using System.Text.Json;
using System.Text.Json.Serialization;
using BigRegister.Api.Contracts;
using BigRegister.Api.Data;
using BigRegister.Domain.Authorization;
using BigRegister.Domain.Diplomas;
using BigRegister.Domain.Documents;
using BigRegister.Domain.Intake;
using BigRegister.Domain.Letters;
using BigRegister.Domain.Registrations;
using BigRegister.Domain.Submissions;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Console;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen(c =>
    c.SwaggerDoc("v1", new() { Title = "BIG-register BFF", Version = "v1" }));
builder.Services.AddProblemDetails();
builder.Services.ConfigureHttpJsonOptions(o =>
{
  o.SerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
  o.SerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
});
// So the correlation-id scope pushed by the middleware below actually shows up in
// the console, not just in memory for a formatter that never renders it.
builder.Logging.AddSimpleConsole(o => o.IncludeScopes = true);

const string SpaCors = "spa";
builder.Services.AddCors(o => o.AddPolicy(SpaCors, p =>
    p.WithOrigins("http://localhost:4200").AllowAnyHeader().AllowAnyMethod()));

// WP-22: the three stores (Applications/Documents/Briefs — Data/*.cs) are static
// classes that open their own short-lived AppDbContext per call (see Db.Create),
// not DI-injected, so there's no builder.Services.AddDbContext here. Configuring
// the connection string still goes through IConfiguration so tests/deployments can
// override it (ConnectionStrings:AppDb) without touching this file.
Db.ConnectionString = builder.Configuration.GetConnectionString("AppDb") ?? Db.ConnectionString;

var app = builder.Build();

// Migrate on every startup, seed nothing (WP-22): unlike SeedData's read-only
// reference fixtures (registration/diplomas/notes — untouched by this WP, still
// static in-memory), Applications/Documents/Briefs never had seed data — they
// started empty and accumulated through normal use before this WP too. A fresh
// SQLite file just starts empty again, same as the old in-memory dictionaries did.
using (var db = Db.Create())
  db.Database.Migrate();

// Every request gets a correlation id (client-supplied X-Correlation-Id if present,
// else generated), pushed into the logging scope for every log line the request
// produces (not just the Submit helper's) and echoed back as a response header for
// support/debugging correlation. Runs first so nothing downstream logs without it.
app.Use(async (ctx, next) =>
{
  var cid = ctx.Request.Headers.TryGetValue("X-Correlation-Id", out var v) && !string.IsNullOrEmpty(v)
      ? v.ToString()
      : Guid.NewGuid().ToString();
  ctx.Items["CorrelationId"] = cid;
  ctx.Response.Headers["X-Correlation-Id"] = cid;
  using (app.Logger.BeginScope("CorrelationId:{CorrelationId}", cid))
    await next(ctx);
});

app.UseSwagger();
app.UseSwaggerUI();
app.UseCors(SpaCors);

// Liveness/readiness for orchestrators (k8s probes, load balancers). No data, no PII.
app.MapGet("/health", () => Results.Ok(new { status = "ok" }));
app.MapGet("/health/ready", () => Results.Ok(new { status = "ready" }));

// Versioned prefix: additive changes (new fields) stay on v1 — the generated client
// + FE parse* boundary absorb them; a breaking change introduces /api/v2 alongside.
var api = app.MapGroup("/api/v1");

// --- GET: screen-shaped reads. Decisions are computed here, never on the client. ---

api.MapGet("/dashboard-view", () =>
{
  var reg = SeedData.Registration;
  var (eligible, reason) = HerregistratieRule.Evaluate(reg, DateOnly.FromDateTime(DateTime.Today));
  return new DashboardViewDto(reg.ToDto(), SeedData.Person.ToDto(),
      new HerregistratieDecisionsDto(eligible, reason));
});

api.MapGet("/notes", () =>
    SeedData.Notes.Select(n => new AantekeningDto(n.Type, n.Omschrijving, n.Datum)).ToList());

// BRP "no address" fallback would be `new BrpAddressDto(false, null)` — the seeded
// citizen has one.
api.MapGet("/brp/address", () => new BrpAddressDto(true, SeedData.BrpAddress.ToDto()));

api.MapGet("/duo/diplomas", () => new DuoLookupDto(
    SeedData.Diplomas.Select(d => d.ToDto()).ToList(),
    new ManualDiplomaPolicyDto(
        DiplomaRules.ManualProfessions(),
        DiplomaRules.ManualQuestions().Select(q => q.ToDto()).ToList())));

api.MapGet("/intake/policy", () => new IntakePolicyDto(IntakePolicy.ScholingThreshold));

