import { lstatSync, readFileSync } from "node:fs";
import { join } from "node:path";
import { BINDING_NAME } from "../../discord/src/binding.mjs";
import { CliError } from "./errors.mjs";

// The notifier's private config: `<dataRoot>/notify/<business>/notify.json`,
// 0600, `{"notifyVersion": 1, "binding": "<discord binding>" | null}`.
// Missing refuses, so a host never starts without someone deciding whether
// it DMs; null runs the host without a notifier. Refusals name the business
// and the path under the data root, never the host path (PR #1916).
export function readNotifyConfig(dataRoot, business) {
  const file = join(dataRoot, "notify", business, "notify.json");
  let st;
  try {
    st = lstatSync(file);
  } catch {
    throw new CliError(`no notifier config for ${business}: write {"notifyVersion": 1, "binding": "<discord binding>"} to notify/${business}/notify.json under the data root, mode 0600, or "binding": null to run without DMs`, 3);
  }
  if (!st.isFile() || st.uid !== process.getuid() || (st.mode & 0o777) !== 0o600) {
    throw new CliError(`notifier config for ${business} must be a regular file, mode 0600, owned by this user`, 3);
  }
  let doc;
  try {
    doc = JSON.parse(readFileSync(file, "utf8"));
  } catch {
    throw new CliError(`notifier config for ${business} is not JSON`, 3);
  }
  const keys = doc && typeof doc === "object" && !Array.isArray(doc) ? Object.keys(doc).sort().join(",") : "";
  if (keys !== "binding,notifyVersion" || doc.notifyVersion !== 1 || (doc.binding !== null && !(typeof doc.binding === "string" && BINDING_NAME.test(doc.binding)))) {
    throw new CliError(`notifier config for ${business} must be exactly {"notifyVersion": 1, "binding": <binding name> | null}`, 3);
  }
  return doc.binding;
}