feat(budget): aylık bütçe motoru, limitler ve ay sonu tahmini

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/shared/budget.test.ts

@@ -0,0 +1,139 @@
+import { describe, expect, it } from "vitest";
+import {
+  budgetPeriod,
+  computeBudget,
+  daysBetween,
+  forecast,
+  periodOfDate,
+  roundUpLimit,
+  shiftMonth,
+  statusOf,
+  type CategoryAmounts,
+} from "./budget";
+
+describe("bütçe dönemi", () => {
+  it("takvim ayı ve 15'inde başlayan ay", () => {
+    expect(budgetPeriod("2026-11")).toEqual({ from: "2026-11-01", to: "2026-11-30" });
+    expect(budgetPeriod("2026-12", 15)).toEqual({ from: "2026-12-15", to: "2027-01-14" });
+    expect(budgetPeriod("2027-01", 28)).toEqual({ from: "2027-01-28", to: "2027-02-27" });
+    expect(periodOfDate("2026-11-14", 15)).toBe("2026-10");
+    expect(periodOfDate("2026-11-15", 15)).toBe("2026-11");
+    expect(periodOfDate("2027-01-03", 15)).toBe("2026-12");
+    expect(periodOfDate("2026-11-30")).toBe("2026-11");
+    expect(shiftMonth("2026-12", 1)).toBe("2027-01");
+    expect(shiftMonth("2026-01", -1)).toBe("2025-12");
+    expect(daysBetween("2026-11-01", "2026-11-30")).toBe(30);
+    expect(daysBetween("2026-12-15", "2027-01-14")).toBe(31);
+  });
+
+  it("durum eşikleri %80 ve %100", () => {
+    expect(statusOf(79_99, 100_00)).toBe("ok");
+    expect(statusOf(80_00, 100_00)).toBe("warning");
+    expect(statusOf(100_00, 100_00)).toBe("over");
+    expect(statusOf(5, null)).toBe("none");
+    expect(statusOf(1, 0)).toBe("over");
+  });
+
+  it("ay sonu tahmini: sabit + planlı + değişken tempo", () => {
+    const a: CategoryAmounts = {
+      fixedMinor: 1_000_00,
+      variableMinor: 3_000_00,
+      plannedMinor: 500_00,
+    };
+    // 10/30 gün geçti: değişken 3.000 → 9.000
+    expect(forecast(a, 10, 30)).toBe(10_500_00);
+    expect(forecast(a, 30, 30)).toBe(4_500_00);
+    expect(forecast(a, 0, 30)).toBe(1_500_00);
+    expect(roundUpLimit(1_234_56)).toBe(1_300_00);
+    expect(roundUpLimit(1_200_00)).toBe(1_200_00);
+  });
+});
+
+describe("bütçe toplama", () => {
+  const categories = [
+    { id: "market", parentId: null, name: "Market", order: 1 },
+    { id: "faturalar", parentId: null, name: "Faturalar", order: 2 },
+    { id: "elektrik", parentId: "faturalar", name: "Elektrik", order: 1 },
+    { id: "su", parentId: "faturalar", name: "Su", order: 2 },
+    { id: "eglence", parentId: null, name: "Eğlence", order: 3 },
+    { id: "sinema", parentId: "eglence", name: "Sinema", order: 1 },
+    { id: "giyim", parentId: null, name: "Giyim", order: 4 },
+  ];
+  const amt = (variable: number, fixed = 0, planned = 0): CategoryAmounts => ({
+    fixedMinor: fixed,
+    variableMinor: variable,
+    plannedMinor: planned,
+  });
+
+  it("üst limit alt kategorileri kapsar; alt limit iki kez sayılmaz; bütçesiz harcama", () => {
+    const r = computeBudget({
+      categories,
+      limits: new Map([
+        ["market", 10_000_00],
+        ["faturalar", 3_000_00],
+        ["elektrik", 1_500_00],
+        ["sinema", 500_00],
+      ]),
+      amounts: new Map([
+        ["market", amt(8_500_00)],
+        ["elektrik", amt(0, 1_600_00)],
+        ["su", amt(0, 400_00, 300_00)],
+        ["faturalar", amt(100_00)],
+        ["sinema", amt(200_00)],
+        ["eglence", amt(300_00)],
+        ["giyim", amt(1_000_00)],
+      ]),
+      elapsedDays: 30,
+      totalDays: 30,
+    });
+    // Toplam limit: market + faturalar + sinema (elektrik faturaların içinde).
+    expect(r.totals.limitMinor).toBe(13_500_00);
+    expect(r.totals.actualMinor).toBe(12_100_00);
+    // Bütçesiz: eğlencenin kendi harcaması + giyim.
+    expect(r.totals.unbudgetedMinor).toBe(1_300_00);
+    const line = (id: string) => r.lines.find((l) => l.categoryId === id)!;
+    expect(line("faturalar")).toMatchObject({
+      actualMinor: 2_100_00,
+      plannedMinor: 300_00,
+      status: "ok",
+      ratioBp: 7000,
+    });
+    expect(line("elektrik")).toMatchObject({ status: "over", remainingMinor: -100_00 });
+    expect(line("market").status).toBe("warning");
+    expect(line("eglence")).toMatchObject({
+      limitMinor: null,
+      actualMinor: 500_00,
+      status: "none",
+    });
+    // Sıra: ağaç sırası, derinlik.
+    expect(r.lines.map((l) => `${l.depth}:${l.categoryId}`)).toEqual([
+      "0:market",
+      "0:faturalar",
+      "1:elektrik",
+      "1:su",
+      "0:eglence",
+      "1:sinema",
+      "0:giyim",
+    ]);
+  });
+
+  it("tahmin limiti aşıyor uyarısı; limit yoksa durum none", () => {
+    const r = computeBudget({
+      categories,
+      limits: new Map([["market", 10_000_00]]),
+      amounts: new Map([["market", amt(4_000_00)]]),
+      elapsedDays: 10,
+      totalDays: 30,
+    });
+    expect(r.totals).toMatchObject({ status: "ok", forecastMinor: 12_000_00, forecastOver: true });
+    const empty = computeBudget({
+      categories,
+      limits: new Map(),
+      amounts: new Map(),
+      elapsedDays: 1,
+      totalDays: 30,
+    });
+    expect(empty.totals.status).toBe("none");
+    expect(empty.lines).toHaveLength(0);
+  });
+});