metrics_evaluation/config/config_loader.py

"""Configuration loader with validation."""

import json
from pathlib import Path

from .config_models import EvaluationConfig


def load_config(config_path: str | Path) -> EvaluationConfig:
    """Load and validate configuration from JSON file.

    Args:
        config_path: Path to configuration JSON file

    Returns:
        Validated EvaluationConfig instance

    Raises:
        FileNotFoundError: If config file doesn't exist
        ValueError: If configuration is invalid
    """
    path = Path(config_path)

    if not path.exists():
        raise FileNotFoundError(
            f"Configuration file not found: {config_path}\n"
            f"Please create config file at: {path.absolute()}"
        )

    try:
        with open(path, "r") as f:
            config_dict = json.load(f)
    except json.JSONDecodeError as e:
        raise ValueError(f"Invalid JSON in config file {config_path}: {e}") from e

    try:
        config = EvaluationConfig(**config_dict)
    except Exception as e:
        raise ValueError(f"Configuration validation failed: {e}") from e

    return config