/**
 * @file network-config.js
 * @description The dashboard's saved network settings — bind address(es),
 * allowed Host names and the dashboard token — in `<data dir>/network.json`
 * (0600). `agenthub start --host/--allowed-hosts/--token` writes it; every
 * server start (a restart after an update, the autostart unit, the plugin
 * bootstrap) applies it with `applyNetworkConfig()`, so a wider bind no longer
 * falls back to loopback silently the next time something else starts the
 * server. An environment variable that is set always wins over the file.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
const fs = require("node:fs");
const path = require("node:path");
const crypto = require("node:crypto");

/** File key → the environment variable it stands in for. */
const KEYS = {
  host: "DASHBOARD_HOST",
  allowedHosts: "DASHBOARD_ALLOWED_HOSTS",
  token: "DASHBOARD_TOKEN",
};

function configPath() {
  const { getDataDir } = require("./claude-home");
  return path.join(getDataDir(), "network.json");
}

/** The saved settings, `{}` when there are none (or the file is unreadable). */
function readNetworkConfig() {
  try {
    const c = JSON.parse(fs.readFileSync(configPath(), "utf8"));
    if (!c || typeof c !== "object" || Array.isArray(c)) return {};
    const out = {};
    for (const k of Object.keys(KEYS)) {
      if (typeof c[k] === "string" && c[k].trim()) out[k] = c[k].trim();
    }
    return out;
  } catch {
    return {};
  }
}

/**
 * Merge `patch` into the saved settings: a string sets a key, `null` removes
 * it. Written 0600 through a temp file. Returns the new settings.
 */
function writeNetworkConfig(patch) {
  const next = { ...readNetworkConfig() };
  for (const [k, v] of Object.entries(patch)) {
    if (!(k in KEYS)) continue;
    if (v === null || v === "") delete next[k];
    else next[k] = String(v).trim();
  }
  const file = configPath();
  fs.mkdirSync(path.dirname(file), { recursive: true });
  const tmp = `${file}.${process.pid}.tmp`;
  fs.writeFileSync(tmp, `${JSON.stringify(next, null, 2)}\n`, { mode: 0o600 });
  fs.chmodSync(tmp, 0o600);
  fs.renameSync(tmp, file);
  return next;
}

/** Put every saved setting whose environment variable is unset into `env`. */
function applyNetworkConfig(env = process.env) {
  const saved = readNetworkConfig();
  for (const [k, name] of Object.entries(KEYS)) {
    if (saved[k] && !(typeof env[name] === "string" && env[name].trim())) env[name] = saved[k];
  }
  return saved;
}

/** A fresh random token for `--token auto`. */
const newToken = () => crypto.randomBytes(24).toString("base64url");

module.exports = {
  configPath,
  readNetworkConfig,
  writeNetworkConfig,
  applyNetworkConfig,
  newToken,
  KEYS,
};