/*  This file is part of FediPotato.
 *  Copyright © 2020 tastytea <tastytea@tastytea.de>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, version 3.
 *
 *  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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef FEDIPOTATO_CONFIG_HPP
#define FEDIPOTATO_CONFIG_HPP

#include "directories.hpp"

#include <nlohmann/json.hpp>

#if __has_include(<filesystem>)
#    include <filesystem>
#else
#    include <experimental/filesystem>
#endif
#include <string>
#include <string_view>

namespace FediPotato
{

using json = nlohmann::json;
namespace fs = std::filesystem;
using std::string;
using std::string_view;

/*!
 *  @brief  Read and write the configuration.
 *
 *  @throw  std::runtime_error                Directory not found.
 *  @throw  std::filesystem::filesystem_error Could not create directory.
 *  @throw  std::ifstream::failure            Could not read from file.
 *  @throw  std::ofstream::failure            Could not write to file.
 *  @throw  nlohmann::detail::parse_error     Could not parse file.
 *  @throw  nlohmann::detail::type_error      Setting not found / Wrong type.
 *
 *  @since  0.1.0
 *
 *  @headerfile config.hpp FediPotato/config.hpp
 */
class Config
{
public:
    /*!
     *  @brief  Construct a Config object.
     *
     *  @param  application_name The name of your application.
     *  @param  filename         The filename to open.
     *
     *  @throw  std::runtime_error                Directory not found.
     *  @throw  std::filesystem::filesystem_error Could not create directory.
     *
     *  @since  0.1.0
     */
    explicit Config(const string_view application_name,
                    const string_view filename)
        : _filename{filename}
        , _filepath{Directories(application_name).config() /= filename}
    {
        read();
    }

    //! Copy constructor
    Config(const Config &other) = default;

    //! Move constructor
    Config(Config &&other) noexcept = default;

    //! Destructor
    virtual ~Config() noexcept = default;

    //! Copy assignment operator
    Config& operator=(const Config &other) = delete;

    //! Move assignment operator
    Config& operator=(Config &&other) noexcept = delete;

public:
    /*!
     *  @brief  Read and parse the configuration from file.
     *
     *  @throw  std::ifstream::failure        Could not read from file.
     *  @throw  nlohmann::detail::parse_error Could not parse file.
     *
     *  @since  0.1.0
     */
    void read();

    /*!
     *  @brief  Write configuration to file.
     *
     *  @since  0.1.0
     */
    void write() const;

    /*!
     *  @brief  Set a configuration setting.
     *
     *  @param  key   The key of the setting.
     *  @param  value The value of the setting.
     *
     *  @throw  std::ofstream::failure Could not write to file.
     *
     *  @since  0.1.0
     */
    inline void set(const string_view key, const string_view value)
    {
        _configfile[key.data()] = value;
    }

    /*!
     *  @brief  Get a configuration setting.
     *
     *  @param  key The key of the setting.
     *
     *  @throw  nlohmann::detail::type_error Setting not found / Wrong type.
     *
     *  @since  0.1.0
     */
    [[nodiscard]]
    inline string get(const string_view key) const
    {
        return _configfile[key.data()].get<string>();
    }

private:
    const string _filename;
    const fs::path _filepath;
    json _configfile;
};

} // namespace FediPotato

#endif  // FEDIPOTATO_CONFIG_HPP