/**
 * @file Tests for spendPace — the 7-day burn rate, month to date and the
 * month-end forecast built from the daily cost series.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
import { describe, expect, it } from "vitest";
import { spendPace } from "../burnRate";

describe("spendPace", () => {
  it("averages the last 7 days and carries the pace to month end", () => {
    const daily = [
      { date: "2026-09-28", cost: 70 }, // before the 7-day window (09-29..10-05)
      { date: "2026-09-30", cost: 7 }, // inside the window, last month
      { date: "2026-10-01", cost: 7 },
      { date: "2026-10-05", cost: 14 },
      { date: "2026-10-06", cost: 99 }, // after today: ignored
    ];
    const p = spendPace(daily, "2026-10-05");
    expect(p.perDay7).toBe(4); // (7 + 7 + 14) / 7
    expect(p.monthToDate).toBe(21);
    expect(p.forecastMonth).toBe(21 + 4 * 26); // 26 days left in October
  });
  it("is all zero with no spend", () => {
    expect(spendPace([], "2026-02-28")).toEqual({ perDay7: 0, monthToDate: 0, forecastMonth: 0 });
  });
});