#include <torch/csrc/autograd/symbolic.h>
#include <torch/csrc/jit/serialization/export.h>
#include <torch/csrc/onnx/onnx.h>

#include <ATen/core/functional.h>
#include <c10/util/Exception.h>
#include <torch/csrc/jit/serialization/import_export_helpers.h>
#include <torch/csrc/jit/passes/dead_code_elimination.h>
#include <torch/csrc/jit/runtime/instruction.h>

#include <onnx/checker.h>
#include <onnx/onnx_pb.h>
#include <onnx/proto_utils.h>

#include <ATen/ATen.h>
#include <c10/util/Optional.h>

#include <fstream>
#include <memory>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <regex>
namespace torch {
namespace jit {

void writeArchiveAndTensors(
    const std::string& archive_name,
    const char* data,
    size_t size,
    const std::vector<WriteableTensorData>& tensors,
    caffe2::serialize::PyTorchStreamWriter& out) {
  std::string prefix = archive_name + "/";
  size_t i = 0;
  for (const auto& td : tensors) {
    std::string fname = prefix + std::to_string(i++);
    out.writeRecord(fname, td.data(), td.sizeInBytes());
  }
  std::string fname = archive_name + ".pkl";
  out.writeRecord(fname, data, size);
}

namespace {
namespace onnx_torch = ::torch::onnx;
namespace onnx = ::ONNX_NAMESPACE;

std::string getNodeStackTraceString(const Node* n) {
  return n->sourceRange().str();
}

void validateBlock(
    Block* b,
    onnx_torch::OperatorExportTypes operator_export_type) {
  for (auto node : b->nodes()) {
    for (Block* sub_block : node->blocks()) {
      validateBlock(sub_block, operator_export_type);
    }
    // Macro'ed so we get a marginally better line number on failed export
#define FAIL_EXPORT(name)                          \
  throw std::runtime_error(                        \
      std::string("ONNX export failed: ") + name + \
      "\n\nGraph we tried to export:\n" + b->owningGraph()->toString());
    if (node->kind() == prim::PythonOp) {
      auto py_node = static_cast<PythonOp*>(node);
      FAIL_EXPORT(
          "Couldn't export Python operator " + py_node->name() +
          "\n\nDefined at:\n" + getNodeStackTraceString(node))
    } else {
      // Special error messages for certain types of operators
      if (node->kind() == aten::expand) {
        if (operator_export_type ==
            onnx_torch::OperatorExportTypes::ONNX_ATEN_FALLBACK) {
          WithInsertPoint guard(node);
          auto* new_node =
              b->owningGraph()->insertNode(b->owningGraph()->create(
                  Symbol(::c10::onnx::ATen),
                  node->inputs(),
                  node->outputs().size()));
          for (size_t i = 0; i < node->outputs().size(); ++i) {
            node->output(i)->replaceAllUsesWith(new_node->output(i));
          }
          new_node->s_(Symbol::fromQualString("attr::operator"), "expand");
        }
      }
      if (node->kind() == prim::PackPadded || node->kind() == prim::PadPacked) {
        FAIL_EXPORT(
            "Cannot export individual pack_padded_sequence or pad_packed_sequence; these operations must occur in pairs.\n\nUsage of this operation occurred at:\n" +
            getNodeStackTraceString(node));
      }
      bool is_aten_enabled = operator_export_type ==
              onnx_torch::OperatorExportTypes::ONNX_ATEN_FALLBACK ||
          operator_export_type == onnx_torch::OperatorExportTypes::ONNX_ATEN;
      if (node->kind().is_aten() && !is_aten_enabled && !node->mustBeNone()) {
        FAIL_EXPORT(
            "Couldn't export operator " + node->kind().toDisplayString() +
            "\n\nDefined at:\n" + getNodeStackTraceString(node));
      }
    }
#undef FAIL_EXPORT
  }
}

void validateGraph(
    const std::shared_ptr<Graph>& graph,
    onnx_torch::OperatorExportTypes operator_export_type) {
  validateBlock(graph->block(), operator_export_type);
  // this is run on an onnx graph which doesn't have side effects.
  // ignore side effects in dead code elimination.
  EliminateDeadCode(graph->block(), true, DCESideEffectPolicy::ALLOW_DELETING_NODES_WITH_SIDE_EFFECTS);
}

