butcem/src/shared/portfolio.test.ts

import { describe, expect, it } from "vitest";
import {
  formatBp,
  holdingSummary,
  periodPoints,
  periodReport,
  runMovements,
  sumReports,
  type DatedMovement,
  type MovementInput,
} from "./portfolio";

const buy = (quantity: number, amountMinor: number): MovementInput => ({
  kind: "buy",
  quantity,
  amountMinor,
});

describe("ağırlıklı ortalama maliyet", () => {
  it("örnek senaryo: 10 gr 25.000 TL'ye, her ay ekleme", () => {
    // 10 gr × 2.500, 2 gr × 2.600, 2 gr × 2.700 → 14 gr, 35.600 TL; ort. 2.542,857…
    const run = runMovements([buy(10_000, 25_000_00), buy(2_000, 5_200_00), buy(2_000, 5_400_00)]);
    expect(run.quantity).toBe(14_000);
    expect(run.costMinor).toBe(35_600_00);
    expect(run.investedMinor).toBe(35_600_00);
    const s = holdingSummary(run, 3_000_00);
    expect(s.avgCostMinor).toBe(2_542_86);
    expect(s.currentValueMinor).toBe(42_000_00);
    expect(s.unrealizedMinor).toBe(6_400_00);
    // 6.400 / 35.600 = %17,98
    expect(s.unrealizedBp).toBe(1798);
  });

  it("satış: ortalama maliyetle düşer, gerçekleşmiş kâr/zarar", () => {
    const run = runMovements([
      buy(10_000, 30_000_00),
      buy(10_000, 40_000_00),
      { kind: "sell", quantity: 5_000, amountMinor: 20_000_00 },
    ]);
    // ort. 3.500 → 5 gr maliyet 17.500; satış 20.000 → +2.500
    expect(run.steps[2]).toMatchObject({ costOutMinor: 17_500_00, realizedMinor: 2_500_00 });
    expect(run.quantity).toBe(15_000);
    expect(run.costMinor).toBe(52_500_00);
    expect(run.proceedsMinor).toBe(20_000_00);
    // Kalan ortalama değişmez.
    expect(holdingSummary(run, null).avgCostMinor).toBe(3_500_00);
  });

  it("hediye çıkışı K/Z yazmaz; gelen hediye yatırım sayılmaz; tamamı çıkınca maliyet sıfır", () => {
    const run = runMovements([
      buy(3_000, 9_000_00),
      { kind: "gift_in", quantity: 1_000, amountMinor: 3_300_00 },
      { kind: "gift_out", quantity: 2_000, amountMinor: 0 },
      { kind: "sell", quantity: 2_000, amountMinor: 7_000_00 },
    ]);
    expect(run.investedMinor).toBe(9_000_00);
    expect(run.giftInMinor).toBe(3_300_00);
    // ort. 3.075 → çıkış 6.150, kalan 6.150; satış tümü → K/Z 850
    expect(run.giftOutCostMinor).toBe(6_150_00);
    expect(run.realizedMinor).toBe(850_00);
    expect(run.quantity).toBe(0);
    expect(run.costMinor).toBe(0);
    const s = holdingSummary(run, 3_500_00);
    expect(s).toMatchObject({ avgCostMinor: null, currentValueMinor: 0, unrealizedBp: null });
  });

  it("eldekinden fazla çıkış işaretlenir", () => {
    const run = runMovements([
      buy(1_000, 100_00),
      { kind: "sell", quantity: 2_000, amountMinor: 1 },
    ]);
    expect(run.negativeAt).toBe(1);
    expect(runMovements([buy(1_000, 100_00)]).negativeAt).toBeNull();
  });

  it("oran biçimi", () => {
    expect(formatBp(1798)).toBe("+%17,98");
    expect(formatBp(-350)).toBe("−%3,5");
    expect(formatBp(0)).toBe("%0");
  });
});

describe("dönemsel rapor", () => {
  it("noktalar: başlangıç, ay sonları, bitiş", () => {
    expect(periodPoints("2026-05-06", "2026-08-15")).toEqual([
      "2026-05-06",
      "2026-05-31",
      "2026-06-30",
      "2026-07-31",
      "2026-08-15",
    ]);
    expect(periodPoints("2026-05-31", "2026-06-30")).toEqual(["2026-05-31", "2026-06-30"]);
  });

  // Örnek: 10 gr'ı 25.000'e aldım, her ay 1 gr ekledim; 6 ay sonra ne kazandım?
  const prices: Record<string, number> = {
    "2026-01-01": 2_500_00,
    "2026-02-01": 2_600_00,
    "2026-03-01": 2_700_00,
    "2026-07-01": 3_000_00,
  };
  const priceAt = (date: string) => {
    const keys = Object.keys(prices)
      .filter((k) => k <= date)
      .sort();
    return keys.length ? prices[keys.at(-1)!]! : null;
  };
  const ms: DatedMovement[] = [
    { kind: "buy", date: "2026-01-01", quantity: 10_000, amountMinor: 25_000_00 },
    { kind: "buy", date: "2026-02-01", quantity: 1_000, amountMinor: 2_600_00 },
    { kind: "buy", date: "2026-03-01", quantity: 1_000, amountMinor: 2_700_00 },
    { kind: "gift_out", date: "2026-07-01", quantity: 1_000, amountMinor: 0 },
  ];

  it("örnek senaryo: yatırılan, dönem sonu değer, kâr", () => {
    const r = periodReport(ms, priceAt, "2026-01-01", "2026-07-02");
    expect(r.startValueMinor).toBe(0);
    expect(r.investedMinor).toBe(30_300_00);
    // 11 gr × 3.000 = 33.000; çıkan 1 gr o günkü değeri 3.000
    expect(r.endValueMinor).toBe(33_000_00);
    expect(r.giftOutMinor).toBe(3_000_00);
    expect(r.profitMinor).toBe(5_700_00);
    expect(r.profitBp).toBe(1881);
    expect(r.points.map((p) => p.valueMinor)).toEqual([
      0, 25_000_00, 28_600_00, 32_400_00, 32_400_00, 32_400_00, 32_400_00, 33_000_00,
    ]);
  });

  it("başlangıçta eldeki değer dönem içi kârdan düşülür; fiyat yoksa null", () => {
    const r = periodReport(ms, priceAt, "2026-03-15", "2026-07-02");
    expect(r.startValueMinor).toBe(32_400_00);
    expect(r.investedMinor).toBe(0);
    expect(r.profitMinor).toBe(33_000_00 + 3_000_00 - 32_400_00);
    expect(periodReport(ms, () => null, "2026-01-01", "2026-07-02").profitMinor).toBeNull();
  });

  it("toplam", () => {
    const a = periodReport(ms, priceAt, "2026-01-01", "2026-07-02");
    const t = sumReports([a, a], "2026-01-01", "2026-07-02");
    expect(t.investedMinor).toBe(60_600_00);
    expect(t.profitMinor).toBe(11_400_00);
    expect(t.points.at(-1)!.valueMinor).toBe(66_000_00);
    expect(sumReports([], "2026-01-01", "2026-01-31").points).toHaveLength(2);
  });
});