/*
 * utility_function.hpp
 *
 *  Created on: Jun 20, 2021
 *      Author: erki
 */

#ifndef SKULLC_UTILITY_FUNCTION_HPP_
#define SKULLC_UTILITY_FUNCTION_HPP_

namespace Utility
{

template<class>
class IFunction;

template<typename R, typename... Args>
class IFunction<R(Args...)>
{
public:
  using result_type = R;

  virtual ~IFunction()
  {}

  virtual result_type operator()(Args... args) = 0;
};

template<class>
class Function;

template<typename R, typename... Args>
class Function<R(Args...)> : public IFunction<R(Args...)>
{
public:
  using result_type = R;

  using signature = R (*)(Args...);

  Function() = delete;
  explicit Function(signature callable)
      : callable_(callable)
  {
    assert(callable_);
  }

  ~Function() override
  {
  }

  result_type operator()(Args... args) override
  {
    return (*callable_)(args...);
  }

private:
  signature callable_ = nullptr;
};

template<class, class>
class FunctionOwned;

template<typename H, typename R, typename... Args>
class FunctionOwned<H, R(Args...)> : public IFunction<R(Args...)>
{
public:
  using source = H;
  using result_type = R;

  using signature = R (source::*)(Args...);

  FunctionOwned() = delete;
  explicit FunctionOwned(source& src, signature callable)
      : src_(&src), callable_(callable)
  {
    assert(callable_);
  }

  ~FunctionOwned() override
  {}

  result_type operator()(Args... args) override
  {
    return (src_->*callable_)(args...);
  }

private:
  source* src_ = nullptr;
  signature callable_ = nullptr;
};

}// namespace Utility

#endif /* SKULLC_UTILITY_FUNCTION_HPP_ */