Node.h

//
// TM & (c) 2017 Lucasfilm Entertainment Company Ltd. and Lucasfilm Ltd.
// All rights reserved.  See LICENSE.txt for license.
//

#ifndef MATERIALX_NODE_H
#define MATERIALX_NODE_H

/// @file
/// Node element subclasses

#include <MaterialXCore/Library.h>

#include <MaterialXCore/Definition.h>

namespace MaterialX
{

class Node;
class GraphElement;
class NodeGraph;
class Backdrop;

/// A shared pointer to a Node
using NodePtr = shared_ptr<Node>;
/// A shared pointer to a const Node
using ConstNodePtr = shared_ptr<const Node>;

/// A shared pointer to a GraphElement
using GraphElementPtr = shared_ptr<GraphElement>;
/// A shared pointer to a const GraphElement
using ConstGraphElementPtr = shared_ptr<const GraphElement>;

/// A shared pointer to a NodeGraph
using NodeGraphPtr = shared_ptr<NodeGraph>;
/// A shared pointer to a const NodeGraph
using ConstNodeGraphPtr = shared_ptr<const NodeGraph>;

/// A shared pointer to a Backdrop
using BackdropPtr = shared_ptr<Backdrop>;
/// A shared pointer to a const Backdrop
using ConstBackdropPtr = shared_ptr<const Backdrop>;

// Predicate to test a node against some criteria whether
// that criteria has passed
using NodePredicate = std::function<bool(NodePtr node)>;

/// @class Node
/// A node element within a NodeGraph or Document.
///
/// A Node represents an instance of a NodeDef within a graph, and its Input
/// elements apply specific values and connections to that instance.
class Node : public InterfaceElement
{
  public:
    Node(ElementPtr parent, const string& name) :
        InterfaceElement(parent, CATEGORY, name)
    {
    }
    virtual ~Node() { }

    /// @name Connections
    /// @{

    /// Set the node to which the given input is connected, creating a
    /// child input if needed.  If the node argument is null, then any
    /// existing node connection on the input will be cleared.
    void setConnectedNode(const string& inputName, NodePtr node);

    /// Return the Node connected to the given input.  If the given input is
    /// not present, then an empty NodePtr is returned.
    NodePtr getConnectedNode(const string& inputName) const;

    /// Set the name of the Node connected to the given input, creating a child
    /// element for the input if needed.
    void setConnectedNodeName(const string& inputName, const string& nodeName);

    /// Return the name of the Node connected to the given input.  If the given
    /// input is not present, then an empty string is returned.
    string getConnectedNodeName(const string& inputName) const;

    /// Set the output to which the given input is connected, creating a
    /// child input if needed.  If the node argument is null, then any
    /// existing output connection on the input will be cleared.
    void setConnectedOutput(const string& inputName, OutputPtr output);

    /// Return the output connected to the given input.  If the given input is
    /// not present, then an empty OutputPtr is returned.
    OutputPtr getConnectedOutput(const string& inputName) const;

    /// @}
    /// @name NodeDef References
    /// @{

    /// Return the first NodeDef that declares this node, optionally filtered
    /// by the given target name.
    /// @param target An optional target name, which will be used to filter
    ///    the nodedefs that are considered.
    /// @return A NodeDef for this node, or an empty shared pointer if none
    ///    was found.
    NodeDefPtr getNodeDef(const string& target = EMPTY_STRING) const;

    /// @}
    /// @name Implementation References
    /// @{

    /// Return the first implementation for this node, optionally filtered by
    /// the given target and language names.
    /// @param target An optional target name, which will be used to filter
    ///    the implementations that are considered.
    /// @return An implementation for this node, or an empty shared pointer if
    ///    none was found.  Note that a node implementation may be either an
    ///    Implementation element or a NodeGraph element.
    InterfaceElementPtr getImplementation(const string& target = EMPTY_STRING) const
    {
        NodeDefPtr nodeDef = getNodeDef(target);
        return nodeDef ? nodeDef->getImplementation(target) : InterfaceElementPtr();
    }

    /// @}
    /// @name Traversal
    /// @{

    /// Return the Edge with the given index that lies directly upstream from
    /// this element in the dataflow graph.
    Edge getUpstreamEdge(size_t index = 0) const override;

    /// Return the number of queriable upstream edges for this element.
    size_t getUpstreamEdgeCount() const override
    {
        return getInputCount();
    }

    /// Given a connecting element (Input or Output) return the NodeDef output
    /// corresponding to the output the element is connected to. This is only valid if
    /// the NodeDef has explicit outputs defined, e.g. multiple outputs or an explicitly 
    /// named output. If this is not the case, nullptr is returned, which implies the
    /// node is a standard node with a single implicit output.
    OutputPtr getNodeDefOutput(ElementPtr connectingElement);

