/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

/*!
 *  Copyright (c) 2017 by Contributors
 *
 * \brief Tiny graph runtime that can run graph
 *        containing only tvm PackedFunc.
 * \file graph_runtime.h
 */
#ifndef TVM_RUNTIME_GRAPH_GRAPH_RUNTIME_H_
#define TVM_RUNTIME_GRAPH_GRAPH_RUNTIME_H_

#include <dlpack/dlpack.h>
#include <dmlc/memory_io.h>
#include <dmlc/json.h>
#include <tvm/runtime/ndarray.h>
#include <tvm/runtime/packed_func.h>

#include <memory>
#include <utility>
#include <vector>
#include <string>

namespace tvm {
namespace runtime {

/*! \brief macro to do C API call */
#define TVM_CCALL(func)                                            \
  {                                                                \
    int ret = (func);                                              \
    CHECK_EQ(ret, 0)                                               \
        << TVMGetLastError();                                      \
  }

/*! \brief Magic number for NDArray list file  */
constexpr uint64_t kTVMNDArrayListMagic = 0xF7E58D4F05049CB7;

/*! \brief operator attributes about tvm op */
struct TVMOpParam {
  std::string func_name;
  uint32_t num_inputs;
  uint32_t num_outputs;
  uint32_t flatten_data;
};

/*!
 * \brief Tiny graph runtime.
 *
 *  This runtime can be acccesibly in various language via
 *  TVM runtime PackedFunc API.
 */
class GraphRuntime : public ModuleNode {
 public:
  /*!
   * \brief Get member function to front-end
   * \param name The name of the function.
   * \param sptr_to_self The pointer to the module node.
   * \return The corresponding member function.
   */
  virtual PackedFunc GetFunction(const std::string& name,
                                 const std::shared_ptr<ModuleNode>& sptr_to_self);

  /*!
   * \return The type key of the executor.
   */
  const char* type_key() const final {
    return "GraphRuntime";
  }
  void Run();

  /*!
   * \brief Initialize the graph executor with graph and context.
   * \param graph_json The execution graph.
   * \param module The module containing the compiled functions for the host
   *  processor.
   * \param ctxs The context of the host and devices where graph nodes will be
   *  executed on.
   */

  void Init(const std::string& graph_json,
            tvm::runtime::Module module,
            const std::vector<TVMContext>& ctxs);

  /*!
   * \brief Get the input index given the name of input.
   * \param name The name of the input.
   * \return The index of input.
   */
  int GetInputIndex(const std::string& name);

  /*!
   * \brief set index-th input to the graph.
   * \param index The input index.
   * \param data_in The input data.
   */
  void SetInput(int index, DLTensor* data_in);
  /*!
   * \brief Get the number of outputs
   *
   * \return The number of outputs from graph.
   */
  int NumOutputs() const;
  /*!
   * \brief Return NDArray for given input index.
   * \param index The input index.
   *
   * \return NDArray corresponding to given input node index.
   */
  NDArray GetInput(int index) const;
  /*!
   * \brief Return NDArray for given output index.
   * \param index The output index.
   *
   * \return NDArray corresponding to given output node index.
   */
  NDArray GetOutput(int index) const;
  /*!
   * \brief Copy index-th output to data_out.
   * \param index The output index.
   * \param data_out the output data.
   */
  void CopyOutputTo(int index, DLTensor* data_out);
  /*!
   * \brief Load parameters from binary stream
   * \param strm The input stream.
   */
  void LoadParams(dmlc::Stream* strm);
  /*!
   * \brief Load parameters from parameter blob.
   * \param param_blob A binary blob of parameter.
   */
  void LoadParams(const std::string& param_blob);
 /*!
  * \brief Get total number of nodes.
  * \return Total number of nodes.
  */
  uint32_t GetNumOfNodes() const {
    return static_cast<uint32_t>(nodes_.size());
  }

