#include <psemek/log/log.hpp>

#include <chrono>
#include <ctime>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <mutex>
#include <unordered_map>
#include <thread>

namespace psemek::log
{

	static int max_thread_name_length = 5;

	void set_max_thread_name_length(int length)
	{
		max_thread_name_length = length;
	}

	static std::unordered_map<std::thread::id, std::string> thread_names;

	void register_thread(std::string name)
	{
		register_thread(std::this_thread::get_id(), std::move(name));
	}

	void register_thread(std::thread::id id, std::string name)
	{
		auto it = thread_names.find(id);
		if (it != thread_names.end())
			throw std::runtime_error("Thread \"" + name + "\" already registered!");

		if (name.size() > max_thread_name_length)
			throw std::runtime_error("Thread \"" + name + "\" name is too long");

		thread_names[id] = name;

		put_message(level::info, "Thread \"" + name + "\" registered");
	}

	static ::tm safe_localtime(std::time_t const & time)
	{
		static std::mutex mutex;
		std::lock_guard lock{mutex};
		return *std::localtime(&time);
	}

	void put_message(level l, std::string const & message)
	{
		static std::string unknown_thread_name = "???";

		using clock = std::chrono::system_clock;

		auto const time = clock::to_time_t(clock::now());
		auto const tm = safe_localtime(time);

		auto const millis = std::chrono::duration_cast<std::chrono::milliseconds>(clock::now().time_since_epoch()).count() % 1000;

		auto const id = std::this_thread::get_id();
		auto const it = thread_names.find(id);

		auto const & thread_name = (it == thread_names.end()) ? unknown_thread_name : it->second;

		std::ostringstream os;
		os
			<< '[' << std::put_time(&tm, "%Y %b %d  %H:%M:%S.") << std::setw(3) << std::setfill('0') << millis << ']'
			<< '[' << std::setw(max_thread_name_length) << std::setfill(' ') << thread_name << ']'
			<< '[' << std::setw(7) << l << ']'
			<< ' ' << message;

		static std::mutex cout_mutex;
		std::lock_guard lock{cout_mutex};
		std::cout << os.str() << std::endl;
	}

}