// --- POST: submits. The server is the authority; it re-validates and decides. ---

api.MapPost("/registrations", (RegistratieRequest req, HttpContext ctx) =>
    Submit(ctx, "registratie", SubmissionRules.RejectRegistratie(req.DiplomaHerkomst), req.Documents))
.Produces<ReferentieResponse>()
.ProducesProblem(StatusCodes.Status422UnprocessableEntity);

api.MapPost("/herregistraties", (HerregistratieRequest req, HttpContext ctx) =>
    Submit(ctx, "herregistratie", SubmissionRules.RejectZeroUren(req.Uren), req.Documents))
.Produces<ReferentieResponse>()
.ProducesProblem(StatusCodes.Status422UnprocessableEntity);

api.MapPost("/intakes", (IntakeRequest req, HttpContext ctx) =>
    Submit(ctx, "intake", SubmissionRules.RejectZeroUren(req.Uren)))
.Produces<ReferentieResponse>()
.ProducesProblem(StatusCodes.Status422UnprocessableEntity);

api.MapPost("/change-requests", (ChangeRequestRequest req, HttpContext ctx) =>
    Submit(ctx, "adreswijziging", SubmissionRules.RejectChangeRequest(req.Straat, req.Postcode)))
.Produces<ReferentieResponse>()
.ProducesProblem(StatusCodes.Status422UnprocessableEntity);

// --- Document upload ---

// Server-owned category config per wizard. The FE renders these; it never hardcodes.
api.MapGet("/uploads/categories", (string wizardId, string? diplomaHerkomst, string? taalvaardigheid) =>
    new UploadCategoriesDto(DocumentRules.CategoriesFor(wizardId, diplomaHerkomst, taalvaardigheid).Select(c => c.ToDto()).ToList()));

// Multipart upload. Hand-written on the FE (XHR for progress), so it is excluded
// from the OpenAPI doc to keep the NSwag-generated client JSON-only. Validates type
// and size authoritatively; stores metadata only (no file bytes / PII held).
api.MapPost("/uploads", async (HttpRequest request) =>
{
  if (!request.HasFormContentType) return Results.Problem(detail: "Verwacht multipart/form-data.", statusCode: 400);
  var form = await request.ReadFormAsync();
  var file = form.Files.GetFile("file");
  string categoryId = form["categoryId"].ToString(), localId = form["localId"].ToString(), wizardId = form["wizardId"].ToString();
  if (file is null || categoryId == "" || localId == "" || wizardId == "")
    return Results.Problem(detail: "Onvolledige upload.", statusCode: 400);

  var category = DocumentRules.Find(wizardId, categoryId);
  var reject = DocumentRules.RejectUpload(category, file.ContentType, file.Length);
  if (reject is not null) return Results.Problem(detail: reject, statusCode: 400);

  using var ms = new MemoryStream();
  await file.CopyToAsync(ms);
  var doc = DocumentStore.Add(localId, categoryId, wizardId, file.FileName, file.ContentType, ms.ToArray(), DocumentStore.DemoOwner);
  return Results.Created($"/api/v1/uploads/{doc.DocumentId}", new UploadResponse(doc.DocumentId, localId));
})
.ExcludeFromDescription();

// Serve stored bytes so a re-opened wizard can preview/download an upload. Inline
// for pdf/image (browser renders it), attachment otherwise (download).
api.MapGet("/uploads/{documentId}/content", (string documentId) =>
{
  var doc = DocumentStore.Get(documentId);
  if (doc is null) return Results.NotFound();
  var inline = doc.ContentType == "application/pdf" || doc.ContentType.StartsWith("image/");
  return Results.File(doc.Content, doc.ContentType, fileDownloadName: inline ? null : doc.FileName);
})
.Produces(StatusCodes.Status200OK)
.Produces(StatusCodes.Status404NotFound);

