/* 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 "paddle/fluid/framework/ir/fusion_group/code_generator_helper.h"

#include <sstream>
#include <string>
#include "paddle/fluid/framework/ir/fusion_group/operation.h"

namespace paddle {
namespace framework {
namespace ir {
namespace fusion_group {

template <typename T>
static T StringTo(const std::string& str) {
  std::istringstream is(str);
  T value;
  is >> value;
  return value;
}

static std::string ExpandMultivariateTemplate(const std::string& rhs,
                                              const size_t input_size) {
  int start_pos = rhs.find("[", 0);
  int end_pos = rhs.find("]", 0);
  std::string sum_rhs = rhs.substr(0, start_pos);
  std::string repeated_component =
      rhs.substr(start_pos + 1, (end_pos - start_pos - 1));
  int replace_pos = repeated_component.find("?", 0);

  for (size_t i = 1; i < input_size; i++) {
    std::string append_str = repeated_component;
    append_str.replace(replace_pos, 1, std::to_string(i));
    sum_rhs = sum_rhs + append_str;
  }
  return sum_rhs;
}

static std::string RefineTemplateWithAttr(const std::string& op_type,
                                          const std::string& exp_definition,
                                          const AttributeMap& attrs) {
  std::string ret;
  // here str_cvt convert string to number in some attr
  // for example in fill_constant str_value
  std::stringstream str_cvt;
  auto IsNumber = [exp_definition]() -> bool {
    return exp_definition.find_first_not_of("0123456789") == std::string::npos;
  };

  if (!IsNumber()) {
    // Get attr with different type, Now we only support the simple attr
    // condition
    std::string attr_name, default_value;
    if (exp_definition.find("=") != std::string::npos) {
      attr_name = exp_definition.substr(0, exp_definition.find("="));
      default_value = exp_definition.substr(exp_definition.rfind("=") + 1,
                                            exp_definition.length() - 1);
      ret = default_value;
    } else {
      attr_name = exp_definition;
    }
    auto it = attrs.find(attr_name);
    if (it == attrs.end()) {
      return ret;
    }
    Attribute attr = it->second;
    proto::AttrType attr_type =
        static_cast<proto::AttrType>(it->second.which() - 1);
    if (attr_type == proto::AttrType::BOOLEAN) {
      bool result = BOOST_GET(bool, attr);
      if (result) {
        ret = "true";
      } else {
        ret = "false";
      }
    } else if (attr_type == proto::AttrType::INT) {
      int result = BOOST_GET(int, attr);
      str_cvt << result;
      ret = str_cvt.str();
    } else if (attr_type == proto::AttrType::LONG) {
      int64_t result = BOOST_GET(int64_t, attr);
      str_cvt << result;
      ret = str_cvt.str();
    } else if (attr_type == proto::AttrType::FLOAT) {
      float result = BOOST_GET(float, attr);
      str_cvt << result;
      ret = str_cvt.str();
    } else if (attr_type == proto::AttrType::STRING) {
      std::string result = BOOST_GET(std::string, attr);
      ret = result;
    }
  } else {
    ret = exp_definition;
  }

  return ret;
}

std::string OperationExpression::GetRHS(std::unordered_set<int>* used,
                                        size_t exprs_index) const {
  auto rhs = OperationMap::Instance().Get(op_type_).exprs[exprs_index];
  auto num_operands = OperationMap::Instance().Get(op_type_).num_operands;

  if (num_operands == -1) {
    size_t input_size = input_ids_.size();
    rhs = ExpandMultivariateTemplate(rhs, input_size);
  }

  size_t pos = 0;
  while (pos < rhs.size()) {
    if (rhs[pos] == '$' && rhs[pos + 1] == '{') {
      size_t length = 0;
      int bracket_number = 1;
      for (length = 0; (pos + 2 + length) < rhs.size(); length++) {
        char ch = rhs[pos + 2 + length];
        if (ch == '}') bracket_number--;
        if (ch == '{') bracket_number++;
        if (bracket_number == 0) break;
      }
      std::string index_str = rhs.substr(pos + 2, length);
      std::string refine_str =
          RefineTemplateWithAttr(op_type_, index_str, attr_);
      std::string var_name;
      if (index_str == refine_str) {
        int index = StringTo<int>(index_str);
        PADDLE_ENFORCE_LT(index, input_ids_.size(),
                          platform::errors::InvalidArgument(
                              "Only %d inputs are provided, but need %d for "
                              "operation < %s >.",
                              input_ids_.size(), index + 1, op_type_));
        PADDLE_ENFORCE_GE(input_ids_[index], 0,
                          platform::errors::InvalidArgument(
                              "Expected %d-th input id > 0 for operation < %s "
                              ">. Received %d.",
                              index, op_type_, input_ids_[index]));
        var_name = TmpName(input_ids_[index]);
        rhs.replace(pos, length + 3, var_name);
        used->insert(input_ids_[index]);
      } else {
        var_name = refine_str;
        rhs.replace(pos, length + 3, var_name);
      }
      pos = pos + var_name.length();
    }
    pos++;
  }
  pos = 0;
  while (pos < rhs.size()) {
    if (rhs[pos] == '%' && rhs[pos + 1] == '{') {
      int length = 0;
      while (rhs[pos + 2 + length] != '}') {
        length++;
      }
      std::string number_str = rhs.substr(pos + 2, length);
      if (rhs_type_ == "__half")
        number_str = "__float2half(" + number_str + ")";
      rhs.replace(pos, length + 3, number_str);
      pos = pos + number_str.length();
    }
    pos++;
  }
  return rhs;
}

std::string OperationExpression::GetLHS(size_t i) const {
  std::stringstream ret;
  ret << lhs_type_ << " " << TmpName(output_ids_[i]);
  return ret.str();
}

bool OperationExpression::IsSupport() const {
  return OperationMap::Instance().Has(op_type_);
}

// we Traverse the graph and get the group , all input id and output id is
// unique for the node which belong the group
std::string OperationExpression::GetExpression(
    std::unordered_set<int>* used) const {
  std::stringstream ret;
  if (IsSupport()) {
    for (size_t i = 0; i < output_ids_.size(); ++i) {
      std::string cast_str = "";
      if (lhs_type_ == rhs_type_) {
        ret << GetLHS(i) << " = " << GetRHS(used, i) << ";";
      } else {
        if (lhs_type_ == "__half")
          cast_str = "__float2half";
        else if (rhs_type_ == "__half")
          cast_str = "__half2float";
        else
          cast_str = "static_cast<" + lhs_type_ + ">";
        ret << GetLHS(i) << " = " << cast_str << "(" << GetRHS(used, i) << ");";
      }
    }
  }
  return ret.str();
}

}  // namespace fusion_group
}  // namespace ir
}  // namespace framework
}  // namespace paddle