std::string GetFileRootPath(const std::string& rootPath) {
    std::string rootPath_ = rootPath;
    // First, making slash consistent.
    std::replace(rootPath_.begin(), rootPath_.end(), '\\', '/');
    // Second, remove trailing slashes, if any
    std::regex trailer("/+$");
    std::string root = std::regex_replace(rootPath_, trailer, std::string());
    std::string folder = root.substr(0, root.find_last_of('/'));
    if (folder == rootPath_) { // If no root folder specified, select cwd.
      return std::string(".");
    }
    return folder;
}

std::string GetExternalFileName(const c10::optional<std::string> external_ref) {
  auto tensorName = external_ref.value();
  const std::string illegalChars = "\\/:?\"<>|";
  for (int i = 0; i < tensorName.size(); i++) {
    if (illegalChars.find(tensorName[i]) != std::string::npos) {
        tensorName[i] = '_';
    }
  }
  return tensorName;
}

void CloseFile(FILE* fp) { 
  fclose(fp);
}

void CreateExternalFile(const at::Tensor& tensor, const std::string& tensorName,
                        const std::string& onnx_file_path) {
  auto folder = GetFileRootPath(onnx_file_path);
  std::string fullFilePath = folder + "/" + tensorName;
  std::unique_ptr<FILE, decltype(&CloseFile)> fp(fopen(fullFilePath.c_str(), "wb"),
                                                 &CloseFile);
  if (fp == NULL) {
    throw std::runtime_error(std::string("ONNX export failed. Could not open file or directory: ") + fullFilePath);
  }
  fwrite(tensor.data_ptr(), tensor.element_size(), tensor.numel(), fp.get());
} // fclose() called here through CloseFile(), if FILE* is not a null pointer.

class EncoderBase {
 public:
  EncoderBase(
      onnx_torch::OperatorExportTypes operator_export_type,
      bool strip_doc);

  onnx::ModelProto get_model_proto() {
    return model_proto_;
  }

 protected:
  // Using std::map instead of std::unordered_map for initializers
  // in EncodeGraph constructor so that the order in which initializers
  // get written to the ONNX graph is always the deterministic and
  // predictable. While this is not a ONNX requirement, it is needed
  // for testing purposes in tests that use _export_to_pretty_string()
  // for validating ONNX graphs.
  void EncodeGraph(
      onnx::GraphProto* graph_proto,
      const std::shared_ptr<Graph>& graph,
      const std::map<std::string, at::Tensor>& initializers =
        std::map<std::string, at::Tensor>(),
      const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes =
        std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>(),
      bool keep_initializers_as_inputs = true,
      bool add_node_names = true,
      bool use_external_data_format = false,
      const std::string& onnx_file_path = std::string());

  void EncodeBlock(
      onnx::GraphProto* graph_proto,
      const Block* block,
      const std::map<std::string, at::Tensor>& initializers =
        std::map<std::string, at::Tensor>(),
      const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes =
        std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>(),
      bool keep_initializers_as_inputs = true,
      bool add_node_names = true,
      bool use_external_data_format = false,
      const std::string& onnx_file_path = std::string());

  virtual void EncodeTensor(
      onnx::TensorProto* tensor_proto,
      const at::Tensor& tensor,
      const c10::optional<std::string> external_ref = {},
      const bool use_external_data_format = false,
      const std::string& onnx_file_path = std::string()) = 0;

  virtual void EncodeIntermediateValueInfo(
      onnx::GraphProto* graph_proto,
      const Value* n){}

  virtual void EncodeValueInfo(
      onnx::GraphProto* graph_proto,
      onnx::ValueInfoProto* v,
      const Value* n,
      const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes =
        std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>());

  void AddAttribute(
      onnx::NodeProto* node_proto,
      const jit::Node* node,
      const jit::Symbol name);

  onnx::ModelProto model_proto_;
  size_t num_blocks_;
  size_t num_op_nodes_;
  onnx_torch::OperatorExportTypes operator_export_type_;
  bool strip_doc_;
  std::set<std::string> domains_;

  // For large models, the parameters can be stored in separate binary files.
  // This parameter sets a threshold on the number of elements in the parameter
  // tensor, beyond which the parameter is stored in a separate file (if API
  // argument use_external_data_format is set to True). This threshold is in place
  // so as not to create too many external files. 
  const size_t ParamSizeThresholdForExternalStorage = 1024;
};

