// Copyright 2009-2020 Intel Corporation
// SPDX-License-Identifier: Apache-2.0

#pragma once

#include "../common/default.h"
#include "../common/alloc.h"
#include "../common/accel.h"
#include "../common/device.h"
#include "../common/scene.h"
#include "../geometry/primitive.h"
#include "../common/ray.h"

namespace embree
{
  /* BVH node reference with bounds */
  template<typename NodeRef>
  struct BVHNodeRecord
  {
    __forceinline BVHNodeRecord() {}
    __forceinline BVHNodeRecord(NodeRef ref, const BBox3fa& bounds) : ref(ref), bounds((BBox3fx)bounds) {}
    __forceinline BVHNodeRecord(NodeRef ref, const BBox3fx& bounds) : ref(ref), bounds(bounds) {}

    NodeRef ref;
    BBox3fx bounds;
  };

  template<typename NodeRef>
  struct BVHNodeRecordMB
  {
    __forceinline BVHNodeRecordMB() {}
    __forceinline BVHNodeRecordMB(NodeRef ref, const LBBox3fa& lbounds) : ref(ref), lbounds(lbounds) {}

    NodeRef ref;
    LBBox3fa lbounds;
  };

  template<typename NodeRef>
  struct BVHNodeRecordMB4D
  {
    __forceinline BVHNodeRecordMB4D() {}
    __forceinline BVHNodeRecordMB4D(NodeRef ref, const LBBox3fa& lbounds, const BBox1f& dt) : ref(ref), lbounds(lbounds), dt(dt) {}

    NodeRef ref;
    LBBox3fa lbounds;
    BBox1f dt;
  };

  template<typename NodeRef, int N> struct BaseNode_t;
  template<typename NodeRef, int N> struct AABBNode_t;
  template<typename NodeRef, int N> struct AABBNodeMB_t;
  template<typename NodeRef, int N> struct AABBNodeMB4D_t;
  template<typename NodeRef, int N> struct OBBNode_t;
  template<typename NodeRef, int N> struct OBBNodeMB_t;
  template<typename NodeRef, int N> struct QuantizedNode_t;
  template<typename NodeRef, int N> struct QuantizedNodeMB_t;
  
  /*! Pointer that points to a node or a list of primitives */
  template<int N>
    struct NodeRefPtr
  {
    //template<int NN> friend class BVHN;

    /*! Number of bytes the nodes and primitives are minimally aligned to.*/
    static const size_t byteAlignment = 16;
    static const size_t byteNodeAlignment = 4*N;

    /*! highest address bit is used as barrier for some algorithms */
    static const size_t barrier_mask = (1LL << (8*sizeof(size_t)-1));

    /*! Masks the bits that store the number of items per leaf. */
    static const size_t align_mask = byteAlignment-1;
    static const size_t items_mask = byteAlignment-1;

    /*! different supported node types */
    static const size_t tyAABBNode = 0;
    static const size_t tyAABBNodeMB = 1;
    static const size_t tyAABBNodeMB4D = 6;
    static const size_t tyOBBNode = 2;
    static const size_t tyOBBNodeMB = 3;
    static const size_t tyQuantizedNode = 5;
    static const size_t tyLeaf = 8;

    /*! Empty node */
    static const size_t emptyNode = tyLeaf;

    /*! Invalid node, used as marker in traversal */
    static const size_t invalidNode = (((size_t)-1) & (~items_mask)) | (tyLeaf+0);
    static const size_t popRay      = (((size_t)-1) & (~items_mask)) | (tyLeaf+1);

    /*! Maximum number of primitive blocks in a leaf. */
    static const size_t maxLeafBlocks = items_mask-tyLeaf;
        
    /*! Default constructor */
    __forceinline NodeRefPtr () {}
    
    /*! Construction from integer */
    __forceinline NodeRefPtr (size_t ptr) : ptr(ptr) {}
    
    /*! Cast to size_t */
    __forceinline operator size_t() const { return ptr; }
    
    /*! Sets the barrier bit. */
    __forceinline void setBarrier() {
#if defined(__X86_64__)
      assert(!isBarrier());
      ptr |= barrier_mask;
#else
      assert(false);
#endif
    }
    
    /*! Clears the barrier bit. */
    __forceinline void clearBarrier() {
#if defined(__X86_64__)
      ptr &= ~barrier_mask;
#else
      assert(false);
#endif
    }
    
    /*! Checks if this is an barrier. A barrier tells the top level tree rotations how deep to enter the tree. */
    __forceinline bool isBarrier() const { return (ptr & barrier_mask) != 0; }
    
    /*! checks if this is a leaf */
    __forceinline size_t isLeaf() const { return ptr & tyLeaf; }
    
    /*! returns node type */
    __forceinline int type() const { return ptr & (size_t)align_mask; }
    
    /*! checks if this is a node */
    __forceinline int isAABBNode() const { return (ptr & (size_t)align_mask) == tyAABBNode; }
    
    /*! checks if this is a motion blur node */
    __forceinline int isAABBNodeMB() const { return (ptr & (size_t)align_mask) == tyAABBNodeMB; }
    
    /*! checks if this is a 4D motion blur node */
    __forceinline int isAABBNodeMB4D() const { return (ptr & (size_t)align_mask) == tyAABBNodeMB4D; }
    
    /*! checks if this is a node with unaligned bounding boxes */
    __forceinline int isOBBNode() const { return (ptr & (size_t)align_mask) == tyOBBNode; }
    
    /*! checks if this is a motion blur node with unaligned bounding boxes */
    __forceinline int isOBBNodeMB() const { return (ptr & (size_t)align_mask) == tyOBBNodeMB; }
    
