content: {-# LANGUAGE TupleSections #-}
  -- | Screen frames and animations.
  module Game.LambdaHack.Client.UI.Animation
    ( Animation, renderAnim
    , pushAndDelay, twirlSplash, twirlSplashShort, blockHit, blockMiss, subtleHit
    , deathBody, shortDeathBody, actorX, teleport, vanish, swapPlaces, fadeout
  #ifdef EXPOSE_INTERNAL
      -- * Internal operations
    , blank, cSym, mapPosToOffset, mzipSingleton, mzipPairs
  #endif
    ) where
  
  import Prelude ()
  
  import Game.LambdaHack.Core.Prelude
  
  import           Data.Bits (xor)
  import qualified Data.EnumMap.Strict as EM
  import           Data.Word (Word32)
  
  import Game.LambdaHack.Client.UI.Content.Screen
  import Game.LambdaHack.Client.UI.Frame
  import Game.LambdaHack.Client.UI.Overlay
  import Game.LambdaHack.Client.UI.PointUI
  import Game.LambdaHack.Common.Point
  import Game.LambdaHack.Core.Random
  import Game.LambdaHack.Definition.Color
  
  -- | Animation is a list of frame modifications to play one by one,
  -- where each modification if a map from positions to level map symbols.
  newtype Animation = Animation [OverlaySpace]
    deriving (Show, Eq)
  
  -- | Render animations on top of a screen frame.
  --
  -- Located in this module to keep @Animation@ abstract.
  renderAnim :: Int -> PreFrame -> Animation -> PreFrames
  renderAnim width basicFrame (Animation anim) =
    let modifyFrame :: OverlaySpace -> PreFrame
        -- Overlay not truncated, because guaranteed within bounds.
        modifyFrame am = overlayFrame width am basicFrame
        modifyFrames :: OverlaySpace -> OverlaySpace -> Maybe PreFrame
        modifyFrames am amPrevious =
          if am == amPrevious then Nothing else Just $ modifyFrame am
    in Just basicFrame : zipWith modifyFrames anim ([] : anim)
  
  blank :: Maybe AttrCharW32
  blank = Nothing
  
  cSym :: Color -> Char -> Maybe AttrCharW32
  cSym color symbol = Just $ attrChar2ToW32 color symbol
  
  mapPosToOffset :: (Point, AttrCharW32) -> (PointUI, AttrString)
  mapPosToOffset (p, attr) =
    let pUI = squareToUI $ mapToSquare p
    in (pUI, [attr])
  
  mzipSingleton :: Point -> Maybe AttrCharW32 -> OverlaySpace
  mzipSingleton p1 mattr1 =
    map mapPosToOffset $
      let mzip (pos, mattr) = fmap (pos,) mattr
      in catMaybes [mzip (p1, mattr1)]
  
  mzipPairs :: (Point, Point) -> (Maybe AttrCharW32, Maybe AttrCharW32)
            -> OverlaySpace
  mzipPairs (p1, p2) (mattr1, mattr2) =
    map mapPosToOffset $
      let mzip (pos, mattr) = fmap (pos,) mattr
      in catMaybes $ if p1 /= p2
                     then [mzip (p1, mattr1), mzip (p2, mattr2)]
                     else -- If actor affects himself, show only the effect,
                          -- not the action.
                          [mzip (p1, mattr1)]
  
  -- | Empty animation with a frame of delay, to be used to momentarily display
  -- something for the player to see, e.g., the aiming line when swerving it.
  -- Don't use this if there are multi-line messages on the screen,
  -- because the text blinking is going to be distracting.
  pushAndDelay :: Animation
  pushAndDelay = Animation [[]]
  
