#ifndef FLOWGRAPHMODEL_H
#define FLOWGRAPHMODEL_H

#include <QJsonObject>
#include <QPointF>
#include <QSize>

#include <QtNodes/AbstractGraphModel>
#include <QtNodes/ConnectionIdUtils>
#include <QtNodes/StyleCollection>

using ConnectionId     = QtNodes::ConnectionId;
using ConnectionPolicy = QtNodes::ConnectionPolicy;
using NodeFlag         = QtNodes::NodeFlag;
using NodeId           = QtNodes::NodeId;
using NodeRole         = QtNodes::NodeRole;
using PortIndex        = QtNodes::PortIndex;
using PortRole         = QtNodes::PortRole;
using PortType         = QtNodes::PortType;
using StyleCollection  = QtNodes::StyleCollection;
using QtNodes::InvalidNodeId;

/**
 * The class implements a bare minimum required to demonstrate a model-based
 * graph.
 */
class FlowGraphModel : public QtNodes::AbstractGraphModel
{
    Q_OBJECT
public:
    struct NodeGeometryData
    {
        QSize size;
        QPointF pos;
    };

public:
    FlowGraphModel();

    ~FlowGraphModel() override;

    std::unordered_set<NodeId> allNodeIds() const override;

    std::unordered_set<ConnectionId> allConnectionIds(NodeId const nodeId) const override;

    std::unordered_set<ConnectionId> connections(NodeId nodeId, PortType portType, PortIndex portIndex) const override;

    bool connectionExists(ConnectionId const connectionId) const override;

    NodeId addNode(QString const nodeType = QString()) override;

    /**
     * Connection is possible when graph contains no connectivity data
     * in both directions `Out -> In` and `In -> Out`.
     */
    bool connectionPossible(ConnectionId const connectionId) const override;

    void addConnection(ConnectionId const connectionId) override;

    bool nodeExists(NodeId const nodeId) const override;

    QVariant nodeData(NodeId nodeId, NodeRole role) const override;

    bool setNodeData(NodeId nodeId, NodeRole role, QVariant value) override;

    QVariant portData(NodeId nodeId, PortType portType, PortIndex portIndex, PortRole role) const override;

    bool setPortData(NodeId nodeId, PortType portType, PortIndex portIndex, QVariant const &value,
                     PortRole role = PortRole::Data) override;

    bool deleteConnection(ConnectionId const connectionId) override;

    bool deleteNode(NodeId const nodeId) override;

    QJsonObject saveNode(NodeId const) const override;

    /// @brief Creates a new node based on the informatoin in `nodeJson`.
    /**
     * @param nodeJson conains a `NodeId`, node's position, internal node
     * information.
     */
    void loadNode(QJsonObject const &nodeJson) override;

    NodeId newNodeId() override { return _nextNodeId++; }

private:
    std::unordered_set<NodeId> _nodeIds;

    /// [Important] This is a user defined data structure backing your model.
    /// In your case it could be anything else representing a graph, for example, a
    /// table. Or a collection of structs with pointers to each other. Or an
    /// abstract syntax tree, you name it.
    ///
    /// This data structure contains the graph connectivity information in both
    /// directions, i.e. from Node1 to Node2 and from Node2 to Node1.
    std::unordered_set<ConnectionId> _connectivity;

    mutable std::unordered_map<NodeId, NodeGeometryData> _nodeGeometryData;

    /// A convenience variable needed for generating unique node ids.
    unsigned int _nextNodeId;
};

#endif  // FLOWGRAPHMODEL_H