/******************************************************************************************
*	Chili Direct3D Engine																  *
*	Copyright 2018 PlanetChili <http://www.planetchili.net>								  *
*																						  *
*	This file is part of Chili Direct3D Engine.											  *
*																						  *
*	Chili Direct3D Engine is free software: you can redistribute it and/or modify		  *
*	it under the terms of the GNU General Public License as published by				  *
*	the Free Software Foundation, either version 3 of the License, or					  *
*	(at your option) any later version.													  *
*																						  *
*	The Chili Direct3D Engine is distributed in the hope that it will be useful,		  *
*	but WITHOUT ANY WARRANTY; without even the implied warranty of						  *
*	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the						  *
*	GNU General Public License for more details.										  *
*																						  *
*	You should have received a copy of the GNU General Public License					  *
*	along with The Chili Direct3D Engine.  If not, see <http://www.gnu.org/licenses/>.    *
******************************************************************************************/
#pragma once
#include <queue>
#include <bitset>

class Keyboard
{
	friend class Window;
public:
	class Event
	{
	public:
		enum class Type
		{
			Press,
			Release,
			Invalid
		};
	private:
		Type type;
		unsigned char code;
	public:
		Event() noexcept
			:
			type( Type::Invalid ),
			code( 0u )
		{}
		Event( Type type,unsigned char code ) noexcept
			:
			type( type ),
			code( code )
		{}
		bool IsPress() const noexcept
		{
			return type == Type::Press;
		}
		bool IsRelease() const noexcept
		{
			return type == Type::Release;
		}
		bool IsValid() const noexcept
		{
			return type != Type::Invalid;
		}
		unsigned char GetCode() const noexcept
		{
			return code;
		}
	};
public:
	Keyboard() = default;
	// 单例设计
	Keyboard( const Keyboard& ) = delete;
	// 单例设计
	Keyboard& operator=( const Keyboard& ) = delete;

	// key event stuff
	// 根据bitset keystates中指定Key的状态
	bool KeyIsPressed( unsigned char keycode ) const noexcept;

	// 从keyBuffer队列中找到最前面的Event，取出并移出队列
	Event ReadKey() noexcept;

	// 检查keyBuffer队列是否为空
	bool KeyIsEmpty() const noexcept;

	// 重置keyBuffer队列
	void FlushKey() noexcept;

	// char event stuff
	// 从charBuff队列中找到最前面的Event，取出并移出队列
	char ReadChar() noexcept;

	// 检查charBuffer队列是否为空
	bool CharIsEmpty() const noexcept;

	// 重置charBuffer队列
	void FlushChar() noexcept;

	// 重置keyBuffer和charBuffer队列
	void Flush() noexcept;

	// autorepeat control
	void EnableAutorepeat() noexcept;
	void DisableAutorepeat() noexcept;
	bool AutorepeatIsEnabled() const noexcept;
private:
	void OnKeyPressed( unsigned char keycode ) noexcept;
	void OnKeyReleased( unsigned char keycode ) noexcept;
	void OnChar( char character ) noexcept;
	void ClearState() noexcept;
	template<typename T>
	static void TrimBuffer( std::queue<T>& buffer ) noexcept;
private:
	// Key的数量，Unsigned 256足够对应所有的Key
	static constexpr unsigned int nKeys = 256u;

	// 队列长度
	static constexpr unsigned int bufferSize = 16u;

	// Todo
	bool autorepeatEnabled = false;

	// 用于存放每个Key的状态，每个bit的值对应一个Key的状态
	std::bitset<nKeys> keystates;

	// 用于存放Key事件的队列
	std::queue<Event> keybuffer;

	// 用于存放Char的队列
	std::queue<char> charbuffer;
};