onnx::TensorProto_DataType ATenTypeToOnnxType(at::ScalarType at_type) {
  switch (at_type) {
    case at::kDouble:
      return onnx::TensorProto_DataType_DOUBLE;
    case at::kFloat:
      return onnx::TensorProto_DataType_FLOAT;
    case at::kHalf:
      return onnx::TensorProto_DataType_FLOAT16;
    case at::kByte:
      return onnx::TensorProto_DataType_UINT8;
    case at::kChar:
      return onnx::TensorProto_DataType_INT8;
    case at::kShort:
      return onnx::TensorProto_DataType_INT16;
    case at::kInt:
      return onnx::TensorProto_DataType_INT32;
    case at::kLong:
      return onnx::TensorProto_DataType_INT64;
    case at::kBool:
      return onnx::TensorProto_DataType_BOOL;
    case at::kQInt8:
      return onnx::TensorProto_DataType_INT8;
    case at::kQUInt8:
      return onnx::TensorProto_DataType_UINT8;
    case at::kQInt32:
      return onnx::TensorProto_DataType_INT32;
    default:
      AT_ERROR("unexpected tensor scalar type");
  }
}

EncoderBase::EncoderBase(
    onnx_torch::OperatorExportTypes operator_export_type,
    bool strip_doc)
    : num_blocks_(0),
      num_op_nodes_(0),
      operator_export_type_(operator_export_type),
      strip_doc_(strip_doc) {
  model_proto_.set_producer_name("pytorch");
  // we pin IR version to version 6 (12/11/2019) instead of using
  // onnx::IR_VERSION. with this change, the test_operators.py will be more
  // stable. only bump it when it's necessary
  model_proto_.set_ir_version(onnx_torch::IR_VERSION);
  // TODO: set the producer version using appropriate function call
  model_proto_.set_producer_version(onnx_torch::PRODUCER_VERSION);
}

void EncoderBase::EncodeValueInfo(
    onnx::GraphProto* graph_proto,
    onnx::ValueInfoProto* v,
    const Value* n,
    const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes) {
  std::string name = n->debugName();
  v->set_name(name);
  if (TensorTypePtr node_type = n->type()->cast<TensorType>()) {
    if (!node_type->isComplete()) {
      return;
    }
    onnx::TypeProto* t = v->mutable_type();
    onnx::TypeProto_Tensor* tensor_type = t->mutable_tensor_type();
    onnx::TensorShapeProto* shape = tensor_type->mutable_shape();
    std::vector<std::int64_t> sizes =
        node_type->sizes().concrete_sizes().value();
    for (size_t i = 0; i < sizes.size(); i++) {
      shape->add_dim();
      if ((dynamic_axes.find(name) != dynamic_axes.end()) &&
          (dynamic_axes.at(name).find(i) != dynamic_axes.at(name).end())){
        shape->mutable_dim(i)->set_dim_param(dynamic_axes.at(name).at(i));
      }
      else{
        shape->mutable_dim(i)->set_dim_value(sizes[i]);
      }
    }
    tensor_type->set_elem_type(
        ATenTypeToOnnxType(node_type->scalarType().value()));
  } else if (BoolTypePtr node_type = n->type()->cast<BoolType>()) {
    onnx::TypeProto* t = v->mutable_type();
    onnx::TypeProto_Tensor* tensor_type = t->mutable_tensor_type();
    tensor_type->set_elem_type(ATenTypeToOnnxType(at::kBool));
  }
}

void EncoderBase::EncodeGraph(
    onnx::GraphProto* graph_proto,
    const std::shared_ptr<Graph>& graph,
    const std::map<std::string, at::Tensor>& initializers,
    const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes,
    bool keep_initializers_as_inputs,
    bool add_node_names,
    bool use_external_data_format,
    const std::string& onnx_file_path) {
  EncodeBlock(graph_proto, graph->block(), initializers, dynamic_axes,
              keep_initializers_as_inputs, add_node_names, use_external_data_format,
              onnx_file_path);
}

void EncoderBase::EncodeBlock(
    onnx::GraphProto* graph_proto,
    const Block* block,
    const std::map<std::string, at::Tensor>& initializers,
    const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes,
    bool keep_initializers_as_inputs,
    bool add_node_names,
    bool use_external_data_format,
    const std::string& onnx_file_path) {
  AT_ASSERT(graph_proto != nullptr);
  std::string block_name = "torch-jit-export";
  if (num_blocks_) {
    block_name += std::to_string(num_blocks_);
  }
  num_blocks_++;
  graph_proto->set_name(block_name);

