From d11e3fcfa5a048a33854a7c77d5a0d7bb8804a68 Mon Sep 17 00:00:00 2001
From: Ali Abrar <ali.abrar@obsidian.systems>
Date: Mon, 24 Jul 2023 11:36:19 -0400
Subject: [PATCH] Add option to convert pre/post qualified

---
 app/Main.hs        | 37 ++++++++++++++++++++++++++++---------
 src/SortImports.hs | 22 +++++++++++++---------
 2 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/app/Main.hs b/app/Main.hs
index 58d046b..89f0cdb 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -6,23 +6,29 @@ import Options.Applicative
 import SortImports (sortImports)
 import System.Environment (getArgs)
 import System.IO (hReady, stdin)
+import SortImports.Types (Qualified(..))
 
 versionNumber :: String
 versionNumber = "v1.2.0"
 
-version :: Parser Options
+version :: Parser Mode
 version = flag' Version $ mconcat
   [ long "version"
   , short 'v'
   , help "Version number"
   ]
 
-data Options
+data Mode
   = Version
   | FileInput FilePath
   | StdInput
 
-fileInput :: Parser Options
+data Options = Options
+  { _options_mode :: Mode
+  , _options_convert :: Maybe Qualified
+  }
+
+fileInput :: Parser Mode
 fileInput = FileInput <$> strOption (mconcat
   [ long "file"
   , short 'f'
@@ -30,27 +36,40 @@ fileInput = FileInput <$> strOption (mconcat
   , help "Input file"
   ])
 
-stdInput :: Parser Options
+stdInput :: Parser Mode
 stdInput = flag' StdInput $ mconcat
   [ long "stdin"
   , help "Read input from stdin"
   ]
 
+convertToQualifiedPost :: Parser Bool
+convertToQualifiedPost = switch (long "convert-to-qualified-post" <> help "Whether to convert all qualified imports to use ImportQualifiedPost")
+
+convertToQualifiedPre :: Parser Bool
+convertToQualifiedPre = switch (long "convert-to-qualified-pre" <> help "Whether to convert all ImportQualifiedPost imports to use older \"import qualified\" syntax")
+
 options :: Parser Options
-options = version <|> fileInput <|> stdInput
+options = Options
+  <$> (version <|> fileInput <|> stdInput)
+  <*> (post <|> pre)
+  where
+    post = ((\x -> if x then Just Qualified_Post else Nothing) <$> convertToQualifiedPost)
+    pre = ((\x -> if x then Just Qualified_Pre else Nothing) <$> convertToQualifiedPre)
 
 run :: Options -> IO ()
-run = \case
+run opts = case _options_mode opts of
   Version        -> putStrLn versionNumber
-  FileInput path -> readFile path >>= putStr . sortImports
-  StdInput       -> interact sortImports
+  FileInput path -> readFile path >>= putStr . (sortImports convert)
+  StdInput       -> interact (sortImports convert)
+  where
+    convert = _options_convert opts
 
 main :: IO ()
 main = do
   noArgs   <- null <$> getArgs
   anyStdin <- hReady stdin
   if noArgs && anyStdin
-    then run StdInput
+    then run (Options StdInput Nothing)
     else execParser opts >>= run
   where opts = info (options <**> helper) $ mconcat
           [ briefDesc
diff --git a/src/SortImports.hs b/src/SortImports.hs
index b039e11..73d3232 100644
--- a/src/SortImports.hs
+++ b/src/SortImports.hs
@@ -93,8 +93,8 @@ exposure = do
   hiding <- isJust <$> optional (rword "hiding")
   (if hiding then Hidden else Exposed) <$> exports
 
-module' :: Parser Module
-module' = do
+module' :: Maybe Qualified -> Parser Module
+module' cfgQualified = do
   void $ rword "import"
   _qualified' <- isJust <$> optional (rword "qualified")
   _name      <- moduleName
@@ -102,15 +102,19 @@ module' = do
   _alias     <- optional alias
   _exports   <- optional exposure
   space
-  let _qualified = if _qualified' then Just Qualified_Pre else if _qualified'' then Just Qualified_Post else Nothing
+  let _qualified = case cfgQualified of
+        Nothing -> if _qualified'
+          then Just Qualified_Pre
+          else if _qualified'' then Just Qualified_Post else Nothing
+        Just q -> if (_qualified' || _qualified'') then Just q else Nothing
   pure Module {..}
 
 sortExports :: Module -> Module
 sortExports m = m { _exports = fmap sort <$> _exports m }
 
-lineType :: String -> LineType
-lineType x =
-  case parse module' "" x of
+lineType :: Maybe Qualified -> String -> LineType
+lineType mq x =
+  case parse (module' mq) "" x of
     Left  _ -> CodeLine x
     Right m -> ModuleLine m
 
@@ -127,12 +131,12 @@ sortIfModules xs@(ModuleLine _:_) = sort . fmap f $ xs
   where f (ModuleLine x) = ModuleLine $ sortExports x
         f x = x
 
-sortImports :: String -> String
-sortImports
+sortImports :: Maybe Qualified -> String -> String
+sortImports mq
   = unlines
   . fmap (\case CodeLine x -> x
                 ModuleLine x -> view x)
   . concatMap sortIfModules
   . groupLines
-  . map lineType
+  . map (lineType mq)
   . lines