/*
All modification made by Intel Corporation: © 2016 Intel Corporation

All contributions by the University of California:
Copyright (c) 2014, 2015, The Regents of the University of California (Regents)
All rights reserved.

All other contributions:
Copyright (c) 2014, 2015, the respective contributors
All rights reserved.
For the list of contributors go to https://github.com/BVLC/caffe/blob/master/CONTRIBUTORS.md


Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of Intel Corporation nor the names of its contributors
      may be used to endorse or promote products derived from this software
      without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <algorithm>
#include <map>
#include <sstream>
#include <string>
#include <utility>

#include "caffe/common.hpp"
#include "caffe/util/insert_splits.hpp"

namespace caffe {

void InsertSplits(const NetParameter& param, NetParameter* param_split) {
  // Initialize by copying from the input NetParameter.
  param_split->CopyFrom(param);
  param_split->clear_layer();
  map<string, pair<int, int> > blob_name_to_last_top_idx;
  map<pair<int, int>, pair<int, int> > bottom_idx_to_source_top_idx;
  map<pair<int, int>, int> top_idx_to_bottom_count;
  map<pair<int, int>, float> top_idx_to_loss_weight;
  map<pair<int, int>, int> top_idx_to_bottom_split_idx;
  map<int, string> layer_idx_to_layer_name;
  for (int i = 0; i < param.layer_size(); ++i) {
    const LayerParameter& layer_param = param.layer(i);
    layer_idx_to_layer_name[i] = layer_param.name();
    for (int j = 0; j < layer_param.bottom_size(); ++j) {
      const string& blob_name = layer_param.bottom(j);
      if (blob_name_to_last_top_idx.find(blob_name) ==
          blob_name_to_last_top_idx.end()) {
        LOG(FATAL) << "Unknown bottom blob '" << blob_name << "' (layer '"
                   << layer_param.name() << "', bottom index " << j << ")";
      }
      const pair<int, int>& bottom_idx = make_pair(i, j);
      const pair<int, int>& top_idx = blob_name_to_last_top_idx[blob_name];
      bottom_idx_to_source_top_idx[bottom_idx] = top_idx;
      ++top_idx_to_bottom_count[top_idx];
    }
    for (int j = 0; j < layer_param.top_size(); ++j) {
      const string& blob_name = layer_param.top(j);
      blob_name_to_last_top_idx[blob_name] = make_pair(i, j);
    }
    // A use of a top blob as a loss should be handled similarly to the use of
    // a top blob as a bottom blob to another layer.
    const int last_loss =
        std::min(layer_param.loss_weight_size(), layer_param.top_size());
    for (int j = 0; j < last_loss; ++j) {
      const string& blob_name = layer_param.top(j);
      const pair<int, int>& top_idx = blob_name_to_last_top_idx[blob_name];
      top_idx_to_loss_weight[top_idx] = layer_param.loss_weight(j);
      if (top_idx_to_loss_weight[top_idx]) {
        ++top_idx_to_bottom_count[top_idx];
      }
    }
  }
  for (int i = 0; i < param.layer_size(); ++i) {
    LayerParameter* layer_param = param_split->add_layer();
    layer_param->CopyFrom(param.layer(i));
    // Replace any shared bottom blobs with split layer outputs.
    for (int j = 0; j < layer_param->bottom_size(); ++j) {
      const pair<int, int>& top_idx =
          bottom_idx_to_source_top_idx[make_pair(i, j)];
      const int split_count = top_idx_to_bottom_count[top_idx];
      if (split_count > 1) {
        const string& layer_name = layer_idx_to_layer_name[top_idx.first];
        const string& blob_name = layer_param->bottom(j);
        layer_param->set_bottom(j, SplitBlobName(layer_name,
            blob_name, top_idx.second, top_idx_to_bottom_split_idx[top_idx]++));
      }
    }
    // Create split layer for any top blobs used by other layer as bottom
    // blobs more than once.
    for (int j = 0; j < layer_param->top_size(); ++j) {
      const pair<int, int>& top_idx = make_pair(i, j);
      const int split_count = top_idx_to_bottom_count[top_idx];
      if (split_count > 1) {
        const string& layer_name = layer_idx_to_layer_name[i];
        const string& blob_name = layer_param->top(j);
        LayerParameter* split_layer_param = param_split->add_layer();
        const float loss_weight = top_idx_to_loss_weight[top_idx];
        ConfigureSplitLayer(layer_name, blob_name, j, split_count,
            loss_weight, split_layer_param);
        if (loss_weight) {
          layer_param->clear_loss_weight();
          top_idx_to_bottom_split_idx[top_idx]++;
        }
      }
    }
  }
}

void ConfigureSplitLayer(const string& layer_name, const string& blob_name,
    const int blob_idx, const int split_count, const float loss_weight,
    LayerParameter* split_layer_param) {
  split_layer_param->Clear();
  split_layer_param->add_bottom(blob_name);
  split_layer_param->set_name(SplitLayerName(layer_name, blob_name, blob_idx));
  split_layer_param->set_type("Split");
  for (int k = 0; k < split_count; ++k) {
    split_layer_param->add_top(
        SplitBlobName(layer_name, blob_name, blob_idx, k));
    if (loss_weight) {
      if (k == 0) {
        split_layer_param->add_loss_weight(loss_weight);
      } else {
        split_layer_param->add_loss_weight(0);
      }
    }
  }
}

string SplitLayerName(const string& layer_name, const string& blob_name,
    const int blob_idx) {
  ostringstream split_layer_name;
  split_layer_name << blob_name << "_" << layer_name << "_" << blob_idx
      << "_split";
  return split_layer_name.str();
}

string SplitBlobName(const string& layer_name, const string& blob_name,
    const int blob_idx, const int split_idx) {
  ostringstream split_blob_name;
  split_blob_name << blob_name << "_" << layer_name << "_" << blob_idx
      << "_split_" << split_idx;
  return split_blob_name.str();
}

}  // namespace caffe
