squawk/qomemo/qomemo.cpp

/*
 * Created by victoria on 2021-05-12.
 */

#include "qomemo.h"

#include <QDebug>

static bool elementMatches(const QXmppElement &element, const QString &tagName,
                           const QString &xmlns = QStringLiteral("")) {
  if (element.tagName() != tagName) {
    qWarning() << "tag name: expected = " << tagName
               << ", got = " << element.tagName();
    return false;
  }

  if (!xmlns.isEmpty() && element.attribute("xmlns") != xmlns) {
    qWarning() << "xmlns: expected = " << xmlns
               << ", got = " << element.attribute("xmlns");
    return false;
  }

  return true;
}

static QXmppElement createElement(const QString &tagName,
                                  const QString &xmlns = QStringLiteral("")) {
  QXmppElement el{};
  el.setTagName(tagName);

  if (!xmlns.isEmpty())
    el.setAttribute("xmlns", xmlns);

  return el;
}

static QXmppElement createValue(const QString &value) {
  auto el = createElement("value");
  el.setValue(value);

  return el;
}

static QXmppElement createField(const QString &key, const QString &value,
                                bool hidden = false) {
  auto field = createElement("field");
  field.setAttribute("var", key);
  if (hidden)
    field.setAttribute("type", "hidden");
  field.appendChild(createValue(value));

  return field;
}

static QXmppElement
createOpenPublishOptions(const QString &maxItems = QStringLiteral("")) {
  auto formType = createField(
      "FORM_TYPE", "http://jabber.org/protocol/pubsub#publish-options", true);
  auto accessModel = createField("pubsub#access_model", "open");

  auto x = createElement("x", "jabber:x:data");
  x.setAttribute("type", "submit");

  x.appendChild(formType);
  x.appendChild(accessModel);

  if (!maxItems.isEmpty())
    x.appendChild(createField("pubsub#max_items", maxItems));

  auto publishOptions = createElement("publish-options");
  publishOptions.appendChild(x);

  return publishOptions;
}

QXmppElement QOmemo::DeviceList::toXml() const {
  auto element = createElement("devices", "urn:xmpp:omemo:1");

  for (const auto &d : devices) {
    element.appendChild(d.toXml());
  }

  return element;
}

QXmppIq QOmemo::DeviceList::toIq() const {
  QXmppIq iq{};

  iq.setType(QXmppIq::Set);

  auto item = createElement("item");
  item.setAttribute("id", "current");
  item.appendChild(toXml());

  auto publish = createElement("publish");
  publish.setAttribute("node", "urn:xmpp:omemo:1:devices");
  publish.appendChild(item);

  auto pubSub = createElement("pubsub", "http://jabber.org/protocol/pubsub");
  pubSub.appendChild(publish);
  pubSub.appendChild(createOpenPublishOptions());

  iq.extensions().push_back(pubSub);

  return iq;
}

void QOmemo::DeviceList::fromXml(const QXmppElement &element) {
  if (!elementMatches(element, "devices", "urn:xmpp:omemo:1"))
    return;

  devices.clear();

  auto deviceElement = element.firstChildElement("device");
  while (!deviceElement.isNull()) {
    Device device{};
    device.fromXml(deviceElement);
    devices.push_back(device);

    deviceElement = deviceElement.nextSiblingElement("device");
  }
}

QXmppElement QOmemo::Device::toXml() const {
  auto result = createElement("device");
  result.setAttribute("id", QString::number(id));

  if (!label.isEmpty()) {
    result.setAttribute("label", label);
  }

  return result;
}

void QOmemo::Device::fromXml(const QXmppElement &element) {
  if (!elementMatches(element, "device"))
    return;

  id = element.attribute("id").toInt();
  label = element.attribute("label");
}

QXmppElement QOmemo::PreKey::toXml() const {
  auto pk = createElement("pk");
  pk.setAttribute("id", QString::number(id));
  // TODO: Base64
  pk.setValue(data);

  return pk;
}

void QOmemo::PreKey::fromXml(const QXmppElement &element) {
  if (!elementMatches(element, "pk"))
    return;

  id = element.attribute("id").toInt();
  // TODO: Base64
  data = element.value();
}

QXmppElement QOmemo::Bundle::toXml() const {
  auto spkNode = createElement("spk");
  spkNode.setAttribute("id", QString::number(spkId));
  spkNode.setValue(spk);

  auto spksNode = createElement("spks");
  spksNode.setValue(spks);

  auto ikNode = createElement("ik");
  ikNode.setValue(ik);

  auto prekeysNode = createElement("prekeys");
  for (const auto &pk : prekeys) {
    prekeysNode.appendChild(pk.toXml());
  }

  auto result = createElement("bundle", "urn:xmpp:omemo:1");
  result.appendChild(spkNode);
  result.appendChild(spksNode);
  result.appendChild(ikNode);
  result.appendChild(prekeysNode);

  return result;
}

QXmppIq QOmemo::Bundle::toIq() const {
  QXmppIq iq{};

  iq.setType(QXmppIq::Set);

  auto item = createElement("item");
  item.setAttribute("id", QString::number(deviceId));
  item.appendChild(toXml());

  auto publish = createElement("publish");
  publish.setAttribute("node", "urn:xmpp:omemo:1:bundles");
  publish.appendChild(item);

  auto pubSub = createElement("pubsub", "http://jabber.org/protocol/pubsub");
  pubSub.appendChild(publish);
  pubSub.appendChild(createOpenPublishOptions("max"));

  iq.extensions().push_back(pubSub);

  return iq;
}

void QOmemo::Bundle::fromXml(const QXmppElement &element) {
  if (!elementMatches(element, "bundle", "urn:xmpp:omemo:1"))
    return;

  auto spkNode = element.firstChildElement("spk");
  if (spkNode.isNull()) {
    qWarning() << "'bundle': missing 'spk'";
    return;
  }
  spk = spkNode.value();
  spkId = spkNode.attribute("id").toInt();

  auto spksNode = element.firstChildElement("spks");
  if (spksNode.isNull()) {
    qWarning() << "'bundle': missing 'spks'";
    return;
  }
  spks = spksNode.value();

  auto ikNode = element.firstChildElement("ik");
  if (ikNode.isNull()) {
    qWarning() << "'bundle': missing 'ik'";
    return;
  }
  ik = ikNode.value();

  auto prekeysNode = element.firstChildElement("prekeys");
  auto pkNode = prekeysNode.firstChildElement("pk");

  prekeys.clear();
  while (!pkNode.isNull()) {
    PreKey pk{};
    pk.fromXml(pkNode);
    prekeys.push_back(pk);
  }
}