{-# LANGUAGE DataKinds #-}
module Data.RandomWalkSimilarity.Spec where

import Category
import Data.Bifunctor
import Data.Functor.Listable
import RWS
import Data.Record
import Data.String
import Data.These
import Diff
import Info
import Patch
import Prologue
import Syntax
import Term
import Test.Hspec
import Test.Hspec.LeanCheck

spec :: Spec
spec = parallel $ do
  let positively = succ . abs
  describe "pqGramDecorator" $ do
    prop "produces grams with stems of the specified length" $
      \ (term, p, q) -> pqGramDecorator (rhead . headF) (positively p) (positively q) (unListableF term :: SyntaxTerm String '[Category]) `shouldSatisfy` all ((== positively p) . length . stem . rhead)

    prop "produces grams with bases of the specified width" $
      \ (term, p, q) -> pqGramDecorator (rhead . headF) (positively p) (positively q) (unListableF term :: SyntaxTerm String '[Category]) `shouldSatisfy` all ((== positively q) . length . base . rhead)

  describe "featureVectorDecorator" $ do
    prop "produces a vector of the specified dimension" $
      \ (term, p, q, d) -> featureVectorDecorator (rhead . headF) (positively p) (positively q) (positively d) (unListableF term :: SyntaxTerm String '[Category]) `shouldSatisfy` all ((== positively d) . maybe 0 length . rhead)

  describe "rws" $ do
    prop "produces correct diffs" $
      \ (as, bs) -> let tas = decorate <$> (unListableF <$> as :: [SyntaxTerm String '[Category]])
                        tbs = decorate <$> (unListableF <$> bs :: [SyntaxTerm String '[Category]])
                        root = cofree . ((Program :. Nil) :<) . Indexed
                        diff = wrap (pure (Program :. Nil) :< Indexed (stripDiff . diffThese <$> rws editDistance canCompare tas tbs)) in
        (beforeTerm diff, afterTerm diff) `shouldBe` (Just (root (stripTerm <$> tas)), Just (root (stripTerm <$> tbs)))

    it "produces unbiased insertions within branches" $
      let (a, b) = (decorate (cofree ((StringLiteral :. Nil) :< Indexed [ cofree ((StringLiteral :. Nil) :< Leaf ("a" :: String)) ])), decorate (cofree ((StringLiteral :. Nil) :< Indexed [ cofree ((StringLiteral :. Nil) :< Leaf "b") ]))) in
      fmap (bimap stripTerm stripTerm) (rws editDistance canCompare [ b ] [ a, b ]) `shouldBe` fmap (bimap stripTerm stripTerm) [ That a, These b b ]

  where canCompare = (==) `on` extract

        decorate :: SyntaxTerm leaf '[Category] -> SyntaxTerm leaf '[Maybe FeatureVector, Category]
        decorate = defaultFeatureVectorDecorator (category . headF)

        diffThese = these deleting inserting replacing

        editDistance = these (const 1) (const 1) (const (const 0))