/* Copyright (C) 2022 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Implements the in-game console with scripting support.
 */

#ifndef INCLUDED_CCONSOLE
#define INCLUDED_CCONSOLE

#include "lib/file/vfs/vfs_path.h"
#include "lib/input.h"

#include <deque>
#include <memory>
#include <mutex>
#include <string>

class CCanvas2D;
class CTextRenderer;

/**
 * In-game console.
 *
 * Thread-safety:
 * - Expected to be constructed/destructed in the main thread.
 * - InsertMessage may be called from any thread while the object is alive.
 */
class CConsole
{
	NONCOPYABLE(CConsole);

public:
	CConsole();
	~CConsole();

	void Init();

	void UpdateScreenSize(int w, int h);

	void ToggleVisible();
	void SetVisible(bool visible);

	/**
	 * @param deltaRealTime Elapsed real time since the last frame.
	 */
	void Update(const float deltaRealTime);

	void Render(CCanvas2D& canvas);

	void InsertChar(const int szChar, const wchar_t cooked);

	void InsertMessage(const std::string& message);

	void SetBuffer(const wchar_t* szMessage);

	// Only returns a pointer to the buffer; copy out of here if you want to keep it.
	const wchar_t* GetBuffer();
	void FlushBuffer();

	bool IsActive() const { return m_Visible; }

private:
	// Lock for all state modified by InsertMessage
	std::mutex m_Mutex;

	int m_FontHeight;
	int m_FontWidth;
	int m_FontOffset; // distance to move up before drawing
	size_t m_CharsPerPage;

	float m_X;
	float m_Y;
	float m_Height;
	float m_Width;

	// "position" in show/hide animation, how visible the console is (0..1).
	// allows implementing other animations than sliding, e.g. fading in/out.
	float m_VisibleFrac;

	std::deque<std::wstring> m_MsgHistory; // protected by m_Mutex
	std::deque<std::wstring> m_BufHistory;

	int m_MsgHistPos;

	std::unique_ptr<wchar_t[]> m_Buffer;
	int m_BufferPos;
	int m_BufferLength;

	VfsPath m_HistoryFile;
	int m_MaxHistoryLines;

	bool m_Visible;	// console is to be drawn
	bool m_Toggle;		// show/hide animation is currently active
	double m_PrevTime;	// the previous time the cursor draw state changed (used for blinking cursor)
	bool m_CursorVisState;	// if the cursor should be drawn or not
	bool m_QuitHotkeyWasShown;	// show console.toggle hotkey values at first time
	double m_CursorBlinkRate;	// cursor blink rate in seconds, if greater than 0.0

	void DrawWindow(CCanvas2D& canvas);
	void DrawHistory(CTextRenderer& textRenderer);
	void DrawBuffer(CTextRenderer& textRenderer);
	void DrawCursor(CTextRenderer& textRenderer);

	// Is end of Buffer?
	bool IsEOB() const;
	// Is beginning of Buffer?
	bool IsBOB() const;
	bool IsFull() const;
	bool IsEmpty() const;

	void ProcessBuffer(const wchar_t* szLine);

	void LoadHistory();
	void SaveHistory();
	void ShowQuitHotkeys();
};

extern CConsole* g_Console;

extern InReaction conInputHandler(const SDL_Event_* ev);

#endif // INCLUDED_CCONSOLE