MuditaOS/module-utils/i18/i18.hpp

/*
 *  @file i18.hpp
 *  @author Mateusz Piesta (mateusz.piesta@mudita.com)
 *  @date 29 mar 2019
 *  @brief I18 implementation
 *  @copyright Copyright (C) 2019 mudita.com
 *  @details
 */

#ifndef UNTITLED_I18_HPP
#define UNTITLED_I18_HPP

#include "json/json11.hpp"
#include <string>
#include "vfs.hpp"
#include "log/log.hpp"

#include "thread.hpp"

namespace utils
{

    enum class Lang
    {
        En,
        Pl,
        De,
        Sp
    };

    class LangLoader
    {

        const char *langEN_path = "sys/assets/lang/lang_en.json";
        const char *langPL_path = "sys/assets/lang/lang_pl.json";
        const char *langDE_path = "sys/assets/lang/lang_de.json";
        const char *langSP_path = "sys/assets/lang/lang_sp.json";

      public:
        LangLoader()
        {}
        virtual ~LangLoader()
        {}

        json11::Json Create(Lang lang)
        {
            std::string err;
            const char *path = nullptr;

            switch (lang) {
            case Lang::Pl:
                path = langPL_path;
                break;
            case Lang::En:
                path = langEN_path;
                break;
            case Lang::De:
                path = langDE_path;
                break;
            case Lang::Sp:
                path = langSP_path;
                break;

            default:
                return json11::Json();
            }

            auto fd = vfs.fopen(path, "r");
            if (fd == NULL) {
                LOG_FATAL("Error during opening file %s", path);
                return json11::Json();
            }

            uint32_t fsize = vfs.filelength(fd);

            char *stream = static_cast<char *>(malloc(fsize + 1)); // +1 for NULL terminator
            if (stream == NULL) {
                LOG_FATAL("Memory allocation failure");
                vfs.fclose(fd);
                return json11::Json();
            }

            memset(stream, 0, fsize + 1);

            vfs.fread(stream, 1, fsize, fd);

            json11::Json js = json11::Json::parse(stream, err);

            free(stream);
            vfs.fclose(fd);

            // Error
            if (err.length() != 0) {
                LOG_FATAL("%s", err.c_str());
                return json11::Json();
            }
            else {
                return js;
            }
        }
    };

    class i18
    {

        json11::Json langPack;
        json11::Json langBack; // backup language if item not found
        LangLoader loader;
        static const Lang lang_default = Lang::En;
        Lang current                   = lang_default;
        bool debugRequests             = true;

      public:
        // Default constructor, left empty on purpose
        i18()
        {}

        // Explicit initialization point, default constructor is omitted. This is because LangLoader uses file system
        // which is not available at program's startup.
        virtual ~i18()
        {}

        const std::string &get(const std::string &str)
        {
            auto retwithfallback = [this](const std::string &ret, const std::string &str) -> const std::string & {
                if (debugRequests && ret == "") {
                    return str;
                }
                else {
                    return ret;
                }
            };
            auto &ret = langPack[str].string_value();
            // if language pack returnet nothing then try default language
            if (ret == "" && current != lang_default) {
                auto &ret = langBack[str].string_value();
                return retwithfallback(ret, str);
            }
            return retwithfallback(ret, str);
        }

        void Switch(Lang lang)
        {
            static bool initialized = false;
            if (!initialized) {
                langBack    = loader.Create(lang_default);
                langPack    = langBack;
                initialized = true;
            }
            if (lang == current)
                return;
            current = lang;
            if (lang == lang_default) {
                langPack = langBack;
            }
            else {
                json11::Json pack = loader.Create(lang);
                // Suspend whole system during switching lang packs
                vTaskSuspendAll();
                langPack = pack;
                xTaskResumeAll();
            }
        }
    };

    // Global instance of i18 class
    extern i18 localize;
} // namespace utils

#endif // UNTITLED_I18_HPP