// DRAGON.cpp: implementation of the DRAGON class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "PROGRAM1.h"
#include "DRAGON.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

DRAGON::DRAGON()
{
Init();
}

DRAGON::~DRAGON()
{

}

void DRAGON::Move()
{
	tail->rlink=first;
	first->llink=tail;
	first=tail;
	tail=tail->llink;
	tail->rlink=NULL;


}



DRAGON::DRAGONNODE::DRAGONNODE()
{
	x=0;
	y=0;
	llink=NULL;
	rlink=NULL;

}

void DRAGON::UpMove()
{
	tail->x=first->x;
	tail->y=first->y-Width;
	Move();

}

void DRAGON::DownMove()
{
	tail->x=first->x;
	tail->y=(first->y)+Width;
	Move();

}

void DRAGON::LeftMove()
{   
	tail->x=first->x-Width;
	tail->y=first->y;
	Move();

}

void DRAGON::RightMove()
{
	tail->x=first->x+Width;
	tail->y=first->y;
	Move();

}



int DRAGON::GetX(int nflag)
{
	DRAGONNODE *current=first;
	for(int i=0;i<nflag;i++)   if(current!=tail) current=current->rlink;
	return current->x;

}

int DRAGON::GetY(int nflag)
{
	
	DRAGONNODE *current=first;
	for(int i=0;i<nflag;i++)  if(current!=tail) current=current->rlink;
	return current->y;
}

void DRAGON::DgnMove()
{
	if(Direction==1) UpMove();
	if(Direction==2) DownMove();
	if(Direction==3) LeftMove();
	if(Direction==4) RightMove();
	

}



BOOL DRAGON::IsBody(int x, int y)
{
	for(int i=1;i<Lenth;i++)
		if(GetX(i)==x&&GetY(i)==y) return TRUE;
	return FALSE;

}


void DRAGON::Eat()
{
	DRAGONNODE *newnode=new DRAGONNODE;
	newnode->llink=tail;
	tail->rlink=newnode;
	if(GetX(Lenth)==GetX(Lenth-1))
	{
		newnode->x=tail->x;
		if(GetY(Lenth)>GetY(Lenth-1))	  newnode->y=tail->y+1; 
		else	                          newnode->y=tail->y-1; 
	}
	else if(GetY(Lenth)==GetY(Lenth-1))
	{
		newnode->y=tail->y;
		if(GetX(Lenth)>GetX(Lenth-1))	  newnode->y=tail->y+1;
		if(GetX(Lenth)>GetX(Lenth-1))	  newnode->y=tail->y+1;
	}
	tail=newnode;
	Lenth++;
}

void DRAGON::Init()
{
	tail=first=NULL;
	IsDead=FALSE;
	Direction=4;
	Lenth=6;
	Width=15;
	for(int i=0;i<Lenth;i++)
	{
		DRAGONNODE *newnode=new DRAGONNODE;
		newnode->x=Width+Width*i;
		newnode->y=Width;
		newnode->rlink=first;
		if(first!=NULL) first->llink=newnode;
		first=newnode;	if(newnode->rlink==NULL) tail=newnode;
		
	}

}