#include <c10/core/Contiguity.h>
#include <c10/core/MemoryFormat.h>
#include <c10/core/SymInt.h>
#include <c10/core/SymIntArrayRef.h>
#include <c10/core/SymbolicShapeMeta.h>

namespace c10 {

SymbolicShapeMeta::SymbolicShapeMeta(const SymbolicShapeMeta& other)
    // Non-mutables can be accessed outside the mutex
    : sizes_(other.sizes_),
      strides_(other.strides_),
      storage_offset_(other.storage_offset_),
      strides_valid_(other.strides_valid_) {
  std::scoped_lock lock(other.mutables_);
  // These must be copied under lock, so ignore clang-tidy here!
  // NOLINTBEGIN(cppcoreguidelines-prefer-member-initializer)
  numel_ = other.numel_;
  is_contiguous_ = other.is_contiguous_;
  is_channels_last_contiguous_ = other.is_channels_last_contiguous_;
  is_channels_last_3d_contiguous_ = other.is_channels_last_3d_contiguous_;
  is_channels_last_ = other.is_channels_last_;
  is_channels_last_3d_ = other.is_channels_last_3d_;
  is_non_overlapping_and_dense_ = other.is_non_overlapping_and_dense_;
  available_.store(other.available_.load());
  // NOLINTEND(cppcoreguidelines-prefer-member-initializer)
}

// base, sizes, strides
static std::optional<
    std::tuple<SymNode, std::vector<SymNode>, std::vector<SymNode>>>
normalize_sym_sizes_strides(SymIntArrayRef sizes, SymIntArrayRef strides) {
  // Look for a SymNode to dispatch on
  SymNode base;
  bool all_hinted = true;
  // NB: sizes/strides guaranteed to be positive, so only need
  // is_heap_allocated
  for (const auto& s : sizes) {
    if (all_hinted && !s.has_hint()) {
      all_hinted = false;
    }
    if (!base && s.is_heap_allocated()) {
      base = s.toSymNode();
    }
  }
  for (const auto& s : strides) {
    if (all_hinted && !s.has_hint()) {
      all_hinted = false;
    }
    if (!base && s.is_heap_allocated()) {
      base = s.toSymNode();
    }
  }
  if (!base || all_hinted) {
    // Couldn't find.  Tell the caller to do the normal computation
    // Alternately, if everything is hinted, we want the normal computation
    // too
    return std::nullopt;
  }
  // Populate the SymNode array
  std::vector<SymNode> size_nodes;
  std::vector<SymNode> stride_nodes;
  size_nodes.reserve(sizes.size());
  stride_nodes.reserve(strides.size());
  for (const auto& s : sizes) {
    size_nodes.emplace_back(s.wrap_node(base));
  }
  for (const auto& s : strides) {
    stride_nodes.emplace_back(s.wrap_node(base));
  }
  return std::tuple<SymNode, std::vector<SymNode>, std::vector<SymNode>>(
      std::move(base), std::move(size_nodes), std::move(stride_nodes));
}
namespace {
bool all_hinted(
    const c10::SymIntArrayRef& sizes,
    const c10::SymIntArrayRef& strides) {
  auto all_hinted = true;
  for (const auto& s : sizes) {
    if (!s.has_hint()) {
      return false;
    }
  }

  if (all_hinted) {
    for (const auto& s : strides) {
      if (!s.has_hint()) {
        return false;
      }
    }
  }
  return all_hinted;
}
} // namespace

// Special treatment because of numel
SymBool SymbolicShapeMeta::compute_contiguous() const {
  if (!strides_valid_) {
    return false;
  }
  c10::SymIntArrayRef sizes(sizes_);
  c10::SymIntArrayRef strides(strides_);

  auto result = _compute_contiguous_sym(sizes, strides, numel());

  // If the result is already determined without guarding, just return it.
  auto maybe_as_bool = result.maybe_as_bool();
  if (maybe_as_bool.has_value()) {
    return maybe_as_bool.value();
  }

  if (all_hinted(sizes, strides)) {
    // We avoid going through the slow path if everything is hinted,
    // because evaluating a large SymPy expression can be expensive.
    // TODO exclude backed_size_oblivious from this path.
    return _compute_contiguous<SymInt>(sizes_, strides_, numel());
  }

  return result;
}

SymBool SymbolicShapeMeta::compute_channels_last_contiguous_2d() const {
  if (!strides_valid_) {
    return false;
  }
  c10::SymIntArrayRef sizes(sizes_);
  c10::SymIntArrayRef strides(strides_);

  auto result = _compute_channels_last_contiguous_2d_sym(sizes, strides);

