/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * OpenSceneGraph Public License for more details.
*/


#ifndef OSG_NODE
#define OSG_NODE 1

#include <osg/Object>
#include <osg/StateSet>
#include <osg/BoundingSphere>
#include <osg/NodeCallback>

#include <string>
#include <vector>

namespace osg {

class NodeVisitor;
class Group;
class Transform;
class Node;

/** A vector of Nodes pointers which is used to describe the path from a root node to a descendant.*/
typedef std::vector< Node* > NodePath;

/** A vector of NodePath, typically used to describe all the paths from a node to the potential root nodes it has.*/
typedef std::vector< NodePath > NodePathList;

/** A vector of NodePath, typically used to describe all the paths from a node to the potential root nodes it has.*/
typedef std::vector< Matrix > MatrixList;

/** META_Node macro define the standard clone, isSameKindAs, className
  * and accept methods.  Use when subclassing from Node to make it
  * more convenient to define the required pure virtual methods.*/
#define META_Node(library,name) \
        virtual osg::Object* cloneType() const { return new name (); } \
        virtual osg::Object* clone(const osg::CopyOp& copyop) const { return new name (*this,copyop); } \
        virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const name *>(obj)!=NULL; } \
        virtual const char* className() const { return #name; } \
        virtual const char* libraryName() const { return #library; } \
        virtual void accept(osg::NodeVisitor& nv) { if (nv.validNodeMask(*this)) { nv.pushOntoNodePath(this); nv.apply(*this); nv.popFromNodePath(); } } \
        

/** Base class for all internal nodes in the scene graph.
    Provides interface for most common node operations (Composite Pattern).
*/
class OSG_EXPORT Node : public Object
{
    public:

        /** Construct a node.
            Initialize the parent list to empty, node name to "" and 
            bounding sphere dirty flag to true.*/
        Node();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        Node(const Node&,const CopyOp& copyop=CopyOp::SHALLOW_COPY);

        /** clone an object of the same type as the node.*/
        virtual Object* cloneType() const { return new Node(); }

        /** return a clone of a node, with Object* return type.*/
        virtual Object* clone(const CopyOp& copyop) const { return new Node(*this,copyop); }

        /** return true if this and obj are of the same kind of object.*/
        virtual bool isSameKindAs(const Object* obj) const { return dynamic_cast<const Node*>(obj)!=NULL; }

        /** return the name of the node's library.*/
        virtual const char* libraryName() const { return "osg"; }

        /** return the name of the node's class type.*/
        virtual const char* className() const { return "Node"; }

        /** convert 'this' into a Group pointer if Node is a Group, otherwise return 0.
          * Equivalent to dynamic_cast<Group*>(this).*/
        virtual Group* asGroup() { return 0; }
        /** convert 'const this' into a const Group pointer if Node is a Group, otherwise return 0.
          * Equivalent to dynamic_cast<const Group*>(this).*/
        virtual const Group* asGroup() const { return 0; }

        /** Convert 'this' into a Transform pointer if Node is a Transform, otherwise return 0.
          * Equivalent to dynamic_cast<Transform*>(this).*/
        virtual Transform* asTransform() { return 0; }

        /** convert 'const this' into a const Transform pointer if Node is a Transform, otherwise return 0.
          * Equivalent to dynamic_cast<const Transform*>(this).*/
        virtual const Transform* asTransform() const { return 0; }

        /** Visitor Pattern : calls the apply method of a NodeVisitor with this node's type.*/
        virtual void accept(NodeVisitor& nv);
        /** Traverse upwards : calls parents' accept method with NodeVisitor.*/
        virtual void ascend(NodeVisitor& nv);
        /** Traverse downwards : calls children's accept method with NodeVisitor.*/
        virtual void traverse(NodeVisitor& /*nv*/) {}       

        /** A vector of osg::Group pointers which is used to store the parent(s) of node.*/
        typedef std::vector<Group*> ParentList;

        /** Get the parent list of node. */
        inline const ParentList& getParents() const { return _parents; }

        /** Get the a copy of parent list of node. A copy is returned to 
          * prevent modification of the parent list.*/
        inline ParentList getParents() { return _parents; }

        inline Group* getParent(unsigned int i)  { return _parents[i]; }

        /**
         * Get a single const parent of node.
         * @param i index of the parent to get.
         * @return the parent i.
         */
        inline const Group* getParent(unsigned int i) const  { return _parents[i]; }

        /**
         * Get the number of parents of node.
         * @return the number of parents of this node.
         */
        inline unsigned int getNumParents() const { return _parents.size(); }

        /** Get the list of node paths parent paths.
          * The optional Node* haltTraversalAtNode allows the user to prevent traversal beyond a specifed node. */
        NodePathList getParentalNodePaths(osg::Node* haltTraversalAtNode=0) const;

