// snake.cpp

// 

// Copyright (c) 2009 - 2010 Accenture. All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

// 

// Initial Contributors:

// Accenture - Initial contribution

//

#include <fshell/ioutils.h>

#include <e32math.h>

using namespace IoUtils;

_LIT(KSnakeSeg, "*");

_LIT(KBait, "$");

class CKeyWatcher;

class CCmdSnake : public CCommandBase

	{

public:

	static CCommandBase* NewLC();

	~CCmdSnake();

	void Up();

	void Down();

	void Left();

	void Right();

	void Exit();

	void OnTimer();

private:

	CCmdSnake();

private: // From CCommandBase.

	virtual const TDesC& Name() const;

	virtual void DoRunL();

	virtual void ArgumentsL(RCommandArgumentList& aArguments);

	virtual void OptionsL(RCommandOptionList& aOptions);

	void ConstructL();

	void InitBoardL();

	void SetBoard(TInt aX, TInt aY, TBool aSet);

	TBool GetBoard(TInt aX, TInt aY);

	void DrawBoardL();

	void InitSnakeL(TInt aLen, TPoint aPos);

	void DrawSnakeL();

	void DrawScore();

	void PlaceBait();

	void Grow();

	void Dead();

private:

	RIoConsoleWriteHandle iCons;

	RIoConsoleReadHandle iConsIn;

	TSize iBoardSize;

	RArray<TPoint> iSnake;

	TInt iSnakeHead;

	RArray<TUint32> iBoard;

	TInt iBoardWidthWords;

	TPoint iDirection;

	TPoint iBait;

	TInt iScore;

	TInt iSpeed;

	CKeyWatcher* iKeys;

	CPeriodic* iTimer;

	TInt64 iRandomSeed;

	TBool iInCollisionGracePeriod;

	};

class CKeyWatcher : public CActive

	{

public:

	CKeyWatcher(CCmdSnake& aOwner, RIoConsoleReadHandle& aCons);

	~CKeyWatcher();

	void Request();

private:

	virtual void RunL();

	virtual void DoCancel();

private:

	CCmdSnake& iOwner;

	RIoConsoleReadHandle& iCons;

	};

CCommandBase* CCmdSnake::NewLC()

	{

	CCmdSnake* self = new(ELeave) CCmdSnake();

	CleanupStack::PushL(self);

	self->ConstructL();

	return self;

	}

CCmdSnake::~CCmdSnake()

	{

	delete iKeys;

	delete iTimer;

	iSnake.Close();

	iBoard.Close();

	}

CCmdSnake::CCmdSnake()

	: CCommandBase(EManualComplete), iSpeed(50000)

	{

	}

const TDesC& CCmdSnake::Name() const

	{

	_LIT(KName, "snake");	

	return KName;

	}

TInt OnTimerS(TAny* aSnake)

	{

	((CCmdSnake*)aSnake)->OnTimer();

	return KErrNone;

	}

void CCmdSnake::DoRunL()

	{

	if (!Stdout().AttachedToConsole())

		{

		LeaveIfErr(KErrNotSupported, _L("Stdout must be connected to a console"));

		}

	iCons = Stdout();

	if (!Stdin().AttachedToConsole())

		{

		LeaveIfErr(KErrNotSupported, _L("Stdin must be connected to a console"));

		}

	iConsIn = Stdin();

	iKeys = new(ELeave)CKeyWatcher(*this, iConsIn);

	iCons.SetCursorHeight(0);

	User::LeaveIfError(iCons.GetScreenSize(iBoardSize));

	iBoardSize.iHeight--; // space for status bar, plus to ensure that the console doesn't scroll when we draw the bottom line

	iBoardWidthWords = iBoardSize.iWidth / 32;

	if (iBoardSize.iWidth % 32) ++iBoardWidthWords;

	InitBoardL();

	DrawBoardL();

	TPoint centre;

	centre.iX = iBoardSize.iWidth / 2;

	centre.iY = iBoardSize.iHeight / 2;

	InitSnakeL(10, centre);	

	DrawSnakeL();

	PlaceBait();

	DrawScore();

	iTimer = CPeriodic::NewL(CActive::EPriorityStandard);

	iTimer->Start(iSpeed, iSpeed, TCallBack(OnTimerS, this));

