import { describe, expect, it } from "vitest";
import {
  BASE_VIEWPORT,
  MAX_VIEWPORT,
  renderViewportForBox,
} from "../src/game/rendering/viewport";

describe("adaptive native viewport", () => {
  it("keeps detached fixture canvases at the original resolution", () => {
    expect(renderViewportForBox(0, 0)).toEqual({
      ...BASE_VIEWPORT,
      pixelScale: 3,
    });
    expect(renderViewportForBox(Number.NaN, 500)).toEqual({
      ...BASE_VIEWPORT,
      pixelScale: 3,
    });
  });

  it("uses one integer scale on both axes and reveals additional world", () => {
    const phone = renderViewportForBox(390, 720);
    expect(phone).toEqual({ width: 195, height: 360, pixelScale: 2 });

    const desktop = renderViewportForBox(960, 648);
    expect(desktop).toEqual({ width: 320, height: 216, pixelScale: 3 });
    expect(desktop.width).toBeGreaterThan(BASE_VIEWPORT.width);
    expect(desktop.height).toBeGreaterThan(BASE_VIEWPORT.height);
    expect(desktop.width * desktop.pixelScale).toBe(960);
    expect(desktop.height * desktop.pixelScale).toBe(648);
  });

  it("rounds fractional boxes without materially changing their aspect", () => {
    const css = { width: 713.5, height: 481.25 };
    const viewport = renderViewportForBox(css.width, css.height);
    expect(
      Math.abs(viewport.width / viewport.height - css.width / css.height),
    ).toBeLessThan(0.005);
  });

  it.each([
    [304, 400],
    [844, 220],
    [1920, 600],
    [100_000, 100_000],
  ])(
    "preserves the aspect of a %d x %d box while bounding buffers",
    (width, height) => {
      const viewport = renderViewportForBox(width, height);
      expect(viewport.width).toBeLessThanOrEqual(MAX_VIEWPORT.width);
      expect(viewport.height).toBeLessThanOrEqual(MAX_VIEWPORT.height);
      expect(
        Math.abs(viewport.width / viewport.height - width / height),
      ).toBeLessThan(0.03);
    },
  );
});