import { ref } from "vue";

import * as cache from "../utils/cache";
import * as cachePromise from "../utils/cachePromise";

import { Plugin } from "../types";

const useCachePlugin: Plugin<any, any[]> = (
  fetchInstance,
  { cacheKey, cacheTime = 5 * 60 * 1000, staleTime = 0 }
) => {
  const currentPromiseRef = ref<Promise<any>>();

  if (!cacheKey) return {};

  const cacheData = cache.getCache(cacheKey);
  console.log("cacheData: ", cacheData);
  fetchInstance.state.data = cacheData?.data;
  fetchInstance.state.params = cacheData?.params;

  return {
    onBefore: () => {
      const cacheData = cache.getCache(cacheKey);
      console.log("cacheData: ", cacheData);
      // 首次未缓存
      if (!cacheData) return {};

      if (Date.now() - cacheData.time <= staleTime) {
        // 当前缓存新鲜，无需再请求
        return {
          loading: false,
          data: cacheData.data,
          returnNow: true,
        };
      } else {
        return {
          data: cacheData.data,
        };
      }
    },
    onRequest: (service, params) => {
      let servicePromise = cachePromise.getCachePromise(cacheKey);

      // 请求 Promise 共享，相同的 cacheKey 同时只会有一个在发起请求，后发起的会共用同一个请求 Promise
      if (servicePromise && servicePromise !== currentPromiseRef.value) {
        return { servicePromise };
      }

      servicePromise = service(...params);
      currentPromiseRef.value = servicePromise;
      cachePromise.setCachePromise(cacheKey, servicePromise);

      return { servicePromise };
    },
    onSuccess: (data, params) => {
      if (cacheKey) {
        cache.setCache(cacheKey, cacheTime, data, params);
      }
    },
  };
};

export default useCachePlugin;