// Poll-on-return: which of these client localIds have arrived at the BFF.
api.MapGet("/uploads/status", (string? localIds) =>
{
  var ids = (localIds ?? "").Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
  var found = DocumentStore.ByLocalIds(ids).ToDictionary(d => d.LocalId);
  var results = ids.Select(id => found.TryGetValue(id, out var d)
      ? new UploadStatusItemDto(id, "complete", d.DocumentId)
      : new UploadStatusItemDto(id, "unknown", null)).ToList();
  return new UploadStatusDto(results);
});

// User delete: owner-scoped; 409 once linked to a finalised submission.
api.MapDelete("/uploads/{documentId}", (string documentId) =>
    DocumentStore.DeleteOwned(documentId, DocumentStore.DemoOwner) switch
    {
      DocumentStore.DeleteResult.Ok => Results.NoContent(),
      DocumentStore.DeleteResult.Linked => Results.Problem(
          detail: "Dit document is al gekoppeld aan een ingediende aanvraag en kan niet meer worden verwijderd.",
          statusCode: StatusCodes.Status409Conflict),
      _ => Results.NotFound(),
    })
.Produces(StatusCodes.Status204NoContent)
.ProducesProblem(StatusCodes.Status409Conflict)
.Produces(StatusCodes.Status404NotFound);

// Admin delete (seam): a real system requires an admin role; here an X-Admin header
// stands in. Bypasses ownership, unlinks, and flags the submission for review.
api.MapDelete("/admin/uploads/{documentId}", (string documentId, HttpContext ctx) =>
    !IsAdmin(ctx) ? Results.StatusCode(StatusCodes.Status403Forbidden)
        : DocumentStore.AdminDelete(documentId, "admin") ? Results.NoContent() : Results.NotFound())
.Produces(StatusCodes.Status204NoContent)
.Produces(StatusCodes.Status403Forbidden)
.Produces(StatusCodes.Status404NotFound);

// --- Applications (aanvragen): the system of record the dashboard reads. ---

api.MapGet("/applications", () =>
{
  var now = DateTimeOffset.UtcNow;
  return ApplicationStore.List(DocumentStore.DemoOwner)
      .OrderByDescending(a => a.UpdatedAt)
      .Select(a => a.ToSummaryDto(now)).ToList();
});

api.MapGet("/applications/{id}", (string id) =>
    ApplicationStore.Get(id, DocumentStore.DemoOwner) is { } a
        ? Results.Ok(a.ToDetailDto(DateTimeOffset.UtcNow))
        : Results.NotFound())
.Produces<ApplicationDetailDto>()
.Produces(StatusCodes.Status404NotFound);

api.MapPost("/applications", (CreateApplicationRequest req) =>
{
  var a = ApplicationStore.Create(req.Type, DocumentStore.DemoOwner);
  return Results.Created($"/api/v1/applications/{a.Id}", a.ToDetailDto(DateTimeOffset.UtcNow));
})
.Produces<ApplicationDetailDto>(StatusCodes.Status201Created);

// Draft sync per step — idempotent; keep it debounced on the client (it is chatty).
api.MapPut("/applications/{id}", (string id, DraftSyncRequest req) =>
    ApplicationStore.SyncDraft(id, DocumentStore.DemoOwner, req.Draft, req.StepIndex, req.StepCount, req.DocumentIds)
        ? Results.NoContent() : Results.NotFound())
.Produces(StatusCodes.Status204NoContent)
.Produces(StatusCodes.Status404NotFound);

// Cancel a Concept (cascades to its unlinked documents). Submitted aanvragen cannot
// be withdrawn (out of scope — no "intrekken").
api.MapDelete("/applications/{id}", (string id) =>
{
  var a = ApplicationStore.Get(id, DocumentStore.DemoOwner);
  if (a is null) return Results.NotFound();
  if (a.Submitted)
    return Results.Problem(detail: "Een ingediende aanvraag kan niet worden geannuleerd.", statusCode: StatusCodes.Status409Conflict);
  ApplicationStore.Delete(id, DocumentStore.DemoOwner);
  return Results.NoContent();
})
.Produces(StatusCodes.Status204NoContent)
.ProducesProblem(StatusCodes.Status409Conflict)
.Produces(StatusCodes.Status404NotFound);

