/******************************************************************************
 *                       ____    _    _____                                   *
 *                      / ___|  / \  |  ___|    C++                           *
 *                     | |     / _ \ | |_       Actor                         *
 *                     | |___ / ___ \|  _|      Framework                     *
 *                      \____/_/   \_|_|                                      *
 *                                                                            *
 * Copyright 2011-2019 Dominik Charousset                                     *
 *                                                                            *
 * Distributed under the terms and conditions of the BSD 3-Clause License or  *
 * (at your option) under the terms and conditions of the Boost Software      *
 * License 1.0. See accompanying files LICENSE and LICENSE_ALTERNATIVE.       *
 *                                                                            *
 * If you did not receive a copy of the license files, see                    *
 * http://opensource.org/licenses/BSD-3-Clause and                            *
 * http://www.boost.org/LICENSE_1_0.txt.                                      *
 ******************************************************************************/

#pragma once

#include "caf/fwd.hpp"
#include "caf/parser_state.hpp"

namespace caf {

/// Describes a field of `Object`.
template <class Object>
class config_value_field {
public:
  using object_type = Object;

  virtual ~config_value_field() = default;

  // -- observers --------------------------------------------------------------

  /// Returns whether this field has a default value.
  virtual bool has_default() const noexcept = 0;

  /// Returns the name of this field.
  virtual string_view name() const noexcept = 0;

  /// Returns the value of this field in `object` as config value.
  virtual config_value get(const Object& object) const = 0;

  /// Returns whether calling `set` with `x` would succeed.
  virtual bool valid_input(const config_value& x) const = 0;

  // -- modifiers --------------------------------------------------------------

  /// Tries to set this field in `object` to `x`.
  /// @returns `true` on success, `false` otherwise.
  virtual bool set(Object& object, const config_value& x) const = 0;

  /// Restores the default value for this field in `object`.
  /// @pre `has_default()`
  virtual void set_default(Object& object) const = 0;

  /// Parses the content for this field in `object` from `ps`.
  virtual void parse_cli(string_parser_state& ps, Object& object,
                         bool is_nested) const = 0;
};

} // namespace caf
