import { describe, it, expect } from "vitest";
import { videoFitClass, fittedVideoSize } from "./videoFit";

describe("videoFitClass", () => {
  it("fills the container instead of capping at the source's intrinsic size", () => {
    const cls = videoFitClass();
    // max-w/max-h only shrink oversized media; a 480p source would stay a small
    // box in the middle of a large window.
    expect(cls).not.toContain("max-w-full");
    expect(cls).not.toContain("max-h-full");
    expect(cls).toContain("w-full");
    expect(cls).toContain("h-full");
  });

  it("preserves aspect ratio while fitting (letterbox, never crop)", () => {
    const cls = videoFitClass();
    expect(cls).toContain("object-contain");
    expect(cls).not.toContain("object-cover");
    expect(cls).not.toContain("object-fill");
  });
});

describe("fittedVideoSize", () => {
  it("scales a 480p source up to fill a larger window (the reported bug)", () => {
    // Exact 16:9 480p in a 1920x1080 window -> scales up to fill, rather than
    // staying a 854x480 box in the middle.
    const size = fittedVideoSize(853.33, 480, 1920, 1080);
    expect(size.width).toBeCloseTo(1920, 0);
    expect(size.height).toBeCloseTo(1080, 0);
  });

  it("fits to the constraining dimension when aspect ratios differ", () => {
    // 4:3 source in a 16:9 window -> height-constrained, pillarboxed.
    const size = fittedVideoSize(640, 480, 1920, 1080);
    expect(size.height).toBeCloseTo(1080, 0);
    expect(size.width).toBeCloseTo(1440, 0);
    expect(size.width).toBeLessThan(1920);
  });

  it("fits to width when the source is wider than the window", () => {
    // 21:9 source in a 16:9 window -> width-constrained, letterboxed.
    const size = fittedVideoSize(2560, 1080, 1920, 1080);
    expect(size.width).toBeCloseTo(1920, 0);
    expect(size.height).toBeCloseTo(810, 0);
    expect(size.height).toBeLessThan(1080);
  });

  it("shrinks oversized media to fit rather than overflowing", () => {
    const size = fittedVideoSize(3840, 2160, 1280, 720);
    expect(size.width).toBeCloseTo(1280, 0);
    expect(size.height).toBeCloseTo(720, 0);
  });

  it("returns a zero size for unknown intrinsic dimensions", () => {
    expect(fittedVideoSize(0, 0, 1920, 1080)).toEqual({ width: 0, height: 0 });
  });
});