Implement PeerMentorStatsList widget
epic-coordinator-statistics-dashboard-ui-task-003 — Build the PeerMentorStatsList widget that renders a scrollable list of peer mentor rows with name, activity count, hours total, and last-activity date. Include sort controls (by name, activity count, hours) and an inline search bar. Each row is tappable for per-mentor drill-down. Support loading skeleton and empty-state views. Ensure adequate touch targets and semantic labels.
Acceptance Criteria
Technical Requirements
Implementation Notes
Manage sort state and search query in a local ValueNotifier
Each PeerMentorStatsRow should be a ListTile subclass or a custom Row in an InkWell; wrap in a ConstrainedBox(minHeight: 44) or set the ListTile.minVerticalPadding. For the search bar, use a TextField with a debounce of 150 ms to avoid excessive rebuilds on fast typing — implement debounce with a Timer.periodic or the rxdart debounceTime operator if already in pubspec. For the empty state, use a Column with a SizedBox(height: 48) SVG/Icon, a Text with the appropriate message, and optional retry button. Format hours as: final h = totalMinutes ~/ 60; final m = totalMinutes % 60; return m > 0 ?
'${h}h ${m}m' : '${h}h'. Format last-activity date using DateFormat.yMd(locale) from the intl package.
Testing Requirements
Widget tests using flutter_test. Test groups: rendering (correct fields shown per row, formatted values, sort bar visible, search bar visible), sorting (tapping each sort column produces correctly ordered list, toggling direction reverses order, active column indicator updates), search (typing filters list case-insensitively, clearing restores full list, no-match triggers empty state with 'not found' message), loading state (skeleton rows shown, sort and search disabled), empty state (pre-filter empty shows 'no data for period', post-filter empty shows 'no mentors found'), interaction (tapping a row calls onMentorTapped with correct value), accessibility (each row Semantics label is complete and accurate), touch targets (row height ≥ 44 px). Performance test: pump 200 rows and assert build time under 100 ms. Achieve ≥ 90 % line coverage.
PeerMentorStatsList must handle rosters of 40+ mentors efficiently. A naive ListView implementation that re-renders all rows on filter change may cause frame drops on mid-range devices, degrading the experience for coordinators managing large chapters.
Mitigation & Contingency
Mitigation: Use ListView.builder with const constructors for row widgets. Profile the list with Flutter DevTools on a release build against a 60-mentor dataset before submitting for review. Implement sort in the BLoC layer, not in the widget.
Contingency: If frame drops persist, introduce pagination (load 20 mentors, scroll to load more) and add a search filter to reduce visible row count in practice.
The ActivityTypeDonutChart must render org-configured activity type labels from the org-labels system. If the terminology provider is not available or returns stale labels, chart segments will display raw key strings instead of human-readable organisation-specific names, confusing coordinators.
Mitigation & Contingency
Mitigation: Always resolve labels through the OrganizationLabelsProvider before passing data to the donut chart widget. Implement a fallback that formats the raw key as a readable string (e.g., 'peer_support' → 'Peer Support') if the provider returns null.
Contingency: If the org-labels system is unavailable, display the formatted fallback label and log a warning. Do not block chart rendering on label resolution — render with fallbacks immediately.
fl_chart widgets do not natively expose semantic labels for individual bars and donut segments. Without explicit Semantics wrappers, VoiceOver and TalkBack users will receive no meaningful chart information, failing accessibility requirements critical for Blindeforbundet and NHF deployments.
Mitigation & Contingency
Mitigation: Wrap each fl_chart widget in a Semantics widget with a descriptive label summarising the chart data. Implement the data table fallback toggle from the start, not as an afterthought. Validate with VoiceOver on iOS and TalkBack on Android during development.
Contingency: If fl_chart's rendering pipeline prevents semantic overlay from working reliably, replace chart widgets with a custom Canvas-based implementation that has full semantic control, or use a different charting library with better accessibility support.
The period filter state must be preserved when navigating away from the dashboard (e.g., drilling into a mentor's detail screen and pressing back). If the BLoC is re-created on navigation, the filter resets to default, forcing coordinators to re-select their period every time they drill down, degrading operational workflow efficiency.
Mitigation & Contingency
Mitigation: Provide the StatsBloc at a route level above the dashboard screen using a BlocProvider scoped to the statistics navigation shell, not inside the screen widget itself. Verify persistence with a widget integration test that navigates away and back.
Contingency: If route-level scoping is not achievable within the current navigation architecture, persist the last-used filter to a local session store and restore it on screen re-entry.