diff -r 9ab78e08a34c -r a3ad06ac390e qmlfrontend/net_session.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/qmlfrontend/net_session.cpp	Sat May 11 22:39:55 2019 +0200
@@ -0,0 +1,137 @@
+#include "net_session.h"
+
+NetSession::NetSession(QObject *parent) : QObject(parent) {}
+
+QUrl NetSession::url() const { return m_url; }
+
+QAbstractSocket::SocketState NetSession::state() const {
+  if (m_socket)
+    return m_socket->state();
+  else
+    return QAbstractSocket::UnconnectedState;
+}
+
+void NetSession::open() {
+  m_socket.reset(new QTcpSocket());
+
+  connect(m_socket.data(), &QAbstractSocket::stateChanged, this,
+          &NetSession::stateChanged);
+  connect(m_socket.data(), &QTcpSocket::readyRead, this,
+          &NetSession::onReadyRead);
+
+  m_socket->connectToHost(m_url.host(),
+                          static_cast<quint16>(m_url.port(46631)));
+}
+
+QString NetSession::nickname() const { return m_nickname; }
+
+QString NetSession::password() const { return m_password; }
+
+NetSession::SessionState NetSession::sessionState() const {
+  return m_sessionState;
+}
+
+void NetSession::setUrl(const QUrl &url) {
+  if (m_url == url) return;
+
+  m_url = url;
+  emit urlChanged(m_url);
+}
+
+void NetSession::setNickname(const QString &nickname) {
+  if (m_nickname == nickname) return;
+
+  m_nickname = nickname;
+  emit nicknameChanged(m_nickname);
+}
+
+void NetSession::setPassword(const QString &password) {
+  if (m_password == password) return;
+
+  m_password = password;
+  emit passwordChanged(m_password);
+}
+
+void NetSession::close() {
+  if (!m_socket.isNull()) {
+    m_socket->disconnectFromHost();
+    m_socket.clear();
+
+    setSessionState(NotConnected);
+  }
+}
+
+void NetSession::onReadyRead() {
+  while (m_socket->canReadLine()) {
+    auto line = QString::fromUtf8(m_socket->readLine().simplified());
+
+    if (line.isEmpty()) {
+      parseNetMessage(m_buffer);
+      m_buffer.clear();
+    } else {
+      m_buffer.append(line);
+    }
+  }
+}
+
+void NetSession::parseNetMessage(const QStringList &message) {
+  if (message.isEmpty()) {
+    qWarning() << "Empty net message received";
+    return;
+  }
+
+  qDebug() << "[SERVER]" << message;
+
+  using Handler = std::function<void(NetSession *, const QStringList &)>;
+  static QMap<QString, Handler> commandsMap{
+      {"CONNECTED", &NetSession::handleConnected},
+      {"PING", &NetSession::handlePing},
+      {"BYE", &NetSession::handleBye}};
+
+  auto handler =
+      commandsMap.value(message[0], &NetSession::handleUnknownCommand);
+
+  handler(this, message.mid(1));
+}
+
+void NetSession::handleConnected(const QStringList &parameters) {
+  setSessionState(Login);
+}
+
+void NetSession::handlePing(const QStringList &parameters) {
+  send("PONG", parameters);
+}
+
+void NetSession::handleBye(const QStringList &parameters) { close(); }
+
+void NetSession::handleUnknownCommand(const QStringList &parameters) {
+  Q_UNUSED(parameters);
+
+  qWarning() << "Command is not recognized";
+}
+
+void NetSession::send(const QString &message) { send(QStringList(message)); }
+
+void NetSession::send(const QString &message, const QString &param) {
+  send(QStringList{message, param});
+}
+
+void NetSession::send(const QString &message, const QStringList &parameters) {
+  send(QStringList(message) + parameters);
+}
+
+void NetSession::send(const QStringList &message) {
+  Q_ASSERT(!m_socket.isNull());
+
+  qDebug() << "[CLIENT]" << message;
+
+  m_socket->write(message.join('\n').toUtf8() + "\n\n");
+}
+
+void NetSession::setSessionState(NetSession::SessionState sessionState) {
+  if (m_sessionState == sessionState) return;
+
+  m_sessionState = sessionState;
+
+  emit sessionStateChanged(sessionState);
+}