const token = process.env.GITHUB_TOKEN;
const server = process.env.GITHUB_SERVER_URL;
const repo = process.env.GITHUB_REPOSITORY;
const pr = process.env.PR_NUMBER;
const sha = process.env.GITHUB_SHA;
const marker = process.env.MARKER ?? "<!-- amalgolopoly-preview -->";
const shortSha = sha ? sha.slice(0, 7) : null;
const body =
  process.env.BODY ??
  [
    marker,
    "### Preview deployment",
    `https://amalgolopoly.lschaefer.xyz/pr-${pr}/`,
    shortSha
      ? `\nDeployed commit: [\`${shortSha}\`](${server}/${repo}/commit/${sha})`
      : "",
  ]
    .filter(Boolean)
    .join("\n");

if (!token || !server || !repo || !pr) {
  console.error(
    "GITHUB_TOKEN, GITHUB_SERVER_URL, GITHUB_REPOSITORY, and PR_NUMBER are required",
  );
  process.exit(1);
}

const api = `${server}/api/v1/repos/${repo}`;
const headers = {
  Authorization: `token ${token}`,
  "Content-Type": "application/json",
};

async function req(method, url, data) {
  const res = await fetch(url, { method, headers, body: data });
  if (!res.ok) {
    throw new Error(`${method} ${url}: ${res.status} ${await res.text()}`);
  }
  return res.status === 204 ? null : res.json();
}

const comments = await req("GET", `${api}/issues/${pr}/comments?limit=100`);
const existing = comments.find((c) => (c.body || "").includes(marker));
const payload = JSON.stringify({ body });

if (existing) {
  await req("PATCH", `${api}/issues/comments/${existing.id}`, payload);
  console.log(`Updated preview comment ${existing.id}`);
} else {
  await req("POST", `${api}/issues/${pr}/comments`, payload);
  console.log("Created preview comment");
}