  std::string GetNodeName(uint32_t nid) const {
    return nodes_[nid].name;
  }


 protected:
  // Memory pool entry.
  struct PoolEntry {
    size_t size;
    int device_type;
    PoolEntry(int s, int dev_type) : size(s), device_type(dev_type) {}
  };
  // Node entry
  struct NodeEntry {
    uint32_t node_id;
    uint32_t index;
    uint32_t version;
    // JSON Loader
    void Load(dmlc::JSONReader *reader) {
      reader->BeginArray();
      CHECK(reader->NextArrayItem()) << "invalid json format";
      reader->Read(&node_id);
      CHECK(reader->NextArrayItem()) << "invalid json format";
      reader->Read(&index);
      if (reader->NextArrayItem()) {
        reader->Read(&version);
        CHECK(!reader->NextArrayItem()) << "invalid json format";
      } else {
        version = 0;
      }
    }
  };
  // Node
  struct Node {
    // operator type in string
    std::string op_type;
    // name of the op
    std::string name;
    // parameters
    TVMOpParam param;
    // inputs
    std::vector<NodeEntry> inputs;
    // control deps
    std::vector<uint32_t> control_deps;
    // JSON Loader
    void LoadAttrs(dmlc::JSONReader *reader, TVMOpParam* param) {
      int bitmask = 0;
      std::string key, value;
      reader->BeginObject();
      while (reader->NextObjectItem(&key)) {
        reader->Read(&value);
        if (key == "func_name") {
          param->func_name = value;
          bitmask |= 1;
        } else if (key == "num_inputs") {
          param->num_inputs = strtoul(value.c_str(), nullptr, 10);
          bitmask |= 2;
        } else if (key == "num_outputs") {
          param->num_outputs = strtoul(value.c_str(), nullptr, 10);
          bitmask |= 4;
        } else if (key == "flatten_data") {
          param->flatten_data = strtoul(value.c_str(), nullptr, 10);
          bitmask |= 8;
        }
      }
      CHECK_EQ(bitmask, 1|2|4|8) << "invalid format";
    }
    // JSON Loader
    void Load(dmlc::JSONReader *reader) {
      reader->BeginObject();
      int bitmask = 0;
      std::string key;
      while (reader->NextObjectItem(&key)) {
        if (key == "op") {
          reader->Read(&op_type);
          bitmask |= 1;
        } else if (key == "name") {
          reader->Read(&name);
          bitmask |= 2;
        } else if (key == "inputs") {
          reader->Read(&inputs);
          bitmask |= 4;
        } else if (key == "attr" || key == "attrs") {
          this->LoadAttrs(reader, &param);
        } else if (key == "control_deps") {
          reader->Read(&control_deps);
        } else {
          LOG(FATAL) << "do not support key " << key;
        }
      }
      CHECK_EQ(bitmask, 1|2|4) << "invalid format";
    }
  };
  struct GraphAttr {
    size_t storage_num_not_alloctaed{0};
    std::vector<int> storage_id;
    std::vector<int> device_index;
    std::vector<std::string> dltype;
    std::vector<std::vector<int64_t> > shape;
    // The graph attribute fields.
    void Load(dmlc::JSONReader *reader) {
      reader->BeginObject();
      int bitmask = 0;
      std::string key, type;
      while (reader->NextObjectItem(&key)) {
        if (key == "dltype") {
          reader->BeginArray();
          CHECK(reader->NextArrayItem());
          reader->Read(&type);
          CHECK_EQ(type, "list_str");
          CHECK(reader->NextArrayItem());
          reader->Read(&dltype);
          CHECK(!reader->NextArrayItem());
          bitmask |= 1;
        } else if (key == "storage_id") {
          reader->BeginArray();
          CHECK(reader->NextArrayItem());
          reader->Read(&type);
          CHECK_EQ(type, "list_int");
          CHECK(reader->NextArrayItem());
          reader->Read(&storage_id);
          CHECK(!reader->NextArrayItem());
          bitmask |= 2;
        } else if (key == "shape") {
          reader->BeginArray();
          CHECK(reader->NextArrayItem());
          reader->Read(&type);
