#include "a_sharedglobal.h"
#include "p_local.h"
#include "g_level.h"


IMPLEMENT_CLASS(AFastProjectile)


//----------------------------------------------------------------------------
//
// AFastProjectile :: Tick
//
// Thinker for the ultra-fast projectiles used by Heretic and Hexen
//
//----------------------------------------------------------------------------

void AFastProjectile::Tick ()
{
	int i;
	fixed_t xfrac;
	fixed_t yfrac;
	fixed_t zfrac;
	int changexy;

	PrevX = x;
	PrevY = y;
	PrevZ = z;
	PrevAngle = angle;

	if (!(flags5 & MF5_NOTIMEFREEZE))
	{
		//Added by MC: Freeze mode.
		if (bglobal.freeze || level.flags2 & LEVEL2_FROZEN)
		{
			return;
		}
	}


	// [RH] Ripping is a little different than it was in Hexen
	FCheckPosition tm(!!(flags2 & MF2_RIP));

	int shift = 3;
	int count = 8;
	if (radius > 0)
	{
		while ( ((abs(velx) >> shift) > radius) || ((abs(vely) >> shift) > radius))
		{
			// we need to take smaller steps.
			shift++;
			count<<=1;
		}
	}

	// Handle movement
	if (velx || vely || (z != floorz) || velz)
	{
		xfrac = velx >> shift;
		yfrac = vely >> shift;
		zfrac = velz >> shift;
		changexy = xfrac || yfrac;
		int ripcount = count >> 3;
		for (i = 0; i < count; i++)
		{
			if (changexy)
			{
				if (--ripcount <= 0)
				{
					tm.LastRipped = NULL;	// [RH] Do rip damage each step, like Hexen
				}
				
				if (!P_TryMove (this, x + xfrac,y + yfrac, true, false, tm))
				{ // Blocked move
					P_ExplodeMissile (this, BlockingLine, BlockingMobj);
					return;
				}
			}
			z += zfrac;
			if (z <= floorz)
			{ // Hit the floor
				z = floorz;
				P_HitFloor (this);
				P_ExplodeMissile (this, NULL, NULL);
				return;
			}
			if (z + height > ceilingz)
			{ // Hit the ceiling
				z = ceilingz - height;
				P_ExplodeMissile (this, NULL, NULL);
				return;
			}
			if (changexy && ripcount <= 0) 
			{
				ripcount = count >> 3;
				Effect();
			}
		}
	}
	// Advance the state
	if (tics != -1)
	{
		if (tics > 0) tics--;
		while (!tics)
		{
			if (!SetState (state->GetNextState ()))
			{ // mobj was removed
				return;
			}
		}
	}
}


void AFastProjectile::Effect()
{
	//if (pr_smoke() < 128)	// [RH] I think it looks better if it's consistent
	{
		FName name = (ENamedName) this->GetClass()->Meta.GetMetaInt (ACMETA_MissileName, NAME_None);
		if (name != NAME_None)
		{
			fixed_t hitz = z-8*FRACUNIT;
			if (hitz < floorz)
			{
				hitz = floorz;
			}
		
			const PClass *trail = PClass::FindClass(name);
			if (trail != NULL)
			{
				AActor *act = Spawn (trail, x, y, hitz, ALLOW_REPLACE);
				if (act != NULL)
				{
					act->angle = this->angle;
				}
			}
		}
	}
}