/*
  *  MoMEMta: a modular implementation of the Matrix Element Method
  *  Copyright (C) 2016  Universite catholique de Louvain (UCL), Belgium
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation, either version 3 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <momemta/ParameterSet.h>
 #include <momemta/Module.h>
 #include <momemta/Types.h>
 #include <momemta/Utils.h>
 
 #include <stdexcept>
 
 template<typename T>
 class LinearCombinator: public Module {
     public:
 
         LinearCombinator(PoolPtr pool, const ParameterSet& parameters): Module(pool, parameters.getModuleName()) {
             auto tags = parameters.get<std::vector<InputTag>>("inputs");
             for (auto& v: tags)
                 m_terms.push_back(get<T>(v));
 
             m_coefficients = parameters.get<std::vector<double>>("coefficients");
 
             if (m_coefficients.size() == 0 || m_terms.size() == 0){
                 auto exception = std::invalid_argument("Tried to call LinearCombinator with an empty input.");
                 LOG(fatal) << exception.what();
                 throw exception;
             }
             if (m_coefficients.size() != m_terms.size()){
                 auto exception = std::invalid_argument("The Term and Coefficient lists passed to LinearCombinator have different sizes.");
                 LOG(fatal) << exception.what();
                 throw exception;
             }
         };
 
         virtual Status work() override {
 
             T temp_result = m_coefficients[0] * *m_terms[0];
             for (std::size_t i = 1; i < m_terms.size(); i++)
                 temp_result += m_coefficients[i] * *m_terms[i];
 
             *output = temp_result;
 
             return Status::OK;
         }
 
     private:
 
         // Inputs
         std::vector<double> m_coefficients;
         std::vector<Value<T>> m_terms;
 
         // Outputs
         std::shared_ptr<T> output = produce<T>("output");
 };
 
 REGISTER_MODULE_NAME("VectorLinearCombinator", LinearCombinator<LorentzVector>)
         .Inputs("inputs")
         .Output("output")
         .Attr("coefficients:list(double)");
 
 REGISTER_MODULE_NAME("DoubleLinearCombinator", LinearCombinator<double>)
         .Inputs("inputs")
         .Output("output")
         .Attr("coefficients:list(double)");
 
 REGISTER_MODULE_NAME("IntLinearCombinator", LinearCombinator<int64_t>)
         .Inputs("inputs")
         .Output("output")
         .Attr("coefficients:list(double)");