    /*! checks if this is a quantized node */
    __forceinline int isQuantizedNode() const { return (ptr & (size_t)align_mask) == tyQuantizedNode; }

    /*! Encodes a node */
    static __forceinline NodeRefPtr encodeNode(AABBNode_t<NodeRefPtr,N>* node) {
      assert(!((size_t)node & align_mask));
      return NodeRefPtr((size_t) node);
    }

    static __forceinline NodeRefPtr encodeNode(AABBNodeMB_t<NodeRefPtr,N>* node) {
      assert(!((size_t)node & align_mask));
      return NodeRefPtr((size_t) node | tyAABBNodeMB);
    }

    static __forceinline NodeRefPtr encodeNode(AABBNodeMB4D_t<NodeRefPtr,N>* node) {
      assert(!((size_t)node & align_mask));
      return NodeRefPtr((size_t) node | tyAABBNodeMB4D);
    }

    /*! Encodes an unaligned node */
    static __forceinline NodeRefPtr encodeNode(OBBNode_t<NodeRefPtr,N>* node) {
      return NodeRefPtr((size_t) node | tyOBBNode);
    }

    /*! Encodes an unaligned motion blur node */
    static __forceinline NodeRefPtr encodeNode(OBBNodeMB_t<NodeRefPtr,N>* node) {
      return NodeRefPtr((size_t) node | tyOBBNodeMB);
    }

    /*! Encodes a leaf */
    static __forceinline NodeRefPtr encodeLeaf(void* tri, size_t num) {
      assert(!((size_t)tri & align_mask));
      assert(num <= maxLeafBlocks);
      return NodeRefPtr((size_t)tri | (tyLeaf+min(num,(size_t)maxLeafBlocks)));
    }

    /*! Encodes a leaf */
    static __forceinline NodeRefPtr encodeTypedLeaf(void* ptr, size_t ty) {
      assert(!((size_t)ptr & align_mask));
      return NodeRefPtr((size_t)ptr | (tyLeaf+ty));
    }
    
    /*! returns base node pointer */
    __forceinline BaseNode_t<NodeRefPtr,N>* baseNode()
    {
      assert(!isLeaf());
      return (BaseNode_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask);
    }
    __forceinline const BaseNode_t<NodeRefPtr,N>* baseNode() const
    {
      assert(!isLeaf());
      return (const BaseNode_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask);
    }
    
    /*! returns node pointer */
    __forceinline       AABBNode_t<NodeRefPtr,N>* getAABBNode()       { assert(isAABBNode()); return (      AABBNode_t<NodeRefPtr,N>*)ptr; }
    __forceinline const AABBNode_t<NodeRefPtr,N>* getAABBNode() const { assert(isAABBNode()); return (const AABBNode_t<NodeRefPtr,N>*)ptr; }
    
    /*! returns motion blur node pointer */
    __forceinline       AABBNodeMB_t<NodeRefPtr,N>* getAABBNodeMB()       { assert(isAABBNodeMB() || isAABBNodeMB4D()); return (      AABBNodeMB_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    __forceinline const AABBNodeMB_t<NodeRefPtr,N>* getAABBNodeMB() const { assert(isAABBNodeMB() || isAABBNodeMB4D()); return (const AABBNodeMB_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    
    /*! returns 4D motion blur node pointer */
    __forceinline       AABBNodeMB4D_t<NodeRefPtr,N>* getAABBNodeMB4D()       { assert(isAABBNodeMB4D()); return (      AABBNodeMB4D_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    __forceinline const AABBNodeMB4D_t<NodeRefPtr,N>* getAABBNodeMB4D() const { assert(isAABBNodeMB4D()); return (const AABBNodeMB4D_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    
    /*! returns unaligned node pointer */
    __forceinline       OBBNode_t<NodeRefPtr,N>* ungetAABBNode()       { assert(isOBBNode()); return (      OBBNode_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    __forceinline const OBBNode_t<NodeRefPtr,N>* ungetAABBNode() const { assert(isOBBNode()); return (const OBBNode_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    
    /*! returns unaligned motion blur node pointer */
    __forceinline       OBBNodeMB_t<NodeRefPtr,N>* ungetAABBNodeMB()       { assert(isOBBNodeMB()); return (      OBBNodeMB_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    __forceinline const OBBNodeMB_t<NodeRefPtr,N>* ungetAABBNodeMB() const { assert(isOBBNodeMB()); return (const OBBNodeMB_t<NodeRefPtr,N>*)(ptr & ~(size_t)align_mask); }
    
    /*! returns quantized node pointer */
    __forceinline       QuantizedNode_t<NodeRefPtr,N>* quantizedNode()       { assert(isQuantizedNode()); return (      QuantizedNode_t<NodeRefPtr,N>*)(ptr  & ~(size_t)align_mask ); }
    __forceinline const QuantizedNode_t<NodeRefPtr,N>* quantizedNode() const { assert(isQuantizedNode()); return (const QuantizedNode_t<NodeRefPtr,N>*)(ptr  & ~(size_t)align_mask ); }
    
    /*! returns leaf pointer */
    __forceinline char* leaf(size_t& num) const {
      assert(isLeaf());
      num = (ptr & (size_t)items_mask)-tyLeaf;
      return (char*)(ptr & ~(size_t)align_mask);
    }
    
    /*! clear all bit flags */
    __forceinline void clearFlags() {
      ptr &= ~(size_t)align_mask;
    }
    
     /*! returns the wideness */
    __forceinline size_t getN() const { return N; }
    
  public:
    size_t ptr;
  };
}