# Phase 4: Cleanup & Polish - Make It Sexy

## Critical Issues to Fix

### 1. Debug Console UI Jank

**Problem**: Page content shifts RIGHT when debug console opens (counter-intuitive)
- Expected: Content shifts LEFT to make room
- Current: Content margin-right increases, pushing content right

**Fix**:
```css
/* BEFORE (wrong) */
body.debug-open #app {
    margin-right: 420px;  /* Pushes content right - bad! */
}

/* AFTER (correct) */
body.debug-open #app {
    margin-right: 0;      /* Keep in place or... */
    /* OR shift left to center remaining space */
    transform: translateX(-200px);
}
```

### 2. Un-Ritzy Toggle Implementation (CRITICAL)

**Current (WRONG)**: JS manipulates DOM classes, WASM calls JS bridge function
```python
# ANTI-PATTERN - calling JS to manipulate DOM!
@external
def js_toggle_debug_console():
    pass

def toggle():
    js_toggle_debug_console()  # ❌ JS does the work
```

**Correct (RITZY)**: Signal drives reactive class, declarative event binding
```python
# THE RITZ WAY - declarative and reactive!
console_open = signal(False)

@event('keydown')  # Declarative event registration
def handle_keydown(event):
    if event.key == '`' and event.ctrlKey:
        console_open.value = not console_open.value

def toggle():
    """Button click handler"""
    console_open.value = not console_open.value

# Reactive class binding (syntax TBD)
with Div(class_=lambda: 'ritz-debug' if console_open else 'ritz-debug hidden'):
    # ...or maybe:
    # class_={'ritz-debug': True, 'hidden': not console_open}
```

**What this requires**:

#### A. Reactive Class Binding
- [ ] Parser support for lambda/function in class attribute
- [ ] Codegen to track class dependencies on signals
- [ ] Runtime bridge: `js_set_class(elem_id, class_string)`
- [ ] Signal updates trigger class re-evaluation

#### B. Declarative Event System (`@event` decorator)
- [ ] `@event('keydown')` decorator in syntax.py
- [ ] Parser recognizes @event and extracts event type
- [ ] Codegen emits global event registration (not element-specific)
- [ ] Runtime: `js_register_global_event(event_type, handler_name)`
- [ ] JS passes event object to WASM with properties
- [ ] WASM can access `event.key`, `event.ctrlKey`, etc.

#### C. Event Object Bridge
- [ ] Define event object structure (dict/struct in WASM)
- [ ] JS serializes event properties to WASM memory
- [ ] WASM handler receives event pointer
- [ ] Helper functions: `event_get_key()`, `event_get_ctrl_key()`, etc.

## Framework Improvements Needed

### 3. Reactive Attribute System (Beyond Classes)

Make ALL attributes reactive:
```python
disabled = signal(False)
with Button(disabled=disabled):
    yield "Click me"

# When disabled changes, button.disabled updates automatically
```

**Implementation**:
- [ ] Track attribute dependencies on signals
- [ ] Generate update functions for each reactive attribute
- [ ] Runtime bridge: `js_set_attribute_bool()`, `js_set_attribute_int()`, etc.

### 4. Testing Infrastructure

**Problem**: No way to test Ritz code without manual browser testing

**Solution A: Python Interpreter Mode**
```bash
# Run Ritz components in pure Python for testing
python3 -m ritz.test examples/highfive/HighFive.py

# Output:
# ✓ HighFive renders correctly
# ✓ increment() updates signal
# ✓ Button has correct onclick handler
```

Implementation:
- [ ] Create `ritz/test_runtime.py` - Python VNode interpreter
- [ ] Execute component functions, track signal changes
- [ ] Assert on rendered VNode tree structure
- [ ] Mock event handlers and verify signal updates

**Solution B: LLVM Interpreter**
```bash
# Execute LLVM IR directly (no WASM step)
python3 -m ritz.test --llvm examples/highfive/HighFive.py

# Uses: lli (LLVM interpreter) or llvm-python bindings
```

Implementation:
- [ ] Mock JS bridge functions in C/LLVM
- [ ] Execute LLVM IR with test assertions
- [ ] Verify correct function calls and signal state

**Solution C: Headless Browser Tests**
```bash
# Full integration tests with Playwright/Puppeteer
python3 -m ritz.test --browser examples/highfive/HighFive.py
```

Implementation:
- [ ] Playwright/Puppeteer test harness
- [ ] Load WASM in headless browser
- [ ] Verify DOM structure and interactions
- [ ] Snapshot testing for visual regression

