# WP-66 — Wire the decision into OpenZaak

Status: todo
Phase: 11 — Behandelportal

## Why

WP-65's decision currently only updates local state (`LocalZaakSource`). For the
behandelportal to actually function against a real register, the recorded decision needs
to also write a besluit/status transition to ZGW — extending the write capability that
already partially exists (`CreateStatusRequest`, `CreateRolRequest` in
`OpenZaakZaakSource.cs`) rather than building a new ZGW client from scratch.

## Read first

- `backend/src/BigRegister.Api/Zgw/OpenZaakZaakSource.cs` (existing write records)
- ZGW's Besluiten API (referenced in `openzaak-integration.md` if covered, or the ZGW
  standard docs) for besluit creation
- [WP-50](WP-50-openzaak-create-zaak.md) (the first ZGW write slice, for the pattern to
  follow)

## Decisions (pre-made, don't relitigate)

- Extend `IZaakSource`/`OpenZaakZaakSource` with a besluit/status-transition write,
  following the same pattern WP-50 established for create-zaak (a records + mapper
  addition, not a new abstraction).
- Gated by `Zgw:Enabled` like every other ZGW write — the behandelportal keeps working
  against `LocalZaakSource` when it's off.
- Best done after Phase 10's WP-60 (write-divergence resilience) lands, since this is
  exactly the second write pair that resilience work should already cover — but not
  strictly blocked on it if Phase 10 is still in progress (call out the residual risk
  explicitly if shipped first).

## Files

`Zgw/OpenZaakZaakSource.cs` (besluit/status write), `Data/IZaakSource.cs` (new write
method), tests.

## Steps

1. Add the besluit/status-transition write to `OpenZaakZaakSource`, mirroring WP-50's
   create-zaak pattern.
2. Wire WP-65's decision command to call it when `Zgw:Enabled=true`.
3. Integration test against the WP-54 harness (extend `OpenZaakIntegrationTests`).

## Acceptance criteria

- [ ] A recorded decision writes a real besluit/status transition to OpenZaak when
      `Zgw:Enabled=true`.
- [ ] Behandelportal still works unchanged against `LocalZaakSource` when
      `Zgw:Enabled=false`.
- [ ] `OpenZaakIntegrationTests` covers the new write.

## Verification

`cd backend && dotnet test --filter Category=Integration` against the (ideally
Phase-10-hardened) OpenZaak harness; manual smoke with `Zgw:Enabled=true`.

## Out of scope

Any further behandelportal screens beyond beoordeling.

## Risks

If Phase 10's WP-60 (write-divergence resilience) hasn't landed yet, this introduces a
second unprotected write pair — call this out explicitly if the two phases aren't
sequenced together in practice.

Depends on: WP-65. Benefits from (but doesn't strictly require) WP-60.