  // Since ONNX IR VERSION 4, initializers do not have to
  // be a subset of graph inputs. We use keep_initializers_as_inputs
  // argument to determine whether to add initializers
  // as inputs or not. If keep_initializers_as_inputs=false,
  // we only add non-parameter inputs as inputs to ONNX graph, and.
  // not the initializers (parameters). If keep_initializers_as_inputs
  // =true, we add initializers as inputs too. Setting
  // keep_initializers_as_inputs=false allows better
  // optimizations, such as constant-folding, on ONNX graphs
  // by backends/optimizers.
  if (keep_initializers_as_inputs) {
    for (auto input : block->inputs()) {
      onnx::ValueInfoProto* v = graph_proto->add_input();
      EncodeValueInfo(graph_proto, v, input, dynamic_axes);
    }
  }
  else {
    for (auto input : block->inputs()) {
      auto it = initializers.find(input->debugName());
      if (it == initializers.end()) {
        onnx::ValueInfoProto* v = graph_proto->add_input();
        EncodeValueInfo(graph_proto, v, input, dynamic_axes);
      }
    }
  }
  for (auto output : block->outputs()) {
    onnx::ValueInfoProto* v = graph_proto->add_output();
    EncodeValueInfo(graph_proto, v, output, dynamic_axes);
  }
  for (auto node : block->nodes()) {
    bool is_raw_export =
        operator_export_type_ == onnx_torch::OperatorExportTypes::RAW;
    if (node->mustBeNone() && !is_raw_export) {
      // None nodes are used to implement optional inputs. One
      // way to "not provide" an optional input is to create an
      // Undefined node, and pass its output as that input.
      continue;
    }
    auto p_n = graph_proto->add_node();
    if (!strip_doc_) {
      p_n->set_doc_string(node->sourceRange().str());
    }
    for (auto input : node->inputs()) {
      if (input->node()->mustBeNone() && !is_raw_export) {
        p_n->add_input("");
      } else {
        p_n->add_input(input->debugName());
      }
    }
    for (auto output : node->outputs()) {
      p_n->add_output(output->debugName());
      EncodeIntermediateValueInfo(graph_proto, output);
    }
    if (!node->kind().is_onnx()) {
      std::string domain;
      if (node->kind().is_aten() || node->kind().is_caffe2()) {
        domain = node->kind().domainString();
      }
      else {  //  Custom namespace and domain
        domain = node->kind().ns().toUnqualString();
      }
      domains_.insert(domain);
      p_n->set_domain(domain);
    }
    if (is_raw_export) {
      AT_ASSERT(!node->kind().is_onnx());
    } else if (operator_export_type_ == onnx_torch::OperatorExportTypes::ONNX) {
      AT_ASSERT(
          !node->kind().is_aten() && !node->kind().is_prim() &&
          !node->kind().is_attr());
    }
    p_n->set_op_type(node->kind().toUnqualString());
    if (add_node_names) {
      p_n->set_name(p_n->op_type() + "_" + std::to_string(num_op_nodes_));
      num_op_nodes_++;
    }
    for (auto attr_name : node->attributeNames()) {
      AddAttribute(p_n, node, attr_name);
    }
    if (is_raw_export && node->blocks().size() > 0) {
      auto blocks = p_n->add_attribute();
      blocks->set_name("_blocks");
      blocks->set_type(onnx::AttributeProto_AttributeType_GRAPHS);
      for (auto block : node->blocks()) {
        auto graph = blocks->add_graphs();
        EncodeBlock(graph, block, initializers);
      }
    }
    if (node->kind() == ::c10::onnx::Loop) {
      AT_ASSERT(node->blocks().size() == 1);

      auto body = p_n->add_attribute();
      body->set_name("body");
      body->set_type(onnx::AttributeProto_AttributeType_GRAPH);
      auto g = body->mutable_g();
      EncodeBlock(g, node->blocks()[0]);
    }
    if (node->kind() == ::c10::onnx::If) {
      AT_ASSERT(node->blocks().size() == 2);

      auto true_branch = p_n->add_attribute();
      true_branch->set_name("then_branch");
      true_branch->set_type(onnx::AttributeProto_AttributeType_GRAPH);
      auto true_g = true_branch->mutable_g();
      EncodeBlock(true_g, node->blocks()[0]);

      auto false_branch = p_n->add_attribute();
      false_branch->set_name("else_branch");
      false_branch->set_type(onnx::AttributeProto_AttributeType_GRAPH);
      auto false_g = false_branch->mutable_g();
      EncodeBlock(false_g, node->blocks()[1]);
    }
  }
  AT_ASSERT(block->inputs().size() >= initializers.size());
  for (auto& name_tensor_pair : initializers) {
    auto p = graph_proto->add_initializer();
    p->set_name(name_tensor_pair.first);
    EncodeTensor(p, name_tensor_pair.second, name_tensor_pair.first,
                 use_external_data_format, onnx_file_path);
  }
}

