-- |
-- Module      : Verismith.Circuit.Internal
-- Description : Internal helpers for generation.
-- Copyright   : (c) 2018-2019, Yann Herklotz
-- License     : GPL-3
-- Maintainer  : yann [at] yannherklotz [dot] com
-- Stability   : experimental
-- Portability : POSIX
--
-- Internal helpers for generation.
module Verismith.Circuit.Internal
  ( fromNode,
    filterGr,
    only,
    inputs,
    outputs,
  )
where

import Data.Graph.Inductive (Graph, Node)
import qualified Data.Graph.Inductive as G
import qualified Data.Text as T

-- | Convert an integer into a label.
--
-- >>> fromNode 5
-- "w5"
fromNode :: Int -> T.Text
fromNode :: Int -> Text
fromNode Int
node = String -> Text
T.pack (String -> Text) -> String -> Text
forall a b. (a -> b) -> a -> b
$ String
"w" String -> String -> String
forall a. Semigroup a => a -> a -> a
<> Int -> String
forall a. Show a => a -> String
show Int
node

-- | General function which runs 'filter' over a graph.
filterGr :: (Graph gr) => gr n e -> (Node -> Bool) -> [Node]
filterGr :: forall (gr :: * -> * -> *) n e.
Graph gr =>
gr n e -> (Int -> Bool) -> [Int]
filterGr gr n e
graph Int -> Bool
f = (Int -> Bool) -> [Int] -> [Int]
forall a. (a -> Bool) -> [a] -> [a]
filter Int -> Bool
f ([Int] -> [Int]) -> [Int] -> [Int]
forall a b. (a -> b) -> a -> b
$ gr n e -> [Int]
forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> [Int]
G.nodes gr n e
graph

-- | Takes two functions that return an 'Int', and compares there results to 0
-- and not 0 respectively. This result is returned.
only ::
  (Graph gr) =>
  gr n e ->
  (gr n e -> Node -> Int) ->
  (gr n e -> Node -> Int) ->
  Node ->
  Bool
only :: forall (gr :: * -> * -> *) n e.
Graph gr =>
gr n e
-> (gr n e -> Int -> Int) -> (gr n e -> Int -> Int) -> Int -> Bool
only gr n e
graph gr n e -> Int -> Int
fun1 gr n e -> Int -> Int
fun2 Int
n = gr n e -> Int -> Int
fun1 gr n e
graph Int
n Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
0 Bool -> Bool -> Bool
&& gr n e -> Int -> Int
fun2 gr n e
graph Int
n Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
/= Int
0

-- | Returns all the input nodes to a graph, which means nodes that do not have
-- an input themselves.
inputs :: (Graph gr) => gr n e -> [Node]
inputs :: forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> [Int]
inputs gr n e
graph = gr n e -> (Int -> Bool) -> [Int]
forall (gr :: * -> * -> *) n e.
Graph gr =>
gr n e -> (Int -> Bool) -> [Int]
filterGr gr n e
graph ((Int -> Bool) -> [Int]) -> (Int -> Bool) -> [Int]
forall a b. (a -> b) -> a -> b
$ gr n e
-> (gr n e -> Int -> Int) -> (gr n e -> Int -> Int) -> Int -> Bool
forall (gr :: * -> * -> *) n e.
Graph gr =>
gr n e
-> (gr n e -> Int -> Int) -> (gr n e -> Int -> Int) -> Int -> Bool
only gr n e
graph gr n e -> Int -> Int
forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> Int -> Int
G.indeg gr n e -> Int -> Int
forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> Int -> Int
G.outdeg

-- | Returns all the output nodes to a graph, similar to the 'inputs' function.
outputs :: (Graph gr) => gr n e -> [Node]
outputs :: forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> [Int]
outputs gr n e
graph = gr n e -> (Int -> Bool) -> [Int]
forall (gr :: * -> * -> *) n e.
Graph gr =>
gr n e -> (Int -> Bool) -> [Int]
filterGr gr n e
graph ((Int -> Bool) -> [Int]) -> (Int -> Bool) -> [Int]
forall a b. (a -> b) -> a -> b
$ gr n e
-> (gr n e -> Int -> Int) -> (gr n e -> Int -> Int) -> Int -> Bool
forall (gr :: * -> * -> *) n e.
Graph gr =>
gr n e
-> (gr n e -> Int -> Int) -> (gr n e -> Int -> Int) -> Int -> Bool
only gr n e
graph gr n e -> Int -> Int
forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> Int -> Int
G.outdeg gr n e -> Int -> Int
forall (gr :: * -> * -> *) a b. Graph gr => gr a b -> Int -> Int
G.indeg