---
phase: 05-live-show-execution
plan: 04
subsystem: ui
tags: [websocket, audio, playback, frontend, javascript]

# Dependency graph
requires:
  - phase: 05-live-show-execution/05-03
    provides: wireKeyboard() with WS play/pause already working for keyboard shortcuts
  - phase: 05-live-show-execution/05-01
    provides: WebSocket cue scheduler with is_playing gate and UDP dispatch
provides:
  - Mouse-initiated play/pause now sends WebSocket messages to server
  - Server is_playing flag correctly set for both mouse and keyboard playback
  - UDP cue scheduler fires for mouse-triggered playback
affects: [05-live-show-execution]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "audio element 'play'/'pause' event listeners send WS messages alongside UI updates — same pattern as wireKeyboard()"

key-files:
  created: []
  modified:
    - lightsync/frontend/app.js

key-decisions:
  - "Audio element event listeners are the correct hook for mouse play/pause — they fire for all triggers (button click, keyboard, programmatic), so WS messages are sent exactly once regardless of source"

patterns-established:
  - "Idempotent WS messages: both wireAudio() and wireKeyboard() send play/pause — harmless because server handlers set a boolean flag"

requirements-completed: [SHW-03, UI-03, UI-04]

# Metrics
duration: 1min
completed: 2026-04-07
---

# Phase 05 Plan 04: Mouse Play/Pause WebSocket Fix Summary

**Audio element event listeners now forward play/pause state to server via WebSocket, enabling UDP cue scheduling for mouse-initiated playback**

## Performance

- **Duration:** ~1 min
- **Started:** 2026-04-07T10:36:50Z
- **Completed:** 2026-04-07T10:37:27Z
- **Tasks:** 1
- **Files modified:** 1

## Accomplishments

- Added `client.send({ type: 'play', position: audio.currentTime })` to the `audio 'play'` event listener in `wireAudio()`
- Added `client.send({ type: 'pause', position: audio.currentTime })` to the `audio 'pause'` event listener in `wireAudio()`
- Server `is_playing` flag now becomes `True` when playback is started via the transport bar mouse button
- UDP cue scheduler (LOOKAHEAD=60ms) now fires animation commands for mouse-initiated shows, not just keyboard Space shortcut

## Task Commits

Each task was committed atomically:

1. **Task 1: Add WebSocket play/pause messages to wireAudio() event listeners** - `ac0f3d5` (feat)

**Plan metadata:** (docs commit follows)

## Files Created/Modified

- `lightsync/frontend/app.js` — Added client.send() calls to 'play' and 'pause' event listeners in wireAudio() (lines 135-136)

## Decisions Made

Audio element event listeners ('play'/'pause') are the correct hook rather than modifying the button click handler. These events fire for ALL triggers — button click, keyboard shortcuts, or programmatic `audio.play()`/`audio.pause()` calls — ensuring the WS message fires exactly once per state change. Both wireAudio() and wireKeyboard() sending the same WS messages is harmless: the server handlers are idempotent (they set `is_playing` to a boolean value).

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered

None.

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness

- Gap closure complete: mouse play/pause now correctly triggers server-side cue scheduling
- All 11 truths from Phase 05 verification should now be satisfied (previously 9/11)
- Phase 05 live-show-execution is fully complete

---
*Phase: 05-live-show-execution*
*Completed: 2026-04-07*