"""Base model and mixins for SQLAlchemy ORM."""

import uuid
from datetime import datetime, timezone

from sqlalchemy import DateTime
from sqlalchemy.ext.asyncio import AsyncAttrs
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


def utc_now() -> datetime:
    """Return current UTC datetime."""
    return datetime.now(timezone.utc)


class Base(AsyncAttrs, DeclarativeBase):
    """Base class for all SQLAlchemy models."""

    pass


class UUIDMixin:
    """Mixin that adds a UUID primary key."""

    id: Mapped[uuid.UUID] = mapped_column(
        primary_key=True,
        default=uuid.uuid4,
    )


class TimestampMixin:
    """Mixin that adds created_at and updated_at timestamps."""

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=utc_now,
        nullable=False,
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=utc_now,
        onupdate=utc_now,
        nullable=False,
    )