import { describe, it, expect } from "vitest";
import {
  DELIVERY_NOTE_LETTERHEAD_CODE,
  deliveryNoteLetterheadCode,
  letterheadForCompany,
} from "./letterhead";

/**
 * Locks down the contract that delivery-note PDFs always render under
 * the Westcott Group letterhead, regardless of which subsidiary the
 * customer belongs to. If a future change makes the rule
 * subsidiary-driven, this test is the guardrail that will fail first
 * and force the discussion.
 *
 * `letterheadForCompany` is intentionally kept narrow (ISHERWOOD / CNL
 * only) because that helper is also used by the quote / PO flows
 * which have different brand rules. Delivery notes don't.
 */

describe("deliveryNoteLetterheadCode", () => {
  it("is the Westcott Group letterhead", () => {
    expect(deliveryNoteLetterheadCode()).toBe("WESTSCOTT GROUP OF COMPANIES");
    expect(DELIVERY_NOTE_LETTERHEAD_CODE).toBe("WESTSCOTT GROUP OF COMPANIES");
  });

  it("returns the canonical code regardless of subsidiary name", () => {
    // Every subsidiary the Westcott Group owns should still render
    // under the Westcott letterhead. If anyone ever wires
    // `letterheadForCompany` into the delivery-note flow, this test
    // will catch it because `letterheadForCompany` returns CNL /
    // ISHERWOOD for these inputs.
    for (const subsidiary of [
      "CNL Fasteners (Pty) Ltd",
      "Isherwood Mining South Africa (Pty) Ltd",
      "Westcott Test Engineering (Pty) Ltd",
      "Merafong Crushers (Pty) Ltd.",
      "",
    ]) {
      const fromCompany = letterheadForCompany(subsidiary);
      const fromHelper = deliveryNoteLetterheadCode();
      // The helper is the source of truth for delivery notes — it
      // must never equal whatever `letterheadForCompany` returns for
      // a subsidiary name (CNL / ISHERWOOD are the only two it
      // could match; the helper must always be the Westcott code).
      expect(fromHelper).toBe("WESTSCOTT GROUP OF COMPANIES");
      expect(fromHelper).not.toBe(fromCompany ?? "");
    }
  });
});