import {
  DEFAULT_PAYMENT_DRAIN_MINUTES,
  paymentDrainEndsAtIso,
  paymentDrainMs,
  payWindowLapsed,
} from "./booking-batch.constants";

/**
 * The drain tail is what keeps a pay window's LAST payment from being thrown
 * away: settlement is asynchronous (provider confirm → payment-api → outbox
 * relay), so a payment made in the window's final seconds lands after
 * `paymentDeadline`. Nothing may expire, no wagons may be resold and no window
 * cycle may conclude until the tail has passed.
 */
describe("payWindowLapsed — pay-window drain tail", () => {
  const deadline = new Date("2026-08-02T22:04:41Z");
  const at = (offsetMs: number) => deadline.getTime() + offsetMs;
  const MIN = 60_000;

  afterEach(() => {
    delete process.env.FREIGHT_PAYMENT_DRAIN_MINUTES;
  });

  it("is not lapsed before the deadline", () => {
    expect(payWindowLapsed(deadline, at(-1 * MIN))).toBe(false);
  });

  it("is not lapsed inside the drain tail", () => {
    // The reproduced finding: settled ~7 minutes late. With the default 5-minute
    // tail the booking is still live at 4 minutes.
    expect(payWindowLapsed(deadline, at(4 * MIN))).toBe(false);
    expect(payWindowLapsed(deadline, at(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN - 1))).toBe(
      false,
    );
  });

  it("is lapsed once the tail passes", () => {
    expect(payWindowLapsed(deadline, at(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN))).toBe(
      true,
    );
    expect(payWindowLapsed(deadline, at(7 * MIN))).toBe(true);
  });

  it("never lapses without a deadline — callers decide what unknown means", () => {
    expect(payWindowLapsed(null, at(60 * MIN))).toBe(false);
    expect(payWindowLapsed(undefined, at(60 * MIN))).toBe(false);
  });

  it("honours FREIGHT_PAYMENT_DRAIN_MINUTES", () => {
    process.env.FREIGHT_PAYMENT_DRAIN_MINUTES = "20";
    expect(paymentDrainMs()).toBe(20 * MIN);
    expect(payWindowLapsed(deadline, at(10 * MIN))).toBe(false);
    expect(payWindowLapsed(deadline, at(20 * MIN))).toBe(true);
  });

  it("allows an explicit zero drain (old deadline-is-the-line behaviour)", () => {
    process.env.FREIGHT_PAYMENT_DRAIN_MINUTES = "0";
    expect(paymentDrainMs()).toBe(0);
    expect(payWindowLapsed(deadline, at(0))).toBe(true);
  });

  it("falls back to the default on garbage or negative values", () => {
    for (const bad of ["", "abc", "-3"]) {
      process.env.FREIGHT_PAYMENT_DRAIN_MINUTES = bad;
      expect(paymentDrainMs()).toBe(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN);
    }
  });

  it("paymentDrainEndsAtIso reports deadline + drain, null/garbage-safe", () => {
    expect(paymentDrainEndsAtIso(deadline)).toBe(
      new Date(at(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN)).toISOString(),
    );
    expect(paymentDrainEndsAtIso(deadline.toISOString())).toBe(
      new Date(at(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN)).toISOString(),
    );
    expect(paymentDrainEndsAtIso(null)).toBeNull();
    expect(paymentDrainEndsAtIso(undefined)).toBeNull();
    expect(paymentDrainEndsAtIso("not-a-date")).toBeNull();
  });
});