void EncoderBase::AddAttribute(
    onnx::NodeProto* node_proto,
    const jit::Node* node,
    const jit::Symbol name) {
  auto attr = node_proto->add_attribute();
  AT_ASSERT(name.is_attr());
  attr->set_name(name.toUnqualString());
  switch (node->kindOf(name)) {
    case AttributeKind::f:
      attr->set_f(node->f(name));
      attr->set_type(onnx::AttributeProto_AttributeType_FLOAT);
      break;
    case AttributeKind::fs:
      attr->set_type(onnx::AttributeProto_AttributeType_FLOATS);
      for (auto& v : node->fs(name))
        attr->add_floats(v);
      break;
    case AttributeKind::i:
      attr->set_type(onnx::AttributeProto_AttributeType_INT);
      attr->set_i(node->i(name));
      break;
    case AttributeKind::is:
      attr->set_type(onnx::AttributeProto_AttributeType_INTS);
      for (auto& v : node->is(name))
        attr->add_ints(v);
      break;
    case AttributeKind::s:
      attr->set_type(onnx::AttributeProto_AttributeType_STRING);
      attr->set_s(node->s(name));
      break;
    case AttributeKind::ss:
      attr->set_type(onnx::AttributeProto_AttributeType_STRINGS);
      for (auto& v : node->ss(name))
        attr->add_strings(v);
      break;
    case AttributeKind::t: {
      attr->set_type(onnx::AttributeProto_AttributeType_TENSOR);
      auto t = attr->mutable_t();
      EncodeTensor(t, node->t(name));
    } break;
    case AttributeKind::ts:
      attr->set_type(onnx::AttributeProto_AttributeType_TENSORS);
      for (auto& v : node->ts(name)) {
        auto t = attr->add_tensors();
        EncodeTensor(t, v);
      }
      break;
    case AttributeKind::g: {
      attr->set_type(onnx::AttributeProto_AttributeType_GRAPH);
      auto g = attr->mutable_g();
      EncodeGraph(g, node->g(name));
    } break;
    case AttributeKind::gs:
      attr->set_type(onnx::AttributeProto_AttributeType_GRAPHS);
      for (auto& v : node->gs(name)) {
        auto g = attr->add_graphs();
        EncodeGraph(g, v);
      }
      break;
    default:
      throw std::runtime_error("unexpected attribute kind");
  }
}

class GraphEncoder : public EncoderBase {
 public:
  GraphEncoder(
      const std::shared_ptr<Graph>& graph,
      int64_t onnx_opset_version,
      onnx_torch::OperatorExportTypes operator_export_type,
      const std::map<std::string, at::Tensor>& initializers,
      const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes,
      bool defer_weight_export,
      bool strip_doc,
      bool keep_initializers_as_inputs,
      const std::map<std::string, int>& custom_opsets,
      bool add_node_names,
      bool use_external_data_format,
      const std::string& onnx_file_path);

  RawDataExportMap get_raw_data_export_map() {
    return raw_data_export_map_;
  }

 private:
  void EncodeTensor(
      onnx::TensorProto* tensor_proto,
      const at::Tensor& tensor,
      const c10::optional<std::string> external_ref = {},
      const bool use_external_data_format = false,
      const std::string& onnx_file_path = std::string()) override;

  RawDataExportMap raw_data_export_map_;
  bool defer_weight_export_;
};

GraphEncoder::GraphEncoder(
    const std::shared_ptr<Graph>& graph,
    int64_t onnx_opset_version,
    onnx_torch::OperatorExportTypes operator_export_type,
    const std::map<std::string, at::Tensor>& initializers,
    const std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>& dynamic_axes,
    bool defer_weight_export,
    bool strip_doc,
    bool keep_initializers_as_inputs,
    const std::map<std::string, int>& custom_opsets,
    bool add_node_names,
    bool use_external_data_format,
    const std::string& onnx_file_path)
    : EncoderBase(operator_export_type, strip_doc),
      defer_weight_export_(defer_weight_export) {
  if (operator_export_type != onnx_torch::OperatorExportTypes::RAW) {
    validateGraph(graph, operator_export_type);
  }

  auto* imp = model_proto_.add_opset_import();
  // This is the version of ONNX operator set we are targeting
  imp->set_version(onnx_opset_version);

