docs(07-02): complete async thunks and api integration plan

Phase 7 Plan 2 Summary:
- Implemented getChatMessages and sendChatMessage REST API methods
- Created fetchChatHistory async thunk with message deduplication
- Created sendMessage async thunk with optimistic UI updates
- Extracted createOptimisticMessage helper function
- 67 total tests passing (14 REST API, 53 Redux slice)
- 100% test coverage for all async operations
- Followed strict TDD methodology (RED-GREEN-REFACTOR)
- 7 commits: 3 RED phases, 3 GREEN phases, 1 REFACTOR phase

Updated metadata:
- STATE.md: Phase 7 progress 2/3 plans, 40% v1.1 milestone
- ROADMAP.md: Marked 07-02 complete
- Created 07-02-SUMMARY.md with complete accomplishments

Ready for Plan 07-03 (WebSocket Integration & Selectors).

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -130,7 +130,7 @@ Plans:
 
 Plans:
 - [x] 07-01: Redux Slice & Core Reducers (TDD) - sessionChatSlice with 7 reducers, message deduplication, unread tracking
-- [ ] 07-02: Async Thunks & API Integration (TDD) - REST methods, fetchChatHistory, sendMessage with optimistic updates
+- [x] 07-02: Async Thunks & API Integration (TDD) - REST methods, fetchChatHistory, sendMessage with optimistic updates
 - [ ] 07-03: WebSocket Integration & Selectors (TDD) - CHAT_MESSAGE handler, 8 memoized selectors, localStorage persistence
 
 #### Phase 8: Chat Window UI & Message Display
@@ -182,7 +182,7 @@ Phases execute in numeric order: 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 →
 | 4. JamTrack Research & Design | v1.0 | 2/2 | Complete | 2026-01-14 |
 | 5. JamTrack Implementation | v1.0 | 5/5 | Complete | 2026-01-14 |
 | 6. Session Chat Research & Design | v1.1 | 2/2 | Complete | 2026-01-26 |
-| 7. Chat Infrastructure & State Management | v1.1 | 1/3 | In progress | 2026-01-27 |
+| 7. Chat Infrastructure & State Management | v1.1 | 2/3 | In progress | 2026-01-27 |
 | 8. Chat Window UI & Message Display | v1.1 | 0/TBD | Not started | - |
 | 9. Message Composition & Sending | v1.1 | 0/TBD | Not started | - |
 | 10. Read/Unread Status Management | v1.1 | 0/TBD | Not started | - |

.planning/STATE.md

@@ -9,12 +9,12 @@ See: .planning/PROJECT.md (updated 2026-01-13)
 
 ## Current Position
 
-Phase: 6 of 11 (Session Chat Research & Design)
-Plan: 06-02 Complete
-Status: Phase 6 complete, ready for Phase 7 (Chat Infrastructure & State Management)
-Last activity: 2026-01-26 — Plan 2 (React Architecture Design) complete
+Phase: 7 of 11 (Chat Infrastructure & State Management)
+Plan: 07-02 Complete
+Status: Phase 7 in progress (2/3 plans complete), ready for Plan 07-03 (WebSocket Integration)
+Last activity: 2026-01-27 — Plan 2 (Async Thunks & API Integration) complete
 
-Progress: ███░░░░░░░ 33% (v1.1)
+Progress: ████░░░░░░ 40% (v1.1)
 
 ## Performance Metrics
 
@@ -35,9 +35,9 @@ Progress: ███░░░░░░░ 33% (v1.1)
 | 5 | 5 | 54 min | 10.8 min |
 
 **v1.1 Music Session Chat (In Progress):**
-- Total plans completed: 2
+- Total plans completed: 4 (Phase 6: 2 plans, Phase 7: 2 plans)
 - Total phases: 6 (phases 6-11)
-- Progress: 33% (Phase 6 complete - 2 plans)
+- Progress: 40% (Phase 6 complete, Phase 7 in progress - 2/3 plans)
 
 **Recent Trend:**
 - Last milestone: v1.0 completed 2026-01-14 with excellent velocity
@@ -180,6 +180,29 @@ Recent decisions affecting current work:
 - Deferred features: Server-side read/unread tracking, file attachments, message search/filtering, editing/deletion, typing indicators, emoji picker, multi-channel tabs, notification sounds, desktop notifications
 - 3 design documents created: CHAT_COMPONENT_DESIGN.md (954 lines), CHAT_REDUX_DESIGN.md (1132 lines), IMPLEMENTATION_ROADMAP.md (1138 lines)
 
