{-|
Module      : Verismith.Circuit.Base
Description : Base types for the circuit module.
Copyright   : (c) 2019, Yann Herklotz Grave
License     : GPL-3
Maintainer  : yann [at] yannherklotz [dot] com
Stability   : experimental
Portability : POSIX

Base types for the circuit module.
-}

module Verismith.Circuit.Base
    ( Gate(..)
    , Circuit(..)
    , CNode(..)
    , CEdge(..)
    )
where

import           Data.Graph.Inductive (Gr, LEdge, LNode)
import           System.Random

-- | The types for all the gates.
data Gate = And
          | Or
          | Xor
          deriving (Show, Eq, Enum, Bounded, Ord)

-- | Newtype for the Circuit which implements a Graph from fgl.
newtype Circuit = Circuit { getCircuit :: Gr Gate () }

-- | Newtype for a node in the circuit, which is an 'LNode Gate'.
newtype CNode = CNode { getCNode :: LNode Gate }

-- | Newtype for a named edge which is empty, as it does not need a label.
newtype CEdge = CEdge { getCEdge :: LEdge () }

instance Random Gate where
  randomR (a, b) g =
    case randomR (fromEnum a, fromEnum b) g of
      (x, g') -> (toEnum x, g')

  random = randomR (minBound, maxBound)