{-# LANGUAGE DataKinds #-}
module InterpreterSpec where

import Category
import Data.Functor.Foldable
import Data.RandomWalkSimilarity
import Data.Record
import Diff
import Info
import Interpreter
import Patch
import Prologue
import Syntax
import Term.Arbitrary
import Test.Hspec
import Test.Hspec.QuickCheck

spec :: Spec
spec = parallel $ do
  describe "interpret" $ do
    let decorate = defaultFeatureVectorDecorator (category . headF)
    let compare = ((==) `on` category . extract)
    it "returns a replacement when comparing two unicode equivalent terms" $
      let termA = cofree $ (StringLiteral .: RNil) :< Leaf ("t\776" :: Text)
          termB = cofree $ (StringLiteral .: RNil) :< Leaf "\7831" in
          stripDiff (diffTerms wrap compare diffCost (decorate termA) (decorate termB)) `shouldBe` replacing termA termB

    prop "produces correct diffs" $
      \ a b -> let diff = stripDiff $ diffTerms wrap compare diffCost (decorate (toTerm a)) (decorate (toTerm (b :: ArbitraryTerm Text (Record '[Category])))) in
                   (beforeTerm diff, afterTerm diff) `shouldBe` (Just (toTerm a), Just (toTerm b))

    prop "constructs zero-cost diffs of equal terms" $
      \ a -> let term = decorate (toTerm (a :: ArbitraryTerm Text (Record '[Category])))
                 diff = diffTerms wrap compare diffCost term term in
                 diffCost diff `shouldBe` 0

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