import { SQLDataSource } from 'datasource-sql';
const { InMemoryLRUCache } = require('apollo-server-caching');
import crypto from 'crypto';

export class BaseSQLDataSource extends SQLDataSource {
  cache: any;
  constructor(config) {
    super(config);
    this.cache = config.cache || new InMemoryLRUCache();
  }

  async cacheQuery(ttl = 5, query) {
    const cacheKey = crypto
      .createHash('sha1')
      .update(query.toString())
      .digest('base64');

    return this.cache.get(cacheKey).then((entry) => {
      if (entry) {
        return Promise.resolve(JSON.parse(entry));
      }

      return query.then((rows) => {
        if (rows) {
          this.cache.set(cacheKey, JSON.stringify(rows), { ttl });
        }

        return Promise.resolve(rows);
      });
    });
  }
}