/*
 * This file is part of Quantum++.
 *
 * Copyright (c) 2013 - 2021 softwareQ Inc. All rights reserved.
 *
 * MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

/**
 * \file classes/idisplay.hpp
 * \brief Display interface via the non-virtual interface (NVI) and very basic
 * JSON serialization support interface
 */

#ifndef CLASSES_IDISPLAY_HPP_
#define CLASSES_IDISPLAY_HPP_

namespace qpp {
/**
 * \class qpp::IDisplay
 * \brief Abstract class (interface) that mandates the definition of
 * virtual std::ostream& display(std::ostream& os) const
 *
 * This class defines
 * friend std::ostream& operator<<(std::ostream& os, const qpp::IDisplay& rhs).
 * The latter delegates the work to the pure private virtual function
 * qpp::IDisplay::display() which has to be overridden by all derived classes.
 */
class IDisplay {
    /**
     * \brief Must be overridden by all derived classes
     *
     * The actual stream extraction processing is performed by the overridden
     * member function in the derived class. This function is automatically
     * invoked by
     * friend std::ostream& operator<<(std::ostream& os, const IDisplay& rhs).
     */
    virtual std::ostream& display(std::ostream& os) const = 0;

  public:
    /**
     * \brief Default virtual destructor
     */
    virtual ~IDisplay() = default;

    /**
     * \brief Overloads the extraction operator
     *
     * Delegates the work to the virtual function qpp::IDisplay::display()
     */
    friend std::ostream& operator<<(std::ostream& os, const IDisplay& rhs) {
        return rhs.display(os);
    }
}; /* class IDisplay */

/**
 * \class qpp::IJSON
 * \brief Abstract class (interface) that mandates the definition of
 * very basic JSON serialization support
 */
class IJSON {
  public:
    /**
     * \brief Default virtual destructor
     */
    virtual ~IJSON() = default;

    /**
     * \brief JSON representation of the derived instance, must be overridden by
     * all derived classes
     *
     * \param enclosed_in_curly_brackets If true, encloses the result in curly
     * brackets
     */
    virtual std::string
    to_JSON(bool enclosed_in_curly_brackets = true) const = 0;

}; /* class IJSON */

} /* namespace qpp */

#endif /* CLASSES_IDISPLAY_HPP_ */