    /// Return a vector of all downstream ports that connect to this node, ordered by
    /// the names of the port elements.
    vector<PortElementPtr> getDownstreamPorts() const;

    /// @}
    /// @name Utility
    /// @{

    /// Return the first declaration of this interface, optionally filtered
    ///    by the given target name.
    ConstNodeDefPtr getDeclaration(const string& target = EMPTY_STRING) const override
    {
        return getNodeDef(target);
    }

    /// Add an input based on the corresponding input for the associated node definition.
    /// If the input already exists on the node it will just be returned.
    ValueElementPtr addInputFromNodeDef(const string& name);

    /// @}
    /// @name Validation
    /// @{

    /// Validate that the given element tree, including all descendants, is
    /// consistent with the MaterialX specification.
    bool validate(string* message = nullptr) const override;

    /// @}

  public:
    static const string CATEGORY;
};

/// @class GraphElement
/// The base class for graph elements such as NodeGraph and Document.
class GraphElement : public InterfaceElement
{
  protected:
    GraphElement(ElementPtr parent, const string& category, const string& name) :
        InterfaceElement(parent, category, name)
    {
    }
  public:
    virtual ~GraphElement() { }

    /// @name Node Elements
    /// @{

    /// Add a Node to the graph.
    /// @param category The category of the new Node.
    /// @param name The name of the new Node.
    ///     If no name is specified, then a unique name will automatically be
    ///     generated.
    /// @param type An optional type string.
    /// @return A shared pointer to the new Node.
    NodePtr addNode(const string& category,
                    const string& name = EMPTY_STRING,
                    const string& type = DEFAULT_TYPE_STRING)
    {
        NodePtr node = addChild<Node>(name);
        node->setCategory(category);
        node->setType(type);
        return node;
    }

    /// Add a Node that is an instance of the given NodeDef.
    NodePtr addNodeInstance(ConstNodeDefPtr nodeDef, const string& name = EMPTY_STRING)
    {
        NodePtr node = addNode(nodeDef->getNodeString(), name, nodeDef->getType());
        node->setNodeDefString(nodeDef->getName());
        return node;
    }

    /// Return the Node, if any, with the given name.
    NodePtr getNode(const string& name) const
    {
        return getChildOfType<Node>(name);
    }

    /// Return a vector of all Nodes in the graph, optionally filtered by the
    /// given category string.
    vector<NodePtr> getNodes(const string& category = EMPTY_STRING) const
    {
        return getChildrenOfType<Node>(category);
    }

    /// Return a vector of nodes in the graph which have a given type
    vector<NodePtr> getNodesOfType(const string& nodeType) const
    {
        vector<NodePtr> nodes;
        for (auto node : getNodes())
        {
            if (node->getType() == nodeType)
            {
                nodes.push_back(node);
            }
        }
        return nodes;
    }

    /// Remove the Node, if any, with the given name.
    void removeNode(const string& name)
    {
        removeChildOfType<Node>(name);
    }

    /// @}
    /// @name Material Nodes
    /// @{

    /// Add a material node to the graph, optionally connecting it to the given
    /// shader node.
    NodePtr addMaterialNode(const string& name = EMPTY_STRING, ConstNodePtr shaderNode = nullptr);

    /// Return a vector of all material nodes.
    vector<NodePtr> getMaterialNodes() const
    {
        return getNodesOfType(MATERIAL_TYPE_STRING);
    }

    /// @}
    /// @name Backdrop Elements
    /// @{

    /// Add a Backdrop to the graph.
    BackdropPtr addBackdrop(const string& name = EMPTY_STRING)
    {
        return addChild<Backdrop>(name);
    }

    /// Return the Backdrop, if any, with the given name.
    BackdropPtr getBackdrop(const string& name) const
    {
        return getChildOfType<Backdrop>(name);
    }

    /// Return a vector of all Backdrop elements in the graph.
    vector<BackdropPtr> getBackdrops() const
    {
        return getChildrenOfType<Backdrop>();
    }

    /// Remove the Backdrop, if any, with the given name.
    void removeBackdrop(const string& name)
    {
        removeChildOfType<Backdrop>(name);
    }

    /// @}
    /// @name Utility
    /// @{

    /// Flatten any references to graph-based node definitions within this
    /// node graph, replacing each reference with the equivalent node network.
    void flattenSubgraphs(const string& target = EMPTY_STRING, NodePredicate filter=nullptr);

    /// Return a vector of all children (nodes and outputs) sorted in
    /// topological order.
    /// @throws ExceptionFoundCycle if a cycle is encountered.
    vector<ElementPtr> topologicalSort() const;

