Update app.py

app.py

@@ -19,6 +19,10 @@ import io
 import threading
 import queue
 import time
+import re
+
+# Regex to match ANSI escape codes (like [A, [2K, etc.)
+ANSI_ESCAPE = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')
 
 
 class MigrationTool:
@@ -202,17 +206,57 @@ class MigrationTool:
             new_data = False
             while not log_queue.empty():
                 try:
-                    msg = log_queue.get_nowait()
-                    # Clean up common console control characters for better display
-                    msg = msg.replace('\r', '\n').strip()
-                    if msg:
-                        for line in msg.split('\n'):
-                            clean_line = line.strip()
-                            if clean_line:
+                    raw_msg = log_queue.get_nowait()
+                    # 1. Strip ANSI escape codes (those [A, [m, etc.)
+                    msg = ANSI_ESCAPE.sub('', raw_msg)
+                    if not msg:
+                        continue
+
+                    # 2. Process the message line by line
+                    # We handle \r by treating it as a signal to potentially overwrite the last line
+                    # We handle \n as a signal to start a new line
+                    for line in msg.replace('\r', '\n').split('\n'):
+                        clean_line = line.strip()
+                        if not clean_line:
+                            continue
+
+                        # 3. Smart Progress Bar Handling
+                        # Identify if this line is a progress bar update
+                        # Progress bars usually look like: "Label: 45%|### | ..."
+                        is_progress = '%' in clean_line and '|' in clean_line and ('[' in clean_line or ']' in clean_line)
+                        
+                        if is_progress:
+                            # Extract the label (everything before the progress bar/percentage)
+                            # This helps us identify WHICH progress bar to update
+                            label = clean_line.split('|')[0].split('%')[0].strip()
+                            # If the label ends with a number (like '45'), try to get the text before it
+                            label = re.sub(r'\d+$', '', label).strip()
+                            
+                            found = False
+                            # Look at the last few lines to see if we're updating an existing bar
+                            # We only look back ~10 lines to keep it fast
+                            for i in range(len(output_lines) - 1, max(-1, len(output_lines) - 11), -1):
+                                if label and label in output_lines[i] and ('%' in output_lines[i] or '|' in output_lines[i]):
+                                    output_lines[i] = clean_line
+                                    found = True
+                                    new_data = True
+                                    break
+                            
+                            if not found:
                                 output_lines.append(clean_line)
                                 new_data = True
+                        else:
+                            # Regular log message
+                            output_lines.append(clean_line)
+                            new_data = True
+
                 except queue.Empty:
                     break
+            
+            # Keep the output box from growing infinitely (last 1000 lines)
+            if len(output_lines) > 1000:
+                output_lines[:] = output_lines[-1000:]
+                
             return "\n".join(output_lines), new_data
 
         # Thread-safe migration execution storage