---
phase: 13-file-upload-infrastructure
plan: 03
subsystem: ui
tags: [react, file-upload, validation, upload-progress, session-toolbar, chat-ui]

# Dependency graph
requires:
  - phase: 13-01
    provides: attachmentValidation.js service with validateFile()
  - phase: 13-02
    provides: uploadAttachment thunk, upload state selectors
  - phase: 08-chat-window-ui
    provides: JKSessionChatWindow, JKChatMessageList components
provides:
  - Functional Attach button in session toolbar
  - File selection with pre-upload validation
  - Upload progress display in chat window
  - Complete file upload user flow
affects: [14-attachment-display, future-attachment-features]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Hidden file input + visible button trigger pattern"
    - "Pre-upload validation prevents wasted network requests"
    - "Auto-open chat window on upload start for progress visibility"
    - "Toast notifications for validation and upload errors"
    - "Conditional button text and disabled state during upload"

key-files:
  created:
    - jam-ui/src/components/client/chat/JKChatUploadProgress.js
  modified:
    - jam-ui/src/components/client/JKSessionScreen.js
    - jam-ui/src/components/client/chat/JKChatMessageList.js

key-decisions:
  - "Attach button in session toolbar (per REQ-1.1), NOT in chat composer"
  - "File validation happens before upload dispatch (fail-fast, better UX)"
  - "Chat window opens automatically on upload start for progress visibility"
  - "Upload progress shown as system message at bottom of chat"

patterns-established:
  - "File upload pattern: hidden input + ref + visible button trigger"
  - "Pre-upload validation with immediate toast error feedback"
  - "Upload progress component styled as system message (not user message)"

# Metrics
duration: 7min (implementation only, excluding human verification)
completed: 2026-02-05
---

# Phase 13 Plan 03: File Upload UI Integration Summary

**Functional Attach button in session toolbar with file validation, upload dispatch, and progress display in chat window**

## Performance

- **Duration:** ~7 min (implementation) + user verification
- **Started:** 2026-02-05T05:34:35Z
- **Completed:** 2026-02-05T13:48:00Z (including verification)
- **Tasks:** 4 (3 auto + 1 checkpoint)
- **Files modified:** 3

## Accomplishments
- Attach button in session toolbar opens OS file dialog (REQ-1.1)
- Pre-upload file validation with immediate error feedback (REQ-1.2, REQ-1.3)
- Upload progress display in chat window with "Uploading [filename]..." message (REQ-1.4)
- Complete file upload flow from button click to backend API call
- User verification confirmed: upload works correctly, API returns 201 Created

## Task Commits

1. **Task 1: Wire up Attach button in session toolbar** - `7455e2ec2` (feat)
   - Added imports for uploadAttachment, validateFile, and upload selectors
   - Created attachFileInputRef for hidden file input
   - Implemented handleAttachClick and handleFileSelect callbacks
   - Added useEffect for upload error toast display
   - Added hidden file input with accept attribute
   - Updated Attach button with onClick, disabled state, and dynamic text

2. **Task 2: Create upload progress component** - `cd2d79b19` (feat)
   - Created JKChatUploadProgress component with Spinner and filename
   - Styled as system message (gray background, italic text)
   - 42 lines including component, PropTypes, and displayName

3. **Task 3: Display upload progress in chat** - `f2c07faed` (feat)
   - Added upload state selectors to JKChatMessageList
   - Imported and rendered JKChatUploadProgress component
   - Conditional rendering when isUploading && uploadFileName

4. **Bug Fix: ESLint optional chaining errors** - `edf74f724` (fix)
   - Found during user verification
   - Replaced optional chaining with explicit if checks
   - Modified: jam-ui/src/components/client/JKSessionScreen.js

5. **Bug Fix: Duplicate /api/ prefix in endpoint URL** - `b1ed2247b` (fix)
   - Found during user verification (backend 404 error)
   - Removed /api/ prefix (already in REACT_APP_API_BASE_URL)
   - Modified: jam-ui/src/helpers/rest.js

6. **Task 4: Human verification checkpoint** - APPROVED
   - User confirmed: File dialog opens on button click
   - User confirmed: Invalid files show error toast (no upload)
   - User confirmed: Valid files trigger upload with progress shown in chat
   - User confirmed: Backend API returns 201 Created for valid uploads

**Plan metadata:** `ff6042e88` (docs: complete plan)

## Files Created/Modified
- `jam-ui/src/components/client/JKSessionScreen.js` - Attach button functionality with validation and upload dispatch
- `jam-ui/src/components/client/chat/JKChatUploadProgress.js` - Upload progress indicator component (NEW)
- `jam-ui/src/components/client/chat/JKChatMessageList.js` - Upload progress display integration

