linux-wallpaperengine/src/WallpaperEngine/Data/JSON.h

#pragma once

#include <glm/detail/qualifier.hpp>
#include <glm/detail/type_vec1.hpp>
#include <nlohmann/json.hpp>
#include <optional>
#include <string>
#include <utility>

#include "WallpaperEngine/Data/Builders/UserSettingBuilder.h"
#include "WallpaperEngine/Data/Builders/VectorBuilder.h"
#include "WallpaperEngine/Data/Model/Types.h"
#include "WallpaperEngine/Data/Utils/SFINAE.h"
#include "WallpaperEngine/Logging/Log.h"

namespace WallpaperEngine::Data::JSON {
using namespace WallpaperEngine::Data::Builders;
using namespace WallpaperEngine::Data::Model;
using namespace WallpaperEngine::Data::Utils::SFINAE;

class JsonExtensions;

using JSON = nlohmann::basic_json<
    std::map,
    std::vector,
    std::string,
    bool,
    std::int64_t,
    std::uint64_t,
    double,
    std::allocator,
    nlohmann::adl_serializer,
    std::vector<std::uint8_t>,
    JsonExtensions
>;

/**
 * Small extensions class that is used as base class of nlohmann's implementation.
 *
 * Provides shorthand methods to reduce the amount of handling required for specific situations
 * (mainly throwing readable exceptions when a value is missing, optional/default values, user settings...)
 */
class JsonExtensions {
  public:
    using base_type = JSON;

    template <typename T, typename std::enable_if_t<is_glm_vec<T>::value, int> = 0>
    [[nodiscard]] T get () const {
        constexpr int length = GlmVecTraits<T>::length;
        constexpr glm::qualifier qualifier = GlmVecTraits<T>::qualifier;

        // call the specialized version of the function
        return get <length, typename GlmVecTraits<T>::type, qualifier> ();
    }
    template <int length, typename type, glm::qualifier qualifier>
    [[nodiscard]] glm::vec <length, type, qualifier> get () const {
        return VectorBuilder::parse <length, type, qualifier> (this->base ().get <std::string> ());
    }
    [[nodiscard]] base_type require (const std::string& key, const std::string& message) const {
        auto base  =  this->base ();
        auto it = base.find (key);

        if (it == base.end ()) {
            sLog.exception (message);
        }

        return *it;
    }
    template <typename T>
    [[nodiscard]] T require (const std::string& key, const std::string& message) const {
        auto base = this->base ();
        auto it = base.find (key);

        if (it == base.end ()) {
            sLog.exception (message);
        }

        return (*it);
    }
    [[nodiscard]] std::optional <base_type> optional (const std::string& key) const noexcept {
        auto base = this->base ();
        auto it = base.find (key);
        auto result = std::optional<base_type> {};

        if (it != base.end ()) {
            result.emplace (*it);
        }

        return result;
    }
    template <typename T>
    [[nodiscard]] std::optional <T> optional (const std::string& key) const noexcept {
        auto base = this->base ();
        auto it = base.find (key);

        if (it == base.end ()) {
            return std::nullopt;
        }

        return *it;
    }
    template <typename T>
    [[nodiscard]] T optional (const std::string& key, T defaultValue) const noexcept {
        auto base = this->base ();
        auto it = base.find (key);

        if (it == base.end ()) {
            return defaultValue;
        }

        return (*it);
    }
    [[nodiscard]] UserSettingUniquePtr user (const std::string& key, const Properties& properties) const;
    template <typename T>
    [[nodiscard]] UserSettingUniquePtr user (const std::string& key, const Properties& properties, T defaultValue) const {
        const auto value = this->optional (key);

        if (!value.has_value ()) {
            return UserSettingBuilder::fromValue <T> (defaultValue);
        }

        // performs a second lookup, but handles the actual call to UserSettingParser outside of this header
        // this resolving the include loop
        return this->user (key, properties);
    }

    template <int length, typename type, glm::qualifier qualifier>
    operator glm::vec <length, type, qualifier> () const {
        return get <length, type, qualifier> ();
    }
    template <typename T, typename std::enable_if_t<is_glm_vec<T>::value> = 0>
    operator T () const {
        constexpr int length = GlmVecTraits<T>::length;
        constexpr glm::qualifier qualifier = GlmVecTraits<T>::qualifier;

        // call the specialized version of the function
        return operator glm::vec <length, typename GlmVecTraits<T>::type, qualifier> ();
    }

  private:
    /**
     * @return The base json object to be used by the extension methods
     */
    [[nodiscard]] const base_type& base () const {
        return *static_cast<const base_type*> (this);
    }
};

} // namespace WallpaperEngine::Data::JSON