{-# LANGUAGE DataKinds #-}
module InterpreterSpec where

import Category
import Data.Array
import Data.Functor.Foldable hiding (Nil)
import Data.Functor.Listable
import Data.RandomWalkSimilarity
import Data.Record
import Data.String
import Diff
import Info
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
    let decorate = defaultFeatureVectorDecorator (category . headF)
    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
          stripDiff (diffTerms (decorate termA) (decorate termB)) `shouldBe` replacing termA termB

    prop "produces correct diffs" $
      \ a b -> let diff = stripDiff $ diffTerms (decorate (unListableF a)) (decorate (unListableF b :: 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 = decorate (unListableF a :: SyntaxTerm String '[Category])
                 diff = diffTerms term term in
                 diffCost diff `shouldBe` 0

    it "produces unbiased insertions within branches" $
      let term s = decorate (cofree ((StringLiteral :. Nil) :< Indexed [ cofree ((StringLiteral :. Nil) :< Leaf s) ]))
          root = cofree . ((Just (listArray (0, defaultD) (repeat 0)) :. Program :. Nil) :<) . Indexed in
      stripDiff (diffTerms (root [ term "b" ]) (root [ term "a", term "b" ])) `shouldBe` wrap (pure (Program :. Nil) :< Indexed [ inserting (stripTerm (term "a")), cata wrap (fmap pure (stripTerm (term "b"))) ])