Persist last-used activity type after registration
epic-quick-activity-registration-business-logic-task-003 — Add saveLastUsedActivityType(String activityTypeId) to RegistrationDefaultsManager that writes the ID to RegistrationPreferencesStore after each successful registration. This ensures the next wizard session pre-selects the same type, delivering the 'under two clicks' promise for repeat registrations.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 2 - 518 tasks
Can start after Tier 1 completes
Implementation Notes
The ArgumentError guard for empty strings should use assert() in debug mode and an explicit throw in production (or simply use assert with a descriptive message if the team convention uses asserts for preconditions). Do not add a guard for null — Dart's null safety enforces non-null at compile time. At the call site (activity registration Cubit), call saveLastUsedActivityType() using unawaited() from dart:async to make the fire-and-forget intent explicit and suppress lint warnings about discarded futures. Consider adding a thin integration test that exercises the full path: wizard selects activity type → registration submits → preference is written → new wizard session reads the saved default — this validates the 'under two clicks' promise end-to-end.
Testing Requirements
Unit tests using flutter_test with mocked IRegistrationPreferencesStore: test that saveLastUsedActivityType('valid-id') calls store.write(key, 'valid-id') exactly once, test that saveLastUsedActivityType('') throws ArgumentError, test that if store.write() throws, the error is caught and logged (not rethrown), test round-trip integration with RegistrationDefaultsManager using an in-memory fake store implementation (not a mock) — save then get returns the saved value. Target 100% branch coverage on this method.
The wizard Cubit manages multiple concurrent state slices (current step, each field value, submission status, error state). As the number of wizard steps grows, the state class can become unwieldy, making it difficult to reason about transitions, leading to subtle bugs where advancing a step resets a previously filled field.
Mitigation & Contingency
Mitigation: Use an immutable state model (copyWith pattern) with a separate sealed class per wizard step state. Keep the Cubit's emit calls minimal and always derive the next state from the current state to prevent accidental field resets. Document the state machine transitions explicitly in code comments.
Contingency: If state complexity becomes unmanageable, split into a parent WizardCubit (owns step navigation and submission) and per-step child Cubits (own individual field state), coordinating via a shared repository layer.
Organisation-specific compensation eligibility rules (e.g., activity type + duration thresholds) are business logic that may change independently of the app release cycle. Hardcoding these rules in ActivityRegistrationService means rule changes require a new app deployment, causing delays and potential financial errors if the deployed version uses outdated rules.
Mitigation & Contingency
Mitigation: Model compensation rules as configuration fetched from Supabase (stored per organisation), cached locally. ActivityRegistrationService reads from cache with a fallback to hardcoded defaults for offline scenarios. Design the rule schema to be extensible without code changes.
Contingency: If dynamic rules are not ready for initial release, ship with hardcoded rules and a feature flag that enables the remote-config path. Document the rule structure clearly so coordinators can trigger a rule update via a Supabase dashboard entry rather than a code deployment.
The last-used activity type stored in RegistrationPreferencesStore may become invalid if the organisation administrator deactivates that activity type between sessions. The Cubit would pre-populate a deleted type, and either the UI would show a missing item or submission would fail with a foreign-key constraint error.
Mitigation & Contingency
Mitigation: In RegistrationDefaultsManager, validate the retrieved last-used activity type ID against the current list of active types fetched from the activity type repository. If the stored ID is not in the active list, fall back to the first active type alphabetically.
Contingency: If validation cannot be performed offline, surface a non-blocking warning in the activity type step ('Your previously used activity type is no longer available') and require the user to make a new selection before advancing.