"""Scoring what was trained."""

from __future__ import annotations

import json

import fluksio
from fluksio import Port, node


def score(lr: float, epochs: int) -> float:
    """How good the model came out, with no Fluksio in it."""
    return round(1 - lr / (1 + epochs), 4)


@node(requires=["weights"], provides=Port("score", "float"))
def evaluate(weights):
    """Score the model, returning the number rather than a dict.

    `provides=Port(...)` — one port rather than a list of them — is the opt-in
    to a bare return: the generated node wraps it in the message it belongs to.
    """
    trained = json.loads(open(fluksio.load_artifact(weights)).read())
    return score(trained["lr"], trained["epochs"])