# ============================================
# Projet   : API-KA
# Fichier  : src/api/middleware/ratelimit.py
# Node     : m3u96b
# Author   : Simon-Pierre Boucher
# Contact  : contact@spboucher.ai
# Date     : 2026-08-16
# ============================================
"""Rate limiting basique par IP (défaut : 120 req/min) — l'API est publique via ngrok."""

from __future__ import annotations

import time
from collections import defaultdict, deque

from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
from starlette.requests import Request
from starlette.responses import JSONResponse, Response

from src.config import get_settings

WINDOW_SECONDS = 60.0
EXEMPT_PATHS = ("/health",)


class RateLimitMiddleware(BaseHTTPMiddleware):
    """Fenêtre glissante de 60 s par IP ; au-delà de la limite → HTTP 429."""

    def __init__(self, app, limit_per_minute: int | None = None) -> None:  # type: ignore[no-untyped-def]
        super().__init__(app)
        self.limit = limit_per_minute or get_settings().rate_limit_per_minute
        self._hits: dict[str, deque[float]] = defaultdict(deque)

    async def dispatch(
        self, request: Request, call_next: RequestResponseEndpoint
    ) -> Response:
        if request.url.path in EXEMPT_PATHS:
            return await call_next(request)

        client_ip = request.client.host if request.client else "unknown"
        now = time.monotonic()
        hits = self._hits[client_ip]
        while hits and now - hits[0] > WINDOW_SECONDS:
            hits.popleft()
        if len(hits) >= self.limit:
            return JSONResponse(
                status_code=429,
                content={
                    "success": False,
                    "error": f"Limite dépassée : {self.limit} requêtes/minute par IP",
                    "meta": {"node": get_settings().node_name},
                },
            )
        hits.append(now)
        return await call_next(request)