from fastapi import FastAPI, Request
import time

app = FastAPI()

request_count = 0
last_response_time_ms = 0.0


@app.middleware("http")
async def track_requests(request: Request, call_next):
    """
    Measures the REAL processing time of every request using a middleware
    that wraps the actual handler, instead of measuring time inside the
    handler itself (which always returns ~0ms).
    We skip counting calls to /stats itself so the dashboard polling
    doesn't inflate the request counter.
    """
    global request_count, last_response_time_ms

    start = time.time()
    response = await call_next(request)
    duration_ms = round((time.time() - start) * 1000, 2)

    if request.url.path != "/stats":
        request_count += 1
        last_response_time_ms = duration_ms

    return response


@app.get("/")
def home():
    return {"message": "Application is running"}


@app.get("/health")
def health():
    return {"status": "UP"}


@app.get("/stats")
def stats():
    return {
        "status": "UP",
        "requests": request_count,
        "response_time": last_response_time_ms
    }