Implement DriverAssignmentRepository CRUD operations
epic-driver-and-confidentiality-management-foundation-task-004 — Implement the Dart repository for driver assignments with methods for creating, reading, updating (status changes), and soft-deleting assignments. Ensure all queries are org-scoped and respect RLS. Support fetching assignments by driver ID and by assignee contact ID for history display.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 1 - 540 tasks
Can start after Tier 0 completes
Implementation Notes
Define AssignmentStatus as a Dart enum with a toJson()/fromJson() string mapping matching the database CHECK constraint values exactly. For softDelete, use `.update({'deleted_at': DateTime.now().toUtc().toIso8601String()})` — or better, use a Supabase RPC function that sets `now()` server-side to avoid clock skew issues. For getAssignmentsByDriver and getAssignmentsByContact, filter soft-deleted rows with `.is_('deleted_at', null)`. The getAssignmentById intentionally omits the deleted_at filter to support history display — document this clearly in a code comment.
Follow the same Riverpod provider pattern established by DeclarationTemplateRepository (task-002) for consistency. Use `.select('*').single()` for create/update operations to return the full updated entity in one round-trip.
Testing Requirements
Unit tests with mocked Supabase client using flutter_test covering: (1) createAssignment maps response to DriverAssignment model correctly, (2) getAssignmentsByDriver filters by driverId and excludes soft-deleted rows, (3) getAssignmentsByContact filters by contactId and excludes soft-deleted rows, (4) updateStatus sends correct status value only, (5) softDelete sends deleted_at update, (6) getAssignmentById includes soft-deleted rows, (7) Supabase error propagates as RepositoryException, (8) empty result returns empty list not null. Aim for 100% method coverage.
Row-level security policies for driver assignments and declarations must correctly scope data to the coordinator's chapter without leaking records across organizations. An incorrect RLS predicate could silently return empty result sets or, worse, expose cross-org data, both of which are difficult to detect in unit tests.
Mitigation & Contingency
Mitigation: Write dedicated RLS integration test scenarios with multiple org fixtures asserting both data isolation and correct data visibility. Use Supabase's built-in policy testing utilities and review policies with a second developer.
Contingency: If RLS policies prove too complex to get right quickly, implement application-layer org scoping as a temporary guard while RLS is fixed in a follow-up, with an explicit security review gate before production deployment.
The declaration audit logger must produce tamper-evident records. If the database allows updates or deletes on audit rows, the compliance guarantee is broken. Supabase does not natively prevent row deletion by default.
Mitigation & Contingency
Mitigation: Implement an insert-only RLS policy on the audit table that denies UPDATE and DELETE for all roles including the service role. Add a database trigger that rejects mutation attempts and logs the attempt itself.
Contingency: If immutability cannot be enforced at the database level within the sprint, store audit entries in an append-only Supabase Edge Function log stream as a temporary alternative, with a migration plan to the proper table once constraints are implemented.
The org-feature-flag-service caches flag values to avoid repeated database reads. If the cache is not invalidated promptly after an admin toggles the flag, coordinators may see stale UI state — either seeing driver features when they should not, or not seeing them when they should.
Mitigation & Contingency
Mitigation: Use a Supabase Realtime subscription to listen for changes on the driver_feature_flag_config table and invalidate the in-memory cache immediately on change. Set a short TTL (60 seconds) as a safety net.
Contingency: If Realtime subscription proves unreliable, expose a manual cache-bust endpoint accessible from the admin toggle action, ensuring the cache is cleared synchronously on every flag change.