"""SQLAlchemy models for the dashboard metadata DB.

This DB carries **only** dashboard-layer state — saved layouts, filter
presets, user prefs. arborist provenance shards stay the source of
truth and are imported read-only via ``arborist.embed`` (no SQLAlchemy
session over arborist tables, per ticket §3-corrected).
"""

from __future__ import annotations

from sqlalchemy import JSON, Column, DateTime, Integer, String, Text
from sqlalchemy.orm import declarative_base, sessionmaker
from sqlalchemy.sql import func


Base = declarative_base()


class Dashboard(Base):
    __tablename__ = "dashboards"

    id = Column(String(64), primary_key=True)
    title = Column(String(256), nullable=False)
    description = Column(Text, nullable=True)
    version = Column(String(32), nullable=False, default="dashboard-v1")
    config_json = Column(JSON, nullable=False)
    created_at = Column(DateTime, server_default=func.now())
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())


class FilterPreset(Base):
    __tablename__ = "filter_presets"

    id = Column(Integer, primary_key=True, autoincrement=True)
    dashboard_id = Column(String(64), nullable=False, index=True)
    name = Column(String(128), nullable=False)
    filter_json = Column(JSON, nullable=False)
    created_at = Column(DateTime, server_default=func.now())


def make_session_factory(engine) -> sessionmaker:
    return sessionmaker(bind=engine, expire_on_commit=False)