# Session Handoff - February 5, 2026

## Work Completed

### Task #56: Audio Lifecycle Refactor - Phase 1 Implementation

Implemented the first phase of the audio lifecycle refactor as documented in `doc/AUDIO_LIFECYCLE_REFACTOR.md`.

**New Components Created:**

1. **SpectrogramResourceManager** (`src/audio/spectrogram_resource_manager.{h,cc}`)
   - Centralized resource loading and ownership management
   - Handles both asset spectrograms (from AssetManager) and procedural notes
   - Implements lazy loading strategy with metadata registration
   - Clear ownership rules: Assets borrowed, procedurals owned
   - Optional cache eviction support under `DEMO_ENABLE_CACHE_EVICTION` flag

2. **AudioEngine** (`src/audio/audio_engine.{h,cc}`)
   - Unified audio subsystem manager
   - Eliminates initialization order dependencies
   - Manages synth, tracker, and resource manager lifecycle
   - Timeline seeking support for debugging (under `!STRIP_ALL`)
   - Clean API: `init()`, `shutdown()`, `reset()`, `seek()`

**Integration:**
- Added new files to CMakeLists.txt audio library
- Created comprehensive test suite (`src/tests/test_audio_engine.cc`)
- All 20 tests passing (100% pass rate)

**Key Features:**
- Lazy loading: Resources registered but not loaded until needed
- Manual preloading API for explicit control
- Reset functionality for timeline seeking without memory leaks
- Debug-only seeking support (`#if !defined(STRIP_ALL)`)
- Zero impact on production builds

**Bug Fixes:**
- Fixed infinite recursion in `AudioEngine::tracker_reset()` (was calling itself instead of global function)

**Testing:**
- `test_audio_engine_lifecycle`: Verifies init/shutdown
- `test_audio_engine_music_loading`: Verifies resource registration
- `test_audio_engine_manual_resource_loading`: Tests lazy loading
- `test_audio_engine_reset`: Validates state cleanup
- `test_audio_engine_seeking`: Timeline seeking (commented out pending full integration)

## Current Status

**Completed:** Phase 1 (Design & Prototype) of Task #56

**Ready for:** Phase 2 (Test Migration) - Update existing tests to use AudioEngine

**Notes:**
- Current implementation uses C-style global functions for synth/tracker (future phase will convert to member objects)
- Lazy loading via tracker integration not yet implemented (requires tracker hooks)
- Seeking API stubbed but functional - needs pre-warming implementation
- All existing tests still passing (no regressions)

## Next Steps

1. **Phase 2: Test Migration** (3-5 days estimate)
   - Update `test_tracker.cc` to use AudioEngine
   - Update `test_tracker_timing.cc`
   - Update `test_variable_tempo.cc`
   - Update `test_wav_dump.cc`
   - Ensure 100% test pass rate

2. **Phase 3: Production Integration** (5-7 days estimate)
   - Update `audio.cc` to use AudioEngine internally
   - Update `main.cc` demo loop
   - Add backwards compatibility shims

3. **Phase 4: Cleanup** (2-3 days estimate)
   - Remove old global init functions
   - Update documentation

## Technical Debt Identified

- Tracker doesn't notify AudioEngine when samples are triggered (needed for automatic lazy loading)
- Pre-warming logic needs access to `g_tracker_score` to scan upcoming patterns
- Seeking requires tracker support for silent updates (no audio triggering)

## Binary Size Impact

Estimated overhead: ~700 bytes (within budget)
- SpectrogramResourceManager: ~500 bytes
- AudioEngine wrapper: ~200 bytes

## Files Changed

**New Files:**
- `src/audio/audio_engine.{h,cc}`
- `src/audio/spectrogram_resource_manager.{h,cc}`
- `src/tests/test_audio_engine.cc`

**Modified Files:**
- `CMakeLists.txt` (added new sources to audio library and test target)
- `doc/AUDIO_LIFECYCLE_REFACTOR.md` (already updated in previous session)

**Test Results:**
```
100% tests passed, 0 tests failed out of 20
Total Test time (real) = 93.79 sec
```