simplify types, make changed char have new format

need to uncomment tests

package.yaml

@@ -32,6 +32,7 @@ dependencies:
   - http-types == 0.12.*
   - memory == 0.18.*
   - mtl == 2.3.*
+  - myers-diff >= 0.2.0.0
   - network >= 3.1.2.7 && < 3.2
   - optparse-applicative >= 0.15 && < 0.17
   - process == 1.6.*

simplex-chat.cabal

@@ -34,6 +34,7 @@ library
       Simplex.Chat.Core
       Simplex.Chat.Help
       Simplex.Chat.Markdown
+      Simplex.Chat.MarkdownDiff
       Simplex.Chat.Messages
       Simplex.Chat.Messages.CIContent
       Simplex.Chat.Migrations.M20220101_initial
@@ -165,6 +166,7 @@ library
     , http-types ==0.12.*
     , memory ==0.18.*
     , mtl ==2.3.*
+    , myers-diff >= 0.2.0.0
     , network >=3.1.2.7 && <3.2
     , optparse-applicative >=0.15 && <0.17
     , process ==1.6.*
@@ -213,6 +215,7 @@ executable simplex-bot
     , http-types ==0.12.*
     , memory ==0.18.*
     , mtl ==2.3.*
+    , myers-diff >= 0.2.0.0
     , network >=3.1.2.7 && <3.2
     , optparse-applicative >=0.15 && <0.17
     , process ==1.6.*
@@ -262,6 +265,7 @@ executable simplex-bot-advanced
     , http-types ==0.12.*
     , memory ==0.18.*
     , mtl ==2.3.*
+    , myers-diff >= 0.2.0.0
     , network >=3.1.2.7 && <3.2
     , optparse-applicative >=0.15 && <0.17
     , process ==1.6.*
@@ -313,6 +317,7 @@ executable simplex-broadcast-bot
     , http-types ==0.12.*
     , memory ==0.18.*
     , mtl ==2.3.*
+    , myers-diff >= 0.2.0.0
     , network >=3.1.2.7 && <3.2
     , optparse-applicative >=0.15 && <0.17
     , process ==1.6.*
@@ -363,6 +368,7 @@ executable simplex-chat
     , http-types ==0.12.*
     , memory ==0.18.*
     , mtl ==2.3.*
+    , myers-diff >= 0.2.0.0
     , network ==3.1.*
     , optparse-applicative >=0.15 && <0.17
     , process ==1.6.*
@@ -453,6 +459,7 @@ test-suite simplex-chat-test
       ChatTests.Profiles
       ChatTests.Utils
       MarkdownTests
+      MarkdownDiffTests
       MobileTests
       ProtocolTests
       SchemaDump
@@ -492,6 +499,7 @@ test-suite simplex-chat-test
     , http-types ==0.12.*
     , memory ==0.18.*
     , mtl ==2.3.*
+    , myers-diff >= 0.2.0.0
     , network ==3.1.*
     , optparse-applicative >=0.15 && <0.17
     , process ==1.6.*

src/Simplex/Chat/Markdown.hs

@@ -17,7 +17,7 @@ import qualified Data.Attoparsec.Text as A
 import Data.Char (isDigit)
 import Data.Either (fromRight)
 import Data.Functor (($>))
-import Data.List (intercalate, foldl')
+import Data.List (foldl', intercalate)
 import Data.List.NonEmpty (NonEmpty)
 import qualified Data.List.NonEmpty as L
 import Data.Maybe (fromMaybe, isNothing)
@@ -51,8 +51,16 @@ data Format
   | SimplexLink {linkType :: SimplexLinkType, simplexUri :: Text, trustedUri :: Bool, smpHosts :: NonEmpty Text}
   | Email
   | Phone
+  | Edited EditAction Format
   deriving (Eq, Show, Generic)
 
+data EditAction = EAInsert | EADelete | EAChangeFormat
+  deriving (Eq, Show, Generic)
+
+instance ToJSON EditAction where
+  toJSON = J.genericToJSON . enumJSON $ dropPrefix "EA"
+  toEncoding = J.genericToEncoding . enumJSON $ dropPrefix "EA"
+
 data SimplexLinkType = XLContact | XLInvitation | XLGroup
   deriving (Eq, Show, Generic)
 
