{-# LANGUAGE DataKinds #-}
module Diff.Spec where

import Category
import Data.Bifunctor.Join
import Data.Functor.Listable
import Data.String
import Diff
import Diffing (getLabel)
import Interpreter
import Patch
import Prologue
import Term
import Test.Hspec
import Test.Hspec.LeanCheck

spec :: Spec
spec = parallel $ do
  prop "equality is reflexive" $
    \ a -> let diff = unListableDiff a :: SyntaxDiff String '[Category] in
      diff `shouldBe` diff

  prop "equal terms produce identity diffs" $
    \ a -> let term = unListableF a :: SyntaxTerm String '[Category] in
      diffCost (diffTerms wrap (==) diffCost getLabel term term) `shouldBe` 0

  describe "beforeTerm" $ do
    prop "recovers the before term" $
      \ a b -> let diff = diffTerms wrap (==) diffCost getLabel (unListableF a) (unListableF b :: SyntaxTerm String '[Category]) in
        beforeTerm diff `shouldBe` Just (unListableF a)

  describe "afterTerm" $ do
    prop "recovers the after term" $
      \ a b -> let diff = diffTerms wrap (==) diffCost getLabel (unListableF a) (unListableF b :: SyntaxTerm String '[Category]) in
        afterTerm diff `shouldBe` Just (unListableF b)

unListableDiff :: Functor f => ListableF (Free (TermF f (ListableF (Join (,)) annotation))) (Patch (ListableF (Term f) annotation)) -> Diff f annotation
unListableDiff diff = transFreeT (first unListableF) $ fmap unListableF <$> unListableF diff