"""ORM model for roundtable-planning business chains.

A "business chain" (业务链条) is a named, reusable, *ordered* list of agents the
user assembles in the chain editor. In Step 2 the coordinator dispatches to the
seats following this order (see ``multi-agent-business-chain-dev.md``).

Persisted per user (like ``roundtable_drafts``) so it follows the account across
devices/sessions. ``seats`` is stored as a JSON array serialized into
``PortableLongText`` (MySQL ``LONGTEXT``) rather than ``PortableJSON`` for
headroom, mirroring the sibling roundtable persistence modules.
"""

from __future__ import annotations

from datetime import UTC, datetime

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

from deerflow.persistence.base import Base
from deerflow.persistence.types import BeijingDateTime, PortableLongText


class RoundtableChainRow(Base):
    __tablename__ = "roundtable_chains"

    id: Mapped[str] = mapped_column(String(64), primary_key=True)
    user_id: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
    # Human-readable chain title shown on the picker card.
    title: Mapped[str] = mapped_column(String(512), nullable=False, default="")
    # Optional free-text description.
    description: Mapped[str | None] = mapped_column(String(2048), nullable=True)
    # JSON: ordered [{"agent_id": str, "name": str, "description": str}, ...].
    # seats[0] is the first seat to speak. Stored as LONGTEXT-backed JSON string.
    seats: Mapped[str | None] = mapped_column(PortableLongText, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        BeijingDateTime(), nullable=False, default=lambda: datetime.now(UTC)
    )
    updated_at: Mapped[datetime] = mapped_column(
        BeijingDateTime(),
        nullable=False,
        default=lambda: datetime.now(UTC),
        onupdate=lambda: datetime.now(UTC),
    )