@@ -129,7 +137,7 @@ parseMaybeMarkdownList s
   | otherwise = Just . reverse $ foldl' acc [] ml
   where
     ml = intercalate ["\n"] . map (markdownToList . parseMarkdown) $ T.lines s
-    acc [] m = [m] 
+    acc [] m = [m]
     acc ms@(FormattedText f t : ms') ft@(FormattedText f' t')
       | f == f' = FormattedText f (t <> t') : ms'
       | otherwise = ft : ms
@@ -170,14 +178,14 @@ markdownP = mconcat <$> A.many' fragmentP
     md :: Char -> Format -> Text -> Markdown
     md c f s
       | T.null s || T.head s == ' ' || T.last s == ' ' =
-        unmarked $ c `T.cons` s `T.snoc` c
+          unmarked $ c `T.cons` s `T.snoc` c
       | otherwise = markdown f s
     secretP :: Parser Markdown
     secretP = secret <$> A.takeWhile (== '#') <*> A.takeTill (== '#') <*> A.takeWhile (== '#')
     secret :: Text -> Text -> Text -> Markdown
     secret b s a
       | T.null a || T.null s || T.head s == ' ' || T.last s == ' ' =
-        unmarked $ '#' `T.cons` ss
+          unmarked $ '#' `T.cons` ss
       | otherwise = markdown Secret $ T.init ss
       where
         ss = b <> s <> a
@@ -218,8 +226,8 @@ markdownP = mconcat <$> A.many' fragmentP
     wordMD s
       | T.null s = unmarked s
       | isUri s = case strDecode $ encodeUtf8 s of
-        Right cReq -> markdown (simplexUriFormat cReq) s
-        _ -> markdown Uri s
+          Right cReq -> markdown (simplexUriFormat cReq) s
+          _ -> markdown Uri s
       | isEmail s = markdown Email s
       | otherwise = unmarked s
     isUri s = T.length s >= 10 && any (`T.isPrefixOf` s) ["http://", "https://", "simplex:/"]