// Submit runs the server-owned rules, sets autoApprovable, and transitions the
// aanvraag. handmatig no longer 422s (ADR-0002): it becomes a manual (pending) case.
api.MapPost("/applications/{id}/submit", (string id, SubmitApplicationRequest req, HttpContext ctx) =>
{
  var existing = ApplicationStore.Get(id, DocumentStore.DemoOwner);
  if (existing is null) return Results.NotFound();
  if (existing.Submitted)
    return Results.Problem(detail: "Aanvraag is al ingediend.", statusCode: StatusCodes.Status409Conflict);

  // Per wizard type: what rejects the submission (→ Afgewezen) and whether it auto-approves.
  (string? reject, bool autoApprovable) = existing.Type switch
  {
    "registratie" => (null, req.DiplomaHerkomst == "duo"),
    _ /* herregistratie | intake */ => (SubmissionRules.RejectZeroUren(req.Uren ?? 0), true),
  };

  var docs = req.Documents;
  if (docs is not null)
    DocumentStore.Link(docs.Where(d => d.Channel == "digital" && d.DocumentId is not null).Select(d => d.DocumentId!));
  var documentIds = docs?.Where(d => d.DocumentId is not null).Select(d => d.DocumentId!).ToList();

  var submitted = ApplicationStore.Submit(id, DocumentStore.DemoOwner, reject, autoApprovable, documentIds);
  if (submitted is null) return Results.Conflict();

  app.Logger.LogInformation(
      "aanvraag submit id={Id} type={Type} outcome={Outcome} auto={Auto} reference={Reference}",
      id, existing.Type, reject is null ? "accepted" : "rejected", autoApprovable, submitted.Referentie);
  return Results.Ok(new SubmitApplicationResponse(submitted.Referentie!, submitted.ToStatusDto(DateTimeOffset.UtcNow)));
})
.Produces<SubmitApplicationResponse>()
.ProducesProblem(StatusCodes.Status409Conflict)
.Produces(StatusCodes.Status404NotFound);

// PRD-0002 §6: coarse, role-derived capabilities for nav/menu-level checks (NOT
// tied to a specific brief's live status — see BriefDecisionsDto for that).
api.MapGet("/me", (HttpContext ctx) => new MeDto(Authz.RoleCapabilities(Authz.ResolvePrincipal(ctx))))
.Produces<MeDto>();

// --- Brief (letter composition). One demo brief per owner; the server owns the
// status machine + authorization (Authz, PRD-0002 phase P1). Principal is a
// dev-only stand-in via X-Role (mirrors the X-Admin seam and the FE ?role=
// toggle) — no real identities in this POC. ---

api.MapGet("/brief", (HttpContext ctx) =>
{
  var e = BriefStore.GetOrCreate(DocumentStore.DemoOwner);
  return ToView(ctx, e);
})
.Produces<BriefViewDto>();

api.MapPut("/brief", (SaveBriefRequest req, HttpContext ctx) =>
{
  var isDrafter = Authz.ResolvePrincipal(ctx).Role == PrincipalRole.Drafter;
  return BriefResult(ctx, BriefStore.Save(DocumentStore.DemoOwner, req.Sections, isDrafter), "Alleen de opsteller mag de brief bewerken.");
})
.Produces<BriefViewDto>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.ProducesProblem(StatusCodes.Status409Conflict);

api.MapPost("/brief/submit", (HttpContext ctx) =>
{
  var isDrafter = Authz.ResolvePrincipal(ctx).Role == PrincipalRole.Drafter;
  var r = BriefStore.Submit(DocumentStore.DemoOwner, isDrafter, Now());
  LogBrief("submit", r);
  return BriefResult(ctx, r, "Alleen de opsteller mag indienen.");
})
.WithName("briefSubmit") // distinct name so the generated client method isn't `submit2`
.Produces<BriefViewDto>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.ProducesProblem(StatusCodes.Status409Conflict);

api.MapPost("/brief/approve", (HttpContext ctx) =>
{
  var r = BriefStore.Approve(DocumentStore.DemoOwner, Authz.ResolvePrincipal(ctx), Now());
  LogBrief("approve", r);
  return BriefResult(ctx, r, "De beoordelaar mag niet de opsteller zijn.");
})
.Produces<BriefViewDto>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.ProducesProblem(StatusCodes.Status409Conflict);

api.MapPost("/brief/reject", (RejectBriefRequest req, HttpContext ctx) =>
{
  var r = BriefStore.Reject(DocumentStore.DemoOwner, Authz.ResolvePrincipal(ctx), req.Comments, Now());
  LogBrief("reject", r);
  return BriefResult(ctx, r, "De beoordelaar mag niet de opsteller zijn.");
})
.Produces<BriefViewDto>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.ProducesProblem(StatusCodes.Status409Conflict);