    /// Convert this graph to a string in the DOT language syntax.  This can be
    /// used to visualise the graph using GraphViz (http://www.graphviz.org).
    ///
    /// If declarations for the contained nodes are provided as nodedefs in
    /// the owning document, then they will be used to provide additional
    /// formatting details.
    string asStringDot() const;

    /// @}
};

/// @class NodeGraph
/// A node graph element within a Document.
class NodeGraph : public GraphElement
{
  public:
    NodeGraph(ElementPtr parent, const string& name) :
        GraphElement(parent, CATEGORY, name)
    {
    }
    virtual ~NodeGraph() { }

    /// @name NodeDef References
    /// @{

    /// Set the NodeDef element referenced by this NodeGraph.
    void setNodeDef(ConstNodeDefPtr nodeDef);

    /// Return the NodeDef element referenced by this NodeGraph.
    NodeDefPtr getNodeDef() const;

    /// Return the first implementation for this node graph
    /// @return An implementation for this node, or an empty shared pointer if
    ///    none was found.  
    InterfaceElementPtr getImplementation() const;

    /// @}
    /// @name Utility
    /// @{

    /// Return the first declaration of this interface, optionally filtered
    ///    by the given target name.
    ConstNodeDefPtr getDeclaration(const string& target = EMPTY_STRING) const override;

    /// Add an interface name to an existing NodeDef associated with this NodeGraph.
    /// @param inputPath Path to an input descendant of this graph.
    /// @param interfaceName The new interface name.
    void addInterfaceName(const string& inputPath, const string& interfaceName);

    /// Remove an interface name from an existing NodeDef associated with this NodeGraph.
    /// @param inputPath Path to an input descendant of this graph.
    void removeInterfaceName(const string& inputPath);

    /// Modify the interface name on an existing NodeDef associated with this NodeGraph.
    /// @param inputPath Path to an input descendant of this graph.
    /// @param interfaceName The new interface name.
    void modifyInterfaceName(const string& inputPath, const string& interfaceName);

    /// @}
    /// @name Validation
    /// @{

    /// Validate that the given element tree, including all descendants, is
    /// consistent with the MaterialX specification.
    bool validate(string* message = nullptr) const override;

    /// @}

  public:
    static const string CATEGORY;
};

/// @class Backdrop
/// A layout element used to contain, group and document nodes within a graph.
class Backdrop : public Element
{
  public:
    Backdrop(ElementPtr parent, const string& name) :
        Element(parent, CATEGORY, name)
    {
    }
    virtual ~Backdrop() { }

    /// @name Contains String
    /// @{

    /// Set the contains string for this backdrop.
    void setContainsString(const string& contains)
    {
        setAttribute(CONTAINS_ATTRIBUTE, contains);
    }

    /// Return true if this backdrop has a contains string.
    bool hasContainsString() const
    {
        return hasAttribute(CONTAINS_ATTRIBUTE);
    }

    /// Return the contains string for this backdrop.
    string getContainsString() const
    {
        return getAttribute(CONTAINS_ATTRIBUTE);
    }

    /// @}
    /// @name Width
    /// @{

    /// Set the width attribute of the backdrop.
    void setWidth(float width)
    {
        setTypedAttribute<float>(WIDTH_ATTRIBUTE, width);
    }

    /// Return true if this backdrop has a width attribute.
    bool hasWidth() const
    {
        return hasAttribute(WIDTH_ATTRIBUTE);
    }

    /// Return the width attribute of the backdrop.
    float getWidth() const
    {
        return getTypedAttribute<float>(WIDTH_ATTRIBUTE);
    }

    /// @}
    /// @name Height
    /// @{

    /// Set the height attribute of the backdrop.
    void setHeight(float height)
    {
        setTypedAttribute<float>(HEIGHT_ATTRIBUTE, height);
    }

    /// Return true if this backdrop has a height attribute.
    bool hasHeight() const
    {
        return hasAttribute(HEIGHT_ATTRIBUTE);
    }

    /// Return the height attribute of the backdrop.
    float getHeight() const
    {
        return getTypedAttribute<float>(HEIGHT_ATTRIBUTE);
    }

    /// @}
    /// @name Utility
    /// @{

    /// Set the vector of elements that this backdrop contains.
    void setContainsElements(const vector<ConstTypedElementPtr>& nodes);

    /// Return the vector of elements that this backdrop contains.
    vector<TypedElementPtr> getContainsElements() const;

    /// @}
    /// @name Validation
    /// @{

    /// Validate that the given element tree, including all descendants, is
    /// consistent with the MaterialX specification.
    bool validate(string* message = nullptr) const override;

    /// @}

  public:
    static const string CATEGORY;
    static const string CONTAINS_ATTRIBUTE;
    static const string WIDTH_ATTRIBUTE;
    static const string HEIGHT_ATTRIBUTE;
};

} // namespace MaterialX

#endif