src/Simplex/Chat/MarkdownDiff.hs

@@ -0,0 +1,136 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+{-# HLINT ignore "Use newtype instead of data" #-}
+
+module Simplex.Chat.MarkdownDiff
+  ( DiffChar (..),
+    DiffPlainChar (..),
+    DiffFormatStatus (..),
+    FormatChar (..),
+    diff,
+    plainDiff,
+  )
+where
+
+import qualified Data.Diff.Myers as D
+import qualified Data.Foldable as F
+import Data.Map.Strict (Map)
+import qualified Data.Map.Strict as M
+import Data.Sequence (Seq (..), (><))
+import qualified Data.Sequence as S
+import qualified Data.Text as T
+import Simplex.Chat.Markdown (EditAction (..), Format)
+
+data DiffFormatStatus
+  = UnchangedFormat
+  | ChangedToFormat (Maybe Format)
+  deriving (Show, Eq)
+
+data DiffChar = DiffChar FormatChar (Maybe EditAction)
+  deriving (Show, Eq)
+
+data DiffPlainChar = DiffPlainChar Char (Maybe EditAction)
+  deriving (Show, Eq)
+
+data FormatChar = FormatChar
+  { char :: Char,
+    format :: Maybe Format
+  }
+  deriving (Show, Eq)
+
+newtype DeleteIndices = DeleteIndices (Seq Int) deriving (Show, Eq)
+
+newtype InsertIndices = InsertIndices (Seq Int) deriving (Show, Eq)
+
+plainDiff :: T.Text -> T.Text -> Seq DiffPlainChar
+plainDiff left right = toPlain <$> formattedDiff
+  where
+    formattedDiff = diff (toFormatted left) (toFormatted right)
+    toPlain :: DiffChar -> DiffPlainChar
+    toPlain (DiffChar (FormatChar c _) editAction) = DiffPlainChar c editActionPlain
+      where
+        editActionPlain = case editAction of
+          Just EAInsert -> Just EAInsert
+          Just EADelete -> Just EADelete
+          Just EAChangeFormat -> Nothing
+          Nothing -> Nothing
+
+    toFormatted :: T.Text -> Seq FormatChar
+    toFormatted = fmap (`FormatChar` Nothing) . S.fromList . T.unpack
+
+diff :: Seq FormatChar -> Seq FormatChar -> Seq DiffChar
+diff left right = addInserts markDeletesAndUnchangedChars
+  where
+    edits = D.diffTexts (toText left) (toText right)
+    (DeleteIndices deleteIndicies, InsertIndices insertIndicies) = indices
+
+    toText :: Seq FormatChar -> T.Text
+    toText = T.pack . F.toList . fmap char
+
+    indices :: (DeleteIndices, InsertIndices)
+    indices = F.foldl' f (DeleteIndices S.empty, InsertIndices S.empty) edits
+      where
+        f :: (DeleteIndices, InsertIndices) -> D.Edit -> (DeleteIndices, InsertIndices)
+        f (x@(DeleteIndices ds), y@(InsertIndices is)) e = case e of
+          D.EditDelete m n -> (x', y) where x' = DeleteIndices $ ds >< S.fromList [m .. n]
+          D.EditInsert _ m n -> (x, y') where y' = InsertIndices $ is >< S.fromList [m .. n]
+
+    unchangedChars :: Map Int DiffFormatStatus -- indexed in left
+    unchangedChars = F.foldl' f mempty unchangedCharPairs
+      where
+        unchangedCharPairs :: Seq (Int, FormatChar, FormatChar)
+        unchangedCharPairs = g <$> S.zip leftWithoutDeletes rightWithoutInserts
+
+        leftWithoutDeletes :: Seq (Int, FormatChar)
+        leftWithoutDeletes =
+          S.filter (\(i, _) -> i `notElem` deleteIndicies) $
+            S.zip (S.fromList [0 .. S.length left - 1]) left
+
+        rightWithoutInserts :: Seq (Int, FormatChar)
+        rightWithoutInserts =
+          S.filter (\(i, _) -> i `notElem` insertIndicies) $
+            S.zip (S.fromList [0 .. S.length right - 1]) right
+
+        f :: Map Int DiffFormatStatus -> (Int, FormatChar, FormatChar) -> Map Int DiffFormatStatus
+        f acc (i, FormatChar _ fL, FormatChar _ fR) = M.insert i x acc
+          where
+            x = if fL == fR then UnchangedFormat else ChangedToFormat fR
+
+        g :: ((Int, FormatChar), (Int, FormatChar)) -> (Int, FormatChar, FormatChar)
+        g ((i, c), (_, d)) = (i, c, d)
+
+    markDeletesAndUnchangedChars :: Seq DiffChar
+    markDeletesAndUnchangedChars = S.mapWithIndex f left
+      where
+        f :: Int -> FormatChar -> DiffChar
+        f i x@(FormatChar c _)
+          | i `elem` deleteIndicies = DiffChar x (Just EADelete)
+          | otherwise = case unchangedChars M.! i of -- should never error
+              UnchangedFormat -> DiffChar x Nothing
+              ChangedToFormat f' -> DiffChar (FormatChar c f') (Just EAChangeFormat)
+    addInserts :: Seq DiffChar -> Seq DiffChar
+    addInserts base = F.foldr f base edits -- start from end and work backwards, hence foldr
+      where
+        f :: D.Edit -> Seq DiffChar -> Seq DiffChar
+        f e acc = case e of
+          D.EditDelete _ _ -> acc
+          D.EditInsert i m n -> S.take i' acc >< inserts >< S.drop i' acc
+            where
+              -- D.EditInsert i m n -> S.take i  acc >< inserts >< S.drop i  acc
+              -- if ok to have inserts before deletes, use i not i'
+              -- Using i of course is faster, but perhaps i' approach can be optimised
+
+              i' = slidePastDeleteBlock i
+
+              slidePastDeleteBlock :: Int -> Int
+              slidePastDeleteBlock x = case S.lookup x acc of
+                Nothing -> x
+                Just (DiffChar _ diffStatus) ->
+                  if diffStatus == Just EADelete
+                    then slidePastDeleteBlock (x + 1)
+                    else x
+
+              rightFormatChars = S.take (n - m + 1) $ S.drop m right
+              inserts = fmap (`DiffChar` Just EAInsert) rightFormatChars