  EncodeGraph(model_proto_.mutable_graph(), graph, initializers, dynamic_axes,
              keep_initializers_as_inputs, add_node_names, use_external_data_format,
              onnx_file_path);

  for (const std::string& domain : domains_) {
    auto* opset = model_proto_.add_opset_import();
    opset->set_domain(domain);
    //  Check if domain version is registered. If not, set to version 1
    auto it = custom_opsets.find(domain);
    if (it == custom_opsets.end())
      opset->set_version(1);
    else {
      opset->set_version(it->second);
    }
  }

  for (auto const& custom_opset : custom_opsets){
    if (!std::count(domains_.begin(), domains_.end(), custom_opset.first)) {
      AT_WARN("Custom opset domain: '", custom_opset.first, "' provided is not used in the model. ",
      "Please verify custom opset domain names.");
    }
  }
}

void GraphEncoder::EncodeTensor(
    onnx::TensorProto* tensor_proto,
    const at::Tensor& tensor,
    const c10::optional<std::string> external_ref,
    const bool use_external_data_format,
    const std::string& onnx_file_path) {
  for (auto d : tensor.sizes()) {
    tensor_proto->add_dims(d);
  }
  tensor_proto->set_data_type(ATenTypeToOnnxType(tensor.scalar_type()));
  at::Tensor t;
  // CPU's HalfTensor doesn't have contiguous(), so first calling contiguous()
  // TODO We don't call .cpu() on quantized tensors as it fails when calling
  // aten::empty() on quantized tensors beyond certain size. Issue #29435.
  if (tensor.is_quantized()) {
    t = tensor.contiguous();
  }
  else {
    t = tensor.contiguous().cpu();
  }
  
  // Either defer_weight_export should be true and external_ref must be present,
  // or use_external_data_format should be true, not both at the same time. They can
  // both be false at the same time (for ONNX export for regular model size).
  AT_ASSERT(!((defer_weight_export_ && external_ref) && use_external_data_format));
  // Add a buffer to the raw_data_export_map for the caller to dump into an
  // external data store. If external_ref is not specified, we instead dump
  // the contiguous data into the protobuf itself
  if (defer_weight_export_ && external_ref) {
    // For now, we use the name of the tensor as the external lookup name to
    // avoid ONNX protobuf changes.
    AT_ASSERT(external_ref.value() == tensor_proto->name());
    AT_ASSERT(raw_data_export_map_.count(external_ref.value()) == 0);
    raw_data_export_map_[external_ref.value()] = t;
    tensor_proto->set_raw_data("__EXTERNAL");
  } else {
    AT_ASSERT(t.is_contiguous());
    size_t tensorSize = static_cast<size_t>(std::accumulate(std::begin(tensor.sizes()), 
                        std::end(tensor.sizes()), static_cast<int64_t>(1), std::multiplies<int64_t>()));
    if (use_external_data_format && tensorSize > ParamSizeThresholdForExternalStorage) {
      AT_ASSERT(!onnx_file_path.empty());
      AT_ASSERT((external_ref != c10::nullopt) && (external_ref.value() == tensor_proto->name()));
      auto tensorName = GetExternalFileName(external_ref);
      CreateExternalFile(t, tensorName, onnx_file_path);      
      onnx::StringStringEntryProto* location = tensor_proto->mutable_external_data()->Add();
      location->set_key("location");
      location->set_value(tensorName);
      tensor_proto->set_data_location(onnx::TensorProto_DataLocation_EXTERNAL);
    }
    else {
      tensor_proto->set_raw_data(std::string(
        static_cast<char*>(t.data_ptr()), t.element_size() * t.numel()));
    }
  }
}

// Pretty printing for ONNX
constexpr char indent_char = ' ';
constexpr size_t indent_multiplier = 2;

std::string idt(size_t indent) {
  return std::string(indent * indent_multiplier, indent_char);
}

std::string nlidt(size_t indent) {
  return std::string("\n") + idt(indent);
}

void dump(const onnx::TensorProto& tensor, std::ostream& stream) {
  stream << "TensorProto shape: [";
  for (int i = 0; i < tensor.dims_size(); ++i) {
    stream << tensor.dims(i) << (i == tensor.dims_size() - 1 ? "" : " ");
  }
  stream << "]";
}

void dump(const onnx::TensorShapeProto& shape, std::ostream& stream) {
  for (int i = 0; i < shape.dim_size(); ++i) {
    auto& dim = shape.dim(i);
    if (dim.has_dim_value()) {
      stream << dim.dim_value();
    } else {
      stream << "?";
    }
    stream << (i == shape.dim_size() - 1 ? "" : " ");
  }
}

void dump(const onnx::TypeProto_Tensor& tensor_type, std::ostream& stream) {
  stream << "Tensor dims: ";
  dump(tensor_type.shape(), stream);
}

