from contextlib import asynccontextmanager

from fastapi import FastAPI, Request, Response
from fastapi.middleware.cors import CORSMiddleware
from prometheus_client import CONTENT_TYPE_LATEST, Counter, Histogram, generate_latest
from slowapi import Limiter
from slowapi.errors import RateLimitExceeded
from slowapi.middleware import SlowAPIMiddleware
from slowapi.util import get_remote_address
from starlette.responses import JSONResponse

from app.api import admin, oidc, public
from app.core.config import get_settings
from app.core.database import create_all
from app.core.security import load_or_create_oidc_key

settings = get_settings()
REQUESTS = Counter("nexamfa_http_requests_total", "HTTP requests", ["method", "path", "status"])
LATENCY = Histogram("nexamfa_http_request_duration_seconds", "HTTP request latency", ["method", "path"])
limiter = Limiter(key_func=get_remote_address, default_limits=[settings.rate_limit_default])


@asynccontextmanager
async def lifespan(app: FastAPI):
    oidc.set_oidc_private_key(load_or_create_oidc_key(settings.oidc_signing_key_pem))
    await create_all()
    yield


app = FastAPI(title="NexaMFA", version="0.1.0", lifespan=lifespan)
app.state.limiter = limiter
app.add_middleware(SlowAPIMiddleware)
app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.cors_origin_list,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.exception_handler(RateLimitExceeded)
async def rate_limit_handler(_: Request, exc: RateLimitExceeded):
    return JSONResponse({"detail": "Rate limit exceeded"}, status_code=429)


@app.middleware("http")
async def metrics_middleware(request: Request, call_next):
    with LATENCY.labels(request.method, request.url.path).time():
        response = await call_next(request)
    REQUESTS.labels(request.method, request.url.path, str(response.status_code)).inc()
    return response


@app.get("/health")
async def health():
    return {"status": "ok", "service": "NexaMFA"}


@app.get("/metrics")
async def metrics():
    return Response(generate_latest(), media_type=CONTENT_TYPE_LATEST)


app.include_router(public.router)
app.include_router(admin.router)
app.include_router(oidc.router)