Attestation Queue Screen — list and real-time updates
epic-travel-expense-registration-ui-task-008 — Build the coordinator attestation queue screen that fetches pending expense claims via ExpenseAttestationService and displays them in a scrollable list sorted by submission date. Subscribe to the Supabase realtime channel for the expense_claims table so newly submitted claims appear without a manual refresh. Show a claim status badge (pending, approved, rejected) on each list item using the unified color system.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 5 - 253 tasks
Can start after Tier 4 completes
Implementation Notes
Use StreamSubscription from Supabase Realtime and pipe events into the BLoC via a dedicated RealtimeClaimEvent. Keep the subscription lifecycle inside the BLoC's constructor/close rather than in the widget to avoid re-subscription on rebuilds. For diffing, maintain a Map
Use the organisation labels system to localise any status strings displayed to the user. Lazy-load submitter names from a local cache (contacts already in the Contacts feature) to avoid N+1 fetches.
Testing Requirements
Widget tests using flutter_test: verify list renders correct number of items given a mocked service response; verify empty-state is shown when service returns empty list; verify status badge color maps correctly to each status value. BLoC unit tests: verify LoadQueue event triggers fetch and emits Loaded state; verify realtime INSERT event adds item to list; verify realtime UPDATE event updates existing item badge. Integration test: mount the screen against a Supabase test instance, insert a claim, assert it appears in the list within 3 seconds. Accessibility test: run flutter_test Semantics tree assertions on each list item to confirm label content.
The image_picker Flutter plugin requires platform-specific permissions (NSPhotoLibraryUsageDescription, camera permission) and behaves differently across iOS and Android versions. Permission denial or plugin misconfiguration can silently prevent receipt attachment.
Mitigation & Contingency
Mitigation: Configure all required permission strings in Info.plist and AndroidManifest.xml during initial plugin setup. Use the permission_handler package to check and request permissions before launching the picker, with clear user-facing explanations. Test on both platforms across at least two OS versions.
Contingency: If image_picker proves unreliable on a specific platform version, fall back to file_picker as an alternative that uses the OS document picker interface, which requires fewer permissions on some Android versions.
The expense form BLoC manages interconnected state across expense type selection, field visibility, receipt requirement, threshold evaluation, and submission flow. Incorrect state transitions can cause UI inconsistencies such as required receipt indicator not updating after amount change, or form appearing valid when mutual exclusion is violated.
Mitigation & Contingency
Mitigation: Model BLoC states as sealed classes with exhaustive pattern matching. Write state transition unit tests covering every combination of: type selection change, amount field change above/below threshold, receipt attachment/removal, and offline mode toggle. Use bloc_test for comprehensive state sequence assertions.
Contingency: If BLoC complexity becomes unmanageable, split into two BLoCs — one for type selection/exclusion state and one for field values/submission — coordinating via a parent provider, accepting the small overhead of inter-BLoC communication.
The expense type selector must enforce mutual exclusion visually by disabling options and showing conflict tooltips, while remaining fully accessible to screen reader users who cannot perceive visual disable states. Incorrect semantics labelling will fail WCAG 2.2 AA requirements critical for Blindeforbundet and HLF users.
Mitigation & Contingency
Mitigation: Use Flutter Semantics widgets to explicitly set disabled state and provide conflict explanations as semanticLabel strings on disabled options. Run accessibility audits with TalkBack and VoiceOver during widget development, not post-completion. Reference the project's accessibility test harness for required test coverage.
Contingency: If custom widget accessibility is difficult to certify, implement the selector as a standard Flutter Radio/Checkbox group with built-in accessibility semantics and an explanatory Text widget below each conflicting option, sacrificing visual elegance for guaranteed WCAG compliance.