{-# LANGUAGE FlexibleInstances #-}
module AlignmentSpec where

import Alignment
import ArbitraryTerm ()
import Control.Arrow ((&&&))
import Control.Monad.State
import Data.Align hiding (align)
import Data.Bifunctor
import Data.Bifunctor.Join
import Data.Functor.Both as Both
import Data.Functor.Identity
import Data.List (nub)
import Data.Monoid
import Data.String
import Data.Text.Arbitrary ()
import Data.These
import Info
import Patch
import Prologue hiding (fst, snd)
import qualified Prologue
import Range
import qualified Source
import SplitDiff
import Syntax
import Term
import Test.Hspec
import Test.Hspec.QuickCheck
import Test.QuickCheck

spec :: Spec
spec = parallel $ do
  describe "alignBranch" $ do
    it "produces symmetrical context" $
      alignBranch getRange ([] :: [Identity [Join These (SplitDiff String Info)]]) (both [Range 0 2, Range 2 4] [Range 0 2, Range 2 4]) `shouldBe`
        [ Join (These (Range 0 2, [])
                      (Range 0 2, []))
        , Join (These (Range 2 4, [])
                      (Range 2 4, []))
        ]

    it "produces asymmetrical context" $
      alignBranch getRange ([] :: [Identity [Join These (SplitDiff String Info)]]) (both [Range 0 2, Range 2 4] [Range 0 1]) `shouldBe`
        [ Join (These (Range 0 2, [])
                      (Range 0 1, []))
        , Join (This  (Range 2 4, []))
        ]

    prop "covers every input line" $
      \ elements -> let (_, children, ranges) = toAlignBranchInputs elements in
        modifyJoin (fromThese [] []) (unionThese (fmap Prologue.fst <$> alignBranch identity children ranges)) `shouldBe` ranges

    prop "covers every input child" $
      \ elements -> let (_, children, ranges) = toAlignBranchInputs elements in
        sort (nub (keysOfAlignedChildren (alignBranch identity children ranges))) `shouldBe` sort (nub (catMaybes (branchElementKey <$> elements)))

    prop "covers every line of every input child" $
      \ elements -> let (_, children, ranges) = toAlignBranchInputs elements in
        sort (keysOfAlignedChildren (alignBranch identity children ranges)) `shouldBe` sort (do
          (key, lines) <- children
          line <- lines
          these identity identity (++) . runJoin . ([key] <$) $ line)

  describe "alignDiff" $ do
    it "aligns identical branches on a single line" $
      let sources = both (Source.fromList "[ foo ]") (Source.fromList "[ foo ]") in
      align sources (pure (info 0 7) `branch` [ pure (info 2 5) `leaf` "foo" ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 7 `branch` [ info 2 5 `leaf` "foo" ])
                      (info 0 7 `branch` [ info 2 5 `leaf` "foo" ])) ]

    it "aligns identical branches spanning multiple lines" $
      let sources = both (Source.fromList "[\nfoo\n]") (Source.fromList "[\nfoo\n]") in
      align sources (pure (info 0 7) `branch` [ pure (info 2 5) `leaf` "foo" ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 2 `branch` [])
                      (info 0 2 `branch` []))
        , Join (These (info 2 6 `branch` [ info 2 5 `leaf` "foo" ])
                      (info 2 6 `branch` [ info 2 5 `leaf` "foo" ]))
        , Join (These (info 6 7 `branch` [])
                      (info 6 7 `branch` []))
        ]

    it "aligns reformatted branches" $
      let sources = both (Source.fromList "[ foo ]") (Source.fromList "[\nfoo\n]") in
      align sources (pure (info 0 7) `branch` [ pure (info 2 5) `leaf` "foo" ]) `shouldBe` prettyDiff sources
        [ Join (That  (info 0 2 `branch` []))
        , Join (These (info 0 7 `branch` [ info 2 5 `leaf` "foo" ])
                      (info 2 6 `branch` [ info 2 5 `leaf` "foo" ]))
        , Join (That  (info 6 7 `branch` []))
        ]

    it "aligns nodes following reformatted branches" $
      let sources = both (Source.fromList "[ foo ]\nbar\n") (Source.fromList "[\nfoo\n]\nbar\n") in
      align sources (pure (info 0 12) `branch` [ pure (info 0 7) `branch` [ pure (info 2 5) `leaf` "foo" ], pure (info 8 11) `leaf` "bar" ]) `shouldBe` prettyDiff sources
        [ Join (That  (info 0 2 `branch` [ info 0 2 `branch` [] ]))
        , Join (These (info 0 8 `branch` [ info 0 7 `branch` [ info 2 5 `leaf` "foo" ] ])
                      (info 2 6 `branch` [ info 2 6 `branch` [ info 2 5 `leaf` "foo" ] ]))
        , Join (That  (info 6 8 `branch` [ info 6 7 `branch` [] ]))
        , Join (These (info 8 12 `branch` [ info 8 11 `leaf` "bar" ])
                      (info 8 12 `branch` [ info 8 11 `leaf` "bar" ]))
        , Join (These (info 12 12 `branch` [])
                      (info 12 12 `branch` []))
        ]

