artis-star/src/artis-star/common/event/Value.hpp

/**
 * @file common/event/Value.hpp
 * @author The ARTIS Development Team
 * See the AUTHORS or Authors.txt file
 */

/*
 * ARTIS - the multimodeling and simulation environment
 * This file is a part of the ARTIS environment
 *
 * Copyright (C) 2013-2022 ULCO http://www.univ-littoral.fr
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef COMMON_EVENT_VALUE
#define COMMON_EVENT_VALUE

#include <boost/serialization/serialization.hpp>

#include <any>
#include <memory>
#include <sstream>
#include <string>
#include <type_traits>
#include <valarray>
#include <vector>

namespace artis::common::event {

template<typename T>
struct HasToString {
  template<typename U, std::string (U::*)() const>
  struct SFINAE {
  };

  template<typename U>
  static char Test(SFINAE<U, &U::to_string> *);

  template<typename U>
  static int Test(...);

  static const bool Has = sizeof(Test<T>(0)) == sizeof(char);
};

class Value {

  class Base {
  public:
    virtual ~Base() = default;

    virtual bool operator==(const Base &other) const = 0;

    virtual std::string to_string() const = 0;

    virtual const std::type_info &type() const noexcept = 0;
  };

  template<typename T>
  class Data : public Base, public std::any {
  public:
    template<typename U = T, std::enable_if_t<not std::is_same_v<U, std::string>, bool> = true>
    Data(const U &value) : std::any(value) {}

    Data(const std::string &value) : std::any(value) {}

    Data(const std::valarray<T> &value) : std::any(value) {}

    Data(const std::vector<T> &value) : std::any(value) {}

    bool operator==(const Base &other) const override {
      return type() == other.type() and
             std::any_cast<const T &>(*this) == std::any_cast<const T &>(*dynamic_cast<const Data<T> *>(&other));
    }

    template<typename U>
    void operator()(U &value) const {
      value = std::any_cast<const U &>(*this);
    }

    std::string to_string() const override {
      std::stringstream ss;

      if constexpr (HasToString<T>::Has) {
        if (type() == typeid(std::vector<T>)) {
          const std::vector<T> &values = std::any_cast<const std::vector<T> &>(*this);

          for (const auto &e: values) {
            ss << std::boolalpha << e.to_string() << " ";
          }
        } else {
          ss << std::any_cast<const T &>(*this).to_string();
        }
      } else {
        if (type() == typeid(std::string)) {
          ss << std::any_cast<const std::string &>(*this);
        } else if (type() == typeid(std::valarray<T>)) {
          const std::valarray<T> &values = std::any_cast<const std::valarray<T> &>(*this);

          for (const auto &e: values) {
            ss << std::boolalpha << e << " ";
          }
        } else if (type() == typeid(std::vector<T>)) {
          const std::vector<T> &values = std::any_cast<const std::vector<T> &>(*this);

          for (const auto &e: values) {
            ss << std::boolalpha << e << " ";
          }
        } else {
          ss << std::boolalpha << std::any_cast<const T &>(*this);
        }
      }
      return ss.str();
    }

    const std::type_info &type() const noexcept override { return std::any::type(); }

  private:
    using _type = T;
  };

public:
  Value() : _data(nullptr) {}

  Value(const Value& value) : _data(value._data) {}

  template<typename T, std::enable_if_t<not HasToString<T>::Has, bool> = true>
  Value(const T &value) : _data(new Data<T>(value)) {}

  template<typename T>
  Value(const std::vector<T> &value) : _data(new Data<T>(value)) {}

  template<typename T, std::enable_if_t<HasToString<T>::Has, bool> = true>
  Value(const T &value) : _data(new Data<T>(value)) {}

  template<typename T, size_t size, std::enable_if_t<std::is_same<T, char>::value, bool> = true>
  Value(const T (&value)[size]) : _data(new Data<T>(std::string(value, size))) {}

  template<typename T>
  Value(const T *value, size_t size) : _data(new Data<T>(std::valarray<T>(value, size))) {}

  bool is_null() const { return _data.get() == nullptr; }

  template<typename Z>
  bool is_type() const { return _data->type() == typeid(Z); }

  Value& operator=(const Value &other) {
    _data = other._data;
    return *this;
  }

  bool operator==(const Value &other) const {
    return _data->operator==(*other._data);
  }

  template<typename T>
  void operator()(T &value) const {
    dynamic_cast<Data<T> *>(_data.get())->operator()(value);
  }

  template<typename T>
  void operator()(std::vector<T> &value) const {
    dynamic_cast<Data<T> *>(_data.get())->operator()(value);
  }

  template<typename T>
  void operator()(std::valarray<T> &value) const {
    dynamic_cast<Data<T> *>(_data.get())->operator()(value);
  }

  std::string to_string() const {
    return _data->to_string();
  }

private:
  friend class boost::serialization::access;

  template<typename Archive>
  void serialize(Archive &ar, const unsigned int version) {
    // TODO
  }

  std::shared_ptr<Base> _data;
};

std::ostream& operator<<(std::ostream& o, const artis::common::event::Value& value);

} // namespace artis common event

#endif