// Copyright (c) 2016-2018 Kiwano - Nomango
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#pragma once
#include <iomanip>
#include <sstream>
#include <kiwano/macros.h>
#include <kiwano/core/Common.h>

#ifndef KGE_SYS_LOG
#	ifdef KGE_DEBUG
#		define KGE_SYS_LOG(FORMAT, ...)	::kiwano::Logger::Instance().Printf(::kiwano::Logger::Level::System, FORMAT, __VA_ARGS__)
#	else
#		define KGE_SYS_LOG __noop
#	endif
#endif

#ifndef KGE_WARN
#	define KGE_WARN(FORMAT, ...)		::kiwano::Logger::Instance().Printf(::kiwano::Logger::Level::Warning, FORMAT, __VA_ARGS__)
#endif

#ifndef KGE_ERROR
#	define KGE_ERROR(FORMAT, ...)		::kiwano::Logger::Instance().Printf(::kiwano::Logger::Level::Error, FORMAT, __VA_ARGS__)
#endif

#ifndef KGE_LOG
#	define KGE_LOG(...)					::kiwano::Logger::Instance().Println(::kiwano::Logger::Level::Info, __VA_ARGS__)
#endif

#ifndef KGE_LOGF
#	define KGE_LOGF(FORMAT, ...)		::kiwano::Logger::Instance().Printf(::kiwano::Logger::Level::Info, FORMAT, __VA_ARGS__)
#endif

namespace kiwano
{
	/**
	* \~chinese
	* @brief 日志
	*/
	class KGE_API Logger
		: public Singleton<Logger>
	{
		friend Singleton<Logger>;

	public:
		/// \~chinese
		/// @brief 日志级别
		enum class Level
		{
			Info,		///< 信息
			System,		///< 系统
			Warning,	///< 警告
			Error		///< 错误
		};

		/// \~chinese
		/// @brief 输出流
		using OutputStream = std::wostream;

		/// \~chinese
		/// @brief 控制台颜色
		using ConsoleColor = Function<OutputStream& (OutputStream&)>;

		/// \~chinese
		/// @brief 打印日志
		/// @param level 日志级别
		/// @param format 格式字符串
		void Printf(Level level, const wchar_t* format, ...);

		/// \~chinese
		/// @brief 打印日志
		/// @param level 日志级别
		/// @param args 参数
		template <typename ..._Args>
		void Print(Level level, _Args&& ... args);

		/// \~chinese
		/// @brief 打印一行日志
		/// @param level 日志级别
		/// @param args 参数
		template <typename ..._Args>
		void Println(Level level, _Args&& ... args);

		/// \~chinese
		/// @brief 显示或关闭控制台
		/// @note 此操作会重置输出流
		void ShowConsole(bool show);

		/// \~chinese
		/// @brief 启用日志
		void Enable();

		/// \~chinese
		/// @brief 禁用日志
		void Disable();

		/// \~chinese
		/// @brief 获取输出流
		std::wostream& GetOutputStream();

		/// \~chinese
		/// @brief 获取错误流
		std::wostream& GetErrorStream();

		/// \~chinese
		/// @brief 重定向输出流
		std::wstreambuf* RedirectOutputStreamBuffer(std::wstreambuf* buf);

		/// \~chinese
		/// @brief 重定向错误流
		std::wstreambuf* RedirectErrorStreamBuffer(std::wstreambuf* buf);

		/// \~chinese
		/// @brief 重置输出流
		void ResetOutputStream();

	private:
		Logger();

		~Logger();

		void Prepare(Level level, StringStream& sstream);

		void Output(Level level, StringStream& sstream);

		void ResetConsoleColor() const;

		OutputStream& DefaultOutputColor(OutputStream& out);

	private:
		bool enabled_;
		WORD default_stdout_color_;
		WORD default_stderr_color_;

		OutputStream output_stream_;
		OutputStream error_stream_;
	};


	inline void Logger::Enable()
	{
		enabled_ = true;
	}

	inline void Logger::Disable()
	{
		enabled_ = false;
	}

	template <typename ..._Args>
	void Logger::Print(Level level, _Args&& ... args)
	{
		if (!enabled_)
			return;

		StringStream sstream;
		Prepare(level, sstream);

		// Format message
		(void)std::initializer_list<int>{((sstream << ' ' << args), 0)...};

		Output(level, sstream);
	}

	template <typename ..._Args>
	void Logger::Println(Level level, _Args&& ... args)
	{
		if (!enabled_)
			return;

		StringStream sstream;
		Prepare(level, sstream);

		// Format message
		(void)std::initializer_list<int>{((sstream << ' ' << args), 0)...};

		sstream << L"\r\n";

		Output(level, sstream);
	}

	inline void Logger::ResetConsoleColor() const
	{
		::SetConsoleTextAttribute(::GetStdHandle(STD_OUTPUT_HANDLE), default_stdout_color_);
		::SetConsoleTextAttribute(::GetStdHandle(STD_ERROR_HANDLE), default_stderr_color_);
	}

	inline Logger::OutputStream& Logger::DefaultOutputColor(OutputStream& out)
	{
		::SetConsoleTextAttribute(::GetStdHandle(STD_OUTPUT_HANDLE), default_stdout_color_);
		return out;
	}

	inline std::wostream& Logger::GetOutputStream()
	{
		return output_stream_;
	}

	inline std::wostream& Logger::GetErrorStream()
	{
		return error_stream_;
	}
}