module SplitSpec where

import Test.Hspec
import Split
import qualified Data.Set as Set
import Diff
import Range
import Test.Hspec.QuickCheck
import Test.QuickCheck hiding (Fixed)
import Control.Comonad.Cofree
import Control.Monad.Free hiding (unfold)
import qualified Data.Maybe as Maybe
import Line
import Row
import Patch
import Syntax
import ArbitraryTerm

instance Arbitrary a => Arbitrary (Row a) where
  arbitrary = oneof [
    Row <$> arbitrary <*> arbitrary ]

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

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

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

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

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

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

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

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

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

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

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

  describe "openLineBy" $ do
    it "produces the earliest non-empty line in a list, if open" $
      openLineBy (openTerm $ makeSource "\n ") [
        Line [ Info (Range 1 2) mempty :< Leaf "" ],
        Line [ Info (Range 0 1) mempty :< Leaf "" ]
      ] `shouldBe` (Just $ Line [ Info (Range 1 2) mempty :< Leaf "" ])

    it "returns Nothing if the earliest non-empty line is closed" $
      openLineBy (openTerm $ makeSource "\n") [
        Line [ Info (Range 0 1) mempty :< Leaf "" ]
      ] `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 (makeSource "  ") term `shouldBe` Just term

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

    where
      isOpenBy f (Row a b) = Maybe.isJust (openLineBy f [ a ]) && Maybe.isJust (openLineBy f [ b ])
      isClosedBy f (Row a@(Line _) b@(Line _)) = Maybe.isNothing (openLineBy f [ a ]) && Maybe.isNothing (openLineBy f [ b ])
      isClosedBy _ (Row _ _) = False

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

      getTotalRange (Source (i, list)) = Range 0 $ i + length list

      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 $ substring rangeA sourceA ++ substring rangeB sourceB)

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