# Continue Feature - Display Fix Summary

## Issue Reported

When hitting a breakpoint, the screen showed **blank** with only the breakpoint header visible. The user couldn't see their code or output.

## Root Cause

The breakpoint callback was calling `curses.initscr()`, which **created a new curses screen**, blanking out the npyscreen interface.

## Fix Applied

Modified `src/ui/curses_ui.py:443-529` to:
1. Use the **existing** npyscreen windows instead of creating new ones
2. Refresh editor and output displays before showing breakpoint status
3. Use `curses.doupdate()` to synchronize screen updates
4. Access input through the existing form window
5. Restore normal display after breakpoint with `form.display()`

### Code Changes

**Before:**
```python
stdscr = curses_module.initscr()  # ❌ Creates new screen
stdscr.addstr(0, 0, status_msg)
stdscr.refresh()
```

**After:**
```python
form.editor.display()              # ✅ Show existing content
form.output.display()
curses.doupdate()                  # ✅ Push to screen
parent_window = form.editor.parent # ✅ Use existing window
parent_window.addstr(0, 0, status_msg)
parent_window.noutrefresh()
curses.doupdate()
```

## Expected Behavior Now

When a breakpoint hits, you should see:
- ✅ **Editor window** - Your BASIC program code
- ✅ **Output window** - Program output generated so far
- ✅ **Status line** - "BREAKPOINT at line XX - Press 'c' continue, 's' step, 'e' end"
- ✅ **NOT** a blank screen!

## Testing

Run the test script:
```bash
./test_continue_fix.sh
```

Or manually:
```bash
python3 mbasic --ui curses test_continue.bas
# Set breakpoint on line 20 (press 'b')
# Press Ctrl+R to run
# Verify you can see the code when breakpoint hits
# Press 'c' to continue
```

## What Changed

| File | Lines | Change |
|------|-------|--------|
| `src/ui/curses_ui.py` | 443-529 | Fixed `_breakpoint_hit()` to use existing npyscreen windows |

## Technical Details

The fix leverages npyscreen's window hierarchy:
- Each widget has a `.parent` curses window
- Calling `.display()` on widgets refreshes their content
- `curses.doupdate()` pushes all pending changes to the physical screen
- Using existing windows preserves all visible content

## Files Created

Documentation:
- `BREAKPOINT_DISPLAY_FIX.md` - Detailed technical explanation
- `CONTINUE_FIX_SUMMARY.md` - This summary
- `test_continue_fix.sh` - Test script for the fix

## Status

✅ **Fix Implemented**
🔄 **Awaiting User Confirmation** - Please test and report if screen is now visible

## If Still Blank

If the screen is still blank after the fix, it may indicate:
1. The `parent_window` reference isn't valid
2. npyscreen's window hierarchy is different than expected
3. Need to use a different method to access the screen

Debug by checking stderr:
```bash
python3 mbasic --ui curses test_continue.bas 2> debug.log
# Run and hit breakpoint
# Check debug.log for errors
```

## Future Enhancements

Once display is confirmed working:
- [ ] Highlight the current line being debugged
- [ ] Show variable values in status line
- [ ] Add a small "variables" window during debug
- [ ] Color-code breakpoint status (green=continue, yellow=step, red=end)

## Related Documentation

- `README_CONTINUE.md` - Continue feature overview
- `DEBUGGER_COMMANDS.md` - All debugger commands
- `CONTINUE_FEATURE.md` - Detailed continue guide
- `BREAKPOINT_SUMMARY.md` - Original breakpoint implementation
