Implement Typeahead Search with Chapter Scope Filter
epic-proxy-activity-registration-ui-task-008 — Wire the ProxyPeerMentorSelector's text input to a debounced search query that fetches peer mentors filtered to the coordinator's chapter scope. Render results in a dismissible overlay list with mentor name and chapter label. Handle empty results and network errors gracefully with inline messages.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 13 - 6 tasks
Can start after Tier 12 completes
Implementation Notes
Implement debounce using a Timer in the Riverpod notifier or a custom debounce utility — cancel and restart the timer on each keystroke. The Riverpod provider should be scoped to the widget (using ref.watch inside a ConsumerStatefulWidget) and auto-disposed. Supabase query: use the Supabase Flutter client's .ilike() for case-insensitive partial match. The chapterScope parameter must be the chapter UUID (not display name) for reliable filtering.
Validate that Supabase RLS policies restrict peer_mentor queries to the authenticated coordinator's chapter — if RLS is not yet in place, add a TODO and enforce in application layer. PeerMentorResultTile should be a separate widget file to keep the selector manageable. Use ListView.builder with itemCount capped at 10 (max results from API). Ensure OverlayEntry from task-007 is updated via setState() when results arrive.
Testing Requirements
Widget tests with mocked Supabase/Riverpod provider: (1) input '<2 chars' → overlay hidden; (2) input '≥2 chars' → loading state → results rendered after debounce; (3) Supabase mock returns empty list → empty state shown; (4) Supabase mock throws → error state shown with Retry button; (5) tap result tile → onChanged called with correct PeerMentor; (6) clear input → overlay dismissed. Integration test: real Supabase test instance query with chapter_id filter returns only chapter-scoped mentors. Use fake_async package to test debounce timing without real delays.
The bulk registration screen combines pre-filled defaults, a dynamic multi-select participant list, per-participant conflict badges, and a batch submission confirmation — making it one of the most complex screens in the application. Scope creep or underestimated interaction complexity could cause the epic to exceed its estimate significantly.
Mitigation & Contingency
Mitigation: Implement the bulk screen in two vertical slices: (1) participant selection and form submission without conflict handling, (2) conflict badge rendering and override flow. Validate slice 1 with coordinators before building slice 2.
Contingency: If the full conflict review UI cannot be completed within the epic, ship the bulk screen with a simplified 'skip all duplicates' fallback mode and defer per-participant override toggles to a follow-up sprint.
The proxy-registration-bloc must manage state across two distinct flows (single proxy and bulk) with branching conflict paths, intermediate buffering of bulk participant selections, and reliable state reset. Incorrect state transitions could leave the UI in a loading or stale-conflict state after submission.
Mitigation & Contingency
Mitigation: Model the BLoC state as a sealed class hierarchy with exhaustive pattern matching in the UI. Write state-machine unit tests that exercise every valid transition and assert that invalid transitions are no-ops. Use flutter_bloc's BlocObserver in debug builds to log all transitions.
Contingency: If BLoC state bugs surface in QA, introduce an explicit ResetToIdle event triggered on screen disposal to guarantee clean state, and add a 'Start over' affordance visible to the coordinator at any conflict step.
The typeahead peer mentor selector with multi-select mode may be difficult to operate with VoiceOver/TalkBack, particularly the dynamic search results list and the selected-chip removal controls, risking WCAG 2.2 AA non-compliance for screen reader users.
Mitigation & Contingency
Mitigation: Wrap all search result items and selected chips with explicit Semantics widgets providing role, label, and selected-state announcements. Test the selector with VoiceOver on iOS and TalkBack on Android during development, not only at QA time.
Contingency: If the multi-select typeahead cannot be made fully accessible within the sprint, provide an alternative flat scrollable list with checkboxes as a fallback mode, toggled by an accessibility-settings flag.
The peer mentor selector must apply RLS chapter-scope filtering to show only mentors the coordinator is responsible for. If the Supabase query for the selector does not correctly join against the coordinator's chapter assignments, coordinators may see mentors from other chapters, violating data isolation.
Mitigation & Contingency
Mitigation: Implement the selector's data query using the same RLS-aware Supabase client used by the contact list feature, which already handles chapter-scope filtering. Write an integration test with a multi-chapter coordinator fixture asserting cross-chapter mentors are not returned.
Contingency: If a data isolation breach is discovered, immediately add a client-side chapter_id filter as a defence-in-depth measure and audit selector query logs for any unauthorised cross-chapter results.