import json
import os
from pathlib import Path


def _schema_path() -> Path:
    base = Path(__file__).resolve().parents[1]
    return base / "schemas" / "event.json"


def validate_event(event: dict) -> None:
    if os.environ.get("JAMES_VALIDATE_SCHEMA", "1") != "1":
        return

    try:
        import jsonschema
    except Exception as exc:  # pragma: no cover - runtime guard
        raise RuntimeError(f"jsonschema is required for validation: {exc}")

    schema = json.loads(_schema_path().read_text())
    jsonschema.validate(instance=event, schema=schema)