mongo_fetch.hpp

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/*
  __  __                         _____    _       _
 |  \/  | ___  _ __   __ _  ___ |  ___|__| |_ ___| |__
 | |\/| |/ _ \| '_ \ / _` |/ _ \| |_ / _ \ __/ __| '_ \
 | |  | | (_) | | | | (_| | (_) |  _|  __/ || (__| | | |
 |_|  |_|\___/|_| |_|\__, |\___/|_|  \___|\__\___|_| |_|
                     |___/
Paolo Bosetti, 2026
Fetches data from multiple MongoDB collections and prepare for replay by
merging them into a single view sorted by timestamp, also providing the time
difference between records.
*/
#pragma once
 
#include <chrono>
#include <memory>
#include <string>
#include <vector>
 
#include <nlohmann/json.hpp>
 
namespace Mads {
 
class MongoFetch {
public:
  explicit MongoFetch(const std::string &uri);
 
  ~MongoFetch();
 
  MongoFetch(const MongoFetch &) = delete;
  MongoFetch &operator=(const MongoFetch &) = delete;
  MongoFetch(MongoFetch &&) noexcept;
  MongoFetch &operator=(MongoFetch &&) noexcept;
 
  void connect();
 
  void disconnect();
 
  void select_database(const std::string &db_name);
 
  void select_collections(const std::vector<std::string> &collections);
 
  void select_time_range(const std::string &start, const std::string &end);
 
  void select_time_range(const std::string &start);
 
  std::size_t fetch_data();
 
  std::size_t fetch_data(std::string &view_name);
 
  std::size_t fetch_data(const std::string &view_name);
 
  std::size_t fetch_data_from(const std::string &view_name);
 
  void set_repeat(bool repeat);
 
  std::chrono::milliseconds load_next(nlohmann::json &out, std::string &collection_name);
 
  void set_unwrap_original(bool unwrap);
 
private:
  struct Impl;
  std::unique_ptr<Impl> _impl;
};
 
}  // namespace Mads