import { describe, expect, it } from "vitest";
import {
  addDays,
  addMonths,
  describeRecurrence,
  isFinished,
  listOccurrences,
  occurrenceDate,
  type Recurrence,
} from "./recurrence";

const rule = (over: Partial<Recurrence>): Recurrence => ({
  frequency: "monthly",
  interval: 1,
  monthlyMode: "day",
  startDate: "2026-01-31",
  endDate: null,
  count: null,
  ...over,
});

describe("tarih aritmetiği", () => {
  it("gün ve ay ekleme, ay sonu taşması", () => {
    expect(addDays("2026-12-30", 3)).toBe("2027-01-02");
    expect(addDays("2028-03-01", -1)).toBe("2028-02-29");
    expect(addMonths("2026-01-31", 1)).toBe("2026-02-28");
    expect(addMonths("2026-01-31", 1, 31)).toBe("2026-02-28");
    expect(addMonths("2026-11-15", 3)).toBe("2027-02-15");
    expect(addMonths("2026-04-10", 0, "last")).toBe("2026-04-30");
  });
});

describe("occurrenceDate", () => {
  it("aylık: başlangıç günü korunur, ayda yoksa son gün", () => {
    const r = rule({});
    expect([0, 1, 2, 3].map((i) => occurrenceDate(r, i))).toEqual([
      "2026-01-31",
      "2026-02-28",
      "2026-03-31",
      "2026-04-30",
    ]);
  });

  it("aylık son gün modu (artık yıl dahil)", () => {
    const r = rule({ monthlyMode: "last", startDate: "2028-01-10" });
    expect([0, 1, 2].map((i) => occurrenceDate(r, i))).toEqual([
      "2028-01-31",
      "2028-02-29",
      "2028-03-31",
    ]);
  });

  it("günlük, haftalık (aralıkla), yıllık (29 Şubat)", () => {
    expect(
      occurrenceDate(rule({ frequency: "daily", interval: 3, startDate: "2026-11-30" }), 1),
    ).toBe("2026-12-03");
    expect(
      occurrenceDate(rule({ frequency: "weekly", interval: 2, startDate: "2026-11-02" }), 2),
    ).toBe("2026-11-30");
    const y = rule({ frequency: "yearly", startDate: "2028-02-29" });
    expect([1, 4].map((i) => occurrenceDate(y, i))).toEqual(["2029-02-28", "2032-02-29"]);
  });
});

describe("listOccurrences", () => {
  it("tekrar sayısı, bitiş tarihi ve ufuk sınırları", () => {
    const r = rule({ startDate: "2026-01-05", count: 3 });
    expect(listOccurrences(r, "2030-01-01").map((o) => o.date)).toEqual([
      "2026-01-05",
      "2026-02-05",
      "2026-03-05",
    ]);
    expect(isFinished(r, 3)).toBe(true);
    const e = rule({ startDate: "2026-01-05", endDate: "2026-02-10" });
    expect(listOccurrences(e, "2030-01-01")).toHaveLength(2);
    const h = rule({ startDate: "2026-01-05" });
    expect(listOccurrences(h, "2026-04-05").map((o) => o.index)).toEqual([0, 1, 2, 3]);
    expect(listOccurrences(h, "2026-04-05", 2).map((o) => o.index)).toEqual([2, 3]);
    expect(isFinished(h, 100)).toBe(false);
  });
});

describe("describeRecurrence", () => {
  it("Türkçe açıklama", () => {
    expect(describeRecurrence(rule({ startDate: "2026-11-03" }))).toBe("Her ay 3. gün");
    expect(describeRecurrence(rule({ monthlyMode: "last" }))).toBe("Her ayın son günü");
    expect(
      describeRecurrence(rule({ frequency: "weekly", interval: 2, startDate: "2026-11-02" })),
    ).toBe("2 haftada bir Pazartesi");
    expect(describeRecurrence(rule({ frequency: "yearly", startDate: "2026-03-15" }))).toBe(
      "Her yıl 15 Mart",
    );
    expect(describeRecurrence(rule({ frequency: "daily" }))).toBe("Her gün");
  });
});