@app.command()
def evaluate(
    run_id: Annotated[str, typer.Option(help="id of the specific run to load from")] = None,
    dataset_loc: Annotated[str, typer.Option(help="dataset (with labels) to evaluate on")] = None,
    results_fp: Annotated[str, typer.Option(help="location to save evaluation results to")] = None,
) -> Dict:  # pragma: no cover, eval workload
    """Evaluate on the holdout dataset.

    Args:
        run_id (str): id of the specific run to load from. Defaults to None.
        dataset_loc (str): dataset (with labels) to evaluate on.
        results_fp (str, optional): location to save evaluation results to. Defaults to None.

    Returns:
        Dict: model's performance metrics on the dataset.
    """
    # Load
    ds = ray.data.read_csv(dataset_loc)
    best_checkpoint = predict.get_best_checkpoint(run_id=run_id)
    predictor = TorchPredictor.from_checkpoint(best_checkpoint)

    # y_true
    preprocessor = predictor.get_preprocessor()
    y_true = utils.get_col(preprocessor.transform(ds), col="targets")

    # y_pred
    z = predictor.predict(data=ds.to_pandas())["predictions"]
    y_pred = np.stack(z).argmax(1)

    # Metrics
    metrics = {
        "timestamp": datetime.datetime.now().strftime("%B %d, %Y %I:%M:%S %p"),
        "run_id": run_id,
        "overall": get_overall_metrics(y_true=y_true, y_pred=y_pred),
        "per_class": get_per_class_metrics(y_true=y_true, y_pred=y_pred, class_to_index=preprocessor.class_to_index),
        "slices": get_slice_metrics(y_true=y_true, y_pred=y_pred, ds=ds),
    }
    logger.info(json.dumps(metrics, indent=2))
    if results_fp:  # pragma: no cover, saving results
        utils.save_dict(d=metrics, path=results_fp)
    return metrics

def get_overall_metrics(y_true: np.ndarray, y_pred: np.ndarray) -> Dict:  # pragma: no cover, eval workload
    """Get overall performance metrics.

    Args:
        y_true (np.ndarray): ground truth labels.
        y_pred (np.ndarray): predicted labels.

    Returns:
        Dict: overall metrics.
    """
    metrics = precision_recall_fscore_support(y_true, y_pred, average="weighted")
    overall_metrics = {
        "precision": metrics[0],
        "recall": metrics[1],
        "f1": metrics[2],
        "num_samples": np.float64(len(y_true)),
    }
    return overall_metrics

def get_per_class_metrics(y_true: np.ndarray, y_pred: np.ndarray, class_to_index: Dict) -> Dict:  # pragma: no cover, eval workload
    """Get per class performance metrics.

    Args:
        y_true (np.ndarray): ground truth labels.
        y_pred (np.ndarray): predicted labels.
        class_to_index (Dict): dictionary mapping class to index.

    Returns:
        Dict: per class metrics.
    """
    per_class_metrics = {}
    metrics = precision_recall_fscore_support(y_true, y_pred, average=None)
    for i, _class in enumerate(class_to_index):
        per_class_metrics[_class] = {
            "precision": metrics[0][i],
            "recall": metrics[1][i],
            "f1": metrics[2][i],
            "num_samples": np.float64(metrics[3][i]),
        }
    sorted_per_class_metrics = OrderedDict(sorted(per_class_metrics.items(), key=lambda tag: tag[1]["f1"], reverse=True))
    return sorted_per_class_metrics

def get_slice_metrics(y_true: np.ndarray, y_pred: np.ndarray, ds: Dataset) -> Dict:  # pragma: no cover, eval workload
    """Get performance metrics for slices.

    Args:
        y_true (np.ndarray): ground truth labels.
        y_pred (np.ndarray): predicted labels.
        ds (Dataset): Ray dataset with labels.
        preprocessor (Preprocessor): Ray preprocessor.

    Returns:
        Dict: performance metrics for slices.
    """
    slice_metrics = {}
    df = ds.to_pandas()
    df["text"] = df["title"] + " " + df["description"]
    slices = PandasSFApplier([nlp_llm, short_text]).apply(df)
    for slice_name in slices.dtype.names:
        mask = slices[slice_name].astype(bool)
        if sum(mask):
            metrics = precision_recall_fscore_support(y_true[mask], y_pred[mask], average="micro")
            slice_metrics[slice_name] = {}
            slice_metrics[slice_name]["precision"] = metrics[0]
            slice_metrics[slice_name]["recall"] = metrics[1]
            slice_metrics[slice_name]["f1"] = metrics[2]
            slice_metrics[slice_name]["num_samples"] = len(y_true[mask])
    return slice_metrics

@slicing_function()
def nlp_llm(x):  # pragma: no cover, eval workload
    """NLP projects that use LLMs."""
    nlp_project = "natural-language-processing" in x.tag
    llm_terms = ["transformer", "llm", "bert"]
    llm_project = any(s.lower() in x.text.lower() for s in llm_terms)
    return nlp_project and llm_project

@slicing_function()
def short_text(x):  # pragma: no cover, eval workload
    """Projects with short titles and descriptions."""
    return len(x.text.split()) < 8  # less than 8 words