import { describe, expect, it } from "vitest";

import { applyResumeRewind, normalizeResumeRewind } from "./audio-rewind";

describe("applyResumeRewind", () => {
  it("steps back by the rewind amount", () => {
    expect(applyResumeRewind(754, 5)).toBe(749);
    expect(applyResumeRewind(754, 10)).toBe(744);
  });

  it("clamps at the start of the book", () => {
    expect(applyResumeRewind(3, 5)).toBe(0);
    expect(applyResumeRewind(0, 10)).toBe(0);
  });

  it("treats rewind 0 (setting off) as exact resume", () => {
    expect(applyResumeRewind(754, 0)).toBe(754);
  });

  it("tolerates non-finite input", () => {
    expect(applyResumeRewind(Number.NaN, 5)).toBe(0);
    expect(applyResumeRewind(754, Number.NaN)).toBe(754);
    expect(applyResumeRewind(Number.POSITIVE_INFINITY, 5)).toBe(0);
  });
});

describe("normalizeResumeRewind", () => {
  it("passes the allow-listed amounts", () => {
    expect(normalizeResumeRewind(0)).toBe(0);
    expect(normalizeResumeRewind(5)).toBe(5);
    expect(normalizeResumeRewind(10)).toBe(10);
  });

  it("maps anything else to off", () => {
    expect(normalizeResumeRewind(7)).toBe(0);
    expect(normalizeResumeRewind(-5)).toBe(0);
    expect(normalizeResumeRewind("12")).toBe(0);
    expect(normalizeResumeRewind(undefined)).toBe(0);
    expect(normalizeResumeRewind(Number.NaN)).toBe(0);
  });
});