import { describe, it, expect } from "vitest";
import { minutesOutsideWindow, outOfWindowGap, type PlanTimeframes } from "./index.js";

// The "tariff bridge" gap for a subscriber scan outside their allowed window. UTC tz
// keeps the wall-clock arithmetic obvious in the tests. See wiki/entities/subscription.md.

// Night plan: window 20:00→08:00 (wraps midnight) on weekdays (Mon..Fri). Days not in the
// set (Sat/Sun) are unrestricted — no charge.
const night: PlanTimeframes = {
  days: [1, 2, 3, 4, 5], // Mon..Fri
  fromMin: 20 * 60,
  toMin: 8 * 60, // 1200 → 480
  graceMin: 0,
  tz: "UTC",
};

// 2026-06-22 is a Monday; 2026-06-20 is a Saturday.
const monday = (hhmm: string) => `2026-06-22T${hhmm}:00.000Z`;
const saturday = (hhmm: string) => `2026-06-20T${hhmm}:00.000Z`;

describe("outOfWindowGap — entry edge (early arrival)", () => {
  it("19:30 arrival to a 20:00 window owes 30 min", () => {
    const g = outOfWindowGap(night, "UTC", monday("19:30"), "entry");
    expect(g).not.toBeNull();
    expect(g!.minutes).toBe(30);
    expect(g!.start).toBe(monday("19:30"));
    expect(g!.end).toBe(monday("20:00"));
  });
  it("09:00 daytime arrival owes the whole gap to 20:00 (11h)", () => {
    const g = outOfWindowGap(night, "UTC", monday("09:00"), "entry");
    expect(g!.minutes).toBe(11 * 60);
    expect(g!.end).toBe(monday("20:00"));
  });
  it("in-window arrival (22:00) owes nothing", () => {
    expect(outOfWindowGap(night, "UTC", monday("22:00"), "entry")).toBeNull();
  });
  it("after-midnight in-window arrival (02:00) owes nothing", () => {
    expect(outOfWindowGap(night, "UTC", monday("02:00"), "entry")).toBeNull();
  });
});

describe("outOfWindowGap — exit edge (late departure)", () => {
  it("08:45 exit after an 08:00 window close owes 45 min", () => {
    const g = outOfWindowGap(night, "UTC", monday("08:45"), "exit");
    expect(g!.minutes).toBe(45);
    expect(g!.start).toBe(monday("08:00"));
    expect(g!.end).toBe(monday("08:45"));
  });
  it("in-window exit (07:00) owes nothing", () => {
    expect(outOfWindowGap(night, "UTC", monday("07:00"), "exit")).toBeNull();
  });
});

describe("outOfWindowGap — days the window doesn't apply", () => {
  it("a Saturday scan is free (window only Mon..Fri)", () => {
    expect(outOfWindowGap(night, "UTC", saturday("09:00"), "entry")).toBeNull();
    expect(outOfWindowGap(night, "UTC", saturday("23:30"), "exit")).toBeNull();
  });
  it("a window with no days (every day) DOES apply on Saturday", () => {
    const everyDay: PlanTimeframes = { fromMin: 1200, toMin: 480, tz: "UTC" };
    expect(outOfWindowGap(everyDay, "UTC", saturday("09:00"), "entry")).not.toBeNull();
  });
  it("an arbitrary day set (e.g. only Saturday) applies just then", () => {
    const satOnly: PlanTimeframes = { days: [6], fromMin: 1200, toMin: 480, tz: "UTC" };
    expect(outOfWindowGap(satOnly, "UTC", saturday("09:00"), "entry")).not.toBeNull();
    expect(outOfWindowGap(satOnly, "UTC", monday("09:00"), "entry")).toBeNull();
  });
});

describe("outOfWindowGap — grace tolerance", () => {
  const withGrace: PlanTimeframes = { ...night, graceMin: 15 };
  it("19:50 entry (10 min before open) is within a 15-min grace → no charge", () => {
    expect(outOfWindowGap(withGrace, "UTC", monday("19:50"), "entry")).toBeNull();
  });
  it("19:30 entry (30 min before) still charged, minus 15 grace = 15 min", () => {
    const g = outOfWindowGap(withGrace, "UTC", monday("19:30"), "entry");
    expect(g!.minutes).toBe(15);
  });
  it("08:10 exit within a 15-min grace of the 08:00 close → no charge", () => {
    expect(outOfWindowGap(withGrace, "UTC", monday("08:10"), "exit")).toBeNull();
  });
});

describe("outOfWindowGap — unrestricted", () => {
  it("null timeframes → never a charge", () => {
    expect(outOfWindowGap(null, "UTC", monday("09:00"), "entry")).toBeNull();
  });
});

describe("minutesOutsideWindow — the charge basis (regression: no phantom span)", () => {
  // entered 30 min before the 20:00 window; STILL inside, only a few minutes elapsed.
  it("early entry, barely elapsed → only the elapsed pre-window minutes (NOT back to a prior close)", () => {
    // 19:30 entry, now 19:33 → 3 minutes outside (the bug charged ~12h here).
    expect(minutesOutsideWindow(night, "UTC", monday("19:30"), monday("19:33"))).toBe(3);
  });
  it("early entry until the window opens = the full pre-window gap, then 0 inside", () => {
    // 19:30 → 22:00: 30 min outside (19:30→20:00), the rest in-window.
    expect(minutesOutsideWindow(night, "UTC", monday("19:30"), monday("22:00"))).toBe(30);
  });
  it("in-window the whole stay → 0", () => {
    expect(minutesOutsideWindow(night, "UTC", monday("22:00"), monday("23:30"))).toBe(90 - 90); // fully inside
  });
  it("late exit after close adds the post-close minutes", () => {
    // enter 22:00 (in window), exit 08:30 → 30 min outside (08:00→08:30).
    expect(minutesOutsideWindow(night, "UTC", monday("22:00"), `2026-06-23T08:30:00.000Z`)).toBe(30);
  });
  it("a day the window doesn't apply contributes 0 (weekend free)", () => {
    expect(minutesOutsideWindow(night, "UTC", saturday("09:00"), saturday("18:00"))).toBe(0);
  });
  it("unrestricted plan → 0", () => {
    expect(minutesOutsideWindow(null, "UTC", monday("09:00"), monday("23:00"))).toBe(0);
  });
});