/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* vim: set sts=2 sw=2 et tw=80: */
"use strict";

const dnssFlags = {
  "allow_name_collisions": Ci.nsIDNSService.RESOLVE_ALLOW_NAME_COLLISION,
  "bypass_cache": Ci.nsIDNSService.RESOLVE_BYPASS_CACHE,
  "canonical_name": Ci.nsIDNSService.RESOLVE_CANONICAL_NAME,
  "disable_ipv4": Ci.nsIDNSService.RESOLVE_DISABLE_IPV4,
  "disable_ipv6": Ci.nsIDNSService.RESOLVE_DISABLE_IPV6,
  "disable_trr": Ci.nsIDNSService.RESOLVE_DISABLE_TRR,
  "offline": Ci.nsIDNSService.RESOLVE_OFFLINE,
  "priority_low": Ci.nsIDNSService.RESOLVE_PRIORITY_LOW,
  "priority_medium": Ci.nsIDNSService.RESOLVE_PRIORITY_MEDIUM,
  "speculate": Ci.nsIDNSService.RESOLVE_SPECULATE,
};

function getErrorString(nsresult) {
  let e = new Components.Exception("", nsresult);
  return e.name;
}

this.dns = class extends ExtensionAPI {
  getAPI(context) {
    const dnss = Cc["@mozilla.org/network/dns-service;1"].getService(Ci.nsIDNSService);
    return {
      dns: {
        resolve: function(hostname, flags) {
          let dnsFlags = flags.reduce((mask, flag) => mask | dnssFlags[flag], 0);

          return new Promise((resolve, reject) => {
            let request;
            let response = {
              addresses: [],
            };
            let listener = {
              onLookupComplete: function(inRequest, inRecord, inStatus) {
                if (inRequest === request) {
                  if (!Components.isSuccessCode(inStatus)) {
                    return reject({message: getErrorString(inStatus)});
                  }
                  if (dnsFlags & Ci.nsIDNSService.RESOLVE_CANONICAL_NAME) {
                    try {
                      response.canonicalName = inRecord.canonicalName;
                    } catch (e) {
                      // no canonicalName
                    }
                  }
                  response.isTRR = inRecord.IsTRR();
                  while (inRecord.hasMore()) {
                    let addr = inRecord.getNextAddrAsString();
                    // Sometimes there are duplicate records with the same ip.
                    if (!response.addresses.includes(addr)) {
                      response.addresses.push(addr);
                    }
                  }
                  return resolve(response);
                }
              },
            };
            try {
              request = dnss.asyncResolve(hostname, dnsFlags, listener, null, {} /* defaultOriginAttributes */);
            } catch (e) {
              // handle exceptions such as offline mode.
              return reject({message: e.name});
            }
          });
        },
      },
    };
  }
};