{-# LANGUAGE DataKinds #-}
module DiffSpec where

import Category
import Data.Functor.Both
import Data.Functor.Listable ()
import Data.Record
import RWS
import Diff
import Info
import Interpreter
import Syntax
import Term
import Test.Hspec
import Test.Hspec.LeanCheck

spec :: Spec
spec = parallel $ do
  let decorate = defaultFeatureVectorDecorator (category . termAnnotation)
  prop "equality is reflexive" $
    \ diff -> diff `shouldBe` (diff :: Diff Syntax (Record '[Category]) (Record '[Category]))

  prop "equal terms produce identity diffs" $
    \ a -> let term = decorate (a :: Term Syntax (Record '[Category])) in
      diffCost (diffTerms term term) `shouldBe` 0

  describe "beforeTerm" $ do
    prop "recovers the before term" $
      \ a b -> let diff = diffTerms a b :: Diff Syntax (Record '[Category]) (Record '[Category]) in
        beforeTerm diff `shouldBe` Just a

  describe "afterTerm" $ do
    prop "recovers the after term" $
      \ a b -> let diff = diffTerms a b :: Diff Syntax (Record '[Category]) (Record '[Category]) in
        afterTerm diff `shouldBe` Just b