nuxt-app/app/composables/useAgentRateLimit.ts

import { ref, computed } from "vue";

export interface RateLimitInfo {
  sessionRemaining: number | null;
  ipRemaining: number | null;
}

export function useAgentRateLimit() {
  const sessionRemaining = ref<number | null>(null);
  const ipRemaining = ref<number | null>(null);

  const isBlocked = computed(
    () =>
      sessionRemaining.value !== null && sessionRemaining.value === 0,
  );
  const isIpBlocked = computed(
    () => ipRemaining.value !== null && ipRemaining.value === 0,
  );
  const isLimited = computed(() => isBlocked.value || isIpBlocked.value);

  function updateFromHeaders(headers: Headers) {
    const sr = headers.get("X-RateLimit-Session-Remaining");
    const ir = headers.get("X-RateLimit-Ip-Remaining");
    if (sr !== null) sessionRemaining.value = Number(sr);
    if (ir !== null) ipRemaining.value = Number(ir);
  }

  function reset() {
    sessionRemaining.value = null;
    ipRemaining.value = null;
  }

  return {
    sessionRemaining,
    ipRemaining,
    isBlocked,
    isIpBlocked,
    isLimited,
    updateFromHeaders,
    reset,
  };
}