import { browser } from "$app/environment";
import { urljoin } from "$lib/util.js";

class API {
  constructor() {
    this.version = "v1";
  }

  // join given path and queries into an API URL
  join(path = null, query = {}) {
    let base = "";

    if (browser) {
      base = urljoin(import.meta.env.WEBSITE_API_PATH, this.version);
    } else {
      base = urljoin(import.meta.env.WEBSITE_API_URL, this.version);
    }

    return urljoin(base, path, query);
  }

  // check given JSON body for errors
  check_err(json) {
    if (!("error" in json))
      throw new Error('API response is missing the "error" key');

    if (json["error"] != "")
      throw new Error(`API returned an error: ${json["error"]}`);

    if (!("result" in json))
      throw new Error('API response is missing the "result" key');
  }

  // make a HTTP GET request to the given URL
  async GET(fetch, url) {
    const res = await fetch(url);
    const json = await res.json();
    this.check_err(json);
    return json["result"];
  }

  // get visitor metrics
  async metrics(fetch) {
    return await this.GET(fetch, this.join("/metrics"));
  }

  // get service list
  async services(fetch) {
    return await this.GET(fetch, this.join("/services"));
  }

  // get projects list
  async projects(fetch) {
    return await this.GET(fetch, this.join("/projects"));
  }
}

const api = new API();
export default api;