### 5. Test Coverage Requirements

**Unit Tests Needed**:
- [ ] Parser: All AST node types
- [ ] Parser: @component, @external, @event decorators
- [ ] Codegen: Signal generation
- [ ] Codegen: Event handler generation
- [ ] Codegen: Reactive attributes
- [ ] Codegen: Conditional rendering
- [ ] Runtime: Signal updates
- [ ] Runtime: Event dispatch
- [ ] Runtime: DOM mutations

**Integration Tests Needed**:
- [ ] Counter component (signals + events)
- [ ] Tabs component (match/case conditionals)
- [ ] Forms (input binding, validation)
- [ ] Debug console (global events, reactive classes)

**Snapshot Tests**:
- [ ] Generated LLVM IR (detect codegen regressions)
- [ ] Generated WASM size (detect bloat)
- [ ] Rendered HTML structure

## Code Quality & Consistency

### 6. Example App Consistency

Update all examples to use:
- [ ] RitzMain() convention
- [ ] Main.wasm output
- [ ] template.html (no custom HTML)
- [ ] Shared styles.css
- [ ] Component-specific styles in <style> tag only
- [ ] @external for any JS bridge functions
- [ ] Consistent naming conventions

Examples to update:
- [ ] `examples/tabs/Tabs.py` - Add RitzMain
- [ ] `examples/textinput/TextInput.py` - Add RitzMain
- [ ] `examples/toggle/Toggle.py` - Add RitzMain
- [ ] All: Copy template.html
- [ ] All: Remove duplicate styles

### 7. Documentation

- [ ] Update CLAUDE.md with @external decorator
- [ ] Update CLAUDE.md with @event decorator (when implemented)
- [ ] Document reactive attribute syntax
- [ ] Testing guide (how to run tests)
- [ ] Examples README with descriptions

## Architecture Questions to Resolve

### 8. Reactive Class Syntax

**Option 1: Lambda (Python-like)**
```python
with Div(class_=lambda: 'active' if is_active else 'inactive'):
```
Pros: Pythonic, clear dependency
Cons: Lambdas need special handling in parser

**Option 2: Template strings (f-string-like)**
```python
with Div(class_=f"menu {('active' if is_open else '')}"):
```
Pros: Familiar syntax
Cons: Hard to track dependencies, less clear

**Option 3: Dict with signal values**
```python
with Div(class_={'menu': True, 'active': is_open, 'disabled': is_disabled}):
```
Pros: Very clear dependencies, React-like
Cons: Different from HTML class syntax

**Decision needed**: Which syntax to use?

### 9. Event Object Design

How should event handlers access event properties?

**Option 1: Parameter object (dict-like)**
```python
@event('keydown')
def handle_keydown(event):
    if event['key'] == '`' and event['ctrlKey']:
        ...
```

**Option 2: External functions**
```python
@external
def event_get_key() -> str:
    pass

@event('keydown')
def handle_keydown():
    if event_get_key() == '`' and event_get_ctrl_key():
        ...
```

**Option 3: Global event context**
```python
@event('keydown')
def handle_keydown():
    if current_event.key == '`' and current_event.ctrlKey:
        ...
```

**Decision needed**: Which approach?

## Success Criteria

Before moving to Phase 5 (was Phase 4), we must have:

- ✅ Debug console opens/closes with proper CSS transitions
- ✅ Page content shifts LEFT (or stays in place) when console opens
- ✅ Console toggle is 100% Ritz (signal + reactive class)
- ✅ Ctrl+` registered declaratively with @event decorator
- ✅ Event object accessible in WASM handlers
- ✅ Test infrastructure in place (at least Python mode)
- ✅ All examples updated to use RitzMain convention
- ✅ Test coverage >70% for parser and codegen
- ✅ Documentation updated
- ✅ No JS DOM manipulation (except initial setup)

## Timeline Estimate

- **Reactive classes**: 2-3 hours (parser + codegen + runtime)
- **@event decorator**: 3-4 hours (parser + codegen + runtime + event bridge)
- **Event object bridge**: 2-3 hours (memory layout + JS serialization)
- **Python test mode**: 4-5 hours (VNode interpreter + test harness)
- **Unit tests**: 3-4 hours (parser, codegen tests)
- **Example cleanup**: 1-2 hours (update 4 examples)
- **Debug console refactor**: 1-2 hours (use reactive classes + @event)

**Total**: ~20-25 hours of focused work

## Notes

- The @external decorator is **beautiful** and should be the template
- Everything should feel declarative and Pythonic
- WASM should handle logic, JS should only bridge
- Tests are critical - no more manual browser testing for every change
- Keep examples simple and pedagogical