Add Single-Select and Multi-Select Modes to Selector
epic-proxy-activity-registration-ui-task-009 — Extend ProxyPeerMentorSelector to support a mode prop switching between single-select (radio-style, used in proxy-registration-screen) and multi-select (checkbox-style with chips, used in bulk-registration-screen). Chips must display mentor name and provide individual removal. Ensure mode-appropriate keyboard and screen reader behavior.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 14 - 3 tasks
Can start after Tier 13 completes
Implementation Notes
Store the selected mentor(s) list in the Riverpod notifier alongside search state. For single mode, after selection update selectedMentors = [selected] and set TextField text to mentor.name (make it read-only or use a display controller). For multi mode, keep TextField editable for continued searching while chips display below. Use InputChip with onDeleted callback for chip removal.
In multi mode, pass selectedMentors to PeerMentorResultTile so it can show a checked state and toggle on tap (if already in list, remove; if not, add). Implement a FocusNode list for chips with RawKeyboardListener detecting LogicalKeyboardKey.delete/backspace for chip keyboard removal. Apply a maximum selection guard (e.g., maxSelections: 50) configurable via constructor. Chip text should use AppTextStyle.labelSmall with design token colors.
Coordinate with the parent screens (proxy-registration-screen and bulk-registration-screen) to confirm which mode each uses and ensure the widget's public API matches their expectations before finalizing constructor signatures.
Testing Requirements
Widget tests: (1) single mode — select mentor → TextField shows name, overlay closes; (2) single mode — select different mentor → previous selection replaced; (3) multi mode — select mentor → chip appears, overlay stays open; (4) multi mode — select same mentor again → deselects (chip removed); (5) tap chip remove icon → mentor removed from selection, onChanged called; (6) Wrap layout with 5+ chips renders without overflow at 375px screen width; (7) verify onChanged called with correct data type (single: PeerMentor?, multi: List
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.