From 360daf2a0904b3d8c2f64034184fe7e95683ef71 Mon Sep 17 00:00:00 2001
From: Julian Ospald <hasufell@posteo.de>
Date: Sat, 30 Oct 2021 12:52:11 +0200
Subject: [PATCH] Make upgrading ghcup in TUI more pleasant

---
 app/ghcup/BrickMain.hs | 37 ++++++++++++++++++++++++++++---------
 ghcup.cabal            |  3 +++
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/app/ghcup/BrickMain.hs b/app/ghcup/BrickMain.hs
index f20428e..37750ca 100644
--- a/app/ghcup/BrickMain.hs
+++ b/app/ghcup/BrickMain.hs
@@ -10,6 +10,7 @@ module BrickMain where
 import           GHCup
 import           GHCup.Download
 import           GHCup.Errors
+import           GHCup.Types.Optics ( getDirs )
 import           GHCup.Types         hiding ( LeanAppState(..) )
 import           GHCup.Utils
 import           GHCup.Utils.Logger
@@ -40,6 +41,8 @@ import           Data.Vector                    ( Vector
 import           Data.Versions           hiding ( str )
 import           Haskus.Utils.Variant.Excepts
 import           Prelude                 hiding ( appendFile )
+import           System.Directory               ( canonicalizePath )
+import           System.FilePath
 import           System.Exit
 import           System.IO.Unsafe
 import           Text.PrettyPrint.HughesPJClass ( prettyShow )
@@ -48,6 +51,8 @@ import           URI.ByteString
 import qualified Data.Text                     as T
 import qualified Graphics.Vty                  as Vty
 import qualified Data.Vector                   as V
+import System.Environment (getExecutablePath)
+import qualified System.Posix.Process          as SPP
 
 
 hiddenTools :: [Tool]
@@ -432,27 +437,42 @@ install' _ (_, ListResult {..}) = do
               ]
 
   run (do
+      ce <- liftIO $ fmap (either (const Nothing) Just) $
+        try @_ @SomeException $ getExecutablePath >>= canonicalizePath
+      dirs <- lift getDirs
       case lTool of
         GHC   -> do
           let vi = getVersionInfo lVer GHC dls
-          liftE $ installGHCBin lVer Nothing False $> vi
+          liftE $ installGHCBin lVer Nothing False $> (vi, dirs, ce)
         Cabal -> do
           let vi = getVersionInfo lVer Cabal dls
-          liftE $ installCabalBin lVer Nothing False $> vi
+          liftE $ installCabalBin lVer Nothing False $> (vi, dirs, ce)
         GHCup -> do
           let vi = snd <$> getLatest dls GHCup
-          liftE $ upgradeGHCup Nothing False $> vi
+          liftE $ upgradeGHCup Nothing False $> (vi, dirs, ce)
         HLS   -> do
           let vi = getVersionInfo lVer HLS dls
-          liftE $ installHLSBin lVer Nothing False $> vi
+          liftE $ installHLSBin lVer Nothing False $> (vi, dirs, ce)
         Stack -> do
           let vi = getVersionInfo lVer Stack dls
-          liftE $ installStackBin lVer Nothing False $> vi
+          liftE $ installStackBin lVer Nothing False $> (vi, dirs, ce)
     )
     >>= \case
-          VRight vi                         -> do
-            forM_ (_viPostInstall =<< vi) $ \msg ->
-              logInfo msg
+          VRight (vi, Dirs{..}, Just ce) -> do
+            forM_ (_viPostInstall =<< vi) $ \msg -> logInfo msg
+            case lTool of
+              GHCup -> do
+                up <- liftIO $ fmap (either (const Nothing) Just)
+                  $ try @_ @SomeException $ canonicalizePath (binDir </> "ghcup" <.> exeExt)
+                when ((normalise <$> up) == Just (normalise ce)) $
+                  -- TODO: track cli arguments of previous invocation
+                  liftIO $ SPP.executeFile ce False ["tui"] Nothing
+                logInfo "Please restart 'ghcup' for the changes to take effect"
+              _ -> pure ()
+            pure $ Right ()
+          VRight (vi, _, _) -> do
+            forM_ (_viPostInstall =<< vi) $ \msg -> logInfo msg
+            logInfo "Please restart 'ghcup' for the changes to take effect"
             pure $ Right ()
           VLeft  (V (AlreadyInstalled _ _)) -> pure $ Right ()
           VLeft (V NoUpdate) -> pure $ Right ()
@@ -605,4 +625,3 @@ getAppData mgi = runExceptT $ do
   flip runReaderT settings $ do
     lV <- listVersions Nothing Nothing
     pure $ BrickData (reverse lV)
-
diff --git a/ghcup.cabal b/ghcup.cabal
index 0cf2fb7..735b9f1 100644
--- a/ghcup.cabal
+++ b/ghcup.cabal
@@ -224,6 +224,7 @@ executable ghcup
     , cabal-plan            ^>=0.7.2
     , containers            ^>=0.6
     , deepseq               ^>=1.4
+    , directory             ^>=1.3.6.0
     , filepath              ^>=1.4.2.1
     , ghcup
     , haskus-utils-variant  >=3.0      && <3.2
@@ -252,11 +253,13 @@ executable ghcup
     build-depends:
       , brick         ^>=0.64
       , transformers  ^>=0.5
+      , unix          ^>=2.7
       , vector        ^>=0.12
       , vty           >=5.28.2 && <5.34
 
   if os(windows)
     cpp-options: -DIS_WINDOWS
+
   if flag(no-exe)
     buildable: False