/* Copyright (c) 2016 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 <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <fstream>
#include <iostream>
#include <algorithm>
#include <utility>
#include "google/protobuf/message.h"
#include "google/protobuf/text_format.h"
#include "google/protobuf/io/zero_copy_stream_impl.h"

#include "gflags/gflags.h"
#include "paddle/fluid/framework/feed_fetch_method.h"
#include "paddle/fluid/framework/feed_fetch_type.h"
#include "paddle/fluid/framework/lod_rank_table.h"
#include "paddle/fluid/framework/lod_tensor.h"
#include "paddle/fluid/framework/op_registry.h"
#include "paddle/fluid/framework/reader.h"
#include "paddle/fluid/platform/place.h"
#include "paddle/fluid/platform/profiler.h"
#include "paddle/fluid/framework/data_feed.h"

DEFINE_bool(is_text_feed, false, "is_text_feed");

namespace paddle {
namespace framework {
std::vector<std::string> MultiSlotDataFeed::s_filelist_;
std::mutex MultiSlotDataFeed::s_locker_for_pick_file_;
unsigned int MultiSlotDataFeed::s_current_file_idx_ = 0;
size_t MultiSlotDataFeed::s_current_finished_file_cnt_ = 0;
unsigned int MultiSlotDataFeed::s_current_epoch_ = 0;
int MultiSlotDataFeed::s_current_save_epoch_ = 0;
std::mutex MultiSlotDataFeed::s_locker_epoch_start_;
std::condition_variable MultiSlotDataFeed::s_condition_epoch_start_;
bool MultiSlotDataFeed::s_epoch_start_flag_ = false;

void MultiSlotDataFeed::Init() {
  // hard coding for a specific datafeed
  feed_vec_.resize(2);
  // feed_vec_[0].reset(new LoDTensor);
  // feed_vec_[1].reset(new LoDTensor);
  all_slot_ids_ = {0, 1};
  use_slot_ids_ = {0, 1};
  use_slot_alias_ = {"words", "label"};

  file_content_buffer_host_.reset(new char[200*1024*1024],
                                  [](char *p) {delete[] p;});
  file_content_buffer_ = file_content_buffer_host_.get();
  file_content_buffer_ptr_ = file_content_buffer_;

  batch_id_host_.reset(new int[10240*1024],
                      [](int *p) {delete[] p;});  // max word num in a batch
  batch_id_buffer_ = batch_id_host_.get();

  label_host_.reset(new int[10240],
                    [](int *p) {delete[] p;});    // max label in a batch
  label_ptr_ = label_host_.get();

  field_names_.clear();
}

MultiSlotDataFeed::MultiSlotDataFeed() {
  Init();
}

  // todo: use elegant implemention for this function
bool MultiSlotDataFeed::ReadBatch() {
  paddle::framework::Vector<size_t> offset;
  int tlen = 0;
  int llen = 0;
  int inst_idx = 0;
  offset.resize(batch_size_ + 1);
  offset[0] = 0;

  while (inst_idx < batch_size_) {
    int ptr_offset = 0;
    if (file_content_buffer_ptr_ - file_content_buffer_ >= file_size_) {
      break;
    }

    memcpy(reinterpret_cast<char *>(&llen),
          file_content_buffer_ptr_ + ptr_offset,
          sizeof(int));
    ptr_offset += sizeof(int);

    memcpy(reinterpret_cast<char *>(batch_id_buffer_ + tlen),
          file_content_buffer_ptr_ + ptr_offset,
          llen * sizeof(int));
    tlen += llen;

    offset[inst_idx + 1] = offset[inst_idx] + llen;
    ptr_offset += sizeof(int) * llen;

    memcpy(reinterpret_cast<char *>(label_ptr_ + inst_idx),
          file_content_buffer_ptr_ + ptr_offset,
          sizeof(int));
    ptr_offset += sizeof(int);

    file_content_buffer_ptr_ += ptr_offset;
    inst_idx++;
  }

  if (inst_idx != batch_size_) {
    return false;
  }

  LoD input_lod{offset};
  paddle::framework::Vector<size_t> label_offset;
  label_offset.resize(batch_size_ + 1);
  for (int i = 0; i <= batch_size_; ++i) {
    label_offset[i] = i;
  }

