From f26a445fd79af0a775c19baf4646ea46f5ea4f2e Mon Sep 17 00:00:00 2001
From: "Jurgen J. Vinju" <Jurgen.Vinju@cwi.nl>
Date: Wed, 3 Apr 2024 17:26:52 +0200
Subject: [PATCH] this fixes off-by-one issues that are only visible if there
 is extra room atthe bottom of the terminal

---
 .../repl/TerminalProgressBarMonitor.java      | 48 +++++++++++++++++--
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/src/org/rascalmpl/repl/TerminalProgressBarMonitor.java b/src/org/rascalmpl/repl/TerminalProgressBarMonitor.java
index 6c3aeba2475..f88d4703984 100644
--- a/src/org/rascalmpl/repl/TerminalProgressBarMonitor.java
+++ b/src/org/rascalmpl/repl/TerminalProgressBarMonitor.java
@@ -1,6 +1,7 @@
 package org.rascalmpl.repl;
 
 import java.io.FilterOutputStream;
+import java.io.FilterWriter;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.PrintWriter;
@@ -49,13 +50,53 @@ public class TerminalProgressBarMonitor extends FilterOutputStream implements IR
      */
     private final String encoding;
 
+    /**
+     * Will make everything slow, but easier to spot mistakes
+     */
+    private final boolean debug = false;
+
+    @SuppressWarnings("resource")
     public TerminalProgressBarMonitor(OutputStream out, Terminal tm) {
         super(out);
         this.encoding = tm.getOutputEncoding() != null ? tm.getOutputEncoding() : "UTF8";
-        this.writer = new PrintWriter(out, true, Charset.forName(encoding));
+        PrintWriter theWriter = new PrintWriter(out, true, Charset.forName(encoding));
+        this.writer = debug ? new PrintWriter(new AlwaysFlushAlwaysShowCursor(theWriter)) : theWriter;
         this.lineWidth = tm.getWidth();
     }
 
+    /**
+     * Use this for debugging terminal cursor movements, step by step.
+     */
+    private static class AlwaysFlushAlwaysShowCursor extends FilterWriter {
+
+        public AlwaysFlushAlwaysShowCursor(PrintWriter out) {
+            super(out);
+        }
+
+        @Override
+        public void write(int c) throws IOException {
+            out.write(c);
+            out.write(ANSI.showCursor());
+            out.flush();
+        }
+
+        @Override
+        public void write(char[] cbuf, int off, int len) throws IOException {
+            out.write(cbuf, off, len);
+            out.write(ANSI.showCursor());
+            out.flush();
+        }
+
+        @Override
+        public void write(String str, int off, int len) throws IOException {
+            out.write(str, off, len);
+            out.write(ANSI.showCursor());
+            out.flush();
+        }
+
+       
+    }
+
     /**
      * Represents one currently running progress bar
      */
@@ -102,7 +143,7 @@ void update() {
                 writer.write(ANSI.hideCursor());
                 writer.write(ANSI.moveUp(bars.size() - bars.indexOf(this)));
                 write();
-                writer.write(ANSI.moveDown(bars.size() - bars.indexOf(this)));
+                writer.write(ANSI.moveDown(bars.size() - bars.indexOf(this) - 1 /* already wrote a \n */));
                 writer.write(ANSI.showCursor());
                 writer.flush();
             }
@@ -203,7 +244,8 @@ public void done() {
      */
     private void eraseBars() {
         if (bars.isEmpty()) {
-            writer.println();
+            // writer.println();
+            return;
         }
             
         writer.write(ANSI.hideCursor());