    it "aligns identical branches with multiple children on the same line" $
      let sources = pure (Source.fromList "[ foo, bar ]") in
      align sources (pure (info 0 12) `branch` [ pure (info 2 5) `leaf` "foo", pure (info 7 10) `leaf` "bar" ]) `shouldBe` prettyDiff sources
        [ Join (runBothWith These (pure (info 0 12 `branch` [ info 2 5 `leaf` "foo", info 7 10 `leaf` "bar" ])) ) ]

    it "aligns insertions" $
      let sources = both (Source.fromList "a") (Source.fromList "a\nb") in
      align sources (both (info 0 1) (info 0 3) `branch` [ pure (info 0 1) `leaf` "a", insert (info 2 3 `leaf` "b") ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 1 `branch` [ info 0 1 `leaf` "a" ])
                      (info 0 2 `branch` [ info 0 1 `leaf` "a" ]))
        , Join (That  (info 2 3 `branch` [ insert (info 2 3 `leaf` "b") ]))
        ]

    it "aligns total insertions" $
      let sources = both (Source.fromList "") (Source.fromList "a") in
      align sources (insert (info 0 1 `leaf` "a")) `shouldBe` prettyDiff sources
        [ Join (That (insert (info 0 1 `leaf` "a"))) ]

    it "aligns insertions into empty branches" $
      let sources = both (Source.fromList "[ ]") (Source.fromList "[a]") in
      align sources (pure (info 0 3) `branch` [ insert (info 1 2 `leaf` "a") ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 3 `branch` [])
                      (info 0 3 `branch` [ insert (info 1 2 `leaf` "a") ])) ]

    it "aligns symmetrically following insertions" $
      let sources = both (Source.fromList "a\nc") (Source.fromList "a\nb\nc") in
      align sources (both (info 0 3) (info 0 5) `branch` [ pure (info 0 1) `leaf` "a", insert (info 2 3 `leaf` "b"), both (info 2 3) (info 4 5) `leaf` "c" ])
        `shouldBe` prettyDiff sources
        [ Join (These (info 0 2 `branch` [ info 0 1 `leaf` "a" ])
                      (info 0 2 `branch` [ info 0 1 `leaf` "a" ]))
        , Join (That  (info 2 4 `branch` [ insert (info 2 3 `leaf` "b") ]))
        , Join (These (info 2 3 `branch` [ info 2 3 `leaf` "c" ])
                      (info 4 5 `branch` [ info 4 5 `leaf` "c" ]))
        ]

    it "symmetrical nodes force the alignment of asymmetrical nodes on both sides" $
      let sources = both (Source.fromList "[ a, b ]") (Source.fromList "[ b, c ]") in
      align sources (pure (info 0 8) `branch` [ delete (info 2 3 `leaf` "a"), both (info 5 6) (info 2 3) `leaf` "b", insert (info 5 6 `leaf` "c") ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 8 `branch` [ delete (info 2 3 `leaf` "a"), info 5 6 `leaf` "b" ])
                      (info 0 8 `branch` [ info 2 3 `leaf` "b", insert (info 5 6 `leaf` "c") ])) ]

    it "when one of two symmetrical nodes must be split, splits the latter" $
      let sources = both (Source.fromList "[ a, b ]") (Source.fromList "[ a\n, b\n]") in
      align sources (both (info 0 8) (info 0 9) `branch` [ pure (info 2 3) `leaf` "a", both (info 5 6) (info 6 7) `leaf` "b" ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 8 `branch` [ info 2 3 `leaf` "a", info 5 6 `leaf` "b" ])
                      (info 0 4 `branch` [ info 2 3 `leaf` "a" ]))
        , Join (That  (info 4 8 `branch` [ info 6 7 `leaf` "b" ]))
        , Join (That  (info 8 9 `branch` []))
        ]

    it "aligns deletions before insertions" $
      let sources = both (Source.fromList "[ a ]") (Source.fromList "[ b ]") in
      align sources (pure (info 0 5) `branch` [ delete (info 2 3 `leaf` "a"), insert (info 2 3 `leaf` "b") ]) `shouldBe` prettyDiff sources
        [ Join (This (info 0 5 `branch` [ delete (info 2 3 `leaf` "a") ]))
        , Join (That (info 0 5 `branch` [ insert (info 2 3 `leaf` "b") ]))
        ]