        /** Get the list of matrices that transform this node from local coordinates to world coordinates.
          * The optional Node* haltTraversalAtNode allows the user to prevent traversal beyond a specifed node. */
        MatrixList getWorldMatrices(const osg::Node* haltTraversalAtNode=0) const;
        

        /** Set update node callback, called during update traversal. */
        void setUpdateCallback(NodeCallback* nc);

        /** Get update node callback, called during update traversal. */
        inline NodeCallback* getUpdateCallback() { return _updateCallback.get(); }

        /** Get const update node callback, called during update traversal. */
        inline const NodeCallback* getUpdateCallback() const { return _updateCallback.get(); }

        /** Get the number of Children of this node which require Update traversal,
          * since they have an Update Callback attached to them or their children.*/
        inline unsigned int getNumChildrenRequiringUpdateTraversal() const { return _numChildrenRequiringUpdateTraversal; }


        /** Set update node callback, called during update traversal. */
        void setEventCallback(NodeCallback* nc);

        /** Get update node callback, called during update traversal. */
        inline NodeCallback* getEventCallback() { return _eventCallback.get(); }

        /** Get const update node callback, called during update traversal. */
        inline const NodeCallback* getEventCallback() const { return _eventCallback.get(); }

        /** Get the number of Children of this node which require Event traversal,
          * since they have an Event Callback attached to them or their children.*/
        inline unsigned int getNumChildrenRequiringEventTraversal() const { return _numChildrenRequiringEventTraversal; }


        /** Set cull node callback, called during cull traversal. */
        void setCullCallback(NodeCallback* nc) { _cullCallback = nc; }

        /** Get cull node callback, called during cull traversal. */
        inline NodeCallback* getCullCallback() { return _cullCallback.get(); }

        /** Get const cull node callback, called during cull traversal. */
        inline const NodeCallback* getCullCallback() const { return _cullCallback.get(); }

        /** Set the view frustum/small feature culling of this node to be active or inactive.
          * The default value is true for _cullingActive. Used as a guide
          * to the cull traversal.*/
        void setCullingActive(bool active);

        /** Get the view frustum/small feature _cullingActive flag for this node. Used as a guide
          * to the cull traversal.*/
        inline bool getCullingActive() const { return _cullingActive; }

        /** Get the number of Children of this node which have culling disabled.*/
        inline unsigned int getNumChildrenWithCullingDisabled() const { return _numChildrenWithCullingDisabled; }

        /** Return true if this node can be culled by view frustum, occlusion or small feature culling during the cull traversal.
          * Note, returns true only if no children have culling disabled, and the local _cullingActive flag is true.*/
        inline bool isCullingActive() const { return _numChildrenWithCullingDisabled==0 && _cullingActive && getBound().valid(); }

        /** Get the number of Children of this node which are or have OccluderNode's.*/
        inline unsigned int getNumChildrenWithOccluderNodes() const { return _numChildrenWithOccluderNodes; }

        
        /** return true if this node is an OccluderNode or the subgraph below this node are OccluderNodes.*/
        bool containsOccluderNodes() const;


        typedef unsigned int NodeMask;
        /** Set the node mask.*/
        inline void setNodeMask(NodeMask nm) { _nodeMask = nm; }
        /** Get the node Mask.*/
        inline NodeMask getNodeMask() const { return _nodeMask; }



        /** A vector of std::string's which are used to describe the object.*/
        typedef std::vector<std::string> DescriptionList;

        /** Set the description list of the node.*/        
        inline void setDescriptions(const DescriptionList& descriptions) { _descriptions=descriptions; }

        /** Get the description list of the node.*/        
        inline DescriptionList& getDescriptions() { return _descriptions; }

        /** Get the const description list of the const node.*/        
        inline const DescriptionList& getDescriptions() const { return _descriptions; }

        /** Get a single const description of the const node.*/
        inline const std::string& getDescription(unsigned int i) const { return _descriptions[i]; }

        /** Get a single description of the node.*/
        inline std::string& getDescription(unsigned int i) { return _descriptions[i]; }

        /** Get the number of descriptions of the node.*/
        inline unsigned int getNumDescriptions() const { return _descriptions.size(); }

        /** Add a description string to the node.*/
        void addDescription(const std::string& desc) { _descriptions.push_back(desc); }


        /** Set the node's StateSet.*/
        void setStateSet(osg::StateSet* stateset);

        /** return the node's StateSet, if one does not already exist create it
          * set the node and return the newly created StateSet. This ensures
          * that a valid StateSet is always returned and can be used directly.*/
        osg::StateSet* getOrCreateStateSet();

