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

#pragma once

#include "../tasking/taskscheduler.h"
#include "../sys/array.h"
#include "../math/math.h"
#include "../math/range.h"

#if defined(TASKING_GCD) && defined(BUILD_IOS)
#include <dispatch/dispatch.h>
#include <algorithm>
#include <type_traits>
#endif

namespace embree
{
  /* parallel_for without range */
  template<typename Index, typename Func>
    __forceinline void parallel_for( const Index N, const Func& func)
  {
#if defined(TASKING_INTERNAL)
    if (N) {
      TaskScheduler::spawn(Index(0),N,Index(1),[&] (const range<Index>& r) {
          assert(r.size() == 1);
          func(r.begin());
        });
      if (!TaskScheduler::wait())
        // -- GODOT start --
        // throw std::runtime_error("task cancelled");
        abort(); 
        // -- GODOT end --
    }
#elif defined(TASKING_GCD) && defined(BUILD_IOS)
      
    const size_t baselineNumBlocks = (TaskScheduler::threadCount() > 1)? TaskScheduler::threadCount() : 1;
    const size_t length = N;
    const size_t blockSize = (length + baselineNumBlocks-1) / baselineNumBlocks;
    const size_t numBlocks = (length + blockSize-1) / blockSize;
      
    dispatch_apply(numBlocks, DISPATCH_APPLY_AUTO, ^(size_t currentBlock) {
          
        const size_t start = (currentBlock * blockSize);
        const size_t blockLength = std::min(length - start, blockSize);
        const size_t end = start + blockLength;
          
        for(size_t i=start; i < end; i++)
        {
            func(i);
        }
    });
      
#elif defined(TASKING_TBB)
  #if TBB_INTERFACE_VERSION >= 12002
    tbb::task_group_context context;
    tbb::parallel_for(Index(0),N,Index(1),[&](Index i) {
        func(i);
      },context);
    if (context.is_group_execution_cancelled())
      // -- GODOT start --
      // throw std::runtime_error("task cancelled");
      abort(); 
      // -- GODOT end --
  #else
    tbb::parallel_for(Index(0),N,Index(1),[&](Index i) {
        func(i);
      });
    if (tbb::task::self().is_cancelled())
      // -- GODOT start --
      // throw std::runtime_error("task cancelled");
      abort(); 
      // -- GODOT end --
  #endif

#elif defined(TASKING_PPL)
    concurrency::parallel_for(Index(0),N,Index(1),[&](Index i) { 
        func(i);
      });
#else
#  error "no tasking system enabled"
#endif
  }
  
  /* parallel for with range and granulatity */
  template<typename Index, typename Func>
    __forceinline void parallel_for( const Index first, const Index last, const Index minStepSize, const Func& func)
  {
    assert(first <= last);
#if defined(TASKING_INTERNAL)
    TaskScheduler::spawn(first,last,minStepSize,func);
    if (!TaskScheduler::wait())
      // -- GODOT start --
      // throw std::runtime_error("task cancelled");
      abort(); 
      // -- GODOT end --

#elif defined(TASKING_GCD) && defined(BUILD_IOS)
      
    const size_t baselineNumBlocks = (TaskScheduler::threadCount() > 1)? 4*TaskScheduler::threadCount() : 1;
    const size_t length = last - first;
    const size_t blockSizeByThreads = (length + baselineNumBlocks-1) / baselineNumBlocks;
    size_t blockSize = std::max<size_t>(minStepSize,blockSizeByThreads);
    blockSize += blockSize % 4;
      
    const size_t numBlocks = (length + blockSize-1) / blockSize;
      
    dispatch_apply(numBlocks, DISPATCH_APPLY_AUTO, ^(size_t currentBlock) {
          
        const size_t start = first + (currentBlock * blockSize);
        const size_t end = std::min<size_t>(last, start + blockSize);
          
        func( embree::range<Index>(start,end) );
    });
      

#elif defined(TASKING_TBB)
  #if TBB_INTERFACE_VERSION >= 12002
    tbb::task_group_context context;
    tbb::parallel_for(tbb::blocked_range<Index>(first,last,minStepSize),[&](const tbb::blocked_range<Index>& r) {
        func(range<Index>(r.begin(),r.end()));
      },context);
    if (context.is_group_execution_cancelled())
      // -- GODOT start --
      // throw std::runtime_error("task cancelled");
      abort(); 
      // -- GODOT end --
  #else
    tbb::parallel_for(tbb::blocked_range<Index>(first,last,minStepSize),[&](const tbb::blocked_range<Index>& r) {
        func(range<Index>(r.begin(),r.end()));
      });
    if (tbb::task::self().is_cancelled())
      // -- GODOT start --
      // throw std::runtime_error("task cancelled");
      abort(); 
      // -- GODOT end --
  #endif

#elif defined(TASKING_PPL)
    concurrency::parallel_for(first, last, Index(1) /*minStepSize*/, [&](Index i) { 
        func(range<Index>(i,i+1)); 
      });

#else
#  error "no tasking system enabled"
#endif
  }
  
  /* parallel for with range */
  template<typename Index, typename Func>
    __forceinline void parallel_for( const Index first, const Index last, const Func& func)
  {
    assert(first <= last);
    parallel_for(first,last,(Index)1,func);
  }

#if defined(TASKING_TBB) && (TBB_INTERFACE_VERSION > 4001)

  template<typename Index, typename Func>
    __forceinline void parallel_for_static( const Index N, const Func& func)
  {
    #if TBB_INTERFACE_VERSION >= 12002
      tbb::task_group_context context;
      tbb::parallel_for(Index(0),N,Index(1),[&](Index i) {
          func(i);
        },tbb::simple_partitioner(),context);
      if (context.is_group_execution_cancelled())
        // -- GODOT start --
        // throw std::runtime_error("task cancelled");
        abort(); 
        // -- GODOT end --
    #else
      tbb::parallel_for(Index(0),N,Index(1),[&](Index i) {
          func(i);
        },tbb::simple_partitioner());
      if (tbb::task::self().is_cancelled())
        // -- GODOT start --
        // throw std::runtime_error("task cancelled");
        abort(); 
        // -- GODOT end --
    #endif
  }

  typedef tbb::affinity_partitioner affinity_partitioner;

  template<typename Index, typename Func>
    __forceinline void parallel_for_affinity( const Index N, const Func& func, tbb::affinity_partitioner& ap)
  {
    #if TBB_INTERFACE_VERSION >= 12002
      tbb::task_group_context context;
      tbb::parallel_for(Index(0),N,Index(1),[&](Index i) {
          func(i);
        },ap,context);
      if (context.is_group_execution_cancelled())
       // -- GODOT start --
       // throw std::runtime_error("task cancelled");
       abort(); 
       // -- GODOT end --
    #else
      tbb::parallel_for(Index(0),N,Index(1),[&](Index i) {
          func(i);
        },ap);
      if (tbb::task::self().is_cancelled())
        // -- GODOT start --
        // throw std::runtime_error("task cancelled");
        abort(); 
        // -- GODOT end --
    #endif
  }

#else

  template<typename Index, typename Func>
    __forceinline void parallel_for_static( const Index N, const Func& func) 
  {
    parallel_for(N,func);
  }

  struct affinity_partitioner {
  };

  template<typename Index, typename Func>
    __forceinline void parallel_for_affinity( const Index N, const Func& func, affinity_partitioner& ap) 
  {
    parallel_for(N,func);
  }

#endif
}