"""Reusable column mixins.

- ``UUIDPrimaryKey`` — UUID surrogate key (no PII in URLs; safe for multi-tenant).
- ``Timestamps``     — created/updated audit timestamps (DB-managed).
- ``SoftDelete``     — ``deleted_at``; a row is "deleted" when set. A scheduled
                       worker purges rows past the 30-day window (PRD US-080/081).
- ``TenantScoped``   — ``tree_id`` FK; every tree-owned row carries it so the
                       privacy engine can enforce isolation uniformly.
"""

import uuid
from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, func
from sqlalchemy.orm import Mapped, declared_attr, mapped_column


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


class Timestamps:
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        onupdate=func.now(),
        nullable=False,
    )


class SoftDelete:
    deleted_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True, default=None
    )


class TenantScoped:
    @declared_attr
    def tree_id(cls) -> Mapped[uuid.UUID]:  # noqa: N805
        return mapped_column(
            ForeignKey("trees.id", ondelete="CASCADE"), nullable=False, index=True
        )