        /** Return the node's StateSet. returns NULL if a stateset is not attached.*/
        inline osg::StateSet* getStateSet() { return _stateset.get(); }

        /** Return the node's const StateSet. Returns NULL if a stateset is not attached.*/
        inline const osg::StateSet* getStateSet() const { return _stateset.get(); }

        /** Set the initial bounding volume to use when computing the overall bounding volume.*/
        void setInitialBound(const osg::BoundingSphere& bsphere) { _initialBound = bsphere; dirtyBound(); }

        /** Set the initial bounding volume to use when computing the overall bounding volume.*/
        const BoundingSphere& getInitialBound() const { return _initialBound; }

        /** Mark this node's bounding sphere dirty.
            Forcing it to be computed on the next call to getBound().*/
        void dirtyBound();

        /** Get the bounding sphere of node.
           Using lazy evaluation computes the bounding sphere if it is 'dirty'.*/
        inline const BoundingSphere& getBound() const
        {
            if(!_boundingSphereComputed)
            {
                _boundingSphere = _initialBound;
                if (_computeBoundCallback.valid()) 
                    _boundingSphere.expandBy(_computeBoundCallback->computeBound(*this));
                else
                    _boundingSphere.expandBy(computeBound());
                    
                _boundingSphereComputed = true;
            }
            return _boundingSphere;
        }


        /** Compute the bounding sphere around Node's geometry or children.
            This method is automatically called by getBound() when the bounding
            sphere has been marked dirty via dirtyBound().*/
        virtual BoundingSphere computeBound() const;

        /** Callback to allow users to override the default computation of bounding volume.*/
        struct ComputeBoundingSphereCallback : public osg::Object
        {
            ComputeBoundingSphereCallback() {}

            ComputeBoundingSphereCallback(const ComputeBoundingSphereCallback&,const CopyOp&) {}

            META_Object(osg,ComputeBoundingSphereCallback);

           virtual BoundingSphere computeBound(const osg::Node&) const { return BoundingSphere(); }
        };

        /** Set the compute bound callback to override the default computeBound.*/
        void setComputeBoundingSphereCallback(ComputeBoundingSphereCallback* callback) { _computeBoundCallback = callback; }

        /** Get the compute bound callback.*/
        ComputeBoundingSphereCallback* getComputeBoundingSphereCallback() { return _computeBoundCallback.get(); }

        /** Get the const compute bound callback.*/
        const ComputeBoundingSphereCallback* getComputeBoundingSphereCallback() const { return _computeBoundCallback.get(); }

        /** Set whether to use a mutex to ensure ref() and unref() are thread safe.*/
        virtual void setThreadSafeRefUnref(bool threadSafe);

        /** Resize any per context GLObject buffers to specified size. */
        virtual void resizeGLObjectBuffers(unsigned int /*maxSize*/);

        /** If State is non-zero, this function releases any associated OpenGL objects for
           * the specified graphics context. Otherwise, releases OpenGL objects
           * for all graphics contexts. */
        virtual void releaseGLObjects(osg::State* = 0) const;


    protected:

        /** Node destructor. Note, is protected so that Nodes cannot
            be deleted other than by being dereferenced and the reference
            count being zero (see osg::Referenced), preventing the deletion
            of nodes which are still in use. This also means that
            Nodes cannot be created on stack i.e Node node will not compile,
            forcing all nodes to be created on the heap i.e Node* node
            = new Node().*/
        virtual ~Node();



        BoundingSphere                          _initialBound;
        ref_ptr<ComputeBoundingSphereCallback>  _computeBoundCallback;
        mutable BoundingSphere                  _boundingSphere;
        mutable bool                            _boundingSphereComputed;

        void addParent(osg::Group* node);
        void removeParent(osg::Group* node);

        ParentList _parents;
        friend class osg::Group;
        friend class osg::Drawable;
        friend class osg::StateSet;

        ref_ptr<NodeCallback> _updateCallback;
        unsigned int _numChildrenRequiringUpdateTraversal;
        void setNumChildrenRequiringUpdateTraversal(unsigned int num);

        ref_ptr<NodeCallback> _eventCallback;
        unsigned int _numChildrenRequiringEventTraversal;
        void setNumChildrenRequiringEventTraversal(unsigned int num);

        ref_ptr<NodeCallback> _cullCallback;

        bool _cullingActive;
        unsigned int _numChildrenWithCullingDisabled;        
        void setNumChildrenWithCullingDisabled(unsigned int num);

        unsigned int _numChildrenWithOccluderNodes;        
        void setNumChildrenWithOccluderNodes(unsigned int num);

        NodeMask _nodeMask;
        
        DescriptionList _descriptions;

        ref_ptr<StateSet> _stateset;

};

}

#endif