	}

void CCmdSnake::ArgumentsL(RCommandArgumentList& /*aArguments*/)

	{

	}

void CCmdSnake::OptionsL(RCommandOptionList& aOptions)

	{

	_LIT(KOptSpeed, "speed");

	aOptions.AppendIntL(iSpeed, KOptSpeed);

	}

void CCmdSnake::ConstructL()

	{

	BaseConstructL();

	TTime now;

	now.HomeTime();

	iRandomSeed = now.Int64();

	}

void CCmdSnake::InitBoardL()

	{

	// first, zero the whole board

	iBoard.Reset();

	for (TInt y=0; y<iBoardSize.iHeight; ++y)

		{

		for (TInt x=0; x<iBoardWidthWords; ++x)

			{

			iBoard.AppendL(0);

			}

		}

	// draw a box around the edge

	for (TInt i=0; i<iBoardSize.iWidth; ++i)

		{

		SetBoard(i, 0, ETrue);

		SetBoard(i, iBoardSize.iHeight-1, ETrue);

		}

	for (TInt i=0; i<iBoardSize.iHeight; ++i)

		{

		SetBoard(0, i, ETrue);

		SetBoard(iBoardSize.iWidth-1, i, ETrue);

		}

	}

void CCmdSnake::SetBoard(TInt aX, TInt aY, TBool aSet)

	{

	TInt word = (aY * iBoardWidthWords) + (aX / 32);

	TInt bit = 1 << (aX % 32);

	if (aSet)

		{

		iBoard[word] |= bit;

		}

	else

		{

		iBoard[word] &= (~bit);

		}

	}

TBool CCmdSnake::GetBoard(TInt aX, TInt aY)

	{

	TInt word = (aY * iBoardWidthWords) + (aX / 32);

	TInt bit = 1 << (aX % 32);

	return iBoard[word] & bit;

	}

void CCmdSnake::DrawBoardL()

	{

	User::LeaveIfError(iCons.ClearScreen());

	RBuf line;

	line.CreateMaxL(iBoardSize.iWidth);

	CleanupClosePushL(line);

	for (TInt y=0; y<iBoardSize.iHeight; ++y)

		{

		for (TInt x=0; x<iBoardSize.iWidth; ++x)

			{

			}

		User::LeaveIfError(iCons.SetCursorPosAbs(TPoint(0, y)));

		User::LeaveIfError(iCons.Write(line));

		}

	CleanupStack::PopAndDestroy();

	}

void CCmdSnake::InitSnakeL(TInt aLen, TPoint aPos)

	{

	iSnake.Reset();

	for (TInt i=0; i<aLen; ++i)

		{

		iSnake.AppendL(aPos);

		}

	iSnakeHead = 0;

	}

void CCmdSnake::DrawSnakeL()

	{

	for (TInt i=0; i<iSnake.Count(); ++i)

		{

		User::LeaveIfError(iCons.SetCursorPosAbs(iSnake[i]));

		}

	}

void CCmdSnake::Up()

	{

	if (iDirection.iY != 1)

		{

		iDirection.SetXY(0, -1);

		}

	}

void CCmdSnake::Down()

	{

	if (iDirection.iY != -1)

		{

		iDirection.SetXY(0, 1);

		}

	}

void CCmdSnake::Left()

	{

	if (iDirection.iX != 1)

		{

		iDirection.SetXY(-1, 0);

		}

	}

void CCmdSnake::Right()

	{

	if (iDirection.iX != -1)

		{

		iDirection.SetXY(1, 0);

		}

	}

_LIT(KQuitFmt, "Quit; score: %d\n");

void CCmdSnake::Exit()

	{

	iCons.SetCursorPosAbs(TPoint(0, iBoardSize.iHeight));

	iCons.SetCursorHeight(20);

	TBuf<0x20> buf;

	buf.AppendFormat(KQuitFmt, iScore);

	iCons.Write(buf);

	Complete(iScore);

	}

_LIT(KDeadFmt, "Game over; score: %d\n");

void CCmdSnake::Dead()

	{

	iKeys->Cancel();

	iCons.SetCursorPosAbs(TPoint(0, iBoardSize.iHeight));

	iCons.SetCursorHeight(20);

