NBEngine/engine/NBCore/Logger.hpp

#pragma once
#ifndef _NB_LOGGER
#define _NB_LOGGER

#include <chrono>
#include <ostream>
#include <thread>
#include <unordered_map>
#include <vector>

#include "DataSink.hpp"
#include "Processes.hpp"
#include "ThreadSafeQueue.hpp"
#include "TypeTraits.hpp"

namespace nb {

template <typename T>
class ErrorBase;

typedef std::chrono::time_point<
    std::chrono::system_clock,
    std::chrono::nanoseconds
> LoggerTimePoint;

typedef std::string (*LogProcessFunction)(const LoggerTimePoint&, const std::string&);
typedef std::unordered_map<uint8_t, LogProcessFunction> LogProcessFunctionMap;

template<typename LogType, typename Logger, typename ST=std::ostream*>
class LoggerBase
: public MultithreadedDataProcessor<LogType, Logger>{
    using StreamType = ST;
    using LoggerType = Logger;
    using Base = MultithreadedDataProcessor<LogType, LoggerType>;
public:
    bool run() override {
        if (!static_cast<LoggerType*>(this)->isRunning()) {
            this->_running = true;
            this->_runningThread = std::make_shared<std::thread>([&]{
                while(static_cast<LoggerType*>(this)->isRunning()) {
                    static_cast<LoggerType*>(this)->flush();
                }
                static_cast<LoggerType*>(this)->flush();
            });
        }
        return static_cast<LoggerType*>(this)->isRunning();
    }
protected:
    LoggerBase() = default;

    StreamType _ostream;
};

struct LogEvent{
    const LoggerTimePoint time;
    const unsigned char lvl;
    const std::string msg;
    const std::thread::id tid;
    const uint64_t pid;
    const std::string file="";
    const unsigned int line=0;
};

template <typename LT>
class DebugLogger : public LoggerBase<LogEvent, LT, std::vector<std::ostream*>>{
    using StreamType = std::vector<std::ostream*>;
    using LoggerType = LT;
    using Base = LoggerBase<LogEvent, LoggerType, StreamType>;
public:

    template<typename... ST>
    DebugLogger(ST&... streams) : _ostream(nb::RefPackToPtrVec<std::ostream, ST...>(streams...).vec) {}

    ~DebugLogger() { static_cast<LoggerType*>(this)->stop(); }

    void log(
        std::string msg,
        uint8_t lvl=0x00,
        std::string file="",
        unsigned int line=0
    ) {
        static_cast<LoggerType*>(this)->push(LogEvent{
            std::chrono::system_clock::now(),
            lvl,
            msg,
            std::this_thread::get_id(),
            GetPID(),
            file,
            line
        });
    }

    template <size_t N>
    void log(
        char const(&msg) [N],
        uint8_t lvl=0x00,
        std::string file="",
        unsigned int line=0
    ) {
        static_cast<LoggerType*>(this)->log(std::string(msg), lvl, file, line);
    }

    template <typename T>
    void log(
        const ErrorBase<T>& err,
        uint8_t lvl=0xFF,
        std::string file="",
        unsigned int line=0
    ) {
        static_cast<LoggerType*>(this)->log(err.what(), lvl, file, line);
    }

    template <typename T>
    std::enable_if_t<std::is_base_of_v<std::exception, T>, void> log(
        const T& err,
        uint8_t lvl=0xFF,
        std::string file="",
        unsigned int line=0
    ) {
        static_cast<LoggerType*>(this)->log(std::string(err.what()), lvl, file, line);
    }

    template<typename U>
    void warn(
        U val,
        uint8_t lvl=0x01,
        std::string file="",
        unsigned int line=0
    ) { static_cast<LoggerType*>(this)->log(val, lvl, file, line); }

    template<typename U>
    void error(
        U val,
        std::string file="",
        unsigned int line=0
    ) {
        static_cast<LoggerType*>(this)->log(val, 0xFF, file, line);
        static_cast<LoggerType*>(this)->flush();
    }

protected:
    std::vector<std::ostream*> _ostream;

};

class DefaultDebugLogger : public DebugLogger<DefaultDebugLogger> {
    using LoggerType = DefaultDebugLogger;
    using Base = DebugLogger<DefaultDebugLogger>;
    
    template <typename... Ts>
    struct LogRow;

public:
    using Base::Base;

    ~DefaultDebugLogger() { stop(); }

    friend class BufferedDataProcessor<LogEvent, ThreadsafeQueue<LogEvent>, DefaultDebugLogger>;

    template <typename STR, typename... Ts>
    friend STR& operator<<(STR&, const DefaultDebugLogger::LogRow<Ts...>&);

protected:
    using Base::_ostream;

    bool process(const LogEvent& msg);
};  

#ifndef _NB_NO_LOGGER
extern DefaultDebugLogger logger;
#endif // _NB_NO_LOGGER

// Taking Charge of Adult ADHD by Russell Barkley

} // namespace nb

#endif // _NB_LOGGER