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//                        Kokkos v. 2.0
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#ifndef KOKKOS_UNORDERED_MAP_IMPL_HPP
#define KOKKOS_UNORDERED_MAP_IMPL_HPP

#include <Kokkos_Core_fwd.hpp>
#include <stdint.h>

#include <cstdio>
#include <climits>
#include <iostream>
#include <iomanip>

namespace Kokkos { namespace Impl {

uint32_t find_hash_size( uint32_t size );

template <typename Map>
struct UnorderedMapRehash
{
  typedef Map map_type;
  typedef typename map_type::const_map_type const_map_type;
  typedef typename map_type::execution_space execution_space;
  typedef typename map_type::size_type size_type;

  map_type       m_dst;
  const_map_type m_src;

  UnorderedMapRehash( map_type const& dst, const_map_type const& src)
    : m_dst(dst), m_src(src)
  {}

  void apply() const
  {
    parallel_for(m_src.capacity(), *this);
  }

  KOKKOS_INLINE_FUNCTION
  void operator()(size_type i) const
  {
    if ( m_src.valid_at(i) )
      m_dst.insert(m_src.key_at(i), m_src.value_at(i));
  }

};

template <typename UMap>
struct UnorderedMapErase
{
  typedef UMap map_type;
  typedef typename map_type::execution_space execution_space;
  typedef typename map_type::size_type size_type;
  typedef typename map_type::key_type key_type;
  typedef typename map_type::impl_value_type value_type;

  map_type m_map;

  UnorderedMapErase( map_type const& map)
    : m_map(map)
  {}

  void apply() const
  {
    parallel_for(m_map.m_hash_lists.dimension_0(), *this);
  }

  KOKKOS_INLINE_FUNCTION
  void operator()( size_type i ) const
  {
    const size_type invalid_index = map_type::invalid_index;

    size_type curr = m_map.m_hash_lists(i);
    size_type next = invalid_index;

    // remove erased head of the linked-list
    while (curr != invalid_index && !m_map.valid_at(curr)) {
      next = m_map.m_next_index[curr];
      m_map.m_next_index[curr] = invalid_index;
      m_map.m_keys[curr] = key_type();
      if (m_map.is_set) m_map.m_values[curr] = value_type();
      curr = next;
      m_map.m_hash_lists(i) = next;
    }

    // if the list is non-empty and the head is valid
    if (curr != invalid_index && m_map.valid_at(curr) ) {
      size_type prev = curr;
      curr = m_map.m_next_index[prev];

      while (curr != invalid_index) {
        next = m_map.m_next_index[curr];
        if (m_map.valid_at(curr)) {
          prev = curr;
        }
        else {
          // remove curr from list
          m_map.m_next_index[prev] = next;
          m_map.m_next_index[curr] = invalid_index;
          m_map.m_keys[curr] = key_type();
          if (map_type::is_set) m_map.m_values[curr] = value_type();
        }
        curr = next;
      }
    }
  }
};

template <typename UMap>
struct UnorderedMapHistogram
{
  typedef UMap map_type;
  typedef typename map_type::execution_space execution_space;
  typedef typename map_type::size_type size_type;

  typedef View<int[100], execution_space> histogram_view;
  typedef typename histogram_view::HostMirror host_histogram_view;

  map_type m_map;
  histogram_view m_length;
  histogram_view m_distance;
  histogram_view m_block_distance;

  UnorderedMapHistogram( map_type const& map)
    : m_map(map)
    , m_length("UnorderedMap Histogram")
    , m_distance("UnorderedMap Histogram")
    , m_block_distance("UnorderedMap Histogram")
  {}

  void calculate()
  {
    parallel_for(m_map.m_hash_lists.dimension_0(), *this);
  }

  void clear()
  {
    Kokkos::deep_copy(m_length, 0);
    Kokkos::deep_copy(m_distance, 0);
    Kokkos::deep_copy(m_block_distance, 0);
  }

  void print_length(std::ostream &out)
  {
    host_histogram_view host_copy = create_mirror_view(m_length);
    Kokkos::deep_copy(host_copy, m_length);

    for (int i=0, size = host_copy.dimension_0(); i<size; ++i)
    {
      out << host_copy[i] << " , ";
    }
    out << "\b\b\b   " << std::endl;
  }

  void print_distance(std::ostream &out)
  {
    host_histogram_view host_copy = create_mirror_view(m_distance);
    Kokkos::deep_copy(host_copy, m_distance);

    for (int i=0, size = host_copy.dimension_0(); i<size; ++i)
    {
      out << host_copy[i] << " , ";
    }
    out << "\b\b\b   " << std::endl;
  }

  void print_block_distance(std::ostream &out)
  {
    host_histogram_view host_copy = create_mirror_view(m_block_distance);
    Kokkos::deep_copy(host_copy, m_block_distance);

    for (int i=0, size = host_copy.dimension_0(); i<size; ++i)
    {
      out << host_copy[i] << " , ";
    }
    out << "\b\b\b   " << std::endl;
  }

  KOKKOS_INLINE_FUNCTION
  void operator()( size_type i ) const
  {
    const size_type invalid_index = map_type::invalid_index;

    uint32_t length = 0;
    size_type min_index = ~0u, max_index = 0;
    for (size_type curr = m_map.m_hash_lists(i); curr != invalid_index; curr = m_map.m_next_index[curr]) {
      ++length;
      min_index = (curr < min_index) ? curr : min_index;
      max_index = (max_index < curr) ? curr : max_index;
    }

    size_type distance = (0u < length) ? max_index - min_index : 0u;
    size_type blocks = (0u < length) ? max_index/32u - min_index/32u : 0u;

    // normalize data
    length   = length   < 100u ? length   : 99u;
    distance = distance < 100u ? distance : 99u;
    blocks   = blocks   < 100u ? blocks   : 99u;

    if (0u < length)
    {
      atomic_fetch_add( &m_length(length), 1);
      atomic_fetch_add( &m_distance(distance), 1);
      atomic_fetch_add( &m_block_distance(blocks), 1);
    }
  }
};

template <typename UMap>
struct UnorderedMapPrint
{
  typedef UMap map_type;
  typedef typename map_type::execution_space execution_space;
  typedef typename map_type::size_type size_type;

  map_type m_map;

  UnorderedMapPrint( map_type const& map)
    : m_map(map)
  {}

  void apply()
  {
    parallel_for(m_map.m_hash_lists.dimension_0(), *this);
  }

  KOKKOS_INLINE_FUNCTION
  void operator()( size_type i ) const
  {
    const size_type invalid_index = map_type::invalid_index;

    uint32_t list = m_map.m_hash_lists(i);
    for (size_type curr = list, ii=0; curr != invalid_index; curr = m_map.m_next_index[curr], ++ii) {
      printf("%d[%d]: %d->%d\n", list, ii, m_map.key_at(curr), m_map.value_at(curr));
    }
  }
};

template <typename DKey, typename DValue, typename SKey, typename SValue>
struct UnorderedMapCanAssign : public false_ {};

template <typename Key, typename Value>
struct UnorderedMapCanAssign<Key,Value,Key,Value> : public true_ {};

template <typename Key, typename Value>
struct UnorderedMapCanAssign<const Key,Value,Key,Value> : public true_ {};

template <typename Key, typename Value>
struct UnorderedMapCanAssign<const Key,const Value,Key,Value> : public true_ {};

template <typename Key, typename Value>
struct UnorderedMapCanAssign<const Key,const Value,const Key,Value> : public true_ {};


}} //Kokkos::Impl

#endif // KOKKOS_UNORDERED_MAP_IMPL_HPP