"""
API Dependencies — Shared dependency injection for all routes.
"""

import secrets

from fastapi import Header, HTTPException, Request

from config import get_settings
from core.gateway import AIPSTNGateway


def get_gateway(request: Request) -> AIPSTNGateway:
    """Get the gateway instance from app state."""
    gateway = getattr(request.app.state, "gateway", None)
    if gateway is None:
        raise HTTPException(status_code=503, detail="Gateway not initialized")
    return gateway


def get_routing_service(request: Request):
    """Get the routing service from app state."""
    routing = getattr(request.app.state, "routing_service", None)
    if routing is None:
        raise HTTPException(status_code=503, detail="Routing service not ready")
    return routing


def require_token(authorization: str | None = Header(default=None)) -> None:
    """
    Enforce the static bearer token (API_TOKEN) on REST routes.

    An empty configured token disables auth; startup refuses that
    combination unless the server is bound to loopback.
    """
    token = get_settings().api_token.get_secret_value()
    if not token:
        return
    supplied = ""
    if authorization and authorization.lower().startswith("bearer "):
        supplied = authorization[7:]
    if not secrets.compare_digest(supplied, token):
        raise HTTPException(
            status_code=401,
            detail="Missing or invalid bearer token",
            headers={"WWW-Authenticate": "Bearer"},
        )