void dump(const onnx::TypeProto& type, std::ostream& stream) {
  dump(type.tensor_type(), stream);
}

void dump(const onnx::ValueInfoProto& value_info, std::ostream& stream) {
  stream << "{name: \"" << value_info.name() << "\", type:";
  dump(value_info.type(), stream);
  stream << "}";
}

void dump(const onnx::GraphProto& graph, std::ostream& stream, size_t indent);

void dump(
    const onnx::AttributeProto& attr,
    std::ostream& stream,
    size_t indent) {
  stream << "{ name: '" << attr.name() << "', type: ";
  if (attr.has_f()) {
    stream << "float, value: " << attr.f();
  } else if (attr.has_i()) {
    stream << "int, value: " << attr.i();
  } else if (attr.has_s()) {
    stream << "string, value: '" << attr.s() << "'";
  } else if (attr.has_g()) {
    stream << "graph, value:\n";
    dump(attr.g(), stream, indent + 1);
    stream << nlidt(indent);
  } else if (attr.has_t()) {
    stream << "tensor, value:";
    dump(attr.t(), stream);
  } else if (attr.floats_size()) {
    stream << "floats, values: [";
    for (int i = 0; i < attr.floats_size(); ++i)
      stream << attr.floats(i) << (i == attr.floats_size() - 1 ? "" : " ");
    stream << "]";
  } else if (attr.ints_size()) {
    stream << "ints, values: [";
    for (int i = 0; i < attr.ints_size(); ++i)
      stream << attr.ints(i) << (i == attr.ints_size() - 1 ? "" : " ");
    stream << "]";
  } else if (attr.strings_size()) {
    stream << "strings, values: [";
    for (int i = 0; i < attr.strings_size(); ++i)
      stream << "'" << attr.strings(i) << "'"
             << (i == attr.strings_size() - 1 ? "" : " ");
    stream << "]";
  } else if (attr.tensors_size()) {
    stream << "tensors, values: [";
    for (auto& t : attr.tensors()) {
      dump(t, stream);
    }
    stream << "]";
  } else if (attr.graphs_size()) {
    stream << "graphs, values: [";
    for (auto& g : attr.graphs()) {
      dump(g, stream, indent + 1);
    }
    stream << "]";
  } else {
    stream << "UNKNOWN";
  }
  stream << "}";
}

void dump(const onnx::NodeProto& node, std::ostream& stream, size_t indent) {
  stream << "Node {type: \"" << node.op_type() << "\", inputs: [";
  for (int i = 0; i < node.input_size(); ++i) {
    stream << node.input(i) << (i == node.input_size() - 1 ? "" : ",");
  }
  stream << "], outputs: [";
  for (int i = 0; i < node.output_size(); ++i) {
    stream << node.output(i) << (i == node.output_size() - 1 ? "" : ",");
  }
  stream << "], attributes: [";
  for (int i = 0; i < node.attribute_size(); ++i) {
    dump(node.attribute(i), stream, indent + 1);
    stream << (i == node.attribute_size() - 1 ? "" : ",");
  }
  stream << "]}";
}

void dump(const onnx::GraphProto& graph, std::ostream& stream, size_t indent) {
  stream << idt(indent) << "GraphProto {" << nlidt(indent + 1) << "name: \""
         << graph.name() << "\"" << nlidt(indent + 1) << "inputs: [";
  for (int i = 0; i < graph.input_size(); ++i) {
    dump(graph.input(i), stream);
    stream << (i == graph.input_size() - 1 ? "" : ",");
  }
  stream << "]" << nlidt(indent + 1) << "outputs: [";
  for (int i = 0; i < graph.output_size(); ++i) {
    dump(graph.output(i), stream);
    stream << (i == graph.output_size() - 1 ? "" : ",");
  }
  stream << "]" << nlidt(indent + 1) << "initializers: [";
  for (int i = 0; i < graph.initializer_size(); ++i) {
    dump(graph.initializer(i), stream);
    stream << (i == graph.initializer_size() - 1 ? "" : ",");
  }
  stream << "]" << nlidt(indent + 1) << "nodes: [" << nlidt(indent + 2);
  for (int i = 0; i < graph.node_size(); ++i) {
    dump(graph.node(i), stream, indent + 2);
    if (i != graph.node_size() - 1)
      stream << "," << nlidt(indent + 2);
  }
  stream << nlidt(indent + 1) << "]\n" << idt(indent) << "}\n";
}

void dump(
    const onnx::OperatorSetIdProto& operator_set_id,
    std::ostream& stream) {
  stream << "OperatorSetIdProto { domain: " << operator_set_id.domain() << "}";
}

