type RateLimitBucket = {
  count: number;
  resetAt: number;
};

const globalRateLimit = globalThis as typeof globalThis & {
  __enrgeticRateLimits?: Map<string, RateLimitBucket>;
};

const buckets = globalRateLimit.__enrgeticRateLimits ?? new Map<string, RateLimitBucket>();
globalRateLimit.__enrgeticRateLimits = buckets;

export function clientAddress(request: Request) {
  const forwarded = request.headers.get("x-forwarded-for")?.split(",")[0]?.trim();
  return forwarded || request.headers.get("x-real-ip")?.trim() || "unknown";
}

export function checkRateLimit(key: string, limit: number, windowMs: number) {
  const now = Date.now();
  const current = buckets.get(key);

  if (!current || current.resetAt <= now) {
    buckets.set(key, { count: 1, resetAt: now + windowMs });
    return { allowed: true, remaining: Math.max(0, limit - 1), retryAfter: 0 };
  }

  current.count += 1;
  if (current.count > limit) {
    return {
      allowed: false,
      remaining: 0,
      retryAfter: Math.max(1, Math.ceil((current.resetAt - now) / 1000)),
    };
  }

  return { allowed: true, remaining: Math.max(0, limit - current.count), retryAfter: 0 };
}