---
phase: 05-jamtrack-implementation
plan: 04
subsystem: ui
tags: [react, redux, jamtrack, audio-player, mixdown-selection, download-ui]

# Dependency graph
requires:
  - phase: 05-jamtrack-implementation-03
    provides: JamTrack player foundation with playback controls
  - phase: 04-jamtrack-research-design
    provides: Component design and Redux architecture for mixdowns
provides:
  - Mixdown fetching and organization (master/custom/stems hierarchy)
  - Mixdown picker UI with sorted display
  - Download/sync UI with 6-state machine visualization
  - Cancel and retry download functionality
affects: [05-jamtrack-implementation-05, jamtrack-playback, audio-download]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - Mixdown hierarchy organization (master → custom → stems)
    - 6-state download machine UI (idle → checking → downloading → keying → synchronized → error)
    - Atomic per-task commits for feature implementation

key-files:
  created: []
  modified:
    - jam-ui/src/components/client/JKSessionJamTrackPlayer.js

key-decisions:
  - "Fetch mixdowns during player initialization (non-fatal error if fails)"
  - "Default mixdown selection prefers master mix, falls back to first available"
  - "Mixdown change requires stop/restart of playback if currently playing"
  - "Visual indicators for mixdown types: 🎵 master, 🎨 custom, 🎸 stem"
  - "Hide download UI for idle and synchronized states (only show active states)"
  - "Step indicator shown when totalSteps > 0 during download"

patterns-established:
  - "Mixdown organization: master/customMixes/stems hierarchy from API response"
  - "Mixdown picker sorting: master first, then custom mixes, then stems (alphabetical within types)"
  - "Download state machine: 6 distinct states with appropriate UI for each"
  - "Cancel during download: calls JamTrackCancelDownload and resets state to idle"
  - "Retry on error: clears error state and re-triggers loadJamTrack thunk"

issues-created: []

# Metrics
duration: 18min
completed: 2026-01-15
---

# Phase 05-04: JamTrack Mixdown Selection and Download UI

**JamTrack player with mixdown picker (master/custom/stems hierarchy), download progress tracking (0-100%), and 6-state sync machine UI (checking/downloading/keying/error) with cancel/retry functionality**

## Performance

- **Duration:** 18 min
- **Started:** 2026-01-15T19:27:48Z
- **Completed:** 2026-01-15T19:45:52Z
- **Tasks:** 3
- **Files modified:** 1

## Accomplishments
- Mixdown fetching and organization during player initialization with master/customMixes/stems hierarchy
- Mixdown picker dropdown with visual indicators and hierarchical sorting
- Complete 6-state download/sync UI showing progress bar, step indicators, and state-specific actions
- Cancel and retry functionality for download operations
- Integration with Redux state (availableMixdowns, activeMixdown, downloadState)

## Task Commits

Each task was committed atomically:

1. **Task 1: Fetch and organize mixdowns** - `701410715` (feat)
2. **Task 2: Implement mixdown picker UI** - `845b44a31` (feat)
3. **Task 3: Implement download/sync UI** - `6a68d8b40` (feat)

## Files Created/Modified
- `jam-ui/src/components/client/JKSessionJamTrackPlayer.js` - Added mixdown fetching, picker UI, and download state machine visualization

## Decisions Made
- **Mixdown fetching timing:** Fetch during initialization after sync check, before autoPlay load. Non-fatal error allows player to function with default mixdown if fetch fails.
- **Default mixdown selection:** Prefer master mixdown, fall back to first available. Ensures predictable behavior for users.
- **Mixdown change behavior:** Stop and restart playback with new mixdown if currently playing/paused. Provides immediate feedback of mixdown switch.
- **Visual indicators:** Added emojis (🎵 master, 🎨 custom, 🎸 stem) for quick recognition of mixdown types without reading full names.
- **Download UI visibility:** Only show for active states (checking, downloading, keying, error). Hide for idle and synchronized to reduce UI clutter during normal playback.
- **Step indicator:** Conditionally render "Step X of Y" only when totalSteps > 0. Handles cases where native client may not provide step information.

## Deviations from Plan

None - plan executed exactly as written. All three tasks implemented following the specified patterns:
- Task 1: Mixdown fetching with JamTrackGetMixdowns, hierarchy organization, Redux storage
- Task 2: handleMixdownChange callback, sorted dropdown with visual indicators
- Task 3: handleCancelDownload and handleRetryDownload callbacks, 6-state UI with progress bar

## Issues Encountered
None - implementation proceeded smoothly following the detailed task specifications.

## Next Phase Readiness
- Mixdown selection and download UI complete
- Ready for Phase 05-05: Loop control implementation
- Player can now display and switch between different mixdowns (master/custom/stems)
- Download progress visualization provides clear feedback during JamTrack sync operations
- Cancel/retry functionality handles edge cases in download flow

---
*Phase: 05-jamtrack-implementation*
*Completed: 2026-01-15*
