{-# LANGUAGE DeriveTraversable #-}
{-# LANGUAGE DeriveFoldable #-}
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE TemplateHaskell #-}
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-- | Common data types for Xanthous
--------------------------------------------------------------------------------
module Xanthous.Data
  ( Position(..)
  , x
  , y

  , Positioned(..)
  , position
  , positioned
  , loc

    -- *
  , Direction(..)
  , opposite
  , move
  , asPosition
  ) where
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import Xanthous.Prelude hiding (Left, Down, Right)
import Test.QuickCheck (Arbitrary, CoArbitrary, Function)
import Test.QuickCheck.Arbitrary.Generic
import Data.Group
import Brick (Location(Location))
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import Xanthous.Util (EqEqProp(..), EqProp)
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data Position where
  Position :: { _x :: Int
             , _y :: Int
             } -> Position
  deriving stock (Show, Eq, Generic, Ord)
  deriving anyclass (Hashable, CoArbitrary, Function)
  deriving EqProp via EqEqProp Position
makeLenses ''Position

instance Arbitrary Position where
  arbitrary = genericArbitrary
  shrink = genericShrink

instance Semigroup Position where
  (Position x₁ y₁) <> (Position x₂ y₂) = Position (x₁ + x₂) (y₁ + y₂)

instance Monoid Position where
  mempty = Position 0 0

instance Group Position where
  invert (Position px py) = Position (-px) (-py)

data Positioned a where
  Positioned :: Position -> a -> Positioned a
  deriving stock (Show, Eq, Ord, Functor, Foldable, Traversable, Generic)
  deriving anyclass (CoArbitrary, Function)

instance Arbitrary a => Arbitrary (Positioned a) where
  arbitrary = Positioned <$> arbitrary <*> arbitrary

position :: Lens' (Positioned a) Position
position = lens
  (\(Positioned pos _) -> pos)
  (\(Positioned _ a) pos -> Positioned pos a)

positioned :: Lens (Positioned a) (Positioned b) a b
positioned = lens
  (\(Positioned _ x') -> x')
  (\(Positioned pos _) x' -> Positioned pos x')

loc :: Iso' Position Location
loc = iso hither yon
  where
    hither (Position px py) = Location (px, py)
    yon (Location (lx, ly)) = Position lx ly

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data Direction where
  Up        :: Direction
  Down      :: Direction
  Left      :: Direction
  Right     :: Direction
  UpLeft    :: Direction
  UpRight   :: Direction
  DownLeft  :: Direction
  DownRight :: Direction
  deriving stock (Show, Eq, Generic)

instance Arbitrary Direction where
  arbitrary = genericArbitrary
  shrink = genericShrink

opposite :: Direction -> Direction
opposite Up        = Down
opposite Down      = Up
opposite Left      = Right
opposite Right     = Left
opposite UpLeft    = DownRight
opposite UpRight   = DownLeft
opposite DownLeft  = UpRight
opposite DownRight = UpLeft

move :: Direction -> Position -> Position
move Up        = y -~ 1
move Down      = y +~ 1
move Left      = x -~ 1
move Right     = x +~ 1
move UpLeft    = move Up . move Left
move UpRight   = move Up . move Right
move DownLeft  = move Down . move Left
move DownRight = move Down . move Right

asPosition :: Direction -> Position
asPosition dir = move dir mempty