tests/MarkdownDiffTests.hs

@@ -0,0 +1,334 @@
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module MarkdownDiffTests where
+
+import qualified Data.List.NonEmpty as NE
+import Simplex.Chat.Markdown
+import Simplex.Chat.MarkdownDiff
+import System.Console.ANSI.Types
+import Test.Hspec
+
+markdownDiffTests :: Spec
+markdownDiffTests = do
+  formattedEditedTextTests
+
+formattedEditedTextTests :: Spec
+formattedEditedTextTests = describe "show edits" do
+  it "empty no change" $
+    diff [] [] `shouldBe` []
+  it "no change" $
+    diff [FormatChar 'H' Nothing] [FormatChar 'H' Nothing]
+      `shouldBe` [DiffChar (FormatChar 'H' Nothing) Nothing]
+  it "add 1 char to empty" $
+    diff [] [FormatChar 'H' Nothing]
+      `shouldBe` [DiffChar (FormatChar 'H' Nothing) $ Just EAInsert]
+  it "del the one and only" $
+    diff [FormatChar 'H' Nothing] []
+      `shouldBe` [DiffChar (FormatChar 'H' Nothing) $ Just EADelete]
+  it "one character change" do
+    diff
+      [ FormatChar 'H' Nothing,
+        FormatChar 'r' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' Nothing
+      ]
+      [ FormatChar 'H' Nothing,
+        FormatChar 'e' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' Nothing
+      ]
+      `shouldBe` [ DiffChar (FormatChar 'H' Nothing) Nothing,
+                   DiffChar (FormatChar 'r' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'e' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'l' Nothing) Nothing,
+                   DiffChar (FormatChar 'l' Nothing) Nothing,
+                   DiffChar (FormatChar 'o' Nothing) Nothing
+                 ]
+
+  it "more1" do
+    diff
+      [ FormatChar 'H' Nothing,
+        FormatChar 'r' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' Nothing
+      ]
+      [ FormatChar 'H' Nothing,
+        FormatChar 'e' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' Nothing,
+        FormatChar 'x' Nothing,
+        FormatChar 'y' Nothing,
+        FormatChar 'z' Nothing
+      ]
+      `shouldBe` [ DiffChar (FormatChar 'H' Nothing) Nothing,
+                   DiffChar (FormatChar 'r' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'e' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'l' Nothing) Nothing,
+                   DiffChar (FormatChar 'l' Nothing) Nothing,
+                   DiffChar (FormatChar 'o' Nothing) Nothing,
+                   DiffChar (FormatChar 'x' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'y' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'z' Nothing) $ Just EAInsert
+                 ]
+
+  it "more2" do
+    diff
+      [ FormatChar 'H' Nothing,
+        FormatChar 'r' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' Nothing
+      ]
+      [ FormatChar 'H' Nothing,
+        FormatChar 'e' Nothing,
+        FormatChar 'x' Nothing,
+        FormatChar 'y' Nothing,
+        FormatChar 'z' Nothing,
+        FormatChar 'o' Nothing
+      ]
+      `shouldBe` [ DiffChar (FormatChar 'H' Nothing) Nothing,
+                   DiffChar (FormatChar 'r' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'l' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'l' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'e' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'x' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'y' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'z' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'o' Nothing) Nothing
+                 ]
+
+  it "more3" do
+    diff
+      [ FormatChar 'H' $ Just Bold,
+        FormatChar 'H' $ Just Bold,
+        FormatChar 'r' Nothing,
+        FormatChar 'l' $ Just Secret,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' $ Just $ colored Green
+      ]
+      [ FormatChar 'H' $ Just Italic,
+        FormatChar 'H' $ Just Bold,
+        FormatChar 'e' $ Just $ colored Cyan,
+        FormatChar 'x' Nothing,
+        FormatChar 'y' Nothing,
+        FormatChar 'z' $ Just Secret,
+        FormatChar 'o' $ Just $ colored Blue
+      ]
+      `shouldBe` [ DiffChar (FormatChar 'H' (Just Italic)) (Just EAChangeFormat),
+                   DiffChar (FormatChar 'H' (Just Bold)) Nothing,
+                   DiffChar (FormatChar 'r' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'l' (Just Secret)) $ Just EADelete,