api.MapPost("/brief/send", (HttpContext ctx) =>
{
  // Send-time placeholder linting is FE-authoritative in this slice (no C# parity
  // port); the backend only guards the approved→sent transition (not role-gated
  // today — see Authz.CanActOn(Send, …), a mechanical dispatch step).
  var r = BriefStore.Send(DocumentStore.DemoOwner, Now());
  LogBrief("send", r);
  return BriefResult(ctx, r, "Versturen kan niet in deze status.");
})
.Produces<BriefViewDto>()
.ProducesProblem(StatusCodes.Status409Conflict);

api.MapPost("/brief/reset", (HttpContext ctx) =>
{
  // Demo "start over": recreate a fresh draft. No guards — showcase affordance only.
  var e = BriefStore.ResetAndCreate(DocumentStore.DemoOwner);
  return ToView(ctx, e);
})
.WithName("briefReset")
.Produces<BriefViewDto>();

// --- Organization templates (WP-23): the second template axis — appearance and
// identity per sub-organization. Admin-only (X-Role: admin, the same dev-stub seam
// as drafter/approver); the same Authz check gates every endpoint and feeds the
// `orgtemplate:edit` capability on /me, so emit and enforce cannot drift. ---

api.MapGet("/admin/org-templates", (HttpContext ctx) => OrgAdmin(ctx, () =>
    Results.Ok(OrgTemplateStore.List())))
.WithName("orgTemplates")
.Produces<List<SubOrgSummaryDto>>()
.ProducesProblem(StatusCodes.Status403Forbidden);

api.MapGet("/admin/org-template/{subOrgId}", (string subOrgId, HttpContext ctx) => OrgAdmin(ctx, () =>
    OrgTemplateStore.AdminView(subOrgId) is { } view ? Results.Ok(view) : Results.NotFound()))
.WithName("orgTemplateGET")
.Produces<OrgTemplateAdminViewDto>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.Produces(StatusCodes.Status404NotFound);

api.MapPut("/admin/org-template/{subOrgId}", (string subOrgId, SaveOrgTemplateRequest req, HttpContext ctx) => OrgAdmin(ctx, () =>
{
  var reject = OrgTemplateRules.RejectDraft(req.Draft);
  if (reject is not null) return Results.Problem(detail: reject, statusCode: StatusCodes.Status400BadRequest);
  return OrgTemplateStore.SaveDraft(subOrgId, req.Draft) is { } view ? Results.Ok(view) : Results.NotFound();
}))
.WithName("orgTemplatePUT")
.Produces<OrgTemplateAdminViewDto>()
.ProducesProblem(StatusCodes.Status400BadRequest)
.ProducesProblem(StatusCodes.Status403Forbidden)
.Produces(StatusCodes.Status404NotFound);

api.MapPost("/admin/org-template/{subOrgId}/publish", (string subOrgId, HttpContext ctx) => OrgAdmin(ctx, () =>
{
  var r = OrgTemplateStore.Publish(subOrgId, Now());
  if (r is not null)
    app.Logger.LogInformation("orgtemplate publish subOrg={SubOrg} version={Version} affected={Affected}",
        subOrgId, r.Version, r.AffectedUnsentBriefs);
  return r is not null ? Results.Ok(r) : Results.NotFound();
}))
.WithName("orgTemplatePublish")
.Produces<PublishOrgTemplateResponse>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.Produces(StatusCodes.Status404NotFound);

api.MapPost("/admin/org-template/{subOrgId}/rollback/{version:int}", (string subOrgId, int version, HttpContext ctx) => OrgAdmin(ctx, () =>
    OrgTemplateStore.Rollback(subOrgId, version) is { } view ? Results.Ok(view) : Results.NotFound()))
.WithName("orgTemplateRollback")
.Produces<OrgTemplateAdminViewDto>()
.ProducesProblem(StatusCodes.Status403Forbidden)
.Produces(StatusCodes.Status404NotFound);

app.Run();

static bool IsAdmin(HttpContext ctx) => ctx.Request.Headers["X-Admin"] == "true";

