Build driver assignment fee validation logic
epic-driver-and-confidentiality-management-core-services-task-005 — Implement the fee validation portion of the driver assignment service. When a coordinator registers a driver assignment with an honorarium fee, the service must compare the fee amount against the org-configured threshold. Fees at or above the threshold must trigger the expense approval workflow coordination path instead of direct assignment confirmation.
Acceptance Criteria
Technical Requirements
Implementation Notes
Represent all monetary values as int (øre / minor units) throughout the service layer to eliminate floating-point precision bugs. Define a sealed class FeeValidationResult with two subclasses: BelowThreshold and RequiresApproval. Store the org threshold in OrgSettings as honorarium_threshold_ore (integer). Implement OrgSettingsRepository as an abstract class with a SupabaseOrgSettingsRepository concrete implementation, injected via Riverpod provider — this enables easy mocking in tests.
Cache the threshold per org_id using a simple in-memory map on the service; invalidate on org settings update events. Avoid business logic in the Supabase RPC layer — keep validation in Dart for testability. The FeeValidationResult should carry the resolved threshold value so callers can display it in UI without a second fetch.
Testing Requirements
Unit tests (flutter_test) are mandatory and must achieve 100% branch coverage of the validation logic. Test the FeeValidationService in isolation using a mock OrgSettingsRepository. Parameterized tests for boundary values: threshold - 1, threshold, threshold + 1, 0, negative. Integration test: verify the Supabase RLS policy actually blocks cross-org threshold reads by running the query under a JWT from a different org — this test runs against the Supabase test project.
No UI tests required for this task.
Org-scoped encryption key management is complex. If keys are not correctly isolated per organization, a breach in one org's key could expose another org's declarations. Additionally, key rotation is not specified but may be needed for compliance, and the current implementation may not support it.
Mitigation & Contingency
Mitigation: Use Supabase Vault or a dedicated secrets management approach for org-scoped key storage. Define the key derivation strategy (per-org master key) in a security design document reviewed before implementation begins. Include key isolation tests in the test suite.
Contingency: If a full per-org key management system cannot be safely implemented within the sprint, fall back to a single platform-level encryption key with strict RLS isolation as a temporary measure, flagging the key rotation gap as a security debt item with a defined resolution milestone.
Push notification delivery to drivers depends on FCM token availability and device connectivity. If a driver has not granted notification permissions or has an expired FCM token, the declaration delivery notification will silently fail, leaving the coordinator unaware and the declaration unacknowledged.
Mitigation & Contingency
Mitigation: Implement delivery status tracking in declaration-notification-service. Fall back to in-app notification and SMS (if configured) when push delivery fails. Expose delivery failure status in the declaration status badge so coordinators can identify and manually follow up.
Contingency: If push delivery proves unreliable, implement a polling-based in-app notification fallback where drivers see pending declarations on next app open, ensuring the workflow can complete even without push notifications.
The acknowledgement service is meant to validate that the driver has fully scrolled through the declaration before confirming. Implementing reliable scroll completion detection in Flutter across different screen sizes and font sizes is technically non-trivial and could be bypassed.
Mitigation & Contingency
Mitigation: Implement scroll position tracking using ScrollController with a threshold (e.g., 95% of content height reached) and record the validated state server-side before allowing acknowledgement submission. Document the approach in the legal sign-off checkpoint noted in the feature documentation.
Contingency: If reliable scroll detection cannot be implemented within the sprint, add a mandatory reading delay timer (e.g., estimated reading time based on word count) as an alternative validation mechanism, pending legal review of the approach.
The driver assignment service must coordinate with the threshold-based expense approval workflow for fees above configured thresholds. If the expense approval workflow interface changes or is not yet stable, the integration point could break or produce incorrect routing behavior.
Mitigation & Contingency
Mitigation: Define a clear interface contract between driver-assignment-service and the expense approval workflow before implementation. Use dependency injection so the expense workflow client can be mocked in tests. Monitor the expense approval feature for interface changes.
Contingency: If the expense approval workflow interface is not stable, implement a direct database insert to the expense records table as a temporary bypass, with a flag indicating manual review is needed, until the stable interface is available.