"""Author RAG Chatbot SaaS — SQLAlchemy Base Model and Mixins."""

import uuid
from datetime import datetime, timezone

from sqlalchemy import DateTime, String
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


class Base(DeclarativeBase):
    """Base class for all SQLAlchemy ORM models."""
    pass


class TimestampMixin:
    """Adds created_at and updated_at columns to any model."""

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        nullable=False,
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        onupdate=lambda: datetime.now(timezone.utc),
        nullable=False,
    )


def generate_uuid() -> str:
    """Generate a new UUID4 string. Used as default for primary keys."""
    return str(uuid.uuid4())