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

import {
  TOOLCRAFT_VIDEO_EXPORT_FRAMES_PER_SECOND,
  createToolcraftVideoFrameSchedule,
} from "./video-frame-schedule";

describe("createToolcraftVideoFrameSchedule", () => {
  it("creates exact timeline timestamps without duplicating the endpoint", () => {
    const schedule = createToolcraftVideoFrameSchedule(4.8);

    expect(TOOLCRAFT_VIDEO_EXPORT_FRAMES_PER_SECOND).toBe(30);
    expect(schedule).toHaveLength(144);
    expect(schedule[0]).toEqual({
      durationSeconds: 1 / 30,
      index: 0,
      timeSeconds: 0,
    });
    expect(schedule.at(-1)?.timeSeconds).toBe(143 / 30);
    expect(
      schedule.reduce(
        (end, frame) =>
          Math.max(end, frame.timeSeconds + frame.durationSeconds),
        0,
      ),
    ).toBeCloseTo(4.8, 10);
  });

  it("shortens only the final frame for a fractional duration", () => {
    const schedule = createToolcraftVideoFrameSchedule(1.01);

    expect(schedule).toHaveLength(31);
    expect(schedule.at(-1)).toEqual({
      durationSeconds: 1.01 - 1,
      index: 30,
      timeSeconds: 1,
    });
  });

  it.each([0.1, 0.3, 4.8, 4.9, 60])(
    "avoids a floating-point phantom frame for %s seconds",
    (durationSeconds) => {
      const schedule = createToolcraftVideoFrameSchedule(durationSeconds);

      expect(schedule).toHaveLength(Math.round(durationSeconds * 30));
      expect(schedule.at(-1)?.timeSeconds).toBeLessThan(durationSeconds);
    },
  );

  it.each([0, -1, Number.NaN, Number.POSITIVE_INFINITY])(
    "rejects invalid duration %s",
    (durationSeconds) => {
      expect(() => createToolcraftVideoFrameSchedule(durationSeconds)).toThrow(
        "positive finite duration",
      );
    },
  );
});