LXC/Common/IO.h

#pragma once

#include <OS.h>

#include <iostream>
#include <cstdlib>
#include <ostream>

namespace LXC::Internal
{
	// Returns a reference to the log file //
	// To be used only by LXC components //
	inline std::ofstream& Log()
	{
		static std::ofstream sLog;
		return sLog;
	}
}

namespace LXC::Util
{
	// Checks if a type can be outputted to std::ostream //
	template<typename T> concept Logable = requires(std::ostream& os, T t)
	{
		// I have no idea what this part does at all //
		{ os << t } -> std::same_as<std::ostream&>;
	};

	// Checks if a list of types can be outputted to std::ostream //
	template<typename... Args> concept AllLogable = (Logable<Args> && ...);

	// Checks if the type has a custom log method //
	template <typename T> concept HasLogStrFunc = requires(T obj)
	{
		// Checks the type has a function LogStr that returns a string //
		{ obj.LogStr() } -> std::same_as<std::string>;
	};

	// Enum to translate to the Win32 code for the colors //
	enum Color : WORD
	{
		BLACK			= 0x00,
		BLUE			= 0x01,
		GREEN			= 0x02,
		AQUA			= 0x03,
		RED				= 0x04,
		PURPLE			= 0x05,
		YELLOW			= 0x06,
		LIGHT_GRAY		= 0x07,
		LIGHT_BLUE		= 0x09,
		LIGHT_GREEN		= 0x0a,
		LIGHT_AQUA		= 0x0b,
		LIGHT_RED		= 0x0c,
		LIGHT_PURPLE	= 0x0d,
		LIGHT_YELLOW	= 0x0e,
		WHITE			= 0x0f
	};

	// Prints arguments to the console with the given color //
	template<Color col, typename... Args>
		requires AllLogable<Args...>
	inline void PrintAs(Args... args)
	{
		// Permenant handle to the console //
		static HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

		// Prints it to the console and resets the color //
		SetConsoleTextAttribute(hConsole, (WORD)col);
		(std::cout << ... << args);
		SetConsoleTextAttribute(hConsole, (WORD)Color::LIGHT_GRAY);
	}

	// Prints arguments to the console //
	template<typename... Args>
		requires AllLogable<Args...>
	inline void Print(Args... args)
	{
		// Fowards the arguments to the console //
		(std::cout << ... << args);
	}

	// Prints arguments to the console with a new-line character at the end //
	template<typename... Args>
		requires AllLogable<Args...>
	inline void PrintLn(Args... args)
	{
		// Fowards the arguments to the console //
		(std::cout << ... << args);
		std::cout << std::endl;
	}

	// Intitalises the log with the given file name //
	inline void CreateLog(const std::filesystem::path& path)
	{
		// Opens the log file with the given path //
		std::ofstream& log = Internal::Log();
		log.open(path);

		// Assigns a function to close the log file on program exit //
		std::atexit([]()
			{
				std::ofstream& log = Internal::Log();
				log.close();
			});
	}

	// Logs all the arguments to the file (automatically flushes) //
	template<typename... Args>
		requires AllLogable<Args...> && (sizeof...(Args) > 1)
	inline void Log(Args... args)
	{
		std::ofstream& log = Internal::Log();

		// Only attempts to write to an open log //
		if (log.is_open()) _UNLIKELY
		{
			// Opening symbol to make the log look fancy //
			log << "[LXC] \"";

			// Fowards the arguments to the log and flushes //
			(log << ... << args);
			log << "\"\n";
			log.flush();
		}
	}

	// Logs a singular argument to the log, calls Log() if it can on the object //
	template<typename T>
		requires HasLogStrFunc<T> || Logable<T>
	inline void Log(T arg)
	{
		std::ofstream& log = Internal::Log();

		// Only attempts to write to an open log //
		if (log.is_open()) _UNLIKELY
		{
			// Opening symbol to make log look fancy //
			log << "[LXC] ";
			
			// Logic if it can call LogStr() //
			if constexpr (HasLogStrFunc<T>)
			{
				// Prints the generated string //
				log << '{' << arg.LogStr() << "}\n";
				log.flush();
			}

			// Default logic //
			else
			{
				// Prints the singular arg //
				log << '"' << arg << "\"\n";
				log.flush();
			}
		}
	}
}