from typing import Dict, Any, Optional, List


def detect_anomalies_in_surveys(
    feature_cols: List[str],
    method: str = "isolation_forest",
    contamination: float = 0.02,
    group_col: Optional[str] = None
) -> Dict[str, Any]:
    """
    Detect Anomalies in Survey Responses (placeholder intent)

    Parameters
    ----------
    feature_cols : list[str]
        Numeric columns to analyze for anomalies.
    method : str
        e.g., "isolation_forest", "lof", "robust_z".
    contamination : float
        Expected proportion of anomalies.
    group_col : str | None
        Optional grouping (e.g., enumerator, district).
    """
    return {
        "type": "ml_detect_survey_anomalies",
        "method": method,
        "features_count": len(feature_cols),
        "contamination": contamination,
        "group_col": group_col,
        "preview": {"will_detect": True, "expected_outputs": ["anomaly_flags", "scores", "summary_by_group"]},
    }
