/*
 * This file is part of smolbote. It's copyrighted by the contributors recorded
 * in the version control history of the file, available from its original
 * location: https://neueland.iserlohn-fortress.net/gitea/aqua/smolbote
 *
 * SPDX-License-Identifier: GPL-3.0
 */

#ifndef SMOLBOTE_CONFIGURATION_H
#define SMOLBOTE_CONFIGURATION_H

#include <QAction>
#include <QString>
#include <initializer_list>
#include <memory>
#include <optional>
#include <string>
#include <unordered_map>
#include <variant>
#include <vector>

#if defined(__clang__)
#define consumable(X) [[clang::consumable(X)]]
#define return_typestate(X) [[clang::return_typestate(X)]]
#define callable_when(X) [[clang::callable_when(X)]]
#define param_typestate(X) [[clang::param_typestate(X)]]
#else
#define consumable(X)
#define return_typestate(X)
#define callable_when(X)
#define param_typestate(X)
#endif

typedef std::variant<std::string, int, bool> conf_value_t;

class consumable(unconsumed) Configuration : private std::unordered_map<std::string, conf_value_t>
{
    friend std::ostream &operator<<(std::ostream &out, const Configuration &obj);

public:
    return_typestate(unconsumed) explicit Configuration();

    return_typestate(unconsumed) explicit Configuration(std::initializer_list<std::pair<std::string, conf_value_t>> l) noexcept;

    explicit Configuration(Configuration && other param_typestate(unconsumed)) = default;

    ~Configuration() = default;

    callable_when(unconsumed) void read(std::basic_istream<char> & input);

    template <typename T>
    callable_when(unconsumed) std::optional<T> value(const char *path) const
    {
        if(use_global)
            return instance()->value<T>(path);

        if(this->count(path) == 0) {
            return std::nullopt;
        }

        // path is guaranteed to exist
        const auto value = at(path);

        if constexpr(std::is_same_v<T, QString> || std::is_same_v<T, std::string>) {
            auto r = [&value]() {
                if(std::holds_alternative<std::string>(value))
                    return std::get<std::string>(value);
                else if(std::holds_alternative<int>(value))
                    return std::to_string(std::get<int>(value));
                else
                    return std::get<bool>(value) ? std::string("true") : std::string("false");
            }();

            if(r.front() == '~')
                r.replace(0, 1, m_homePath);

            if constexpr(std::is_same_v<T, QString>)
                return std::make_optional(QString::fromStdString(r));
            else
                return std::make_optional(r);

        } else if constexpr(std::is_same_v<T, QStringList>) {
            return std::make_optional(QString::fromStdString(std::get<std::string>(value)).split(';'));

        } else if(std::holds_alternative<T>(value)) {
            return std::optional<T>(std::get<T>(value));
        } else
            return std::nullopt;

    } // std::optional<T> value(path) const

    static void move_global(std::unique_ptr<Configuration> && conf);

private:
    static Configuration *instance();

    const std::string m_homePath;
    const bool use_global = false;
};

void setShortcut(QAction *action, const char *name);
std::ostream &operator<<(std::ostream &out, const Configuration &obj);

#endif // SMOLBOTE_CONFIGURATION_H