---
phase: 04-jamtrack-research-design
plan: 01
subsystem: documentation
tags: [jamtrack, legacy-analysis, react-patterns, api-documentation]

# Dependency graph
requires:
  - phase: 03-backing-track-finalization
    provides: Established React patterns (error handling, performance, jamClient integration)
provides:
  - JAMTRACK_LEGACY.md - Legacy jQuery/CoffeeScript implementation patterns
  - JAMTRACK_API.md - Complete jamClient API reference for JamTrack methods
  - JAMTRACK_REACT_PATTERNS.md - React integration patterns and gap analysis
affects: [05-jamtrack-implementation]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Legacy pattern documentation (jQuery dialogs, CoffeeScript state machines, Reflux stores)"
    - "jamClient JamTrack API surface mapped (15+ methods)"
    - "React component architecture analyzed (existing + gaps)"
    - "Redux state structure documented (mediaSlice, activeSessionSlice, sessionUISlice)"

key-files:
  created:
    - .planning/codebase/JAMTRACK_LEGACY.md
    - .planning/codebase/JAMTRACK_API.md
    - .planning/codebase/JAMTRACK_REACT_PATTERNS.md
  modified: []

key-decisions:
  - "Documented 8-state sync machine (no_client, synchronized, packaging, downloading, keying, initial, quiet, errored)"
  - "Identified fqId format requirement: {jamTrackId}-{sampleRate} for all jamClient calls"
  - "Mapped existing JKSessionJamTrackModal (ready to use) vs missing JKSessionJamTrackPlayer (to be created)"
  - "Identified loadJamTrack thunk bug: uses jamTrack.id instead of fqId format"

patterns-established:
  - "Documentation-driven design: comprehensive reference before implementation"
  - "Legacy-to-React migration pattern: document → design → implement"
  - "Gap analysis methodology: existing components vs required functionality"

issues-created: []

# Metrics
duration: 21min
completed: 2026-01-14
---

# Phase 4 Plan 1: Document Legacy JamTrack Implementation Summary

**Comprehensive documentation of legacy JamTrack patterns, jamClient API, and React integration strategy for Phase 5 implementation**

## Performance

- **Duration:** 21 min
- **Started:** 2026-01-14T15:47:24Z
- **Completed:** 2026-01-14T16:08:29Z
- **Tasks:** 3
- **Files created:** 3

## Accomplishments

- **JAMTRACK_LEGACY.md** (264 lines): Captured 8-state download/sync machine, jQuery dialog patterns, Reflux stores, WebSocket subscriptions, REST API endpoints, and integration points
- **JAMTRACK_API.md** (569 lines): Documented all 15+ JamTrack jamClient methods with signatures, parameters, return types, usage examples, and comparison to Backing Track APIs
- **JAMTRACK_REACT_PATTERNS.md** (557 lines): Mapped existing React components, Redux state structure, hook patterns, data flow, and identified 20+ gaps for Phase 5

## Task Commits

Each task was committed atomically:

1. **Task 1: Create JAMTRACK_LEGACY.md** - `b7208d945` (docs)
2. **Task 2: Create JAMTRACK_API.md** - `d3ff1f147` (docs)
3. **Task 3: Create JAMTRACK_REACT_PATTERNS.md** - `d402b22fc` (docs)

**Plan metadata:** (pending - this commit)

## Files Created/Modified

**Created:**
- `.planning/codebase/JAMTRACK_LEGACY.md` - Legacy implementation reference (jQuery, CoffeeScript, Reflux)
- `.planning/codebase/JAMTRACK_API.md` - jamClient JamTrack API documentation
- `.planning/codebase/JAMTRACK_REACT_PATTERNS.md` - React patterns and Phase 5 gap analysis

**Modified:** None

## Decisions Made

**Legacy Pattern Insights:**
- **8-state synchronization machine**: Documented state transitions (no_client → initial → packaging → downloading → keying → synchronized)
- **fqId format is mandatory**: All jamClient JamTrack calls require `{jamTrackId}-{sampleRate}` format, not just ID
- **Mixdown selection logic**: pickMyPackage() filters by `file_type == 'ogg' && encrypt_type == 'jkz' && sample_rate == @sampleRate`
- **JMEP must load before play**: `JamTrackLoadJmep(fqId, jmepData)` called before `JamTrackPlay(fqId)`
- **Callback pattern**: jamClient download callbacks passed as string names, not function references

**React Architecture Findings:**
- **Existing ready-to-use**: JKSessionJamTrackModal, useMediaActions pattern, Redux infrastructure
- **Missing components**: JKSessionJamTrackPlayer (main work), download/sync widget
- **Redux state gaps**: jamTrackState needs expansion, download/sync tracking missing, loadJamTrack thunk uses wrong ID format
- **Performance patterns**: Apply Phase 3 optimizations (visibility-aware polling, useCallback, lazy updates)

**Critical implementation notes:**
- jamClient returns Promises (always async/await)
- jamClient returns strings for position/duration (always parseInt)
- jamClient passed as prop, never stored in Redux (non-serializable)
- Cleanup on unmount required (prevent stale state)

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered

None - all legacy files accessible, API methods documented, React patterns analyzed successfully.

## Next Phase Readiness

**Phase 4 Plan 2 ready to execute** with complete reference documentation:

**Documentation completeness:**
- ✓ All legacy patterns captured (dialog, state machine, stores, API endpoints, integration)
- ✓ All jamClient methods documented (15+ methods with signatures and examples)
- ✓ React architecture mapped (components, Redux, hooks, data flow)
- ✓ Gap analysis complete (20+ specific items for Phase 5)
- ✓ Code references accurate with line numbers

**Phase 5 implementation path clear:**
1. Fix loadJamTrack thunk fqId format bug
2. Create JKSessionJamTrackPlayer component (similar to Backing Track)
3. Implement download/sync state machine in React
4. Expand Redux state for player and sync tracking
5. Add WebSocket handlers (JAM_TRACK_CHANGES, MIXDOWN_CHANGES)
6. Implement mixdown selection and CRUD operations

**Lessons from documentation process:**
- Legacy CoffeeScript state machine complexity well-documented for React translation
- jamClient API surface larger than Backing Track (15+ vs 8 methods)
- Existing React infrastructure strong foundation (modal, Redux, hooks)
- Phase 3 Backing Track patterns directly applicable with extensions

---
*Phase: 04-jamtrack-research-design*
*Completed: 2026-01-14*
