Fix cursor movement to avoid updating wrong lines

- Remove save/restore cursor in favor of explicit movement - Always
move up from bottom position, update line, move back down - Simplify
initializeLines to just print lines sequentially - Cursor now stays
at bottom and moves up/down for each update - Fixes issue where lines
were being updated far up the terminal

1 files changed, 12 insertions, 11 deletions

diff --git a/Omni/Log/Concurrent.hs b/Omni/Log/Concurrent.hs
index 4654365..86a3853 100644
--- a/Omni/Log/Concurrent.hs
+++ b/Omni/Log/Concurrent.hs
@@ -88,15 +88,12 @@ initializeLines :: LineManager -> IO ()
 initializeLines LineManager {..} =
   when lmSupportsANSI <| do
     nsMap <- readIORef namespaceLines
-    forM_ (Map.toList nsMap) <| \(ns, lineNum) -> do
-      ANSI.hSaveCursor IO.stderr
+    forM_ (Map.toList nsMap) <| \(ns, _) -> do
       ANSI.hSetCursorColumn IO.stderr 0
-      when (lineNum > 0) <| ANSI.hCursorDown IO.stderr lineNum
       ANSI.hClearLine IO.stderr
       let nsText = Text.pack (Namespace.toPath ns)
-      IO.hPutStr IO.stderr (Text.unpack <| "[…] " <> nsText)
+      IO.hPutStrLn IO.stderr (Text.unpack <| "[…] " <> nsText)
       IO.hFlush IO.stderr
-      ANSI.hRestoreCursor IO.stderr
 
 updateLine :: Namespace -> Text -> IO ()
 updateLine ns output = do
@@ -115,15 +112,17 @@ updateLine ns output = do
           case Map.lookup ns nsMap of
             Nothing -> pure ()
             Just lineNum -> do
-              ANSI.hSaveCursor IO.stderr
+              let numLines = length lmNamespaces
+              -- Move to the target line from bottom
+              ANSI.hCursorUp IO.stderr (numLines - lineNum)
               ANSI.hSetCursorColumn IO.stderr 0
-              ANSI.hCursorUp IO.stderr (length lmNamespaces - lineNum)
               ANSI.hClearLine IO.stderr
               let nsText = Text.pack (Namespace.toPath ns)
               let formattedOutput = if Text.null output then "[~] " <> nsText else "[~] " <> nsText <> ": " <> output
               IO.hPutStr IO.stderr (Text.unpack formattedOutput)
               IO.hFlush IO.stderr
-              ANSI.hRestoreCursor IO.stderr
+              -- Move back to bottom
+              ANSI.hCursorDown IO.stderr (numLines - lineNum)
 
 updateLineState :: Namespace -> BuildState -> IO ()
 updateLineState ns buildState = do
@@ -136,9 +135,10 @@ updateLineState ns buildState = do
         case Map.lookup ns nsMap of
           Nothing -> pure ()
           Just lineNum -> do
-            ANSI.hSaveCursor IO.stderr
+            let numLines = length lmNamespaces
+            -- Move to the target line from bottom
+            ANSI.hCursorUp IO.stderr (numLines - lineNum)
             ANSI.hSetCursorColumn IO.stderr 0
-            ANSI.hCursorUp IO.stderr (length lmNamespaces - lineNum)
             ANSI.hClearLine IO.stderr
             let nsText = Text.pack (Namespace.toPath ns)
             case buildState of
@@ -151,4 +151,5 @@ updateLineState ns buildState = do
               Building ->
                 IO.hPutStr IO.stderr (Text.unpack <| "[~] " <> nsText)
             IO.hFlush IO.stderr
-            ANSI.hRestoreCursor IO.stderr
+            -- Move back to bottom
+            ANSI.hCursorDown IO.stderr (numLines - lineNum)