#ifndef GTL_LOGGER_H
#define GTL_LOGGER_H

#include <QThread>
#include <QObject>
#include <QDir>
#include <QTextStream>
#include <QFile>
#include "core_global.h"

namespace gtl
{

    enum class log_level {
        info,
        warning,
        error,
        debug
    };



    class CORE_EXPORT logger : public QObject
    {
        Q_OBJECT

        public:
            enum file_size_unit {
                b,
                kb,
                mb,
                gb
            };

            static logger *getInstance(void);
            static void init(const QString &path, const uint32_t max_file_size, const file_size_unit unit);
            static void info(const QString &tag, const QString &text);
            static void warning(const QString &tag, const QString &text);
            static void error(const QString &tag, const QString &text);
            static void debug(const QString &tag, const QString &text);

        private:
            static QFile _log_file;
            static QString _path;
            static QString _file_name;
            static QThread _thread;
            static uint32_t _max_file_size;
            static uint32_t _max_index;

            static void open_file(void);
            static QString find_last_file(void);
            static bool check_file_size(const QString& path);

        protected:
            logger(QObject *parent = nullptr);
            ~logger();

            bool _is_continue;
            static uint32_t get_file_size_unit(const file_size_unit unit);
            QString get_level_string(const log_level level);
            QString get_time_string(void);
            QString get_date_string(void);



        signals:
            void sgn_info(const QString &tag, const QString &text);
            void sgn_warning(const QString &tag, const QString &text);
            void sgn_error(const QString &tag, const QString &text);
            void sgn_debug(const QString &tag, const QString &text);
            void sgn_send_to_viewer(const QString &level, const QString &date, const QString &time, const QString &tag, const QString &text);


        public slots:
            void slt_info(const QString &tag, const QString &text)   { log(log_level::info, tag, text); }
            void slt_warning(const QString &tag, const QString &text){ log(log_level::warning, tag, text); }
            void slt_error(const QString &tag, const QString &text)  { log(log_level::error, tag, text); }
            void slt_debug(const QString &tag, const QString &text)  { log(log_level::debug, tag, text); }

            void log(log_level level = log_level::info, const QString &tag = "FLUSH", const QString &text = "flush")
            {
                QString s_level = get_level_string(level);
                QString s_date = get_date_string();
                QString s_time = get_time_string();

                QString str_new = "[" + s_level + "]::[" +\
                                  s_date + "]::[" +\
                                  s_time + "]::[" +\
                                  tag + "]::" +\
                                  text + "\n";

                QTextStream textStream(&_log_file);
                textStream << str_new.toStdString().c_str();

                if(false == check_file_size(_file_name))
                {
                    _max_index += 1;
                    _file_name = _path + QDir::separator() + "log_" + QString::number(_max_index).rightJustified(4, '0');

                    open_file();
                }

                emit sgn_send_to_viewer(s_level, s_date, s_time, tag, text);
            }
    };
}

#endif // GTL_LOGGER_H