/**
 * @file
 * @author  Caleb Fangmeier <caleb@fangmeier.tech>
 * @version 0.1
 *
 * @section LICENSE
 *
 *
 * MIT License
 *
 * Copyright (c) 2017 Caleb Fangmeier
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#ifndef root_dataset_h
#define root_dataset_h

#include <string>
#include <tuple>

#include "TChain.h"

#include "filval/filval.hpp"
#include "filval/root/filval.hpp"

using namespace std;
using namespace fv;
using namespace fv::util;
using namespace fv::root;

template<typename TREE_CLASS>
class TreeDataSet : public DataSet{
    private:
        // Maps filenames to data label, eg. "TTTT", or "TTZ"
        std::map<std::string,std::string> input_labels;
        // Maps filenames to data category. Either "signal" or "background"
        std::map<std::string,std::string> input_categories;
        std::string output_filename;
        std::map<std::string,DataFileDescriptor> file_descriptors;
        TFile* output_file;
        TREE_CLASS* tree_obj;
        long next_entry;
        long nentries;

        bool load_next(){
            if (next_entry >= nentries) return false;
            tree_obj->LoadTree(next_entry);
            tree_obj->GetEntry(next_entry);
            ++next_entry;
            return true;
        }

        int get_events(){
            return nentries;
        }

        int get_current_event(){
            return next_entry-1;
        }

        fv::util::DataFileDescriptor& get_current_file(){
            TFile* file = tree_obj->fChain->GetCurrentFile();
            std::string filename = file->GetName();
            return file_descriptors.at(filename);
        }

        /* void save_event_count(){ */
        /*     std::map<std::string,int> event_counts; */
        /*     std::map<std::string,float> xsecs; */
        /*     string fname, label; */
        /*     for(auto& p : input_labels){ */
        /*         std::tie(fname, label) = p; */
        /*         TFile f(fname.c_str()); */
        /*         TH1D* count = (TH1D*)f.Get("Count"); */
        /*         event_counts[label] = (int)count->GetBinContent(1); */

        /*         TTree* tree = (TTree*)f.Get("tree"); */
        /*         TBranch* b = tree->GetBranch("xsec"); */
        /*         float xsec; */
        /*         b->SetAddress(&xsec); */
        /*         b->GetEntry(1); */
        /*         xsecs[label] = xsec; */
        /*     } */
        /*     output_file->cd(); */
        /*     gDirectory->WriteObjectAny(&event_counts, "std::map<std::string,int>", "_event_counts"); */
        /*     gDirectory->WriteObjectAny(&xsecs, "std::map<std::string,float>", "_xsecs"); */
        /* } */

    public:

        TreeDataSet(const std::string& output_filename, const std::vector<DataFileDescriptor>& dfds,
                    const std::string& tree_name)
          :DataSet(),
           output_filename(output_filename),
           next_entry(0) {
            TChain* chain = new TChain(tree_name.c_str());
            int cnt = 0;
            for(const DataFileDescriptor& dfd : dfds){
                file_descriptors[dfd.filename] = dfd;
                /* file_descriptors.insert(std::make_pair(dfd.filename, dfd)); */
                /* file_descriptors.emplace(std::make_pair(dfd.filename, dfd)); */
                file_descriptors[dfd.filename].file_number = cnt++;
                chain->Add(dfd.filename.c_str());
                input_labels[dfd.filename] = dfd.label;
                input_categories[dfd.filename] = dfd.category;
            }
            tree_obj = new TREE_CLASS(chain);
            nentries = tree_obj->fChain->GetEntries();
            output_file = TFile::Open(output_filename.c_str(), "RECREATE");
            set_branch_status("*", false);
          }

        ~TreeDataSet(){
            /* save_event_count_and_xsection(); */
            output_file->Close();
        }

        const std::string& get_current_event_category() const{
            TFile* file = tree_obj->fChain->GetCurrentFile();
            std::string filename = file->GetName();
            return input_categories.at(filename);
        }

        const std::string& get_current_event_label() const{
            TFile* file = tree_obj->fChain->GetCurrentFile();
            std::string filename = file->GetName();
            return input_labels.at(filename);
        }

        template <typename T>
        Value<T>* track_branch(const std::string& bname){
            TBranch* branch = tree_obj->fChain->GetBranch(bname.c_str());
            if (branch == nullptr){
                CRITICAL("Branch: " << bname << " does not exist in input tree.", -1);
            }
            T* bref = (T*) branch->GetAddress();
            set_branch_status(bname, true);
            INFO("Registering branch \"" << bname
                 << "\" with address " << bref
                 << " and type " << typeid(bref).name());
            return new ObservedValue<T>(bname, bref);
        }

        template <typename T>
        Value<T*>* track_branch_ptr(const std::string& bname){
            TBranch* branch = tree_obj->fChain->GetBranch(bname.c_str());
            if (branch == nullptr){
                CRITICAL("Branch: " << bname << " does not exist in input tree.", -1);
            }
            T* bref = (T*) branch->GetAddress();
            set_branch_status(bname, true);
            INFO("Registering pointer branch \"" << bname
                 << "\" with address " << bref
                 << " and type " << typeid(bref).name());
            return new PointerValue<T>(bname, bref);
        }

        void set_branch_status(const std::string& bname, bool status){
            unsigned int found=0;
            tree_obj->fChain->SetBranchStatus(bname.c_str(), true, &found);
            if (!found){
                DataFileDescriptor& dfd = get_current_file();
                CRITICAL("Branch: " << bname << " does not exist in input tree of file "
                         << dfd.filename, -1);
            }

        }

        template <typename T>
        Value<T>* track_branch_obj(const std::string& bname){
            TBranch* branch = tree_obj->fChain->GetBranch(bname.c_str());
            if (branch == nullptr){
                CRITICAL("Branch: " << bname << " does not exist in input tree.", -1);
            }
            T** bref = (T**) branch->GetAddress();
            set_branch_status(bname, true);
            INFO("Registering object branch \"" << bname
                 << "\" with address " << bref
                 << " and type " << typeid(bref).name());
            return new ObjectValue<T>(bname, bref);
        }

        template <typename T>
        decltype(auto) track_branch_vec(const std::string& size_bname, const std::string& value_bname){
            track_branch_ptr<T>(value_bname);
            return wrapper_vector<T>(lookup<int>(size_bname), lookup<T*>(value_bname), value_bname);
        }

        void save_all(){
            output_file->cd();

            // Save the value names for each container to enable looking up
            // what values are plotted
            std::map<string,string> value_lookup = this->get_container_name_value_map();
            gDirectory->WriteObjectAny(&value_lookup, "std::map<std::string,std::string>", "_value_lookup");

            std::map<string,string> fn_impl_lookup = this->get_function_name_impl_map();
            gDirectory->WriteObjectAny(&fn_impl_lookup, "std::map<std::string,std::string>", "_function_impl_lookup");

            for(auto container : containers){
                container.second->save_as("outfile", SaveOption::ROOT);
            }
        }
};
#endif // root_dataset_h