from fastapi import APIRouter, HTTPException

users = []  # In-memory storage

router = APIRouter()

@router.post("/login")
async def get_username(
    username: str = "demo"
):
    """Get username endpoint"""
    user = next((u for u in users if u["username"] == username), None)
    if not user:
        raise HTTPException(status_code=400, detail="Username not found")

    return {
        "message": "Username retrieved",
        "user": username,
        "features": {
            "rate_limit": 100,
            "expires_in": 3600
        }
    }