"""Shared FastAPI dependencies for routers.

Centralizes DB session management and API-key authentication so routers no
longer re-declare these helpers themselves.
"""

from typing import Optional

from fastapi import Depends, Header, HTTPException, status

from agenteval.config import get_settings
from agenteval.storage.db import get_session


def get_db():
    """Yield a SQLModel Session and guarantee close() on request completion."""
    session = get_session()
    try:
        yield session
    finally:
        session.close()


def require_api_key(x_api_key: Optional[str] = Header(default=None)) -> None:
    """Enforce X-API-Key header when AGENTEVAL_API_KEY is configured.

    When the setting is empty (default), the check is a no-op so local dev keeps
    working without extra configuration.
    """
    configured = get_settings().api_key
    if not configured:
        return
    if not x_api_key or x_api_key != configured:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid or missing X-API-Key",
        )


# Convenience alias used by routers via ``dependencies=[Depends(auth_required)]``.
auth_required = Depends(require_api_key)