{-# LANGUAGE FlexibleInstances #-}

    ( money
    , rule

    ( rule

import Budget (Budget)

import Budget (Budget, Category (..), Rule)

instance Pretty Category where
    pretty cat = fill 8 $ viaShow cat <> ":"
instance (KnownNat x, KnownNat y, KnownNat z) => Pretty (Budget c '(x, y, z)) where
    pretty budget = "Budget" <+> rule budget
instance (KnownSymbol c) => Pretty (PosMoney c) where
    pretty x = pretty currency <+> pretty value
      where
        currency = symbolVal x
        value = unP. unPosMoney $ x
instance (KnownNat x, KnownNat y, KnownNat z) => Pretty (Rule '(x, y, z)) where
    pretty x = concatWith (surround "/") . map pretty $ [natVal (Proxy @x), natVal (Proxy @y), natVal (Proxy @z)]

    header = "Budget with rule" <+> rule budget
    need = fill width "Needs:" <+> money (Budget.needs budget)
    want = fill width "Wants:" <+> money (Budget.wants budget)
    saving = fill width "Savings:" <+> money (Budget.savings budget)
    width = 8

    header = pretty budget
    need = pretty Needs <+> pretty (Budget.needs budget)
    want = pretty Wants <+> pretty (Budget.wants budget)
    saving = pretty Savings <+> pretty (Budget.savings budget)

rule :: forall a b c proxy (curr :: Symbol). (KnownNat a, KnownNat b, KnownNat c) => proxy curr '(a, b, c) -> Doc ()

rule :: forall a b c proxy (curr :: Symbol) ann. (KnownNat a, KnownNat b, KnownNat c) => proxy curr '(a, b, c) -> Doc ann

money :: forall c. (KnownSymbol c) => PosMoney c -> Doc ()
money x = pretty currency <+> pretty value
  where
    value = unP . unPosMoney $ x
    currency = symbolVal (Proxy @c)

    Category (..),

data Category = Needs | Wants | Savings deriving (Show)