#pragma once
#ifndef _NB_LOGGER
#define _NB_LOGGER

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

#include "Processes.hpp"
#include "ThreadSafeQueue.hpp"


namespace nb {

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

struct LogEvent{
    const LoggerTimePoint time;
    const unsigned char lvl;
    const std::string msg;
    const std::thread::id tid;
    const uint64_t pid;
};

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

template<typename LoggerName>
class Logger {
public:
    using Type = LoggerName;

    Logger(std::ostream& stream) : _ostream(&stream) {}

    bool isRunning() const {
        return _running && bool(_runningThread);
    }

    unsigned int count() const {
        return _queue.size();
    }
    
    bool run() {
        auto this_type = static_cast<Type*>(this);
        if (!isRunning()) {
            _runningThread = std::make_shared<std::thread>([&]{
                while(this_type->isRunning()) {
                    this_type->flush();
                }
            });
        }
        return isRunning();
    }

    bool stop() {
        if (isRunning()) {
            _running = false;
            _runningThread->join();
            _runningThread = nullptr;
            flush();
        }
        return isRunning();
    }

    LogEvent pop() {
        std::shared_ptr<LogEvent> event;
        _queue.pop(event);
        static_cast<Type*>(this)->process(*event);
        return *event;
    }
    
    void flush() {
        while(_queue.size()) {
            pop();
        }
    }
    
    void deleteAll() {
        _queue.empty();
    }

    template <typename T>
    void log(const T&, const uint8_t);

    void log(const std::string& msg, const uint8_t& lvl) {
        _queue.push(LogEvent{
            std::chrono::system_clock::now(),
            lvl,
            msg,
            std::this_thread::get_id(),
            get_pid(),
        });
    }

    void log(const std::exception& err, const uint8_t& lvl) {
        _queue.push(LogEvent{
            std::chrono::system_clock::now(),
            lvl,
            err.what(),
            std::this_thread::get_id(),
            get_pid(),
        });
    }

    void msg(const std::string& msg, const uint8_t& lvl=0x00) {
        static_cast<Type>(this)->log(msg, lvl);
    }

    void warn(const std::string& msg, const uint8_t& lvl=0x01) {
        static_cast<Type>(this)->log(msg, lvl);
    }
    void warn(const std::exception& err, const uint8_t lvl=0x01) {
        static_cast<Type>(this)->log(err, lvl);
    }

    void error(const std::string& msg, const uint8_t lvl=0xFF) {
        static_cast<Type>(this)->log(msg, lvl);
    }
    void error(const std::exception& err, const uint8_t lvl=0xFF) {
        static_cast<Type*>(this)->log(err, lvl);
    }

protected:
    void process(const LogEvent&);

    ThreadsafeQueue<LogEvent> _queue;
    std::ostream* const _ostream;
    std::atomic<bool> _running;
    std::shared_ptr<std::thread> _runningThread = nullptr;
};

class BasicLogger : public Logger<BasicLogger> {
public:
    using Base = Logger<BasicLogger>;
    BasicLogger(std::ostream& stream) : Base(stream) {}

    virtual void process(const LogEvent& event) {
        *_ostream << event.msg << "\n";
    }
};

} // namespace nb
#endif // _NB_LOGGER