import { createServer } from "node:http";
import { appendFileSync, readFileSync, writeFileSync, existsSync } from "node:fs";

const [clientId, clientSecret] = process.argv.slice(2);
if (!clientId || !clientSecret) {
  console.error("usage: node scripts/spotify-auth.mjs <CLIENT_ID> <CLIENT_SECRET>");
  process.exit(1);
}

const REDIRECT = "http://127.0.0.1:8888/callback";
const SCOPE = "user-read-currently-playing user-read-recently-played user-top-read";

const authUrl =
  "https://accounts.spotify.com/authorize?" +
  new URLSearchParams({
    client_id: clientId,
    response_type: "code",
    redirect_uri: REDIRECT,
    scope: SCOPE,
  });

console.log("\n1. open this in your browser and approve:\n\n" + authUrl + "\n");
console.log("2. waiting for the redirect on " + REDIRECT + " ...\n");

const server = createServer(async (req, res) => {
  const url = new URL(req.url, "http://127.0.0.1:8888");
  if (url.pathname !== "/callback") {
    res.writeHead(404).end();
    return;
  }
  const code = url.searchParams.get("code");
  const err = url.searchParams.get("error");
  if (err || !code) {
    res.writeHead(400).end("no code (" + (err || "missing") + ")");
    server.close();
    process.exit(1);
  }

  const tokenRes = await fetch("https://accounts.spotify.com/api/token", {
    method: "POST",
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      Authorization: "Basic " + Buffer.from(`${clientId}:${clientSecret}`).toString("base64"),
    },
    body: new URLSearchParams({
      grant_type: "authorization_code",
      code,
      redirect_uri: REDIRECT,
    }),
  });
  const data = await tokenRes.json();

  if (!data.refresh_token) {
    res.writeHead(500).end("token exchange failed: " + JSON.stringify(data));
    console.error("\ntoken exchange failed:\n", data);
    server.close();
    process.exit(1);
  }

  const block =
    `\nSPOTIFY_CLIENT_ID=${clientId}\n` +
    `SPOTIFY_CLIENT_SECRET=${clientSecret}\n` +
    `SPOTIFY_REFRESH_TOKEN=${data.refresh_token}\n`;

  if (existsSync(".dev.vars")) {
    const cur = readFileSync(".dev.vars", "utf8").replace(/^SPOTIFY_[A-Z_]+=.*$/gm, "").replace(/\n{3,}/g, "\n\n");
    writeFileSync(".dev.vars", cur.trimEnd() + "\n" + block);
  } else {
    appendFileSync(".dev.vars", block);
  }

  res.writeHead(200, { "Content-Type": "text/plain" }).end("done — you can close this tab.");
  console.log("wrote SPOTIFY_CLIENT_ID / SPOTIFY_CLIENT_SECRET / SPOTIFY_REFRESH_TOKEN to .dev.vars\n");
  console.log("for prod, run:");
  console.log("  npx wrangler secret put SPOTIFY_CLIENT_ID");
  console.log("  npx wrangler secret put SPOTIFY_CLIENT_SECRET");
  console.log("  npx wrangler secret put SPOTIFY_REFRESH_TOKEN\n");
  server.close();
  process.exit(0);
});

server.listen(8888, "127.0.0.1");