/**
 * DNS provider configuration serialisation — shared by the setup wizard
 * (browser global DnsProviderConfig) and the backend parity tests
 * (module.exports), so the wizard→builder field mapping is tested by the
 * exact code that ships (DC-171 phase 2, judge r6 blocker).
 */
(function (root) {
  'use strict';

  // Per-provider API/DNS port defaults. The generic wizard port field
  // historically meant "Technitium API port" (5380); PowerDNS and RFC2136
  // have their own defaults that must apply when the user leaves it empty.
  var PROVIDER_PORT_DEFAULTS = {
    powerdns: 8081, // PowerDNS webserver/API port
    rfc2136: 53,    // RFC 2136 speaks DNS itself
  };

  function normalizePort(rawPort) {
    var s = String(rawPort == null ? '' : rawPort).trim();
    if (!/^\d{1,5}$/.test(s)) return null; // full-string digits only (no "9090junk")
    var n = parseInt(s, 10);
    return n >= 1 && n <= 65535 ? n : null; // valid TCP/UDP range
  }

  /**
   * Build the config.dns object from the wizard's DNS provider step.
   *
   * @param {string} selectedProvider - technitium|cloudflare|powerdns|rfc2136|manual
   * @param {string} ip               - server IP from the form
   * @param {string} rawPort          - raw port field (may be empty/whitespace)
   * @param {string} token            - API key / TSIG-adjacent secret from the form
   * @param {number} defaultDnsPort   - legacy generic default (Technitium API, 5380)
   * @returns {Object} config.dns — generic fields PLUS provider-specific aliases
   */
  function buildDnsConfig(selectedProvider, ip, rawPort, token, defaultDnsPort) {
    var portRaw = normalizePort(rawPort);
    var providerDefault = PROVIDER_PORT_DEFAULTS[selectedProvider] || null;
    // explicit input > provider default > legacy generic default
    var port = portRaw != null ? portRaw : (providerDefault || defaultDnsPort);

    var dns = {
      provider: selectedProvider,
      ip: String(ip == null ? '' : ip).trim(),
      port: port,
      token: String(token == null ? '' : token).trim(),
    };

    // Provider-specific aliases so the server-side config builders receive
    // the field names they read (generic ip/port/token stay for the
    // technitium path and the confirmation summary)
    if (selectedProvider === 'powerdns') {
      dns.server = dns.ip;
      dns.apiPort = dns.port;
      dns.dnsPort = 53;
      dns.apiToken = dns.token;
    } else if (selectedProvider === 'rfc2136') {
      dns.server = dns.ip;
      dns.port = dns.port; // already defaulted to 53 above
    }

    return dns;
  }

  var api = { buildDnsConfig: buildDnsConfig, PROVIDER_PORT_DEFAULTS: PROVIDER_PORT_DEFAULTS };

  if (typeof module === 'object' && module.exports) {
    module.exports = api;            // node (tests)
  } else {
    root.DnsProviderConfig = api;    // browser (setup wizard)
  }
})(typeof self !== 'undefined' ? self : this);