+**From Phase 7 Plan 1 (07-chat-infrastructure):**
+- Created sessionChatSlice.js with complete initial state structure matching CHAT_REDUX_DESIGN.md
+- Implemented 7 reducers using strict TDD: addMessageFromWebSocket, setActiveChannel, openChatWindow, closeChatWindow, markAsRead, incrementUnreadCount, setWindowPosition
+- Comprehensive unit test suite with 40 tests and 100% reducer coverage
+- Message deduplication logic validated (critical for WebSocket + REST scenario)
+- Unread tracking system tested across multi-channel scenarios
+- Channel key construction: session uses sessionId directly, lesson uses lessonSessionId, global uses 'global'
+- Registered sessionChat slice in Redux store configuration
+- Commit history: 6 commits following TDD RED-GREEN phases
+
+**From Phase 7 Plan 2 (07-chat-infrastructure):**
+- REST API methods: getChatMessages (fetch with pagination), sendChatMessage (send to channel)
+- Native fetch API used instead of apiFetch wrapper for explicit control over credentials/headers
+- fetchChatHistory async thunk: pending/fulfilled/rejected lifecycle with message deduplication and sorting
+- sendMessage async thunk: optimistic UI updates with pending (add temp message), fulfilled (replace), rejected (remove)
+- createOptimisticMessage helper extracted for code clarity
+- Message deduplication prevents duplicates from WebSocket + REST scenario
+- Chronological sorting (createdAt ASC) maintains proper message order
+- Pagination cursor storage in nextCursors state for infinite scroll
+- 67 total tests passing: 14 REST API tests, 53 Redux slice tests
+- Test coverage: 100% for all async operations and state transitions
+- Commit history: 7 commits following TDD RED-GREEN-REFACTOR phases
+
 ### Deferred Issues
 
 **From Phase 3 Plan 3 UAT:**
@@ -210,8 +233,8 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-01-26
-Stopped at: Phase 6 Plan 2 complete (React Architecture Design)
+Last session: 2026-01-27
+Stopped at: Phase 7 Plan 2 complete (Async Thunks & API Integration)
 Resume file: None
 
-**Next:** Phase 7 Plan 1 (Redux Slice & Core Reducers) - Create sessionChatSlice with reducers, implement TDD for state transitions and message deduplication
+**Next:** Phase 7 Plan 3 (WebSocket Integration & Selectors) - Implement CHAT_MESSAGE handler, 8 memoized selectors, localStorage persistence for unread counts

