---
phase: 09-scan-cancellation-keyboard-shortcuts
plan: 03
subsystem: ui
tags: [lit, scan-control, dialog, wails-binding, config-page]

# Dependency graph
requires:
  - phase: 09-scan-cancellation-keyboard-shortcuts
    provides: CancelScan, PauseScan, ResumeScan Wails bindings and scan lifecycle events
provides:
  - Pause/Resume/Cancel scan buttons in config page during active scan
  - Cancel confirmation dialog with Keep/Discard/Continue options
  - Scan paused/resumed/cancelled event handling in frontend
affects: [09-scan-cancellation-keyboard-shortcuts]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Conditional button rendering based on scan state (scanning/paused toggles button set)"
    - "Modal dialog overlay with click-outside dismiss via stopPropagation"

key-files:
  created: []
  modified:
    - frontend/src/components/config-page/config-page.ts
    - frontend/wailsjs/go/library/Library.d.ts
    - frontend/wailsjs/go/library/Library.js

key-decisions:
  - "Discard option shows informational message rather than auto-triggering FullRescan — safer for v1.1"
  - "Scan buttons swap entirely during scan (Pause/Cancel replace Soft Scan/Full Rescan) for clear affordance"

patterns-established:
  - "Cancel confirmation dialog pattern: overlay + stopPropagation + three-option (keep/discard/continue) design"

requirements-completed: [SCAN-01, SCAN-02, SCAN-03]

# Metrics
duration: 2min
completed: 2026-03-07
---

# Phase 9 Plan 03: Scan Control UI Summary

**Pause/Resume/Cancel scan buttons with modal confirmation dialog wired to backend Wails bindings and scan lifecycle events**

## Performance

- **Duration:** 2 min
- **Started:** 2026-03-07T02:52:25Z
- **Completed:** 2026-03-07T02:55:18Z
- **Tasks:** 1
- **Files modified:** 3

## Accomplishments
- Scan buttons dynamically swap between Soft Scan/Full Rescan (idle) and Pause/Cancel (active scan)
- Pause toggles to Resume when scan is paused, with accent-colored status bar message
- Cancel shows modal dialog with Keep/Discard/Continue options and track count
- Event handlers for LibraryScanPaused/Resumed/Cancelled update component state
- Added CancelScan/PauseScan/ResumeScan Wails binding stubs for TypeScript compilation
- Added `cancelled` field to frontend ScanMetrics interface

## Task Commits

Each task was committed atomically:

1. **Task 1: Add scan control state, event handlers, and UI buttons** - `3914369` (feat)

## Files Created/Modified
- `frontend/src/components/config-page/config-page.ts` - Scan control state, event handlers, Pause/Resume/Cancel buttons, cancel dialog, CSS styles
- `frontend/wailsjs/go/library/Library.d.ts` - CancelScan, PauseScan, ResumeScan, IsScanActive, IsScanPaused type declarations
- `frontend/wailsjs/go/library/Library.js` - CancelScan, PauseScan, ResumeScan, IsScanActive, IsScanPaused runtime bindings

## Decisions Made
- Discard option shows informational message ("run Full Rescan for clean library") rather than automatically triggering a rescan — safer and less surprising for users
- Buttons fully swap during scan rather than showing disabled states — clearer UX affordance
- Cancel dialog uses three options (Keep N tracks / Discard / Continue Scanning) for maximum user control

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 3 - Blocking] Added Wails binding stubs for scan control methods**
- **Found during:** Task 1 (imports)
- **Issue:** CancelScan/PauseScan/ResumeScan not in generated Wails binding files — TypeScript would fail to compile
- **Fix:** Added function declarations and runtime implementations to Library.d.ts and Library.js
- **Files modified:** frontend/wailsjs/go/library/Library.d.ts, frontend/wailsjs/go/library/Library.js
- **Verification:** `npx tsc --noEmit` passes
- **Committed in:** 3914369 (part of task commit)

**2. [Rule 3 - Blocking] Included untracked shortcut-capture.ts from Plan 02**
- **Found during:** Task 1 (commit)
- **Issue:** `shortcut-capture.ts` was created in Plan 02 but not committed; lefthook pre-commit hook included it in this commit
- **Fix:** File included in commit — it's a valid component from the keyboard shortcuts plan
- **Files modified:** frontend/src/components/config-page/shortcut-capture.ts
- **Verification:** TypeScript compiles cleanly
- **Committed in:** 3914369 (part of task commit)

---

**Total deviations:** 2 auto-fixed (2 blocking)
**Impact on plan:** Both fixes necessary for compilation. No scope creep.

## Issues Encountered
None

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Scan control UI complete, ready for Plan 04 (keyboard shortcut UI) and Plan 05 (integration)
- All scan control buttons wired to backend Wails bindings
- Events properly handled for all scan lifecycle states

## Self-Check: PASSED

- All 3 key files verified on disk (config-page.ts, Library.d.ts, Library.js)
- Task commit found in git log (3914369)
- Docs commit: 85573e8

---
*Phase: 09-scan-cancellation-keyboard-shortcuts*
*Completed: 2026-03-07*