import { describe, expect, it } from "vitest";
import { fromWallTime } from "@/lib/dates";
import { filterEvents, groupByMonth, matchesQuery, matchesRange, sortEvents } from "@/lib/filter";
import { makeEvent } from "@/lib/test-fixtures";

const now = new Date("2026-09-27T10:00:00Z"); // 12:00 Berlin

describe("matchesRange", () => {
  it("keeps an event that ended earlier today in 'future' until midnight", () => {
    const earlierToday = makeEvent({
      start: fromWallTime("2026-09-27", "08:00"),
      end: fromWallTime("2026-09-27", "09:00"),
    });
    expect(matchesRange(earlierToday, "future", now)).toBe(true);
    expect(matchesRange(earlierToday, "past", now)).toBe(false);
  });

  it("puts yesterday's event in 'past'", () => {
    const yesterday = makeEvent({ start: fromWallTime("2026-09-26", "19:00"), end: fromWallTime("2026-09-26", "21:00") });
    expect(matchesRange(yesterday, "past", now)).toBe(true);
    expect(matchesRange(yesterday, "future", now)).toBe(false);
  });

  it("treats any repeating event as current, whatever its calendar", () => {
    const old = { start: fromWallTime("1990-01-01", "00:00"), end: fromWallTime("1990-01-01", "23:59") };
    const birthday = makeEvent({ ...old, calendarId: 5, repeatFrequency: "YEARLY" });
    const weeklyRehearsal = makeEvent({ ...old, calendarId: 4, repeatFrequency: "WEEKLY" });
    for (const e of [birthday, weeklyRehearsal]) {
      expect(matchesRange(e, "future", now)).toBe(true);
      expect(matchesRange(e, "past", now)).toBe(false);
      expect(matchesRange(e, "all", now)).toBe(true);
    }
  });

  it("no longer exempts a non-repeating event just for being in Birthdays", () => {
    const oneOff = makeEvent({ calendarId: 5, start: fromWallTime("2020-01-01", "00:00"), end: fromWallTime("2020-01-01", "23:59") });
    expect(matchesRange(oneOff, "future", now)).toBe(false);
  });
});

describe("matchesQuery", () => {
  const event = makeEvent({ name: "Probe Weihnachtskonzert", location: "Gemeindehaus Süd" });

  it("matches title and location, case-insensitively, all words", () => {
    expect(matchesQuery(event, "")).toBe(true);
    expect(matchesQuery(event, "weihnacht")).toBe(true);
    expect(matchesQuery(event, "PROBE süd")).toBe(true);
    expect(matchesQuery(event, "probe nord")).toBe(false);
  });
});

describe("filterEvents", () => {
  it("combines calendar, range and search", () => {
    const events = [
      makeEvent({ eventId: 1, calendarId: 1, name: "Konzert" }),
      makeEvent({ eventId: 2, calendarId: 2, name: "Konzert" }),
      makeEvent({ eventId: 3, calendarId: 1, name: "Probe" }),
    ];
    const result = filterEvents(events, { calendarIds: [1], range: "future", query: "konz" }, now);
    expect(result.map((e) => e.eventId)).toEqual([1]);
  });
});

describe("sortEvents", () => {
  const a = makeEvent({ eventId: 1, name: "B", start: fromWallTime("2026-10-02", "19:00") });
  const b = makeEvent({ eventId: 2, name: "A", start: fromWallTime("2026-10-02", "19:00") });
  const c = makeEvent({ eventId: 3, name: "C", start: fromWallTime("2026-10-01", "19:00") });

  it("orders by start and breaks ties by title", () => {
    expect(sortEvents([a, b, c], "start_asc", now).map((e) => e.eventId)).toEqual([3, 2, 1]);
    // Descending flips the dates only; equal starts still read A before B.
    expect(sortEvents([a, b, c], "start_desc", now).map((e) => e.eventId)).toEqual([2, 1, 3]);
  });

  it("does not mutate its input", () => {
    const input = [a, b, c];
    sortEvents(input, "start_asc", now);
    expect(input.map((e) => e.eventId)).toEqual([1, 2, 3]);
  });

  it("sorts a birthday by its next occurrence, not its year", () => {
    const birthday = makeEvent({ eventId: 9, repeatFrequency: "YEARLY", start: fromWallTime("1990-10-01", "12:00"), end: fromWallTime("1990-10-01", "23:59") });
    const concert = makeEvent({ eventId: 8, start: fromWallTime("2026-10-02", "19:00") });
    expect(sortEvents([concert, birthday], "start_asc", now).map((e) => e.eventId)).toEqual([9, 8]);
  });

  it("sorts by created date, missing ones first", () => {
    const x = makeEvent({ eventId: 1, created: new Date("2026-05-01T00:00:00Z") });
    const y = makeEvent({ eventId: 2, created: null });
    expect(sortEvents([x, y], "created_asc", now).map((e) => e.eventId)).toEqual([2, 1]);
  });
});

describe("groupByMonth", () => {
  it("groups consecutive events by Berlin month, labelled in German", () => {
    const events = [
      makeEvent({ eventId: 1, start: fromWallTime("2026-10-01", "00:30") }), // still 30 Sep in UTC
      makeEvent({ eventId: 2, start: fromWallTime("2026-10-20", "19:00") }),
      makeEvent({ eventId: 3, start: fromWallTime("2026-11-02", "19:00") }),
    ];
    const groups = groupByMonth(events, now);
    expect(groups.map((g) => [g.key, g.label, g.events.map((e) => e.eventId)])).toEqual([
      ["2026-10", "Oktober 2026", [1, 2]],
      ["2026-11", "November 2026", [3]],
    ]);
  });
});