Implement compensation eligibility rules engine
epic-quick-activity-registration-business-logic-task-005 — Implement the organisation-specific compensation eligibility logic inside ActivityRegistrationService. Rules must determine whether an activity type qualifies for HLF reimbursement based on the organisation's configuration retrieved from RegistrationPreferencesStore. The method isEligibleForCompensation(payload) must return a typed result with the eligibility flag and reason string for audit logging. Ineligible activities must still be submitted — eligibility only affects the reimbursement workflow downstream.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 1 - 540 tasks
Can start after Tier 0 completes
Implementation Notes
The eligibility engine must be organisation-agnostic at the code level — all organisation-specific rules live in data (RegistrationPreferencesStore), not in if/switch statements on organisation IDs. This is critical for scalability across NHF, Blindeforbundet, HLF, and future organisations. RegistrationPreferencesStore should be injected as a dependency into ActivityRegistrationService (constructor injection) for testability. CompensationEligibilityResult is purely informational — the downstream reimbursement workflow reads it; this service never initiates reimbursement.
The reason field should be an enum-backed string (e.g. CompensationIneligibilityReason enum) converted to a localisation key or English string, so it is consistent and auditable. Avoid free-form strings generated ad hoc.
Testing Requirements
Unit tests with flutter_test and mocked RegistrationPreferencesStore. Test cases: (1) organisation with eligible activity type returns isEligible: true with correct reason, (2) organisation with ineligible activity type returns isEligible: false, (3) organisation not found in preferences store returns isEligible: false with 'not found' reason, (4) method does not throw when ineligible, (5) cache behaviour — call isEligibleForCompensation twice for the same org, verify RegistrationPreferencesStore.getConfig is called only once. Use mockito or mocktail consistent with the codebase's mocking library.
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.