    it "aligns context-only lines symmetrically" $
      let sources = both (Source.fromList "[\n  a\n,\n  b\n]") (Source.fromList "[\n  a, b\n\n\n]") in
      align sources (both (info 0 13) (info 0 12) `branch` [ pure (info 4 5) `leaf` "a", both (info 10 11) (info 7 8) `leaf` "b" ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 2 `branch` [])
                      (info 0 2 `branch` []))
        , Join (These (info 2 6 `branch` [ info 4 5 `leaf` "a" ])
                      (info 2 9 `branch` [ info 4 5 `leaf` "a", info 7 8 `leaf` "b" ]))
        , Join (These (info 6 8 `branch` [])
                      (info 9 10 `branch` []))
        , Join (These (info 8 12 `branch` [ info 10 11 `leaf` "b" ])
                      (info 10 11 `branch` []))
        , Join (These (info 12 13 `branch` [])
                      (info 11 12 `branch` []))
        ]

    it "aligns asymmetrical nodes preceding their symmetrical siblings conservatively" $
      let sources = both (Source.fromList "[ b, c ]") (Source.fromList "[ a\n, c\n]") in
      align sources (both (info 0 8) (info 0 9) `branch` [ insert (info 2 3 `leaf` "a"), delete (info 2 3 `leaf` "b"), both (info 5 6) (info 6 7) `leaf` "c" ]) `shouldBe` prettyDiff sources
        [ Join (That  (info 0 4 `branch` [ insert (info 2 3 `leaf` "a") ]))
        , Join (These (info 0 8 `branch` [ delete (info 2 3 `leaf` "b"), info 5 6 `leaf` "c" ])
                      (info 4 8 `branch` [ info 6 7 `leaf` "c" ]))
        , Join (That  (info 8 9 `branch` []))
        ]

    it "aligns symmetrical reformatted nodes" $
      let sources = both (Source.fromList "a [ b ]\nc") (Source.fromList "a [\nb\n]\nc") in
      align sources (pure (info 0 9) `branch` [ pure (info 0 1) `leaf` "a", pure (info 2 7) `branch` [ pure (info 4 5) `leaf` "b" ], pure (info 8 9) `leaf` "c" ]) `shouldBe` prettyDiff sources
        [ Join (These (info 0 8 `branch` [ info 0 1 `leaf` "a", info 2 7 `branch` [ info 4 5 `leaf` "b" ] ])
                      (info 0 4 `branch` [ info 0 1 `leaf` "a", info 2 4 `branch` [] ]))
        , Join (That  (info 4 6 `branch` [ info 4 6 `branch` [ info 4 5 `leaf` "b" ] ]))
        , Join (That  (info 6 8 `branch` [ info 6 7 `branch` [] ]))
        , Join (These (info 8 9 `branch` [ info 8 9 `leaf` "c" ])
                      (info 8 9 `branch` [ info 8 9 `leaf` "c" ]))
        ]

  describe "numberedRows" $
    prop "counts only non-empty values" $
      \ xs -> counts (numberedRows (xs :: [Join These Char])) `shouldBe` length . catMaybes <$> Join (unalign (runJoin <$> xs))

data BranchElement
  = Child String (Join These String)
  | Margin (Join These String)
  deriving Show

branchElementKey :: BranchElement -> Maybe String
branchElementKey (Child key _) = Just key
branchElementKey _ = Nothing

toAlignBranchInputs :: [BranchElement] -> (Both (Source.Source Char), [(String, [Join These Range])], Both [Range])
toAlignBranchInputs elements = (sources, join . (`evalState` both 0 0) . traverse go $ elements, ranges)
  where go :: BranchElement -> State (Both Int) [(String, [Join These Range])]
        go child@(Child key _) = do
          lines <- traverse (\ (Child _ contents) -> do
            prev <- get
            let next = (+) <$> prev <*> modifyJoin (fromThese 0 0) (length <$> contents)
            put next
            pure $! modifyJoin (runBothWith bimap (const <$> (Range <$> prev <*> next))) contents) (alignBranchElement child)
          pure [ (key, lines) ]
        go (Margin contents) = do
          prev <- get
          put $ (+) <$> prev <*> modifyJoin (fromThese 0 0) (length <$> contents)
          pure []
        alignBranchElement element = case element of
          Child key contents -> Child key <$> crosswalk lines contents
          Margin contents -> Margin <$> crosswalk lines contents
          where lines = fmap toList . Source.actualLines . Source.fromList
        sources = foldMap Source.fromList <$> bothContents elements
        ranges = fmap (filter (\ (Range start end) -> start /= end)) $ Source.actualLineRanges <$> (totalRange <$> sources) <*> sources
        bothContents = foldMap (modifyJoin (fromThese [] []) . fmap (:[]) . branchElementContents)
        branchElementContents (Child _ contents) = contents
        branchElementContents (Margin contents) = contents

