Scaffold Bulk Participant List Widget
epic-proxy-activity-registration-ui-task-001 — Create the base BulkParticipantList widget as a scrollable Flutter ListView with a typed participant model, empty-state placeholder, and slot for per-row action controls. Establish the widget's public API (participants list, onRemove callback) and wire it into the app's widget tree.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 12 - 5 tasks
Can start after Tier 11 completes
Implementation Notes
Place the widget at `lib/features/bulk_registration/widgets/bulk_participant_list.dart` and the model at `lib/features/bulk_registration/models/bulk_participant.dart`. Keep BulkParticipantRow as a private sub-widget in the same file initially — extract to its own file only when it grows beyond ~60 lines. Use the app's existing `AppDesignTokens` (or equivalent constants class) for all spacing and typography values to stay consistent with the rest of the UI. The empty-state placeholder should use the same pattern as other empty states in the app (check Contacts list for reference).
Do not use `key` parameters unless required for animation — add them in task-003 when Dismissible is introduced. Register BulkParticipant as an equatable or freezed class so that list comparison works correctly in BLoC state.
Testing Requirements
Widget tests using flutter_test and WidgetTester. Test file: `test/widgets/bulk_participant_list_test.dart`. Required test cases: (1) empty list renders empty-state text, (2) list of 3 participants renders 3 rows with correct names, (3) tapping the trailing slot area does not throw (future-proofing), (4) widget rebuilds correctly when participants prop changes. Use `find.text()` and `find.byType()` for assertions.
Pump the widget inside a MaterialApp with a mock design token theme. Target: 100% branch coverage for BulkParticipantList.
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.