          CHECK_EQ(type, "list_shape");
          CHECK(reader->NextArrayItem());
          reader->Read(&shape);
          CHECK(!reader->NextArrayItem());
          bitmask |= 4;
        } else if (key == "device_index") {
          reader->BeginArray();
          CHECK(reader->NextArrayItem());
          reader->Read(&type);
          CHECK_EQ(type, "list_int");
          CHECK(reader->NextArrayItem());
          reader->Read(&device_index);
          CHECK(!reader->NextArrayItem());
        } else {
          reader->BeginArray();
          CHECK(reader->NextArrayItem());
          reader->Read(&type);
          if (type == "list_int") {
            CHECK(reader->NextArrayItem());
            std::vector<int> temp;
            reader->Read(&temp);
          } else if (type == "size_t") {
            CHECK(reader->NextArrayItem());
            size_t temp;
            reader->Read(&temp);
          } else {
            LOG(FATAL) << "cannot skip graph attr " << key;
          }
          CHECK(!reader->NextArrayItem());
        }
      }
      CHECK_EQ(bitmask, 1|2|4) << "invalid format";
    }
  };
  // The graph attribute fields.
  void Load(dmlc::JSONReader *reader) {
      reader->BeginObject();
      int bitmask = 0;
      std::string key;
      while (reader->NextObjectItem(&key)) {
        if (key == "nodes") {
          reader->Read(&nodes_);
          bitmask |= 1;
        } else if (key == "arg_nodes") {
          reader->Read(&input_nodes_);
          bitmask |= 2;
        } else if (key == "node_row_ptr") {
          reader->Read(&node_row_ptr_);
          bitmask |= 4;
        } else if (key == "heads") {
          reader->Read(&outputs_);
          bitmask |= 8;
        } else if (key == "attrs") {
          reader->Read(&attrs_);
          bitmask |= 16;
        } else if (key == "metadata") {
          break;
        } else {
          LOG(FATAL) << "key " << key << " is not supported";
        }
      }
      CHECK_EQ(bitmask, 1|2|4|8|16) << "invalid format";
  }
  /*! \brief Setup the temporal storage */
  void SetupStorage();
  /*! \brief Setup the executors. */
  void SetupOpExecs();
  /*!
   * \brief Create an execution function given input.
   * \param attrs The node attributes.
   * \param args The arguments to the functor, including inputs and outputs.
   * \param num_inputs Number of inputs.
   * \return The created executor.
   */
  std::function<void()> CreateTVMOp(const TVMOpParam& attrs,
                                    const std::vector<DLTensor>& args,
                                    size_t num_inputs);
  // Get node entry index.
  uint32_t entry_id(uint32_t nid, uint32_t index) const {
    return node_row_ptr_[nid] + index;
  }
  // Get node entry index.
  uint32_t entry_id(const NodeEntry& e) const {
    return entry_id(e.node_id, e.index);
  }
  // Number of node entries.
  uint32_t num_node_entries() const {
    return node_row_ptr_.back();
  }
  /*! \brief The graph nodes. */
  std::vector<Node> nodes_;
  /*! \brief The argument nodes. */
  std::vector<uint32_t> input_nodes_;
  /*! \brief Used for quick entry indexing. */
  std::vector<uint32_t> node_row_ptr_;
  /*! \brief Output entries. */
  std::vector<NodeEntry> outputs_;
  /*! \brief Additional graph attributes. */
  GraphAttr attrs_;
  /*! \brief The code module that contains both host and device code. */
  tvm::runtime::Module module_;
  /*! \brief Execution context of all devices including the host. */
  std::vector<TVMContext> ctxs_;
  /*! \brief Common storage pool for all devices. */
  std::vector<NDArray> storage_pool_;
  /*! \brief Data entry of each node. */
  std::vector<NDArray> data_entry_;
  /*! \brief Operator on each node. */
  std::vector<std::function<void()> > op_execs_;
};

std::vector<TVMContext> GetAllContext(const TVMArgs& args);
}  // namespace runtime
}  // namespace tvm

#endif  // TVM_RUNTIME_GRAPH_GRAPH_RUNTIME_H_
