/**
 * @file   OpcUaMonitoredNode.cpp
 * @brief  OpcUaMonitoredNode implementation.
 */
#include "OpcUaMonitoredNode.h"
#include "OpcUaClient.h"

#include <QMetaEnum>
#include <QOpcUaLocalizedText>

OpcUaMonitoredNode::OpcUaMonitoredNode (QObject *parent) : QObject (parent) {}

/* ======================================
 *  Properties
 * ====================================== */

QString
OpcUaMonitoredNode::nodeId () const
{
  return m_nodeId;
}

void
OpcUaMonitoredNode::setNodeId (const QString &id)
{
  if (m_nodeId == id)
    return;
  m_nodeId = id;
  emit nodeIdChanged ();

  if (!m_componentComplete)
    return;

  teardownNode ();
  if (OpcUaClient::instance () && OpcUaClient::instance ()->connected ())
    setupNode ();
}

bool
OpcUaMonitoredNode::monitored () const
{
  return m_monitored;
}

void
OpcUaMonitoredNode::setMonitored (bool monitored)
{
  if (m_monitored == monitored)
    return;
  m_monitored = monitored;
  emit monitoredChanged ();
}

QVariant
OpcUaMonitoredNode::value () const
{
  return m_value;
}

OpcUaNodeInfo
OpcUaMonitoredNode::info () const
{
  return m_info;
}

/* ======================================
 *  QQmlParserStatus
 * ====================================== */

void
OpcUaMonitoredNode::classBegin ()
{
}

void
OpcUaMonitoredNode::componentComplete ()
{
  m_componentComplete = true;

  auto *client = OpcUaClient::instance ();
  if (!client)
    return;

  connect (client, &OpcUaClient::connectedChanged, this,
           &OpcUaMonitoredNode::handleClientConnectedChanged);

  if (client->connected () && !m_nodeId.isEmpty ())
    setupNode ();
}

/* ======================================
 *  Node lifecycle
 * ====================================== */

void
OpcUaMonitoredNode::setupNode ()
{
  if (m_node || m_nodeId.isEmpty ())
    return;

  auto *client = OpcUaClient::instance ();
  if (!client || !client->connected ())
    return;

  m_node = client->opcuaClient ()->node (m_nodeId);
  if (!m_node)
    return;

  m_node->setParent (this);

  connect (m_node, &QOpcUaNode::attributeUpdated, this,
           &OpcUaMonitoredNode::handleAttributeUpdated);
  connect (m_node, &QOpcUaNode::valueAttributeUpdated, this,
           &OpcUaMonitoredNode::handleValueUpdated);

  m_node->readAttributes (
      QOpcUa::NodeAttribute::Value | QOpcUa::NodeAttribute::DisplayName
      | QOpcUa::NodeAttribute::Description | QOpcUa::NodeAttribute::NodeClass
      | QOpcUa::NodeAttribute::DataType | QOpcUa::NodeAttribute::AccessLevel);
}

void
OpcUaMonitoredNode::teardownNode ()
{
  if (!m_node)
    return;

  delete m_node;
  m_node = nullptr;

  m_value.clear ();
  emit valueChanged ();

  m_info = OpcUaNodeInfo{};
  emit infoChanged ();
}

/* ======================================
 *  Signal handlers
 * ====================================== */

void
OpcUaMonitoredNode::handleAttributeUpdated (QOpcUa::NodeAttribute attr,
                                            const QVariant &value)
{
  switch (attr)
    {
    case QOpcUa::NodeAttribute::DisplayName:
      m_info.displayName = value.value<QOpcUaLocalizedText> ().text ();
      break;
    case QOpcUa::NodeAttribute::Description:
      m_info.description = value.value<QOpcUaLocalizedText> ().text ();
      break;
    case QOpcUa::NodeAttribute::NodeClass:
      {
        auto me = QMetaEnum::fromType<QOpcUa::NodeClass> ();
        auto nc = static_cast<QOpcUa::NodeClass> (value.toInt ());
        const char *key = me.valueToKey (static_cast<int> (nc));
        m_info.nodeClass
            = key ? QLatin1StringView (key) : QStringLiteral ("Unknown");
      }
      break;
    case QOpcUa::NodeAttribute::DataType:
      m_info.dataType = value.toString ();
      break;
    case QOpcUa::NodeAttribute::AccessLevel:
      m_info.accessLevel = value.toUInt ();
      break;
    default:
      return;
    }
  emit infoChanged ();
}

void
OpcUaMonitoredNode::handleValueUpdated (const QVariant &value)
{
  m_value = value;
  emit valueChanged ();

  m_info.status = QOpcUa::statusToString (m_node->valueAttributeError ());
  m_info.sourceTimestamp
      = m_node->sourceTimestamp (QOpcUa::NodeAttribute::Value);
  m_info.serverTimestamp
      = m_node->serverTimestamp (QOpcUa::NodeAttribute::Value);
  emit infoChanged ();
}

void
OpcUaMonitoredNode::handleClientConnectedChanged ()
{
  auto *client = OpcUaClient::instance ();
  if (!client)
    return;

  if (client->connected ())
    {
      if (!m_nodeId.isEmpty ())
        setupNode ();
    }
  else
    {
      teardownNode ();
    }
}