Implement Dashboard Stat Loading in BLoC
epic-admin-portal-dashboard-ui-task-005 — Wire the AdminPortalBloc to the AdminStatisticsService for loading KPI dashboard statistics. Implement event handlers for LoadDashboardStats, RefreshStats, and ScopeChanged events. Ensure stats are reloaded when the org hierarchy scope changes. Handle loading, success, and error states in BLoC state model.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 2 - 518 tasks
Can start after Tier 1 completes
Implementation Notes
Use flutter_bloc ≥ 8.x with sealed state classes (or freezed-generated) for exhaustive pattern matching in the UI. Implement ScopeChanged with a transformer that uses `droppable()` or `restartable()` to cancel in-flight requests when scope changes rapidly. The AdminPortalBloc should hold a reference to an internal CancelableOperation or use StreamSubscription cancellation. Inject AdminStatisticsService via BlocProvider/constructor injection for testability.
Keep the BLoC thin: no business logic beyond event routing and state mapping — all data transformation belongs in AdminStatisticsService. Follow the pattern: event → emit(Loading) → await service → emit(Loaded/Error). Avoid storing raw Supabase responses in state; map to domain models before emitting.
Testing Requirements
Unit tests using flutter_test and bloc_test package. Test all event → state transitions: (1) LoadDashboardStats → loading → loaded with mock data, (2) LoadDashboardStats → loading → error with mock service throwing, (3) ScopeChanged mid-load → cancels previous → loads new scope, (4) RefreshStats → reloads even when already in loaded state. Mock AdminStatisticsService with Mockito. Assert emitted state sequences exactly.
Achieve 100% branch coverage on the BLoC event handlers. Integration test: mount AdminDashboardPage, verify BLoC emits loaded state and stat widgets render correct values.
If org node selection in AdminStateBLoC does not correctly propagate to all dependent data streams (statistics, activity log, user list, certification panel), some panels may show data from the previously selected org scope, creating a confusing and potentially dangerous mixed-scope view.
Mitigation & Contingency
Mitigation: Model org node selection as a single source of truth in AdminStateBLoC. All downstream providers derive their query parameters from this single stream via Riverpod's watch pattern. Write integration tests that verify every data stream emits a reload event when the selected node changes.
Contingency: If scope propagation bugs are detected in QA, add an explicit full-state reset on org node change (clear all cached data and refetch from scratch) as a safe but less efficient fallback until the targeted propagation is fixed.
The Admin Dashboard Screen must adapt its layout for Flutter Web (wider viewports, mouse interaction, larger grid) and mobile embedding. Flutter Web responsive layout support has historically required non-trivial workarounds, and the adaptive grid may introduce significant additional development time.
Mitigation & Contingency
Mitigation: Define breakpoints and grid behaviour in the design system before implementation. Use LayoutBuilder with explicit breakpoint constants rather than MediaQuery scattered across widgets. Prototype the web layout with a skeleton screen before implementing live data binding.
Contingency: If web layout proves intractable within sprint, deliver a mobile-first layout for all platforms initially and track a dedicated web-optimisation task for the next sprint.
A bug in the Role Assignment Panel's permission scope validation could allow an org_admin to assign roles beyond their authority (e.g., assigning super_admin to a user), representing a serious privilege escalation vulnerability.
Mitigation & Contingency
Mitigation: Enforce role assignment scope on both the client (disable unavailable roles in the panel UI) and the server (UserManagementService validates the target role is within the admin's permitted scope before persisting). Write security-focused tests that attempt out-of-scope role assignments and assert rejection.
Contingency: If an escalation vulnerability is discovered, immediately disable the role assignment panel via feature flag, revoke any incorrectly assigned roles, and deploy a server-side fix before re-enabling.