Implement RegistrationDefaultsManager with preference persistence
epic-quick-activity-registration-business-logic-task-002 — Implement the concrete RegistrationDefaultsManager class that reads from and writes to RegistrationPreferencesStore. It must expose getDefaults() returning today's date (DateTime.now()), 30-minute duration, and the last-used activity type retrieved from local storage. On first run with no stored preference, fall back to a sensible null-safe default so the happy path always has a value.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 1 - 540 tasks
Can start after Tier 0 completes
Implementation Notes
Introduce a thin IRegistrationPreferencesStore abstraction around shared_preferences (one read method, one write method, one clear method) — this makes unit testing trivial without initialising Flutter binding. Inject it via constructor. For the date field, call DateTime.now() inside getDefaults() on each invocation rather than caching it, so the date is always today even if the manager is a long-lived singleton. Use a constant string key (e.g.
'last_used_activity_type_id') for the preferences key — define it as a private static const to avoid typo-related bugs. The error handling in getDefaults() should use a try/catch around the store read only, not around the entire method, so programming errors still surface clearly during development.
Testing Requirements
Unit tests using flutter_test with a mocked IRegistrationPreferencesStore: test getDefaults() returns null lastUsedActivityTypeId when store returns null, test getDefaults() returns the stored ID when store has a value, test getDefaults() returns fallback RegistrationDefaults when store throws, test saveLastUsedActivityType() calls store.write() with correct key and value. Verify DateTime.now() is used for date (use a clock abstraction or check the date is today's date). Use mockito or mocktail to mock IRegistrationPreferencesStore. Target 100% branch coverage.
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.