keysOfAlignedChildren :: [Join These (Range, [(String, Range)])] -> [String]
keysOfAlignedChildren lines = lines >>= these identity identity (++) . runJoin . fmap (fmap Prologue.fst . Prologue.snd)

instance Arbitrary BranchElement where
  arbitrary = oneof [ key >>= \ key -> Child key <$> joinTheseOf (contents key)
                    , Margin <$> joinTheseOf margin ]
    where key = listOf1 (elements (['a'..'z'] ++ ['A'..'Z'] ++ ['0'..'9']))
          contents key = wrap key <$> listOf (padding '*')
          wrap key contents = "(" ++ key ++ contents ++ ")" :: String
          margin = listOf (padding '-')
          padding char = frequency [ (10, pure char)
                                   , (1, pure '\n') ]
          joinTheseOf g = oneof [ Join . This <$> g
                                , Join . That <$> g
                                , (Join .) . These <$> g <*> g ]

  shrink (Child key contents) = Child key <$> crosswalk shrinkContents contents
    where shrinkContents string = (++ suffix) . (prefix ++) <$> shrinkList (const []) (drop (length prefix) (take (length string - length suffix) string))
          (prefix, suffix) = ('(' : key, ")" :: String)
  shrink (Margin contents) = Margin <$> crosswalk (shrinkList (const [])) contents

counts :: [Join These (Int, a)] -> Both Int
counts numbered = fromMaybe 0 . getLast . mconcat . fmap Last <$> Join (unalign (runJoin . fmap Prologue.fst <$> numbered))

align :: Both (Source.Source Char) -> ConstructibleFree (Patch (Term String Info)) (Both Info) -> PrettyDiff (SplitDiff String Info)
align sources = PrettyDiff sources . fmap (fmap (getRange &&& identity)) . alignDiff sources . deconstruct

info :: Int -> Int -> Info
info = ((\ r -> Info r mempty 0) .) . Range

prettyDiff :: Both (Source.Source Char) -> [Join These (ConstructibleFree (SplitPatch (Term String Info)) Info)] -> PrettyDiff (SplitDiff String Info)
prettyDiff sources = PrettyDiff sources . fmap (fmap ((getRange &&& identity) . deconstruct))

data PrettyDiff a = PrettyDiff { unPrettySources :: Both (Source.Source Char), unPrettyLines :: [Join These (Range, a)] }
  deriving Eq

instance Show a => Show (PrettyDiff a) where
  showsPrec _ (PrettyDiff sources lines) = (prettyPrinted ++) -- . ("\n" ++ show lines ++)
    where prettyPrinted = showLine (maximum (0 : (maximum . fmap length <$> shownLines))) <$> shownLines >>= ('\n':)
          shownLines = catMaybes $ toBoth <$> lines
          showLine n line = uncurry ((++) . (++ " | ")) (fromThese (replicate n ' ') (replicate n ' ') (runJoin (pad n <$> line)))
          showDiff (range, _) = filter (/= '\n') . toList . Source.slice range
          pad n string = (++) (take n string) (replicate (max 0 (n - length string)) ' ')
          toBoth them = showDiff <$> them `applyThese` modifyJoin (uncurry These) sources

newtype ConstructibleFree patch annotation = ConstructibleFree { deconstruct :: Free (CofreeF (Syntax String) annotation) patch }


class PatchConstructible p where
  insert :: Term String Info -> p
  delete :: Term String Info -> p

instance PatchConstructible (Patch (Term String Info)) where
  insert = Insert
  delete = Delete

instance PatchConstructible (SplitPatch (Term String Info)) where
  insert = SplitInsert
  delete = SplitDelete

instance PatchConstructible patch => PatchConstructible (ConstructibleFree patch annotation) where
  insert = ConstructibleFree . pure . insert
  delete = ConstructibleFree . pure . delete

class SyntaxConstructible s where
  leaf :: annotation -> String -> s annotation
  branch :: annotation -> [s annotation] -> s annotation

instance SyntaxConstructible (ConstructibleFree patch) where
  leaf info = ConstructibleFree . free . Free . (info :<) . Leaf
  branch info = ConstructibleFree . free . Free . (info :<) . Indexed . fmap deconstruct

instance SyntaxConstructible (Cofree (Syntax String)) where
  info `leaf` value = cofree $ info :< Leaf value
  info `branch` children = cofree $ info :< Indexed children