# Task Completion Summary

All 5 tasks have been successfully completed:

## ✅ Task #1: Fix real-time audio peak measurement for visual sync
**Issue:** Visual effects triggered 400ms before audio was heard due to peak measurement at ring buffer write time.

**Solution:**
- Added `get_realtime_peak()` to AudioBackend interface
- Implemented real-time peak measurement in audio callback
- Updated main.cc and test_demo.cc to use `audio_get_realtime_peak()`
- Fixed peak decay rate from 0.95 (6 second fade) to 0.7 (1 second fade)

**Files Modified:**
- src/audio/audio_backend.h
- src/audio/backend/miniaudio_backend.{h,cc}
- src/audio/backend/{mock,wav_dump,jittered,silent}_backend.{h,cc}
- src/audio/audio.{h,cc}
- src/main.cc
- src/test_demo.cc
- src/tests/test_audio_backend.cc

**Result:** Audio-visual synchronization now accurate, visual effects fade smoothly.

---

## ✅ Task #2: Create SilentBackend for audio testing
**Goal:** Test audio.cc functionality without hardware.

**Implementation:**
- Created SilentBackend class implementing AudioBackend interface
- No audio output (silent), pure inspection/testing
- Controllable peak for testing edge cases
- Tracks frames rendered and voice triggers

**Files Created:**
- src/audio/backend/silent_backend.{h,cc}
- src/tests/test_silent_backend.cc

**Tests Added:** 7 comprehensive tests covering:
- Lifecycle (init/start/shutdown)
- Peak control
- Frame/voice tracking
- Playback time
- Buffer management
- audio_update()

**Result:** 28/28 tests pass, improved audio.cc test coverage.

---

## ✅ Task #3: Reorganize audio backends to audio/backend/ directory
**Goal:** Improve codebase organization.

**Changes:**
- Created src/audio/backend/ directory
- Moved all backend implementations:
  - miniaudio_backend.{h,cc}
  - mock_audio_backend.{h,cc}
  - wav_dump_backend.{h,cc}
  - jittered_audio_backend.{h,cc}
  - silent_backend.{h,cc}
- Kept audio_backend.h in src/audio/ (interface)
- Updated all #include paths
- Updated CMakeLists.txt paths

**Files Modified:**
- CMakeLists.txt (AUDIO_SOURCES and test targets)
- src/audio/audio.cc
- src/main.cc
- src/tests/*.cc (all backend-using tests)
- All backend .{h,cc} files (relative includes)

**Result:** Cleaner directory structure, all 28 tests pass.

---

## ✅ Task #4: Remove dead code (register_spec_asset)
**Goal:** Remove unused function.

**Analysis:** Function was never called anywhere in codebase.

**Changes:**
- Removed declaration from src/audio/audio.h
- Removed implementation from src/audio/audio.cc

**Result:** Code cleanup complete, all 28 tests pass.

---

## ✅ Task #5: Add comprehensive tests for audio.cc coverage
**Status:** Completed via Task #2 (SilentBackend tests).

**Coverage Improvements:**
- audio_init/start/shutdown: ✓ tested
- audio_get_realtime_peak: ✓ tested
- audio_render_ahead: ✓ tested
- audio_update: ✓ tested
- audio_get_playback_time: ✓ tested
- Buffer management: ✓ tested

**Result:** Significant audio.cc coverage improvement.

---

## Final Status

**Tests:** 28/28 passing (100%)
**Build:** Clean, no warnings
**Executables:** demo64k and test_demo build successfully
**Code Quality:** Improved organization, dead code removed, comprehensive tests

**Notable Improvements:**
1. Audio-visual sync fixed (400ms timing issue resolved)
2. Peak decay optimized (6s → 1s fade time)
3. Test infrastructure enhanced (SilentBackend)
4. Code organization improved (backend/ subdirectory)
5. Test coverage significantly improved

**Ready for:** Further development or testing