#pragma once

#include "Node.hpp"
#include "Connection.hpp"

namespace QtNodes
{

class DataModelRegistry;
class FlowScene;
class NodeDataModel;

/// Class performs various operations on the Node and Connection pair.
/// An instance should be created on the stack and destroyed when
/// the operation is completed
class NodeConnectionInteraction
{
public:
  NodeConnectionInteraction(Node& node,
                            Connection& connection,
                            FlowScene& scene);

  /// Can connect when following conditions are met:
  /// 1) Connection 'requires' a port
  /// 2) Connection's vacant end is above the node port
  /// 3) Node port is vacant
  /// 4) Connection type equals node port type, or there is a registered type conversion that can translate between the two
  bool
  canConnect(PortIndex & portIndex,
             TypeConverter & converter) const;

  /// 1)   Check conditions from 'canConnect'
  /// 1.5) If the connection is possible but a type conversion is needed, add a converter node to the scene, and connect it properly
  /// 1.6) Check for cyclic connection.
  /// 2)   Assign node to required port in Connection
  /// 3)   Assign Connection to empty port in NodeState
  /// 4)   Adjust Connection geometry
  /// 5)   Poke model to initiate data transfer
  bool
  tryConnect() const;

  /// 1) Node and Connection should be already connected
  /// 2) If so, clear Connection entry in the NodeState
  /// 3) Propagate invalid data to IN node
  /// 4) Set Connection end to 'requiring a port'
  bool
  disconnect(PortType portToDisconnect) const;

private:

  PortType
  connectionRequiredPort() const;
  
  QPointF connectionStartScenePosition(PortType) const;

  QPointF connectionEndScenePosition(PortType) const;

  QPointF
  nodePortScenePosition(PortType portType,
                        PortIndex portIndex) const;

  PortIndex
  nodePortIndexUnderScenePoint(PortType portType,
                               QPointF const &p) const;

  bool
  nodePortIsEmpty(PortType portType, PortIndex portIndex) const;

private:

  Node* _node;

  Connection* _connection;

  FlowScene* _scene;
};
}