import {
  isCoarsePointer,
  isLowPowerDevice,
  isMobileViewport,
  isSaveData,
  MOBILE_QUERY,
} from "./device";

const originalMatchMedia = window.matchMedia;

function mockMedia(active: string[]) {
  window.matchMedia = jest.fn().mockImplementation((query: string) => ({
    matches: active.includes(query),
    media: query,
    addEventListener() {},
    removeEventListener() {},
  }));
}

function mockNavigator(values: Record<string, unknown>) {
  for (const [key, value] of Object.entries(values))
    Object.defineProperty(navigator, key, { configurable: true, value });
}

beforeEach(() => {
  mockMedia([]);
  mockNavigator({
    hardwareConcurrency: 8,
    deviceMemory: undefined,
    connection: undefined,
  });
});

afterEach(() => {
  window.matchMedia = originalMatchMedia;
});

describe("device hints", () => {
  it("treats a capable desktop as full power", () => {
    expect(isLowPowerDevice()).toBe(false);
    expect(isCoarsePointer()).toBe(false);
    expect(isSaveData()).toBe(false);
    expect(isMobileViewport()).toBe(false);
  });

  it("reads the phone breakpoint from the shared query", () => {
    mockMedia([MOBILE_QUERY]);
    expect(isMobileViewport()).toBe(true);
    expect(MOBILE_QUERY).toBe("(max-width: 767px)");
  });

  it.each([
    ["a touch pointer", () => mockMedia(["(pointer: coarse)"])],
    ["reduced motion", () => mockMedia(["(prefers-reduced-motion: reduce)"])],
    ["the data saver", () => mockNavigator({ connection: { saveData: true } })],
    ["four cores", () => mockNavigator({ hardwareConcurrency: 4 })],
    ["two cores", () => mockNavigator({ hardwareConcurrency: 2 })],
    ["4 GB of memory", () => mockNavigator({ deviceMemory: 4 })],
    ["2 GB of memory", () => mockNavigator({ deviceMemory: 2 })],
  ])("is low power with %s", (_label, arrange) => {
    arrange();
    expect(isLowPowerDevice()).toBe(true);
  });

  it("does not penalize a browser that hides the hardware hints", () => {
    mockNavigator({ hardwareConcurrency: undefined, deviceMemory: undefined });
    expect(isLowPowerDevice()).toBe(false);
  });

  it("keeps 8 GB and 6 cores on the full path", () => {
    mockNavigator({ hardwareConcurrency: 6, deviceMemory: 8 });
    expect(isLowPowerDevice()).toBe(false);
  });
});