#include <functional>
#include <ios>
#include <nlohmann/json.hpp>

#include <filesystem>
#include <fstream>
#include <iostream>
#include <optional>
#include <string>
#include <unordered_map>
#include <vector>
#include <stdexcept>

namespace fs = std::filesystem;
using json   = nlohmann::json;

// ─────────────────────────────────────────────────────────────
//  Structure : nom d'instance décomposé depuis le nom de fichier
//  Format : Site_SiteCr_Tracks_Rames_Jobs_ID
// ─────────────────────────────────────────────────────────────

struct InstanceKey {
    int64_t site;
    int64_t site_cr;
    int64_t tracks;
    int64_t rames;
    int64_t jobs;
    int64_t id;
    std::string raw; // nom complet sans extension
    bool operator == (const InstanceKey& key) const
    {
        return key.raw == raw;
    }
};

struct HashInstanceKey
{
    size_t operator() (const InstanceKey& key) const{
        return std::hash<std::string>()(key.raw);
    }
};

InstanceKey parse_instance_name(const std::string& stem) {
    InstanceKey k;
    k.raw = stem;
    std::vector<int64_t> parts;
    std::string token;
    for (char c : stem) {
        if (c == '_') {
            if (!token.empty()) { parts.push_back(std::stoll(token)); token.clear(); }
        } else {
            token += c;
        }
    }
    if (!token.empty()) parts.push_back(std::stoll(token));

    if (parts.size() != 6)
        throw std::runtime_error("Nom d'instance invalide (attendu 6 entiers) : " + stem);

    k.site    = parts[0];
    k.site_cr = parts[1];
    k.tracks  = parts[2];
    k.rames   = parts[3];
    k.jobs    = parts[4];
    k.id      = parts[5];
    return k;
}

struct InstanceTradeOff{
    int64_t nbBranchBest;
    double timeRatio;
};

// ─────────────────────────────────────────────────────────────
//  Parse un fichier JSON et insère les résultats
// ─────────────────────────────────────────────────────────────

void process_file(const fs::path& path, std::unordered_map<InstanceKey, std::pair<unsigned int, double>, HashInstanceKey>& references, std::unordered_map<InstanceKey, std::optional<InstanceTradeOff>, HashInstanceKey>& trades) {
    // -- Nom d'instance depuis le stem du fichier
    InstanceKey key = parse_instance_name(path.stem().string());

    // -- Lecture JSON
    std::ifstream f(path);
    if (!f) throw std::runtime_error("Impossible d'ouvrir : " + path.string());

    json doc;
    try { f >> doc; }
    catch (const json::exception& e) {
        throw std::runtime_error("JSON invalide dans " + path.string() + " : " + e.what());
    }

    if (!doc.is_object())
        throw std::runtime_error("Le JSON doit être un objet à la racine : " + path.string());

    // -- Chaque clé = un algo
    for (auto& [algo_name, obj] : doc.items()) {
        if (!obj.is_object()) continue;

        if(algo_name == "rbs")
        {     
            int64_t     fct_obj   = obj.value("fctObjectif", int64_t{0});
            double      time_f    = obj.value("timeFinal",   0.0);
            references[key] = {
                fct_obj,
                time_f
            };
        }
        else
        {
            if(trades.find(key) != trades.end() && trades[key] != std::nullopt)
            {
                int64_t     fct_obj   = obj.value("fctObjectif", int64_t{0});
                int64_t     nbBranch   = obj.value("nbBranch", int64_t{0});

                double      time_f    = obj.value("timeFinal",   0.0);
                auto& tradePrec = trades[key];
                auto& ref = references[key];
                if(fct_obj <= ref.first && tradePrec->nbBranchBest > nbBranch)
                {
                    InstanceTradeOff tr = {
                        nbBranch,
                        time_f/ref.second
                    };
                    trades[key] = tr;
                }
            }
            else
            {
                int64_t     fct_obj   = obj.value("fctObjectif", int64_t{0});
                int64_t     nbBranch   = obj.value("nbBranch", int64_t{0});

                double      time_f    = obj.value("timeFinal",   0.0);

                auto& ref = references[key];
                if(fct_obj <= ref.first)
                {
                    InstanceTradeOff tr = {
                        nbBranch,
                        time_f/ref.second
                    };
                    trades[key] = tr;
                }
                else
                {
                    trades[key] = std::nullopt;
                }
            }
        }
    }
}

// ─────────────────────────────────────────────────────────────
//  Collecte récursive des .json dans un dossier
// ─────────────────────────────────────────────────────────────

std::vector<fs::path> collect_json_files(const fs::path& dir) {
    std::vector<fs::path> files;
    if (!fs::is_directory(dir)) {
        std::cerr << "[WARN] Pas un dossier, ignoré : " << dir << "\n";
        return files;
    }
    for (auto& entry : fs::recursive_directory_iterator(dir)) {
        if (entry.is_regular_file() && entry.path().extension() == ".json")
            files.push_back(entry.path());
    }
    return files;
}

void export_to_csv(std::unordered_map<InstanceKey, std::optional<InstanceTradeOff>, HashInstanceKey>& trades)
{
    std::ofstream oFile("export_tradeoff.csv", std::ios_base::out | std::ios_base::trunc);
    oFile << "Site;" << "SiteCr;" << "Tracks;" << "Rames;" << "Jobs;" << "ID;" << "NbBranch;" << "TimeRatio;\n";
    for(const auto& [ins, trade] : trades)
    {
        oFile << ins.site << ";" << ins.site_cr << ";" << ins.tracks << ";" << ins.rames << ";" << ins.jobs << ";" << ins.id << ";";
        if(trade)
        {
            oFile << trade->nbBranchBest << ";" << trade->timeRatio << ";\n";
        }
        else
        {
            oFile << -1 << ";" << -1 << ";\n";
        }
    }
    oFile.close();
}


// ─────────────────────────────────────────────────────────────
//  Main
// ─────────────────────────────────────────────────────────────

int main(int argc, char* argv[]) {
    if (argc < 2) {
        std::cerr << "Usage: " << argv[0] << " <dossier1> [dossier2 ...]\n";
        return 1;
    }

    std::vector<fs::path> dirs;
    for (int i = 1; i < argc; ++i) dirs.emplace_back(argv[i]);

    // -- Collecte des fichiers
    unsigned int all_files = 0;
    std::unordered_map<InstanceKey, std::optional<InstanceTradeOff>, HashInstanceKey> trades;
    std::unordered_map<InstanceKey, std::pair<unsigned int, double>, HashInstanceKey> reference;
    for (auto& d : dirs) {
        auto files = collect_json_files(d);
        all_files+= files.size();
        try {
            int ok = 0, err = 0;

            for (auto& path : files) {
                try {
                    process_file(path, reference, trades);
                    ++ok;
                    if (ok % 100 == 0)
                        std::cout << "  [" << ok << "/" << files.size() << "]\n";
                } catch (const std::exception& e) {
                    std::cerr << "[ERR] " << path.filename() << " : " << e.what() << "\n";
                    ++err;
                }
            }

            std::cout << "[DONE] " << ok << " ok, " << err << " erreur(s).\n";

        } catch (const std::exception& e) {
            std::cerr << "[ERR] " << e.what() << "\n";
            return 1;
        }
    }

    if (all_files == 0) {
        std::cerr << "[INFO] Aucun fichier .json trouvé.\n";
        return 0;
    }
    std::cout << "[INFO] " << all_files << " fichier(s) trouvé(s).\n";

    std::cout << "[INFO] " << "Exporting to CSV tradeoffs" << "\n";

    export_to_csv(trades);

    return 0;
}