// One gate for every org-template endpoint — the enforce twin of the
// `orgtemplate:edit` capability RoleCapabilities emits (single Authz source).
static IResult OrgAdmin(HttpContext ctx, Func<IResult> action) =>
    Authz.CanManageOrgTemplates(Authz.ResolvePrincipal(ctx))
        ? action()
        : Results.Problem(detail: "Alleen een beheerder mag organisatiesjablonen beheren.",
            statusCode: StatusCodes.Status403Forbidden);

static string Now() => DateTimeOffset.UtcNow.ToString("o");

BriefViewDto ToView(HttpContext ctx, BriefEntity e) => new(
    e.ToDto(),
    BriefSeed.PassagesFor(e.Beroep),
    Authz.Decisions(Authz.ResolvePrincipal(ctx), e.Status.Tag, e.DrafterId),
    // Sent letters render with the version pinned at send; everything else follows
    // the sub-org's current published template (WP-23 immutability invariant).
    OrgTemplateStore.TemplateForBrief(e.SubOrgId, e.Status.Tag == "sent" ? e.SentOrgTemplateVersion : null));

// Emit (decision flags, via ToView) and enforce (Forbidden/Conflict below) both run
// through Authz — see BriefStore.Review and Authz.CanActOn — so they cannot drift.
IResult BriefResult(HttpContext ctx, (BriefStore.Outcome outcome, BriefEntity? entity) r, string forbiddenDetail) => r.outcome switch
{
  BriefStore.Outcome.Ok => Results.Ok(ToView(ctx, r.entity!)),
  BriefStore.Outcome.Forbidden => Results.Problem(detail: forbiddenDetail, statusCode: StatusCodes.Status403Forbidden),
  _ => Results.Problem(detail: "Ongeldige overgang voor de huidige status van de brief.", statusCode: StatusCodes.Status409Conflict),
};

void LogBrief(string action, (BriefStore.Outcome outcome, BriefEntity? entity) r) =>
    app.Logger.LogInformation("brief {Action} outcome={Outcome} status={Status}",
        action, r.outcome, r.entity?.Status.Tag ?? "-");

// Audit + outcome for a submit, with NO personal data: only kind, outcome,
// generated reference and the caller's correlation id (the observability seam — a
// real system ships this to structured logging / an audit store). A repeated
// Idempotency-Key short-circuits to the first call's result — see IdempotencyStore
// — so a retried submit dedupes instead of minting a second reference.
IResult Submit(HttpContext ctx, string kind, string? reject, IReadOnlyList<DocumentRefDto>? documents = null)
{
  var cid = ctx.Items.TryGetValue("CorrelationId", out var v) ? (string)v! : "none";
  var idemKey = ctx.Request.Headers.TryGetValue("Idempotency-Key", out var k) && !string.IsNullOrEmpty(k)
      ? k.ToString()
      : null;

  if (idemKey is not null && IdempotencyStore.TryGet(idemKey, out var cached))
  {
    app.Logger.LogInformation("submit kind={Kind} outcome=replayed correlationId={Cid}", kind, cid);
    return cached!;
  }

  IResult result;
  if (reject is not null)
  {
    app.Logger.LogInformation("submit kind={Kind} outcome=rejected correlationId={Cid}", kind, cid);
    result = Results.Problem(detail: reject, statusCode: StatusCodes.Status422UnprocessableEntity);
  }
  else
  {
    if (documents is not null)
    {
      // Link digital documents (blocks later user delete) and record post-delivery
      // intent so a caseworker knows to expect the physical document.
      DocumentStore.Link(documents.Where(d => d.Channel == "digital" && d.DocumentId is not null).Select(d => d.DocumentId!));
      foreach (var d in documents.Where(d => d.Channel == "post"))
        DocumentStore.Audit("post-delivery", d.DocumentId ?? "-", d.CategoryId, cid);
    }

    var reference = SubmissionRules.NewReference();
    app.Logger.LogInformation(
        "submit kind={Kind} outcome=accepted reference={Reference} correlationId={Cid} at={At:o}",
        kind, reference, cid, DateTimeOffset.UtcNow);
    result = Results.Ok(new ReferentieResponse(reference));
  }

  if (idemKey is not null) IdempotencyStore.Set(idemKey, result);
  return result;
}

// Exposed so the integration tests can spin up the app with WebApplicationFactory.
public partial class Program { }