  -- | Attack animation. A part of it also reused for self-damage and healing.
  twirlSplash :: (Point, Point) -> Color -> Color -> Animation
  twirlSplash poss c1 c2 = Animation $ map (mzipPairs poss)
    [ (blank           , cSym BrCyan '&')
    , (blank           , cSym BrCyan '&')
    , (blank           , blank)
    , (cSym c1      '\\',blank)
    , (cSym c1      '|', cSym BrCyan '&')
    , (cSym c1      '%', blank)
    , (cSym c1      '/', blank)
    , (cSym c1      '-', blank)
    , (cSym c1      '\\',blank)
    , (cSym c2      '|', blank)
    , (cSym c2      '%', blank)
    ]
  
  -- | Short attack animation.
  twirlSplashShort :: (Point, Point) -> Color -> Color -> Animation
  twirlSplashShort poss c1 c2 = Animation $ map (mzipPairs poss)
    [ (blank           , cSym BrCyan '&')
    , (blank           , cSym BrCyan '&')
    , (cSym c1      '\\',blank)
    , (cSym c1      '|', cSym BrCyan '&')
    , (cSym c2      '%', blank)
    ]
  
  -- | Attack that hits through a block.
  blockHit :: (Point, Point) -> Color -> Color -> Animation
  blockHit poss c1 c2 = Animation $ map (mzipPairs poss)
    [ (blank           , cSym BrCyan '&')
    , (blank           , cSym BrCyan '&')
    , (blank           , blank)
    , (cSym BrBlue  '{', blank)
    , (cSym BrBlue  '{', cSym BrCyan '&')
    , (cSym BrBlue  '{', blank)
    , (cSym BrBlue  '}', blank)
    , (cSym BrBlue  '}', blank)
    , (cSym BrBlue  '}', blank)
    , (cSym c1      '\\',blank)
    , (cSym c1      '|', blank)
    , (cSym c1      '/', blank)
    , (cSym c1      '-', blank)
    , (cSym c2      '\\',blank)
    , (cSym c2      '|', blank)
    , (cSym c2      '/', blank)
    ]
  
  -- | Attack that is blocked.
  blockMiss :: (Point, Point) -> Animation
  blockMiss poss = Animation $ map (mzipPairs poss)
    [ (blank           , cSym BrCyan '&')
    , (blank           , cSym BrCyan '&')
    , (blank           , blank)
    , (cSym BrBlue  '{', blank)
    , (cSym BrBlue  '{', cSym BrCyan '&')
    , (cSym BrBlue  '{', blank)
    , (cSym BrBlue  '{', blank)
    , (cSym BrBlue  '}', blank)
    , (cSym Blue    '}', blank)
    , (cSym Blue    '}', blank)
    , (cSym Blue    '}', blank)
    ]
  
  -- | Attack that is subtle (e.g., damage dice 0).
  subtleHit :: (Point, Point) -> Animation
  subtleHit poss = Animation $ map (mzipPairs poss)
    [ (blank           , cSym BrCyan '&')
    , (blank           , blank)
    , (blank           , cSym BrYellow '&')
    , (cSym BrBlue  '\\',blank)
    , (blank           , cSym BrYellow '&')
    , (cSym BrBlue  '/', blank)
    , (blank           , blank)
    ]
  
  -- | Death animation for an organic body.
  deathBody :: Point -> Animation
  deathBody pos = Animation $ map (mzipSingleton pos)
    [ cSym Red '%'
    , cSym Red '-'
    , cSym Red '-'
    , cSym Red '\\'
    , cSym Red '\\'
    , cSym Red '|'
    , cSym Red '|'
    , cSym Red '%'
    , cSym Red '%'
    , cSym Red '%'
    , cSym Red '%'
    , cSym Red ';'
    , cSym Red ';'
    ]
  
  -- | Death animation for an organic body, short version (e.g., for enemies).
  shortDeathBody :: Point -> Animation
  shortDeathBody pos = Animation $ map (mzipSingleton pos)
    [ cSym Red '%'
    , cSym Red '-'
    , cSym Red '\\'
    , cSym Red '|'
    , cSym Red '%'
    , cSym Red '%'
    , cSym Red '%'
    , cSym Red ';'
    , cSym Red ','
    ]
  
