config_manager.hpp

/**************************************************************************/
/* config_manager.hpp                                                     */
/**************************************************************************/
/*                         This file is part of:                          */
/*                                Knoodle                                 */
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#pragma once
 
#include <filesystem>
#include <optional>
#include <set>
#include <string>
#include <string_view>
#include <unordered_map>
#include "common.hpp"
#include "core_api.hpp"
 
namespace kn {
/**
 * Manages the configuration of the application.
 * The configuration is read from a file and stored in memory.
 */
class KN_CORE_API ConfigManager {
  ConfigManager() = default;
 
 public:
  ~ConfigManager() = default;
 
  static ConfigManager& get_instance();
 
  /**
   * Loads the configuration from a file and append it to the current configuration.
   * @param file_path The path to the file to load.
   * @return True if the file was successfully loaded, false otherwise.
   */
  bool load_config(const std::filesystem::path& file_path);
 
  /** Return a set of all the registered sections. */
  [[nodiscard]] std::set<std::string> get_sections() const;
 
  /**
   * Returns a value by key.
   * @param key The key to search for.
   * @return The value associated with the key, if it exists.
   */
  [[nodiscard]] std::optional<std::string> get_value(const std::string_view& key) const;
 
  /**
   * Returns a value by key as integer.
   * @param key The key to search for.
   * @return The value associated with the key, if it exists.
   */
  [[nodiscard]] std::optional<int32_t> get_int_value(const std::string_view& key) const;
 
  /**
   * Returns a value by key as real_t.
   * @param key The key to search for.
   * @return The value associated with the key, if it exists.
   */
  [[nodiscard]] std::optional<real_t> get_real_value(const std::string_view& key) const;
 
  /**
   * Returns a value by key as boolean.
   * @param key The key to search for.
   * @return The value associated with the key, if it exists.
   */
  [[nodiscard]] std::optional<bool> get_bool_value(const std::string_view& key) const;
 
 protected:
  /**
   * Parses a line from the configuration file.
   * @param line The line to parse.
   */
  virtual void parse_line(const std::string_view& line);
  /**
   * Parses a key-value pair from a line.
   * @param line The line to parse.
   */
  virtual void parse_key_value(const std::string_view& line);
  /**
   * Parses a comment from a line.
   * @param line The line to parse.
   */
  virtual void parse_comment(const std::string_view& line);
  /**
   * Parses a section from a line.
   * @param line The line to parse.
   */
  virtual void parse_section(const std::string_view& line);
  /**
   * Parses a blank line from a line.
   * @param line The line to parse.
   */
  virtual void parse_blank(const std::string_view& line);
  /**
   * Parses a line from the configuration file.
   * @param line The line to parse.
   */
 
 private:
  std::unordered_map<std::string, std::string> _config;
 
  std::string _current_section;
};
}  // namespace kn