// ======================================================================== //
// Copyright 2009-2017 Intel Corporation                                    //
//                                                                          //
// Licensed under the Apache License, Version 2.0 (the "License");          //
// you may not use this file except in compliance with the License.         //
// You may obtain a copy of the License at                                  //
//                                                                          //
//     http://www.apache.org/licenses/LICENSE-2.0                           //
//                                                                          //
// Unless required by applicable law or agreed to in writing, software      //
// distributed under the License is distributed on an "AS IS" BASIS,        //
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. //
// See the License for the specific language governing permissions and      //
// limitations under the License.                                           //
// ======================================================================== //

#pragma once

#include "../common/scene.h"
#include "../common/ray.h"

namespace embree
{
  namespace isa
  {
    template<typename Intersector>
      struct ArrayIntersector1
      {
        typedef typename Intersector::Primitive Primitive;
        typedef typename Intersector::Precalculations Precalculations;

        static const bool validIntersectorK = false;

        static __forceinline void intersect(Precalculations& pre, Ray& ray, IntersectContext* context, size_t ty, const Primitive* prim, size_t num, size_t& lazy_node)
        {
          for (size_t i=0; i<num; i++)
            Intersector::intersect(pre,ray,context,prim[i]);
        }
        
        static __forceinline bool occluded(Precalculations& pre, Ray& ray, IntersectContext* context, size_t ty, const Primitive* prim, size_t num, size_t& lazy_node) 
        {
          for (size_t i=0; i<num; i++) {
            if (Intersector::occluded(pre,ray,context,prim[i]))
              return true;
          }
          return false;
        }

        static __forceinline size_t intersect(Precalculations* pre, size_t valid, Ray** rays, IntersectContext* context,  size_t ty, const Primitive* prim, size_t num, size_t& lazy_node)
        {
#if 0
          size_t valid_isec = 0;
          do {
            const size_t i = __bscf(valid);
            const float old_far = rays[i]->tfar;
            for (size_t n=0; n<num; n++)
              Intersector::intersect(pre[i],*rays[i],context,prim[n]);
            valid_isec |= (rays[i]->tfar < old_far) ? ((size_t)1 << i) : 0;            
          } while(unlikely(valid));
          return valid_isec;
#else
          return Intersector::intersect(pre,valid,rays,context,ty,prim,num);
#endif
        }

        static __forceinline size_t occluded(Precalculations* pre, size_t valid, Ray** rays, IntersectContext* context, size_t ty, const Primitive* prim, size_t num, size_t& lazy_node) 
        {
          size_t hit = 0;
          do {
            const size_t i = __bscf(valid);            
            if (occluded(pre[i],*rays[i],context,ty,prim,num,lazy_node))
            {
              hit |= (size_t)1 << i;
              rays[i]->geomID = 0;
            }
          } while(valid);

          return hit;
        }


        template<int K>
        static __forceinline void intersectK(const vbool<K>& valid, /* PrecalculationsK& pre, */ RayK<K>& ray, IntersectContext* context, const Primitive* prim, size_t num, size_t& lazy_node)
        {
        }

        template<int K>        
        static __forceinline vbool<K> occludedK(const vbool<K>& valid, /* PrecalculationsK& pre, */ RayK<K>& ray, IntersectContext* context, const Primitive* prim, size_t num, size_t& lazy_node)
        {
          return valid;
        }
      };

    template<typename Intersector1, typename Intersector2>
      struct Select2Intersector1
      {
        typedef void* Primitive;
        typedef typename Intersector1::Primitive* Primitive1;
        typedef typename Intersector2::Primitive* Primitive2;
        typedef typename Intersector1::Precalculations Precalculations1;
        typedef typename Intersector2::Precalculations Precalculations2;

        struct Precalculations : public Precalculations2
        {
          __forceinline Precalculations (const Ray& ray, const void* ptr, unsigned numTimeSteps)
            : Precalculations2(ray,ptr,numTimeSteps), pre1(ray,ptr,numTimeSteps) {}

          Precalculations1 pre1;
        };
        
        static __forceinline void intersect(Precalculations& pre, Ray& ray, IntersectContext* context, size_t ty, const Primitive* prim_i, size_t num, size_t& lazy_node)
        {
          if (likely(ty == 0)) {
            Primitive1 prim = (Primitive1) prim_i;
            for (size_t i=0; i<num; i++)
              Intersector1::intersect(pre.pre1,ray,context,prim[i]);
          } else {
            Primitive2 prim = (Primitive2) prim_i;
            for (size_t i=0; i<num; i++)
              Intersector2::intersect(pre,ray,context,prim[i]);
          }
        }
        
