"""ContactFolder model — hierarchical folders for organizing contacts.

Supports nested folders via parent_id, per-user ownership, and sort_order
for manual ordering via drag & drop.
"""

from __future__ import annotations

import uuid
from datetime import datetime

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

from app.core.db import Base, TenantMixin


class ContactFolder(Base, TenantMixin):
    """Hierarchical folder for organizing contacts.

    Folders are tenant-scoped and user-owned. A folder with parent_id=NULL
    is a root folder. sort_order controls display order within the same parent.
    """

    __tablename__ = "contact_folders"
    __table_args__ = (
        Index("ix_contact_folders_tenant_parent", "tenant_id", "parent_id"),
        Index("ix_contact_folders_user", "user_id"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    name: Mapped[str] = mapped_column(String(255), nullable=False)
    parent_id: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True),
        ForeignKey("contact_folders.id", ondelete="CASCADE"),
        nullable=True,
    )
    user_id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    sort_order: Mapped[int] = mapped_column(Integer, nullable=False, default=0, server_default="0")

    # ── Relationships ──
    parent: Mapped[ContactFolder | None] = relationship(
        "ContactFolder",
        remote_side="ContactFolder.id",
        back_populates="children",
    )
    children: Mapped[list[ContactFolder]] = relationship(
        "ContactFolder",
        back_populates="parent",
        cascade="all, delete-orphan",
        order_by="ContactFolder.sort_order",
    )