from __future__ import annotations

from typing import ClassVar, Optional

from sqlmodel import Field, SQLModel

from domain.modelling.scenario import Scenario


class ScenarioRow(SQLModel, table=True):
    """SQLModel mirror of the live ``scenario`` table (ADR-0017).

    Declares only the columns the Modelling stage reads — the legacy
    file-path columns (`trigger_file_path`, `exclusions`, …) and the
    portfolio-level aggregates are left to the legacy SQLAlchemy model
    (`backend/app/db/models/recommendations.py::ScenarioModel`), which still
    owns the live reads. The physical table is the shared contract; this
    mirror is read-only from the rebuild's side.

    `goal` is a Postgres enum in production; mapped here as its string value
    (the Modelling stage does not yet branch on it — #1160).
    """

    __tablename__: ClassVar[str] = "scenario"  # pyright: ignore[reportIncompatibleVariableOverride]

    id: Optional[int] = Field(default=None, primary_key=True)
    goal: str
    goal_value: str
    budget: Optional[float] = Field(default=None)
    is_default: bool = Field(default=False)

    def to_domain(self) -> Scenario:
        if self.id is None:
            raise ValueError("scenario row has no id")
        return Scenario(
            id=self.id,
            goal=self.goal,
            goal_value=self.goal_value,
            budget=self.budget,
            is_default=self.is_default,
        )