import type { SyncStore } from '@/app/store/sync';
import { STORAGE_KEY } from '@/app/constant';
import { chunks } from '../format';

export type UpstashConfig = SyncStore['upstash'];
export type UpStashClient = ReturnType<typeof createUpstashClient>;

export function createUpstashClient(store: SyncStore) {
  const config = store.upstash;
  const storeKey = config.username.length === 0 ? STORAGE_KEY : config.username;
  const chunkCountKey = `${storeKey}-chunk-count`;
  const chunkIndexKey = (i: number) => `${storeKey}-chunk-${i}`;

  const proxyUrl
    = store.useProxy && store.proxyUrl.length > 0 ? store.proxyUrl : undefined;

  return {
    async check() {
      try {
        const res = await fetch(this.path(`get/${storeKey}`, proxyUrl), {
          method: 'GET',
          headers: this.headers(),
        });
        console.log('[Upstash] check', res.status, res.statusText);
        return [200].includes(res.status);
      } catch (e) {
        console.error('[Upstash] failed to check', e);
      }
      return false;
    },

    async redisGet(key: string) {
      const res = await fetch(this.path(`get/${key}`, proxyUrl), {
        method: 'GET',
        headers: this.headers(),
      });

      console.log('[Upstash] get key = ', key, res.status, res.statusText);
      const resJson = (await res.json()) as { result: string };

      return resJson.result;
    },

    async redisSet(key: string, value: string) {
      const res = await fetch(this.path(`set/${key}`, proxyUrl), {
        method: 'POST',
        headers: this.headers(),
        body: value,
      });

      console.log('[Upstash] set key = ', key, res.status, res.statusText);
    },

    async get() {
      const chunkCount = Number(await this.redisGet(chunkCountKey));
      if (!Number.isInteger(chunkCount))
      { return; }

      const chunks = await Promise.all(
        new Array(chunkCount)
          .fill(0)
          .map((_, i) => this.redisGet(chunkIndexKey(i))),
      );
      console.log('[Upstash] get full chunks', chunks);
      return chunks.join('');
    },

    async set(_: string, value: string) {
      // upstash limit the max request size which is 1Mb for “Free” and “Pay as you go”
      // so we need to split the data to chunks
      let index = 0;
      for await (const chunk of chunks(value)) {
        await this.redisSet(chunkIndexKey(index), chunk);
        index += 1;
      }
      await this.redisSet(chunkCountKey, index.toString());
    },

    headers() {
      return {
        Authorization: `Bearer ${config.apiKey}`,
      };
    },
    path(path: string, proxyUrl: string = '') {
      if (!path.endsWith('/')) {
        path += '/';
      }
      if (path.startsWith('/')) {
        path = path.slice(1);
      }

      if (proxyUrl.length > 0 && !proxyUrl.endsWith('/')) {
        proxyUrl += '/';
      }

      let url;
      const pathPrefix = '/api/upstash/';

      try {
        const u = new URL(proxyUrl + pathPrefix + path);
        // add query params
        u.searchParams.append('endpoint', config.endpoint);
        url = u.toString();
      } catch (e) {
        url = `${pathPrefix + path}?endpoint=${config.endpoint}`;
      }

      return url;
    },
  };
}