module Dodge.Bullet where
import Dodge.Data
import Dodge.Creature.HandPos
import Dodge.Base.Coordinate
import Geometry
import LensHelp

import Data.Maybe
import Dodge.Movement.Turn
import Dodge.WorldEvent.ThingsHit

import Data.Bifunctor

updateBullet :: World -> Bullet -> (World,Maybe Bullet)
updateBullet w bu = case _buState bu of
    DyingBulletState -> (w,Nothing)
    DelayedBullet x -> mvBulletSlow x w bu
    _ -> mvBullet w bu

aBulAt
    :: Maybe Float    -- ^ Start velocity step factor
    -> Point2   -- ^ Start position
    -> Point2  -- ^ Velocity
    -> Float    -- ^ Drag
    -> HitEffect' 
    -> Float    -- ^ Bullet width
    -> BulletTrajectory
    -> Bullet
aBulAt vfact pos vel drag hiteff width butraj = Bullet
    { _buState = bulstate
    , _buUpdateMod = NoBulletUpdateMod
    , _buTrajectory = butraj
    , _buVel  = vel
    , _buDrag = drag
    , _buPos = pos
    , _buOldPos = pos
    , _buWidth = width
    , _buTimer = 100
    , _buHitEff = hiteff
    }
  where
    bulstate = maybe NormalBulletState DelayedBullet vfact

useAmmoParams :: Maybe Float -> Item -> Creature -> World -> World
useAmmoParams vfact it cr w = w & instantBullets .:~ aBulAt 
    vfact 
    sp
    (rotateV dir (muzvel *.* _amBulVel bultype))           -- vel
    (_rifling $ _itParams it)   -- drag
    (_amBulEff bultype) 
    (_amBulWth bultype) 
    thetraj
  where
    sp = _crPos cr +.+ (muzlength + 10) *.* unitVectorAtAngle dir
    dir = _crDir cr
    bultype = _laAmmoType $ _itConsumption it
    muzvel = _muzVel $ _itParams it
    muzlength = aimingMuzzlePos cr it
    thetraj = case _amBulTraj bultype of
        BasicBulletTrajectory -> BasicBulletTrajectory
        MagnetTrajectory{} -> fromMaybe BasicBulletTrajectory $ do
            tpos <- it ^? itTargeting . tgPos . _Just
            return $ MagnetTrajectory tpos
            --return $ \pt -> pt & buVel .+.+~ 5 *.* normalizeV (tpos -.- _buPos pt)
        FlechetteTrajectory{} -> fromMaybe BasicBulletTrajectory $ do
            tpos <- it ^? itTargeting . tgPos . _Just
            return $ FlechetteTrajectory tpos
            --return $ \pt -> pt & buVel %~ vecTurnTo 0.2 (_buPos pt) tpos
        BezierTrajectory{} -> fromMaybe BasicBulletTrajectory $ do
            tpos <- it ^? itTargeting . tgPos . _Just
            return $ BezierTrajectory sp tpos (mouseWorldPos w)
--            let bf t = bQuadToF (sp,mouseWorldPos w,tpos) $ (100 - t) * 0.05
--            return $ \pt -> pt 
--                & buVel .~ bf (fromIntegral $ _buTimer pt - 1) -.- bf (fromIntegral $ _buTimer pt)

{- 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