import { tz } from "@date-fns/tz";
import { describe, expect, it } from "vite-plus/test";
import { calculateDatetime, formatDatetime } from "../src";

describe("formatDatetime", () => {
  it("returns formatted current date", () => {
    const result = formatDatetime({});
    expect(result).toMatch(/\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}/);
  });

  it("returns formatted specific date", () => {
    const result = formatDatetime({ date: "2025-07-13T12:34:56" });
    expect(result).toBe("2025-07-13 12:34:56");
  });

  it("returns formatted specific timestamp", () => {
    const result = formatDatetime({ date: "1752435296000", in: tz("America/Vancouver") });
    expect(result).toBe("2025-07-13 12:34:56");
  });

  it("returns formatted specific timestamp with decimals", () => {
    const result = formatDatetime({ date: "1752435296000.19", in: tz("America/Vancouver") });
    expect(result).toBe("2025-07-13 12:34:56");
  });

  it("returns formatted date with custom output", () => {
    const result = formatDatetime({ date: "2025-07-13T12:34:56", format: "dd/MM/yyyy" });
    expect(result).toBe("13/07/2025");
  });

  it("handles invalid date gracefully", () => {
    expect(() => formatDatetime({ date: "invalid-date" })).toThrow("Invalid date: invalid-date");
  });
});

describe("calculateDatetime", () => {
  it("returns ISO string for current date", () => {
    const result = calculateDatetime({});
    expect(result).toMatch(/\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}/);
  });

  it("returns ISO string for specific date", () => {
    const result = calculateDatetime({ date: "2025-07-13T12:34:56Z" });
    expect(result).toBe("2025-07-13T12:34:56.000Z");
  });

  it("applies calc operations", () => {
    const result = calculateDatetime({ date: "2025-07-13T12:00:00Z", expression: "+1d 2h" });
    expect(result).toBe("2025-07-14T14:00:00.000Z");
  });

  it("applies negative calc operations", () => {
    const result = calculateDatetime({ date: "2025-07-13T12:00:00Z", expression: "-1d -2h 1m" });
    expect(result).toBe("2025-07-12T10:01:00.000Z");
  });

  it("throws error for invalid unit", () => {
    expect(() => calculateDatetime({ date: "2025-07-13T12:00:00Z", expression: "+1x" })).toThrow(
      "Invalid date expression: +1x",
    );
  });
  it("throws error for invalid unit weird", () => {
    expect(() => calculateDatetime({ date: "2025-07-13T12:00:00Z", expression: "+1&#^%" })).toThrow(
      "Invalid date expression: +1&#^%",
    );
  });
  it("throws error for bad expression", () => {
    expect(() =>
      calculateDatetime({ date: "2025-07-13T12:00:00Z", expression: "bad expr" }),
    ).toThrow("Invalid date expression: bad");
  });
});