{-# LANGUAGE DataKinds #-}
module InterpreterSpec where

import Category
import Data.Functor.Both
import Data.Functor.Foldable hiding (Nil)
import Data.Functor.Listable
import Data.Record
import Data.String
import Diff
import Interpreter
import Patch
import Prologue
import Syntax
import Term
import Test.Hspec (Spec, describe, it, parallel)
import Test.Hspec.Expectations.Pretty
import Test.Hspec.LeanCheck

spec :: Spec
spec = parallel $ do
  describe "interpret" $ do
    it "returns a replacement when comparing two unicode equivalent terms" $
      let termA = cofree $ (StringLiteral :. Nil) :< Leaf ("t\776" :: String)
          termB = cofree $ (StringLiteral :. Nil) :< Leaf "\7831" in
          diffTerms (both termA termB) `shouldBe` replacing termA termB

    prop "produces correct diffs" $
      \ a b -> let diff = diffTerms (unListableF <$> both a b :: Both (SyntaxTerm String '[Category])) in
                   (beforeTerm diff, afterTerm diff) `shouldBe` (Just (unListableF a), Just (unListableF b))

    prop "constructs zero-cost diffs of equal terms" $
      \ a -> let term = (unListableF a :: SyntaxTerm String '[Category])
                 diff = diffTerms (pure term) in
                 diffCost diff `shouldBe` 0

    it "produces unbiased insertions within branches" $
      let term s = cofree ((StringLiteral :. Nil) :< Indexed [ cofree ((StringLiteral :. Nil) :< Leaf s) ]) :: SyntaxTerm String '[Category]
          root = cofree . ((Program :. Nil) :<) . Indexed in
      diffTerms (both (root [ term "b" ]) (root [ term "a", term "b" ])) `shouldBe` wrap (pure (Program :. Nil) :< Indexed [ inserting (term "a"), cata wrap (fmap pure (term "b")) ])