import { afterEach, describe, expect, it, vi } from "vitest";
import {
  fetchUpcomingPublicEvents,
  googleCalendarUrl,
  icalUrl,
  selectUpcoming,
  toGoogleCalendar,
  toWebcal,
  webcalUrl,
} from "@/lib/public-calendar";
import type { ApiEvent } from "@/lib/types";

const now = new Date("2026-09-28T10:00:00Z");

const row = (eventId: number, start: string, end: string, name = `E${eventId}`): ApiEvent => ({
  eventId,
  calendarId: 1,
  uuid: `u${eventId}`,
  name,
  description: "",
  startDateTime: start,
  endDateTime: end,
  createdDate: null,
  location: "",
  url: "",
  wholeDay: 0,
  repeatFrequency: "",
});

afterEach(() => {
  vi.unstubAllGlobals();
});

describe("subscription links", () => {
  it("builds the iCal, webcal and Google links from the API URL", () => {
    expect(icalUrl("https://api.nachklang.art")).toBe("https://api.nachklang.art/calendar/events/public/ical");
    expect(webcalUrl("https://api.nachklang.art")).toBe("webcal://api.nachklang.art/calendar/events/public/ical");
    expect(webcalUrl("http://localhost:3000")).toBe("webcal://localhost:3000/calendar/events/public/ical");
    // The same link the Angular landing page hardcoded.
    expect(googleCalendarUrl("https://api.nachklang.art")).toBe(
      "https://calendar.google.com/calendar/r?cid=webcal%3A%2F%2Fapi.nachklang.art%2Fcalendar%2Fevents%2Fpublic%2Fical",
    );
  });
});

describe("links for a password-protected calendar", () => {
  it("keeps the password through the webcal and Google conversions", () => {
    const ical = "https://api.nachklang.art/calendar/events/choir/ical?password=a%26b";
    expect(toWebcal(ical)).toBe("webcal://api.nachklang.art/calendar/events/choir/ical?password=a%26b");
    // Encoded once more as a whole, so Google hands back exactly the URL above.
    const cid = new URL(toGoogleCalendar(ical)).searchParams.get("cid");
    expect(cid).toBe("webcal://api.nachklang.art/calendar/events/choir/ical?password=a%26b");
  });
});

describe("selectUpcoming", () => {
  it("keeps events not yet over, earliest first, up to the limit", () => {
    const rows = [
      row(1, "2026-11-01T18:00:00Z", "2026-11-01T20:00:00Z"),
      row(2, "2026-07-01T18:00:00Z", "2026-07-01T20:00:00Z"), // over
      row(3, "2026-09-28T06:00:00Z", "2026-09-28T07:00:00Z"), // earlier today: still listed
      row(4, "2026-10-01T18:00:00Z", "2026-10-01T20:00:00Z"),
    ];
    expect(selectUpcoming(rows, now, 2).map((e) => e.eventId)).toEqual([3, 4]);
  });
});

describe("fetchUpcomingPublicEvents", () => {
  it("returns null instead of throwing when the API is unreachable or unhappy", async () => {
    vi.stubGlobal("fetch", vi.fn().mockRejectedValue(new TypeError("fetch failed")));
    await expect(fetchUpcomingPublicEvents("https://api.test", now, 3)).resolves.toBeNull();
    vi.stubGlobal("fetch", vi.fn().mockResolvedValue(new Response("{}", { status: 500 })));
    await expect(fetchUpcomingPublicEvents("https://api.test", now, 3)).resolves.toBeNull();
  });

  it("parses what the public feed returns", async () => {
    const fetch = vi.fn().mockResolvedValue(
      new Response(JSON.stringify([row(1, "2026-11-01T18:00:00Z", "2026-11-01T20:00:00Z")]), { status: 200 }),
    );
    vi.stubGlobal("fetch", fetch);
    const events = await fetchUpcomingPublicEvents("https://api.test", now, 3);
    expect(events?.map((e) => e.eventId)).toEqual([1]);
    expect(fetch).toHaveBeenCalledWith("https://api.test/calendar/events/public/json", { next: { revalidate: 300 } });
  });
});