import { Int64 } from "./Int64";

describe("Int64", () => {
  it("should hold integers greater than Number.MAX_SAFE_INTEGER without losing precision", () => {
    const bytes = Uint8Array.from([0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]);

    expect(new Int64(bytes).bytes).toEqual(bytes);
  });

  it("should allow the use of Int64s in arithmetic expressions", () => {
    const bytes = Uint8Array.from([0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10]);

    expect((new Int64(bytes) as any) + 4).toBe(20);
  });

  it("should allow the use of negative Int64s in arithmetic expressions", () => {
    const bytes = Uint8Array.from([0xff, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);

    expect((new Int64(bytes) as any) + 2 ** 52).toBe(0);
  });

  it("should stringify negative Int64s in base 10", () => {
    const bytes = Uint8Array.from([0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe2]);

    expect(String(new Int64(bytes))).toBe("-30");
  });

  it("should throw when given a buffer of the wrong byte length", () => {
    expect(() => new Int64(new Uint8Array(0))).toThrow();
  });

  it("should convert numbers into Int64 values", () => {
    expect(Int64.fromNumber(2147483647).bytes).toEqual(
      Uint8Array.from([0x00, 0x00, 0x00, 0x00, 0x7f, 0xff, 0xff, 0xff])
    );
  });

  it("should convert negative numbers into Int64 values", () => {
    expect(Int64.fromNumber(-2147483647).bytes).toEqual(
      Uint8Array.from([0xff, 0xff, 0xff, 0xff, 0x80, 0x00, 0x00, 0x01])
    );
  });

  it("should throw when a number larger than 2^63 -1 is provided", () => {
    // eslint-disable-next-line @typescript-eslint/no-loss-of-precision
    expect(() => Int64.fromNumber(9_323_372_036_854_775_807)).toThrow();
  });

  it("should throw when a number smaller than -1 * 2^63 is provided", () => {
    // eslint-disable-next-line @typescript-eslint/no-loss-of-precision
    expect(() => Int64.fromNumber(-9_323_372_036_854_775_807)).toThrow();
  });
});