from __future__ import annotations

from typing import ClassVar, Optional

from sqlmodel import Field, SQLModel


class MaterialRow(SQLModel, table=True):
    """Defensive view of the externally-owned ``material`` catalogue table.

    Declares only the columns the modelling backend reads to price a Measure
    Option; other columns (r-values, labour breakdowns, etc.) are left off so
    schema churn elsewhere doesn't ripple in. `total_cost` is the fully-loaded
    cost per the row's `cost_unit` (GBP/m^2 for fabric measures).
    """

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

    id: int = Field(primary_key=True)
    type: str
    total_cost: Optional[float] = Field(default=None)
    cost_unit: Optional[str] = Field(default=None)
    description: Optional[str] = Field(default=None)
    is_active: bool = Field(default=True)