// pull-env.ts: copy a val's environment variables into its .env on this VM.
//
//   EXPORT_TOKEN=... deno run -A pull-env.ts <export-data URL> <val dir> NAME...
//
// Reads the named variables through export-data.ts, which runs inside the
// val on Val Town, and writes them to <val dir>/.env (mode 600), replacing
// lines for the same names. Prints names only, never values.
const [base, dir, ...names] = Deno.args;
const token = Deno.env.get("EXPORT_TOKEN");
if (!base || !dir || !names.length || !token) {
  console.error("usage: EXPORT_TOKEN=... pull-env.ts <export-data URL> <val dir> NAME...");
  Deno.exit(2);
}
const u = new URL("/env", base);
u.searchParams.set("names", names.join(","));
const res = await fetch(u, { headers: { Authorization: `Bearer ${token}` } });
if (!res.ok) throw new Error(`${res.status}: ${await res.text()}`);
const values = (await res.json()) as Record<string, string>;

const file = `${dir}/.env`;
let lines: string[] = [];
try {
  lines = (await Deno.readTextFile(file)).split("\n").filter((l) => l !== "");
} catch { /* new file */ }
const todo: string[] = [];
for (const name of names) {
  const v = values[name];
  let line: string;
  // Both systemd (EnvironmentFile) and Deno (--env-file) read these forms
  // the same way: bare safe characters, or single quotes, taken literally.
  if (/^[A-Za-z0-9_\-.:\/+=@,]*$/.test(v)) line = `${name}=${v}`;
  else if (!/['\n\r]/.test(v)) line = `${name}='${v}'`;
  else {
    todo.push(name);
    continue;
  }
  lines = lines.filter((l) => !l.startsWith(`${name}=`));
  lines.push(line);
  console.log(`${name}: set`);
}
await Deno.writeTextFile(file, lines.join("\n") + "\n", { mode: 0o600 });
await Deno.chmod(file, 0o600);
if (todo.length) {
  console.log(`not written, the value has a quote or newline; set by hand: ${todo.join(", ")}`);
  Deno.exit(1);
}