module Unit.Smart.Sniper ( Sniper(..)
                       , new
                       ) where

import Data.WrapAround ( WP, WM, vectorRelation )
import Animation
    ( Audible(..),
      Animation(..),
      audioReferenceDistance,
      audioRolloffFactor )
import Graphics.Gloss.Data.Picture
    ( Picture(Color, Rotate, Scale, Text) )
import Graphics.Gloss.Data.Color ( white )
import GHC.Float ( double2Float )
import Math ( radToDeg, vectorDirection, targetingA, subV )
import ResourceTracker ( ResourceTracker, getImage, getSound )
import Updating
    ( Observant(..), Transient(..), InternallyUpdating(..) )
import qualified Moving as M
    ( Colliding(..),
      Moving(..),
      Locatable(..),
      newVelocity,
      newLocation )
import Combat
    ( Launcher(..), Damageable(..), Damaging(..), Projectile(..) )
import qualified Projectile.BulletSII as P.BulletSII ( speed, new )
import AfterEffect ( AfterEffect(AfterEffect) )
import qualified AfterEffect.SimpleExplosion as SimpleExplosion
    ( new )
import Data.Maybe ( isNothing, fromMaybe, fromJust )
import Universe ( Arena(lance) )
import qualified Universe as U ( Arena(wrapMap) )
import Sound.ALUT
    ( Vertex3(Vertex3),
      HasSetter(($=)),
      SourceRelative(Listener),
      Source,
      ObjectName(genObjectNames),
      stop,
      sourceRelative,
      sourcePosition,
      rolloffFactor,
      referenceDistance,
      play,
      buffer )
import Common ( Velocity, Angle, Time )

radialVelocity = pi/6 -- radians per second

maxVelocityMag = 20

kamikazeDamage = 2.0

maxIntegrity = 1

accelerationRate = 30

adjAngle = pi / 8

shotDelay = 4.0

data Sniper = Sniper { angle :: Angle -- radians
                     , velocity :: Velocity
                     , center :: WP
                     , idealTargetLocation :: Maybe WP
                     , wrapMap :: WM
                     , launchTube :: [Projectile]
                     , sinceLastShot :: Time
                     , integrity :: Double
                     , vision :: Maybe Arena
                     , resourceTracker :: ResourceTracker
    
                     -- Sound
                     , queueShotSound :: Bool
                     , shotSoundSource :: Maybe Source
                     }

instance Audible Sniper where

  processAudio self lcenter =
    do self' <- if isNothing (shotSoundSource self)
                  then initializeShotSoundSource self
                  else return self
       if not (queueShotSound self)
               then return self'
               else do let (x, y) = vectorRelation
                                      (wrapMap self)
                                      (lcenter)
                                      (center self)
                       let s = fromJust $ shotSoundSource self
                       sourcePosition s $= (Vertex3 (double2Float x)
                                                    (double2Float (-y))
                                                    0)
                       play [s]
                       return self' { queueShotSound = False }

  terminateAudio self =
    if isNothing (shotSoundSource self)
      then return self
      else do stop [fromJust (shotSoundSource self)]
              return self

initializeShotSoundSource self =
  do [source] <- genObjectNames 1
     buffer source $= getSound (resourceTracker self) "energy-shot-02.wav"
     -- ...
     sourceRelative source $= Listener
     referenceDistance source $= audioReferenceDistance
--     maxDistance source $= audioMaxDistance
     rolloffFactor source $= audioRolloffFactor
     return self { shotSoundSource = Just source }

new :: ResourceTracker
        -> WM
        -> WP
        -> Angle
        -> Sniper
new rt wmap center' angle' =
  Sniper { center = center'
         , angle = angle'
         , idealTargetLocation = Nothing
         , velocity = (0.0, 0.0)
         , wrapMap = wmap
         , launchTube = []
         , sinceLastShot = 0.0
         , integrity = maxIntegrity
         , vision = Nothing
         , resourceTracker = rt

         , queueShotSound = False
         , shotSoundSource = Nothing
         }

instance Observant Sniper where

  updateVision self arena = self { vision = Just arena }

updateAngle t self
 = case vision self of
     Nothing -> self
     Just arena -> if isNothing (lance arena)
                     then self
                     else let sDir = vectorDirection (velocity self) in
                          let tDir = vectorDirection
                                       (vectorRelation
                                         (U.wrapMap arena)
                                         (center self)
                                         (M.center (fromJust (lance arena)))) in
                          let adj
                                | tDir - sDir > adjAngle = radialVelocity * t
                                | tDir -sDir < (-1) * adjAngle = (-radialVelocity) * t
                                | otherwise = 0.0 in
                          self { angle = angle self + adj }

updateVelocity :: Time -> Sniper -> Sniper
updateVelocity t self =
  self { velocity = M.newVelocity
                      (velocity self)
                      accelerationRate
                      (angle self)
                      maxVelocityMag
                      t                               
       }

instance Animation Sniper where
  image self _ = Rotate (double2Float
                          (radToDeg
                            (angle self)) * (-1) - 90)
                              pic
    where pic = fromMaybe
                 (Scale 0.20 0.20
                    (Color white
                    (Text "Error! Missing image!")))
                  (getImage rt "sniper.bmp")
          rt = resourceTracker self

instance M.Locatable Sniper where
  center = center

instance M.Moving Sniper where
  velocity = velocity

instance M.Colliding Sniper where
  collisionRadius _ = 20.0

instance InternallyUpdating Sniper where

  preUpdate self t = (updateFiringInformation t
                        . updateIdealTargetLocation t
                        . updateVelocity t
                        . updateAngle t) self

  postUpdate self t =
    let center' = fromMaybe (center self) (idealTargetLocation self) in
    self { center = center'
         , idealTargetLocation = Nothing
         }

updateFiringInformation t self =
  let sinceLastShot' = sinceLastShot self + t in
    if sinceLastShot' >= shotDelay
      then self { sinceLastShot = 0.0
                , launchTube = projectile : launchTube self
                , queueShotSound = True
                }
      else self { sinceLastShot = sinceLastShot' }
  where projectile = Projectile
                       (P.BulletSII.new
                         (wrapMap self)
                         pAngle
                         (center self)
                         (velocity self))
        pSpeed = P.BulletSII.speed
        pAngle = case vision self of
                   Nothing -> angle self
                   Just arena ->
                     case lance arena of
                       Nothing -> angle self
                       Just l -> targetingA
                                   pSpeed
                                   (vectorRelation
                                     (U.wrapMap arena)
                                     (center self)
                                     (M.center l))
                                   (subV
                                     (M.velocity l)
                                     (M.velocity self))

updateIdealTargetLocation :: Time -> Sniper -> Sniper
updateIdealTargetLocation t self =
  self { idealTargetLocation = Just (M.newLocation (wrapMap self)
                                                        (center self)
                                                        (velocity self)
                                                        t)
        }

instance Launcher Sniper where

  deployProjectiles self = (launchTube self, self { launchTube = [] })

instance Transient Sniper where

  expired' self = if integrity self > 0.0
                    then Nothing
                    else Just [aeffect]
    where aeffect = AfterEffect (SimpleExplosion.new (resourceTracker self)
                                                     (wrapMap self)
                                                     (center self)
                                                     (velocity self))

instance Damageable Sniper where

  inflictDamage self d = self { integrity = max 0.0 (integrity self - d) }

instance Damaging Sniper where

  damageEnergy self = kamikazeDamage