  // If the result is already determined without guarding, just return it.
  auto maybe_as_bool = result.maybe_as_bool();
  if (maybe_as_bool.has_value()) {
    return maybe_as_bool.value();
  }

  if (all_hinted(sizes, strides)) {
    // We avoid going through the slow path if everything is hinted,
    // because evaluating a large SymPy expression can be expensive.
    // TODO exclude backed_size_oblivious from this path.
    return _compute_channels_last_contiguous_2d<SymInt>(sizes_, strides_);
  }

  return result;
}

SymBool SymbolicShapeMeta::compute_channels_last_contiguous_3d() const {
  if (!strides_valid_) {
    return false;
  }
  c10::SymIntArrayRef sizes(sizes_);
  c10::SymIntArrayRef strides(strides_);

  auto result = _compute_channels_last_contiguous_3d_sym(sizes, strides);

  // If the result is already determined without guarding, just return it.
  auto maybe_as_bool = result.maybe_as_bool();
  if (maybe_as_bool.has_value()) {
    return maybe_as_bool.value();
  }

  if (all_hinted(sizes, strides)) {
    // We avoid going through the slow path if everything is hinted,
    // because evaluating a large SymPy expression can be expensive.
    // TODO exclude backed_size_oblivious from this path.
    return _compute_channels_last_contiguous_3d<SymInt>(sizes_, strides_);
  }

  return result;
}

// The rest of them
#define DEFINE_EAGER_SYMBOOL_COMPUTE(name, fallback) \
  SymBool SymbolicShapeMeta::name() const {          \
    if (!strides_valid_) {                           \
      return false;                                  \
    }                                                \
    c10::SymIntArrayRef sizes(sizes_);               \
    c10::SymIntArrayRef strides(strides_);           \
    return fallback(sizes, strides);                 \
  }

#define DEFINE_SYMBOOL_COMPUTE(name, nodeimpl, fallback)        \
  SymBool SymbolicShapeMeta::name() const {                     \
    if (!strides_valid_) {                                      \
      return false;                                             \
    }                                                           \
    auto n = normalize_sym_sizes_strides(sizes_, strides_);     \
    if (n.has_value()) {                                        \
      auto [base, size_nodes, stride_nodes] = *n;               \
      return SymBool(base->nodeimpl(size_nodes, stride_nodes)); \
    } else {                                                    \
      c10::SymIntArrayRef sizes(sizes_);                        \
      c10::SymIntArrayRef strides(strides_);                    \
      return fallback(sizes, strides);                          \
    }                                                           \
  }

// clang-format off
DEFINE_EAGER_SYMBOOL_COMPUTE(compute_strides_like_channels_last_2d, is_channels_last_strides_2d)
DEFINE_EAGER_SYMBOOL_COMPUTE(compute_strides_like_channels_last_3d, is_channels_last_strides_3d)

DEFINE_SYMBOOL_COMPUTE(compute_non_overlapping_and_dense, is_non_overlapping_and_dense, _compute_non_overlapping_and_dense)

// clang-format on

#undef DEFINE_SYMBOOL_COMPUTE

// Glue compute
// NB: this logic very intentionally short circuits if possible.  Without
// short circuiting, it causes
// python test/functorch/test_aotdispatch.py -k
// test_aot_autograd_symbolic_exhaustive_nn_functional_unfold_cpu_float32 to run
// very slowly.

SymBool SymbolicShapeMeta::compute_is_non_overlapping_and_dense_dim4() const {
  init_is_contiguous();
  if (guard_or_false(is_contiguous(), __FILE__, __LINE__)) {
    return true;
  }
  init_is_channels_last_contiguous();
  if (guard_or_false(is_channels_last_contiguous(), __FILE__, __LINE__)) {
    return true;
  }
  return is_contiguous() | is_channels_last_contiguous() |
      compute_non_overlapping_and_dense();
}

SymBool SymbolicShapeMeta::compute_channels_last_contiguous_3d_dim5() const {
  init_is_channels_last_contiguous();
  if (guard_or_false(is_channels_last_contiguous(), __FILE__, __LINE__)) {
    return false;
  }
  return ~is_channels_last_contiguous() & compute_channels_last_contiguous_3d();
}

SymBool SymbolicShapeMeta::compute_channels_last_2d_dim5() const {
  init_is_channels_last_3d_contiguous();
  if (guard_or_false(is_channels_last_3d_contiguous(), __FILE__, __LINE__)) {
    return false;
  }
  return ~is_channels_last_3d_contiguous() &
      compute_strides_like_channels_last_2d();
}

SymBool SymbolicShapeMeta::compute_channels_last_3d_dim5() const {
  if (guard_or_false(is_channels_last(), __FILE__, __LINE__)) {
    return false;
  }
  return ~is_channels_last() & compute_strides_like_channels_last_3d();
}