  LoD label_lod{label_offset};
  int64_t* input_ptr = feed_vec_[0]->mutable_data<int64_t>(
      {static_cast<int64_t>(offset.back()), 1},
      platform::CPUPlace());
  int64_t* label_ptr = feed_vec_[1]->mutable_data<int64_t>({batch_size_, 1},
                                                          platform::CPUPlace());
  for (unsigned int i = 0; i < offset.back(); ++i) {
    input_ptr[i] = static_cast<int64_t>(batch_id_buffer_[i]);
  }
  for (int i = 0; i < batch_size_; ++i) {
    label_ptr[i] = static_cast<int64_t>(label_ptr_[i]);
  }
  feed_vec_[0]->set_lod(input_lod);
  feed_vec_[1]->set_lod(label_lod);
  return true;
}

MultiSlotDataFeed::MultiSlotDataFeed(const MultiSlotDataFeed& data_feed) {
  Init();
  SetBatchSize(data_feed.batch_size_);
  SetFieldNames(data_feed.field_names_);
}

void MultiSlotDataFeed::AddFeedVar(Variable* feed, const std::string& name) {
  for (unsigned int i = 0; i < use_slot_alias_.size(); ++i) {
    if (name == use_slot_alias_[i]) {
      feed_vec_[i] = feed->GetMutable<LoDTensor>();
    }
  }
}

void MultiSlotDataFeed::SetFileList(const char* filelist) {
  s_filelist_.clear();
  std::ifstream fin(filelist);
  PADDLE_ENFORCE(fin.good(),
                 "Opening file %s fail",
                 filelist);
  std::string filename;
  while (fin >> filename) {
    LOG(ERROR) << "add " << filename.c_str() << " to filelist";
    s_filelist_.push_back(filename);
  }
  fin.close();
}

void MultiSlotDataFeed::SetFieldNames(
    const std::vector<std::string>& field_names) {
  field_names_.clear();
  field_names_.insert(field_names_.end(), field_names.begin(),
                      field_names.end());
}

bool MultiSlotDataFeed::SetFile(const char* filename) {
  // termnum termid termid ... termid label
  std::ifstream ifs(filename, std::ios::binary);
  if (ifs.fail()) {
    return false;
  }

  ifs.seekg(0, std::ios::end);
  int filesize = ifs.tellg();
  ifs.seekg(0, std::ios::beg);
  ifs.read(file_content_buffer_, filesize);
  if (filesize < 0 || filesize >= 1024 * 1024 * 1024) {
    return false;
  }
  file_content_buffer_ptr_ = file_content_buffer_;
  file_size_ = filesize;
  // todo , remove magic number

  return true;
}

void MultiSlotDataFeed::UpdateEpochNum() {
  s_current_finished_file_cnt_++;

  if (s_current_finished_file_cnt_ >= s_filelist_.size()) {
    s_current_finished_file_cnt_ = 0;
    s_current_epoch_++;
#if 1
    LOG(WARNING) << "UpdateEpochNum: epoch = " << s_current_epoch_;
#endif
    {
      std::lock_guard<std::mutex> lock(s_locker_epoch_start_);
      s_epoch_start_flag_ = false;
    }
  }
}

void MultiSlotDataFeed::Start() {
}

int MultiSlotDataFeed::Next() {
  return 0;
}

const char* MultiSlotDataFeed::PickOneFile() {
  std::string file_to_be_processed;
  std::lock_guard<std::mutex> lock(s_locker_for_pick_file_);

  // One epoch has run over
  // Wait for next epoch
  if (s_current_file_idx_ >= s_filelist_.size()) {
    LOG(ERROR) << "thread " << thread_id_
               << ": finish traing for epoch " << s_current_epoch_ + 1;

    return NULL;
  }

  file_to_be_processed = s_filelist_[s_current_file_idx_];

  s_current_file_idx_++;
  return file_to_be_processed.c_str();
}

}   // namespace framework
}   // namespace paddle
/* vim: set expandtab ts=2 sw=2 sts=2 tw=100: */