  -- | Mark actor location animation.
  actorX :: Point -> Animation
  actorX pos = Animation $ map (mzipSingleton pos)
    [ cSym BrMagenta 'X'
    , cSym BrMagenta 'X'
    , blank
    , blank
    ]
  
  -- | Actor teleport animation.
  teleport :: (Point, Point) -> Animation
  teleport poss = Animation $ map (mzipPairs poss)
    [ (cSym BrMagenta 'o', cSym Magenta   '.')
    , (cSym BrMagenta 'O', cSym Magenta   '.')
    , (cSym Magenta   'o', cSym Magenta   'o')
    , (cSym Magenta   '.', cSym BrMagenta 'O')
    , (cSym Magenta   '.', cSym BrMagenta 'o')
    , (cSym Magenta   '.', blank)
    , (blank             , blank)
    ]
  
  -- | Terrain feature vanishing animation.
  vanish :: Point -> Animation
  vanish pos = Animation $ map (mzipSingleton pos)
    [ cSym BrMagenta 'o'
    , cSym BrMagenta 'O'
    , cSym Magenta   'o'
    , cSym Magenta   '.'
    , cSym Magenta   '.'
    , blank
    ]
  
  -- | Swap-places animation, both hostile and friendly.
  swapPlaces :: (Point, Point) -> Animation
  swapPlaces poss = Animation $ map (mzipPairs poss)
    [ (cSym BrMagenta 'o', cSym Magenta   'o')
    , (cSym BrMagenta 'd', cSym Magenta   'p')
    , (cSym BrMagenta '.', cSym Magenta   'p')
    , (cSym Magenta   'p', cSym Magenta   '.')
    , (cSym Magenta   'p', cSym BrMagenta 'd')
    , (cSym Magenta   'p', cSym BrMagenta 'd')
    , (cSym Magenta   'o', blank)
    , (blank             , blank)
    ]
  
  fadeout :: ScreenContent -> Bool -> Int -> Rnd Animation
  fadeout ScreenContent{rwidth, rheight} out step = do
    let xbound = rwidth - 1
        ybound = rheight - 1
        margin = (rwidth - 2 * rheight) `div` 2 - 2
        edge = EM.fromDistinctAscList $ zip [1..] ".%&%;:,."
        fadeChar :: Int -> Int -> Int -> Int -> Char
        fadeChar !r !n !x !y =
          let d = x - 2 * y
              ndy = n - d - 2 * ybound
              ndx = n + d - xbound - 1  -- @-1@ for asymmetry
              mnx = if ndy > 0 && ndx > 0
                    then min ndy ndx
                    else max ndy ndx
              v3 = (r `xor` (x * y)) `mod` 3
              k | mnx < 3 || mnx > 10 = mnx
                | (min x (xbound - x - y) + n + v3) `mod` 15 < 11
                  && mnx > 6 = mnx - v3
                | (x + 3 * y + v3) `mod` 30 < 19 = mnx + 1
                | otherwise = mnx
          in EM.findWithDefault ' ' k edge
        rollFrame !n = do
          w <- randomWord32
          -- @fromIntegralWrap@ is potentially costly, but arch-independent.
          -- Also, it's fine if it wraps.
          let fadeAttr !y !x = attrChar1ToW32 $
                fadeChar ((fromIntegralWrap :: Word32 -> Int) w) n x y
              fadeLine !y =
                let x1 :: Int
                    {-# INLINE x1 #-}
                    x1 = min xbound (n - 2 * (ybound - y))
                    x2 :: Int
                    {-# INLINE x2 #-}
                    x2 = max 0 (xbound - (n - 2 * y))
                in [ (PointUI 0 y, map (fadeAttr y) [0..x1])
                   , (PointUI (2 * x2) y, map (fadeAttr y) [x2..xbound]) ]
          return $! concatMap fadeLine [0..ybound]
        fs | out = [3, 3 + step .. rwidth - margin]
           | otherwise = [rwidth - margin, rwidth - margin - step .. 1]
                         ++ [0]  -- no remnants of fadein onscreen, in case of lag
    Animation <$> mapM rollFrame fs
  