{-# LANGUAGE TupleSections #-}
{- Bullet update.  -}
module Dodge.Particle.Bullet.Update
    ( mvBullet
    ) where
import Dodge.Data
--import Dodge.Base
import Dodge.WorldEvent.ThingsHit
--import Picture
import Geometry
--import Geometry.Vector3D

import Data.Bifunctor
import Control.Lens
{-
Update for a generic bullet.
-}
mvBullet :: World -> Particle -> (World, Maybe Particle)
mvBullet w bt 
    | t <= 0 || magV (_btVel' bt) < 1 = wAnd Nothing
    | otherwise = second (fmap dodrag) $ hiteff bt (thingsHitExceptCr mcr p (p +.+ vel) w) w
  where 
    dodrag = btVel' %~ (drag *.*)
    drag = _btDrag bt
    wAnd    = (w,)
    mcr     = _btPassThrough' bt
    (p:_)  = _btTrail' bt
    vel     = _btVel' bt
    hiteff  = _btHitEffect' bt
    t       = _btTimer' bt