TIMEZONE('utc', CURRENT_TIMESTAMP)"


# noinspection PyUnusedLocal
@compiles(utcnow, "mssql")
def ms_utcnow(*args, **kwargs):
    return "GETUTCDATE()"


# noinspection PyUnusedLocal
@compiles(utcnow, "mysql")
def my_utcnow(*args, **kwargs):
    return "UTC_TIMESTAMP(6)"


# noinspection PyUnusedLocal
@compiles(utcnow, "mariadb")
def maria_utcnow(*args, **kwargs):
    return "UTC_TIMESTAMP(6)"


# noinspection PyUnusedLocal
@compiles(utcnow, "sqlite")
def sqlite_utcnow(*args, **kwargs):
    return "strftime('%Y-%m-%d %H:%M:%S')"


class Versioned:

    # noinspection PyMethodParameters
    @declared_attr
    def __versioned__(cls):
        return {}

    _created__: Mapped[datetime] = mapped_column(server_default=utcnow(), sort_order=sys.maxsize, default=None)
    _updated__: Mapped[datetime | None] = mapped_column(onupdate=utcnow(), sort_order=sys.maxsize)
    _user__id: Mapped[int | None] = mapped_column(ForeignKey("user.id"), sort_order=sys.maxsize)

    # noinspection PyMethodParameters
    @declared_attr
    def _user__(cls) -> Mapped["User"]:
        return relationship()


class User(StatusForeignKey, Versioned, Base):
    """User"""

    username: Mapped[str] = mapped_column(String(253), unique=True)
    name: Mapped[str] = mapped_column(String(253))
    password: Mapped[str | None] = mapped_column(String(255))
    ldap_name: Mapped[str | None] = mapped_column(String(255))
    notes: Mapped[str | None] = mapped_column(Text)

    def __repr__(self):
        return f'User(id={self.id!r}, username={self.username!r} name={self.name!r}, notes={self.notes!r})'

# noinspection PyUnusedLocal
@event.listens_for(User.__table__, "after_create")
def initialize_user(target, connection, **kwargs):
    from routers.user import get_password_hash
    with Session(connection) as session:
        qsys = User(username="QSYS", name="System User", notes="internal processing", status_id='X')
        session.add(qsys)
        session.commit()
        qsys = session.scalar(select(User).where(User.username == "QSYS"))
        qsys._user__id=qsys.id
        session.commit()
        for kwargs in (
                dict(username="CTM", name="Control-M", password=get_password_hash("secret"), notes="user for automation"),
                dict(username="exde37c8", name="Bernhard Radermacher",
                     password=get_password_hash("secret"),
                     ldap_name="a0061806@kiongroup.com",
                     ),
        ):
            kwargs.update(dict(status_id='A', _user__id=qsys.id))
            session.add(User(**kwargs))
        session.commit()