import { describe, expect, it } from "vitest";
import {
  SESSION_AUTO_CLOSE_MS,
  SESSION_WARN_THRESHOLD_MS,
  formatCountdown,
  sessionExpiryPhase,
  timeUntilExpiry,
} from "@/lib/session/countdown";

describe("timeUntilExpiry", () => {
  it("returns sessionExp - now", () => {
    expect(timeUntilExpiry(1_800_000_000, 1_700_000_000)).toBe(100_000_000);
  });

  it("defaults now to Date.now()", () => {
    const now = Date.now();
    const result = timeUntilExpiry(now + 5_000);
    expect(result).toBeGreaterThanOrEqual(4_900);
    expect(result).toBeLessThanOrEqual(5_000);
  });

  it("returns null when there is no known expiry", () => {
    expect(timeUntilExpiry(null)).toBeNull();
    expect(timeUntilExpiry(undefined)).toBeNull();
  });

  it("returns null for a non-finite expiry", () => {
    expect(timeUntilExpiry(Number.NaN)).toBeNull();
    expect(timeUntilExpiry(Number.POSITIVE_INFINITY)).toBeNull();
  });

  it("allows a negative remaining time (already expired)", () => {
    expect(timeUntilExpiry(100, 200)).toBe(-100);
  });
});

describe("sessionExpiryPhase", () => {
  const warn = SESSION_WARN_THRESHOLD_MS; // 15 min
  const close = SESSION_AUTO_CLOSE_MS; // 30s

  it("returns idle when remaining exceeds the warn window", () => {
    expect(sessionExpiryPhase(warn + 1)).toBe("idle");
    expect(sessionExpiryPhase(null)).toBe("idle");
  });

  it("returns warn inside the window (close < remaining <= warn)", () => {
    expect(sessionExpiryPhase(warn)).toBe("warn");
    expect(sessionExpiryPhase(close + 1)).toBe("warn");
    expect(sessionExpiryPhase(warn / 2)).toBe("warn");
  });

  it("returns close at or below the close threshold", () => {
    expect(sessionExpiryPhase(close)).toBe("close");
    expect(sessionExpiryPhase(0)).toBe("close");
    expect(sessionExpiryPhase(-1)).toBe("close");
  });

  it("honours custom thresholds", () => {
    expect(sessionExpiryPhase(10 * 60_000, 15 * 60_000, 5 * 60_000)).toBe("warn");
    expect(sessionExpiryPhase(3 * 60_000, 15 * 60_000, 5 * 60_000)).toBe("close");
  });
});

describe("formatCountdown", () => {
  it("formats under an hour as MM:SS", () => {
    expect(formatCountdown(0)).toBe("00:00");
    expect(formatCountdown(59)).toBe("00:59");
    expect(formatCountdown(60)).toBe("01:00");
    expect(formatCountdown(90)).toBe("01:30");
    expect(formatCountdown(599)).toBe("09:59");
  });

  it("formats hours as H:MM:SS", () => {
    expect(formatCountdown(3600)).toBe("1:00:00");
    expect(formatCountdown(3725)).toBe("1:02:05");
  });

  it("rounds up to the next whole second", () => {
    expect(formatCountdown(0.1)).toBe("00:01");
    expect(formatCountdown(59.4)).toBe("01:00");
  });

  it("never goes negative", () => {
    expect(formatCountdown(-5)).toBe("00:00");
  });

  it("handles non-finite input", () => {
    expect(formatCountdown(Number.NaN)).toBe("00:00");
    expect(formatCountdown(Number.POSITIVE_INFINITY)).toBe("00:00");
  });
});