+                   DiffChar (FormatChar 'l' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'e' (Just $ colored Cyan)) $ Just EAInsert,
+                   DiffChar (FormatChar 'x' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'y' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'z' (Just Secret)) $ Just EAInsert,
+                   DiffChar (FormatChar 'o' (Just $ colored Blue)) (Just EAChangeFormat)
+                 ]
+
+  it "more4" do
+    diff
+      [ FormatChar 'H' Nothing,
+        FormatChar 'r' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar '~' Nothing,
+        FormatChar '!' Nothing,
+        FormatChar '@' Nothing,
+        FormatChar 'l' Nothing,
+        FormatChar 'o' Nothing
+      ]
+      [ FormatChar 'H' Nothing,
+        FormatChar 'e' Nothing,
+        FormatChar 'r' Nothing,
+        FormatChar 'x' Nothing,
+        FormatChar 'y' Nothing,
+        FormatChar '!' Nothing,
+        FormatChar '@' Nothing,
+        FormatChar 'z' Nothing,
+        FormatChar 'o' Nothing,
+        FormatChar '1' Nothing,
+        FormatChar '2' Nothing
+      ]
+      `shouldBe` [ DiffChar (FormatChar 'H' Nothing) Nothing,
+                   DiffChar (FormatChar 'e' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'r' Nothing) Nothing,
+                   DiffChar (FormatChar 'l' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar '~' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'x' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'y' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar '!' Nothing) Nothing,
+                   DiffChar (FormatChar '@' Nothing) Nothing,
+                   DiffChar (FormatChar 'l' Nothing) $ Just EADelete,
+                   DiffChar (FormatChar 'z' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar 'o' Nothing) Nothing,
+                   DiffChar (FormatChar '1' Nothing) $ Just EAInsert,
+                   DiffChar (FormatChar '2' Nothing) $ Just EAInsert
+                 ]
+
+  it "SimplexLink 1" do
+    diff
+      [ FormatChar '>' $
+          Just $
+            SimplexLink
+              { linkType = XLContact,
+                simplexUri = "https://api.twitter.com/2/tweets/:id",
+                trustedUri = True,
+                smpHosts = NE.fromList ["host1", "host2", "host3"]
+              }
+      ]
+      [ FormatChar '>' $
+          Just
+            SimplexLink
+              { linkType = XLContact,
+                simplexUri = "https://api.twitter.com/3/tweets/:id",
+                trustedUri = True,
+                smpHosts = NE.fromList ["host0", "host2", "host3"]
+              }
+      ]
+      `shouldBe` [ DiffChar
+                     ( FormatChar '>' $
+                         Just
+                           SimplexLink
+                             { linkType = XLContact,
+                               simplexUri = "https://api.twitter.com/3/tweets/:id",
+                               trustedUri = True,
+                               smpHosts = NE.fromList ["host0", "host2", "host3"]
+                             }
+                     )
+                     (Just EAChangeFormat)
+                 ]
+
+  it "SimplexLink 2" do
+    diff
+      [ FormatChar '>' $
+          Just $
+            SimplexLink
+              { linkType = XLContact,
+                simplexUri = "https://api.twitter.com/2/tweets/:id",
+                trustedUri = True,
+                smpHosts = NE.fromList ["host1", "host2", "host3"]
+              }
+      ]
+      [ FormatChar '>' $
+          Just
+            SimplexLink
+              { linkType = XLContact,
+                simplexUri = "https://api.twitter.com/3/tweets/:id",
+                trustedUri = True,
+                smpHosts = NE.fromList ["host1", "host2", "host3"]
+              }
+      ]
+      `shouldBe` [ DiffChar
+                     ( FormatChar '>' $
+                         Just
+                           SimplexLink
+                             { linkType = XLContact,
+                               simplexUri = "https://api.twitter.com/3/tweets/:id",
+                               trustedUri = True,
+                               smpHosts = NE.fromList ["host1", "host2", "host3"]
+                             }
+                     )
+                     (Just EAChangeFormat)
