--{-# LANGUAGE TupleSections #-}
{- Bullet update.  -}
module Dodge.Particle.Bullet.Update
    ( mvBullet
    , mvBulletSlow
    , mvSpark
    ) where
import Dodge.Data
import Dodge.Movement.Turn
import Dodge.WorldEvent.ThingsHit
--import Picture
import Geometry
import LensHelp

import Data.Bifunctor
{- Update for a generic bullet.  -}
mvBullet :: World -> Bullet -> (World, Maybe Bullet)
mvBullet w bt' 
    | t <= 0 || magV (_buVel bt) < 1 = (w,Nothing)
    | otherwise = second (fmap dodrag) $ 
        hiteff bt (thingsHit p (p +.+ vel) w) w
  where
    bt = foldr (\mg b -> _mgField mg mg b) bt' $ _magnets w
    dodrag = case _buTrajectory bt of
        BasicBulletTrajectory -> buVel .*.*~ drag
        MagnetTrajectory tpos -> buVel .+.+~ 5 *.* normalizeV (tpos -.- _buPos bt)
        FlechetteTrajectory tpos -> buVel %~ vecTurnTo 0.2 (_buPos bt) tpos
        BezierTrajectory spos tpos xpos -> 
            let bf tm = bQuadToF (spos,xpos,tpos) $ (100 - tm) * 0.05
            in buVel .~ bf (fromIntegral $ _buTimer bt - 1) -.- bf (fromIntegral $ _buTimer bt)
    drag = _buDrag bt
    p       = _buPos bt
    vel     = _buVel bt
    hiteff  = _buHitEff bt
    t       = _buTimer bt

mvBulletSlow :: Float -> World -> Bullet -> (World, Maybe Bullet)
mvBulletSlow x w bt' 
    | t <= 0 || magV (_buVel bt) < 1 = (w,Nothing)
    | otherwise = second (fmap dodrag) $ 
        hiteff bt (thingsHit p (p +.+ vel) w) w
  where
    bt = foldr (\mg b -> _mgField mg mg b) bt' $ _magnets w
    dodrag = (buVel .*.*~ drag)
        . (buState .~ NormalBulletState)
    drag = _buDrag bt
    p       = _buPos bt
    vel     = x *.* _buVel bt
    hiteff  = _buHitEff bt
    t       = _buTimer bt

mvSpark :: World -> Particle -> (World, Maybe Particle)
mvSpark w bt' 
    | t <= 0 || magV (_ptVel bt) < 1 = (w,Nothing)
    | otherwise = second (fmap dodrag) $ 
        hiteff bt (thingsHit p (p +.+ vel) w) w
  where
    bt = bt'
    dodrag = ptVel .*.*~ drag
    drag = _ptDrag bt
    (p:_)   = _ptTrail bt
    vel     = _ptVel bt
    hiteff  = _ptHitEff bt
    t       = _ptTimer bt