1 files changed, 64 insertions, 0 deletions
diff --git a/src/Xanthous/Entities.hs b/src/Xanthous/Entities.hs
new file mode 100644
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+++ b/src/Xanthous/Entities.hs
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+{-# LANGUAGE UndecidableInstances #-}
+
+module Xanthous.Entities
+  ( Draw(..)
+  , DrawCharacter(..)
+  , DrawStyledCharacter(..)
+  , Entity
+
+  , Color(..)
+  , KnownColor(..)
+  ) where
+
+import Xanthous.Prelude
+import Brick
+import Data.Typeable
+import qualified Graphics.Vty.Attributes as Vty
+import qualified Graphics.Vty.Image as Vty
+
+class Draw a where
+  draw :: a -> Widget n
+
+newtype DrawCharacter (char :: Symbol) (a :: Type) where
+  DrawCharacter :: a -> DrawCharacter char a
+
+instance KnownSymbol char => Draw (DrawCharacter char a) where
+  draw _ = str $ symbolVal @char Proxy
+
+--------------------------------------------------------------------------------
+
+data Color = Black | Red | Green | Yellow | Blue | Magenta | Cyan | White
+
+class KnownColor (color :: Color) where
+  colorVal :: forall proxy. proxy color -> Vty.Color
+
+instance KnownColor 'Black where colorVal _ = Vty.black
+instance KnownColor 'Red where colorVal _ = Vty.red
+instance KnownColor 'Green where colorVal _ = Vty.green
+instance KnownColor 'Yellow where colorVal _ = Vty.yellow
+instance KnownColor 'Blue where colorVal _ = Vty.blue
+instance KnownColor 'Magenta where colorVal _ = Vty.magenta
+instance KnownColor 'Cyan where colorVal _ = Vty.cyan
+instance KnownColor 'White where colorVal _ = Vty.white
+
+newtype DrawStyledCharacter (fg :: Color) (bg :: Color) (char :: Symbol) (a :: Type) where
+  DrawStyledCharacter :: a -> DrawStyledCharacter fg bg char a
+
+instance
+  ( KnownColor fg
+  , KnownColor bg
+  , KnownSymbol char
+  )
+  => Draw (DrawStyledCharacter fg bg char a) where
+  draw _ = raw $ Vty.string attr $ symbolVal @char Proxy
+    where attr = Vty.Attr
+            { Vty.attrStyle = Vty.Default
+            , Vty.attrForeColor = Vty.SetTo $ colorVal @fg Proxy
+            , Vty.attrBackColor = Vty.SetTo $ colorVal @bg Proxy
+            , Vty.attrURL = Vty.Default
+            }
+
+--------------------------------------------------------------------------------
+
+class (Show a, Eq a, Draw a) => Entity a
+instance (Show a, Eq a, Draw a) => Entity a