text: // Copyright (c) 2011-2016 The Skytells developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // @license MIT : http://www.opensource.org/licenses/mit-license.php.
  // @package Oxgram Cryptocurrency by Skytells, Inc.
  
  #pragma once
  
  #include <iostream>
  #include <type_traits>
  
  #include <boost/program_options/parsers.hpp>
  #include <boost/program_options/options_description.hpp>
  #include <boost/program_options/variables_map.hpp>
  
  namespace command_line
  {
    template<typename T, bool required = false>
    struct arg_descriptor;
  
    template<typename T>
    struct arg_descriptor<T, false>
    {
      typedef T value_type;
  
      const char* name;
      const char* description;
      T default_value;
      bool not_use_default;
    };
  
    template<typename T>
    struct arg_descriptor<std::vector<T>, false>
    {
      typedef std::vector<T> value_type;
  
      const char* name;
      const char* description;
    };
  
    template<typename T>
    struct arg_descriptor<T, true>
    {
      static_assert(!std::is_same<T, bool>::value, "Boolean switch can't be required");
  
      typedef T value_type;
  
      const char* name;
      const char* description;
    };
  
    template<typename T>
    boost::program_options::typed_value<T, char>* make_semantic(const arg_descriptor<T, true>& /*arg*/)
    {
      return boost::program_options::value<T>()->required();
    }
  
    template<typename T>
    boost::program_options::typed_value<T, char>* make_semantic(const arg_descriptor<T, false>& arg)
    {
      auto semantic = boost::program_options::value<T>();
      if (!arg.not_use_default)
        semantic->default_value(arg.default_value);
      return semantic;
    }
  
    template<typename T>
    boost::program_options::typed_value<T, char>* make_semantic(const arg_descriptor<T, false>& arg, const T& def)
    {
      auto semantic = boost::program_options::value<T>();
      if (!arg.not_use_default)
        semantic->default_value(def);
      return semantic;
    }
  
    template<typename T>
    boost::program_options::typed_value<std::vector<T>, char>* make_semantic(const arg_descriptor<std::vector<T>, false>& /*arg*/)
    {
      auto semantic = boost::program_options::value< std::vector<T> >();
      semantic->default_value(std::vector<T>(), "");
      return semantic;
    }
  
    template<typename T, bool required>
    void add_arg(boost::program_options::options_description& description, const arg_descriptor<T, required>& arg, bool unique = true)
    {
      if (unique && 0 != description.find_nothrow(arg.name, false))
      {
        std::cerr << "Argument already exists: " << arg.name << std::endl;
        return;
      }
  
      description.add_options()(arg.name, make_semantic(arg), arg.description);
    }
  
    template<typename T>
    void add_arg(boost::program_options::options_description& description, const arg_descriptor<T, false>& arg, const T& def, bool unique = true)
    {
      if (unique && 0 != description.find_nothrow(arg.name, false))
      {
        std::cerr << "Argument already exists: " << arg.name << std::endl;
        return;
      }
  
      description.add_options()(arg.name, make_semantic(arg, def), arg.description);
    }
  
    template<>
    inline void add_arg(boost::program_options::options_description& description, const arg_descriptor<bool, false>& arg, bool unique)
    {
      if (unique && 0 != description.find_nothrow(arg.name, false))
      {
        std::cerr << "Argument already exists: " << arg.name << std::endl;
        return;
      }
  
      description.add_options()(arg.name, boost::program_options::bool_switch(), arg.description);
    }
  
    template<typename charT>
    boost::program_options::basic_parsed_options<charT> parse_command_line(int argc, const charT* const argv[],
      const boost::program_options::options_description& desc, bool allow_unregistered = false)
    {
      auto parser = boost::program_options::command_line_parser(argc, argv);
      parser.options(desc);
      if (allow_unregistered)
      {
        parser.allow_unregistered();
      }
      return parser.run();
    }
  
    template<typename F>
    bool handle_error_helper(const boost::program_options::options_description& desc, F parser)
    {
      try
      {
        return parser();
      }
      catch (std::exception& e)
      {
        std::cerr << "Failed to parse arguments: " << e.what() << std::endl;
        std::cerr << desc << std::endl;
        return false;
      }
      catch (...)
      {
        std::cerr << "Failed to parse arguments: unknown exception" << std::endl;
        std::cerr << desc << std::endl;
        return false;
      }
    }
  
    template<typename T, bool required>
    bool has_arg(const boost::program_options::variables_map& vm, const arg_descriptor<T, required>& arg)
    {
      auto value = vm[arg.name];
      return !value.empty();
    }
  
  
    template<typename T, bool required>
    T get_arg(const boost::program_options::variables_map& vm, const arg_descriptor<T, required>& arg)
    {
      return vm[arg.name].template as<T>();
    }
   
    template<>
    inline bool has_arg<bool, false>(const boost::program_options::variables_map& vm, const arg_descriptor<bool, false>& arg)
    {
      return get_arg<bool, false>(vm, arg);
    }
  
  
    extern const arg_descriptor<bool> arg_help;
    extern const arg_descriptor<bool> arg_version;
    extern const arg_descriptor<std::string> arg_data_dir;
  }
  