# Variable Window Sorting Refactoring - COMPLETED

## Summary

Successfully refactored variable sorting across all three UI backends (Web, Tk, Curses) to use a common helper module. All UIs now have consistent sorting behavior and Tk-style controls.

## Completed Work

### 1. ✅ Created Common Variable Sorting Helper

**File**: `src/ui/variable_sorting.py`

**Functions implemented:**
- `get_variable_sort_modes()` - List of available sort modes with metadata
- `cycle_sort_mode(current_mode)` - Cycle through sort modes
- `get_sort_key_function(sort_mode)` - Get sort key function for a mode
- `sort_variables(variables, sort_mode, reverse)` - Main sorting function
- `get_sort_mode_label(sort_mode)` - Get display label for mode
- `get_default_reverse_for_mode(sort_mode)` - Get default direction

**Sort modes supported:**
- `accessed` - Last accessed (max of read OR write timestamp) - DEFAULT
- `written` - Last write timestamp
- `read` - Last read timestamp
- `name` - Variable name (case-insensitive alphabetical)
- `type` - Type suffix ($, %, !, #)
- `value` - Smart sorting (arrays last, then numeric/string)

### 2. ✅ Implemented Tk-Style Variable Column Header (Web UI)

**Location**: `src/ui/web/nicegui_backend.py` - VariablesDialog class

**Features:**
- Two-button control system:
  - **Arrow button (↓/↑)**: Toggle sort direction
  - **Mode label button**: Cycle through sort modes
- Display shows current mode: "Variable (Last Accessed)"
- Both buttons trigger dialog close/reopen to refresh display
- Maintains sort state between opens

**Methods added:**
- `_toggle_direction()` - Toggle sort direction and refresh
- `_cycle_mode()` - Cycle to next mode and refresh

### 3. ✅ Refactored Web UI to Use Common Helper

**File**: `src/ui/web/nicegui_backend.py`

**Changes:**
- Imported helper functions: `sort_variables`, `get_sort_mode_label`, `cycle_sort_mode`
- Added sort state to VariablesDialog: `self.sort_mode`, `self.sort_reverse`
- Replaced inline sorting logic with `sort_variables()` call
- Used `get_sort_mode_label()` for display text
- Used `cycle_sort_mode()` for mode cycling

### 4. ✅ Refactored Tk UI to Use Common Helper

**File**: `src/ui/tk_ui.py`

**Changes:**
- Added import: `from src.ui.variable_sorting import ...`
- Simplified `_cycle_variable_sort()` to use `cycle_sort_mode()`
- Updated `_update_variable_headings()` to use `get_sort_mode_label()`
- Replaced 30+ lines of sort key logic in `_update_variables()` with single call to `sort_variables()`

### 5. ✅ Refactored Curses UI to Use Common Helper

**File**: `src/ui/curses_ui.py`

**Changes:**
- Added import: `from src.ui.variable_sorting import ...`
- Replaced inline sort key logic in `_update_variables_window()` with `sort_variables()` call
- Updated `_cycle_variables_sort_mode()` to use `get_sort_mode_label()`
- Updated window title generation to use `get_sort_mode_label()`

**Note**: Curses UI keeps all 6 modes in cycle (name, accessed, written, read, type, value) since it doesn't have separate column headers.

## Benefits Achieved

1. **Consistency**: All three UIs now sort variables identically
2. **Maintainability**: Sorting logic in one place - bug fixes apply everywhere
3. **Code Reduction**: Removed ~90 lines of duplicate code across UIs
4. **Feature Parity**: Web UI now has Tk-style sorting controls
5. **Testing**: Can unit test sorting independently of UI code
6. **Extensibility**: Easy to add new sort modes in the future

## Technical Details

### Sort Algorithm

All timestamp-based sorts (accessed, written, read) default to `reverse=True` (newest first).
All value-based sorts (name, type, value) default to `reverse=False` (ascending).

### Value Sorting Logic

Complex three-tier sorting for value mode:
1. Arrays sort last: `(1, '', 0)`
2. Strings sort alphabetically: `(0, str.lower(), 0)`
3. Numbers sort numerically: `(0, '', float_value)`

### Accessed Timestamp Calculation

"Accessed" means most recent of either read OR write:
```python
max(v['last_read']['timestamp'], v['last_write']['timestamp'])
```

## Testing Recommendations

1. Test all sort modes in all three UIs
2. Verify default sort (accessed, descending) works correctly
3. Test toggle direction in all UIs
4. Test cycle mode in all UIs
5. Verify filter works with all sort modes
6. Test with arrays, strings, and numeric variables

## Files Changed

1. `src/ui/variable_sorting.py` - NEW FILE (common helper)
2. `src/ui/web/nicegui_backend.py` - VariablesDialog refactored
3. `src/ui/tk_ui.py` - Sorting logic refactored
4. `src/ui/curses_ui.py` - Sorting logic refactored

## Completion Date

2025-10-31
