// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed 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.

#include <gflags/gflags.h>
#include <glog/logging.h>
#include <paddle_inference_api.h>
#include <chrono>
#include <iostream>
#include <fstream>
#include <numeric>
#include <sstream>
#include <string>
#include <vector>

DEFINE_string(model_dir, "", "Inference model directory.");
DEFINE_string(data, "", "Input data path.");
DEFINE_int32(repeat, 1, "Repeat times.");
DEFINE_int32(num_labels, 3, "Number of labels.");
DEFINE_bool(output_prediction, false, "Whether to output the prediction results.");
DEFINE_bool(use_gpu, false, "Whether to use GPU for prediction.");

template <typename T>
void GetValueFromStream(std::stringstream *ss, T *t) {
  (*ss) >> (*t);
}

template <>
void GetValueFromStream<std::string>(std::stringstream *ss, std::string *t) {
  *t = ss->str();
}

// Split string to vector
template <typename T>
void Split(const std::string &line, char sep, std::vector<T> *v) {
  std::stringstream ss;
  T t;
  for (auto c : line) {
    if (c != sep) {
      ss << c;
    } else {
      GetValueFromStream<T>(&ss, &t);
      v->push_back(std::move(t));
      ss.str({});
      ss.clear();
    }
  }

  if (!ss.str().empty()) {
    GetValueFromStream<T>(&ss, &t);
    v->push_back(std::move(t));
    ss.str({});
    ss.clear();
  }
}

template <typename T>
constexpr paddle::PaddleDType GetPaddleDType();

template <>
constexpr paddle::PaddleDType GetPaddleDType<int64_t>() {
  return paddle::PaddleDType::INT64;
}

template <>
constexpr paddle::PaddleDType GetPaddleDType<float>() {
  return paddle::PaddleDType::FLOAT32;
}


// Parse tensor from string
template <typename T>
bool ParseTensor(const std::string &field, paddle::PaddleTensor *tensor) {
  std::vector<std::string> data;
  Split(field, ':', &data);
  if (data.size() < 2) {
    LOG(ERROR) << "parse tensor error!";
    return false;
  }

  std::string shape_str = data[0];

  std::vector<int> shape;
  Split(shape_str, ' ', &shape);

  std::string mat_str = data[1];

  std::vector<T> mat;
  Split(mat_str, ' ', &mat);

  tensor->shape = shape;
  auto size =
      std::accumulate(shape.begin(), shape.end(), 1, std::multiplies<int>()) *
      sizeof(T);
  tensor->data.Resize(size);
  std::copy(mat.begin(), mat.end(), static_cast<T *>(tensor->data.data()));
  tensor->dtype = GetPaddleDType<T>();

  return true;
}

// Parse input tensors from string
bool ParseLine(const std::string &line,
               std::vector<paddle::PaddleTensor> *tensors) {
  std::vector<std::string> fields;
  Split(line, ';', &fields);

  if (fields.size() < 4) return false;

  tensors->clear();
  tensors->reserve(4);

  int i = 0;
  // src_id
  paddle::PaddleTensor src_id;
  ParseTensor<int64_t>(fields[i++], &src_id);
  tensors->push_back(src_id);

  // pos_id
  paddle::PaddleTensor pos_id;
  ParseTensor<int64_t>(fields[i++], &pos_id);
  tensors->push_back(pos_id);

  // segment_id
  paddle::PaddleTensor segment_id;
  ParseTensor<int64_t>(fields[i++], &segment_id);
  tensors->push_back(segment_id);

  // input mask
  paddle::PaddleTensor input_mask;
  ParseTensor<float>(fields[i++], &input_mask);
  tensors->push_back(input_mask);

  return true;
}

template <typename T>
void PrintTensor(const paddle::PaddleTensor &t) {
  std::stringstream ss;
  ss.str({});
  ss.clear();
  ss << "Tensor: shape[";
  for (auto i: t.shape) {
    ss << i << " ";
  }
  ss << "], data[";
  T *data = static_cast<T *>(t.data.data());
  for (int i = 0; i < t.data.length() / sizeof(T); i++) {
    ss << data[i] << " ";
  }

  ss << "]";
  LOG(INFO) << ss.str();
}

void PrintInputs(const std::vector<paddle::PaddleTensor> &inputs) {
  for (const auto &t : inputs) {
    if (t.dtype == paddle::PaddleDType::INT64) {
      PrintTensor<int64_t>(t);
    } else {
      PrintTensor<float>(t);
    }
  }
}

// Print outputs to log
void PrintOutputs(const std::vector<paddle::PaddleTensor> &outputs, int &cnt) {
  for (size_t i = 0; i < outputs.front().data.length() / sizeof(float); 
       i += FLAGS_num_labels) {
    std::cout << cnt << "\t";
    for (size_t j = 0; j < FLAGS_num_labels; ++j) {
      std::cout  << static_cast<float *>(outputs.front().data.data())[i+j] << "\t";
    }
    std::cout << std::endl;
    cnt += 1;
  }
}

bool LoadInputData(std::vector<std::vector<paddle::PaddleTensor>> *inputs) {
  if (FLAGS_data.empty()) {
    LOG(ERROR) << "please set input data path";
    return false;
  }

  std::ifstream fin(FLAGS_data);
  std::string line;

  int lineno = 0;
  while (std::getline(fin, line)) {
    std::vector<paddle::PaddleTensor> feed_data;
    if (!ParseLine(line, &feed_data)) {
      LOG(ERROR) << "Parse line[" << lineno << "] error!";
    } else {
      inputs->push_back(std::move(feed_data));
    }
  }

  return true;
}

int main(int argc, char *argv[]) {
  google::InitGoogleLogging(*argv);
  gflags::ParseCommandLineFlags(&argc, &argv, true);

  if (FLAGS_model_dir.empty()) {
    LOG(ERROR) << "please set model dir";
    return -1;
  }

  paddle::NativeConfig config;
  config.model_dir = FLAGS_model_dir;
  if (FLAGS_use_gpu) {
    config.use_gpu = true;
    config.fraction_of_gpu_memory = 0.15;
    config.device = 0;
  }

  auto predictor = CreatePaddlePredictor(config);

  std::vector<std::vector<paddle::PaddleTensor>> inputs;
  if (!LoadInputData(&inputs)) {
    LOG(ERROR) << "load input data error!";
    return -1;
  }

  std::vector<paddle::PaddleTensor> fetch;
  int total_time{0};
  int num_samples{0};
  int out_cnt = 0;
  for (int i = 0; i < FLAGS_repeat; i++) {
    for (auto feed : inputs) {
      fetch.clear();
      auto start = std::chrono::system_clock::now();
      predictor->Run(feed, &fetch);
      if (FLAGS_output_prediction && i == 0) {
	PrintOutputs(fetch, out_cnt);
      }
      auto end = std::chrono::system_clock::now();
      if (!fetch.empty()) {
        total_time +=
            std::chrono::duration_cast<std::chrono::milliseconds>(end - start)
                .count();
        num_samples += fetch.front().data.length() / FLAGS_num_labels / sizeof(float);
      }
    }
  }
  

  auto per_sample_ms =
      static_cast<float>(total_time) / num_samples;
  LOG(INFO) << "Run on " << num_samples 
            << " samples over "<< FLAGS_repeat << " times, average latency: " << per_sample_ms
            << "ms per sample.";

  return 0;
}