---
phase: 14-chat-integration-and-display
plan: 02
subsystem: ui
tags: [react, s3, rest-api, signed-urls, responsive-design]

# Dependency graph
requires:
  - phase: 14-01
    provides: "Attachment message detection and visual distinction in chat"
  - phase: 13-02
    provides: "getMusicNotationUrl REST helper for signed URL fetching"
provides:
  - "Clickable attachment links with signed S3 URL fetching"
  - "Responsive layout with filename truncation for long names"
  - "Browser-native file display/download based on Content-Type"
affects: [15-attachment-sync-and-history, 16-error-handling-and-polish]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "useCallback with loading state to prevent rapid clicks"
    - "window.open with target='_blank' for signed URLs"
    - "Flex layout with minWidth: 0 for text truncation"
    - "Title attribute for full filename on hover"

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

key-decisions:
  - "Fetch signed URL on click (not pre-fetch) to avoid URL expiration"
  - "Use loading state (isLoadingUrl) to prevent rapid multiple clicks"
  - "Browser handles file display based on Content-Type (no custom viewer)"
  - "Truncate filename with CSS (maxWidth, textOverflow: ellipsis)"

patterns-established:
  - "Signed URL pattern: fetch on demand, open in new tab, browser handles display"
  - "Responsive text truncation: minWidth: 0 on flex parent, title for hover"

# Metrics
duration: 4min
completed: 2026-02-05
---

# Phase 14 Plan 2: Clickable Links & Responsive Layout Summary

**Attachment filenames are clickable links that fetch signed S3 URLs and open in new browser tabs with responsive layout and graceful filename truncation**

## Performance

- **Duration:** 4 min
- **Started:** 2026-02-05T19:20:19Z
- **Completed:** 2026-02-05T19:24:19Z
- **Tasks:** 3 (2 implementation + 1 checkpoint)
- **Files modified:** 1

## Accomplishments
- Clickable attachment links fetch signed S3 URLs on demand and open in new browser tabs
- Browser-native file handling (PDF viewer, image display, audio player, download)
- Responsive layout with filename truncation (ellipsis) for long filenames
- Full filename shown on hover via title attribute
- Loading state prevents rapid multiple clicks

## Task Commits

Each task was committed atomically:

1. **Task 1: Add click handler to fetch signed URL and open file** - `91cac19` (feat)
2. **Task 2: Add responsive styling with filename truncation** - `1143048` (feat)
3. **Task 3: Human verification checkpoint** - Verified (user approved all checks)

**Plan metadata:** Will be committed with SUMMARY.md

## Files Created/Modified
- `jam-ui/src/components/client/chat/JKChatMessage.js` - Added handleAttachmentClick with getMusicNotationUrl integration, responsive styling with filename truncation

## Decisions Made

**1. Fetch signed URL on click (not pre-fetch)**
- Rationale: S3 signed URLs expire in 120 seconds (per backend research). Pre-fetching would cause URLs to expire before user clicks.
- Implementation: handleAttachmentClick calls getMusicNotationUrl on demand

**2. Browser-native file handling**
- Rationale: Backend sets Content-Type and Content-Disposition appropriately. No need for custom file viewer.
- Implementation: window.open(url, '_blank') and browser handles display/download based on file type

**3. Loading state to prevent rapid clicks**
- Rationale: Prevent multiple simultaneous API calls for same attachment
- Implementation: isLoadingUrl state with cursor: 'wait' styling

**4. CSS-based filename truncation**
- Rationale: Works responsively without JavaScript measurement
- Implementation: maxWidth + textOverflow: ellipsis + title attribute for hover

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered

None

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness

Phase 14 (Chat Integration and Display) is now COMPLETE. All 2 plans delivered:
- 14-01: Attachment message display with visual distinction (light blue background, metadata)
- 14-02: Clickable links and responsive layout (this plan)

**Ready for Phase 15:** Attachment sync and history (ensuring attachments persist correctly across WebSocket and REST API paths)

**Known capabilities:**
- Attachment messages display correctly in chat with visual distinction
- Filenames are clickable and fetch signed S3 URLs on demand
- Browser handles file display/download based on Content-Type
- Responsive layout works at different window sizes
- Long filenames truncate gracefully with full name on hover

**No blockers or concerns**

---
*Phase: 14-chat-integration-and-display*
*Completed: 2026-02-05*
