module AlignmentSpec where

import Test.Hspec
import Test.Hspec.QuickCheck
import Test.QuickCheck hiding (Fixed)
import Data.Text.Arbitrary ()

import Alignment
import Control.Comonad.Cofree
import Control.Monad.Free hiding (unfold)
import Data.Functor.Both
import Diff
import qualified Data.Maybe as Maybe
import Data.Functor.Identity
import Source hiding ((++))
import Line
import Row
import Range
import Syntax
import ArbitraryTerm ()

instance Arbitrary a => Arbitrary (Both a) where
  arbitrary = pure (curry Both) <*> arbitrary <*> arbitrary

instance Arbitrary a => Arbitrary (Row a) where
  arbitrary = Row <$> arbitrary

instance Arbitrary a => Arbitrary (Line a) where
  arbitrary = oneof [
    makeLine <$> arbitrary,
    const EmptyLine <$> (arbitrary :: Gen ()) ]

instance Arbitrary a => Arbitrary (Source a) where
  arbitrary = fromList <$> arbitrary

arbitraryLeaf :: Gen (Source Char, Info, Syntax (Source Char) f)
arbitraryLeaf = toTuple <$> arbitrary
  where toTuple string = (string, Info (Range 0 $ length string) mempty, Leaf string)

spec :: Spec
spec = parallel $ do
  describe "splitAnnotatedByLines" $ do
    prop "outputs one row for single-line unchanged leaves" $
      forAll (arbitraryLeaf `suchThat` isOnSingleLine) $
        \ (source, info@(Info range categories), syntax) -> splitAnnotatedByLines (pure source) (pure range) (pure categories) syntax `shouldBe` [
          makeRow (makeLine [ Free $ Annotated info $ Leaf source ]) (makeLine [ Free $ Annotated info $ Leaf source ]) ]

    prop "outputs one row for single-line empty unchanged indexed nodes" $
      forAll (arbitrary `suchThat` (\ a -> filter (/= '\n') (toList a) == toList a)) $
          \ source -> splitAnnotatedByLines (pure source) (pure (getTotalRange source)) (pure mempty) (Indexed [] :: Syntax String (Diff String Info)) `shouldBe` [
            makeRow (makeLine [ Free $ Annotated (Info (getTotalRange source) mempty) $ Indexed [] ]) (makeLine [ Free $ Annotated (Info (getTotalRange source) mempty) $ Indexed [] ]) ]

    prop "preserves line counts in equal sources" $
      \ source ->
        length (splitAnnotatedByLines (pure source) (pure (getTotalRange source)) (pure mempty) (Indexed . fst $ foldl combineIntoLeaves ([], 0) source)) `shouldBe` length (filter (== '\n') $ toList source) + 1

    prop "produces the maximum line count in inequal sources" $
      \ sources ->
        let (sourceA, sourceB) = runBoth sources in
          length (splitAnnotatedByLines sources (getTotalRange <$> sources) (pure mempty) (Indexed $ Prelude.zipWith (leafWithRangesInSources sourceA sourceB) (actualLineRanges (getTotalRange sourceA) sourceA) (actualLineRanges (getTotalRange sourceB) sourceB))) `shouldBe` max (length (filter (== '\n') $ toList sourceA) + 1) (length (filter (== '\n') $ toList sourceB) + 1)

  describe "adjoinRowsBy" $ do
    prop "is identity on top of no rows" $
      \ a -> adjoinRowsBy (pure openMaybe) [] a == [ a ]

    prop "appends onto open rows" $
      forAll ((arbitrary `suchThat` isOpenBy openMaybe) >>= \ a -> (,) a <$> (arbitrary `suchThat` isOpenBy openMaybe)) $
        \ (a@(Row (Both (a1, b1))), b@(Row (Both (a2, b2)))) ->
          adjoinRowsBy (pure openMaybe) [ a ] b `shouldBe` [ Row $ makeLine <$> ((++) <$> (unLine <$> unRow a) <*> (unLine <$> unRow b)) ]

    prop "does not append onto closed rows" $
      forAll ((arbitrary `suchThat` isClosedBy openMaybe) >>= \ a -> (,) a <$> (arbitrary `suchThat` isClosedBy openMaybe)) $
        \ (a, b) -> adjoinRowsBy (pure openMaybe) [ a ] b `shouldBe` [ b, a ]

    prop "does not promote elements through empty lines onto closed lines" $
      forAll ((arbitrary `suchThat` isClosedBy openMaybe) >>= \ a -> (,) a <$> (arbitrary `suchThat` isClosedBy openMaybe)) $
        \ (a, b) -> adjoinRowsBy (pure openMaybe) [ makeRow EmptyLine EmptyLine, a ] b `shouldBe` [ b, makeRow EmptyLine EmptyLine, a ]

    prop "promotes elements through empty lines onto open lines" $
      forAll ((arbitrary `suchThat` isOpenBy openMaybe) >>= \ a -> (,) a <$> (arbitrary `suchThat` isOpenBy openMaybe)) $
        \ (a, b) -> adjoinRowsBy (pure openMaybe) [ makeRow EmptyLine EmptyLine, a ] b `shouldBe` makeRow EmptyLine EmptyLine : adjoinRowsBy (pure openMaybe) [ a ] b

  describe "splitTermByLines" $ do
    prop "preserves line count" $
      \ source -> let range = getTotalRange source in
        splitTermByLines (Info range mempty :< Leaf source) source `shouldBe` (pure . (:< Leaf source) . (`Info` mempty) <$> actualLineRanges range source, range)

  describe "openLineBy" $ do
    it "produces the earliest non-empty line in a list, if open" $
      openLineBy openMaybe [
        pure (Just True),
        pure (Just False)
      ] `shouldBe` (Just $ pure $ Just True)

    it "returns Nothing if the earliest non-empty line is closed" $
      openLineBy openMaybe [
        pure Nothing, pure (Just True)
      ] `shouldBe` Nothing

  describe "openTerm" $ do
    it "returns Just the term if its substring does not end with a newline" $
      let term = Info (Range 0 2) mempty :< Leaf "" in openTerm (fromList "  ") (Identity term) `shouldBe` Just (Identity term)

    it "returns Nothing for terms whose substring ends with a newline" $
      openTerm (fromList " \n") (Identity $ Info (Range 0 2) mempty :< Leaf "") `shouldBe` Nothing

    where
      isOpenBy f (Row lines) = and (Maybe.isJust . openLineBy f . pure <$> lines)
      isClosedBy f (Row lines@(Both (Line _, Line _))) = and (Maybe.isNothing . openLineBy f . pure <$> lines)
      isClosedBy _ _ = False

      isOnSingleLine (a, _, _) = filter (/= '\n') (toList a) == toList a

      getTotalRange (Source vector) = Range 0 $ length vector

      combineIntoLeaves (leaves, start) char = (leaves ++ [ Free $ Annotated (Info (Range start $ start + 1) mempty, Info (Range start $ start + 1) mempty) (Leaf [ char ]) ], start + 1)

      leafWithRangesInSources sourceA sourceB rangeA rangeB = Free $ Annotated (Info rangeA mempty, Info rangeB mempty) (Leaf $ toList sourceA ++ toList sourceB)

      openMaybe :: Maybe Bool -> Maybe (Maybe Bool)
      openMaybe (Just a) = Just (Just a)
      openMaybe Nothing = Nothing