Build Bufdir Category Mapper Integration in Serializer
epic-bufdir-report-export-core-backend-task-005 — Implement the Bufdir format serializer's category mapping layer that translates internal activity_type values to the canonical Bufdir activity category codes required by the submission format. Map org-specific terminology back to Bufdir's enumerated codes (e.g., individual counselling, group session, information event). The mapper must handle unmapped types gracefully by assigning an 'other' code and logging a warning rather than failing the serialization.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 1 - 540 tasks
Can start after Tier 0 completes
Implementation Notes
Define the mapping as a top-level Dart const: `const Map
Normalise the input with `.toLowerCase().trim()` before lookup. Avoid placing the mapping in the database — Bufdir codes are defined by an external standard and change infrequently; a code-level const avoids a round-trip and keeps the edge function self-contained. When Bufdir updates their category list, update the const and redeploy. Coordinate with the team to confirm all active activity_type values used in production before finalising the mapping table.
Testing Requirements
Unit tests using flutter_test (or dart:test in edge function context). Test matrix: (1) each of the ~6 known activity types maps to the correct Bufdir code, (2) three distinct unknown types all map to 'other' and populate warnings, (3) empty string and null inputs are handled without exceptions, (4) calling the mapper twice with identical input returns identical output (idempotency), (5) warning list is empty when all types are mapped. Target 100% branch coverage for the mapper function. No integration tests needed at this layer.
Supabase Edge Functions have a default execution timeout. For large national-scope exports aggregating tens of thousands of activities across 1,400 chapters, the edge function may time out before completing, leaving coordinators with a failed export and no partial output.
Mitigation & Contingency
Mitigation: Optimise the aggregation SQL using pre-materialised aggregation views or RPC functions that run inside the database rather than iterating records in Deno. Profile query execution time against realistic production data volumes early. Request an elevated timeout limit from Supabase if needed. Implement progress checkpointing so the export can be resumed from the last completed aggregation batch.
Contingency: For organisations exceeding a configurable threshold (e.g. >5,000 activities), switch to an asynchronous export pattern: the edge function writes a 'pending' audit record and enqueues the job; the client polls for completion and is notified via Supabase Realtime when the file is ready.
Server-side PDF generation in a Deno Edge Function environment restricts library choices. Many popular PDF libraries require Node.js APIs not available in Deno, or produce large bundle sizes that exceed edge function limits. Choosing the wrong library could block the entire PDF generation path.
Mitigation & Contingency
Mitigation: Spike PDF library selection as the first task of this epic, evaluating at least two Deno-compatible options (e.g. pdf-lib, jsPDF with Deno compatibility shim). Test bundle size and basic rendering before committing to an implementation. Document the chosen library's constraints.
Contingency: If no suitable Deno-native PDF library is found, generate a well-structured HTML report from the edge function and use a headless Chromium service (e.g. Browserless, Gotenberg) for HTML-to-PDF conversion, or temporarily ship CSV-only export while the PDF path is resolved.
Peer mentors affiliated with multiple chapters (a documented NHF scenario) must not be double-counted in participant totals. Incorrect deduplication logic would overreport participation figures to Bufdir, which could be discovered during audit and damage organisational credibility.
Mitigation & Contingency
Mitigation: Define and document the deduplication contract explicitly before coding: deduplication is per-person per-period, not per-activity. Build dedicated unit tests with fixtures containing the exact multi-chapter membership patterns described in NHF's documentation. Have a NHF representative validate test fixture outputs against known-good manual counts.
Contingency: If deduplication logic produces results that cannot be verified against manual counts before launch, surface a deduplication warning in the export preview listing the affected peer mentor IDs, and require explicit coordinator acknowledgement before finalising the export.