Implement Proxy Audit Logger Infrastructure
epic-coordinator-proxy-registration-bulk-orchestration-task-003 — Create the ProxyAuditLogger infrastructure component that records all proxy registration events to a dedicated audit log table. Log entry creation, success, partial failure, and full failure events with timestamps, coordinator ID, mentor IDs, and error details. Ensure the logger is non-blocking and uses fire-and-forget async writes to avoid impacting submission latency.
Acceptance Criteria
Technical Requirements
Implementation Notes
Use `unawaited()` from `dart:async` explicitly rather than omitting `await` silently — this makes the fire-and-forget intent clear and avoids linter warnings. Define a sealed `ProxyAuditEvent` class hierarchy so each event type carries only the fields it needs. Keep the logger completely stateless: it receives all context as parameters. Supabase RLS policies should be defined in a migration file, not applied manually.
Avoid logging full mentor profile data — only IDs. Consider a local in-memory queue with a background flush if offline resilience becomes a requirement in a later phase.
Testing Requirements
Unit tests using flutter_test with a mocked Supabase client. Test all four log method signatures produce correct payload shapes. Test that a thrown exception in the Supabase client is swallowed and does not propagate. Test that unawaited calls do not block the calling function.
Integration test (TestFlight build) verifying rows appear in proxy_audit_log after a real submission flow.
Partial failures in bulk registration — where some mentors succeed and others fail — create a complex UX state that is easy to mishandle. If the UI does not clearly communicate which records succeeded and which failed, coordinators may re-submit already-saved records (creating duplicates) or miss failed records entirely (creating underreporting).
Mitigation & Contingency
Mitigation: Design the per-mentor result screen as a primary deliverable of this epic, not an afterthought. Use a clear list view with success/failure indicators per mentor name, and offer a 'Retry failed' action that pre-selects only the failed mentors for resubmission.
Contingency: If partial failure UX proves too complex to deliver within scope, implement a simpler all-or-nothing submission mode for the initial release with a clear error message listing which mentors failed, and defer the partial-retry UI to a follow-up sprint.
Submitting proxy records for a large group (e.g., 30+ mentors) as individual Supabase inserts may cause latency issues or hit rate limits, degrading the coordinator experience and potentially causing timeout failures that leave data in an inconsistent state.
Mitigation & Contingency
Mitigation: Implement the BulkRegistrationOrchestrator to batch inserts using a Supabase RPC call that accepts an array of proxy records, reducing round-trips to a single network call. Add progress indication using a stream of per-record results if the RPC supports it.
Contingency: If the RPC approach is blocked by Supabase limitations, fall back to chunked parallel inserts (5 records per batch) with retry logic, capping total submission time and surface a progress bar to manage coordinator expectations.
Unifying state management for both single and bulk proxy flows in a single BLoC risks state leakage between flows — for example, a previously selected mentor list persisting when a coordinator switches from bulk to single mode — causing confusing UI states or incorrect submissions.
Mitigation & Contingency
Mitigation: Define separate, named state subtrees within the BLoC for single-proxy state and bulk-proxy state, with explicit reset events triggered on flow entry. Write unit tests for state isolation scenarios using the bloc_test package.
Contingency: If unified BLoC state becomes unmanageable, split into two separate BLoCs (ProxySingleRegistrationBLoC and ProxyBulkRegistrationBLoC) sharing only common events via a parent coordinator Cubit.