SymBool SymbolicShapeMeta::compute_is_non_overlapping_and_dense_dim5() const {
  if (guard_or_false(is_contiguous(), __FILE__, __LINE__)) {
    return true;
  }
  if (guard_or_false(is_channels_last_contiguous(), __FILE__, __LINE__)) {
    return true;
  }
  if (guard_or_false(is_channels_last_3d_contiguous(), __FILE__, __LINE__)) {
    return true;
  }
  return is_contiguous() | is_channels_last_contiguous() |
      is_channels_last_3d_contiguous() | compute_non_overlapping_and_dense();
}

SymBool SymbolicShapeMeta::compute_is_non_overlapping_and_dense_anydim() const {
  if (guard_or_false(is_contiguous(), __FILE__, __LINE__)) {
    return true;
  }
  return is_contiguous() | compute_non_overlapping_and_dense();
}

void SymbolicShapeMeta::set_numel(SymInt val) const {
  std::scoped_lock lock(mutables_);
  if (has_numel()) {
    return;
  }
  numel_ = std::move(val);
  available_.fetch_or(numel_avail);
}

void SymbolicShapeMeta::set_is_contiguous(SymBool val) const {
  std::scoped_lock lock(mutables_);
  if (has_is_contiguous()) {
    return;
  }
  is_contiguous_ = std::move(val);
  available_.fetch_or(is_contiguous_avail);
}

void SymbolicShapeMeta::set_is_channels_last_contiguous(SymBool val) const {
  std::scoped_lock lock(mutables_);
  if (has_is_channels_last_contiguous()) {
    return;
  }
  is_channels_last_contiguous_ = std::move(val);
  available_.fetch_or(is_channels_last_contiguous_avail);
}

void SymbolicShapeMeta::set_is_channels_last_3d_contiguous(SymBool val) const {
  std::scoped_lock lock(mutables_);
  if (has_is_channels_last_3d_contiguous()) {
    return;
  }
  is_channels_last_3d_contiguous_ = std::move(val);
  available_.fetch_or(is_channels_last_3d_contiguous_avail);
}

void SymbolicShapeMeta::set_is_channels_last(SymBool val) const {
  std::scoped_lock lock(mutables_);
  if (has_is_channels_last()) {
    return;
  }
  is_channels_last_ = std::move(val);
  available_.fetch_or(is_channels_last_avail);
}

void SymbolicShapeMeta::set_is_channels_last_3d(SymBool val) const {
  std::scoped_lock lock(mutables_);
  if (has_is_channels_last_3d()) {
    return;
  }
  is_channels_last_3d_ = std::move(val);
  available_.fetch_or(is_channels_last_3d_avail);
}

void SymbolicShapeMeta::set_is_non_overlapping_and_dense(SymBool val) const {
  std::scoped_lock lock(mutables_);
  if (has_is_non_overlapping_and_dense()) {
    return;
  }
  is_non_overlapping_and_dense_ = std::move(val);
  available_.fetch_or(is_non_overlapping_and_dense_avail);
}

void SymbolicShapeMeta::init_numel() const {
  set_numel(multiply_integers(sizes_));
}

void SymbolicShapeMeta::init_is_contiguous() const {
  set_is_contiguous(compute_contiguous());
}

void SymbolicShapeMeta::init_is_channels_last_contiguous() const {
  set_is_channels_last_contiguous([&] {
    switch (dim()) {
      case 5:
      case 4: {
        return compute_channels_last_contiguous_2d();
      }
      default:
        return SymBool{false};
    }
  }());
}

void SymbolicShapeMeta::init_is_channels_last_3d_contiguous() const {
  set_is_channels_last_3d_contiguous([&] {
    switch (dim()) {
      case 5:
        return compute_channels_last_contiguous_3d_dim5();
      default:
        return SymBool{false};
    }
  }());
}

void SymbolicShapeMeta::init_is_channels_last() const {
  set_is_channels_last([&] {
    switch (dim()) {
      case 5:
        return compute_channels_last_2d_dim5();
      case 4:
        return compute_strides_like_channels_last_2d();
      default:
        return SymBool{false};
    }
  }());
}

void SymbolicShapeMeta::init_is_channels_last_3d() const {
  set_is_channels_last_3d([&] {
    switch (dim()) {
      case 5:
        return compute_channels_last_3d_dim5();
      default:
        return SymBool{false};
    }
  }());
}

void SymbolicShapeMeta::init_is_non_overlapping_and_dense() const {
  set_is_non_overlapping_and_dense([&] {
    switch (dim()) {
      case 5:
        return compute_is_non_overlapping_and_dense_dim5();
      case 4:
        return compute_is_non_overlapping_and_dense_dim4();
      default:
        return compute_is_non_overlapping_and_dense_anydim();
    }
  }());
}

} // namespace c10