import "dotenv/config";

const AUTH_KEY = Bun.env.TBA_AUTH_KEY;
if (!AUTH_KEY) {
  process.exit();
}

const authHeaders = new Headers({
  "X-TBA-Auth-Key": AUTH_KEY,
});

const BASE_URL = "https://www.thebluealliance.com/api/v3";

interface CacheEntry {
  etag: string;
  data: string;
  staleTime: number;
}

const tbaCache: { [name: string]: CacheEntry } = {};

interface TBAResponse {
  data: string;
  status: number;
}

function updateCache(
  endpoint: string,
  etag: string | null,
  data: string,
  maxAge: number,
) {
  if (etag) {
    tbaCache[endpoint] = { etag, data, staleTime: Date.now() + maxAge };
  }
}

function fetchCache(endpoint: string) {
  return tbaCache[endpoint];
}

async function getTBAEndpoint(endpoint: string): Promise<TBAResponse> {
  const time = Date.now();
  console.log(tbaCache[endpoint]);
  if (tbaCache[endpoint] && tbaCache[endpoint].staleTime > time) {
    console.log("Cache hit... " + endpoint);
    return { data: fetchCache(endpoint).data, status: 200 };
  }

  console.log("Fetching... " + endpoint);
  const headers = new Headers(authHeaders);
  const response = await fetch(BASE_URL + endpoint, { headers });

  let data;
  if (response.status === 200) {
    data = await response.text();
    const maxAge = parseInt(
      response.headers
        .get("cache-control")
        ?.split(",")
        .filter((d) => d.includes("max-age"))[0]
        .trim()
        .split("=")[1] as string,
    );
    updateCache(endpoint, response.headers.get("ETag"), data, maxAge);
  } else if (response.status === 304) {
    // Safety: a 304 response indicates out cache is valid based on ETag
    data = fetchCache(endpoint).data as string;

    console.log("Unchanged... " + endpoint);
  } else {
    data = "";
  }

  return {
    data,
    status: response.status,
  };
}

const response = await getTBAEndpoint("/team/frc4043/events/simple");

console.log(response);