// lib/vat-cadence.server.ts
// SERVER-ONLY PocketBase lookup for company VAT cadences.
//
// Split out from `vat-cadence.ts` because that module must stay client-safe
// (the Returns workbench is a client component and needs the period maths),
// while `lib/pb.ts` carries `import "server-only"`.

import { fetchCollection, PBRecord } from "./pb";
import { CompanyCadence, toCompanyCadence } from "./vat-cadence";

/**
 * Load cadence for the named companies (or every VAT client when
 * `allActive`), in ONE PB round-trip.
 *
 * Returns `null` when PB is unavailable — callers treat that as
 * "cadence unknown" and fall back to the old unfiltered behaviour rather
 * than failing the run outright. Failing soft here matters: a PB outage
 * must not make it impossible to capture a return.
 */
export async function loadCompanyCadences(
  names: string[] | null,
  allActive: boolean
): Promise<{ byName: Map<string, CompanyCadence>; all: CompanyCadence[] } | null> {
  try {
    const wanted = new Set((names ?? []).map((n) => n.trim().toUpperCase()).filter(Boolean));
    let data: { items: PBRecord[] };
    if (allActive) {
      // VAT201 applies to VAT-registered entities — mirror the .py's gate.
      data = await fetchCollection<PBRecord>("ysterbaard_companies", {
        perPage: 500,
        filter: "is_client=true",
        fields: "id,enterprise_name,sars_vat_no,sars_vat_returns_period",
      });
    } else {
      if (wanted.size === 0) return { byName: new Map(), all: [] };
      const filter = [...wanted]
        .map((n) => `enterprise_name = "${n.replace(/"/g, '\\"')}"`)
        .join(" || ");
      data = await fetchCollection<PBRecord>("ysterbaard_companies", {
        perPage: 500,
        filter,
        fields: "id,enterprise_name,sars_vat_no,sars_vat_returns_period",
      });
    }

    const all: CompanyCadence[] = data.items
      .map((r) =>
        toCompanyCadence({
          id: (r.id as string) || "",
          enterprise_name: (r.enterprise_name as string) || "",
          sars_vat_no: (r.sars_vat_no as string) ?? "",
          sars_vat_returns_period: (r.sars_vat_returns_period as number | null) ?? null,
        })
      )
      // An explicit selection keeps clients with no VAT number so the caller
      // can report WHY each one was skipped ("no SARS VAT number") instead of
      // implying the record is missing. For --all-active the selection means
      // "every VAT client", so that filter does apply.
      .filter((c) => c.name && (allActive ? c.hasVatNo : true));

    const byName = new Map<string, CompanyCadence>();
    for (const c of all) byName.set(c.name.trim().toUpperCase(), c);
    return { byName, all };
  } catch (err) {
    console.error("[vat-cadence] failed to load company cadences:", err);
    return null;
  }
}