+                 ]
+
+  it "SimplexLink 3" do
+    diff
+      [ FormatChar '>' $
+          Just $
+            SimplexLink
+              { linkType = XLContact,
+                simplexUri = "https://api.twitter.com/2/tweets/:id",
+                trustedUri = True,
+                smpHosts = NE.fromList ["host1", "host2", "host3"]
+              }
+      ]
+      [ FormatChar '>' $
+          Just
+            SimplexLink
+              { linkType = XLContact,
+                simplexUri = "https://api.twitter.com/2/tweets/:id",
+                trustedUri = True,
+                smpHosts = NE.fromList ["host0", "host2", "host3"]
+              }
+      ]
+      `shouldBe` [ DiffChar
+                     ( FormatChar '>' $
+                         Just
+                           SimplexLink
+                             { linkType = XLContact,
+                               simplexUri = "https://api.twitter.com/2/tweets/:id",
+                               trustedUri = True,
+                               smpHosts = NE.fromList ["host0", "host2", "host3"]
+                             }
+                     )
+                     (Just EAChangeFormat)
+                 ]
+
+  it "plainDiff 1" do
+    plainDiff
+      "https://api.twitter.com/2/tweets/:id"
+      "https://api.twitter.com/3/tweets/:id"
+      `shouldBe` [ DiffPlainChar 'h' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 'p' Nothing,
+                   DiffPlainChar 's' Nothing,
+                   DiffPlainChar ':' Nothing,
+                   DiffPlainChar '/' Nothing,
+                   DiffPlainChar '/' Nothing,
+                   DiffPlainChar 'a' Nothing,
+                   DiffPlainChar 'p' Nothing,
+                   DiffPlainChar 'i' Nothing,
+                   DiffPlainChar '.' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 'w' Nothing,
+                   DiffPlainChar 'i' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 'e' Nothing,
+                   DiffPlainChar 'r' Nothing,
+                   DiffPlainChar '.' Nothing,
+                   DiffPlainChar 'c' Nothing,
+                   DiffPlainChar 'o' Nothing,
+                   DiffPlainChar 'm' Nothing,
+                   DiffPlainChar '/' Nothing,
+                   DiffPlainChar '2' $ Just EADelete,
+                   DiffPlainChar '3' $ Just EAInsert,
+                   DiffPlainChar '/' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 'w' Nothing,
+                   DiffPlainChar 'e' Nothing,
+                   DiffPlainChar 'e' Nothing,
+                   DiffPlainChar 't' Nothing,
+                   DiffPlainChar 's' Nothing,
+                   DiffPlainChar '/' Nothing,
+                   DiffPlainChar ':' Nothing,
+                   DiffPlainChar 'i' Nothing,
+                   DiffPlainChar 'd' Nothing
+                 ]
+
+  it "plainDiff 2" do
+    plainDiff
+      "Hrl~!@lo"
+      "Herxy!@zo12"
+      `shouldBe` [ DiffPlainChar 'H' Nothing,
+                   DiffPlainChar 'e' $ Just EAInsert,
+                   DiffPlainChar 'r' Nothing,
+                   DiffPlainChar 'l' $ Just EADelete,
+                   DiffPlainChar '~' $ Just EADelete,
+                   DiffPlainChar 'x' $ Just EAInsert,
+                   DiffPlainChar 'y' $ Just EAInsert,
+                   DiffPlainChar '!' Nothing,
+                   DiffPlainChar '@' Nothing,
+                   DiffPlainChar 'l' $ Just EADelete,
+                   DiffPlainChar 'z' $ Just EAInsert,
+                   DiffPlainChar 'o' Nothing,
+                   DiffPlainChar '1' $ Just EAInsert,
+                   DiffPlainChar '2' $ Just EAInsert
+                 ]

tests/Test.hs

@@ -5,6 +5,7 @@ import ChatTests
 import ChatTests.Utils (xdescribe'')
 import Control.Logger.Simple
 import Data.Time.Clock.System
+import MarkdownDiffTests
 import MarkdownTests
 import MobileTests
 import ProtocolTests
@@ -20,6 +21,7 @@ main = do
   withGlobalLogging logCfg . hspec $ do
     describe "Schema dump" schemaDumpTest
     describe "SimpleX chat markdown" markdownTests
+    fdescribe "SimpleX chat markdown diff" markdownDiffTests
     describe "SimpleX chat view" viewTests
     describe "SimpleX chat protocol" protocolTests
     describe "WebRTC encryption" webRTCTests