Define period selector data contracts and event interface
epic-annual-impact-summary-core-services-task-001 — Design and implement the SummaryPeriod model, PeriodType enum (rolling-12-month, half-year, custom), and the event/state interface that the SummaryPeriodSelector widget will expose to the WrappedSummaryBLoC. This contract must be agreed before any BLoC or service development begins so all downstream components can depend on stable types.
Acceptance Criteria
Technical Requirements
Implementation Notes
Create this as a pure domain-layer file with zero framework dependencies. Use either plain Dart immutable classes with const constructors, or add freezed if the project already uses it — do not introduce freezed solely for this task. Place date arithmetic for rolling periods in static factory methods (SummaryPeriod.rollingTwelveMonths(), SummaryPeriod.lastSixMonths()) so callers never compute dates manually and future logic changes are centralised. The BLoC event/state definitions should live in a separate file (summary_period_bloc.dart) but import the domain models — keep the event thin (just carries a SummaryPeriod).
Document the contract decision with a brief // Contract: comment block at the top of each file so future developers understand this is a stable interface shared across multiple components.
Testing Requirements
Unit tests only (flutter_test). Three test groups: (1) PeriodType factory correctness — mock DateTime.now() to a fixed date and assert rollingTwelveMonths spans exactly 365 days back and lastSixMonths spans exactly 180 days back; (2) SummaryPeriod equality — two instances with identical fields must be equal and have identical hashCodes; (3) Edge cases — custom period with startDate == endDate is valid (single-day period), startDate > endDate throws ArgumentError. Target 100% line coverage for these three files as they are foundational contracts.
Activity records may contain duplicate entries (as evidenced by the duplicate-detection feature dependency) or proxy-registered activities that should be attributed differently. Including duplicates or mis-attributed records would produce inflated stats, undermining trust in the summary.
Mitigation & Contingency
Mitigation: Implement the aggregation query to join against the deduplication-reviewed-flag on activity records and filter out unresolved duplicates. Coordinate with the duplicate-detection feature team to confirm the authoritative flag field before implementing the RPC. Include a data-quality warning in the summary when unresolved duplicates are detected.
Contingency: If deduplication state is unreliable at release time, add a prominent disclaimer in the summary UI noting that figures reflect all registered activities and may include duplicates pending review. Track a follow-up task to re-aggregate after deduplication runs.
Each organisation wants to define their own milestone thresholds (e.g., NHF's counting model differs from HLF's certification model). Implementing configurable thresholds may expand scope significantly if the configuration UI is expected in this epic.
Mitigation & Contingency
Mitigation: Scope this epic strictly to the evaluation engine and a hardcoded default threshold set. Define the MilestoneDefinition interface with an organisation_id discriminator so per-org configs can be loaded from the database in a later sprint. Build the admin configuration UI as a separate follow-on task outside this epic.
Contingency: If stakeholders require per-org milestone configuration before launch, deliver a JSON-based configuration file per org as an interim solution, loaded from Supabase storage, until a full admin UI is built.
Android 13+ restricts access to media collections and requires READ_MEDIA_IMAGES permission for gallery saves, while older Android versions use WRITE_EXTERNAL_STORAGE. Handling both permission models correctly across the device matrix is error-prone.
Mitigation & Contingency
Mitigation: Use the permission_handler Flutter package with version-aware permission requests abstracted behind the summary-share-service interface. Write platform-specific unit tests for both Android API levels in the test harness. Test on a minimum of three Android versions (API 29, 32, 34) in CI.
Contingency: If gallery save is broken on specific Android versions at launch, disable the 'Save to gallery' option on affected API levels and surface only clipboard and system share sheet, which require no media permissions.