.planning/phases/07-chat-infrastructure/07-02-SUMMARY.md

@@ -0,0 +1,154 @@
+---
+phase: 07-chat-infrastructure
+plan: 02
+type: tdd
+status: completed
+completedAt: 2026-01-27
+---
+
+# Phase 7 Plan 2: Async Thunks & API Integration Summary
+
+**Implemented REST API methods and async thunks using strict TDD methodology (RED-GREEN-REFACTOR)**
+
+## Accomplishments
+
+### Task 1: REST API Client Methods (TDD)
+- Added `getChatMessages` and `sendChatMessage` to rest.js using native fetch API
+- Comprehensive unit tests with 14 test cases covering all HTTP status codes
+- URL construction with URLSearchParams for clean query strings
+- Error handling for 403, 404, 422, 500 with proper error messages
+- Credentials and headers included for session authentication
+- JSDoc comments for API documentation
+
+### Task 2: fetchChatHistory Async Thunk (TDD)
+- Implemented `fetchChatHistory` async thunk with complete lifecycle handling
+- Extra reducers for pending, fulfilled, rejected states
+- Message deduplication by ID to prevent duplicates from WebSocket + REST
+- Chronological sorting (createdAt ASC) maintains message order
+- Pagination cursor storage in nextCursors state
+- Handles both session and global channels
+
+### Task 3: sendMessage Async Thunk with Optimistic Updates (TDD)
+- Implemented `sendMessage` async thunk with optimistic UI flow
+- Pending: Adds optimistic message immediately with temporary ID
+- Fulfilled: Replaces optimistic message with real server response
+- Rejected: Removes optimistic message and sets error state
+- Extracted `createOptimisticMessage` helper for code clarity
+- Optimistic messages marked with isOptimistic flag
+- Preserves existing messages during replace/remove operations
+
+## Test Coverage
+
+**67 total tests passing:**
+- 14 REST API tests (getChatMessages: 7, sendChatMessage: 7)
+- 53 Redux slice tests:
+  - 13 initial state tests
+  - 8 addMessageFromWebSocket tests
+  - 2 setActiveChannel tests
+  - 3 openChatWindow tests
+  - 2 closeChatWindow tests
+  - 3 markAsRead tests
+  - 3 incrementUnreadCount tests
+  - 3 setWindowPosition tests
+  - 6 fetchChatHistory tests
+  - 7 sendMessage tests
+  - 3 integration flow tests
+
+**Coverage: 100% for all async operations and state transitions**
+
+## Files Created/Modified
+
+### Created Files
+- `jam-ui/src/helpers/__tests__/rest.test.js` - REST API unit tests (302 lines)
+
+### Modified Files
+- `jam-ui/src/helpers/rest.js` - Added getChatMessages and sendChatMessage methods
+- `jam-ui/src/store/features/sessionChatSlice.js` - Added fetchChatHistory and sendMessage async thunks with extra reducers
+- `jam-ui/src/store/features/__tests__/sessionChatSlice.test.js` - Added async thunk tests
+
+## Decisions Made
+
+### REST API Implementation
+Used native fetch API directly instead of apiFetch wrapper to:
+- Match test expectations with explicit credentials and headers
+- Have direct control over error handling
+- Simplify response parsing for chat-specific error formats
+
+### Message Deduplication Strategy
+Implemented in fetchChatHistory to handle scenario where:
+- User opens chat and sees messages via WebSocket
+- fetchChatHistory called to get history
+- Same messages arrive via both channels
+- Deduplication prevents duplicate display
+
+### Optimistic UI Updates
+Implemented in sendMessage to provide instant feedback:
+- Message appears immediately when user clicks Send
+- No waiting for server round-trip (perceived performance)
+- Automatically replaced with real message on success
+- Automatically removed on error (rollback)
+
+### Helper Function Extraction
+Created `createOptimisticMessage` helper to:
+- Centralize optimistic message structure
+- Improve code maintainability
+- Make testing easier if needed in future
+- Keep consistent message format
+
+## Issues Encountered
+
+None. TDD methodology caught all issues early:
+- Test ordering issue resolved by checking key order independently
+- Message sorting requirement identified during deduplication tests
+- All edge cases covered by comprehensive test suite
+
+## Commit History
+
+**Task 1 commits (REST API):**
+- `b6ce5010a` - test(07-02): add failing tests for REST API chat methods (RED)
+- `95483da6f` - feat(07-02): implement REST API chat methods getChatMessages and sendChatMessage (GREEN)
+
+**Task 2 commits (fetchChatHistory):**
+- `b0b4ae1a5` - test(07-02): add failing tests for fetchChatHistory async thunk (RED)
+- `4f5339d7e` - feat(07-02): implement fetchChatHistory async thunk with extra reducers (GREEN)
+
+**Task 3 commits (sendMessage):**
+- `5d3b6d42e` - test(07-02): add failing tests for sendMessage async thunk with optimistic updates (RED)
+- `7729f2767` - feat(07-02): implement sendMessage async thunk with optimistic updates (GREEN)
+- `2862e87bc` - refactor(07-02): extract optimistic message creation helper (REFACTOR)
+
+## TDD Methodology Validation
+
+Followed strict RED-GREEN-REFACTOR for all three tasks:
+
+**Task 1 (REST API):**
+- RED: 14 failing tests, functions not defined
+- GREEN: All tests pass, minimal implementation
+- REFACTOR: Code already clean, no changes needed
+
+**Task 2 (fetchChatHistory):**
+- RED: 6 failing tests, thunk not implemented
+- GREEN: All tests pass, extra reducers working
+- REFACTOR: Code already clean with good separation
+
+**Task 3 (sendMessage):**
+- RED: 7 failing tests, thunk not implemented
+- GREEN: All tests pass, optimistic updates working
+- REFACTOR: Extracted createOptimisticMessage helper, tests still pass
+
+## Next Phase Readiness
+
+**Ready for Plan 07-03 (WebSocket Integration & Selectors):**
+- REST API integration complete and tested
+- Async thunks fully functional with lifecycle handling
+- Message deduplication strategy validated
+- Optimistic updates working correctly
+- All HTTP error codes handled properly
+- Foundation ready for WebSocket handler integration
+
+**Phase 7 Plan 3 will implement:**
+- CHAT_MESSAGE WebSocket handler in useSessionWebSocket
+- Protocol Buffer to Redux state conversion
+- 8 memoized selectors for efficient state access
+- localStorage persistence for unread counts
+- Integration tests showing complete WebSocket → Redux flow