made ytdl function way prettier

src/YTDL.hs

@@ -3,7 +3,6 @@ module YTDL (Resolution(..), ytdl) where
 import Config
 
 import Control.Monad.Trans.Reader
-import Control.Monad.Trans.Class
 import Control.Concurrent (forkIO, threadDelay)
 import Data.Digest.Pure.MD5
 import qualified Data.ByteString.Lazy.UTF8 as BCU
@@ -37,8 +36,7 @@ resToArgs (PMAX)  = ["-f", "bestvideo[ext=mp4]+bestaudio[ext=m4a]/mp4", "--merge
 resToArgs (Audio) = ["-x", "--audio-format", "mp3"]
 
 ytdl :: String -> Resolution -> ReaderT ViddlConfig IO (Either String FilePath)
-ytdl url res = do
-  cfg <- ask
+ytdl url res = ReaderT $ \cfg -> do
 
   let ext = case res of { Audio -> ".mp3"; _ -> ".mp4" }
 
@@ -47,30 +45,30 @@ ytdl url res = do
   let dir = concat [dlDir cfg, "/", ident]
   let fileName = concat [dir, "/", ident, ext]
 
-  processed <- lift $ doesFileExist fileName
+  processed <- doesFileExist fileName
   if processed
     then do
-      lift $ putStrLn $ "Returning existing ident " <> ident
+      putStrLn $ "Returning existing ident " <> ident
       pure (Right fileName)
     else do
-      lift $ putStrLn $ "Processing new ident " <> ident
+      putStrLn $ "Processing new ident " <> ident
 
-      lift $ createDirectoryIfMissing True dir
+      createDirectoryIfMissing True dir
 
-      lift $ print (resToArgs res <> ["-o", fileName, url])
+      print (resToArgs res <> ["-o", fileName, url])
 
-      ytdlProc <- lift $ createProcess (proc "youtube-dl" (resToArgs res <> ["-o", fileName, url]))
+      ytdlProc <- createProcess (proc "youtube-dl" (resToArgs res <> ["-o", fileName, url]))
 
       case ytdlProc of
         (_, _, _, ph) -> do
-          exitCode <- lift $ waitForProcess ph
+          exitCode <- waitForProcess ph
           case exitCode of
             ExitSuccess -> do
-              exists <- lift $ doesFileExist fileName
+              exists <- doesFileExist fileName
               if exists
                 then do
                   -- wait 5 minutes and then delete the directory
-                  _ <- lift $ forkIO $ threadDelay 300000000 >> removeDirectoryRecursive dir
+                  _ <- forkIO $ threadDelay 300000000 >> removeDirectoryRecursive dir
                   pure (Right fileName)
                 else do 
                   -- removeDirectoryRecursive dir