"""EntityAttachment model — references DMS files for any entity."""

from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, Index, String
from sqlalchemy.dialects.postgresql import UUID as PGUUID
from sqlalchemy.orm import Mapped, mapped_column

from app.core.db import Base, TenantMixin
from app.models.owned_mixin import OwnedMixin


class EntityAttachment(Base, TenantMixin, OwnedMixin):
    """Links a DMS file to any entity (contact, address, invoice, etc.).
    
    The actual file is stored in the DMS (files table).
    This table only holds the reference + category + display_name.
    """

    __tablename__ = "entity_attachments"
    __table_args__ = (
        Index("ix_entity_attachments_entity", "entity_type", "entity_id", "tenant_id"),
        Index("ix_entity_attachments_dms_file", "dms_file_id"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    entity_type: Mapped[str] = mapped_column(String(50), nullable=False)
    entity_id: Mapped[uuid.UUID] = mapped_column(PGUUID(as_uuid=True), nullable=False)
    dms_file_id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True),
        ForeignKey("files.id", ondelete="RESTRICT"),
        nullable=False,
    )
    category: Mapped[str | None] = mapped_column(String(50), nullable=True)
    display_name: Mapped[str | None] = mapped_column(String(255), nullable=True)
    created_by: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=__import__('sqlalchemy').func.now()
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=__import__('sqlalchemy').func.now(),
        onupdate=__import__('sqlalchemy').func.now(),
    )
    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)