	TBuf<0x20> buf;

	buf.AppendFormat(KDeadFmt, iScore);

	iCons.Write(buf);

	Complete(iScore);

	}

void CCmdSnake::OnTimer()

	{

	iKeys->Request();

	if (!(iDirection.iX || iDirection.iY)) return;

	TPoint newHead = iSnake[iSnakeHead] + iDirection + iBoardSize;

	newHead.iX %= iBoardSize.iWidth;

	newHead.iY %= iBoardSize.iHeight;

	// check for obstacles

	if (GetBoard(newHead.iX, newHead.iY))

		{

		if (iInCollisionGracePeriod)

			{

			Dead();

			}

		else

			{

			iInCollisionGracePeriod = ETrue;

			}

		return;

		}

	iInCollisionGracePeriod = EFalse;

	for (TInt i=0; i<iSnake.Count(); ++i)

		{

		if (newHead == iSnake[i])

			{

			Dead();

			return;

			}

		}

	TInt tail = (iSnakeHead+1) % iSnake.Count();

	// overwrite the tail if it's not in the same position as the segment before it

	if (iSnake[tail] != iSnake[(tail+1)%iSnake.Count()])

		{

		iCons.SetCursorPosAbs(iSnake[tail]);

		iCons.Write(_L(" "));

		}

	iCons.SetCursorPosAbs(newHead);

	iSnakeHead = (iSnakeHead+1) % iSnake.Count();

	iSnake[iSnakeHead] = newHead;

	if (iSnake[iSnakeHead] == iBait)

		{

		// Yummy!

		iScore++;

		DrawScore();

		PlaceBait();

		Grow();

		}

	}

_LIT(KScoreFormat, "Score: %d");

void CCmdSnake::DrawScore()

	{

	iCons.SetCursorPosAbs(TPoint(0, iBoardSize.iHeight));

	TBuf<0x20> score;

	score.AppendFormat(KScoreFormat, iScore);

	iCons.Write(score);

	}

void CCmdSnake::PlaceBait()

	{

	TBool ok;

	do

		{

		ok = ETrue;

		iBait.iX = Math::Rand(iRandomSeed) % iBoardSize.iWidth;

		iBait.iY = Math::Rand(iRandomSeed) % iBoardSize.iHeight;

		if (GetBoard(iBait.iX, iBait.iY)) ok = EFalse;

		if (ok)

			{

			for (TInt i=0; i<iSnake.Count(); ++i)

				{

				if (iSnake[i] == iBait) ok = EFalse;

				}

			}

		} while (!ok);

	iCons.SetCursorPosAbs(iBait);

	}

void CCmdSnake::Grow()

	{

	TInt tail = (iSnakeHead+1)% iSnake.Count();

	iSnake.Insert(iSnake[tail], tail);

	if (tail < iSnakeHead) iSnakeHead++;

	}

EXE_BOILER_PLATE(CCmdSnake)

//______________________________________________________________________________

//						CKeyWatcher

CKeyWatcher::CKeyWatcher(CCmdSnake& aOwner, RIoConsoleReadHandle& aCons)

	: CActive(EPriorityHigh), iOwner(aOwner), iCons(aCons)

	{

	CActiveScheduler::Add(this);

	Request();

	}

CKeyWatcher::~CKeyWatcher()

	{

	Cancel();

	}

void CKeyWatcher::RunL()

	{

	User::LeaveIfError(iStatus.Int());

	TKeyCode key = (TKeyCode)iCons.KeyCode();

	switch (key)

		{

	case EKeyUpArrow:

	case '2':

		iOwner.Up();

		break;

	case EKeyDownArrow:

	case '8':

		iOwner.Down();

		break;

	case EKeyLeftArrow:

	case '4':

		iOwner.Left();

		break;

	case EKeyRightArrow:

	case '6':

		iOwner.Right();

		break;

	case EKeyEscape:

	case EKeyBackspace:

		iOwner.Exit();

		break;

	default:

		break;

		}

	}

void CKeyWatcher::DoCancel()

	{

	iCons.WaitForKeyCancel();

	}

void CKeyWatcher::Request()