/*
==================================
=
= SelectDodgeDir
=
= Attempts to choose and initiate a movement for ob that sends it towards
= the player while dodging
=
= If there is no possible move (ob is totally surrounded)
=
= ob->dir			=	nodir
=
= Otherwise
=
= ob->dir			= new direction to follow
= ob->distance		= TILEGLOBAL or -doornumber
= ob->tilex			= new destination
= ob->tiley
= ob->areanumber    = the floor tile number (0-(NUMAREAS-1)) of destination
=
==================================
*/

void SelectDodgeDir (objtype *ob)
{
	int 		deltax,deltay,i;
	unsigned	absdx,absdy;
	dirtype 	dirtry[5];
	dirtype 	turnaround,tdir;

	if (ob->flags & FL_FIRSTATTACK)
	{
	//
	// turning around is only ok the very first time after noticing the
	// player
	//
		turnaround = nodir;
		ob->flags &= ~FL_FIRSTATTACK;
	}
	else
		turnaround=opposite[ob->dir];

	deltax = player->tilex - ob->tilex;
	deltay = player->tiley - ob->tiley;

//
// arange 5 direction choices in order of preference
// the four cardinal directions plus the diagonal straight towards
// the player
//

	if (deltax>0)
	{
		dirtry[1]= east;
		dirtry[3]= west;
	}
	else
	{
		dirtry[1]= west;
		dirtry[3]= east;
	}

	if (deltay>0)
	{
		dirtry[2]= south;
		dirtry[4]= north;
	}
	else
	{
		dirtry[2]= north;
		dirtry[4]= south;
	}

//
// randomize a bit for dodging
//
	absdx = abs(deltax);
	absdy = abs(deltay);

	if (absdx > absdy)
	{
		tdir = dirtry[1];
		dirtry[1] = dirtry[2];
		dirtry[2] = tdir;
		tdir = dirtry[3];
		dirtry[3] = dirtry[4];
		dirtry[4] = tdir;
	}

	if (US_RndT() < 128)
	{
		tdir = dirtry[1];
		dirtry[1] = dirtry[2];
		dirtry[2] = tdir;
		tdir = dirtry[3];
		dirtry[3] = dirtry[4];
		dirtry[4] = tdir;
	}

	dirtry[0] = diagonal [ dirtry[1] ] [ dirtry[2] ];

//
// try the directions util one works
//
	for (i=0;i<5;i++)
	{
		if ( dirtry[i] == nodir || dirtry[i] == turnaround)
			continue;

		ob->dir = dirtry[i];
		if (TryWalk(ob))
			return;
	}

//
// turn around only as a last resort
//
	if (turnaround != nodir)
	{
		ob->dir = turnaround;

		if (TryWalk(ob))
			return;
	}

	ob->dir = nodir;
}


/*
============================
=
= SelectChaseDir
=
= As SelectDodgeDir, but doesn't try to dodge
=
============================
*/

void SelectChaseDir (objtype *ob)
{
	int deltax,deltay,i;
	dirtype d[3];
	dirtype tdir, olddir, turnaround;


	olddir=ob->dir;
	turnaround=opposite[olddir];

	deltax=player->tilex - ob->tilex;
	deltay=player->tiley - ob->tiley;

	d[1]=nodir;
	d[2]=nodir;

	if (deltax>0)
		d[1]= east;
	else if (deltax<0)
		d[1]= west;
	if (deltay>0)
		d[2]=south;
	else if (deltay<0)
		d[2]=north;

	if (abs(deltay)>abs(deltax))
	{
		tdir=d[1];
		d[1]=d[2];
		d[2]=tdir;
	}

	if (d[1]==turnaround)
		d[1]=nodir;
	if (d[2]==turnaround)
		d[2]=nodir;


	if (d[1]!=nodir)
	{
		ob->dir=d[1];
		if (TryWalk(ob))
			return;     /*either moved forward or attacked*/
	}

	if (d[2]!=nodir)
	{
		ob->dir=d[2];
		if (TryWalk(ob))
			return;
	}

/* there is no direct path to the player, so pick another direction */

	if (olddir!=nodir)
	{
		ob->dir=olddir;
		if (TryWalk(ob))
			return;
	}

	if (US_RndT()>128) 	/*randomly determine direction of search*/
	{
		for (tdir=north;tdir<=west;tdir++)
		{
			if (tdir!=turnaround)
			{
				ob->dir=tdir;
				if ( TryWalk(ob) )
					return;
			}
		}
	}
	else
	{
		for (tdir=west;tdir>=north;tdir--)
		{
			if (tdir!=turnaround)
			{
			  ob->dir=tdir;
			  if ( TryWalk(ob) )
				return;
			}
		}
	}

	if (turnaround !=  nodir)
	{
		ob->dir=turnaround;
		if (ob->dir != nodir)
		{
			if ( TryWalk(ob) )
				return;
		}
	}

	ob->dir = nodir;		// can't move
}


/*
============================
=
= SelectRunDir
=
= Run Away from player
=
============================
*/

void SelectRunDir (objtype *ob)
{
	int deltax,deltay,i;
	dirtype d[3];
	dirtype tdir, olddir, turnaround;


	deltax=player->tilex - ob->tilex;
	deltay=player->tiley - ob->tiley;

	if (deltax<0)
		d[1]= east;
	else
		d[1]= west;
	if (deltay<0)
		d[2]=south;
	else
		d[2]=north;

	if (abs(deltay)>abs(deltax))
	{
		tdir=d[1];
		d[1]=d[2];
		d[2]=tdir;
	}

	ob->dir=d[1];
	if (TryWalk(ob))
		return;     /*either moved forward or attacked*/

	ob->dir=d[2];
	if (TryWalk(ob))
		return;

/* there is no direct path to the player, so pick another direction */

	if (US_RndT()>128) 	/*randomly determine direction of search*/
	{
		for (tdir=north;tdir<=west;tdir++)
		{
			ob->dir=tdir;
			if ( TryWalk(ob) )
				return;
		}
	}
	else
	{
		for (tdir=west;tdir>=north;tdir--)
		{
			ob->dir=tdir;
			if ( TryWalk(ob) )
			  return;
		}
	}

	ob->dir = nodir;		// can't move
}