void dump(const onnx::ModelProto& model, std::ostream& stream, size_t indent) {
  stream << idt(indent) << "ModelProto {" << nlidt(indent + 1)
         << "producer_name: \"" << model.producer_name() << "\""
         << nlidt(indent + 1) << "domain: \"" << model.domain() << "\""
         << nlidt(indent + 1) << "doc_string: \"" << model.doc_string() << "\"";
  if (model.has_graph()) {
    stream << nlidt(indent + 1) << "graph:\n";
    dump(model.graph(), stream, indent + 2);
  }
  if (model.opset_import_size()) {
    stream << idt(indent + 1) << "opset_import: [";
    for (auto& opset_imp : model.opset_import()) {
      dump(opset_imp, stream);
    }
    stream << "],\n";
  }
  stream << idt(indent) << "}\n";
}

std::string prettyPrint(const onnx::ModelProto& model) {
  std::ostringstream ss;
  dump(model, ss, 0);
  return ss.str();
}

} // namespace

std::string pretty_print_onnx(
    const std::shared_ptr<Graph>& graph,
    const std::map<std::string, at::Tensor>& initializers,
    int64_t onnx_opset_version,
    bool defer_weight_export,
    ::torch::onnx::OperatorExportTypes operator_export_type,
    bool google_printer,
    bool keep_initializers_as_inputs,
    const std::map<std::string, int>& custom_opsets,
    bool add_node_names) {
  auto graph_encoder = GraphEncoder(
      graph,
      onnx_opset_version,
      operator_export_type,
      initializers,
      std::unordered_map<std::string, std::unordered_map<int64_t, std::string>>{},
      defer_weight_export,
      true,
      keep_initializers_as_inputs,
      custom_opsets,
      add_node_names,
      false,
      std::string());
  if (google_printer) {
    return graph_encoder.get_model_proto().DebugString();
  }
  return prettyPrint(graph_encoder.get_model_proto());
}

// export_raw_ir will export IR ops without turning them into ONNX ops.
// The output will use the ONNX protobuf format, but the ops will not
// conform to the ONNX op specification. Thus, the output will not
// be interpretable by a ONNX-compatible framework. However, PyTorch or
// libtorch will be able to import the IR and play it back.
std::tuple<std::string, RawDataExportMap> export_onnx(
    const std::shared_ptr<Graph>& graph,
    const std::map<std::string, at::Tensor>& initializers,
    int64_t onnx_opset_version,
    const std::unordered_map<std::string, std::unordered_map<std::int64_t, std::string>>& dynamic_axes,
    bool defer_weight_export,
    ::torch::onnx::OperatorExportTypes operator_export_type,
    bool strip_doc_string,
    bool keep_initializers_as_inputs,
    const std::map<std::string, int>& custom_opsets,
    bool add_node_names,
    bool use_external_data_format,
    const std::string& onnx_file_path) {
  auto graph_encoder = GraphEncoder(
      graph,
      onnx_opset_version,
      operator_export_type,
      initializers,
      dynamic_axes,
      defer_weight_export,
      strip_doc_string,
      keep_initializers_as_inputs,
      custom_opsets,
      add_node_names,
      use_external_data_format,
      onnx_file_path);
  return std::make_tuple(
      graph_encoder.get_model_proto().SerializeAsString(),
      graph_encoder.get_raw_data_export_map());
}

void check_onnx_proto(const std::string& proto_string) {
    onnx::ModelProto model;
    if (!ParseProtoFromBytes(&model, proto_string.c_str(), proto_string.size())) {
        throw std::runtime_error("Invalid ONNX proto string.");
        return;
    }
    onnx::checker::check_model(model);
}

namespace {
void export_opnames(const script::Module& m, std::set<std::string>& opnames) {
  for (const auto& method : m.get_methods()) {
    const auto& func = method.function();
    for (const auto& node : func.graph()->nodes()) {
      auto schema = node->maybeSchema();
      if (schema) {
        auto opname = schema->operator_name();
        std::string namestr = opname.name;
        if (!opname.overload_name.empty()) {
          namestr += "." + opname.overload_name;
        }
        opnames.emplace(namestr);
      }
    }
  }
  for (const auto& sub_m : m.children()) {
    export_opnames(sub_m, opnames);
  }
}
} // namespace

std::vector<std::string> export_opnames(const script::Module& m) {
  std::set<std::string> names;
  export_opnames(m, names);
  return std::vector<std::string>(names.begin(), names.end());
}

} // namespace jit
} // namespace torch