## Decisions Made

**1. Attach button location: Session toolbar (NOT chat composer)**
- **Requirement:** REQ-1.1 explicitly states "Add 'Attach' button to session toolbar (top navigation)"
- **Implementation:** Button added next to Chat, Open, Record buttons in JKSessionScreen toolbar
- **Rationale:** Consistent with session-level controls, easily accessible without opening chat window
- **User verification:** CONFIRMED - button appears in toolbar as expected

**2. Pre-upload validation before dispatch**
- **Pattern:** validateFile() runs before dispatch(uploadAttachment())
- **Rationale:** Prevents wasted network requests for invalid files, provides immediate user feedback
- **Implementation:** Error toast shows immediately for invalid size/type, no backend call made
- **User verification:** CONFIRMED - invalid files show error toast without upload attempt

**3. Auto-open chat window on upload start**
- **Pattern:** dispatch(openModal('chat')) before dispatch(uploadAttachment())
- **Rationale:** User needs to see upload progress, don't force manual window open
- **Implementation:** Chat window opens automatically when valid file selected
- **Trade-off:** Might surprise user, but better than hidden progress

**4. Upload progress as system message**
- **Pattern:** JKChatUploadProgress styled differently from JKChatMessage
- **Rationale:** Upload progress is transient UI feedback, not a permanent chat message
- **Styling:** Gray background, italic text, spinner icon - visually distinct
- **Position:** Bottom of message list for easy visibility during auto-scroll

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 1 - Bug] ESLint no-unused-expressions errors**
- **Found during:** User verification (Task 4)
- **Issue:** Optional chaining expressions (attachFileInputRef.current?.click()) violated ESLint configuration
- **Fix:** Replaced with explicit if checks: `if (attachFileInputRef.current) { attachFileInputRef.current.click(); }`
- **Files modified:** jam-ui/src/components/client/JKSessionScreen.js
- **Verification:** ESLint errors resolved, file dialog still opens correctly
- **Committed in:** edf74f724 (separate fix commit during verification)

**2. [Rule 1 - Bug] Duplicate /api/ prefix in REST endpoint URL**
- **Found during:** User verification (Task 4) - backend returning 404
- **Issue:** uploadMusicNotation used `/api/music_notations` but REACT_APP_API_BASE_URL already includes `/api`, resulting in `/api/api/music_notations`
- **Fix:** Changed endpoint to `music_notations` (without /api/ prefix)
- **Files modified:** jam-ui/src/helpers/rest.js
- **Verification:** Backend returns 201 Created, upload succeeds
- **Committed in:** b1ed2247b (separate fix commit during verification)

---

**Total deviations:** 2 auto-fixed bugs (both found during user verification)
**Impact on plan:** Both bugs were correctness issues discovered during verification. Fixes were minimal (1-line changes) and did not affect scope.

## Issues Encountered

**1. Build verification not possible due to Node.js/webpack version mismatch**
- **Issue:** `npm run build` fails with OpenSSL error (Node.js v23 incompatible with old webpack)
- **Workaround:** Used `node -c` for syntax checking instead
- **Impact:** No impact on functionality - syntax checks passed, user verification confirmed working code
- **Note:** Pre-existing issue in codebase, unrelated to this plan

## User Verification Results

**All 4 verification points APPROVED:**

1. ✅ **File dialog opens:** Attach button in toolbar opens OS file selector
2. ✅ **Invalid file handling:** Large files (>10 MB) and wrong types (.exe, .zip) show error toast
3. ✅ **Valid file upload:** .pdf, .png, .txt files trigger upload with progress display
4. ✅ **Backend integration:** Rails logs show `POST /api/music_notations 201 Created`

**User observations:**
- No error toast after upload (expected - backend accepts file)
- "Uploading..." progress message disappears after completion (expected behavior)
- New message appears in chat (basic display without file info - Phase 14 will enhance this)
- Backend API integration working correctly

## Next Phase Readiness

**Ready for Phase 14 (Attachment Message Display):**
- Upload flow complete and verified
- Backend API integration confirmed (201 Created)
- Chat messages with attachments being created (basic display)
- WebSocket message delivery working (user sees new message)

**Next phase will:**
- Enhance JKChatMessage to detect and display attachment metadata
- Add file download functionality (signed URLs)
- Add file type icons and formatting
- Add attachment error handling in message display

**No blockers or concerns.**

**Remaining work in Phase 13:** None - all 3 plans complete

---
*Phase: 13-file-upload-infrastructure*
*Plan: 03 (FINAL PLAN IN PHASE)*
*Completed: 2026-02-05*
