Document report history UI components
epic-bufdir-report-history-ui-task-010 — Write developer documentation for the three report history UI components covering: widget API (constructor parameters, required vs optional), state management integration patterns (how to provide the BLoC/Riverpod notifier), expected data contracts from ReportHistoryService, accessibility implementation decisions, and usage examples showing how to embed ReportSummaryMetricsWidget inside ReportHistoryListItem. Include notes on session-scoped filter state behavior.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 6 - 158 tasks
Can start after Tier 5 completes
Implementation Notes
Prefer Dart doc comments (///) directly on public constructors and key methods over a separate markdown file — this keeps documentation close to the code and visible in IDEs. Use @param and @returns tags in Dart doc where applicable. For the usage example, write a minimal but complete example (wrap in a fake BlocProvider/ProviderScope so it is clear what the setup requires). Explain the session-scoped filter state clearly — e.g., 'Filters reset when the user navigates away from ReportHistoryScreen; they are stored in the BLoC/notifier and not persisted to the database.' This is important context for future developers who might expect persistence.
Document the accessibility choices made in task-007 so future maintainers understand why certain Semantics decisions were made and do not accidentally remove them.
Testing Requirements
No automated tests for documentation. Manual review: a developer not involved in the epic should be able to read the documentation and integrate ReportSummaryMetricsWidget into a new screen without asking questions. Documentation review checklist: all constructor params listed, integration example compiles, filter behavior explained, accessibility decisions explained.
The ReportSummaryMetricsWidget must display metrics as they were at time of submission, not recalculated from current data. If the metrics are not stored as a JSON snapshot in the history record at export time, the widget will either show wrong data or require a full re-aggregation on every list load.
Mitigation & Contingency
Mitigation: Ensure the Bufdir export pipeline (bufdir-report-export feature) writes a summary_metrics JSONB column in the history record at export time, containing total_activities, total_hours, and participants_reached. The UI widget reads only from this snapshot field — never from live aggregation queries.
Contingency: If snapshot data is missing for historical records (e.g., older exports before the column existed), display a 'Metrics not available for this report' placeholder in the widget rather than showing zeros or triggering a live aggregation that could return different figures.
Re-export can take several seconds (it runs the full generation pipeline). Without adequate progress feedback, coordinators may tap the button multiple times, triggering duplicate exports and duplicate history records.
Mitigation & Contingency
Mitigation: Disable the re-export button immediately on first tap and show an inline progress indicator on the list item. Guard against duplicate invocations at the service layer using an in-progress flag keyed by report ID. Display a loading state on the list item throughout the operation.
Contingency: If duplicate re-export records are created (e.g., due to a race condition), the history table will show multiple entries for the same original report — which is harmless but confusing. Add a deduplication UI hint ('Re-exported N times') and a backend guard that prevents more than one in-flight re-export for the same source record ID simultaneously.