text: // Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
  // Distributed under the MIT License (http://opensource.org/licenses/MIT)
  
  #pragma once
  
  //
  // Custom sink for mongodb
  // Building and using requires mongocxx library.
  // For building mongocxx library check the url below
  // http://mongocxx.org/mongocxx-v3/installation/
  //
  
  #include "spdlog/common.h"
  #include "spdlog/details/log_msg.h"
  #include "spdlog/sinks/base_sink.h"
  #include <spdlog/details/synchronous_factory.h>
  
  #include <bsoncxx/builder/stream/document.hpp>
  #include <bsoncxx/types.hpp>
  #include <bsoncxx/view_or_value.hpp>
  
  #include <mongocxx/client.hpp>
  #include <mongocxx/instance.hpp>
  #include <mongocxx/uri.hpp>
  
  namespace spdlog {
  namespace sinks {
  template<typename Mutex>
  class mongo_sink : public base_sink<Mutex>
  {
  public:
      mongo_sink(const std::string &db_name, const std::string &collection_name, const std::string &uri = "mongodb://localhost:27017")
      {
          try
          {
              client_ = spdlog::details::make_unique<mongocxx::client>(mongocxx::uri{uri});
              db_name_ = db_name;
              coll_name_ = collection_name;
          }
          catch (const std::exception)
          {
              throw spdlog_ex("Error opening database");
          }
      }
  
      ~mongo_sink()
      {
          flush_();
      }
  
  protected:
      void sink_it_(const details::log_msg &msg) override
      {
          using bsoncxx::builder::stream::document;
          using bsoncxx::builder::stream::finalize;
  
          if (client_ != nullptr)
          {
              auto doc = document{} << "timestamp" << bsoncxx::types::b_date(msg.time) << "level" << level::to_string_view(msg.level).data()
                                    << "message" << std::string(msg.payload.begin(), msg.payload.end()) << "logger_name"
                                    << std::string(msg.logger_name.begin(), msg.logger_name.end()) << "thread_id"
                                    << static_cast<int>(msg.thread_id) << finalize;
              client_->database(db_name_).collection(coll_name_).insert_one(doc.view());
          }
      }
  
      void flush_() override {}
  
  private:
      static mongocxx::instance instance_;
      std::string db_name_;
      std::string coll_name_;
      std::unique_ptr<mongocxx::client> client_ = nullptr;
  };
  mongocxx::instance mongo_sink<std::mutex>::instance_{};
  
  #include "spdlog/details/null_mutex.h"
  #include <mutex>
  using mongo_sink_mt = mongo_sink<std::mutex>;
  using mongo_sink_st = mongo_sink<spdlog::details::null_mutex>;
  
  } // namespace sinks
  
  template<typename Factory = spdlog::synchronous_factory>
  inline std::shared_ptr<logger> mongo_logger_mt(const std::string &logger_name, const std::string &db_name,
      const std::string &collection_name, const std::string &uri = "mongodb://localhost:27017")
  {
      return Factory::template create<sinks::mongo_sink_mt>(logger_name, db_name, collection_name, uri);
  }
  
  template<typename Factory = spdlog::synchronous_factory>
  inline std::shared_ptr<logger> mongo_logger_st(const std::string &logger_name, const std::string &db_name,
      const std::string &collection_name, const std::string &uri = "mongodb://localhost:27017")
  {
      return Factory::template create<sinks::mongo_sink_st>(logger_name, db_name, collection_name, uri);
  }
  
  } // namespace spdlog
  