        static __forceinline bool occluded(Precalculations& pre, Ray& ray, IntersectContext* context, size_t ty, const Primitive* prim_i, size_t num, size_t& lazy_node) 
        {
          if (likely(ty == 0)) {
            Primitive1 prim = (Primitive1) prim_i;
            for (size_t i=0; i<num; i++) {
              if (Intersector1::occluded(pre.pre1,ray,context,prim[i]))
                return true;
            }
          } else {
            Primitive2 prim = (Primitive2) prim_i;
            for (size_t i=0; i<num; i++) {
              if (Intersector2::occluded(pre,ray,context,prim[i]))
                return true;
            }
          }
          return false;
        }
      };
    
    template<int K, typename Intersector>
      struct ArrayIntersectorK_1 
      {
        typedef typename Intersector::Primitive Primitive;
        typedef typename Intersector::Precalculations Precalculations;
        
        static __forceinline void intersect(const vbool<K>& valid, Precalculations& pre, RayK<K>& ray, IntersectContext* context, const Primitive* prim, size_t num, size_t& lazy_node)
        {
          for (size_t i=0; i<num; i++) {
            Intersector::intersect(valid,pre,ray,context,prim[i]);
          }
        }
        
        static __forceinline vbool<K> occluded(const vbool<K>& valid, Precalculations& pre, RayK<K>& ray, IntersectContext* context, const Primitive* prim, size_t num, size_t& lazy_node) 
        {
          vbool<K> valid0 = valid;
          for (size_t i=0; i<num; i++) {
            valid0 &= !Intersector::occluded(valid0,pre,ray,context,prim[i]);
            if (none(valid0)) break;
          }
          return !valid0;
        }
        
        static __forceinline void intersect(Precalculations& pre, RayK<K>& ray, size_t k, IntersectContext* context, const Primitive* prim, size_t num, size_t& lazy_node)
        {
          for (size_t i=0; i<num; i++) {
            Intersector::intersect(pre,ray,k,context,prim[i]);
          }
        }
        
        static __forceinline bool occluded(Precalculations& pre, RayK<K>& ray, size_t k, IntersectContext* context, const Primitive* prim, size_t num, size_t& lazy_node) 
        {
          for (size_t i=0; i<num; i++) {
            if (Intersector::occluded(pre,ray,k,context,prim[i]))
              return true;
          }
          return false;
        }
      };

    // =============================================================================================

    template<int K, typename Intersector1, typename IntersectorK>
      struct ArrayIntersectorKStream 
      {
        typedef typename Intersector1::Primitive Primitive;
        typedef typename Intersector1::Precalculations Precalculations;
        typedef typename IntersectorK::Primitive PrimitiveK;
        typedef typename IntersectorK::Precalculations PrecalculationsK;

        static const bool validIntersectorK = true;
        
        static __forceinline void intersectK(const vbool<K>& valid, /* PrecalculationsK& pre, */ RayK<K>& ray, IntersectContext* context, const PrimitiveK* prim, size_t num, size_t& lazy_node)
        {
          PrecalculationsK pre(valid,ray,1); //todo: might cause trouble

          for (size_t i=0; i<num; i++) {
            IntersectorK::intersect(valid,pre,ray,context,prim[i]);
          }
        }
        
        static __forceinline vbool<K> occludedK(const vbool<K>& valid, /* PrecalculationsK& pre, */ RayK<K>& ray, IntersectContext* context, const PrimitiveK* prim, size_t num, size_t& lazy_node)
        {
          PrecalculationsK pre(valid,ray,1); //todo: might cause trouble
          vbool<K> valid0 = valid;
          for (size_t i=0; i<num; i++) {
            valid0 &= !IntersectorK::occluded(valid0,pre,ray,context,prim[i]);
            if (none(valid0)) break;
          }
          return !valid0;
        }

        static __forceinline void intersect(Precalculations& pre, Ray& ray, IntersectContext* context, size_t ty, const Primitive* prim, size_t num, size_t& lazy_node)
        {
          for (size_t i=0; i<num; i++)
            Intersector1::intersect(pre,ray,context,prim[i]);
        }
        
        static __forceinline bool occluded(Precalculations& pre, Ray& ray, IntersectContext* context, size_t ty, const Primitive* prim, size_t num, size_t& lazy_node) 
        {
          for (size_t i=0; i<num; i++) {
            if (Intersector1::occluded(pre,ray,context,prim[i]))
              return true;
          }
          return false;
        }

        static __forceinline size_t intersect(Precalculations* pre, size_t valid, Ray** rays, IntersectContext* context,  size_t ty, const Primitive* prim, size_t num, size_t& lazy_node)
        {
          return Intersector1::intersect(pre,valid,rays,context,ty,prim,num);
        }

        static __forceinline size_t occluded(Precalculations* pre, size_t valid, Ray** rays, IntersectContext* context, size_t ty, const Primitive* prim, size_t num, size_t& lazy_node) 
        {
          //todo : fix
          size_t hit = 0;
          do {
            const size_t i = __bscf(valid);            
            if (occluded(pre[i],*rays[i],context,ty,prim,num,lazy_node))
            {
              hit |= (size_t)1 << i;
              rays[i]->geomID = 0;
            }
          } while(valid);

          return hit;
        }
      };
  }
}